Double output thanks to automated electrode production
Krumpholz produces high-precision graphite electrodes on an HSC 105 linear from DMG MORI, these are stored and passed on to the eroding machines by robots when required in unmanned operation.
With more than 60 years of experience in Die & Mold making Karl Krumpholz GmbH & Co. KG is a competent and reliable partner for large car and commercial vehicle manufacturers. The service offering ranges from tool development and design to complete production and colour-matching of the tools and on through to the serial production of plastic parts. The company ensures its productivity and competiveness with continuous process optimisation – which, of course, also includes machining. DMG MORI has implemented a fully automatic interlinked system here, in which an HSC 105 linear machines electrodes that are then moved to a large store by robots and from there to two eroding machines.
“Ensuring our machines operate at full capacity plus reduction of the workforce to a minimum are the key factors for efficient tool making”, says Kay Löffler, Technical Manager at Krumpholz. Needless to say, automation solutions were the obvious answer here. A glance at the mould makers machining concept is a clear indication of this. Back in 2013 DMG MORI installed a DMU 60 eVo linear with a PH 150|8 pallet handling system. Krumpholz produces various small moving parts for the tools on this machine. Kay Löffler explains: “With the aid of the pallet handling system the machine is in operation 24/7. Also where large parts are concerned Krumpholz relies on DMG MORI: the machine park was expanded to include a DMU 210 P in 2014.
The excellent order situation here calls for continuous operation. 95 percent of the tools are destined for the automotive and commercial vehicle sector. Krumpholz also produces serial parts in its own plastics technology facility, e.g. single frames for Audi or complete bumper systems for lorries. Automated production enables the mould makers to take on more orders, as the example of the latest installation shows. DMG MORI connected an HSC 105 linear and two Ingersoll eroding machines via a 6-axis Kuka robot. A store with space for 400 electrodes – ranging in size from 50 x 50 mm to 1,300 x 150 mm – is also integrated. The eroding machines are supplied flexibly from this store in dependence on the order situation.
“The HSC spindle with speeds of up to 40,000 rpm and linear drives with rapid traverses of 90 m/min enable accurate and at the same time dynamic machining” is how Kay Löffler assesses the performance of the machine. High-speed milling is therefore an unbeatable method for graphite machining – from both a qualitative point of view and where efficiency is concerned. However, efficient production of electrodes on the HSC 105 linear is only one element that leads to the high output of the system. The Technical Manager explains: “The large store also means that the eroding machines can work in continuous operation. This process was formerly carried out on separate machines. “We now produce double the number of parts on the automated system with the same workforce.”
Automation ensures a competitive edge
The workers are now mainly responsible for the preparation of the electrodes. These are mounted on their holders and the key information for the electrodes are written on the RFID chip using a barcode scanner – from CAM through to the finished electrode including outputting of the NC programme for the eroding machines. The workers have meanwhile been redeployed to a different area, reports Cristopher Zwosta, Production Planning, and Tino Schnapp, CAM Manager: “The large store and high output mean the automation system requires continuous replenishment. That is why we have expanded the CAM department in the meantime.”
Kay Löffler sees the automation from DMG MORI as a good example for the direction of the future development of the tool making: “If we want to retain our competitive edge, we will have to forge ahead with similar manufacturing solutions in the coming years.”
