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WFL: With innovative spirit to the top

Photo by WFL Millturn Technologies GmbH & Co.KG

Gewerbepark Holzhausen” is written on a signpost between fields and a small municipal road. Nothing here suggests the high-tech potential that awaits us in this small town near Linz airport. Founded in 2007 by Dieter Grebner, Peak Technology supplies the Formula 1 industry and various aerospace companies with complex and ultra-light carbon fiber composite structures.

Future topics such as the electrification of aviation and autonomous flying are omnipresent here. Peak’s 120 employees manufacture components for aircraft of the future. Matthias Lechner, Technical Director, explains the visionary projects. Peak Technology is already working on what the mobility of the skies will look like in 10 or 20 years. But Peak is going much further than that: For space projects, the company produces high-pressure accumulators wrapped in carbon fiber, igniter housings and structural components. The ultra-light high-pressure accumulators, which can withstand a pressure of up to 700 bar, are already almost part of the standard repertoire. The components for the engine periphery of the Formula 1 racing cars, which are also part of Peak’s portfolio, almost sound like a few parts of a steam engine in all the science fiction projects. Regardless of the high-tech requirements, the company sees itself as a manufactory, as many processes in fibre composite technology are carried out by hand in elaborate manual work. So traditional craftsmanship combined with high-tech manufacturing. In CNC manufacturing, Peak Technology has been using an M35-G MILLTURN from WFL since 2019.

To meet future requirements

The desire for improvements in CNC manufacturing has been taken into account in the last three years. With the purchase of an M35-G MILLTURN, the state-of-the-art machinery was recently completed to meet future requirements. In the past, the parts were machined separately on lathes and milling machines. “We wanted to reduce retooling to an absolute minimum and simplify production planning. In addition, the tolerance requirements of the customers are very high and can practically only be achieved by complete machining and as few setups as possible”, Matthias Lechner, Technical Director of Peak, summarizes the requirements. After all, free-form surfaces with tolerances in the range of 0.005mm must be adhered to reliably in the process. Air conditioning of the entire production as well as measuring technology at the highest level are basic requirements for these demands. The lot sizes of the individual orders range between 10 and 30 parts. “But even with “series” of 10 pieces, only one part is ever manufactured and then another one a week later, because our customers do not want the whole delivery at once, but everything “just-in-time”, explains Lechner. “We are currently producing 10 to 15 different parts on the WFL MILLTURN. But there are more practically every day. The materials to be machined are metallic materials such as titanium, high-strength steels and aluminum, as well as carbon fiber components,” explains Christian Brunner, team leader of the machining production. “If we had a MILLTURN now, it would be sooo much easier,” he is said to have said earlier for difficult components.

In the course of the company’s expansion, the time was 2018. “We looked at all the market competitors in the various plants. What we particularly liked about WFL’s MILLTURN was the inclined bed design with the solid cast bed. So a very rigid machine. Finally, the proximity to the manufacturer was also important to us. Many international companies work through dealers. That would have been out of the question for us,” Matthias Lechner recalls.

A higher milling spindle speed

“As we often work with very small tools, the milling spindle speed of 16,000 rpm was very important. The standard option of 12,000 rpm was not sufficient. It’s a good thing that WFL had already had a gear spindle variant with 16,000 rpm in test operation for some time and had also been running successfully for a customer. Chip volume and performance are actually not our main focus. Rather, we need the speed in combination with high stability and precision,” agree Brunner and Lechner. Tiny ball cutters are used especially for components with very small radii. The parts are clamped in a 3-jaw chuck with quick-change jaws, whereby a Hainbuch clamping system accommodated in the chuck is currently used for testing. In some cases, the workpieces are also clamped from the inside using a clamping mandrel. The clamping pressures are freely programmable when the workpieces are clamped in the chuck and can be changed in small steps under NC control within one clamping operation. The program-controlled change of the clamping force is also possible without opening the chuck. These requirements are necessary for the thin-walled workpieces. “We learn something new every day and although we are well positioned in 5-axis milling, MILLTURN always shows us new possibilities that we have to approach little by little. This is simply another dimension of complexity. 5-axis milling is constantly in use at MILLTURN. This works perfectly and delivers accurate results. We are highly satisfied with it. In addition to turning, drilling and milling, in the future, gear cutting will also be performed on the MILLTURN,” says the technical manager, summarizing his experience with the new machine.

The software challenge

There was one software-related nut to crack for WFL in the run-up: By means of Form-Inspect from M&H, the adjustment between the zero point in the CAM system and the actual position in the machine should be carried out automatically. The clamped raw part is measured in space by means of measuring probes. With this information, the zero point of the machining can be corrected to the actual position of the raw part directly on the control using a special software solution. If, for example, the position or shape of the raw part does not correspond exactly to the CAD, the ideal position is determined by means of a best-fit calculation, the coordinate system of the CNC program is shifted or rotated to the ideal position and a constant allowance is ensured on the entire raw part. This ensures that the allowances and continuous cutting conditions are as constant as possible throughout the machining process. The system was adapted in close cooperation between WFL and M&H and tested extensively at WFL. Immediately after delivery of the machine, the system was fully functional.

For more information, please visit: https://www.wfl.at