Knowledge

Trochoidal milling - applications, advantages and tool selection

For most manufacturing companies nowadays, process optimisation with regard to shorter machining times and an extended tool life for the metal cutting tools are the keys to greater efficiency. Intelligent milling strategies, such as the trochoidal machining process, are the solution: in conjunction with our new CircularLine CCR end mills, tool service lives can be extended and components produced even faster. 

What is meant by trochoidal milling?

New CAM programming systems and control cycles are used for trochoidal milling. These enable consistent tool clinching and a consistent average chip thickness. An optimum and effective machining process is therefore ensured. This type of machining strategy is particularly suited to the machining of deep slots or high flanks.

Trochoidal milling of deep slots and high flanks

The benefits of trochoidal milling are noticeable when machining high volumes, deep slots or high flanks. In addition to extremely high process security and considerable time savings, an increased tool life can be achieved, along with reduced tool wear. This is because the angle of engagement remains as small as possible during trochoidal milling, reducing the vibrations generated. The fact that the end mill has more time to cool down during the process also reduces the amount of wear.

Raw material input during trochoidal milling

Another particularly attractive aspect is the raw material utilisation of the carbide. Although the amount of carbide powder required to produce the tool is somewhat greater, the cutting length of the tool is twice as long. Wear in relation to the volume being machined is therefore distributed across the entire length of the longer cutting edge. If this is compared again with the raw material input, the result is extremely positive and cost-effective.

Tool selection for trochoidal milling

Due to the higher radial forces, greater demand is placed on the tool, which requires a special, more stable core geometry. Furthermore, both the carbide and coating must have high thermal shock resistance, as the temperatures generated at the cutting edge fluctuate strongly due to the engagement and cooling intervals. If the wrong tool is selected, microcracks may form on the cutting edge or edge breakage may occur.

 

The new CircularLine CCR end mills possess all these properties and are the first choice for optimum results with the trochoidal milling process. As demonstrated in particular by the application of the legendary "DRAGONSKIN" coating, maximum emphasis has been placed on ensuring that the end mills exhibit a high degree of resistance. Like all high-performance tools that have a "Dragonskin", the new CCR end mills are extremely robust and wear-resistant and can withstand strong temperature fluctuations.

Special chip breaker ensures optimum chip removal

Another special feature of the cutters: They have a special chip breaker which has been ground into the cutting edge geometry. The need for this becomes apparent when considering that chips produced by a cutting length of 4xD and a diameter of 12 mm without a chip breaker, for example, would be 48 mm long. The chip breaker restricts the chip length to 2xD and optimum chip removal is ensured, even for problematic materials.

Two versions: universal application and machining of aluminium

Two versions of the CircularLine end mills are available: one for universal applications and another specifically for the machining of aluminium. While the six flutes of the CCR-UNI ensure quiet running and a high material removal rate, the four flutes of the CCR-AL ensure a large width of cut. They are available in 3xD (steel) and up to 4xD (aluminium) and can reach cutting depths that correspond to the entire length of the cutting edge.

The CircularLine subjected to a hardness test: excellent results for the machining of stainless steel (Duplex-VA)

As tests have shown, it is possible to use significantly higher cutting parameters when using trochoidal milling with CCR end mills than with conventional machining processes, shortening machining times considerably. Even applications that were previously considered to be very difficult could be dramatically improved. In the past, problems were always encountered with chip evacuation for materials such as stainless steel 1.4404. Unusually for this material, it was completely dry machined during the tests, leading to the discovery that the thermal shock effect could be minimised. As a result, a considerably longer tool life is possible compared with wet machining. In one case, the conventional machining time for the workpiece was reduced from 12 minutes to 5 ½ minutes and the general tool life was tripled. These figures clearly show what combining the optimum tool with the right machining strategy can achieve. 

Trochoidal milling now also possible in turning operations

The tried-and-tested milling strategy can now also be applied to turning operations. Read more here: Trochoidal turning using CAM systems.