"We place extreme demands on our suppliers“

Turning, drilling and milling in only one clamping: That is the main feature of the DBF 630 machining center. Added are accuracies of 5 to 6 μm – all features pose extreme demands not only on the machine tool manufacturer but also on suppliers. Moreover the top-quality machines are to be mounted at a reasonable time and cost. Preassembled energy supply systems come into operation here. They provide the edge to cut down the cost of the process.

"We are a special machine manufacturer and make technically top-quality machines. No machining center equals another," clarifies the authorized representative Stefan Nethövel, Divisional Director Materials Management/ Logistics of the Dörries Scharmann Technologie GmbH, from the start. "And our main focus is on the transparent costs of the process. We are always in search of potentials for saving. In our view, they lie, for example, in the development and storage costs as well as in the installation time. The constructive collaboration with our suppliers therefore plays a completely significant role", says Stefan Nethövel. "They must respond fast and flexibly to our very high and fast-changing technological requirements!"

For the past many years, DST uses energy chains manufactured by igus® GmbH, Cologne. To get a firmer grip on the costs, you look around for more potentials for saving. Started about two years ago with a multifunctional portal machining center, two preassembled energy chains are now used for the new machining center DBF 630. They are marketed by igus® under the name ReadyChain®. "The goal is to make available, on demand, ready assembled energy supply systems on site within two weeks“, says Stefan Nethövel.

"In a market analysis we have determined that a high demand exists for the small parts machining, among others, in the automotive sector. The demands on both the accuracies and the unit costs have risen further, so that we have developed a machine which meets these customer requirements," reviews Stefan Nethövel. Complete machining of pump and valve housings, fittings, gaskets and rock bits with radial and axial runout accuracies of 5 to 6 μm are among the typical applications of the new machining center. Its guarantee of success is the turning, drilling and milling head (DBF). To turn on the fixed workpiece, the rotating tool must radially move +/- 35 mm (servo axis). The compensation masses integrated in the head automatically make up for the otherwise acting imbalance. Thus speeds of up to 1,200 min-1 are possible for the turning operation. For drilling and milling, a 35 kW spindle accelerates up to 3,500 min-1. The compact machining center with 630 x 630 mm pallets and load capacities up to 600 kg has a chain magazine with a capacity of up to 60 tool pockets. Alternatively a rack magazine with 150 to 330 pockets can be opted.

"We have shown that with this machine the performance of the customers can be raised by around 30% due to the fast machining time", explains Stefan Nethövel. The machining center can, if need be, stand in line. A concept has already been developed for a fittings manufacturer, which provides a linkage of up to five machines in the finishing stage.

"Very high demands are placed on the availability of the machining center in operation. Generally it runs round the clock in the manufacturing plant. All the components used should be accordingly durable", says Stefan Nethövel. "Our top quality machines call for quality products. “That reflects also in the choice of the igus components. From the actual energy supply system to every Chainflex special cable, all bus, servo or control cables are equipped with integrated strain relief elements. Added to it are additional shelving elements to raise the service life of the individual cables. Plugs, connectors and encased steelwork provided by the customer round off the completely preassembled system.

"Our endeavor was to install a complete system, which is delivered ready to mount prior to the given deadline. From the beginning, we developed a concept together with igus to connect the energy supply system with the machine in such a way that on one hand there are less interfaces and on the other, a clean supply of all components is guaranteed“, clarifies Stefan Nethövel. "The cost factor also adds to it of course. Separate assembling costs a lot of time and money. It's not only the storage costs which accrue but also the purchase costs. Every single part must be taken in hand several times that the expensive installation times simply didn't pay off for us. Our core competence is the special mechanical engineering and not the mounting and subsequent assembly of the individual components. “

An energy supply concept emerged in recent months through a close collaboration of the two companies. It is the task of our design engineering together with the suppliers to develop a functioning solution, so that no problems occur during the installation of the machining centers. As we manufacture exclusively for customer requirements, it proves difficult to accurately define the respective lengths of the feeder lines. Here we require a supplier who can supply technical support, respond flexibly to the various requirements and above all, can implement our order in a very short time, clarifies Stefan Nethövel. If the machine concept is accepted, the delivery of a complete preassembled energy supply system should be basically guaranteed within 10 working days.

Michael Offner, the igus® product manager for energy chain systems, is able to meet these demands. "In the head office in Cologne, not only the assembly stations have increased by 30%, but great focus is laid on the storage. There are over 6,000 connectors and components in our stock for all well-established drive system manufacturers. So, we can respond fast not only to the requirements of the machine tool manufacturer. “

"We developed and built the DBF 630 machining center within around seven months. We appointed the individual suppliers quite early on. And igus® was there from the start. In my view, there are so many arguments in favor of preassembled energy supply systems. However the expenditure for the construction should be manageable," reports Stefan Nethövel.

At DST, in the choice of suppliers, great value is placed on quality and good partnership. As they were involved in the development of the machine, they could prove their capability right from the construction of the DBF 630's prototype. "With the machining center, we demonstrate to our customers our capability and offer them high process reliability and future security. Our suppliers should be able to follow this technical demand, also to adapt the separate processes to the constantly changing requirements any time. We have not only initiated some developments but also expect that we can participate any time in the technical know-how of our system partner. In the collaboration with igus, we have acquired good experience regarding this in the development of the machining center," Stefan Nethövel concludes by looking back on the cooperation.