These are changing times for industry. Trauma and uncertainty are always a part of change, and change is not always for the better. Change is usually forced, most frequently by competition. Our competitive free enterprise system should be able to respond to competition because that's its basis. These are critical years. If we do not respond effectively to change and competition, it could be disasterous.
In conventional gear grinders, grinding wheels with Alundum grains and a hardness of about 2000 HV have been used for finishing steel gears with hardnesses up to about 1000HV. In this case, the accuracy of the gears ground is greatly affected by wear of the grinding wheel because the difference in hardness is comparatively small when the gears are fully hardened.
Since we are a high volume shop, we were particularly interested in Mr. Kotlyar's article describing the effects of hob length on production efficiency which appeared in the Sept/Oct issue of Gear Technology. Unfortunately, some readers many be unnecessarily deterred from applying the analysis to their own situations by the formidabilty of the mathematical calculations. I am making the following small suggestion concerning the evaluation of the constant terms.
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.
Sub: 'Finding Tooth Ratios' article published in Nov/Dec 1985 issue
Let us congratulate you and Orthwein, W.C. for publishing this superb article in Gear Technology Journal. We liked the article very much and wish to impliment it in our regular practice.
The following is a general overview of some of the different factors that lead to the specific design. and the selection of the correct tool for a given hobbing application.
The proper design or selection of gear cutting tools requires thorough and detailed attention from the tool designer. In addition to experience, intuition and practical knowledge, a
good understanding of profile calculations is very important.
Hobbing is probably the most popular gear manufacturing process. Its inherent accuracy and productivity makes it
a logical choice for a wide range of sizes.