How Do You Make the Perfect Gear?

摘要

Okay, I'll admit it. It's a trick question, because of course there's no such thing as a perfect gear. There will always be manufacturing errors, inconsistencies and human error. Tools and machines wear down, so that the first gear you produce will always be different from the one hundredth. Every time you change a tool or clamp a new workpiece, you introduce more opportunity for error. And those errors all stack up: machine, tooling, workholding, gear blank, etc., are all in a constant state of change throughout a manufacturing run, whether we're talking about a single piece or 10,000. So you can't make a perfect gear. But even if you could, you would never know, because you can't measure one, either. Inspection equipment is made up of moving parts, so it's subject to the same problems as manufacturing equipment. When you introduce other variables - like the temperature of the room or the part being measured - it becomes clear that not only can you not measure a perfect gear, but neither can you measure an imperfect one the same way twice.