Inspecting for Quality
Latest quality assurance equipment and software help improve manufacturing productivity
By Patrick Waurzyniak
Inspection and measurement systems are critical for shops to attain maximum quality from machine-tool equipment. At IMTS 2008, machine suppliers will show off the latest in quality assurance with machine probing, measurement, and metrology gear and software technologies that allow ultra-precise measurements for today's manufacturers.
Speeding changes in CMM part inspection, metrology supplier Renishaw Inc. (Hoffman Estates, IL) will showcase solutions that integrate inspection into manufacturing processes. "Renishaw at IMTS integrates revolutionary technologies to address driving trends in manufacturing—tighter process control [particularly Six Sigma], lean operation, and faster throughput," notes Leo Somerville, Renishaw Inc. president. "These forces are bringing pointed focus on quality assurance. Manufacturers seek to reduce and shorten post-process quality operations that add WIP burden.
"Complicating those efforts, they also need to produce and document parts to ever-higher precision," Somerville states. "That can mean more intensive CMM inspection—checking more parts, more often, checking more features, and taking more data points. Our company offers a solution to both less time and more inspection with the invention of ultra-high-speed five-axis CMM scanning."
At IMTS, Renishaw will display its Renscan5 scanning system, which combines multiple innovations to boost probe-scanning speeds from conventional rates of 5-15 mm/second to as much as 500 mm/sec, Somerville says. "CMMs can scan up to 6000 data points a second. Universal open-system design allows our Renscan5 application to run on both new CMMs and existing machines. This enables manufacturers to implement best practices across multiple plants and CMMs, while economically upgrading legacy machines to state-of-the-art performance. Automated five-axis scanning, an industry first, makes possible continuous part inspection without stops for part reorientation or stylus changes."
Faster inspection is especially vital on large, complex, high-value parts with many critical features, Somerville notes, stating that early implementers of Renscan5 in the automotive and aerospace industries have realized 300–900% reductions in their part-inspection times.
Technology convergence in metrology
is among the recent trends affecting the inspection and measurement industry, according to William Fetter of Hexagon Metrology Inc. (North Kingstown, RI). "Some trends that Hexagon Metrology have been seeing are both technical and tactical. Technically, we're seeing a lot of convergence of technologies—multiple sensors deployed on different hardware platforms; in some cases, the same sensor that can be switched between platforms [our ScanShark V4ix sensor can be used on either a portable arm CMM or a bridge CMM, for example], and inspection software that has common deployment across hardware platforms. PC-DMIS software can now be deployed on bridge, portable arm, laser inspection, vision inspection, CNCs, and laser trackers. The dream of a single CAD-centric software platform across all hardware technologies is finally becoming mainstream.
"The second trend is tactical. By that we mean companies are making tactical decisions with their metrology departments to outsource some or all of the function," Fetter adds. "For some companies, it's a matter of gaining expertise that doesn't exist in-house. For others, it's because of compressed launch schedules that the in-house team cannot complete alone. In either case, we're on top of this trend by offering a complete nationwide menu of services choices, from short to long-term. In some cases, we've partnered with a company to completely take over the metrology function in their facilities."
At this year's IMTS, Hexagon Metrology's theme is "Measure Your Dreams," notes Fetter. "We're helping our customers dream big and small in many ways with the new products we've launched in 2008. For example, customers with really big parts, the kinds that are impractical to move to a traditional CMM, have two new choices from Hexagon Metrology. Our Leica Geosystems division is showing the new Absolute Tracker, which is a complete redesign of our benchmark laser tracker. It still incorporates all the advantages of its predecessor, including a mature six-degrees-of-freedom wireless touch probe and hand-held scanning solution, as well as new features like a more compact size and lighter weight, faster startup, and greater accuracy."
The company's Romer division is showing its new Infinite 2.0 articulated arm portable CMM, which has more than a half-dozen new and improved features, according to Fetter, and enables people to perform inspection duties on just about anything, anywhere. "The Brown & Sharpe Optiv multisensor product line is for people with big dreams, but small parts to inspect. Featuring a combination of vision, laser, white light and tactile sensors, all powered by CAD-centric PC-DMIS Vision software, we're taking the dream of 3-D vision measurement and making it a practical reality."
In addition, Hexagon's Sheffield division will show a completely refreshed product lineup, including the thirdgeneration Discovery CMM for inspection stations right on the shop floor. Finally, for those who dream of more accurate calibration of machine tools and CMMs, the company's Hexagon Metrology Services, exclusive US distributor of Agilent Technologies' Dynamic Laser Calibration systems, will showcase the new Agilent 5530, which is smaller, lighter, and 20% more accurate than previous versions.
High measurement accuracy remains a critical technical trend, notes Jay Freeland, president and CEO of Faro Technologies Inc. (Lake Mary, FL). "Two trends are key, with the first being the continuing demand for higher accuracy," Freeland states. "To that end, last year Faro released three new higher accuracy FaroArms—the Quantum, Fusion, and Laser ScanArm V3, the last of which has noncontact ability as well—plus an all-new probe in conjunction with Renishaw called the Sensor.
"This year, the technology trend we're capitalizing on in the QA arena is toward noncontact measurement," Freeland adds. "We've released the Faro Photon Laser Scanner and Scene 4.5 scanning software, and bought the technology rights to Dimensional Photonics International Inc. (DPI, Wilmington, MA), which provides high-speed, high-accuracy digital shape scanners. Their technology is unique and well-protected.
"Basically, DPI uses a combination of lasers and cameras to create extremely accurate 3-D renderings of objects. We looked at a lot of similar noncontact technology, and this is by far the best. DPI's stated accuracy is 25µm. However, it has performed far better than that: at least equal to our current world-class FaroArm technology—without making any contact with the object it is measuring."
The technology ties to the measurement and optical expertise Faro already possesses, Freeland notes. "There are significant opportunities we have identified from an R&D standpoint," he says. "The hot points for this are aerospace and automotive—two markets we are already in—with good applications where they need very high accuracy, but also need to measure larger volumes. There may be some in the heavier manufacturing as well, where you are not talking about high-speed manufacturing processes. That's where we see the early stage use."
Another key trend is the advances in optical measurement, notes Jim West, Faro chief technology officer. "Optical measurement is a trend that's advancing rapidly, which as Jay notes, was one of the reasons why we were looking to develop the technology beyond what's readily available today," West says. "You'll hear a lot about 'white light' technology—meaning those using cameras associated with another object that creates a pattern to pick up the image—but our new technology uses lasers to create fringes, then measures the distances across the fringe as they move. It's the accuracy associated with it that makes a significant difference for many of the others out there that are nowhere close.
"The beauty of laser versus traditional white-light applications is that the laser focuses to infinity, so you can create high-accuracy measurements within a half-meter field of view," West states. "The key is that it's scalable in either direction, and that opens up a significant number of new opportunities for how our customers can measure. This laser-imaging technology is also very different from our existing noncontact measurement products. The Photon Laser Scanner captures huge volumes of data—an entire room, architectural structure, crime/accident scene—at high speed, well beyond DPI's ½-meter range. DPI's accuracy is even better than our Laser ScanArm, and it can function at a greater distance."
Visitors to Faro's IMTS booth will see a display that includes the FARO-Pratt & Miller Corvette that used Faro technologies to help win four of the top six spots at this year's 24 Hours of Le Mans.
On the laser-imaging side, Faro plans to showcase its Photon Laser Scanner LS, which can scan anything in its 360° path up to 76 m. The system is faster, has 300% less noise for greater clarity, 200% better positional accuracy, and better detection of distant, dark, and oblique objects. For close-range scanning, the new Faro Laser ScanArm V3 is now more accurate, lighter, faster, and scans reflective or dark objects better than in the past. The company will also display its Laser Tracker, which is said to perform measurements to 0.0004" (0.011-mm) accuracy and aligns more quickly and efficiently. The system features a 230' (70-m) working volume, extreme temperature range, and instant laser beam reacquisition capability.
The following products are representative of the equipment that will be shown in the Quality Assurance pavilion at IMTS 2008. — Patrick Waurzyniak
This article was first published in the August 2008 edition of Manufacturing Engineering magazine.