Quality assurance

Manufacturing Engineering, Aug 2002

Manufacturers continue making progress in their quest to move measurement systems out of controlled metrology laboratory environments onto the factory floor. In addition to installing more shopfloor measurement systems, quality assurance advances in software, noncontact probing, open architectures, and continued cost/performance improvements are spurring technical innovation in the field.

VISITORS TO IMTS WILL SEE a range of new systems and software aiming to bring metrology closer to the shop floor, and improve manufacturing quality and process controls. With increasing demands for greater tolerances and higher quality, manufacturers are turning to inprocess gaging, engineered solutions, and much more accurate measurement equipment in order to meet customers' needs.

"If you're looking at plastic injection molding houses or at traditional metalworking applications, those guys are still working in the 0.0001 " [0.003mm] range for accuracies," says Mike Cognac, general manager, Metrology Systems Division, at L.S. Starrett Co. (Athol, MA). "While at one time that was a pretty tight tolerance, it's not anymore. Things are getting smaller, accuracies are getting tighter. As we move forward we have to do a progressively better and better job of making our machines tight enough to meet those requirements."

Advances in machine construction and more sophisticated software have helped metrology suppliers design more accurate systems. "We're moving towards making products that are easier for an operator to use, so that he can get through the measurement more quickly," Cognac notes. "We're trying to attain more accuracy in the actual mechanical design, and the software of the machines that are used to measure." Manufacturers of CMMs and other measurement systems can achieve that goal by using the most stable materials, such as hollow granite, Cognac adds, that will ensure a stable environment that stays within specifications.

Process control through advanced measurement systems on the factory floor increasingly has become more important to automotive suppliers, according to Robert Sand, president of Mitutoyo Engineered Systems (Mason, OH), a subsidiary that Mitutoyo acquired early last year when it was called Nelson Precision Inc. "We've seen that over the last probably three to five years," Sand says, "but now more than just getting the equipment into the manufacturing environment, we have to provide data that enhances the manufacturing process. That's the big change now, that these quality tools are actually being used as process tools.

"When we sit down with Toyota, General Motors, Ford, or any of their suppliers, they want us to show how their investment in a measurement machine will enhance their manufacturing process," Sand adds. "They want us to show how it reduces cost, increases output, and where that technology will improve product quality."

At IMTS, Mitutoyo Engineered Systems will be showing its Sure Shot line of measurement products aimed at automotive applications. "We are taking surface texture analysis from the laboratory right into the manufacturing world," adds Sand. "Through a whole series of tools and concepts, this will allow virtually anybody that generates a surface to make a high-quality measurement at the manufacturing site."

"From the engineered systems point of view, that's probably the first and most important thing," he adds. "We're also integrating this with agile machining processes. Agile dimensional metrology is the second phase, and we're just finishing three machines that have the capability of working with and complementing an agile machining process. This will be available next year, as a process-control tool."

Software, noncontact probing, and open architecture are among some of the key trends currently shaping the measurement sys] tems industry, says Brown & Sharpe Inc.'s (North Kingstown, RI) David Genest. "Software continues to be the real driving force behind what customers need and want," Genest says. "They tend to be making software decisions, as opposed to hardware, when they purchase CMMs.

"Noncontact probing is starting to get quite reliable and quite accurate, and that's a big change," he adds. "There's a tremendous amount of work being done there, and with that comes a lot more points to process, so the software has to change. And with open architecture, there are lots of very powerful standards organizations working on standardizing all of the various interfaces in the CMM: between the controller and the machine; between the software and the machine; and between the probe and the machine. There are noncontact and tactile organizations working on standards, and there are some big changes coming in that area to allow customers more flexibility on what they buy-and how they assemble the pieces together."

Among its IMTS announcements, Brown & Sharpe will show its new DCC Gage Measurement Station, an entry-level CMM that includes Brown & Sharpe's new updated PC-DMIS Pro V 3.5 software. "The PC-DMIS software supports a wide variety of noncontact sensors and solves the nagging problem in the past, where the sensors required a second piece of software and computer," Genest adds. "Now, the noncontact sensors are going to be integral to PC-DMIS."