Several aspects affecting the performance of tungsten carbide drilling bit - Editor By WTFTOOL
(1) When graphite is machined with negative rake angle, tool edge strength is better, impact resistance and friction resistance are better. As the absolute value of negative rake angle decreases, the wear area of flank changes little, but the overall trend is decreasing. When positive rake angle is machined, with the increase of rake angle, the strength of tool edge is weakened and the wear of flank is aggravated. When the negative rake angle is machined, the cutting resistance is large and the cutting vibration is deleted. When the large positive rake angle is machined, the tool wear is serious and the cutting vibration is large.
(2) Back angle, assuming that the back angle is increased, the cutting edge strength decreases and the wear area of the flank is gradually increased. When the tool's back angle is too large, the cutting vibration is strengthened.
(3) When the helix angle is small, the cutting edge length of all cutting edges which cut into graphite workpiece at the same time is the longest, the cutting resistance is the largest, and the cutting impact force is the largest, so the tool wear, milling force and cutting vibration are the largest. When the helix angle is larger, the direction of milling opening force deviates from the general situation of the workpiece to a large extent, and the cutting impact caused by the breakdown of graphite material increases, so the tool wear, milling force and cutting vibration are also increased.
Tool material is the basic factor to determine the cutting performance of the tool, which has a great influence on the processing compliance, quality, cost and tool durability. The harder the tool material is, the better the wear resistance, the higher the hardness, the lower the impact toughness and the more brittle the material is. Hardness and toughness are a pair of contradictions, which should be overcome by tool materials. For tungsten carbide cutting tools, the common TiAlN coating can choose the materials with relatively better toughness, that is, the cobalt dew is slightly higher; for diamond coated graphite cutting tools, the hardness is relatively better, that is, the cobalt dew is slightly lower;
