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Articles About CTI Symposium USA


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1 Transmission Throwdown (May 2017)

Which transmission system will come out on top is a hot topic in the automotive community. With multiple transmission-centric conferences on the horizon, there will be plenty of debate, but how much will the answer actually affect gear manufacturers, and when?

2 CTI Symposium USA 2019 (May 2019)

The Past, Present and Future of Vehicle Electrification

3 My Glass is Half Full (October 2012)

Publisher Michael Goldstein is confident that the manufacturing economy will continue to grow throughout next year, no matter who wins the 2012 presidential election.

4 Performance Analysis of Hypoid Gears by Tooth Flank Form Measurement (July/August 2002)

The traditional way of controlling the quality of hypoid gears' tooth flank form is to check the tooth flank contact patterns. But it is not easy to exactly judge the tooth flank form quality by the contact pattern. In recent years, it has become possible to accurately measure the tooth flank form of hypoid gears by the point-to-point measuring method and the scanning measuring method. But the uses of measured data of the tooth flank form for hypoid gears have not yet been well developed in comparison with cylindrical involute gears. In this paper, the tooth flank form measurement of generated face-milled gears, face-hobbed gears and formulate/generated gears are reported. The authors discuss the advantages and disadvantages of scanning and point-to-point measuring of 3-D tooth flank forms of hypoid gears and introduce some examples of uses of measured data for high-quality production and performance prediction.

5 Carburizing of Big Module and Large Diameter Gears (September/October 2002)

Carburized gears have higher strengths and longer lives compared with induction-hardened or quench-tempered gears. But in big module gears, carburizing heat-treatment becomes time-consuming and expensive and sometimes cannot achieve good hardness due to the big mass-effect. Also, it is not easy to reduce distortion of gears during heat treatment.

6 Measuring Profile and Base Pitch Error with a Micrometer (September/October 2002)

In this article, equations for finding profile and base pitch errors with a micrometer are derived. Limitations of micrometers with disc anvils are described. The design of a micrometer with suitable anvils is outlined.

7 The Barkhausen Noise Inspection Method for Detecting Grinding Damage in Gears (November/December 2002)

When hardened steel components are ground, there is always the possibility of damage to the steel in the form of residual stress or microstructural changes. Methods for detecting this sort of damage have always had one or more drawbacks, such as cost, time, complexity, subjectivity, or the use of hazardous chemicals.

8 Engineered Gear Steels: A Review (November/December 2002)

The selection of the proper steel for a given gear application is dependent on many factors. This paper discusses the many aspects related to material, design, manufacture, and application variables. The results of several studies on the optimization of alloy design for gas- and plasma- carburization processing and reviewed.

9 Local 3-D Flank Form Optimizations for Bevel Gears (September/October 2003)

Optimizing the running behavior of bevel and hypoid gears means improving both noise behavior and load carrying capacity. Since load deflections change the relative position of pinion and ring gear, the position of the contact pattern will depend on the torque. Different contact positions require local 3-D flank form optimizations for improving a gear set.

10 America Needs a Different Kind of Candidate (September 2012)

The two candidates in the upcoming presidential election offer two distinctly different approaches to solving America’s economic problems -- neither of which is likely to be successful

11 IMTS 2012 Product Preview (September 2012)

Previews of manufacturing technology related to gears that will be on display at IMTS 2012.

12 The Results Are In (November/December 2012)

The past several months have been filled with uncertainty. Everyone wanted to wait and see who would be our next president and how the political landscape might change. Now the elections are over, and the polls are all closed, so we should all be getting back to business, right? Publisher Michael Goldstein shares insight from our state-of-the-gear-industry survey.

13 Measuring Base Helix Error on a Sine Bar (July/August 2001)

Base helix error - the resultant of lead and profile errors is the measured deviation from the theoretical line of contact (Fig. 1). It can be measured in the same way that lead error on a spur gear is measured, namely, by setting a height gage to height H based on the radial distance r to a specified line of contact (Fig. 2), rotating the gear so as to bring a tooth into contact with the indicator on the height gage, and then moving the height gage along two or more normals to the plane of action. The theoretical line of contact on helical gear must be parallel to the surface plate, which is attained by mounting the gear on a sine bar (Fig. 3).

14 CMM Gear Inspection (January/February 2013)

Mitutoyo offers capable, affordable and flexible gear inspection option via coordinate measuring machines and gear inspection software.

15 Do No Destructive Testing (January/February 2013)

An overview of nondestructive testing and its importance in the manufacture of big gears.

16 Measurement of Involute Master (January/February 2013)

Our experts tackle the topic of measuring involute masters, including both master gears and gear inspection artifacts.

17 Gear Material Selection and Construction for Large Gears (January/February 2013)

A road map is presented listing critical considerations and optimal use of materials and methods in the construction of large gears.

18 Large Pinions for Open Gears - The Increase of Single Mesh Load (January/February 2013)

This paper introduces mandatory improvements in design, manufacturing and inspection - from material elaboration to final machining - with special focus on today's large and powerful gearing.

19 Recent Inventions and Innovations in Induction Hardening of Gears and Gear-Like Components (March/April 2013)

This paper examines the expanding capabilities of induction hardening of gears through methods like spin hardening or tooth-by-tooth techniques.

20 Off-Highway Gears (June/July 2013)

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.

21 Liebherr Touts Technology at Latest Gear Seminar (June/July 2013)

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.

22 Leading the Way in Lead Crown Correction and Inspection (August 2013)

Forest City Gear applies advanced gear shaping and inspection technologies to help solve difficult lead crown correction challenges half a world away. But these solutions can also benefit customers much closer to home, the company says. Here's how…

23 Turbine Gearbox Inspection - Steady Work in a Shaky Wind Market (August 2013)

Having outlasted the worldwide Great Recession, the Global Wind Energy Council (GWEC) forecasts a constant growth in wind energy, i.e.: "increase in worldwide capacity to 460,000 MW by 2015."

24 What "Ease-Off" shows about Bevel and Hypoid Gears (September/October 2001)

The configuration of flank corrections on bevel gears is subject to relatively narrow restrictions. As far as the gear set is concerned, the requirement is for the greatest possible contact zone to minimize flank compression. However, sufficient reserves in tooth depth and longitudinal direction for tooth contact displacement should be present. From the machine - and particularly from the tool - point of view, there are restrictions as to the type and magnitude of crowning that can be realized. Crowning is a circular correction. Different kinds of crowning are distinguished by their direction. Length crowning, for example, is a circular (or 2nd order) material removal, starting at a reference point and extending in tooth length or face width.

25 Inspection Focus News & Technology (July/August 2000)

This section is dedicated to what's new and what's happening in the world of gear inspection and metrology. Here you will find news about products, companies and organizations, services and events affecting the gear inspection and metrology industry.

26 The Submerged Induction Hardening of Gears (March/April 2001)

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.

27 Automated Inspection Systems: The Whole Picture (January/February 1998)

No one (not even you and I) consistently makes parts with perfect form and dimensions, so we must be able to efficiently check size and shape at many stages in the manufacturing and assembly process to eliminate scrap and rework and improve processes and profits. Automated inspection systems, which are widely used in all kinds of manufacturing operations, provide great efficiencies in checking individual features, but may not be as effective when asked to evaluate an entire part. You need to know why this is true and what you can do to improve your part yields.

28 The Politics of Denial (September/October 1996)

A good many things bother me about election years - the annoying sound bites, the negative commercials, the endless political over-analysis. But what bothers me most about the coming election is this: So far (when I'm writing this, it's admittedly early in the campaign) there's little or no talk about what is one of the most critical national issues of the next thirty years - our growing government debt.

29 Powder Metal Gear Design and Inspection (September/October 1996)

Powder metallurgy (P/M) is a precision metal forming technology for the manufacture of parts to net or near-net shape, and it is particularly well-suited to the production of gears. Spur, bevel and helical gears all may be made by made by powder metallurgy processing.

30 Induction Heat Trating: Things Remembered, Things Forgotten (March/April 1997)

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.

31 Eddy Current Examination of Gear Systems (May/June 1997)

Nondestructive examination (NDE) of ferrous and nonferrous materials has long proved an effective maintenance and anomaly characterization tool for many industries. Recent research has expanded its applicability to include the inspection of large, open gear drives. Difficulties inherent in other NDE methods make them time-consuming and labor-intensive. They also present the user with the environmental problem of the disposal of used oil. The eddy current method addresses these problems.

32 M & M Precision, Penn State & NIST Team Up For Gear Metrology Research (July/August 1997)

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.

33 Involute Inspection Methods and Interpretation of Inspection Results (July/August 1997)

What is so unique about gear manufacturing and inspection? Machining is mostly associated with making either flat or cylindrical shapes. These shapes can be created by a machine's simple linear or circular movements, but an involute curve is neither a straight line nor a circle. In fact, each point of the involute curve has a different radius and center of curvature. Is it necessary to go beyond simple circular and linear machine movements in order to create an involute curve? One of the unique features of the involute is the fact that it can be generated by linking circular and linear movements. This uniqueness has become fertile soil for many inventions that have simplified gear manufacturing and inspection. As is the case with gear generating machines, the traditional involute inspection machines take advantage of some of the involute properties. Even today, when computers can synchronize axes for creating any curve, taking advantage of involute properties can be very helpful. I t can simplify synchronization of machine movements and reduce the number of variables to monitor.

34 Obtaining Meaningful Surface Roughness Measurements on Gear Teeth (July/August 1997)

Surface roughness measuring of gear teeth can be a very frustrating experience. Measuring results often do not correlate with any functional characteristic, and many users think that they need not bother measuring surface roughness, since the teeth are burnished in operation. They mistakenly believe that the roughness disappears in a short amount of time. This is a myth! The surface indeed is shiny, but it still has considerable roughness. In fact, tests indicate that burnishing only reduces the initial roughness by approximately 25%.

35 Worm Gear Measurement (September/October 1997)

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.

36 Thermal Effects on CMMs (September/October 1997)

The trend toward moving coordinate measuring machines to the shop floor to become an integral part of the manufacturing operations brings real time process control within the reach of many companies. Putting measuring machines on the shop floor, however, subjects them to harsh environmental conditions. Like any measuring system, CMMs are sensitive to any ambient condition that deviates from the "perfect" conditions of the metrology lab.

37 Gear Teeth With Byte (January/February 1998)

Computers are everywhere. It's gotten so that it's hard to find an employee who isn't using one in the course of his or her day - whether he be CEO or salesman, engineer or machinist. Everywhere you look, you find the familiar neutral-colored boxes and bright glowing screens. And despite the gear industry's traditional reluctance to embrace new technology, more and moe of what you find on those screens are gears.

38 New Standards for Large Ring Gears for Mills, Kilns (September 2013)

Methods of examining large ring gear teeth to detect surface breaking discontinuities have often been time-consuming and limited in terms of data collected. Methods such as visual and magnetic particle inspection can miss critical discontinuities. However, a new ASTM international standard provides a more effective method for gear examination using eddy current array, a technology that has been widely used but, until now, not standardized.

39 Programmable Separation of Runout From Profile and Lead Inspection Data for Gear Teeth With Arbitrary Modifications (March/April 1998)

A programmable algorithm is developed to separate out the effect of eccentricity (radial runout) from elemental gear inspection date, namely, profile and lead data. This algorithm can be coded in gear inspection software to detect the existence, the magnitude and the orientation of the eccentricity without making a separate runout check. A real example shows this algorithm produces good results.

40 Fahrenheit 451: Gear Up For Induction Hardening (March/April 1998)

So, you've been assigned the task to buy an induction heating system for heat treating: It's an intimidating, but by no means impossible, assignment. With the help of the information in this article, you could be able to develop common ground with your supplier and have the tools to work with him or her to get the right machine for your jobs.

41 Politics of Manufacturing (July/August 1998)

In the approximately 15 years that I have been writing editorials for Gear Technology, I've purposely avoided certain topics. Sex, religion and my own used gear machinery business are among the subjects that have always been off limits. But with this issue, I'm going to break one of my long-standing taboos by talking politics.

42 The Basics of Gear Metrology and Terminology Part I (September/October 1998)

It is very common for those working in the gear manufacturing industry to have only a limited understanding of the fundamental principals of involute helicoid gear metrology, the tendency being to leave the topic to specialists in the gear lab. It is well known that quiet, reliable gears can only be made using the information gleaned from proper gear metrology.

43 The Basics of Gear Metrology and Terminology Part II (November/December 1998)

In the last section, we discussed gear inspection; the types of errors found by single and double flank composite and analytical tests; involute geometry; the involute cam and the causes and symptoms of profile errors. In this section, we go into tooth alignment and line of contact issues including lead, helix angles, pitch, pitchline runout, testing and errors in pitch and alignment.

44 Definition and Inspection of Profile and Lead of a Worm Wheel (November/December 1999)

Traditionally, profile and lead inspections have been indispensable portions of a standard inspection of an involute gear. This also holds true for the worm of a worm gear drive (Ref. 1). But the inspection of the profile and the lead is rarely performed on a worm wheel. One of the main reasons is our inability to make good definitions of these two elements (profile and lead) for the worm wheel. Several researchers have proposed methods for profile and lead inspections of a worm wheel using CNC machines or regular involute and lead inspections of a worm wheel using CNC machines or regular involute measuring machines. Hu and Pennell measured a worm wheel's profile in an "involute" section and the lead on the "pitch" cylinder (Ref. 2). This method is applicable to a convolute helicoid worm drive with a crossing angle of 90 degrees because the wheel profile in one of the offset axial planes is rectilinear. This straight profile generates an involute on the generated worm wheel. Unfortunately, because of the hob oversize, the crossing angle between the hob and the worm wheel always deviates from 90 degrees by the swivel angle. Thus, this method can be implemented only approximately by ignoring the swivel angle. Another shortcoming of this method is that there is only one profile and one lead on each flank. If the scanned points deviated from this curve, it produced unreal profile deviation. Octrue discussed profile inspection using a profile checking machine (Ref. 3).

45 The Design and Testing of a Low Noise Marine Gear (May/June 2000)

This article offers an overview of the practical design of a naval gear for combined diesel or gas turbine propulsion (CODOG type). The vibration performance of the gear is tested in a back-to-back test. The gear presented is a low noise design for the Royal Dutch Navy's LCF Frigate. The design aspects for low noise operation were incorporated into the overall gear system design. Therefore, special attention was paid to all the parameters that could influence the noise and vibration performance of the gearbox. These design aspects, such as tooth corrections, tooth loading, gear layout, balance, lubrication and resilient mounting, will be discussed.

46 Gear Measurement Traceability and Uncertainty (July/August 2000)

Until recently, there was a void in the quality control of gear manufacturing in this country (Ref. 1). Gear measurements were not traceable to the international standard of length through the National Institute of Standards and Technology (NIST). The U.S. military requirement for traceability was clearly specified in the military standard MIL-STD-45662A (Ref. 2). This standard has now been replaced by commercial sector standards including ISO 9001:1994 (Ref. 3), ISO/IEC Guide 25 (Ref, 4), and the U.S. equivalent of ISO/IEC Guide 25 - ANSI/NCSL Z540-2-1997 (Ref. 5). The draft replacement to ISO/IEC Guide 25 - ISO 17025 states that measurements must either be traceable to SI units or reference to a natural constant. The implications of traceability to the U.S. gear industry are significant. In order to meet the standards, gear manufacturers must either have calibrated artifacts or establish their own traceability to SI units.

47 Analytical Gear Inspection: The Shape of Things to Come (July/August 2000)

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.

48 Ferrography: A Noninvasive Method to Inspect Your Gears (July/August 2000)

Would you like to be able to see the condition of the gears in your transmissions without having to open the box and physically examine them? There is a way, and not too many people know about it. It's called Wear Particle Analysis, or ferrography, and it is just starting to get noticed.

49 Girth Gear Inspection - Pre- and Post-Manufacture (August 2013)

What are the ins-and-outs of quality inspection of girth gears, from both a manufacturer and buyer perspective? Our experts respond.

50 Gear Standards and ISO GPS (October 2013)

In today’s globalized manufacturing, all industrial products having dimensional constraints must undergo conformity specifications assessments on a regular basis. Consequently, (standardization) associated with GD&T (geometrical dimensioning and tolerancing) should be un-ambiguous and based on common, accepted rules. Of course gears - and their mechanical assemblies - are special items, widely present in industrial applications where energy conversion and power transmission are involved.

51 How to Inspect a Gearbox (September 2013)

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.

52 Microgear Measurement Standards: Comparing Tactile, Optical and Computed Tomography Measurements (August 2019)

PTB's two microgear measurement standards and their analyses using seven measurement methods which are then presented, evaluated and compared with each other.

53 Lively New Book on what Distinguishes Manufacturing Precision from Perfection (August 2018)

Most of us would agree that the idea of a perfect world is absurd. Just for starters, who gets to decide what perfect means? "The Perfectionists" by Simon Winchester explores this theme as it relates to engineering.

54 Industry News (January/February 2019)

The complete Industry News section from the January/February 2019 issue of Gear Technology.

55 Trends in Induction Hardening (March/April 2019)

An Interview with Dr. Valery Rudnev, FASM, IFHTSE Fellow, Director of Science & Technology at Inductoheat, Inc.

56 Method for High Accuracy Cutting Blade Inspection (June 2019)

Inspection of the cutting blades is an important step in the bevel gear manufacture. The proper blade geometry ensures that the desired gear tooth form can be achieved. The accuracy of the process can be compromised when the blade profile consists of several small sections such as protuberance, main profile, top relief and edge radius. Another common obstacle - are outliers which can be caused by dust particles, surface roughness and also floor vibrations during the data acquisition. This paper proposes the methods to improve the robustness of the inspection process in such cases.

57 The Electric Evolution (June 2019)

CTI Symposium Presents Latest Automotive Transmission Developments and Applications.

58 Measurement Management (July 2019)

The secret to meeting today's inspection demands is influenced by the technology and those in charge of operating it.

59 Gear Noise Analysis: Design and Manufacturing Challenges Drive New Solutions for Noise Reduction (July 2019)

Gear noise is among the issues of greatest concern in today's modern gearboxes. Significant research has resulted in the application of enhancements in all phases of gear manufacturing, and the work is ongoing. With the introduction of Electric Vehicles (EV), research and development in this area has surged in recent years. Most importantly, powerful new noise analysis solutions are fast becoming available.

60 Tooth Thickness Tolerance and AGMA 2002-C16 (July 2019)

A reader asks: We are currently revising our gear standards and tolerances and a few questions with the new standard AGMA 2002-C16 have risen. Firstly, the way to calculate the tooth thickness tolerance seems to need a "manufacturing profile shift coefficient" that isn't specified in the standard; neither is another standard referred to for this coefficient. This tolerance on tooth thickness is needed later to calculate the span width as well as the pin diameter. Furthermore, there seems to be no tolerancing on the major and minor diameters of a gear.

61 Fully Automated Roughness Measurement on Gears — Even on the Shop Floor (July 2019)

Klingelnberg presents the technical aspects of its roughness measurement system.

62 Evaluation of Carburized & Ground Face Gears (September/October 2000)

Designers are constantly searching for ways to reduce rotocraft drive system weight. Reduced weight can increase the payload, performance, or power density of current and future systems. One example of helicopter transmission weight reduction was initiated as part of the United States Army Advanced Rotocraft Transmission program. This example used a split-torque, face-gear configuration concept (Ref. 1). compared to a conventional design with spiral-bevel gears, the split-torque, face-gear design showed substantial weight savings benefits. Also, the use of face gears allows a wide-range of possible configurations with technical and economic benefits (Ref. 2).

63 Inspection System Upgrades Meet EV Gear Challenges (July 2018)

Delta Research upgrades its Gleason Metrology Workhorses to meet the development requirements of the latest electrical drive vehicles.

64 Product News (March/April 2013)

The complete Product News section from the March/April 2013 issue of Gear Technology.

65 Product News (July 2014)

The complete Product News section from the July 2014 issue of Gear Technology.

66 Gleason Hosts WZL Gear Conference USA (November/December 2014)

The 5th WZL Gear Conference USA took place October 22-23 at the Gleason Works facility in Rochester, NY. More than 130 gear technologists participated

67 Product News (August 2015)

News about the newest products from the Gear Industry

68 Defying the Oil Ripple (March/April 2016)

The oil industry is (pardon the pun) tanking. That may conjure up horrific images of other industries following suit in a domino effect of collective collapse into the overabundant oil slick the industry is currently drowning in, but not everyone is getting knocked down alongside the oil sector.

69 Plastic Gearing Continues Converting the Unconverted (March/April 2016)

Plastic gears are everywhere today - throughout your car, at the oceans' lowest depths, in deep space. The question, when is a metal gear a candidate for plastic conversion, can be addressed in three words, i.e. what's the application?

70 All-For-One, One-For-All (May 2016)

The "less is more" mantra is certainly a rallying cry in manufacturing. Technologies like multiaxis machining, 3D printing and automation are enabling companies to be more efficient, cost-conscious and flexible on the shop floor.

71 Heat Treating 4.0 (March/April 2017)

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.

72 Gear Expo 2017 and ASM Heat Treat 2017 Booth Previews (September/October 2017)

The latest technology on display in Columbus, OH. October 24-26.

73 Product News (May 2018)

Safe cutting tool clamping, superfinishing gear shafts, gearbox parts cleaning, gear deburring and more new gear-related products.

74 Complete Measurement of Gearbox Components (July 2018)

In today's production environment, a variety of different measurement devices is used to assess the quality and accuracy of workpieces. These devices include CMMs, gear checkers, form testers, roughness testers, and more. It requires a high machine investment and a high handling effort - especially if a full end-of-line measurement is needed. One approach to reduce quality costs is to include all measurements in one single machine that is suitable and robust enough for use in production.

75 In-Process, Complete Gear Inspection at Light Speeds (July 2018)

New GRSL technology adds value to high-volume transmission gear inspection by combining non-contact laser inspection with tried-and-true composite roll testing.

76 Rebuilding a Metrology Infrastructure (January/February 1996)

The American Society of Mechanical Engineers (ASME) announced at Gear Expo '95 that a national service for the calibration of involute artifacts is now available at the Department of Energy's Y-12 Plant in Oak Ridge, TN.

77 Gear Inspection in a Shop Floor Environment (July 2015)

As in nearly all industries, more costeffective solutions are currently called for in the gear manufacturing industry.

78 GT Extras (January/February 2014)

Video from C&B Machinery; Introducing the Gear Technology Blog, featuring technical editor Charles D. Schultz; plus an online-exclusive article on big gear inspection.

79 Super-Sized Quality Control (January/February 2014)

It's not easy being big. Maybe that's not exactly how the phrase goes, but it's applicable, particularly when discussing the quality requirements of large gears. The size alone promises unique engineering challenges. BONUS Online Exclusive: Big or Small - Inspection is Key to Success.

80 Practical Considerations for the Use of Double-Flank Testing for the Manufacturing Control of Gearing - Part I (January/February 2014)

Part I of this paper describes the theory behind double-flank composite inspection, detailing the apparatus used, the various measurements that can be achieved using it, the calculations involved and their interpretation. Part II, which will appear in the next issue, includes a discussion of the practical application of double-flank composite inspection, especially for large-volume operations. Part II covers 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.

81 Hardening Technology Focuses on Dimensional Accuracy (March/April 2014)

New technology from Eldec/EMAG helps control the induction hardening process.

82 Practical Considerations for the Use of Double-Flank Testing for the Manufacturing Control of Gearing - Part II (March/April 2014)

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.

83 No Compromising on Quality at Allison Transmission (July 2014)

Gleason 350GMS helps put higher quality, more reliable gears into its next-generation TC10 automatic transmission.

84 Portable Gear Inspection (July 2014)

Compact, custom and portable solutions are gaining more attention in manufacturing today as companies seek out the tools that offer the greatest productivity gains on the shop floor. Gear inspection seems to be following suit.

85 Innovative Induction Hardening Process with Pre-heating for Improved Fatigue Performance of Gear Component (July 2014)

Contact fatigue and bending fatigue are two main failure modes of steel gears, while surface pitting and spalling are two common contact fatigue failures -- caused by alternating subsurface shear stresses from the contact load between two gear mates. And when a gear is in service under cyclic load, concentrated bending stresses exist at the root fillet -- the main driver of bending fatigue failures. Induction hardening is becoming an increasingly popular response to these problems, due to its process consistency, reduced energy consumption, clean environment and improved product quality -- but not without issues of its own (irregular residual stresses and bending fatigue). Thus a new approach is proposed here that flexibly controls the magnitude of residual stress in the regions of root fillet and tooth flank by pre-heating prior to induction hardening. Using an external spur gear made of AISI 4340 as an example, this new concept/process is demonstrated using finite element modeling and DANTE commercial software.

86 Measuring Residual Stress in Gears (March/April 2015)

I have heard that X-ray diffraction does not tell the whole story and that I should really run a fatigue test. I understand this may be the best way, but is there another method that gives a high degree of confidence in the residual stress measurement?

87 I Like Big Gears and I Cannot Lie! (July 2015)

Many years ago, when asked how the five-meter gear was checked, the quality manager responded, “When they’re that big, they’re never bad!” That may have been the attitude and practice in the past, but it no longer serves the manufacturer nor the customer. Requirements have been evolving steadily, requiring gears to perform better and last longer.

88 Overlapping Pursuits (July 2018)

More than any other field, IIoT overlaps directly with metrology's mission to analyze and measure as much of the manufacturing process as possible, and it's no surprise that the latter is utilizing the former.

89 Practical Gear Characteristics: Process Characteristics of the Most Popular Cutting Methods (March/April 2016)

The cutting process consists of either a roll only (only generating motion), a plunge only or a combination of plunging and rolling. The material removal and flank forming due to a pure generating motion is demonstrated in the simplified sketch in Figure 1 in four steps. In the start roll position (step 1), the cutter profile has not yet contacted the work. A rotation of the work around its axis (indicated by the rotation arrow) is coupled with a rotation of the cutter around the axis of the generating gear (indicated by the vertical arrow) and initiates a generating motion between the not-yet-existing tooth slot of the work and the cutter head (which symbolizes one tooth of the generating gear).

90 The Wait is Over for Lab-Level Shop Floor Inspection (July 2016)

Schafer Gear Works greatly reduces gear inspection queue time and adds precious capacity by installing Gleason's new "shop-hardened" 300GMS P gear inspection system.

91 A Proposed Pre-Finish Cylindrical Gear Quality Standard (September/October 2016)

This proposed standard would not make any recommendations regarding the required quality for any application. The intent is to establish standard pre-finish quality classes for typical finishing operations, which only include the inspection elements that are important to properly evaluate pre-finish gear quality as it applies to the finishing operation. It would be the responsibility of the manufacturing/process engineer, quality engineer, or other responsible individual to establish the required pre-finish quality class for their application.

92 Measuring Left and Right (July 2017)

CMM Inspection vs. GMM Inspection. Speed is the name of the game.

93 Gear Inspection at Light Speed (July 2017)

Revolutionary new inspection technologies are helping gear manufacturers develop and produce more complex, higher quality gears in a fraction of the time it used to take.

94 You Cannot Rely on Labor Efficiency Reporting (July 2017)

In manufacturing, we all know that tracking statistics on your operation is essential for understanding how you're doing, as well as identifying areas for improvement. But what does the efficiency metric actually tell you?

95 Friction Coefficient of Differently Treated Steel Surfaces (November/December 2017)

A reader asks about ion-nitride finished shafts and the proper friction coefficient to be used for calculations.

96 Frenco REANY Gear Inspection Software Melds Data from Multiple Sources (March/April 2018)

REANY is software for the evaluation of gears and splines that have been measured completely on all teeth. It is suited to both quality assessment and analyzing the causes for deviations. REANY is short for Reality Analysis.

97 Pushing Boundaries (March/April 2018)

Induction hardening is becoming an increasingly popular alternative to thermochemical diffusion processes such as carburizing, and as it does so, manufacturers are on a never-ending quest to expand the scope of what's possible with the technology.

98 Industry News (March/April 2018)

Germany adopts ISO 1328 standard for the measurement of gears, plus other news and announcements from around the industry.

99 Noise Reduction in Plastic & Powder Metal Gear Sets (July/August 1996)

The data discussed in this article was taken from an upright vacuum cleaner. This was a prototype cleaner that was self-propelled by a geared transmission. It was the first time that the manufacturer had used a geared transmission in this application.

100 The Next Step in Bevel Gear Metrology (January/February 1996)

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.

101 Better Gears & Splines With Metrology (July 2007)

What does it mean to make "better" gears? Better gears more closely resemble the intended design parameters.

102 Protecting Our Own (January/February 2011)

Publisher Michael Goldstein discusses the loss of U.S. manufacturing capability and what we should do about it.

103 Innovative Analysis and Documentation of Gear Test Results (September/October 2008)

In this paper, a method is presented for analyzing and documenting the pitting failure of spur and helical gears through digital photography and automatic computerized evaluation of the damaged tooth fl ank surface. The authors have developed an accurate, cost-effective testing procedure that provides an alternative to vibration analysis or oil debris methods commonly used in conjunction with similar test-rig programs.

104 Producing Profile and Lead Modifications in Threaded Wheel and Profile Grinding (January/February 2010)

Modern gearboxes are characterized by high torque load demands, low running noise and compact design. In order to fulfill these demands, profile and lead modifications are being applied more often than in the past. This paper will focus on how to produce profile and lead modifications by using the two most common grinding processes—threaded wheel and profile grinding. In addition, more difficult modifications—such as defined flank twist or topological flank corrections—will also be described in this paper.

105 Implementing ISO 18653-Gears: Evaluation of Instruments for Measurement of Individual Gears (May 2010)

A trial test of the calibration procedures outlined in ISO 18653—Gears: 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.

106 Improved Inspection Software Helps Provide Optimum Cutting Results (July 2010)

Klingelnberg measuring centers eliminate trial-and-error with modern analysis tools.

107 Large Gears, Better Inspection (July 2010)

Investment in Gleason GMM Series inspection equipment helps drive Milwaukee Gear's expansion into profitable new markets around the world—all hungry for high-precision custom gears and gear drives.

108 User-Friendly Gear Measurement (July 2010)

Good timing leads to partnership between Process Equipment and Schafer Gear.

109 Effects of Profile Corrections on Peak-to-Peak Transmission Error (July 2010)

Profile corrections on gears are a commonly used method to reduce transmission error, contact shock, and scoring risk. There are different types of profile corrections. It is a known fact that the type of profile correction used will have a strong influence on the resulting transmission error. The degree of this influence may be determined by calculating tooth loading during mesh. The current method for this calculation is very complicated and time consuming; however, a new approach has been developed that could reduce the calculation time.

110 Cotta Transmission Installs CMM with Gear Checking Module (July 2010)

Xspect Solutions Provides Wenzel Bridge-Type CMM Equipped with OpenDMIS Software for Basic Gear Measuring Capability with CMM Flexibility.

111 Optimizing Gear Geometry for Minimum Transmission Error, Mesh Friction Losses and Scuffing Risk Through Computer- Aided Engineering (August 2010)

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.

112 The Merits of Multifunctional Machining (January/February 2011)

Higher productivity, faster setup times and single unattended operations are just a few of the capabilities gear manufacturers seek in the multifunctional machine tool market.

113 Injection Molded Innovation (June 2008)

Alternative business strategies from some alternative gear manufacturers.

114 Measurement of Directly Designed Gears with Symmetric and Asymmetric Teeth (January/February 2011)

In comparison with the traditional gear design approach based on preselected, typically standard generating rack parameters, the Direct Gear Design method provides certain advantages for custom high-performance gear drives that include: increased load capacity, efficiency and lifetime; reduced size, weight, noise, vibrations, cost, etc. However, manufacturing such directly designed gears requires not only custom tooling, but also customization of the gear measurement methodology. This paper presents definitions of main inspection dimensions and parameters for directly designed spur and helical, external and internal gears with symmetric and asymmetric teeth.

115 Zoller and Ingersoll Partner for Measuring Hob Cutters (March/April 2011)

With growing markets in aerospace and energy technologies, measuring hob cutters used in gear cutting is becoming an essential requirement for workpieces and machine tools. Zoller, a provider of solutions for tool pre-setters, measuring and inspection machines and tool management software, has developed a new partnership with Ingersoll/Germany for shop floor checking of hob cutters by a combined hardware and software approach.

116 Induction Heat Treating Gains Ground through Advances in Technology (March/April 2011)

In recent years, there has been significant interest in expanding the use of induction hardening in gear manufacturing operations. Over the past several years, many of the limits to induction hardening have shrunk, thanks to recent advances in technology, materials and processing techniques.

117 Gear Measuring Machine by NDG Method for Gears Ranging from Miniature to Super-Large (March/April 2011)

A new inspection method has several advantages over traditional methods, especially for very large or very small gears.

118 Dearborn Precision Puts Dual Purpose Zeiss CMM to the Task (May 2011)

When parts you manufacture pass through numerous processes such as deep hole drilling, machining, hobbing and grinding, a CMM is essential when your customers require 100 percent in-process and final inspection.

119 An Emphasis on Accuracy (June/July 2011)

Meeting the many challenges of large gear inspection.

120 Super-Reduction Hypoid Gears (August 2011)

Super-reduction hypoid gears (SRH) are bevel worm gears with certain differences regarding hypoid gears. If two axes are positioned in space and the task is to transmit motion and torque between them using some kind of gears with a ratio above 5 and even higher than 50, the following cases are commonly known. Tribology Aspects in Angular Transmission Systems, Part VIII.

121 Benefit of Psychoachoustic Analyzing Methods for Gear Noise Investigation (August 2011)

This article provides an overview of the benefits of using psychoacoustic characteristics for describing gear noise. And with that, human hearing and the most important psychoacoustic values are introduced. Finally, results of noise tests with different gear sets aree presented. The tests are the basis for a correlation analysis between psychoacoustic values and gear characteristics.

122 Not All Good Ideas Are Brand New (September 2011)

A reader clarifies technology presented in the March/April 2011 issue.

123 Liebherr's LDF350 Offers Complete Machining in New Dimension (November/December 2011)

The objective, according to Dr.- Ing. Hansjörg 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.

124 Induction Hardening of Gears and Critical Components - Part I (September/October 2008)

Induction hardening is a heat treating technique that can be used to selectively harden portions of a gear, such as the flanks, roots and tips of teeth, providing improved hardness, wear resistance, and contact fatigue strength without affecting the metallurgy of the core and other parts of the component that don’t require change. This article provides an overview of the process and special considerations for heat treating gears. Part I covers gear materials, desired microsctructure, coil design and tooth-by-tooth induction hardening.

125 Update on the National Center for Gear Metrology (May 2008)

The status on traceability of gear artifacts in the United States.

126 Multifunctional Advancements (January/February 2012)

The latest in big gear machining with DMG/Mori Seiki.

127 Gear Inspection and Chart Interpretation (May/June 1985)

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.

128 Effects of Axle Deflection and Tooth Flank Modification on Hypoid Gear Stress Distribution and Contact Fatigue Life (August 2009)

As is well known in involute gearing, “perfect” involute gears never work perfectly in the real world. Flank modifications are often made to overcome the influences of errors coming from manufacturing and assembly processes as well as deflections of the system. The same discipline applies to hypoid gears.

129 Single Flank Data Analysis and Interpretation (September/October 1985)

Much of the information in this article has been extracted from an AGMA Technical Paper, "What Single Flank Testing Can Do For You", presented in 1984 by the author

130 Industry Forum (September/October 1985)

Your May/June issue contains a letter from Edward Ubert of Rockwell International with some serious questions about specifying and measuring tooth thickness.

131 Material Selection and Heat Treatment (July/August 1985)

Before the optimum mechanical properties can be selected, the working stress must be determined, based on recommended allowable stresses.

132 Grinding Induced Changes in Residual Stresses of Carburized Gears (March/April 2009)

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.

133 Induction Hardening of Gears and Critical Components - Part II (November/December 2008)

Part I, which was published in the September/October 2008 issue, covered gear materials, desired microstructure, coil design and tooth-by-tooth induction hardening. Part II covers spin hardening and various heating concepts used with it.

134 Single-Flank Testing of Gears (May/June 2004)

This article was originally published 20 years ago, in Gear Technology’s first issue. It describes a method of evaluating the smoothness, or lack of smoothness, of gear motion. This lack of smoothness of motion, known as “transmission error,” is responsible for excitation of gear noise and problems of gear accuracy and sometimes has a relationship to gear failure.

135 Revolutions (May/June 2004)

"Frenco--Inspecting All Flanks in Minutes."

136 Gear Failure Analysis Involving Grinding Burn (January/February 2009)

When gears are case-hardened, it is known that some growth and redistribution of stresses that result in geometric distortion will occur. Aerospace gears require post case-hardening grinding of the gear teeth to achieve necessary accuracy. Tempering of the case-hardened surface, commonly known as grinding burn, occurs in the manufacturing process when control of the heat generation at the surface is lost.

137 How Are You Dealing with the Bias Error in Your Helical Gears (May 2009)

This paper initially defines bias error—the “twisted tooth phenomenon.” Using illustrations, we explain that bias error is a by-product of applying conventional, radial crowning methods to produced crowned leads on helical gears. The methods considered are gears that are finished, shaped, shaved, form and generated ground. The paper explains why bias error occurs in these methods and offers techniques used to limit/eliminate bias error. Sometimes, there may be a possibility to apply two methods to eliminate bias error. In those cases, the pros/cons of these methods will be reviewed.

138 Calibration of Two-Flank Roll Testers (May 2008)

The presence of significant errors in the two-flank roll test (a work gear rolled in tight mesh against a master gear) is well-known, but generally overlooked.

139 Practical Magic - Metrology Products Keep Pace with Machine Technology (July 2009)

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.

140 New ANSI-AGMA Accuracy Standards for Gears (March/April 2004)

AGMA has started to replace its 2000-A88 standard for gear accuracy with a new series of documents based largely on ISO standards. The first of the replacement AGMA standards have been published with the remainder coming in about a year. After serving as a default accuracy specification for U.S. commerce in gear products for several decades, the material in AGMA 2000-A88 is now considered outdated and in need of comprehensive revision.

141 In-Situ Measurement of Stresses in Carburized Gears via Neutron Diffraction (May 2009)

This paper presents the results of research directed at measuring the total stress in a pair of statically loaded and carburized spur gears. Measurements were made to examine the change in total stress as a function of externally applied load and depth below the surface.

142 Steadfast and Streamlined: Can Lean Soften the Economic Blow (August 2009)

Two high-volume gear production cells grace the shop floor at Delta Research Corporation in Livonia, Michigan. Thanks to lean manufacturing, these cells have never shipped a defective part to a customer since they were developed over three years ago.

143 Extending the Benefits of Elemental Gear Inspection (July 2009)

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 “composite” 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.

144 Characteristics of Master Gears (November/December 2006)

The two-flank roll test measures kickout (tooth-to-tooth composite error) and tooth thickness. In this article, it will be shown that measured values vary with the number of teeth on the master gear.

145 Tooth Flank Corrections of Wide Face Width Helical Gears that Account for Shaft Deflections (January/February 2005)

This paper discusses the influence of tip relief, root relief, load modification, end relief and their combinations on gear stresses and transmission errors due to shaft deflections.

146 The Heat Goes On - Gear Up for Induction Hardening (March/April 2005)

This article covers preventive maintenance and modification to machinery to induction harden different types of gear.

147 A Novel Concept for High Accuracy Gear Calibration (May/June 2005)

The German National Metrology Institute has developed a novel calibration concept that allows for highly accurate calibration of product-like artifacts.

148 Determining Power Losses in the Helical Gear Mesh (September/October 2005)

This article reviews mathematical models for individual components associated with power losses, such as windage, churning, sliding and rolling friction losses.

149 Flank Breakage on Gears for Energy Systems (November/December 2011)

Gear flank breakage can be observed on edge zone-hardened gears. It occurs, for example, on bevel gears for water turbines, on spur gears for wind energy converters and on single- and double-helical gears for other industrial applications.

150 Controlling Gear Distortion and Residual Stresses During Induction Hardening (March/April 2012)

Induction hardening is widely used in both the automotive and aerospace gear industries to minimize heat treat distortion and obtain favorable compressive residual stresses for improved fatigue performance. The heating process during induction hardening has a significant effect on the quality of the heat-treated parts. However, the quenching process often receives less attention even though it is equally important.

151 Measurement Error Induced by Measuring over Pins Instead of Balls (January/February 1996)

The purpose of this article is to clarify some terms and methods used in measuring the size of gears. There is also an explanation given of the error induced and how to correct for it in certain cases when the measurement is made using pins instead of balls.

152 Little Things Mean A Lot (March/April 1993)

"God is in the details," says the philosopher. What he meant was that on the scale of the universe, it's not just the galaxies, the planets, the mountain ranges, or the major rivers that are important. So are the subatomic particles and the genes. It's the little things that make all the difference.

153 Viewpoint (November/December 1991)

Dear Editor: In Mr. Yefim Kotlyar's article "Reverse Engineering" in the July/August issue, I found an error in the formula used to calculate the ACL = Actual lead from the ASL = Assumed lead.

154 Gear Inspection Chart Evaluation; Specifying Unusual Worm Gear Sets (November/December 1991)

Question: When evaluating charts from a gear inspection machine, it is sometimes found that the full length of the profile traces vary, and that sometimes they are less than the length of active profile (above start of active profile-SAP) by up to 20%. This condition could be caused by a concentricity error between tooth grinding and shaping, or by unequal stock removal when grinding. (See Fig. 1.) Is it possible that some of the variation is coming from the inspection machine? How can variation from the inspection machine be reduced?

155 Gear Hardness Technology (March/April 1992)

In a very general sense, increasing the hardness of a steel gear increases the strength of the gear. However, for each process there is a limit to its effectiveness. This article contains background information on each of the processes covered. In each section what is desired and what is achievable is discussed. Typical processes are presented along with comments on variables which affect the result. By reviewing the capabilities and processes, it is possible to determine the limits to each process.

156 Investment Tax Credits - A Good Idea Whose Time Has Come (March/April 1992)

Of timing is crucial in the successful implementation of good ideas, then now is the time to reinstate a good idea that fell into disfavor in the mid-1980s. Now is the time to include the investment tax credit as part of whatever inevitable tax structure tinkering is going to take place during this election year.

157 Effects of Temperature on Gage Repeatability & Reproducibility (May/June 1992)

Temperature Induced Dimensional Changes Temperature causes various materials to change size at different rate, known as their Coefficients of Expansion (COE). The effects of this phenomenon on precision dimensional measurements are continuous and costly to industry. Precautions can be taken to allow parts and gages to temperature stabilize before conducting gage R & R studies, but the fact remains that on the shop floor temperatures vary all the time. The slow pace at which industry has accepted this reality probably has to do with the subtlety of these tiny size variations and our inability to sense gradual, but significant temperature changes.

158 Gear Inspection and Measurement (July/August 1992)

The purpose of gear inspection is to: Assure required accuracy and quality, Lower overall cost of manufacture by controlling rejects and scrap, Control machines and machining practices and maintain produced accuracy as machines and tools wear, Determine hear treat distortions to make necessary corrections.

159 Reader Dialogue: Functional Measurement of Gears; More Good Gear Books (September/October 1992)

From time to time, the editors of "Shop Floor" receive correspondence from readers relating to particular articles they have written for past issues. As one of the purposes of this column is to provide a forum for the exchange of ideas, we reproduce here two of these letters and their replies. The subject of the first is the functional measurement of gears. (See Gear Technology, Sept/Oct, 1991, p. 17) Robert E. Smith writes the reply.

160 Line of Action: Concepts & Calculations (January/February 1993)

In the past gear manufacturers have had to rely on hob manufacturers' inspection of individual elements of a hob, such as lead, involute, spacing, and runout. These did not always guarantee correct gears, as contained elements may cause a hob to produce gears beyond tolerance limits.

161 Improving Gear Manufacturing Quality With Surface Texture Measurement (March/April 1993)

The working surfaces of gear teeth are often the result of several machining operations. The surface texture imparted by the manufacturing process affects many of the gear's functional characteristics. To ensure proper operation of the final assembly, a gear's surface texture characteristics, such as waviness and roughness, can be evaluated with modern metrology instruments.

162 Dual Frequency Induction Gear Hardening (March/April 1993)

In the typical gear production facility, machining of gear teeth is followed by hear treatment to harden them. The hardening process often distorts the gear teeth, resulting in reduced and generally variable quality. Heat treating gears can involve many different types of operations, which all have the common purpose of producing a microstructure with certain optimum properties. Dual frequency induction hardening grew from the need to reduce cost while improving the accuracy (minimizing the distortion) of two selective hardening processes: single tooth induction and selective carburizing.

163 Single Flank Measuring; Estimating Horsepower Capacity (September/October 1991)

Question: What is functional measurement and what is the best method for getting truthful answers?

164 Computerized Hob Inspection & Applications of Inspection Results - Part I (May/June 1994)

Can a gear profile generated by the hobbing method be an ideal involute? In strictly theoretical terms - no, but in practicality - yes. A gear profile generated by the hobbing method is an approximation of the involute curve. Let's review a classic example of an approximation.

165 Computerized Hob Inspection & Applications of Inspection Results Part II (July/August 1994)

Flute Index Flute index or spacing is defined as the variation from the desired angle between adjacent or nonadjacent tooth faces measured in a plane of rotation. AGMA defines and provides tolerance for adjacent and nonadjacent flute spacing errors. In addition, DIN and ISO standards provide tolerances for individual flute variation (Fig. 1).

166 Effect of Extended Tooth Contact on the Modeling of Spur Gear Transmissions (July/August 1994)

In some gear dynamic models, the effect of tooth flexibility is ignored when the model determines which pairs of teeth are in contact. Deflection of loaded teeth is not introduced until the equations of motion are solved. This means the zone of tooth contact and average tooth meshing stiffness are underestimated, and the individual tooth load is overstated, especially for heavily loaded gears. This article compares the static transmission error and dynamic load of heavily loaded, low-contact-ratio spur gears when the effect of tooth flexibility has been considered and when it has been ignored. Neglecting the effect yields an underestimate of resonance speeds and an overestimate of the dynamic load.

167 A Comparison of ISO 4156-ANSI B92.2M - 1980 With Older Imperial Standards (September/October 1994)

The purpose of this article is to discuss ISO 4156/ANSI B92.2M-1980 and to compare it with other, older standards still in use. In our experience designing and manufacturing spline gauges and other spline measuring or holding devices for splined component manufacturers throughout the world, we are constantly surprised that so many standards have been produced covering what is quite a small subject. Many of the standards are international standards; others are company standards, which are usually based on international standards. Almost all have similarities; that is, they all deal with splines that have involute flanks of 30 degrees, 37.5 degrees or 45 degrees pressure angle and are for the most part flank-fitting or occasionally major-diameter-fitting.

168 Quality Gear Inspection - Part I (September/October 1994)

Quality gear inspection means doing the "right" inspections "right." A lot of time and money can be spent doing the wrong types of inspections related to function and doing them incorrectly. As we will discover later, such things as runout can creep into the manufacturing and inspection process and completely ruin any piece of data that is taken. this is one of the most important problems to control for quality inspection.

169 Quality Gear Inspection - Part II (November/December 1994)

This section will deal with the use of gear inspection for diagnostic purposes rather than quality determination. The proper evaluation of various characteristics in the data can be useful for the solution of quality problems. It is important to sort out whether the problem is coming from the machine, tooling and/or cutters, blanks, etc. An article by Robert Moderow in the May/June 1985 issue of Gear Technology is very useful for this purpose.

170 ADI - A Designer Gear Material (March/April 1995)

If someone were to tell you that he had a gear material that was stronger per pound than aluminum, as wear-resistant as steel, easier to machine than free-machining steel and capable of producing gears domestically for 20% less than those now cut from foreign made forgings, would you consider that material to be "high tech"? Probably. Well, throw out all the pre-conceived notions that you may have had about "high tech" materials. The high-performance material they didn't teach you about in school is austempered ductile iron (ADI).

171 Developing a Total Productive Maintenance System (May/June 1995)

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.

172 How to Avoid Errors When Measuring Step Gears (July/August 1995)

There are problems in dimensional measurement that should be simple to solve with standard measuring procedures, but aren't. In such cases, using accepted practices may result in errors of hundreds of microns without any warning that something is wrong.

173 Gear Inspection For The Long Haul (September/October 1995)

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?

174 Recent Developments in Gear Metrology (November/December 1991)

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.

175 Gear Fundamentals Reverse Engineering (July/August 1991)

Whether gear engineers have to replace an old gear which is worn out, find out what a gear's geometry is after heat treatment distortion, or just find out parameters of gears made by a competitor, sometimes they are challenged with a need to determine the geometry of unknown gears. Depending on the degree of accuracy required, a variety of techniques are available for determining the accuracy of an unknown gear. If a high degree of precision is important, a gear inspection device has to be used to verify the results. Frequently, several trial-and-error attempts are made before the results reach the degree of precision required.

176 Single Flank Testing of Gears (May/June 1984)

Presumably, everyone who would be interested in this subject is already somewhat familiar with testing of gears by traditional means. Three types of gear inspection are in common use: 1) measurement of gear elements and relationships, 2) tooth contact pattern checks and 3) rolling composite checks. Single Flank testing falls into this last category, as does the more familiar Double Flank test.

177 Contact Surface Topology of Worm Gear Teeth (March/April 1988)

Among the various types of gearing systems available to the gear application engineer is the versatile and unique worm and worm gear set. In the simpler form of a cylindrical worm meshing at 90 degree axis angle with an enveloping worm gear, it is widely used and has become a traditional form of gearing. (See Fig. 1) This is evidenced by the large number of gear shops specializing in or supplying such gear sets in unassembled form or as complete gear boxes. Special designs as well as standardized ratio sets covering wide ratio ranges and center distanced are available with many as stock catalog products.

178 Austempered Ductile Iron: Technology Base Required for an Emerging Technology (October/November 1984)

This paper addresses Austempered Ductile Iron (ADI) as an emerging Itechnology and defines its challenge by describing the state-of-the-art of incumbent materials. The writing is more philosophical in nature than technical and is presented to establish a perspective.

179 Viewpoint (March/April 1986)

I received a letter from Mr. G. W. Richmond, Sullivan Machinery Company, N.H., in which in addition to correcting mistyping, he made several suggestions concerning my article "General Equations for Gear Cutting Tool Calculations."

180 Generating and Checking Involute Gear Teeth (May/June 1986)

It has previously been demonstrated that one gear of an interchangeable series will rotate with another gear of the same series with proper tooth action. It is, therefore, evident that a tooth curve driven in unison with a mating blank, will "generate" in the latter the proper tooth curve to mesh with itself.

181 A Wheel Selection Technique for Form Gear Grinding (May/June 1986)

Until recently, form gear grinding was conducted almost exclusively with dressable, conventional abrasive grinding wheels. In recent years, preformed, plated Cubic Boron Nitride (CBN) wheels have been introduced to this operation and a considerable amount of literature has been published that claim that conventional grinding wheels will be completely replaced in the future. The superior machining properties of the CBN wheel are not disputed in this paper.

182 Identification of Gear Noise with Single Flank Composite Measurement (May/June 1986)

Anyone involved in the design, manufacture and use of gears is concerned with three general characteristics relative to their application: noise, accuracy, and strength or surface durability. In the article, we will be dealing with probably the most aggravating of the group, gear noise.

183 Checking Large Gears (March/April 1987)

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.

184 Longitudinal Load Distribution Factor for Straddle- and Overhang-Mounted Spur Gears (July/August 1987)

A pair of spur gears generally has an effective lead error which is caused, not only by manufacturing and assembling errors, but also by the deformations of shafts, bearings and housings due to the transmitted load. The longitudinal load distribution on a contact line of the teeth of the gears is not uniform because of the effective lead error.

185 Effects of Hob Quality and Resharpening Errors on Generating Accuracy (September/October 1987)

The modern day requirement for precision finished hobbed gears, coupled with the high accuracy characteristics of modern CNC hobbing machines, demands high tool accuracy.

186 The Interrelationship of Tooth Thickness Measurements as Evaluated by Various Measuring Techniques (September/October 1987)

The first commandment for gears reads "Gears must have backlash!" When gear teeth are operated without adequate backlash, any of several problems may occur, some of which may lead to disaster. As the teeth try to force their way through mesh, excessive separating forces are created which may cause bearing failures. These same forces also produce a wedging action between the teeth with resulting high loads on the teeth. Such loads often lead to pitting and to other failures related to surface fatigue, and in some cases, bending failures.

187 Selection of a Proper Ball Size to Check an Involute Spur or Helical Cear Tooth (September/October 1987)

A much-used method for checking the tooth thickness of an involute gear tooth is to measure the dimension over two balls placed in most nearly opposite spaces in the case of external gears, and the dimension between the balls in the case of internal gears. This measurement is then checked against a pre-calculated dimension to denote an acceptable part.

188 Calculation of Optimum Tooth Flank Corrections for Helical Gears (September/October 1988)

The load carrying behavior of gears is strongly influenced by local stress concentrations in the tooth root and by Hertzian pressure peaks in the tooth flanks produced by geometric deviations associated with manufacturing, assembly and deformation processes. The dynamic effects within the mesh are essentially determined by the engagement shock, the parametric excitation and also by the deviant tooth geometry.

189 Our Experts Discuss... (March/April 1991)

Question: I have just become involved with the inspection of gears in a production operation and wonder why the procedure specifies that four involute checks must be made on each side of the tooth of the gear being produced, where one tooth is checked and charted in each quadrant of the gear. Why is this done? These particular gears are checked in the pre-shaved, finish-shaved, and the after-heat-treat condition, so a lot of profile checking must be done.

190 Mr. None-of-the-Above Wins Again (November/December 1988)

A few years ago, during a presidential election campaign, I saw an editorial cartoon that depicted a man standing outside a voting booth with a bemused expression on his face. Over the door to the booth was a quotation from Dante: "Abandon hope, all ye who enter here." Unfortunately for all of us, the grim jest is just as timely now. Once again, when we make our choice for president this year, the pick seems to be between Mr. Well-He's-Not-Actually-Awful and Mr. At-Least-He's-Not-The-Other-Guy. A candidate who can arouse truly positive and hopeful feelings in the electorate is once again not on the ballot.

191 Gear Span Measurement - An Analytical Approach (May/June 1989)

The purpose of this article is to describe an analytical method free of the drawbacks mentioned above and providing absolutely reliable results.

192 White Etching Areas on Case-Hardened Gears (September/October 1989)

The phenomenon of white layers, which arises from high stress, can be observed under a microscope after the white layers have been treated with a weak nitric acid solution. Their occurrences in zones of high shear stress can provide qualitatively valuable indications of the size and direction of the stress, and they can point out possible starting points for flank damage. An investigation of this phenomenon is described.

193 Capital Gains, Societal Gains, or No Gains At All (March/April 1990)

Taxes may be one of the only two sure things in life, but that doesn't make them popular. Nobody is happy to pay them, and the bigger the amount due, the unhappier the taxpayer. Conversely, politicians know that coming out in favor of a tax cut is the equivalent of voting for apple pie and motherhood. It's a sure-fire success at the ballot box.

194 Tomorrow's Gear Inspection Systems: Arriving Just in Time (June/July 2012)

Gleason's GMS analytical gear inspection systems provide all the right features at Eaton Corp.

195 Gear Quality Inspection: How Good is Yours (June/July 2012)

How well you conduct your inspections can be the difference-maker for securing high-value contracts from your customers. And as with most other segments of the gear industry, inspection continues striving to attain “exact science” status. With that thought in mind, following is a look at the state of gear inspection and what rigorous inspection practices deliver—quality.

196 Runout, Helix Accuracy and Shaper Cutters (June/July 2012)

Our experts discuss runout and helix accuracy, as well as the maximum number of teeth in a shaper cutter.

197 Towards an Improved AGMA Accuracy Classification System on Double-Flank Composite Measurements (June/July 2012)

AGMA introduced ANSI/AGMA 2015–2–A06— Accuracy Classification System: Radial System for Cylindrical Gears, in 2006 as the first major rewrite of the double-flank accuracy standard in over 18 years. This document explains concerns related to the use of ANSI/AGMA 2015–2–A06 as an accuracy classification system and recommends a revised system that can be of more service to the gearing industry.

198 The Effects of Surface Hardening on the Total Gear Manufacturing System (January/February 1991)

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.

199 What Is Runout, And Why Should I Worry About It (January/February 1991)

Runout is a troublemaker! Good shop practice for the manufacture or inspection of gears requires the control of runout. Runout is a characteristic of gear quality that results in an effective center distance variation. As long as the runout doesn't cause loss of backlash, it won't hurt the function of the gear, which is to transmit smooth motion under load from one shaft to another. However, runout does result in accumulated pitch variation, and this causes non-uniform motion, which does affect the function of the gears. Runout is a radial phenomenon, while accumulated pitch variation is a tangential characteristic that causes transmission error. Gears function tangentially. It is also possible to have a gear with accumulated pitch variation, but little or no runout.

200 Industry News (March/April 2019)

The complete Industry News section from the March/April 2019 issue of Gear Technology.

News Items About CTI Symposium USA

1 SMT to Present Paper at CTI Symposium USA (May 5, 2016)
SMT's Baydu Al will be at the CTI Symposium USA in May to present his paper, "FEA of Tooth Flank Fracture (TFF) Using Boundary C... Read News

2 Oerlikon Presents Paper at CTI Symposium USA 2017 (May 23, 2017)
High-performance transmission specialist Oerlikon Graziano, brand of Oerlikon Drive Systems Segment, presented its range of hybrid transm... Read News