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For heat treatment of tool and alloy steels, the end-user has a wide range of basic types of heat treating equipment to choose from. This article reviews them and details the criteria that must be considered in selecting equipment for a specific application. In making this choice, the most important criterion must be the quality of the tool or part after processing.
Electrification has already started to have a noticeable impact on the global automotive industry. As a result, the drivetrains of hybrid (HEV) and full electric vehicles (EV) are facing many challenges, like increased requirements for NVH in high speed e-Drives and the need for performance improvements to deal with recuperation requirements. Motivated by the positive validation results of surface densified manual transmission gears which are also applicable for dedicated hybrid transmissions (DHTs) like e-DCTs, GKN engineers have been looking for a more challenging application for PM gears within those areas.
The properties of both shot-peened and cold rolled PM gears are analyzed and compared. To quantify the effect of both manufacturing processes, the tooth root bending fatigue strength will be evaluated and compared to wrought gears.
Design innovation, superior engineering properties, high end-market visibility and sustainability distinguish the winners of the 2011 Design Excellence awards, the annual powder metallurgy (PM) design competition sponsored by the Metal Powder Industries Federation.
The heat treatment processing of powder metal (PM) materials like Astaloy requires four steps -- de-waxing, HT sintering, carburizing and surface hardening -- which are usually achieved in dedicated, atmospheric furnaces for sintering and heat treat, respectively, leading to intermediate handling operations and repeated heating and cooling cycles. This paper presents the concept of the multi-purpose batch vacuum furnace, one that is able to realize all of these steps in one unique cycle. The multiple benefits brought by this technology are summarized here, the main goal being to use this technology to manufacture high-load transmission gears in PM materials.
Question: We just received permission to purchase our first CNC gear inspection system. With capital approvals so hard to come by, especially for inspection equipment, I want to be sure to purchase a system I can count of for years to come. My past experience with purchasing CNC equipment has shown me that serviceability of the computer and the CNC controller portion of the system can be a problem in just a few years because of the obsolescence factor. What information do I need to look for when selecting a supplier to reduce the risk of obsolescence, as well as to reduce the long-term servicing costs in the computer and controls portion of the system?
Capstan Atlantic, located in Wrentham, Massachusetts, produces powder metal gears, sprockets and complex structural components. The company has provided unique powder metal products in a variety of industries including automotive, business machines, appliances, lawn and garden equipment and recreational vehicles.
Gear metrology is a revolving door of software packages and system upgrades. It has to be in order to keep up with the productivity and development processes of the machines on the manufacturing floor. Temperature compensation, faster inspection times and improved software packages are just a few of the advancements currently in play as companies prepare for new opportunities in areas like alternative energy, automotive and aerospace/defense.
Good timing leads to partnership between Process Equipment and Schafer Gear.
Except for higher-end gear applications found in automotive and aerospace transmissions, for example, high-performance, sintered-steel gears match wrought-steel gears in strength and geometrical quality. The enhanced P/M performance is due largely to advances in powder metallurgy over last two decades, such as selective surface densification, new materials and lubricants for high density and warm-die pressing. This paper is a review of the results of a decade of research and development of high- performance, sintered-steel gear prototypes.
The complete Industry News section from the July 2014 issue of Gear Technology.
The complete Industry News section from the August 2014 issue of Gear Technology.
PowderMet 2009, plus the full technical calendar for Gear Technology's June 2009 issue.
When sending gears to be heat treated, manufacturers can end up unwittingly making mistakes that slow down turnaround time. We talked to some heat treaters to get their best advice on how you can help them help you.
Safe cutting tool clamping, superfinishing gear shafts, gearbox parts cleaning, gear deburring and more new gear-related products.
Powder metal (PM) gears normally sell due to the lower cost and their relatively high mechanical performance. The reason behind the lower cost is that most of the machining is omitted due to the net-shape forming process. So how net-shape are powder metal gears? In this article some hard-to-find information about the tolerances through the manufacturing steps will be presented.
This paper analyzes the different influences of the deviations between nominal and actual geometry for a first-cut bevel gear. In each section, the customary tolerances are quantified and the possibilities to reduce them are discussed.
Part I of this paper, which appeared in the January/February issue of Gear Technology, described the theory behind double-flank composite inspection. It detailed the apparatus used, the various measurements that can be achieved using it, the calculations involved and their interpretation. The concluding Part II presents a discussion of the practical application of double-flank composite inspection -- especially for large-volume operations. It also addresses statistical techniques that can be used in conjunction with double-flank composite inspection, as well as an in-depth analysis of gage R&R for this technique.
Gear pitting is one of the primary failure modes of automotive transmission gear sets. Over the past years, many alternatives have been intended to improve their gear surface durability. However, due to the nature of new process development, it takes a length of time and joint efforts between the development team and suppliers to investigate and verify each new approach.
For metal replacement with powder metal (PM) of an automotive transmission, PM gear design differs from its wrought counterpart. Indeed, complete reverse-engineering and re-design is required so to better understand and document the performance parameters of solid-steel vs. PM gears. Presented here is a re-design (re-building a 6-speed manual transmission for an Opel Insignia 4-cylinder, turbocharged 2-liter engine delivering 220 hp/320 N-m) showing that substituting a different microgeometry of the PM gear teeth -- coupled with lower Youngâs modulus -- theoretically enhances performance when compared to the solid-steel design.
This paper will provide examples of stress levels from conventional root design using a hob and stress levels using an optimized root design that is now possible with PM manufacturing. The paper will also investigate how PM can reduce stresses in the root from transient loads generated by abusive driving.
Previews of manufacturing technology related to gears that will be on display at IMTS 2012.
The implementation of powder metal (PM)components in automotive applications increases continuously, in particular for more highly loaded gear components like synchromesh mechanisms. Porosity and frequently inadequate material properties of PM materials currently rule out PM for automobile gears that are subject to high loads. By increasing the density of the sintered gears, the mechanical properties are improved. New and optimized materials designed to allow the production of high-density PM gears by single sintering may change the situation in the future.
the gear industry is awash in manufacturing technologies that promise to eliminate waste by producing gears in near-net shape, cut production and labor costs and permit gear designers greater freedom in materials. These methods can be broken down into the following categories: alternative ways to cut, alternative ways to form and new, exotic alternatives. Some are new, some are old and some are simply amazing.
There's a reason they call it catastrophic gear failure: For example, if the line goes down at a large aluminum rolling mill because a gear set goes bad, the cost can run up to a whopping $200,000 a week. Even in smaller operations, the numbers alone (not to mention all the other problems) can be a plant manager's worst nightmare.
Bringing new or improved products to market sooner has long been proven profitable for companies. One way to help shorten the time-to-market is to accelerate validation testing. That is, shorten the test time required to validate a new or improved product.
Meeting the many challenges of large gear inspection.
A new inspection method has several advantages over traditional methods, especially for very large or very small gears.
A trial test of the calibration procedures outlined in ISO 18653âGears: Evaluation of Instruments for the Measurement of Individual Gears, shows that the results are reasonable, but a minor change to the uncertainty formula is recommended. Gear measuring machine calibration methods are reviewed. The benefits of using workpiece-like artifacts are discussed, and a procedure for implementing the standard in the workplace is presented. Problems with applying the standard to large gear measuring machines are considered and some recommendations offered.
Computer technology has touched all areas of our lives, impacting how we obtain airline tickets, purchase merchandise and receive medical advice. This transformation has had a vast influence on manufacturing as well, providing process improvements that lead to higher quality and lower costs. However, in the case of the gear industry, the critical process of tooth contact pattern development for spiral bevel gears remains relatively unchanged.
This article is the fourth installment in Gear Technology's series of excerpts from Dr. Hermann J. Stadtfeld's book, Gleason Bevel Gear Technology. The first three excerpts can be found in our June, July and August 2015 issues. In the previous chapter, we demonstrated the development of a face-milled spiral bevel gearset. In this section, an analogue face-hobbed bevel gearset is derived.
In the previous sections, the development of conjugate bevel gearsets via hand calculations was demonstrated. The goal of this exercise was to encourage the reader to gain a basic understanding of the theory of bevel gears. This knowledge will help gear engineers to better judge bevel gear design and their manufacturing methods. In order to make the basis of this learning experience even more realistic, this chapter will convert a conjugate bevel gearset into a gearset that is suitable in a real-world application. Length and profile crowning will be applied to the conjugate flank surfaces. Just as in the previous chapter, all computations are demonstrated as manual hand calculations. This also shows that bevel gear theory is not as complicated as commonly assumed.
Alongside the macro test parameters on tooth flanks for profile and tooth traces, surface properties (roughness) play a decisive role in ensuring proper toothed gear function. This article addresses roughness measurement systems on tooth flanks. In addition to universal test equipment, modified test equipment based on the profile method for use on gears is addressed in particular. The equipment application here refers to cylindrical gear flanks and bevel gear flanks. The most important roughness parameters, as well as the implementation of the precise measurement procedure will also be described under consideration of the applicable DIN EN ISO standards as well as the current VDI/VDE Directive 2612 Sheet 5.
It's the New Year, and with it comes the opportunity to take a fresh look at your business objectives. Because business development is such a vital part of running a company, I'd like to present some guidelines I have found beneficial for securing new work and new customers.
Many potential problems are not apparent when using new induction heat treating systems. The operator has been trained properly, and setup parameters are already developed. Everything is fresh in one's mind. But as the equipment ages, personnel changes or new parts are required to be processed on the old equipment ages, personnel changes or new parts are required to b processed on the old equipment, important information can get lost in the shuffle.
Traditionally, high-quality gears are cut to shape from forged blanks. Great accuracy can be obtained through shaving and grinding of tooth forms, enhancing the power capacity, life and quietness of geared power transmissions. In the 1950s, a process was developed for forging gears with teeth that requires little or no metal to be removed to achieve final geometry. The initial process development was undertaken in Germany for the manufacture of bevel gears for automobile differentials and was stimulated by the lack of available gear cutting equipment at that time. Later attention has turned to the forging of spur and helical gears, which are more difficult to form due to the radial disposition of their teeth compared with bevel gears. The main driver of these developments, in common with most component manufacturing, is cost. Forming gears rather than cutting them results in increased yield from raw material and also can increase productivity. Forging gears is therefore of greater advantage for large batch quantities, such as required by the automotive industry.
The advent of CNC technology as applied to gear shaping machines has, in the last 10 years, led to an astonishing improvement in both productivity and quality. As is usual when developments such as this take place, the technology of the machine tool suddenly jumps ahead of that of the cutting tool, and the machine is then capable of producing faster than the cutting tool can withstand.
The International Manufacturing Technology Show provided one of the biggest ever marketplaces for buying and selling gear-making equipment, with 121601 attenders, making it the largest IMTS ever. The show took place September 4-11 at McCormick Place in Chicago, IL.
Faith â paraphrasing the gospels of Matthew and Mark â can move mountains. But it helps if you have precision geared equipment.
How the latest techniques and software enable faster spiral bevel and hypoid design and development.
Several innovations have been introduced to the gear manufacturing industry in recent years. In the case of gear hobbingâthe dry cutting technology and the ability to do it with powder-metallurgical HSSâmight be two of the most impressive ones. And the technology is still moving forward. The aim of this article is to present recent developments in the field of gear hobbing in conjunction with the latest improvements regarding tool materials, process technology and process integration.
The most conclusive test of bevel and hypoid gears is their operation under normal running conditions in their final mountings. Testing not only maintains quality and uniformity during manufacture, but also determines if the gears will be satisfactory for their intended applications.
Recently, I was approached by a colleague who is a manufacturer outside the gear industry...
During the last decade, industrial gear manufacturers, particularly in Europe, began to require documentation of micropitting performance before approving a gear oil for use in their equipment. The development of micropitting resistant lubricants has been limited both by a lack of understanding of the mechanism by which certain lubricant chemistry promotes micropitting and by a lack of readily available testing for evaluation of the micropitting resistance of lubricants. This paper reports results of two types of testing: (1) the use of a roller disk machine to conduct small scale laboratory studies of the effects of individual additives and combinations of additives on micropitting and (2) a helical gear test used to study micropitting performance of formulated gear oils.
Primitive gears were known and used well over 2,000 years ago, and gears have taken their place as one of the basic machine mechanisms; yet, our knowledge and understanding of gearing principles is by no means complete. We see the development of faster and more reliable gear quality assessment and new, more productive manufacture of gears in higher materials hardness states. We have also seen improvement in gear applications and design, lubricants, coolants, finishes and noise and vibration control. All these advances push development in the direction of smaller, more compact applications, better material utilization and improved quietness, smoothness of operation and gear life. At the same time, we try to improve manufacturing cost-effectiveness, making use of highly repetitive and efficient gear manufacturing methods.
In order to reduce costs for development and production, the objective in gearbox development and design is to predict running and noise behavior of a gearbox without manufacturing a prototype and running expensive experimental investigations. To achieve this objective, powerful simulation models have to be set up in a first step. Afterwards, those models have to be qualified and compared to experimental investigations. During the investigation procedure of gearboxes, there are two possibilities to evaluate the running and noise behavior: quasi-static and dynamic investigations. In times of engine downsizing, e-mobility and lightweight design, the dynamic excitation behavior is becoming increasingly important.
It is with great anticipation that we move closer to AGMA's Fall Technical Conference and Gear Expo '87, which is being held on Oct. 4-6 in Cincinnati, OH. This bold undertaking by both AGMA and the exhibitors in the Expo's 160 booths is an attempt to make a major change in the industry's approach to the exposition of gear manufacturing equipment. By combining the Expo with the Fall Technical Conference, those involved in gear manufacturing will have the opportunity to review the latest equipment, trends, and most innovative ideas, while keeping up with the newest technology in the industry.
A fundamental characteristic of the gear industry is that it is capital intensive. In the last decade, the gear manufacturing industry has been undergoing an intense drive toward improving and modernizing its capital equipment base. The Department of Commerce reports that annual sales of gear cutting equipment have increased nearly 60% since 1990. While this effort has paid off in increased competitiveness for the American gear industry, it is important to remember that there is another capital crucial to manufacturing success - "human capital."
This article examines the dry hobbing capabilities of two cutting tool materialsâpowder metallurgical high-speed steel (PM-HSS) and cemented carbide. Cutting trials were carried out to analyze applicable cutting parameters and possible tool lives as well as the process reliability. To consider the influences of the machinability of different workpiece materials, a case hardening steel and a tempered steel were examined.
In todayâs manufacturing environment, shorter and more efficient product development has become the norm. It is therefore important to consider every detail of the development process, with a particular emphasis on design. For green machining of gears, the most productive and important process is hobbing. In order to analyze process design for this paper, a manufacturing simulation was developed capable of calculating chip geometries and process forces based on different models. As an important tool for manufacturing technology engineers, an economic feasibility analysis is implemented as well. The aim of this paper is to show how an efficient process designâas well as an efficient processâcan be designed.
Powder metallurgy (P/M) techniques have proven successful in displacing many components within the automobile drive train, such as: connecting rods, carriers, main bearing caps, etc. The reason for P/Mâs success is its ability to offer the design engineer the required mechanical properties with reduced component cost.
Industrial gear standards have been used to support reliability through the specification of requirements for design, manufacturing and verification. The consensus development of an international wind turbine gearbox standard is an example where gear products can be used in reliable mechanical systems today. This has been achieved through progressive changes in gear technology, gear design methods and the continual development and refinement of gearbox standards.
Metrology is a vital component of gear manufacturing. Recent changes in this area, due in large part to the advent of computers, are highlighted in this article by comparison with more traditional methods.
This paper describes the research and development of the first production gearbox with asymmetric tooth profiles for the TV7-117S turboprop engine. The paper also presents numerical design data related to development of this gearbox.
Conical involute gears (beveloids) are used in transmissions with intersecting or skewed axes and for backlash-free transmissions with parallel axes.
In a capitalist society, the way things usually work is that government and academia focus on research and development, while industry focuses on commercialization. The result is an increasingly wide disconnect in the applied research sector, which deals primarily with technology development and demonstration.
Chairman Todd Praneis of Cotta Transmission describes the activities of AGMA's Enclosed Drives technical committee.
The metal powder industry gathered in force this past June for PowderMet 2010, the 2010 International Conference on Powder Metallurgy and Particulate Materials.
I must admit that after thumbing through the pages of this relatively compact volume (113 pages, 8.5 x 11 format), I read its three chapters(theory of gearing, geometry and technology, and biographical history) from rear to front. It will become obvious later in this discussion why I encourage most gear engineers to adopt this same reading sequence!
Gear manufacturing schedules that provide both quality and economy are dependent on efficient quality control techniques with reliable measuring equipment. Given the multitude of possible gear deviations, which can be found only by systematic and detailed measuring of the gear teeth, adequate quality control systems are needed. This is especially true for large gears, on which remachining or rejected workpieces create very high costs. First, observation of the gears allows adjustment of the settings on the equipment right at the beginning of the process and helps to avoid unproductive working cycles. Second, the knowledge of deviations produced on the workpiece helps disclose chance inadequacies on the production side: e.g., faults in the machines and tools used, and provides an opportunity to remedy them.
The powder metal (P/M) process is making inroads in automotive transmission applications due to substantially lower costs of P/M-steel components for high-volume production, as compared to wrought or forged steel parts. Although P/M gears are increasingly used in powered hand tools, gear pumps and as accessory components in automotive transmissions, P/M-steel gears are currently in limited use in vehicle transmission applications. The primary objective of this project was to develop high-strength P/M-steel gears with bending fatigue, impact resistance and pitting fatigue performance equivalent to current wrought steel gears.
Bore finishing system from Sunnen helps Cloyes Gear and Products achieve high accuracy, productivity and process capability.
QuesTek Innovations LLC is applying its Materials by Design computational design technology to develop a new class of high-strength, secondary hardening gear steels that are optimized for high-temperature, low-pressure (i.e., vacuum) carburization. The new alloys offer three different levels of case hardness (with the ability to âdial-inâ hardness profiles, including exceptionally high case hardness), and their high core strength, toughness and other properties offer the potential to reduce drivetrain weight or increase power density relative to incumbent alloys such as AISI 9310 or Pyrowear Alloy 53.
Multiple possibilities are available to increase the transmissible power of girth gears. These solutions include: using a larger module, increasing of the gear diameter through the number of teeth, enlarging the face width, and increasing the hardness of the base material. The first three parameters are mostly limited by cutting machine capability. Module, outside diameter, and face width (for a cast gear) can theoretically be increased to infinity, but not the cutting machine dimensions. There are also practical limits with respect to the installation of very large diameter/large face width gears.
It is becoming increasingly apparent that material properties can and will play a greater role than before in addressing the challenges most transmission manufacturers are facing today. Making use of materials' intrinsic fatigue properties provides a new design tool to support the market changes taking place.
How machine tool maintenance has evolved in recent years in gear manufacturing.
The major focus of the American Gear Manufacturers Association standards activity has been the accurate determination of a gearbox's ability to transmit a specified amount of power for a given amount of time. The need for a "level playing field" in the critical arena was one of the reasons the association was formed in the first place. Over the past 85 years, AGMA committees have spent countless hours "discussing" the best ways to calculate the rating of a gear set, often arguing vigorously over factors that varied the resulting answers by fractions of a percentage point. While all that "science" was being debated in test labs and conference rooms all over the country, out industry's customers were conducting their own experiments through the daily operation of gear-driven equipment of all types.
Gear tooth wear and micropitting are very difficult phenomena to predict analytically. The failure mode of micropitting is closely correlated to the lambda ratio. Micropitting can be the limiting design parameter for long-term durability. Also, the failure mode of micropitting can progress to wear or macropitting, and then go on to manifest more severe failure modes, such as bending. The results of a gearbox test and manufacturing process development program will be presented to evaluate super-finishing and its impact on micropitting.
Recent trends in gear cutting technology have left process engineers searching for direction about which combination of cutting tool material, coating, and process technology will afford the best quality at the lowest total cost. Applying the new technologies can have associated risks that may override the potential cost savings. The many interrelated variables to be considered and evaluated tend to cloud the issue and make hobbing process development more difficult.
The tooth-by-tooth, submerged induction hardening process for gear tooth surface hardening has been successfully performed at David Brown for more than 30 years. That experience - backed up by in-depth research and development - has given David Brown engineers a much greater understanding of, and confidence in, the results obtainable from the process. Also, field experience and refinement of gear design and manufacturing procedures to accommodate the induction hardening process now ensure that gears so treated are of guaranteed quality.
The goal of gear drive design is to transit power and motion with constant angular velocity. Current trends in gear drive design require greater load carrying capacity and increased service life in smaller, quieter, more efficient gearboxes. Generally, these goals are met by specifying more accurate gears. This, combined with the availability of user-friendly CNC gear grinding equipment, has increased the use of ground gears.
It used to be that gear manufacturers wanting to perform analytical gear inspection required at least three machines to do so: The lead measuring instrument, the tooth space comparator and the involute checking instrument. In the beginning, these machines were mechanically driven. Over the years, the manufacturers of analytical gear inspection equipment have combined these functions - and a host of others.
Plastics as gear materials represent an interesting development for gearing because they offer high strength-to-weight ratios, ease of manufacture and excellent tribological properties (Refs. 1-7). In particular, there is a sound prospect that plastic gears can be applied for power transmission of up to 10 kW (Ref. 6).
Long-time readers of these pages will know that I have always felt strongly about the subject of professional education. There's nothing more important for an individual's career development than keeping up with current technology. likewise, there's nothing more important that a company can do for itself and it employees than seeing to it they have the professional education they need. Giving people the educational tools they need to do their jobs is a necessary ingredient for success.
I'm a big believer in the value of IMTS as a marketplace where gear manufacturers can go and look at the latest machine tools and processes; compare hobbing machines, gear grinders and inspection equipment; see turning, milling or grinding machines in action; and ask questions of the various vendors all in one place. This year's IMTS promised to be the biggest ever, and I have no doubt that it will be a valuable experience to those who go there looking for ways to improve the way they manufacture products.
Thousands of gear industry professionals will converge October 24-27 in Nashville, TN, for Gear Expo 99, the industry's biennial collection of the latest in gear manufacturing technology. With nearly 50,000 square feet of exhibit space sold more than two months in advance of the show, this year's Gear Expo will offer visitors more opportunity for supplier comparison than ever before. As of July 20, 166 suppliers of equipment, tooling, services and precision gear products were scheduled to participate, with as many as 20 additional booths yet to be sold, according to AGMA vice president and Gear Expo show manager Kurt Medert. The largest previous Gear Expo was held in 1997 in Detroit, with 43,100 square feet of exhibit space and 161 exhibitors.
Although the cultures and areas of expertise of Solomon and Sun Tzu are worlds apart, the two offer similar opinions on the importance of seizing the moment. Their ancient wisdom may have increasing relevance to modern manufacturers in a global economy, particularly those contemplating whether now is the time to invest in capital equipment.
The efficient and reliable transmission of mechanical power continues, as always, to be a central area of concern and study in mechanical engineering. The transmission of power involves the interaction of forces which are transmitted by specially developed components. These components must, in turn, withstand the complex and powerful stresses developed by the forces involved. Gear teeth transmit loads through a complex process of positive sliding, rolling and negative sliding of the contacting surfaces. This contact is responsible for both the development of bending stresses at the root of the gear teeth and the contact stresses a the contacting flanks.
The Gear Research Laboratory of the University of Illinois at Chicago is home to a unique tribute to gear pioneers from around the world, the Gallery of Fame. The gallery is the brainchild of the laboratory director, Professor Faydor L. Litvin. The Gallery was begun in 1994 an dis a photographic tribute to those gear company founders, inventors and researchers who devoted their careers to the study and development of gears.
Air compressors are a good example of industrial machinery with components that rotate at very high speeds, up to 80,000 rpm. They are subject to very high rotational forces and often variable loads. Strong, high-precision gears for the power transmission trains that drive the impellers are critical components of machinery operating under such conditions.
ISO 6336 Calculation of Load Capacity of Spur and Helical Gears was published in 1997 after 50 years of effort by an international committee of experts whose work spanned three generations of gear technology development. It was a difficult compromise between the existing national standards to get a single standard published which will be the basis for future work. Many of the compromises added complication to the 1987 edition of DIN 3990, which was the basic document.
The American Gear Manufacturers Association (AGMA) is accredited by the American National Standards Institute (ANSI) to write all U.S. standards on gearing. However, in response to the growing interest in a global marketplace, AGMA became involved with the International Standards Organization (ISO) several years ago, first as an observer in the late 1970s and then as a participant, starting in the early 1980s. In 1993, AGMA became Secretariat (or administrator) for Technical Committee 60 of ISO, which administers ISO gear standards development.
Several articles have appeared in this publication in recent years dealing with the principles and ways in which the inspection of gears can be carried out, but these have dealt chiefly with spur, helical and bevel gearing, whereas worm gearing, while sharing certain common features, also requires an emphasis in certain areas that cause it to stand apart. For example, while worm gears transmit motion between nonparallel shafts, as do bevel and hypoid gears, they usually incorporate much higher ratios and are used in applications for which bevel would not be considered, including drives for rotary and indexing tables in machine tools, where close tolerance of positioning and backlash elimination are critical, and in situations where accuracy of pitch and profile are necessary for uniform transmission at speed, such as elevators, turbine governor drives and speed increasers, where worm gears can operate at up to 24,000 rpm.
In 1961 I presented a paper, "Calculating Conjugate Helical Forms," at the semi-annual meeting of the American Gear Manufacturers Association (AGMA). Since that time, thousands of hobs, shaper cutters and other meshing parts have been designed on the basis of the equations presented in that paper. This article presents the math of that paper without the formality of its development and goes on to discuss its practical application.
Gleason Corporation has announced that agreement has been reached on all terms to acquire for approximately $36 million in cash the Hermann Pfauter Group, including, among other operations, Hermann Pfauter GmbH & Co., a privately held leading producer of gear equipment based in Ludwigsburg, Germany; its 76% interest in Pfauter-Maad Cutting Tools, a leading cutting tool manufacturer basked in Loves Park, IL; and Pfauter-Maag management's 24% ownership interest in that company. The acquisition includes all assets and liabilities, including the assumption of approximately $56 million in bank debt.
In 1993, M & M Precision Systems was awarded a three-year, partial grant from the Advanced Technology Program of the Department of Commerce's National Institute of Standards and Technology (NIST). Working with Pennsylvania State University, M&M embarked on a technology development project to advance gear measurement capabilities to levels of accuracy never before achieved.
This article summarizes the development of an improved titanium nitride (TiN) recoating process, which has, when compared to conventional recoat methods, demonstrated tool life increases of up to three times in performance testing of hobs and shaper cutters. This new coating process, called Super TiN, surpasses the performance of standard TiN recoating for machining gear components. Super TiN incorporates stripping, surface preparation, smooth coating techniques and polishing before and after recoating. The combination of these improvements to the recoating process is the key to its performance.
Romax Technology, the gearbox, bearing and driveline engineering specialist, has launched a new design software package that will increase speed, quality, creativity and innovation when designing gearboxes and drivelines. Called Concept, the new product delivers on the Romax vision of streamlining the end-to-end, planning-to-manufacture process with open, easy to use software solutions. It has been developed in close collaboration with engineers in the largest ground vehicle, wind energy and industrial equipment companies around the globe.
A large number of technologies aimed primarily at higher productivity were presented by exhibitors at the AMB, International Exhibition for Metal Working at the Stuttgart Trade Fair Centre in September. Following the successful 2010 show, AMB 2012 boasted further developments in energy and resource efficiency, higher productivity, life cycle performance, quality assurance and user-friendliness.
Background on the development of a high-speed, automatic hardness tester for gear steels.
Although a cell is dedicated to produce a single part family, it must have the requisite equipment capabilities, routing flexibility, cross-trained employees and, to the extent possible, minimal external process dependencies. Cells are often implemented in job shops since they provide the operational benefits of flowline production.
Suppliers are working hard to make sure their heat treating equipment is controllable, repeatable and efficient, and manufacturers continue to incorporate technology that gives heat treaters and their customers more information about what's going on inside the magic box.
Question: I am a gear engineer for a motor manufacturer in China. I am writing about noise generated from cross-helical gear assembly error. I want to learn the relationship between the misalignment (center distance change and cross-angle shift) and transmission error. It is better under the loading and theory conditions. What is the trend of cross-helical gear development (use ZI worm and involute helical gear, point contact)?
Historically, gearbox original equipment manufacturers (OEMs) and repair organizations have tended to offer their customers no-load, full speed (spin) tests as a standard performance test. If a load test was specified, the supplier would probably offer a locked torque back-to-back simulated load test, which requires a large investment in tooling to connect shafts of the test and slave gearboxes.
Technical articles have been the hallmark of Gear Technology since we first started publishing, more than 34 years ago, in 1984. One of the achievements IĂą??m most proud of is the development of the GT LIBRARY at geartechnology.com, where you can find every single one of those articles, going all the way back to the beginning.
Delta Research upgrades its Gleason Metrology Workhorses to meet the development requirements of the latest electrical drive vehicles.
Despite the development and availability of a number of newly engineered, rugged materials intended for plastic gear applications, some engineers/designers continue to believe metal is better.
"Documentation is not a Substitute for an Intuitive Interface." The author explores the development of modern controls for a CNC gear grinding machine.
There are many different causes of gear noise, all of them theoretically preventable. Unfortunately, the prevention methods can be costly, both in equipment and manpower. If the design of the gear and its application are appropriate, in theory all that is necessary is to have a tight control on the process of producing the finished gear. In reality, there are many variables that can cause a process, no matter how well-controlled, to deteriorate, and thus cause errors, some of which will cause a gear to produce unwanted noise when put to use.
Gear designers face constant pressure to increase power density in their drivetrains. In the automotive industry, for example, typical engine torque has increased significantly over the last several decades. Meanwhile, the demands for greater fuel efficiency mean designers must accommodate these increased loads in a smaller, more lightweight package than ever before. In addition, electric and hybrid vehicles will feature fewer gears, with fewer transmission speeds, running at higher rpms, meaning the gears in those systems will have to endure life cycles far beyond what is typical with internal combustion engines.
A key part of gear design software development is customer feedback. With the right feedback, you can get your software developer to work for you to provide the most relevant features possible.
First, the facts: powder metallurgy is a cost-effective method of forming precision net-shape metal components that allows for more efficiently designed products. It saves valuable raw materials through recycling and the elimination of costly secondary-machining. PM competes with wrought steel gears as the technology continues to advance. You'll find PM components in everything from automobile transmissions to aircraft turbine engines, surgical equipment and power tools.
I'm sure it comes as no surprise that finding skilled people to work in your manufacturing facility is no simple task. But after finding them, and investing in the development of their abilities, what happens when one of them - an employee your company really needs - becomes a troublesome employee? This is among the trickiest situations a manager can face.
Skiving will be front and center when the gear industry comes together in Columbus this October. Attendees will find dedicated skiving equipment, multifunctional machines with skiving options and a slew of new cutting tools, machine designs and modifications to make the process more efficient and robust.
In several applications like hoisting equipment and cranes, open gears are used to transmit power at rather low speeds (tangential velocity < 1m/s) with lubrication by grease. In consequence those applications have particularities in terms of lubricating conditions and friction involved, pairing of material between pinion and gear wheel, lubricant supply, loading cycles and behavior of materials with significant contact pressure due to lower number of cycles.
This paper introduces the latest process developments for the hard-finishing of gears, specifically in regard to controlling the so-called flank twist.
The latest in machine tools, cutting tools, inspection equipment, shop floor gages and other products for the gear industry.
Market needs push in 2013, but will it get one? The construction/off-highway industries have been here before. New equipment, technologies and innovations during an economic standstill that some have been dealing with since 2007.
Peter Eelman has been involved with the International Manufacturing Technology Show for more than 30 years. First as an exhibitor with Warner & Swasey Co.; later with Toyoda USA; later still as a consultant; and currently as vice president for exhibitions and business development, IMTS. He also serves on the board of directors of the exhibitor-appointed Contractor Association and is a former member of the board of directors for the Trade Show Exhibitors Association. Eelman is a speaker with the International Association of Exhibitions and Events and serves on the Metropolitan Chicago Pier & Exposition Authority Labor Council. As the head of IMTS, Eelman is the go-to, make-things-happen guy for the Chicago Convention and Tourism Bureau, the Metropolitan Pier and Exposition Authority, McCormick Place and the various vendors, service providers and trade unions involved in the complex trade show process. In addition to IMTS, Eelman is also prominently involved in shows with an international presence.
Chapter 2, Continued In the previous sections, development of conjugate, face milled as well as face hobbed bevel gearsets - including the application of profile and length crowning - was demonstrated. It was mentioned during that demonstration that in order to optimize the common surface area, where pinion and gear flanks have meshing contact (common flank working area), a profile shift must be introduced. This concluding section of chapter 2 explains the principle of profile shift; i.e. - how it is applied to bevel and hypoid gears and then expands on profile side shift, and the frequently used root angle correction which - from its gear theoretical understanding - is a variable profile shift that changes the shift factor along the face width. The end of this section elaborates on five different possibilities to tilt the face cutter head relative to the generating gear, in order to achieve interesting effects on the bevel gear flank form. This installment concludes chapter 2 of the Bevel Gear Technology book that lays the foundation of the following chapters, some of which also will be covered in this series.
Due to increasing requirements regarding the vibrational behavior of automotive transmissions, it is necessary to develop reliable methods for noise evaluation and design optimization. Continuous research led to the development of an elaborate method for gear noise evaluation. The presented methodology enables the gear engineer to optimize the microgeometry with respect to robust manufacturing.
Reshoring offers an opportunity for increased domestic gear production. Reshoring is growing at a steady pace in most industries, and is particularly strong in the gear intensive industries such as automotive, aerospace and construction equipment (Table 1). This article provides background on the overall trend and tools for the gear buyer and the gear producer to make the offshore vs. domestic decision.
Prior to receiving airworthiness certification, extensive testing is required during the development of rotary wing aircraft drive systems. Many of these tests are conducted to demonstrate the drive systemâs ability to operate at extreme conditions, i.e. â beyond that called for in the normal to maximum power operating range.
Liebherr is well-known as one of the worldâs largest privately owned companies â a titan in heavy industry specializing in cranes, trucks and mammoth earth moving and mining equipment.
NVH â noise, vibration and harshness â is a key issue in the design and development of modern transmission and driveline systems.
Were Thomas Jefferson around today, he'd be all over the Double-A engine's development and everything it represents. And what is the Double-A engine; what does its successful design and execution represent, you ask?
Over the past few months I've talked with several different gear manufacturers who are in the process of upgrading their gear making equipment with modern CNC machine tools. Each of these manufacturers has come to the realization that in order to stay competitive, he needs to streamline operations and become more efficient...
The long and colorful history of aviation is comprised of many chapters and giants. The chapter we're reviewing in this installment of Addendum is the invention and development of the retractable landing gear.
The grinding/abrasives market is rapidly changing, thanks to new technology, more flexibility and an attempt to lower customer costs. Productivity is at an all-time high in this market, and itâs only going to improve with further R&D. By the time IMTS 2014 rolls around this September, the gear market will have lots of new toys and gadgets to offer potential customers. If you havenât upgraded any grinding/abrasives equipment in the last five years, now might be a good time to consider the investment.
Although a comprehensive on-site gearbox inspection is desirable in many situations, there may be constraints that limit the extent of the inspection such as cost, time, accessibility and qualified personnel. This article describes the equipment and techniques necessary to perform an on-site gearbox inspection.
Following is a report from The Manufacturers Alliance for Productivity and Innovation (MAPI). Founded in 1933, the alliance contributes to the competitiveness of U.S. manufacturing by providing economic research, professional development, and an independent, expert source of manufacturing information.
For two days in Saline, Michigan, Liebherr's clients, customers and friends came together to discuss the latest gear products and technology. Peter Wiedemann, president of Liebherr Gear Technology Inc., along with Dr.-Ing. Alois Mundt, managing director, Dr.-Ing. Oliver Winkel, head of application technology, and Dr.-Ing. Andreas Mehr, technology development shaping and grinding, hosted a variety of informative presentations.
Standards are unlike gears themselves: mundane, but complex, ubiquitous and absolutely vital. Standards are a lingua franca, providing a common language with reference points for evaluating product reliability and performance for manufacturers and users. The standards development process provides a scientific forum for discussion of product design, materials and applications, which can lead to product improvement. Standards can also be a powerful marketing tool for either penetrating new markets or protecting established ones.
NC and CNC metal cutting machines are among the most popular machine tools in the business today, There is also a strong trend toward using flexible machining centers and flexible manufacturing systems. The same trend is apparent in gear cutting. Currently the trend toward CNC tools has increased, and sophisticated controls and peripheral equipment for gear cutting machines are now available; however, the investment in a CNC gear machine has to be justified on the basis of economic facts as well as technical advantages.
IMTS: It can be the best of times or the worst of times. The best because nowhere will you find more equipment, products and services for your business than at McCormick Place, Chicago, in September; the worst because finding your way around the show and around the city can be a hassle.
The United Statesâ long-held dream of energy independenceâas in cheap, clean, free of overseas extortion and renewable energyâcould very well be realized in part by the country-wide development of wind turbines...
The heat treating of gears presents a difficult challenge to both the heat treater and the gear manufacturer. The number and variety of variables involved in the manufacturing process itself and the subsequent heat treating cycle create a complex matrix of factors which need to be controlled in order to produce a quality product. A heat treater specializing in gears or a gear manufacturer doing his own heat treating must have a clear understanding of these issues in order to deliver a quality product and make a profit at the same time. The situation also presents a number of areas that could benefit greatly from continued research and development.
This article describes some of the most important tests for prototypes conducted at Winergy AG during the product development process. It will demonstrate that the measurement results on the test rig for load distribution are in accordance with the turbine measurements.
AGMA Flexible Couplings committee chairman Glenn C. Pokrandt gives an update about standards and other documents under development.
Machine tool companies are expanding capabilities to better accommodate the changing face of manufacturing. Customers want smaller-sized equipment to take up less valuable floor space, multifunctional machines that can handle a variety of operations and easy set-up changes that offer simplified operation and maintenance.
Bradley University and Winzeler Gear collaborate on the design and development of an urban light vehicle.
Minimizing gear losses caused by churning, windage and mesh friction is important if plant operating costs and environmental impact are to be minimized. This paper concentrates on mesh friction losses and associated scuffing risk. It describes the preliminary results from using a validated, 3-D Finite Element Analysis (FEA) and Tooth Contact Analysis (TCA) program to optimize cylindrical gears for low friction losses without compromising transmission error (TE), noise and power density. Some case studies and generic procedures for minimizing losses are presented. Future development and further validation work is discussed.
Investment in Gleason GMM Series inspection equipment helps drive Milwaukee Gear's expansion into profitable new markets around the worldâall hungry for high-precision custom gears and gear drives.
In the hypercompetitive race to increase automobile efficiency, Metaldyne has been developing its balance shaft module line with Victrex PEEK polymer in place of metal gears. The collaborative product development resulted in significant reductions in inertia, weight and power consumption, as well as improvement in noise, vibration and harshness (NVH) performance.
As the automotive industry continues to reinvent itself, new transmission technologies are at the forefront of this effort, and there is a whirlwind of new developments being detailed at the German Car Training Instituteâs Automotive Transmissions and Drive Trains Symposium North America.
This study quantified the performance of a new alloy and has provided guidance for the design and development of next-generation gear steels.
Synopsis on the latest developments at several gear design software developers.
With all the work in transmission development these days, the demand for automobile transmission gears should remain strong for several years, but suppliers will have to be as flexible as possible to keep up with the changes.
The 130SV shaving machine from Gleason is the newest of the company's Genesis family of gear production equipment.
This paper introduces new process developments in low-pressure carburizing and carbonitriding using either high-pressure gas quenching or interrupted gas quenching.
The Forest City Gear booth at Gear Expo featured a wide variety of gears utilized in medical equipment, Indy cars, fishing reels, even the recently launched Mars Rover. Scattered among Forest Cityâs products in Cincinnati were some unique gear sculptures created by an artist that finds more inspiration from the pages of industrial magazines than art galleries.
Material losses and long production times are two areas of conventional spur and helical gear manufacturing in which improvements can be made. Metalforming processes have been considered for manufacturing spur and helical gears, but these are costly due to the development times necessary for each new part design. Through a project funded by the U.S. Army Tank - Automotive Command, Battelle's Columbus Division has developed a technique for designing spur and helical gear forging and extrusion dies using computer aided techniques.
It may not be widely recognized that most of the inspection data supplied by inspection equipment, following the practices of AGMA Standard 2015 and similar standards, are not of elemental accuracy deviations but of some form of composite deviations. This paper demonstrates the validity of this âcompositeâ label by first defining the nature of a true elemental deviation and then, by referring to earlier literature, demonstrating how the common inspection practices for involute, lead (on helical gears), pitch, and, in some cases, total accumulated pitch, constitute composite measurements.
In the field of large power transmission gear units for heavy machine industry, the following two development trends have been highly influential: use of case hardened gears and a branching of the power flow through two or more ways.
The development of a new gear strength computer program based upon the finite element method, provides a better way to calculate stresses in bevel and hypoid gear teeth. The program incorporates tooth surface geometry and axle deflection data to establish a direct relationship between fillet bending stress, subsurface shear stress, and applied gear torque. Using existing software links to other gear analysis programs allows the gear engineer to evaluate the strength performance of existing and new gear designs as a function of tooth contact pattern shape, position and axle deflection characteristics. This approach provides a better understanding of how gears react under load to subtle changes in the appearance of the no load tooth contact pattern.
"Gears of Gold" and "Process Equipment's Virtual ND430."
Much information has been written on gear inspection, analytical. functional. semiautomatic and automatic. In most cases, the charts, (if you are lucky enough to have recording equipment) have been explained.
Since the design of involute splines and their manufacture requires considerable knowledge, not only of the basic properties of the involute profile, but also of various other elements which affect the spline fit and the sometimes complex principles underlying manufacturing and checking equipment, the question is frequently raised as to why the involute profile is given preference in designing splines over the seemingly simpler straight sided tooth profile.
Hobs, broaches, shaper cutters, shaver cutters, milling cutters, and bevel cutters used in the manufacture of gears are commonly made of high speed steel. These specialized gear cutting tools often require properties, such as toughness or manufacturability, that are difficult to achieve with carbide, despite the developments in carbide cutting tools for end mills, milling cutters, and tool inserts.
This paper presents the results of a study performed to measure the change in residual stress that results from the finish grinding of carburized gears. Residual stresses were measured in five gears using the x-ray diffraction equipment in the Large Specimen Residual Stress Facility at Oak Ridge National Laboratory.
When you push 850 horsepower and 9,000 rpm through a racing transmission, you better hope it stands up. Transmission cases and gears strewn all over the racetrack do nothing to enhance your standing, nor that of your transmission supplier.
In the past, the coffee breaks and dinner events at Sigma Poolâs gear seminars have often triggered future process development and product improvements. This was still the case during the 2009 installment where customers and suppliers talked shop inside and outside the banquet hall on the new market and technology challenges currently facing the gear industry.
Beveloid gears are used to accommodate a small shaft angle. The manufacturing technology used for beveloid gearing is a special setup of cylindrical gear cutting and grinding machines. A new development, the so-called Hypoloid gearing, addresses the desire of gear manufacturers for more freedoms. Hypoloid gear sets can realize shaft angles between zero and 20Â° and at the same time, allow a second shaft angle (or an offset) in space that provides the freedom to connect two points in space.
This article shows the newest developments to reduce overall cycle time in grinding wind power gears, including the use of both profile grinding and threaded wheel grinding.
In the August 2008 issue of Gear Technology, we ran a story (âGearbox Speed Reducer Helps Fan Technology for âGreenerâ Jet Fuel Efficiencyâ) on the then ongoing, extremely challenging and protracted development of Pratt & Whitneyâs geared turbofan (GTF) jet engine.
The objective, according to Dr.- Ing. HansjĂ¶rg Geiser, head of development and design for gear machines at Liebherr, was to develop and design a combined turning and hobbing machine in which turning, drilling and hobbing work could be carried out in the same clamping arrangement as the hobbing of the gearings and the subsequent chamfering and deburring processes.
Faithful Addendum readers are accustomed to finding upbeat, whimsical and oddball stories about gears in this space. What follows is not about gears, exactly. Rather, it is, as opposed to the usual bleak news about America losing its manufacturing mojo—a look at a positive, hopeful development in that regard.
What was once recognized as the unique genius of America is now slipping away from us and, in many areas, is now seen as a "second rate" capability. Unless action is taken now, this country is in real danger of being unable to regain its supremacy in technological development and economic vigor. First Americans must understand the serious implications of the problem; and second, we must dedicate ourselves to national and local actions that will ensure a greater scientific and technological literacy in America.
In recent years, gear inspection requirements have changed considerably, but inspection methods have barely kept pace. The gap is especially noticeable in bevel gears, whose geometry has always made testing them a complicated, expensive and time-consuming process. Present roll test methods for determining flank form and quality of gear sets are hardly applicable to bevel gears at all, and the time, expense and sophistication required for coordinate measurement has limited its use to gear development, with only sampling occurring during production.
Increasingly gear designers and product engineers are capitalizing on the economic advantages of powder metallurgy (P/M) for new and existing gear applications. Powder metal gears are found in automobiles, outdoor power equipment transmissions and office machinery applications as well as power hand tools, appliances and medial components.
An engineer's responsibility for verifying a new design or product concept as manufacturable early in the development cycle is a tough challenge. What appears to work on a blueprint or in a three-dimensional CAD file on a computer screen many not work on the factory floor; and the downstream impact on the manufacturing process of an undetected design flaw can be enormous. Costs can run into the millions.
Near-net gear forging today is producing longer life gears at significantly lower costs than traditional manufacturing techniques. Advances in forging equipment, controls and die-making capability have been combined to produce commercially viable near-net-shape gears in diameters up to 17" with minimum stock allowances. These forged gears require only minimal finishing to meet part tolerance specifications.
A research program, conducted in conjunction with a U.S. Army contract, has resulted in the development of manufacturing technology to produce a multi-metal composite gear/shaft representing a substantial weight savings compared to a solid steel component. Inertia welding is used to join a steel outer ring to a light-weight titanium alloy web and/or shaft through the use of a suitable interlayer material such as aluminum.
NC and CNC machines are at the heart of manufacturing today. They are the state-of-the-art equipment everybody has (or is soon going to get) that promise to lower costs, increase production and turn manufacturers into competitive powerhouses. Like many other high tech devices (such as microwaves and VCRs), lots of people have and use them - even successfully - without really knowing much about how they operate. But upgrading to CNC costs a lot of money, so it's crucial to separate the hype from the reality.
Most steel gear applications require appreciable loads to be applied that will result in high bending and compressive stresses. For the material (steel) to meet these performance criteria, the gear must be heat treated. Associated with this thermal processing is distortion. To control the distortion and achieve repeatable dimensional tolerances, the gear will be constrained during the quenching cycle of the heat treatment process. This type of fixture quenching is the function of gear quench pressing equipment.
Gear Expo '93 - another trade show, another plea to send people and/or equipment out of town, away from the office or plant. Another bid to spend time, money, and effort. Oh, please! Hasn't anybody heard that these are the "lean and mean" '90s?
Could the tip chamfer that manufacturing people usually use on the tips of gear teeth be the cause of vibration in the gear set? The set in question is spur, of 2.25 DP, with 20 degrees pressure angle. The pinion has 14 teeth and the mating gear, 63 teeth. The pinion turns at 535 rpm maximum. Could a chamfer a little over 1/64" cause a vibration problem?
One of the key questions to be answered when exporting is how you are going to get your product to your customer. All the time, effort, and money you've spent to make a sale in the first place can be wasted if the shipment is late, damaged, or lost, or if delivery becomes an expensive bureaucratic nightmare for either you or the buyer.
Today's high technology hobs are visible different from their predecessors. Gear hobs have taken on a different appearance and function with present day technology and tool and material development. This article shows the newer products being offered today and the reasons for investigating their potential for use in today's modern gear hobbers, where cost reduction and higher productivity are wanted.
8 Gear Technology advertisers will have booths at IMTS 92, the largest trade show in the Western Hemisphere. The show opens in Chicago on Sept. 9 and runs through the 17th. More than 800 companies from around the world will cover some 931,000 sq. ft. of exhibit space to show the latest manufacturing technology - everything from forming and fabrication products to environmental and plant safety equipment.
This past fall, I had the opportunity to travel to Japan, Korea, Taiwan, and Singapore to witness first-hand the status of the power transmission and machine tool industries in these areas. Points of interest included equipment, material handling, computerization, wage and tax structures, inventory controls, and workforce attitude.
Spur gear endurance tests were conducted to investigate the surface pitting fatigue life of noninvolute gears with low numbers of teeth and low contact ratios for the use in advanced application. The results were compared with those for a standard involute design with a low number of teeth. The gear pitch diameter was 8.89 cm (3.50 in.) with 12 teeth on both gear designs. Test conditions were an oil inlet temperature of 320 K (116 degrees F), a maximum Hertz stress of 1.49 GPa (216 ksi), and a speed of 10,000 rpm. The following results were obtained: The noninvolute gear had a surface pitting fatigue life approximately 1.6 times that of the standard involute gear of a similar design. The surface pitting fatigue life of the 3.43-pitch AISI 8620 noninvolute gear was approximately equal to the surface pitting fatigue life of an 8-pitch, 28-tooth AISI 9310 gear at the same load, but at a considerably higher maximum Hertz stress.
CTI Symposium Presents Latest Automotive Transmission Developments and Applications.
Carburized and hardened gears have optimum load-carrying capability. There are many alternative ways to produce a hard case on the gear surface. Also, selective direct hardening has some advantages in its ability to be used in the production line, and it is claimed that performance results equivalent to a carburized gear can be obtained. This article examines the alternative ways of carburizing, nitriding, and selective direct hardening, considering equipment, comparative costs, and other factors. The objective must be to obtain the desired quality at the lowest cost.
The art of gear hobbing has advanced dramatically since the development and introduction of unique machine and tool features such as no backlash, super rigidity, automatic loading of cutting tools, CNC controls, additional machine power and improved cutter materials and coatings. It is essential to utilize all these features to run the machine economically.
Worm gearing is of great antiquity, going back about 2100 years to Archimedes, who is generally acknowledged as its inventor. Archimedes' concept used an Archimedial spiral to rotate a toothed wheel. Development of the worm gearing principle progressed along conventional lines until about 500 years ago when Leonardo DaVinci evolved the double enveloping gear concept.
Curvic Couplings were first introduced in 1942 to meet the need for permanent couplings and releasing couplings (clutches), requiring extreme accuracy and maximum load carrying capacity, together with a fast rate of production. The development of the Curvic Coupling stems directly from the manufacture of Zerol and spiral bevel gears since it is made on basically similar machines and also uses similar production methods. The Curvic Coupling can therefore lay claim to the same production advantages and high precision associated with bevel gears.
A change has taken place within the industry that is going to have an enormous effect on the marketing, sales, and purchasing of gear manufacturing and related equipment. This change was the American Gear Manufacturers' Association, first biennial combination technical conference and machine tool minishow.
As Gear Technology moves toward its third anniversary, we feel that we have reached a point in our development where it is time to pause, reflect on our accomplishments and plan for the future.
Noisy gear trains have been a common problem for gear designers for a long time. With the demands for smaller gear boxes transmitting more power at higher rpms and incumbent demands for greater efficiency, gear engineers are always searching for new ways to reduce vibration and limit noise without increasing costs.
The last decade has been a period of far-reaching change for the metal working industry. The effect of higher lubricant costs, technical advances in machine design and increasing competition are making it essential that manufacturers of gears pay more attention to testing, selecting and controlling cutting fluid systems. Lubricant costs are not a large percentage of the process cost relative to items such as raw materials, equipment and labor, and this small relative cost has tended to reduce the economic incentive to evaluate and to change cutting fluids.
Hard Gear Finishing (HGF), a relatively new technology, represents an advance in gear process engineering. The use of Computer Numerical Controlled (CNC) equipment ensures a high precision synchronous relationship between the tool spindle and the work spindle as well as other motions, thereby eliminating the need for gear trains. A hard gear finishing machine eliminates problems encountered in two conventional methods - gear shaving, which cannot completely correct gear errors in gear teeth, and gear rolling, which lacks the ability to remove stock and also drives the workpiece without a geared relationship to the master rolling gear. Such a machine provides greater accuracy, reducing the need for conventional gear crowning, which results in gears of greater face width than necessary.
Beginning with our next issue, some of the promised changes in format for Gear Technology will begin showing up in these pages. As part of our commitment to provide you with important information about the gear and gear products industry, we are expanding our coverage. In addition to continuing to publish some of the best results of gear research and development throughout the world, we will be adding special columns covering vital aspects of the gearing business.
The concept of "transmission error" is relatively new and stems from research work in the late 1950s by Gregory, Harris and Munro,(1) together with the need to check the accuracy of gear cutting machines. The corresponding commercial "single flank" testing equipment became available in the 1960s, but it was not until about ten years ago that it became generally used, and only recently has it been possible to test reliably at full load and full speed.
Spur gear surface endurance tests were conducted to investigate CBN ground AISI 9310 spur gears for use in aircraft applications, to determine their endurance characteristics and to compare the results with the endurance of standard vitreous ground AISI 9310 spur gears. Tests were conducted with VIM-VAR AISI 9210 carburized and hardened gears that were finish ground with either CBN or vitreous grinding methods. Test conditions were an inlet oil temperature of 320 K (116 degree F), an outlet oil temperature of 350 K (170 degree F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. The CBN ground gears exhibited a surface fatigue life that was slightly better than the vitreous ground gears. The subsurface residual stress of the CBN ground gears was approximately the same as that for the standard vitreous ground gears for the CBN grinding method used.
Traditional methods of manufacturing precision gears usually employ either hobbing or shaper cutting. Both of these processes rely upon generating the conjugate tooth form by moving the work-piece in a precise relation to the tool. Recently, attention has been given to forming gear teeth in a single step. Advantages to such a process include reduced production time, material savings, and improved performance characteristics. Drawbacks include complicated tool designs, non-uniformity of gears produced throughout the life of the tooling, and lengthy development times.
An accurate and fast calculation method is developed to determine the value of a trigonometric function if the value of another trigonometric function is given. Some examples of conversion procedures for well-known functions in gear geometry are presented, with data for accuracy and computing time. For the development of such procedures the complete text of a computer program is included.
When manufacturing powder metal (PM) gears lead crowning is not achievable in the compaction process. This has to be accomplished either by shaving, grinding or honing. Each of these processes has their merits and draw backs. When employing rolling using a roll burnishing machine lead crowning can be accomplished but due to errors in profile a hard finishing operation such as grinding is used by the industry. In this paper a helical PM gear that has sufficient tolerance class after rolling has been tested in a test rig for durability and the wear has been studied.
Despite economic uncertainty, the future looks promising for PM Gears.
Decades ago, technology shifted from HSS to indexable inserts in turning and milling. This movement wasn't immediately realized in gear hobbing because coated PM-HSS hobs and complex gear profiles remained highly effective and productive methods. Only fairly recently have gear manufacturers started to take a serious look at indexable technology to cut gear teeth.
This is part II of a two-part paper that presents the results of extensive test programs on the RCF strength of PM steels.
This article summarizes results of research programs on RCF strength of wrought steels and PM steels.
News Items About pm
1 Process Equipment Announces Partnerships (August 30, 2007)
Process Equipment Announces PartnershipsProcess Equipment Co. announced a distributorship agreement with Arthur Klick Co. for distributio... Read News
2 Romax Improves Driveline Design and Development (May 15, 2013)
Romax Technology is enabling a rapid, seamless and lossless workflow for driveline design and development from planning to manufacture. T... Read News
3 Sensor Development's Latest Model Measures Small Reaction Torque Level (August 6, 2007)
The Model 01165 small flange reaction torque sensor from Sensor Development is designed to measure small reaction torqu levels using flan... Read News
4 Sandvik Supports the Hurco Chipmaker Challenge (August 1, 2014)
Hurco announced today that Sandvik Coromant will donate $1,000 worth of tooling to the champion of the Chipmaker Challenge, a contest des... Read News
5 Romax Appoints Business Development Manager for Hybrid Technology (June 15, 2010)
Romax Technology recently recruited a new business development manager to manage Romax's hybrid and electric vehicle consultancy.&nbs... Read News
6 Drake Hires Product Development Engineer (August 8, 2013)
Drake Manufacturing Services Co. has recently hired Olguta Marinescu as a product development engineer. She has a B.S. in Electrical Engi... Read News
7 DT-1 Drill/Tap Center from Haas Allows Rigid Tapping to 5,000 RPM (June 16, 2015)
The DT-1 Drill/Tap center from Haas Automation, Inc., is now available with a 20,000-rpm inline direct-drive spindle, giving customers th... Read News
8 Forest City Gear Invests in Capital Equipment (February 12, 2009)
Forest City Gear has announced it has invested more than $6 million in the purchase of new capital equipment during the last 18 months. T... Read News
9 Heimatec 1:4 Live Tool Speed Multiplier Available in Styles up to 24,000 RPM (March 30, 2016)
Heimatec has announced that its newest development, a line of 1:4 live tool speed multipliers in 24,000 RPM max. styles, is now available... Read News
10 Delta College Receives CNC Equipment Entrustments (March 31, 2016)
Delta College recently received several large entrustments of equipment from leading manufacturers, allowing them to upgrade their CNC fa... Read News
11 IMS Research Analyzes Geared Product Shipments (December 27, 2012)
Shipments of precision geared products (gearboxes and geared motors with backlash ratings of less than 20 arcminutes) were nearly 80 perc... Read News
12 Northstar Aerospace Receives Contract for New Drive System Development (August 30, 2007)
Northstar Aerospace was awarded a $4.5 million development contract from The Boeing Co. for its Enhanced Rotor Rotorcraft Drive System (E... Read News
13 Ipsen Adds Janusz Kowalewski as Director of Business Development for ARGOS (August 1, 2016)
Ipsen is pleased to announce that Janusz Kowalewski joined the Ipsen Team as Director of Business Development for ARGOS. Kowalewski holds... Read News
14 Houghton International Fluid Equipment Solutions Add Control Options for Water-Based Metal Cutting (August 12, 2016)
Houghton International has launched two new fluid equipment solutions that provide manufacturers with significantly greater control of fl... Read News
15 Schafer Gear Adds New Grinding Equipment (May 24, 2007)
Schafer Gear Works invested in new production equipment, including new gear grinding machines in the company's South Bend, IN, and Ro... Read News
16 Philadelphia Gear Offers Two Versions of Continuous Oil Rescue Equipment (March 5, 2007)
Philadelphia Gear Corp. announced the availability of two versions of the company's proprietary CORE Continuous Oil Rescue Equipment.... Read News
17 Cleaning Technologies Group Releases Planning for New Cleaning Equipment Guide for Free (January 2, 2018)
Cleaning Technologies Group is excited to announce the release of their new guide, "Planning for New Cleaning Equipment." The a... Read News
18 Wall Colmonoy Appoints Business Development Manager (April 17, 2006)
Morris Warino was appointed business development manager for Wall Colmonoy Corp. of Oklahoma City, OK. According to the companys... Read News
19 MPIF Redesigns PickPM Website (March 7, 2017)
The Metal Powder Industries Federation's (MPIF) Industry Development Board (IDB) has completed a redesign of the PickPM.com website. ... Read News
20 Siemens Announces Lifelong Educational Advantage Program for Workforce Development in Secondary and Technical Schools (March 8, 2017)
Siemens announced the launch of a new workforce development program for secondary and technical schools across America called LEAP - the ... Read News
21 Process Equipment Sold, President Retires (April 24, 2005)
Larry Ewald announced his retirement after 27 years at Process Equipment Co. In 1978, he succeeded the company's founder, Emmert Stud... Read News
22 Seco/Warwick Relocates Operations to Production, Assembly and Test Equipment Facility in India (February 2, 2017)
To better serve its customer base in India, Seco/Warwick has relocated its operations to a new production, assembly and test equipment fa... Read News
23 Process Equipment Sold, President Retires (April 19, 2005)
Larry Ewald announced his retirement after 27 years at Process Equipment Co. In 1978, he succeeded the companys founder, Emmert Stu... Read News
24 Cowley Hired as Sales Manager of Process Equipment (April 12, 2005)
Bruce Cowley was hired as sales manager for the metrology systems division of Process Equipment Co. According to the company's p... Read News
25 Recent Developments at Ikona Gear (February 21, 2005)
Ikona Gear has entered into a developmental agreement with StarRotor Corp. to provide patented Ikona technology for the third generation ... Read News
26 Nevada Heat Treating Invests in New Equipment (April 4, 2011)
Nevada Heat Treating has recently placed orders for two new advanced heat treating furnaces. This represents a capital investment of appr... Read News
27 PMA Predicts Business to Improve (February 20, 2012)
According to the February 2012 Precision Metalforming Association (PMA) Business Conditions Report, metalforming companies predict a spik... Read News
28 PMAEF Issues Awards to Metalforming Industry (February 22, 2011)
The PMA Educational Foundation (PMAEF) has received a grant from The Hitachi Foundation to launch a new project searching for and profili... Read News
29 NTMA & PMA Support Currency Legislation (October 13, 2011)
The National Tooling & Machining Association (NTMA) and the Precision Metalforming Association (PMA) issued the following statement o... Read News
30 Minera Re-Sizes Metso's Equipment for Mining Project (June 22, 2011)
Minera Panama S.A. has revised the original 2008 purchase of Metso grinding mills for the Cobre Panama project and has confirmed the resi... Read News
31 PMA to Host Inaugural Women in Manufacturing Symposium (September 16, 2011)
More than 150 women executives, managers and supervisors will gather in Cleveland, Ohio, on October 25-26, 2011 for the first annual Wome... Read News
32 Hole Specialists Add Equipment Before Expansion Project (December 16, 2011)
Everything is bigger in Texas, and come February 2012, Tomball-based Hole Specialists will be bigger after it moves into a 25,800 sq. ft.... Read News
33 Gear Applications Discussed at Euro PM 2011 (December 6, 2011)
Gear applications have emerged as an important target for the PM structural parts sector and several of the leading PM groups have develo... Read News
34 PMA Elects New Leaders (January 26, 2011)
The Precision Metalforming Association (PMA) recently announced the election of Augusto Gil (pictured right) to the position of Metal Spi... Read News
35 PMA Anticipates Continued Improvement (February 16, 2011)
According to the February 2011 Precision Metalforming Association (PMA) Business Conditions Report, metalforming companies anticipate con... Read News
36 AMSC Partners with Shenyang Blower Works for Turbine Development (November 24, 2008)
American Superconductor Corporation (AMSC) recently signed an agreement with Shenyang Blower Works Co., Ltd. to co-develop wind turbine... Read News
37 PMA Business Report for December Optimistic (December 15, 2010)
According to the December 2010 Precision Metalforming Association (PMA) Business Conditions Report, metalforming companies anticipate a s... Read News
38 Abstracts for PM2010 World Congress Now Available (June 16, 2010)
The PM2010 World Congress taking place in Florence, Italy from October 10-15 features a number of technical sessions devoted to MIM and C... Read News
39 NTMA & PMA Issue Statement on Small Business Lending (May 25, 2010)
The National Tooling and Machining Association (NTMA) and the Precision Metalforming Association (PMA) issued the following statement in ... Read News
40 PM Touches Your Life DVD Released (January 27, 2010)
Powder Metallurgy: The Preferred Metal-Forming Solution, a new video showcasing the fabrication capabilities of the various technologies ... Read News
41 Halifax Rack and Screw Invests in New Equipment (August 25, 2009)
The Cincinnati North America distribution center for Halifax Rack and Screw Cutting Company of Cincinnati, OH and Brighouse, England has... Read News
42 FMS Awarded for Outstanding PM Part (August 19, 2009)
The Metal Powder Industries Federation (MPIF) presented FMS Corporation with the Outstanding Powder Metallurgy Parts Grand Prize in the l... Read News
43 PM Association Names President (April 2, 2009)
Richard Pfingstler, president of Atlas Pressed Metals in DuBois, PA, has been appointed president of the Powder Metallurgy Parts Associat... Read News
44 FMS Wins PM Award (July 26, 2012)
FMS Corporation, Minneapolis, Minnesota, won the grand prize in the lawn & garden/off-highway category for a PM steel gear race used ... Read News
45 Outstanding PM Parts Awarded (July 24, 2008)
The 2008 Powder Metallurgy Design Excellence Awards Competition took place at the PM2008 World Congress in June. Several of the winning ... Read News
46 PMA Reports Business Conditions Steady in January 2008 (February 14, 2008)
According to the January 2008 Precision Metalforming Association (PMA) Business Conditions Report, metalforming companies expect business... Read News
47 GM, BMW and DaimlerChrysler Announce $1 Billion Hybrid Transmission Development Program (April 15, 2006)
A research alliance consisting of GM, BMW and DaimlerChrysler plans to invest more than $1 billion to develop a new hybrid transmission t... Read News
48 Donner + Pfister Introduces New Measuring Equipment (January 19, 2005)
The ES 4100 portable pitch measuring instrument from Donner + Pfister offers measuring data. Operational convenience is achieved by the b... Read News
49 PMA Releases Business Conditions Report (May 21, 2012)
According to the May 2012 Precision Metalforming Association (PMA) Business Conditions Report, metalforming companies expect a softening ... Read News
50 Specialty Steel Invests in AFC-Holcroft Equipment (April 17, 2019)
Commercial heat treater Specialty Steel Treating in Fraser, Michigan (USA) has invested in new AFC-Holcroft UBQ (Universal Batch Quench) ... Read News
51 PMA Introduce Series of Programs Highlighting Servo Press Technology (August 9, 2012)
The Precision Metalforming Association's (PMA) flagship publication, MetalForming magazine, announces a series of new technical progr... Read News
52 Mahr Custom RPM Gage Designed for Dynamic Measurement of Cylindrical Parts (January 31, 2017)
The MarSolutions team at Mahr Federal has developed a customized RPM gage for the dynamic measurement of cylindrical parts such as commut... Read News
53 Governor Charles D. Baker Visits Adcole to Recognize Product Development (September 2, 2015)
Governor Charles D. Baker, Jr. recently visited Adcole Corporation and was accompanied by Jay Ash, secretary of housing and economic deve... Read News
54 Maynards to Auction Surplus Equipment from Abundant Manufacturing, Inc. (April 14, 2016)
Plans are now gearing up for an auction of surplus assets from Abundant Manufacturing, Inc. and RP Machine Enterprises, Inc. This top qua... Read News
55 R&P Metrology Installs Large Mobile Inspection Equipment (May 3, 2016)
R&P Metrology GmbH has announced it has recently installed two very large portable measuring machines, one in Asia and one in Europe.... Read News
56 APMI Announces 2016 Fellow Award Recipients (June 27, 2016)
APMI International, the professional society for powder metallurgy, has named Hideshi Miura, professor, Kyushu University, Fukuoka, Japan... Read News
57 Joe Gentile Named to PMPA Technical Board (December 7, 2016)
Joe Gentile, Product Manager for Hangsterfer's Laboratories of Mantua, N.J. was named First Vice-Chair of the Technical Members Board... Read News
58 Advanced Materials Development Corp. Offers New Material Options for Automotive Components (January 18, 2017)
Car and truck manufacturers are faced with the difficult task of significantly improving fuel economy while maintaining safety and compet... Read News
59 Controx-Neuhauser Saw Blades and Side Milling Cutters On Display at PMTS (February 24, 2017)
Controx-Neuhauser is presenting a full line of standard saw blades and side chip clearance saws suitable for a wide range of precision cu... Read News
60 U.S. Speed Changer, Industrial High-Speed Drive, and Gear Manufacturing Industry Shipment (June 12, 2015)
This latest Speed Changer, Industrial High-Speed Drive, and Gear Manufacturing Industry report provides the most updated market research ... Read News
61 Exsys Tool Offers Innovations at PMTS 2017 (March 3, 2017)
Several innovative tooling, rotary table and gear making solutions will take center stage at PMTS 2017 on April 25-27 to be held at the G... Read News
62 Siemens Commits to American Manufacturing and Workforce Development (March 30, 2017)
Siemens Joe Kaeser, president and CEO of Siemens AG, bolstered Siemens' strong commitment to strengthening American manufacturing dur... Read News
63 Mahr Federal Depth Gaging Equipment Provide Wireless Data Transmission to Expedite Measurement Process (May 31, 2017)
Mahr Federal expands its line of wireless gaging products to include a range of depth gaging products. Digital Depth Gage MarCal 30 EWR, ... Read News
64 APMI Announces 2017 Fellow Award Recipients (July 6, 2017)
APMI International's most prestigious award recognizes APMI members for their significant contributions to the goals, purpose, and mi... Read News
65 Ipsen Offers Credit Toward New Heat Treating Equipment (August 14, 2017)
Ipsen believes that one of the most valuable things a company can do is invest in others. They are also committed to advancing the heat-t... Read News
66 PMA Announces 2017 Awards of Excellence in Metalforming (November 16, 2017)
The Precision Metalforming Association (PMA) has announced the winners of its 2017 Awards of Excellence in Metalforming. Presented annual... Read News
67 Hoganas AB Showcases PM at CTI Symposium (November 27, 2017)
Höganäs AB will showcase its range of sustainable metal powder solutions for future powertrains at CTI Symposium and Transmissi... Read News
68 Schunk Tendo Platinum Toolholder Balanced to G2.5 at 25,000 RPM (July 14, 2015)
Schunk recently introduced the new Tendo Platinum toolholder. Tendo Platinum offers improved brazing technology by using a brazing and ha... Read News
69 FPM Heat Treating Receives Nadcap Accreditation (April 20, 2015)
FPM Heat Treating in Elk Grove Village, IL announced that it has received an additional Nadcap Scope of Accreditation for carburizing, c... Read News
70 PMA Business Conditions Improve (August 20, 2012)
According to the August 2012 Precision Metalforming Association (PMA) Business Conditions Report, metalforming companies expect a slight ... Read News
71 Vomat Equipment Reduces Coolant Costs (October 10, 2013)
Demanding grinding applications require powerful filtration systems that have a poitive effect on the entire production process. The Micr... Read News
72 PTG Appoints Group Business Development Director (October 2, 2012)
Precision Technologies Group (PTG), the U.K.-based specialists in high-precision machine tool and component design, build and supply, hav... Read News
73 The Manufacturing Institute Partners with PMPA on Machine Training Program (October 11, 2012)
The Manufacturing Institute has partnered with the Precision Machined Products Association, Right Skills Now, a fast-track machining trai... Read News
74 Mazak to Exhibit at PMTS 2013 (February 18, 2013)
Mazak will spotlight two small-footprint machines that are big on providing precision, productivity and profitability to shops across all... Read News
75 Modern Heat Treat Expands Production Capability with AFC Holcroft Equipment (March 18, 2019)
In support of its continued growth, Modern Heat Treat, a commercial heat treating operation located in Richland Hills, Texas (USA), has a... Read News
76 PM2014 Call for Papers (August 26, 2013)
The program committee for the 2014 World Congress on Powder Metallurgy & Particulate Materials (PM2014) has issued a “Call for ... Read News
77 Hardinge Offers Latest Workholding Equipment (September 26, 2013)
When it comes to tool holding, value is all about precision and reliability that will transmit to the finished part. Hardinge toolholde... Read News
78 PMA Announces Awards of Excellence in Metalforming (November 25, 2013)
The Precision Metalforming Association (PMA) has announced the winners of its 2013 Awards of Excellence in Metalforming. Presented ... Read News
79 Paulo Selects AFC-Holcroft Equipment for Production Expansion (April 16, 2015)
Paulo, a commercial heat treater headquartered in St. Louis, MO, USA, recently purchased two new Universal Batch Quench (UBQ) furnaces fr... Read News
80 5ME Delivers Machining Fluids for Aerospace and Heavy Equipment (February 14, 2014)
5ME's Cyclo Cool 900 series synthetic metal machining fluids utilize a unique, near-neutral pH formula developed to meet heavy-duty, ... Read News
81 PMA Releases February Business Conditions Report (February 17, 2014)
According to the February 2014 Precision Metalforming Association (PMA) Business Conditions Report, metalforming companies expect a dip i... Read News
82 PMA Accepts Entries for 2014 Awards of Excellence in Metalforming (March 20, 2014)
The Precision Metalforming Association (PMA) invites industry-leading companies to submit an entry for its 2014 Awards of Excellence in Metalforming... Read News
83 Höganäs Updates PM Handbooks (May 6, 2014)
Three of the Höganäs Handbooks have been updated and are now available in the download section on the website. The three handbooks... Read News
84 MPIF Celebrates 50 Years of PM Design (August 12, 2014)
An event that took place without much fanfare at the 1965 International Powder Metallurgy Conference held at New York’s Statler Hil... Read News
85 2015 Call for Presentations for AMPM 2015 (September 22, 2014)
A "Call for Presentations" is being issued to solicit contributions for the technical program for AMPM2015, the Additive Manufa... Read News
86 Index to Demonstrate Modular Eight-spindle Automatic CNC Turning Machine at PMTS 2015 (March 6, 2015)
Index will demonstrate its MS22C-8, a modular eight-spindle automatic CNC turning machine, producing brass connector parts at PMTS 2015, ... Read News
87 United Gear Installs New Inspection Equipment (December 16, 2003)
United Gear & Inspection has installed a new M&M Precision gear inspection machine to double its manufacturing capacity. According to ... Read News