Experimental Study On The Influence Of Mechanical Properties Of Cutting Tool Shim On Cutting Tool Wear And Damage Performance

The shim is an important part of the machine-clamped indexable tool.It is installed under the blade.Its main function is to absorb the mechanical(force)impact of the blade during cutting and provide the blade with good positioning accuracy.In the process of part milling or intermittent cutting,due to the change of cutting force,it will cause force impact on the blade,which will increase the wear of the tool and cause sudden damage such as chipping and peeling of the blade,which will affect the processing quality of the workpiece.and production safety.In this paper,intermittent cutting experiments are carried out on tools equipped with shims of different materials to explore the influence of the mechanical properties(elastic modulus)of the shims on the wear and damage performance of the tool.The indexes such as cutting force,tool wear and breakage of different shims during intermittent cutting are analyzed,providing basic data reference for in-depth understanding of the mechanical properties of the shim on the tool(blade)in interrupted cutting and the optimal design of the shim.The main research contents and conclusions of this thesis are as follows:Firstly,YG8 cemented carbide tools were used,and interrupted cutting experiments were carried out when YT14 cemented carbide,08 steel,TC4 titanium alloy and N8 aluminum alloy shims were installed.The cutting force in the cutting process was measured,the tool wear morphology was observed,and the mechanism was analyzed,and the influence of the mechanical properties of the shim on the wear of the cemented carbide tool was studied.The results show that the impact force of the tool with 08 steel,TC4 titanium alloy and N8 aluminum alloy shims is significantly smaller than that with YT14 cemented carbide shims;when the tool is equipped with four different material shims The wear morphology is similar,with scratches and pits on the rake face,furrows,material bonding and boundary wear on the flank face.The wear mechanisms are mainly abrasive wear,adhesive wear and oxidative wear.However,the degree of wear is different.When the tool uses a YT14 carbide shim,the boundary wear at the secondary cutting edge of the tool is lighter,the workpiece material adhered to the rake face is less,and the coating peeling area is small.When the 08 steel,TC4 titanium alloy and N8 aluminum alloy shims are installed,the wear amount of the tool flank is small,but the boundary wear at the secondary cutting edge is serious,and the workpiece material adhered to the rake face is more and the peeling area of the coating is large.Secondly,using YG8 carbide tool,under the condition of four different material shims,intermittent cutting is carried out at fixed feed rate,different cutting amount,and different spindle speed,and the mechanical properties of the shim on the impact of the tool are studied.The effects of breakage and fatigue damage.The results show that when the fatigue damage experiment is carried out,cracks first appear on the coating of the insert that participates in the cutting part.As the cutting progresses,the coating peels off and exposes the base of the insert,so that the base of the insert participates in cutting,and then the base of the insert is cracked.Fatigue cracks occur and fatigue damage occurs.The tool damage size when 08 steel,TC4 titanium alloy and N8 aluminum alloy shims are installed is slightly larger than that when YT14 carbide shims are installed.In the impact damage test,when the depth of cut is 0.4mm,the tool breaks when the YT14 carbide shim is installed,but does not break when the 08 steel,TC4 titanium alloy and N8 aluminum alloy shims are installed.When the depth of cut is 0.6mm,the tool shims with four different materials are broken,and the fracture is relatively rough,with a stepped fracture,which is a brittle fracture under mechanical impact.Finally,using ceramic and PCBN tools,intermittent cutting experiments were carried out under the condition of four different material shims respectively.Influence of wear and tear on ceramic and PCBN inserts.The results show that the impact force of ceramic and PCBN cutters with 08 steel,TC4 titanium alloy and N8 aluminum alloy shims is significantly smaller than that with YT14 carbide shims.The wear morphology of the ceramic tools equipped with four different shims is similar.The rake face has crescent craters,material bonding and wear of the main and auxiliary cutting edge grooves,and the flank face has furrows and material bonding.The wear mechanism is mainly For abrasive wear,bonded wear and diffusion wear.The wear morphology of PCBN tools equipped with four different material shims is also similar.The rake face is crescent crater,material bonding and groove wear of the main cutting edge,and the flank face is furrow and material bonding.The wear mechanism Mainly for abrasive wear and bond wear.When the depth of cut is 1mm,the 08 steel,TC4 titanium alloy and N8 aluminum alloy shims can slow down the wear and damage of ceramic and PCBN tools,and obtain better cutting performance.At depths of cut 1.2 and 1.4mm,ceramic and PCBN tools can have long tool life with YT14 carbide shims.