MaxiMill 275 - the face milling cutter for high-alloyed stainless steels

A new milling system optimises rough machining of high-alloyed stainless and refractory steels: our MaxiMill 275. The face milling system, developed for processing flat surfaces on turbocharger housings and exhaust manifolds, is ultra-robust in its construction and is equipped with a maximum number of indexable inserts which cut efficiently and are ground all the way around. This ensures a smooth milling action, high-quality milling results, long tool lives and particularly high efficiency. 

Face milling turbocharger components represents a huge challenge for the milling tools used due to the demanding nature of the material – usually refractory cast steel, often containing niobium. In addition to this, turbo charger housings and exhaust manifolds often only allow for unstable machining conditions. This means the tool needs to be very stable and cut effectively in order to achieve the required quality.

We have set ourselves the task to develop a technically optimised, economical tool system for applications like these. "This has been a complete success with the MaxiMill 275 face milling system," confirms Detlef Erdei, Application Manager Automotive at CERATIZIT. "Firstly, our development team designed the base body to be extremely stable and have low-vibration. Secondly, we were able to optimise the number of cutting edges based on the diameter." Therefore, the largest MaxiMill 275 with 125 mm diameter is equipped with 18 teeth. The smaller 63, 80 and 100 variants have 7, 10 and 14 teeth respectively.

Particular attention was paid to accuracy when designing the insert seat, which keeps the indexable insert firmly and precisely in place using a wedge clamp. This avoids any cutting mismatches and therefore the need for any subsequent height adjustment. This is a plus in terms of user friendliness, too.

The indexable inserts have also been refined. The basis for this is a special cutting material, which is designed for the highest thermomechanical demands. The plates have a positive geometry with a 20-degree rake angle. This enables them to cut effectively and guarantees a smooth tool motion. The fact that they are fully ground around the periphery produces consistent and high precision.

The PVD-coated plates are positioned in the insert seat in such a way that the cutting edge is horizontally aligned with the holder. This way, in contrast to most other face milling systems, which remove chips with the corner chamfer, a significantly smoother surface is produced like with an integrated finishing cutter. The indexable insert can be used on left- and right-hand cutting tools.