Five essential rules for increasing machining efficiency and extending tool life

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Proper tool selection and optimized machining methods are important for increasing machining efficiency and extending tool life, especially when machining difficult-to-machine materials, such as Aviation Parts.

A high-quality tool for difficult-to-machine materials must have an ultra-fine grain tool base, a sharp cutting angle, a strong cutting edge, and a heat-resistant surface coating. According to the previous application experience of processing difficult-to-machine materials, the reasonable selection of processing methods and parameters is very important for processing such difficult-to-machine materials. The use of special processing techniques is very effective for improving processing efficiency and extending tool life.  

Regardless of the processing methods used, the purpose is to minimize the temperature of the cutting edge and the machined area of the part to be cut, to prevent surface hardening of the machined part and excessive temperature of the tool edge, to increase the heat dissipation area, and to control the cutting force. Methods such as cycloidal path and large feed milling can improve machining efficiency and extend tool life.

First: adequate coolant, proper machining linear speed, effective chip breaking, and reasonable tool relief angle are very effective in controlling cutting edge temperature.

For CNC machines and tools with internal coolant hole(s), the inner cooling function that is most conducive to cooling should be used as much as possible, so that the powerful high-pressure coolant flow takes a lot of cutting heat and ensures that the processing area is kept within a certain temperature range. Even for machining equipment without internal cooling, it is recommended to use an external cooling shank to increase the cooling pressure and improve the cooling effect.

Second: Proper control of the cutting force and cutting speed of the tool is also one of the most effective ways to reduce the temperature of the machining area and extend the life of the tool.

Generally, difficult-to-machine materials are processed using a sharper tool edge, a small depth of cut, and a cutting width. Depending on difficult-to-machine materials, part structure and processing equipment, it is important to choose a reasonable cutting linear speed. In normal processing, the nickel-based alloy should be controlled at 20~50m/min, the titanium alloy should be controlled at 30~110m/min, and the PH stainless steel should be controlled at 50~120m/min.

Third, for the same machine tools and parts, the method of hard-to-machine materials will greatly affect the machining efficiency and tool life of the tool.

Whether it is the cycloidal path machining, helical interpolation and large feed milling, the purpose is to reduce the cutting force and reduce the temperature of the cutting zone. The cycloidal cutting method can minimize the cutting area, minimize the actual cutting angle of the tool, and prolong the heat dissipation time of each tooth of the tool; the helical interpolation makes the cutting amount per tooth relatively uniform, especially at the corner; For cutting mode, the cutting force is effectively reduced with small depth of cut and large feed, so that the minimum cutting heat is generated during machining, and the processing area temperature is the lowest.

Fourth, make sure chip breaks is also an effective way to control temperature rise.

Generally, a large amount of cutting heat is generated on the chips in the metal working, and effective chip breaking causes a large amount of cutting heat generated in the machining to be carried away by the chips. Normally, we don't want long chips in the process. For the processing of difficult-to-machine materials, it should be noted that, especially for the roughing process. In the case of the rigidity of the entire processing system allowed, it should be as much as possible to cause chip breaking during the whole process, and try to use the up-cut method to form the chips. The chips are thinned from thick and have a "9" shape, a "6" shape or a "C" shape.

Fifth, the proper effective tool wrap angle is maintained during machining so that each effective machining tooth of the tool can maximize the maximum cooling time.

Maintaining proper and reasonable tool effective wrap angle during machining is very beneficial to improve the cutting efficiency of hard-to-machine materials and prolong the tool processing life, which is extremely important for processing difficult-to-machine material parts. The effective wrap angle of the tool is reflected in the cutting parameters and has a direct relationship with the cutting depth Ap and the cutting width Ae and the tool diameter Dc. Especially when machining difficult-to-machine materials, full-cut cutting should be avoided as much as possible. In actual machining situation, the tool life is reduced by approximately 30% for each doubling of the tool's cutting angle.

In short, hard-to-machine materials must have high hardness, high strength, high toughness and high wear resistance. For new difficult-to-machine materials with these characteristics, the machining performance is poor, the processing is difficult, the machining efficiency is low, and the tool cost is high. . As a result, difficult-to-machine material parts place higher demands on machined tools.