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Schwer und Kopka GmbH - effiziente Prozess- und  Werkzeugüberwachung Ihrer Produktionsmaschinen

"We need high output from our rotary thread rollers in order to be able to offer competitively priced products in the range of M1.6 to M6” explains Diedrich Klute who is the responsible manufacturing manager at Tweer & Lösenbeck. "We would have loved to run our rollers during unmanned shifts after the regular production period ends, which would reduce our costs even further. Unfortunately, a reliable monitoring solution for our high speed rollers was not available until recently. We had to sacrifice the idea of running unattended in favor of the quality aspects".

Improving quality and productivity at the same time

It came as a logical step to sit down with the experts of Schwer + Kopka (SK) to try to find a reliable and practical solution for this problem. "We have been using the SK load monitors for many years on all of our cold heading machines and know what we can achieve. Hence, we wanted to transfer the good results into the thread rolling department as well" describes Diedrich Klute regarding his motivations to expand the use of monitoring.

"The difficulty in monitoring the planetary rolling process in the past has been that typically, several parts are being rolled in between the dies at the same time. This has caused problems for conventional process monitoring systems when it came to detecting the different force readings for each rolled screw," summarizes the manufacturing manager. In addition, the traditional sensor concepts were not suited to deliver consistently strong sensor signals when rolling smaller diameter parts. The force signals were too weak and did not provide a good representation of the actual rolling process. "It took us a number of different approaches working with the technicians of Schwer + Kopka, but we have now developed a new sensor concept which works very reliably, and it is very easy to retrofit to all our existing machines" says Diedrich Klute. "The new SK system has been tested extensively over a period of several months. The measured roll force signals are stable and repetitive allowing us to run the monitor with very tight envelope limits. Quality is further supported using our specially designed sorting gates which are connected to the SK 400 load monitors. Whenever the monitor detects a “suspicious” force signal, the gate is activated to separate the defective part/s. Since the monitor has been installed on this machine, we have not found any undetected bad parts, nor have we had a single customer complaint.”

Expansion to all planetary rollers is in progress

The excellent results achieved with the initial test system have led to the installation of eight (8) more SK 400 load monitors on other planetary rollers. The machine operators also value the new monitoring technique and the simplicity of operation. Shortly, all planetary rollers at Tweer & Lösenbeck will be equipped with SK load monitors.