Research And Application On High-speed Hard And Dry Cutting With PCBN Tool

The Polycrystalline Cubic Boron Nitride(PCBN, for short) was developed in the middle of the 1960's.This material has many advantages such as high hardness, good wear resistance, thermal and chemical stability, low fraction factor, high adhesive resistance, high quality of machined workpiece surface and so on. The PCBN tool is excellent in machining Iron family metal used in hard cutting.It applied in cutting hardened material instead of grinding gradually and broadly.In the 1st and 2nd chapter the fascinating history of tool material are reviewed .Then the concept, mechanism and applies of hard cutting are summarized. The types, sintering techniques and its grinding of the tools are discussed, for the sake of right choosing and using of the tool. The part in the dissertation is stated also for analyzing the tool wear and tear.In chapter 3, the cutting speed and workpiece temperature, cutting chip and tool wear are being researched and discussed in different cutting speeds when cutting alloy-steel 42CrMo.After the workpiece temperature measured by ThermaVision, it is proved that the workpiece temperature was not high and changed little. Through the SEM and EDS analyses for chip and tool wear, it is proved that PCBN tool is suitable for High-speed Hard and Dry Cutting. It is suitable for PCBN tool to cut hardened alloy-steel 42CrMo instead of grinding.In chapter 4, the wear and tear of the tool is discussed when applied on High-speed Hard and Dry Cutting quenched stee.In chapter 5, for the requirements of powder metallurgy valve seat insert machining in ATP Corporation, We chose and grind the PCBN tool. The tools are well used in manufacturing: the single tool point can machine about lOthousand workpieces, added with regrinding it can save a lot of money for ATP. The tool life is about 4-5 times than the tool used in the company before.The author also analyzes the wear and tear of the tool: the main kinds of wear are chemical wear and diffusion wear, and mechanical wear and adhesive wear are always indwelled in the cutting process. When the blade collapsed, it is the time to change a new one. The availability measure in right using of the tool is listed too.