The expenditure on measuring devices is remarkably high: Both the aligning station and the machine room are equipped with a Renishaw probe and automatic calibration device. This function is important in a turning and machining centre that roughs down, finishes, mills and drills in a single clamping position. There is even a finishing process of exactly 30 µm for very large workpieces, whereby grinding is omitted. "For safety reasons, precision and quality are very important to us", says the expert. "After all, our valves work at high pressures of 20 to 900 bar". "Our customers expect a high level of performance from us in every respect", adds Marketing Manager Chris van Assem. "The requirements have increased in the standards that we need to observe".
Another special feature is the extended retraction and stopping function, which Mokveld ordered for two reasons: Firstly, if there are impending collisions, then the tool is directed out of the machining area and into a safe position. The Siemens 840 D sl control system controls the movement of one or two drive axles during this extended retraction. These drive axles provide various individual retraction distances depending on the situation at hand. Secondly, Mokveld responds with the extended retraction and stopping function in the event of a power failure. The necessary energy comes from the DC bus of the drive system, which is controlled in a way that ensures the energy does not fall below or exceed the voltage limits. Thanks to this clever control, drives do not spin out and can be brought to a standstill.
But what are the aspirations of an experienced production expert who machines challenging valves on a daily basis? Bart van den Bosch: "I hope that one day we will also machine small housings on a machine tool in a complete machining process".