The Rearch Of Optimize Technolog And Cuttery When Cutting Graphite In High Speed

Graphite has higher temperature strength,low thermal expansion coefficient,good process ability,well electrical and thermal conductivity.Graphite was widely used in metallurgy,electric furnace,electrical discharge machine,etc.Although the graphite is a kind of free cutting material,but for EDM graphite materials must have sufficient strength in order to avoid the damage in the process of processing and using.And the shape of electrode and so on put forward higher request to grain size and strength of graphite electrode.This leads to the collapse broken graphite workpiece in machining process and tools easy to wear and tear.Therefore,how to prevent the workpiece avalanche crushed,to improve its surface quality and to reduce the tooling cost became the important obstacle for graphite electrode processing.In this paper,the performance of tools are optimized through the angle of cutting tool,cutting parameters and the way of cutting process,etc to decline cutting impact force,cutter wear the roughness of workpiece after machined and increase the cutting efficiency and quality.The full text included three aspects of orthogonal cutting,milling and drilling.Mechanization of graphite?optimize of process and coat and angle of cutter are been researched in the paper.The details are below.On orthogonal cutting:Orthogonal cutting is one of the most ideal,the simplest way of cutting.To test the cutting performance difference of tools with different angles and graphite materials in order to prepare for optimize the tools'angle and process parameters.At the same time,record the formation process of scraps by using the high speed camera.And analyze the character of cutting force when cutting graphite by different tools and in different depths.So that to establish the mechanism model of cutting process of graphite materials.Conclusions:Both normal rake angle and relief angle should be 8°;the kind of graphite who is harder?higher breaking strength and smaller granularity is more suit for high-accuracy part;The depth of cutting can affect cutting process seriously.Little chips will be found when using less depth(0?0.06mm),little chips and little bulk in moderate depth(0.06?0.10mm)and big bulk in larger depth(0.10-0.16mm).On milling:(1)To concluded the influence of cutting forces and machined surface roughness on the conditions of up-milling and down-milling by each cutting parameter through the way of single factor experience of milling.To establish theoretical formula of cutting forces through orthogonal experiment and verify its reliability.(2)To study the laws of cutting forces,surface roughness after machined and cutter wear of each coated tool under different ways of cutting and conditions through single experiment and wear experiment by using uncoated carbide,TiAlN coated and several diamond coated end milling cutter cutting graphite materials under the different conditions of up-milling or down-milling,with or without blowing condition.(3)To optimize the angle of each kind of coated tools through single experiment and wear experiment by using uncoated carbide,TiAIN coated and several diamond coated end milling cutter and milling different kinds of graphite by TiAIN coated tool.Conclude:High cutting speed?big feed per tooth?little radial depth of cutting and axial depth of cutting should be adopted in rough machining graphite and high cutting speed?small feed per tooth?small radial depth of cutting and axial depth of cutting for finish machining.(4)TiAIN coat can't extend lifetime for graphite milling cutter.Diamond coat can improve lifetime largely and lifetime of the diamond coat form different manufacturers are small difference;Blow should not be used in finish machining or diamond coated tool.Up milling and down milling are serious different for uncoated tool.And have different performance when using TiAIN coated tool in big depth of cutting.But not for DIA diamond coated tool.(5)The angles of milling cutter for graphite have been optimized in the paper.The optimize angle of cutter by single fact experiment are 4°for normal rake angle of bottom edge?9° for relief angle of bottom edge?100° for normal rake angle of lateral edge?14° for relief angle of lateral edge and 30° for helical angle.The optimize angle by wearing experiment are 4° for normal rake angle of bottom edge?13°(TiAIN coated)and 9°(diamond coated)for relief angle of bottom edge?5°(TiAlN coated)and 100°(diamond coated)for normal rake angle of lateral edge?15°(TiAIN coated)and 30°(diamond coated)for relief angle of lateral edge and 30° for helical angle.On drilling:To research the influence of drilling parameters on torque,drilling force,temperature of workpiece and drill,chip size and the toughness of hole the wall by single factor experiment of drilling.And to analyze the relationship of drilling parameters with the hole diameter and the broken rate of hole boundary.Also,two methods for diminishing the damage of hole boundary are proposed and their advantage are testified.Conclusions:Torque will decline first and include then with the increasing of feed per tooth.In order to avoid the resonate of machine,the speed should not be 20000rpm.The effect of temperature?roughness of holy wall and diameter of hole by cutting parameter can be ignored.The broken rate of holy boundary will decline first and include then with the increasing of feed per tooth.The best value is 0.04mm/z;strengthed by paraffin on hole can improve quality of hole 40%for exit and 80%for entry.And this method is efficient.