Every so often I receive a panicked request to provide training in dimensional metrology, or the name of someone who can do it when I’m not available. The urgency of the request is the first clue that someone is in damage control mode.
Invariably such requests are the fallout from a quality audit-a finding that has to be fixed in 30 days or so, if it can be.
Another situation that leads to such requests involves corporate takeovers. A number of processes are applied that include integration, merging and resizing, which usually means expensive, skilled employees are put out to pasture in favor of unskilled, lower-cost newcomers.
Panic requests for training usually note that it must be at the customer’s plant and not take more than a half day or so. Basically what is wanted at the end of it all is a warm body that can read an instrument and little more. Oh, don’t forget, each student will require a certificate. It’s rather like training a neurosurgeon in one easy lesson without getting complicated.
Technical colleges offer basic training courses, but whether they can meet these requirements is a bit iffy. Still, if you are in such a situation, you should check them out. Discuss your needs with the instructor so everyone is singing from the same sheet music.
If you intend to set up your own in-house training program, here are some considerations beyond how to read a micrometer:
Make sure the students can speak the language. By this I mean part feature talk: counterbore, through hole or bore, datums, center-line, blind bore, center-distance, squareness, chamfer, run-out or TIR, keyway, slot, width, length, diameter, and inch and metric units of measure.
Ensure students understand some metrology basics. Examples would include, compare, accuracy, repeatability, linearity, master, standard(s), zero-setting, offsets, taper, roundness, range, capacity, tolerance, co-efficient of thermal expansion, measuring force, traceability, calibration, surface texture or finish, taper, ovality, parallelism, roundness, lobing, flatness and resolution to name a few.
If your company makes, buys or inspects threaded fasteners, elements of screw threads will have to be explained. Examples would include major, minor and pitch diameter, linear pitch, half-angle root, crest, classes of fit, thread wires and threads per inch.
Knowing how the instruments actually work is worthwhile so those using them have some idea where to look when things go off the rails. Simple explanations along with sources of errors when they are used can save a lot of problems in their use and help the instruments gain the respect they are entitled to.
That would be my shopping list for folks checking component parts. I couldn’t cover it all in a day and I doubt anyone could absorb most of it, even if I could.
Having “trained” your staff as noted above, one thing you’ll have to do is test them to see if they have acquired the skills necessary to take the measurements. The easiest way to do this is to give them items of known dimensions and see how closely their measurements match the known or calibrated values.
You may want to use a couple of sample components for this purpose. They don’t have to be correct dimensionally since you are going through a comparative process. Rejected parts can be useful after all. Just keep them labeled so they don’t get mixed up with good parts. Some gages that have been rejected also can be used for such testing, but if they are badly tapered or out of round, you may have to mark the measurement locations so their geometry doesn’t mess things up. In some cases, you may want to use components with geometrical irregularities to see if your students find them.
Needless to say, all of these activities should be recorded so an auditor can see that you have actually trained your people and the subjects and skills you taught them.
Over the years I have taught classes in metrology and noticed that most people that are given the opportunity to learn more tend to want to do so. This attitude can be quite rewarding for the teacher, particularly when you see the pride when your charges master new skills and understand more about what their job entails.
