I’m sure we can all agree on one thing. Delivering a quality product is priority #1…or at least that’s what we say and we really mean it! Then why is it that so often the people charged with the huge responsibility of determining the ultimate quality of the final product, are lacking the proper training required to carry out this duty? I’m referring specifically to CMM inspectors.
Let’s consider that the vast majority of CMM inspectors out there have received their training on-the-job. If you’re one of the very lucky few, you were trained by someone who really knows their stuff and has been at it for a while. If you’re one of the unlucky, you received little or no training and are left to learn on your own. Sure, you can get training in the specific CMM software you will be using, but that alone is like learning how to operate a car and having no idea what any of the road signs mean…a recipe for disaster for sure.
A CMM is an inspection tool, but unlike most inspection tools, the results obtained on CMM’s are not so clear-cut and very easy to misinterpret. It’s easy to select a measurement from the software, probe a few points and attain a number, but is it the number you’re looking for? What exactly is the drawing asking for? Did you take the appropriate amount of points, in the appropriate locations? Apply the correct calculation for the geometry being measured? Filters? You get the picture. There are so many more factors to consider in being confident in the values attained.
Whether you fall into the lucky or the unlucky group, you perform your duties to the best of your abilities. “You know what you know and you don’t know what you don’t know,” operating inside a bubble and you’re point of view is all you have. You can imagine how nerve-racking it is for a CMM inspector to make a call on whether parts conform to specifications or not, when there is an internal conversation of uncertainty running in the background.
Running my own Metrology company since 2000 has provided me access to literally hundreds of companies in the manufacturing industry and it became apparent that CMM inspection, in so many cases, has become a self-taught skill. The danger in self-teaching is there is usually no one more experienced to learn from, and although one of the ways we learn is by making mistakes, you can’t learn from a mistake when you don’t know you’ve made one. Having access to someone more experienced is invaluable when learning a new skill.