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It's hard for some people to believe that twenty or so years ago coordinate measuring machines (CMM) ran on complicated programs such as Fortran and Basic, requiring operators to sit for hours punching in complex codes just to make them work. Over the years, CMMs have become increasingly user-friendly. Most CMM software packages now run on personal computers and use graphic user interfaces (GUI) that can be operated by individuals with almost any level of expertise.
As CMM software makes it easier for individuals of varying skill levels to get accurate measurements from CMMs, quality professionals are expanding the role of these machines.
One result of these changes is the migration of CMMs out of the laboratory and onto the shop floor. "There's a growing move to put CMMs into the production environment, in cells, in places where they're actually making chips." said Tony Aspin, sales engineering manager, CMM Div., L. S. Starrett Co., Atlanta.
"We're now selling as much to the production engineer as we are to the quality control engineers. That's a trend that is likely to continue as CMMs get easier to use and yet at the same time become more powerful," added Aspin.
One company using CMMs in everyday production is EST Co., a division of Leggett and Platt, Grafton, WI. EST manufactures diecast chair bases, furniture components, and precision, custom-diecast aluminum parts for a wide range of products, including gasoline-powered generators, motorcycles, and diesel engines.
EST has three CMMs manufactured by Brown & Sharpe, North Kingstown, RI, including a process control robot (PCR), which is a direct computer control (DCC) coordinate measuring machine that-automatically performs inspection routines. EST's PCR is used to measure diameters, machine bores, datum locators, machined dowel pin holes, and finished bore diameters, as well as flatness and the location of features such as through-bolt holes.
EST uses AutoFIT best fit alignment software from Automation Software, North Kingstown, RI, in conjunction with the PCR's Avail software program. AutoFIT automatically finds the optimal two-dimensional part orientation to ensure the best fit locations of the machined datums to the ascast hole patterns.
"We originally had what we called a 'tweak' program using the software that came with the PCR to adjust the machining operation based on the data that...