Quality Scan: Portable Metrology Certification
From product development to in-place inspection, manufacturers—large and small—have incorporated dimensional-inspection processes to maintain product design intent and ensure quality parts. And with the advent of portable CMMs such as articulating arms, laser trackers, and photogrammetry systems, these instruments have become simply another tool in the toolbox of metrologists, toolmakers, service companies, and a never-ending list of entrepreneurs. Over the past ten years, the number of PCMM operators has grown exponentially.
How does an employer or contractor know if an operator is truly trained and has the necessary expertise to choose the proper piece of metrology equipment, then commence to capture data that is accurate, correct, and repeatable? How can the small job shop find the right metrologist for its type of work? Industry has expressed the legitimate concern that a certification program is needed.
In the past year, a subcommittee of the Coordinate Metrology Society has been collecting data, processing survey results, and outlining a proposal for a certification program. This query was also posed to over 200 workshop participants at the Coordinate Metrology Systems Conference—also known as CMSC—which is held by the Society, whose members are proficient in various fields of industry relative to coordinate metrology.
Certification of operators has been a lingering concern among many professionals for more than a decade. Why the push for certification now? After all, conventional CMMs have been a mainstay as the final word in coordinate inspection for many years.They seldom, if ever (along with the operator), faced questions about validity of the results of coordinate inspection. As long as a NIST traceable artifact could be accurately repeated, life was good. Because of the need to have a controlled environment, granite table, and dedicated space for a conventional CMM, the number of operators was regulated by the number of machines in the workplace.These operators, especially in large companies, were trained and "certified" according to their own company's guidelines. The self-employed CMM operator was virtually nonexistent.
In this sense, it seems the certification of an individual would prove, in some manner, that the operator possesses the knowledge to competently acquire and process 3-D coordinate data. After all, the equipment being used is certified to exacting specifications and traceable to NIST standards. So why not certify the operator and close the circle, as it seems simple enough?
The discussion on this topic at CMSC brought forth pros and cons from attendees. The collected CMS survey data overwhelmingly support a program for professional certification. The outcome of this program, many feel, would be highly beneficial not only to the recipient of these services, but for the providers of these services as well. But why were there naysayers at the conference?
Developing a certification program capable of achieving national and possibly international acceptance is a daunting task. Some survey participants believe that certification will translate to more bureaucracy and complexity, especially at large companies where unions, structured levels of management, and silos are already in place. Others expressed concern that without the support of the large corporations who dominate the purchase and utilization of portable metrology equipment, accreditation or certification on a national level won't take root, and therefore will not have merit.
In the end, is the cost associated with acquiring and maintaining certification for these operators justifiable? Based on the wide range of measurement systems and the availability of even more software platforms, it doesn't take long to realize that complexity is certainly a justifiable concern.
The Coordinate Metrology Society will continue to deliberate these important issues in the coming year.We are very interested in feedback from metrology professionals, and encourage you to weigh in on the topic of certification by emailing your thoughts to Chairman@CMSC.org.
With or without accreditation or certification, there is one characteristic that should be universal to all metrologists. We must possess the very highest ethics in the collection and post processing of digitized data. This is one point that is not open to challenge.
This article was first published in the February 2010 edition of Manufacturing Engineering magazine.