Page 59 - Demo

57ADVANCED MILLING METHODSWhat are the features of a high-performance trochoidal milling cutter? To begin with, the trochoidal milling cutter must be suitable for high-speed machining. This relates to appropriate accuracy parameters, balancing, safety when operated at considerable rotational speeds, and more. Milling with high depths of cut increases the tool%u2019s overhang while the dynamical behavior of a cutter is crucial to ensure machining stability. When milling with a low width of cut, only one tooth engages the workpiece material at any given time. Optimizing a contact area along the tooth is an important factor for stable milling, and the cutter with the most favorable tool cutting edge inclination is a principal part for finding the best solution. The effective evacuation of the thin chips, which are generated when trochoidal milling, does not require a large chip gullet in the cutter.Even a brief examination of the above shows that multi-flute solid carbide endmills (SCEM) or assembled mills carrying replaceable solid carbide heads comply with the requirements in the best way. Indeed, SCEM%u2019s represent most trochoidal milling tools today.Fig. 39. Trochoidal milling is an effective method for improving productivity during the rough machining of geometrically complex surfaces.Accurate Roughing Often, when a part with complex profiles and slots is made from a solid material, the use of trochoidal milling can be quite effective. This technique shapes the part very close to its final form. The remaining small allowance is removed in the next stage: high speed finish milling. In the aerospace industry, the mentioned process is typically used to produce blisks (bladed discs), blings (bladed rings), and impellers (Fig. 39). Therefore, trochoidal milling may be defined by the rather oxymoronic term: %u201caccurate roughing%u201d.