Metrology Makes Education a Priority
Metrology technology has taken huge strides in capability. Industry professionals are finding that training and certification need to keep pace as technology advances
By Bruce Morey
Newer technologies like laser scanners and structured light devices measure millions of high-quality data points within seconds. Although not as data rich, older technologies like CMMs equipped with probes, are more capable than ever, with multiple axes of freedom and advanced probes, requiring sophisticated parts programs. Portable arm CMMs and increasing use of automated metrology are also both a boon and a challenge. Not to be ignored, hand tools remain in demand, with their inherent repeatability issues.
In such a complex measuring environment, it is no longer a straightforward task for humans to interpret the resulting data.
This is borne out in the experience of Pat Walsh of the consulting firm MVS Group (Southfield, MI). He works extensively in automotive body panel applications and tooling. He found that when his applications began using structured ‘white light’ scanners, the resulting flood of data solved some problems and introduced new ones. In body panels with smoothly varying compound curves requiring sub-millimeter accuracy, using data from CMMs equipped with touch probes “is like watching a football game with only 12 pixels on your TV showing,” as he explained it. While individual points are quite accurate, it is difficult to make sense of the whole ‘game.’
“When we started using white light scanners such as those available from Cognitens or ATOS, we did not have to do extensive analysis. Simply by looking at the color maps, engineers were able to draw conclusions about deviations in their parts,” he explained. However, he soon realized that different organizations and companies, such as OEMs and suppliers, were registering scan data to CAD in different ways, leading to varying results. “We found people had vastly different ideas about how to register scan data to meet GD&T requirements,” he said, with different interpretations on what meeting the standard meant. He believes a lack of emphasis in basic engineering curriculums is one element contributing to the confusion. More education and certification from organizations, such as the Coordinate Metrology Society will help create a unified approach to the growing problem.
As important as knowledgeable, trained personnel are, not every company feels it can afford to make training a high priority, according to Eric Hayes, director of software applications for Nikon Metrology (Brighton, MI). “This seems to be especially true of smaller companies, who are getting squeezed for profits,” he explained. While acknowledging that is not a majority of companies he deals with—maybe 15–20% by his estimation—it is a growing problem. Often, end users who fall into this category might end up using customer support phone lines more than anticipated. “But the reality is, we can’t train people over the phone,” he said.
Nikon Metrology offers two types of training to its customers, a customized on-site course and classroom-focused training at its facility in Brighton, MI. “The advantage of the on-site course is that we can find what they need, and train using their equipment in their facility,” he said. The advantage of the training course in Brighton is that it tends to be more cost-effective as well as more general in nature. Courses include GD&T basics, DMIS 5.0, CAMIO software, and CMM Manager software training. “We do offer web training customized to what the customer wants, and that is the most economical, though not quite as effective as hands-on training, showing people how to measure real parts to real datums,” he said.
Software, Training, and Choices
“There is always a gap between what is measured, recorded, and displayed and what is interpreted by people. There are two ways to close that perception gap. The first is to make software easier to use and more interpretable. The second way is to make people themselves more capable through training,” said Brian Gudauskas, national applications and support manager for Hexagon (North Kingstown, RI). Even the most sophisticated data reduction software will not overcome a lack of basic understanding of metrology and GD&T. He believes there is a clear need for more trained metrology professionals.
“What made us recognize the need for training is that when we started our Hexagon Metrology Services division, we were swamped with orders almost immediately,” Gudauskas explained. “Some of our customers wanted us to take over their quality labs.” Why? They simply did not have the trained, capable staffing available. “Our customers are only successful if, when they purchase our machines, they are able to use them effectively,” he said.
It was clear their customers needed more trained personnel. In response, Hexagon developed Hexagon Metrology University. The company announced it to a national audience in June 2013. In some ways, Hexagon Metrology University is taking up where engineering and technical schools leave off. “There is no question that there is a basic lack of metrology education in the engineering curriculum,” Gudauskas said. He also noted that while metrology is sometimes considered a niche profession, the demand for trained, knowledgeable metrologists is increasing. The company also observed that as more students started taking equipment specific training courses, they arrived without a basic background in metrology, including GD&T. “Teaching people how to use metrology equipment without metrology basics is a very difficult class to teach,” he said.
He reports demand for their training is high, in excess of their classroom training. Each class is limited to 10 seats by design to ensure quality participation. To meet the higher demand, Hexagon developed on-line training that covers the basics of equipment such as portable arms, lasers, and CMMs and basic metrology theory.
Certification for Portables
Randy Gruver is a portable metrology training professional with Boeing (Seattle, WA) and chair of the CMS Certification Committee for the Coordinate Metrology Society (Benbrook, TX). He was instrumental in developing a brand new certification through the CMS. He points to a few of the motivations behind their Level One Certification program, and their Level 2 certification for portable arm CMMs, which was first offered in July 2013. “First, metrology requirements are increasing,” he said. There is a transition underway from a niche core of metrology professionals in the past to much broader applications in the manufacturing world. “Folks that are now tasked with using metrology equipment are less inclined to be experts with an engineering background,” he said. This is doubly true with increasing automation. Especially in the aircraft world, metrology has transitioned into enabling what he terms ‘determinant manufacturing,’ enabling less tooling and more metrology-assisted assembly.
“While the equipment, software, and hardware were so capable of performing so many amazing measurement operations, we felt that the operators were getting left behind,” he said. “It was difficult for an operator to stay abreast of the technology. There was no credential or way that an operator could develop themselves professionally, to stay on top of the industry, and the certification seems to play well into that.” A certification program would both legitimize the field and help qualify who was capable of operating effectively in this new world.
The second reason was pressure from the industry itself, in the growing body of third-party service providers and their customers. “For instance, the nuclear industry requires credentialing of professionals who perform contract work, but for metrologists, that did not exist,” he said. Now, at least for portable CMMs, it does.
Initial certification requires two years of experience in the field. There is also a peer review, and an applicant is required to provide four references, according to Gruver. Those references receive a letter asking for specific information on aptitude and ethics. A written, proctored exam with 196 questions is then offered to qualified applicants (for more information on the exam content, see http://www.asprs.org/CMS-Certification-Program/Examination-Matrix.html.)
Gruver predicts that by the summer of 2014 there will be more study guide and commercial training materials available. He also reports that the CMS is working towards Level Two certifications that will be performance based for Laser Tracker and Structured light scanners which will complement the Level 2 (performance) exam for the PCMM.
CMM Certification—Germany Weighs In
Another form of certification, this one aimed at stationary CMMs, are the three levels of AUKOM certifications. The AUKOM certifications (Ausbildung Koordinatenmesstechnik e. V.) were developed in Germany and are available exclusively in the USA through Zeiss Industrial Metrology (Maple Grove, MN). The training includes basics of CMMs, current best practices, and metrology concepts. Although offered by Zeiss, the certifications are not tied to proprietary equipment.
Each certification level requires an exam. Each certification level is then recognized internationally. Level I training is aimed at training basic users, who have no foundational knowledge in metrology, Level II at creating competent operators, and Level III at expert users capable of managing a measuring room equipped with a CMM. Level II certification can have alternative sensor-dependent focus on three sensor types: tactile sensors, image-processing sensors, or distance sensors. Recognizing the complex world in which CMM operators live, AUKOM content includes topics from basic metrology practices, feature geometry, coordinate systems and CAD programming considerations to influences on measurements from manufacturing engineering, CMM components, software functionality, quality standards and statistics.
Aliesha Anderson, applications customer education manager for Zeiss, is responsible for the company’s training program. “It was recognized in Germany around 1998 that industries were missing a large amount of knowledge surrounding quality inspection and metrology,” she said, explaining the motivation behind developing the AUKOM training. The ad-hoc nature of typical CMM training, including on-the-job training coupled with some equipment-specific was not maximizing the potential of measurement professionals. “Operators need to go beyond the results the machines are producing to understanding why they are getting the results they receive,” she explained. “They need to know why they are measuring and if something is off, know or determine why it is off.”
According to Anderson, AUKOM bridges a gap between what apprenticeship programs teach and how operators actually use CMMs. Training is in physical classrooms, via discussion and lectures, according to Anderson.
Career Possibilities—Metrology Engineering
“There is a lot of sophisticated equipment out there these days,” agrees Dr. James Salsbury, manager of the Mitutoyo Institute of Metrology, a training unit of Mitutoyo (Aurora, IL). He also agrees that today’s equipment requires a more sophisticated user. “We are at a major point of change with a lot of the newer technologies.” However, perhaps paradoxically, he also reports that hand-held metrology equipment, such as calipers and micrometers, are still active sellers. Both require education. “There are a lot fewer people who understand how to use the basic measuring tools to employ proper metrology,” he said.
He reports that the Mitutoyo Institute’s basic Dimensional Metrology course has been popular recently, a course that reflects the basics required in the industry today. “Some of our most popular are calibration related courses. People want to come and learn how to calibrate their hand tools, gage blocks, or height gages,” he said. His group also teaches an integrated GD&T course, focused more on the measurement side of GD&T and designed for the measurement professional.
Another important issue in the field, he says, is the fact that “GD&T is a hugely misunderstood field.” He believes there is a gap between the tolerances design engineers put on prints and how metrologists can measure them. This is especially important when measurements are related to performance attributes, like emissions that might be caused by wear in engines. “The product designer should know enough of the basics of metrology to know how to specify GD&T correctly,” he said.
He points to a future where metrology as an engineering discipline will evolve, solving some of the problems of disconnect between specified tolerance and measurement capability. Since metrology is woven into everything that manufacturing does, it is time to recognize it.
“I tell my students that the more exciting metrology jobs of the future are not as a CMM operator, but an engineer who programs and deploys measuring strategies across a manufacturing process,” he explained. “They will employ automation, platforms of CMMs, and CAD integration. This is a very different kind of job description. It is not someone programming or manually teaching a CMM how to measure, but a much more sophisticated individual deploying technology into manufacturing.” ME
This article was first published in the January 2014 edition of Manufacturing Engineering magazine. Click here for PDF.
Published Date : 1/1/2014