The Angle between the front and the base plane is the Rake angle.
The Angle between the back and the cutting plane is the clearance Angle.
1. Reasonable selection of cutting tool front Angle
The size of the front Angle affects the sharpness and firmness of the blade and determines the cutting performance of the tool.
The plastic deformation of the cutting layer and the friction resistance of the chip flow can be reduced by increasing the cutting tool's front Angle reasonably.
The sharpness of the cutting edge is improved, which can reduce the cutting force, cutting heat and cutting power, improve the milling accuracy and the quality of the processed surface, and thus improve the durability of the cutting tool.
If the front Angle of the cutter is too large, the strength of the edge and the blade will deteriorate the heat dissipation condition, and it is easy to cause the edge breakage.
The tool's front Angle selection can roughly follow the following principles:
(1) the strength of the workpiece material, hardness, the front Angle should be selected a little smaller; On the contrary, a larger front Angle.
(2) can be used for processing plastic materials. A larger front Angle should be selected. When processing brittle materials, a smaller front Angle can be selected.
(3) during rough machining, in order to ensure that the blade has better strength and heat dissipation conditions, the front corner is selected as a small point; When finishing, in order to improve the processing surface quality, let the blade sharp, should choose a larger front Angle.
(4) high-speed steel tool bending strength, impact toughness, can choose a larger front Angle; Carbide tool these two poor, should choose a smaller front Angle.
2. Reasonable selection of tool back Angle
The back Angle of the tool is mainly to reduce the friction between the cutting edge and the back face of the tool and the workpiece surface.
If the back Angle is too large, the strength and heat dissipation of the edge and blade will be weakened, and the durability of the tool will be reduced.
The selection of tool back Angle can follow the following principles.
(1) to process materials with large plasticity or elasticity, take a large back Angle to reduce the friction between the back cutting surfaces;Processing of high strength, high hardness workpiece, in order to ensure the strength of the edge, should take a small back Angle;Finishing cutting force is small, in order to reduce friction, improve the quality of the processed surface, desirable a bit larger after the Angle.
(2) rough machining, cutting force, in order to ensure the strength of the edge, desirable smaller back Angle; Finishing cutting force is small, in order to reduce friction, improve the quality of the processed surface, desirable smaller back Angle.
(3) the rear Angle of the HSS cutter is 2~3 degrees larger than that of the tungsten cutter.
(4) when the radial wear of the dovetail milling cutter will affect the processing accuracy, such as the peripheral tooth wear of the keyway milling cutter, diameter reduction, directly affect the width of the keyway, the back Angle should be appropriately reduced (generally 8 degrees).
(5) the friction behind the cutter teeth and the workpiece in the direction of cutting speed, and the cutting thickness is smaller than the general turning, so wear mainly occurs on the back of the cutter, so the appropriate increase in the back Angle of the milling cutter can reduce wear.