In today’s competitive automotive world, quality is no longer an option—especially in fit and finish. There is an oft-quoted phrase in business that you get what you measure, and dimensional validation using various metrology systems is how engineers deliver high-quality fit and finish.
Up until now, the most common way to conduct a full dimensional scan of automotive body parts and assemblies meant selecting a few parts to move to an off-line or near-line measuring system in a stand-alone cell. Collecting metrology data and crunching the numbers to understand if parts were in or out of tolerancing was too time-consuming for an in-line system. This meant delayed information and corrective actions.
An in-line system that captures comprehensive dimensional metrology data is something the industry has been striving for. There is a growing customer need for such a system, according to Cliff Bliss, WLS National Sales Manager for Hexagon Metrology. “With advances in computers and related solid state systems, we are able to deliver measuring systems directly inline,” he explained, able to keep up with typical automotive peak rates of 60 jobs-per-hour.
Two for one
Coupled with speed, the other key aspect that Bliss stressed is that the system delivers quality control data in addition to process control data. Process control data—think statistical process control—is accurate enough to understand if the manufacturing or assembly process is trending out of bounds. This could signal the need for corrective action, “but then engineers would need to take parts into an off-line CMM room and make detailed measurements to understand what is happening,” he said. The 360° SIMS will provide both trend data and measurements with enough absolute accuracy to perform that second, detailed step right on the shop floor.
Since the platform is the core of the system, the system is not constrained in the number of robots, transfer systems, or measuring devices. “We expect the WLS white light to be the primary sensor because of its combination of precision, speed, and insensitivity to vibration,” said Bliss. “But we also offer fixed measurement systems, such as lasers and 2-D cameras. For example, a 2-D camera would be good for measuring studs where the white light system is not as effective.”
Hexagon Metrology is a company that has grown both organically and from acquisitions. The result is a company with wide-ranging expertise in sometimes diverse fields of metrology. “We developed a brand new computing platform for the 360° SIMS,” said Bliss, combining computing elements from existing CoreView software, elements from the newly acquired Spatial Analyzer from NRK, PC-DMIS, along with brand new elements. The result is this new family of measurement solution that engineers can integrate into automotive production lines. Manufacturers can gather data during launch, ramp-up, and ongoing production. They enable full-surface inspection and critical features measurement of up to 100% of car bodies, parts, and subassemblies.
While each system will undoubtedly require a certain amount of customization, the company is focusing on providing systems that specialize in body-in-white, chassis, closures, and powertrain measurement applications, according to Bliss. The 360° SIMS is compatible with commonly used industrial robots, PLCs, automation devices, and safety equipment, according to the company. Cell configurations could be inline, near-the-line, and offline to support a variety of customer applications throughout stamping, body shop and final assembly sub-plants. In keeping with a shop floor philosophy, the system is driven by a simple touchscreen interface. Operators with basic training can supervise the measurement process, easily visualize results and identify root cause for quality concerns, according to Hexagon.
While accuracy is dependent on the production application, Bliss said that tests performed by Hexagon confirm that it will measure a BIW of overall accuracy of 250 µ to 2 sigma and static accuracies down to about 50 µ to 2 sigma.