Stamp of approval: the Swiss are known for their precision, so a shop located on Lake Constance in the German, Austrian, and Swiss area had to guarantee the measurements of its stamped productions to maintain the tradition of accuracy.
Krayer GmbH specializes in the production of 3D formed and stamped parts. Located on Lake Constance near the Alpine rim of Germany, Austria, and Switzerland, the company dates back to 1884. That was the year Franz-Joseph Krayer founded a fabrication shop in the lakeside town of Langenargen. The business weathered two world wars only to see its stamping equipment confiscated by allied occupying forces at the end of WWII. However, the company bounced back and expanded, making up its losses.
More than 1,000 tons of rolled and cut sheet metal in all grades, shapes, and thicknesses are kept in company stock; it stores tens of thousands of tools, using a motorized storage system for quick access. Krayer's customers are primarily subcontractors to the commercial vehicle sector. Krayer also produces a plethora of stamped sheet metal parts varying from large sinks for the restaurant industry to indestructible keyboards found at public Internet booths.
"We specialize in fabricating small and medium-sized runs of stamped and perforated sheet metal parts," Christoph Brugger, managing director, said, "with series running anywhere from just one part to tens, hundreds, or thousands of parts.
"For smaller runs, we rely on old-fashioned manpower. Larger runs are automated, and we use industrial robots to free our workforce for tasks where programming would be too time-intensive for a robot. Our collection of tools lets us alter production runs. We can manufacture new tools rapidly, which is very important for the development of prototypes. Within a short time, we're able to produce sample parts based on test tools, letting us keep pace with the needs of our customers."
Changing times and a global economy pushed Krayer toward its ISO 9001 Certification to ensure a worldwide reach for its products. Depending on the specifics of a production run, representative samples need to be compared against part drawings. Checking the dimensions of the parts produced can slow the production, as parts need to be taken into the metrology lab where their dimensions are compared to specifications.
The inspection process is troublesome if parts are large, heavy, or difficult to handle. This issue led to a search for a more efficient means of measurement.
After viewing a Romer Omega articulated arm from Romer Inc., Wixom, MI, at a trade show, Krayer management arranged for an in-house demonstration of the mobility and flexibility of the CMM. A year later, Krayer depends on the CMM to streamline and expedite its metrology tasks as a part of its ISO 9001 compliance.
Another driver for acquiring the arm was Krayer's need to have an alternative to a form tester. With the arm, Krayer can check the contours of the smallest parts, something not possible with a classic form tester.
The 7-axis articulated arm operates much like a human arm, and is available in measuring ranges of 6', 9', 10', and 12'. The counterbalance works from any position in the arm's reach, above and below the midline.
Romer incorporates a Zero-G counterbalance that offsets the weight of the arm and probe allowing one-handed operation. The articulated arm is made of carbon fiber and aluminum, so it is a lightweight shop floor inspection device weighing less than 20 lb.
The CMM provides both high-precision probing and optional scanning capabilities.
To Infinity, and Beyond
The arm's patented infinite rotation of principal axes makes the inspection of hard-to-reach areas possible. The CMM's moving elbows and wrists make it is easy to setup a part and walk around it, and move around fixturing too. For most parts, within one or two setups, all points can be reached--including under the part--and studied. As an operator gathers points from a part's surface, the data can be visualized and verified as under- or over-tolerance. Once a session is completed, a report can be generated in formats such as spreadsheets, PDF, or RTF files for further analysis.
"The benefit of the articulated arm is its portability," Brugger said. "We've mounted it on a mobile work station, so we can take it to any machine. While one worker is producing parts, a metrology technician can perform measurements on the spot. It's faster than the conventional measurement methods, letting us perform measurements in a fraction of the time once required."
"The arm is easy to use, and the workflow is quickly learned by any employee," Michael Banhardt, production manager, said. "The production process isn't interrupted. The machine operator doesn't need to leave his station to take the part to the stationary CMM and compare the part's dimension to the technical drawings. The evaluation is done in the PC-DMIS software, and we have documented results for the customer."
PC-DMIS, from Hexagon Metrology, North Kingstown, RI, is an inspection software package that works with the Romer arm to collect, evaluate, manage, and present manufacturing data. The software lets manufacturers capture dimensional data from the surface of parts, analyze it, and use the results to reduce scrap, improve throughput, and lower production costs.
Any Which Way
A feature of the software is its Any-Order Measure that lets the operator probe parts in the order that's the most convenient and efficient without having to follow the steps of an inspection routine. The software tracks what is measured and only evaluates dimensions when all of the necessary information is available. PC-DMIS Portable aligns complex parts, and has a functional range for best fit and iterative alignments of data. During probing, the software automatically switches between using the probe tip and shank measurement as necessary.
Krayer stays true to its roots as a closely-knit family of long-time associates. It has about 50 employees. Over the years, the company has been able to expand its business to include German and greater EU marketplaces, as well as customers from the Far East. Romer