November/December 1989

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Feature Articles

Technical Articles

Systematic Approach to Designing Plastic Spur and Helical Gears
Plastic gears are being used increasingly in applications, such as printers, cameras, small household appliances, small power tools, instruments, timers, counters and various other products. Because of the many variables involved, an engineer who designs gear trains on an occasional basis may find the design process to be somewhat overwhelming. This article outlines a systematic design approach for developing injection molded plastic spur and helical gears. The use of a computer program for designing plastic gears is introduced as an invaluable design tool for solving complex gearing equations.

Hard Finishing and Fine Finishing Part 2
After shaping or hobbing, the tooth flanks must be either chamfered or duburred. Here it is paramount that the secondary burr produced will not be formed into the flank, but to the face of the gear, because during hardening, the secondary burr will straighten up and, due to its extreme hardness, will lead to excessive tool wear.

Compter-Aided Spur Gear Tooth Design: An Application-Driven Approach
This article discusses an application driven approach to the computer-aided sizing of spur gear teeth. The methodology is bases on the index of tooth loading and environment of application of the gear. It employs handbook knowledge and empirical information to facilitate the design process for a novice. Results show that the approach is in agreement with the textbook data. However, this technique requires less expert knowledge to arrive at the conclusion. The methodology has been successfully implemented as a gear tooth sizing module of a parallel axis gear drive expert system.


Editorial (Publishers Page)
Mission: Competing to Win Like a lot of people, I grew up seeing the world as fairly flat and believing that everything of importance happened in Texas. As I grew older, my outlook grew to include the United States, Canada, and Mexico. The rest of the world did not seem very important, if it existed at all. Unfortunately, I was not alone in this very narrow view. Many other in the gear business shared this perception.

Editorial (Publishers Page)
The press release on my desk this morning said, "The (precision metal working) industry cannot attract enough qualified applicants. As many as 1,500 jobs a year (in the Chicago are alone) are going unfilled." So what else is new? That's just hard proof confirming the suspicion many of us have had for some time. Some of the best, most qualified and experienced people in our shops are reaching retirement age, and there's no one around to fill their spots. And, if the situation is bad in the metal working trades in general, it's even more critical in the gearing industry. Being small and highly specialized, gear manufacturing attracts even less attention and finds recruitment harder than the other precision metal trades.

Technical Calendar (Events)
Complete technical calendar for November/December 1989