Shop floor metrology equipment is getting faster, smarter, and more automated. Is it time for an upgrade?
Initially, this article was going to explain how machine shops and moldmakers could sell all of their handheld measuring tools and gages and replace them with shop-hardened coordinate measuring machines (CMMs). Gone would be the time and expense of managing hundreds of micrometers, dial indicators, bore gages, and other metrology gear found in a typical shop’s inspection lab, all of it made obsolete by a single multifunctional device capable of measuring anything that fits within its volumetric area.
Fat chance, right? Apparently so. Gene Hancz, CMM product manager at Mitutoyo America Corp., Aurora, Ill.—one of the few metrology equipment providers that still makes hand tools—will tell you the company still receives orders for old-fashioned vernier-style calipers. It seems that some habits are hard to break.
Still, it’s a grand vision, and even though that glorious day may never come, there’s no argument that CMMs are growing very capable. So is the software that drives them, not to mention the cameras, laser scanners, surface finish probes, and other attachments that give meaning to the “multifunctional” term used now. Your shop might not be one of those that still rely on vernier calipers, but if you took delivery of your CMM sometime during the Bush era, or are looking for ways to decrease the cost of quality, it behooves you to keep reading.
When not expressing chagrin over the continuing use of vernier calipers, Hancz explained that Mitutoyo recently introduced upgrades to several key products, among them an “overall renewal” of its CMM line and Version 5 of the company’s MCOSMOS metrology software. With that is MiCAT Planner, an automated program generation tool, signifying an increased focus on the manufacturing community’s embrace of Industry 4.0, the Industrial Internet of Things (IIoT), and digital twins.
Mitutoyo is not alone. Each of the metrology providers interviewed for this article described similar technology updates, all designed to make CMM programming and CAD integration both simpler and more seamless. They also spoke of an industrywide push for automation, both in the programming and operation of measuring equipment. Said Hancz, “Manufacturers are looking for these and other advanced capabilities to help offset the severe shortage of skilled workers.”
One of these is support for model-based engineering (MBE) and product manufacturing information (PMI), which allows engineers to include geometric dimensioning and tolerancing (GD&T) requirements in their CAD models. Doing so makes what has long been viewed as a ime-consuming, tedious process—CMM programming—into a largely automated affair.
Hancz referred to this as the “stop programming, start planning” approach. “If you present us with a CAD model that contains comprehensive and accurate PMI data, we can literally generate a complete program within minutes. You can then simulate the measurement plan, make whatever adjustments might be needed, and send it to the shop floor. Previously, that same job might have taken a couple of hours, maybe longer depending on the part complexity.”
Capabilities like this are becoming widespread, not only in the inspection room but the CNC programming office as well. David Wick, manager of product management at Zeiss Industrial Quality Solutions, Maple Grove, Minn., noted that shops can easily cut their CMM programming times by upwards of 80 percent through the use of PMI-equipped CAD files, while also eliminating any human errors. The challenge, he said, is getting more OEMs to include GD&T information in their models. “It’s used heavily in the aerospace sector but has yet to enjoy widespread adoption in other areas.”
PMI or not, Wick echoed what others stated here with regard to CAM software usability. “Everybody seems to be making their metrology inspection software both easier to use and faster to program, so that even a novice who’s never used a CMM can quickly learn it and start measuring parts in less time than ever before.”
The focus is on productivity, he added, suggesting that recent updates to the company’s CALYPSO 2022 measurement software have made it possible to measure more parts per shift than in previous versions. One of these updates is related to its VAST gold contact scanning probe. As with similar systems, VAST lets an operator quickly capture hundreds or even thousands of consecutive points on part features and surfaces. Once the process is stable, however, CALYPSO allows the user to “tweak a parameter” and thereby reduce the number of measurement points, thus optimizing the program and saving time.
“This is just a small example of ways that customers can reduce measuring time,” he said. “More and more, shops are evaluating CMM throughput and looking for ways to improve it. It’s important here to recognize, though, that there’s more to speed than how many data points you can gather per nanosecond or how fast you can change a probing head. A savvy customer will say, ‘What’s the entire elapsed time, from the moment I import the CAD file to the time I have the inspection report in my hands and I’m moving on to the next job.’ They’re going to look at the efficiency of the entire workflow. That’s what best determines throughput.”
Wick and Mitutoyo’s Hancz also mentioned an increased call for more traditional forms of automation. The latter described how manufacturers are installing conveyors and robotic arms on its MiSTAR series of shop-hardened CMMs, while Zeiss sees similar activity on its DuraMax line. Both have a three-sided open architecture, a working temperature range of 10° C to 40° C (50° F to 104° F), and can be equipped with pallet systems for loading and unloading.
So does Hexagon Manufacturing Intelligence, North Kingstown, R.I. Ryan Toole, Hexagon MI’s product manager for automated measurement systems in North America, noted that the TIGO SF is first on the company’s list of shop-floor CMMs. He also pointed out that many customers are equipping them with an “off-the-shelf” loading system similar to those seen on a growing number of CNC lathes and machining centers.
“The TEMPO is equipped with a Universal Robot and a series of drawers that you can fill with parts,” said Toole. “You don’t have to stand in line or wait for the CMM to finish what it’s doing—you just put your part or pallet of parts on the loading system and walk away. Granted, the CMM still has to go through its measuring process, but all of the loading and sorting is taken care of by TEMPO. And since the robot is collaborative, there’s no need for safety fences.”
For lower volumes, Toole described the ability to place a part on a measuring fixture—robotically or by hand—and have the system recognize the workpiece, call up its measuring routine, automatically align and then measure it, all without operator intervention. Doing so requires that the part has already been programmed, obviously, and that identifiable features exist, but it eliminates the inspection bottleneck that so often occurs and allows even very inexperienced users to measure their parts.
Then there’s integration with CNC machine tools. Toole explained that, whatever the CMM or its probing system, the resulting data can be fed into Hexagon’s QDAS IMC software. “Q-DAS is then going to analyze it and begin making suggestions, and depending on what that particular organization wants to do, can start making changes automatically to a manufacturing process,” he said.
The notion of a CMM giving instructions to a CNC machine tool is both exciting and a little scary. According to the company website, Q-DAS IMC “enables clear communication between machine tools with Siemens, Fanuc or Heidenhain controllers and the Q-DAS database. It can manage different machine tools, measuring projects and feature information.”
Dan Skulan isn’t scared. As the general manager of industrial metrology at Renishaw Inc., West Dundee, Ill., he has no quarrel with using automated gaging for direct process control, even if it’s with one of the products mentioned so far. Yet he’d much prefer that shops utilize a Renishaw metrology solution, whether it’s one of the company’s in-line probing systems or its Equator gaging system.
Skulan is quick to point out that the Equator is not a CMM. Rather, it is a “highly repeatable, error-mapped comparative measuring device” that works on the same basic principle as a micrometer or bore gage—namely, it must be calibrated against a known artifact before use. This makes it largely immune to the temperature fluctuations seen on a typical factory floor, and thanks to its parallel kinematic design, the Equator is also highly rigid, an attribute that makes it quite fast.
“To achieve the greatest accuracy with the Equator, you want to calibrate it with a master part that’s been measured in a controlled environment and is therefore traceable,” he said. Because of this, it’s probably best suited for higher-volume or repeat work. But in these applications, we have customers measuring part tolerances down to eight microns and at speeds nearly ten times faster than a CMM, and they’re doing it right on the shop floor. The machine constantly monitors the temperature, and if it changes by more than a predetermined amount, you just put the master part back on the stage, zero it out, and get back to work.”
As his job title suggests, Skulan is enthusiastic about industrial metrology. He’ll tell you the Equator is but a small piece of an optimized factory strategy, one that starts by establishing machine tool accuracy and health verification. With this comes automated setting of tool length and workpiece coordinates, adaptive machining, automatic gaging via the Equator or a similarly robust solution, and direct measurement on the CNC machine tool whenever possible.
Each of these is part of a process control framework that also includes a “fast, 5-axis multisensor technology” called REVO—a CMM probing system that, according to Renishaw, can be adapted to any make or model of CMM, greatly increasing its output as a result.
Skulan explained that any mechanical system will bend and twist when accelerated through a curve. This introduces positioning errors that, in the case of a CMM, limit its speed. REVO is no different except that it’s very rigid and lightweight, so there’s minimal deflection. In addition, the system uses an internal laser to measure the location of the probe tip in real-time as it moves, so it can scan at surface speeds up to 50 times faster than traditional CMMs without any loss of accuracy. “Where the Equator addresses the problem of inspection backlogs during ongoing production, REVO solves the first article backlog,” he said.
Emily Rapp and Caitlin Considine are technical marketing engineers for quality and metrology systems at Keyence Corp. of America, Itasca, Ill. They agree with what Dan Skulan said about the benefits of measuring directly on the CNC machine tool, but their approach is significantly different. “With our new XM-5000, you can take the camera unit off, mount it on a pole or tripod, and bring it to the machine or work area for part inspection,” said Rapp.
Keyence defines its XM series as a “handheld probe coordinate measuring machine.” As the name suggests, it uses a high-resolution camera to triangulate the movements of a handheld touch probe. An operator removes this device from its cradle and follows the instructions on the augmented reality display to begin measuring in three dimensions. As with other CMMs, the XM has file import capabilities, generates quality reports, and collects data for statistical purposes, but it can also record images of the workpiece during inspection.
At first glance, it seems improbable that a handheld probe moving freely through space, its position tracked only by a camera, can offer any level of accuracy. Rapp said the proof is in the pudding. “We hear that a lot, but once a customer sees an onsite demo and understands how the system works, they quickly become believers.”
She’ll also tell you that the XM brings significant value to the shop floor. Because operators can quickly check a feature or even run through an entire inspection routine without removing the part from the machine, downtime is reduced and there’s less chance for scrap. However, Rapp is quick to point out that the XM can be used as a traditional CMM, albeit one that’s much more mobile and flexible.
Considine seconds those views, and points to a different Keyence device—the IM-8000 Automated Optical Comparator—as yet another measuring system that meets the industry’s call for faster, easier-to-use metrology equipment. “The IM is a direct replacement for the optical comparator found in most shops, but its capabilities are much greater,” she said. “For instance, it has CAD import capabilities, can measure all two-dimensional features as well as heights, and now has an option for a rotary unit. The IM is also largely automatic. You can fill the stage with parts and it will not only find them all but measure up to 300 features within a few seconds. It’s a huge timesaver, especially for shops that have to inspect a wide variety or high volumes of parts.”
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