On-Machine Measurement Ensures Quality Production

On-Machine Measurement Ensures Quality Production

Contract manufacturer Helmut Christmann GmbH has earned its reputation as a premier manufacturer of high-precision parts by employing a variety of different production techniques and carefully monitoring parts with sophisticated on-machine measurement technology. In order to achieve the necessary precision and assure process safety in production, the company relies on machine-integrated production measurement technology from Blum-Novotest (Erlanger, KY).

With a workforce of 40 people, Helmut Christmann GmbH, based in Birkenfeld near Pforzheim in the Baden region of southwest Germany, manufactures high-precision, often extremely small, fine mechanical components. Its customers are found in a wide variety of manufacturing sectors, from medical technology to electronics. Lot sizes can vary from one to 20,000 parts per year.

The company was founded shortly after WWII by the grandfather of the present-day CEO, Marcus Christmann. The company initially made watch cases and components for watch and jewelry manufacturers. Historically, Pforzheim is renowned for its goldsmith trade. In the 1980s, Christmann became a contract manufacturer, which entailed a move into toolmaking and specialization in machining complex, high-precision, progressive composite dies.

“We specialize in high-precision parts involving a number of different production techniques. We turn parts that are just 0.2 mm in diameter, and carry out electrical discharge machining [EDM] on wire that is just 0.03-mm thick,” said Marcus Christmann.

“We mass-produce carbide metal with a contour accuracy of ±0.002 mm. To assure such levels of precision, we employ workpiece and tool measuring technology on our machining centers,” said Christmann. Whereas many other contract manufacturers specialize in one production technique, Christmann operates a large portfolio of machinery covering a wide range of different processes from milling and turning to EDM and grinding.

The company has acquired advanced levels of know-how in the production of high-precision parts over a number of years as well as in the measuring technology that is so important to production of quality precision parts. Today, in-machine measurement is a common practice in milling processes. Probes are mounted on toolholders and fitted into the spindle as required. The machine then scans the desired measuring points. The measurement signals are relayed to the machine optically or wirelessly, depending on the design variant and model chosen.

The result is that complex measuring tasks can be automatically integrated into machining programs without the need to unclamp the workpiece, transport it to the measuring room, and clamp it back on. Eliminating the need to remove the workpiece is especially important in the production of high-precision parts, as it is practically impossible to clamp a workpiece twice in an absolutely identical way. In-machine measurement also saves a great deal of time, as well as reducing scrap rates.

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