LMT Fette has developed a solid carbide roughing special tool with a fully integrated chip breaker for Airbus' Varel manufacturing plant. Using this tool to machine wrought aluminium alloys on Dörries Scharmann five-axis machining centres not only increases the axial feed rate by 50% (to 13.5mm/rev), but also completely eliminates the disadvantages of pre-existing tool performance instability. . In addition, this new tool reduces the spindle drive power requirement (even at material removal rates up to 3000 cm3/min) and provides a cutting time of 300 minutes (without tool change during this time).
LMT Fette's tool completely solved the problem of forming "nest" chips around the spindle and the tool. This is why Volker Dittmar, Airbus's test production manager, brought in an LMT expert - to process the Typhoon fighter. Gas flanges provide solutions.
The Varel plant in Germany produces complex structural and tooling devices for all seven Airbus plants in Germany. The plant has 1,100 employees and produces more than 2.5 million parts per year, including 19,000 different parts that need to be milled in the factory and more than 4,000 parts for the Airbus A380 large passenger aircraft.
Matthias Maack, LMT's development engineer, described the processing performance of the previously used overall shank type end mills, which could not solve the problem of forming “nest nest†shaped chips, which affected the machining quality of the workpiece and the tool-to-machine power. The requirements are constantly improving. Maack said, "Obviously, we must work with Airbus engineers to develop a solid carbide tool that can use a smooth transition from the arc of the tip to the milling tooth to create an effective chip breaker."
In order to test and optimise tool geometry, tool length, number of teeth and geometry of the chip breaker, in addition to simulations on the CAD system of LMT Fette, cutting tests are regularly performed on Airbus' Dörries Scharmann machines. The tool is optimized based on the material and machine conditions under actual production conditions. Maack added, "This is a bit like F1 racing. Although all the work was done outside the stadium, the drivers also made a crucial contribution to the success of the entire team."
The 25-mm diameter tool developed for aluminum machining was developed at the end and belongs to LMT's Airline series, which incorporates a special chip breaker and spiral inner cooling channel. During processing, the geometry of the chip breaker effectively cuts the chips, and the internal cooling channel directs the emulsion coolant to the cutting area, helping prevent the tool from generating built-up edge. The length of the three helical cutting edges of the tool is 22 mm, and the arc radius of the cutting angle is 4 mm.
When processing the inlet flange of the Typhoon fighter at the Dörries Scharmann ACM-H HPC machining center, the first grooving is carried out with a cutting depth of 25 mm, and then straight processing is carried out at 17 mm/min (coolant pressure is 25-50 bar) Cutting speed is kept at 1492m/min, spindle speed is 19000rev/min, feedrate is 9m/min, axial cutting edge is 13.5mm, and pitch is set to 0.16mm.
Although tool development has been successful, Airbus and LMT engineers are still working hard to further improve and improve their milling performance. At present, they are conducting experiments to analyze the effect of reducing the arc radius of the cutting angle to 2 mm. If this improvement can be realized, the radial depth of cut can be further increased. In addition, by introducing the micro-cutting edge geometry design of the LMT Fette, even superior milling performance can be achieved.