Training with Various Tools to Facilitate Measurement Instrument Selection

Abstract

The Purdue Polytechnic Institute in Columbus utilizes metrology tools with specially designed 3-D printed and machined measurement artifacts to facilitate learning and provide opportunities to demonstrate competency in basic measurement tools. Analog and digital calipers, analog and digital micrometers, Pi tapes, bore micrometers, and dial indicators are all employed during special training sessions designed to educate about various measurement tools, allowing trainees to develop knowledge on how to choose a proper measurement tool. Trainees and students use different tools to measure identical features on a part, highlighting the different scales, resolutions, potential errors and uncertainties, as well as the obvious ease or challenge to utilize each tool. There is an obvious advantage of digital dimensional measurement tools due to the ease of reading the value, but they may not always represent the best tool for the specific task. Little prior experience in measurement may lead to the belief that the value displayed on the tool is correct without considering appropriate procedures, units, and mechanics of actually using the tool – pressure applied to the measurement surface, proper zero-setting of the tool etc. In the case of measuring diameters, is there consideration and evaluation of using a two-point instrument versus a three-point instrument? These issues are highlighted only if different tools are used to measure the same feature. Another issue addressed is using a dial indicator for several geometric dimensioning and tolerancing measurements, such as flatness, parallelism, and perpendicularity. These procedures are demonstrated and participants will perform several of these measurements, discussing afterwards the value and utility of coordinate measuring machines.