Speed up measurement processes, prevent incorrect measurements

The portfolio of the customer from Baden-Württemberg includes quick-connect couplings for low, medium and high-pressure applications. The components are made of brass, stainless steel, steel or plastic, are manufactured in countless variants and are used in aerospace, on the high seas, underwater, in road traffic or in classic manufacturing operations. The couplings are assembled from several individual components and cut to size according to customer requirements. Bores are then required at various points – for example, to make cleaning connections for endoscopes or breathing air technology. These are extremely small holes between three and five millimeters. The tolerances are minimal; each part must fit perfectly. For this reason, the quality technicians always measure the inner contours of the narrow seal recesses as well as their position, width and inner diameter with great precision. In addition to various valve designs – free passage, one-sided and two-sided shut-off, and low-leakage – the manufacturer also offers accessories such as fittings, hoses, or blow-out guns for the couplings.

Solution by chance
Previously, these measurements required a great deal of effort: to determine the inside diameter exactly, employees had to make a cut and then analyze it manually with gages and handheld measuring devices. This took up to 15 minutes per cut. One day, during a sampling session, a supplier mentioned to the quality technician the keyword "contourograph", which would exactly fit the measuring tasks. The latter researched for such a device and found out that one of the most renowned manufacturers of such devices, Mahr in Esslingen, was less than half an hour's drive away from their own company. Mahr was already well known through handheld gages, outside micrometers and other tools that were used on a daily basis. So the quality technician promptly arranged an appointment at the Esslingen technical center, to which the team from the coupling manufacturer took various test pieces.

A measurement effort of only a few seconds
On site, the shortlist quickly fell on the MarSurf CD 140: This conturograph has a measuring range of up to 70 millimeters, which can be extended to 100 millimeters thanks to the extra-long probe arms. The probe arm can be changed without tools thanks to the magnetic probe arm holder, which eliminates the need for recalibration. "Stylus recognition takes place via an integrated chip. It speeds up measurement processes and prevents incorrect measurements," explains Antje Zapfe, Global Account Manager Automotive at Mahr. The company initially decided to rent the device on a trial basis. But just three months later, they were so convinced by the Mahr contour graph that the purchase contract was signed in November 2021 and the device is now permanently used in their own measuring room. Measuring with the MarSurf CD 140 is relatively intuitive, almost self-explanatory, according to the customer, who also praises the teach-in function. The device is also frequently and gladly used by colleagues from the production department. Its great advantage is the great time saving: internal contours can be traced directly and thus cutting and measuring can be carried out in just one step and in a few seconds.

Optimally also determine roughness
The large mounting plate with a 50-millimeter bore and pluggable guide stops also provide a great deal of flexibility in handling. Positioning speeds are up to 200 millimeters per second on the X axis, around 25 times faster than on the model's predecessors. The Z-axis of the MarSurf CD 140 is fully CNC-capable and up to five times faster than usual on the market. "Optionally, the device can be expanded to include roughness value determination from Rz 2 μm," adds Mahr product manager Martin Adler. The smallest probe in the range, with a length of 2.8 mm, is now in continuous use at the customer's site as it perfectly detects the minute bores. In order to further simplify the measuring procedure, the manufacturer of the quick coupling systems plans to invest in additional clamping probes in the near future, into which the parts are simply inserted before the program starts. In this way, the team hopes to save further time in the future, especially for cutting patterns.