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Trochoidal Challenges on Difficult Materials Solved By LMT
Trochoidal Challenges on Difficult Materials Solved By LMT

Trochoidal Challenges on Difficult Materials Solved By LMT

Added to MTDCNC by LMT UK Ltd on 27 October 2016

In numerous applications such as engines in aircrafts, exhaust gas turbines in cars or knee joints in medical technology all use materials that are difficult to process using conventional milling methods. In this case, trochoidal milling is the ideal solution. Users can significantly reduce processing times with high quality and process reliability. A machining workshop held by LMT Tools and Coscom has shown the tools that are suitable for trochoidal processing and what role machine tools play in the equation.

 The foundations for trochoidal milling with the circular feed motion were laid decades ago. But it is only through the combination of high-performance tools and machines with the appropriate CAM software that users can benefit from the complete performance potential of this procedure. This particularly applies to materials that are challenging for conventional slot and edge milling tools. Stainless steels tend to be adhesive and very tough whereas Nickel-base alloys show a high machining energy and resilience. In the case of hardened tool steels, the extremely high mechanical strength leads to fast wear and tear of conventional cutters. All these materials are widely used in the automotive and aerospace sectors.

With difficult-to-machine materials, users can optimally benefit from trochoidal milling. In a joint machining workshop held in early 2016 in Schwarzenbek, LMT Tools and CAD/CAM specialist Coscom showed how this can be done. Clemens Mohr, Head of Training Center LMT Tools, summarised the technical requirements: “First of all, customers require a CAM programming system with a software module for trochoidal milling. The machine tool should have fast controls and high travelling speeds. Generally, the machine should be equipped with an internal coolant supply. The geometry of the workpieces must also be suitable for processing. Everything else is a question of the right tool.”

Tools for special challenges

In a live demonstration, Clemens Mohr presented the suitable tool solutions. The DHC (Different Helix Cutter) end mills by LMT Fette were at the centre of attention. These solid carbide end mills are suited to trochoidal processing of tempered steels and stainless steels. Due to the different angles of twist, users can achieve high cutting depths and high feed performances at optimum running smoothness. The DHC Hardline end mill is the first choice when it comes to trochoidal milling of particularly hard materials. Its resistant cutting material allows processing of high-strength materials up to 1600N/mm² or hardened tool steels from 45 to 60 HRC. In the case of super-alloys like nickel or titanium, the DHC INOX end mill has proven proficient. Its cutting material and nano-crystalline PVD coating ensure maximum performance and low wear and tear, even at extreme cutting values.

Putting Tools to the Test..

An internal experiment carried out by LMT Tools and Coscom demonstrated the possibilities of trochoidal milling. For this purpose, a workpiece made of high-strength cold work steel of 60HRC was processed using an end mill of the DHC HARDLINE series (material 1.2379/X155CrVMo12-1). The experts first tried to mill the slots in the workpiece conventionally at a cutting speed of VC = 80 m/min and a cutting depth of AP = 4 mm. However, the cold work steel could not be successfully machined because the cutting edge was destroyed by the excessive heat after only a short time. As an alternative, a trochoidal milling movement was programmed into the CAM system. This proved to be highly successful. The DHC Hardline reached a cutting speed of up to Vc = 180 m/min at a cutting depth of ap = 16 mm.

“Examples such as this internal experiment show that trochoidal milling opens up new paths for processing difficult materials,” said Mohr. “For this purpose, we closely cooperate with CAM partners such as Coscom. This way, we are able to offer our customers a complete solution for their milling strategy – including suitable tools and a perfectly tailored programming system.”

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