In the machinery manufacturing industry, titanium alloy materials have the characteristics that other metal materials cannot have: high specific strength, high thermal strength, good corrosion resistance;The density of the alloy is only 58% of that of steel, so the thin-walled shell structure made of titanium alloy will become a general workpiece for national defense products.Because the workpiece wall is thin, easy to process deformation, the radial clamping force makes the workpiece produce elastic deformation, tool wear quickly make the processing size is not stable, not easy to ensure the processing quality, the workpiece rejection rate and processing cost is high, workpiece processing deformation has been troubling the technicians and processing operators.
Traditional thin-walled titanium alloy workpiece processing does not pay attention to the selection of tool materials and cutting elements, so that the tool wear fast, deformation increase;Only using a single turning process, instead of following the gradual cycle of stress elimination process technology;The fixture used in processing to eliminate the clamping deformation is not designed properly;After processing and do not pay attention to the dimensional stability of the process measures;The biggest bottleneck of thin-wall titanium alloy workpiece processing is the material difficult to process, dimensional accuracy and shape tolerance requirements, thin wall easy deformation, there are many factors affecting the processing deformation, mainly reflected in the following aspects.
(1) deformation caused by thin cutting heat of workpiece wall
The thermal conductivity of titanium alloy material is less than that of stainless steel and high temperature alloy, the difference of heat dissipation conditions is 1/4 and 1/16 of iron and aluminum, so that the temperature in the cutting area rises rapidly, the product near the cutting edge is not easy to distribute, resulting in stress concentration near the cutting edge, resulting in tool wear and blade collapse, resulting in workpiece deformation.
(2) in the process of workpiece rigid differential cutting, machine tool vibration and cutting factors are not appropriate to produce deformation thin-wall workpiece rigid differential, by machine vibration and other factors caused by the processing of thin-wall titanium alloy workpiece, the cutting speed is not appropriate to produce vibration in the cutting process, resulting in deformation.
(3) deformation caused by radial clamping force during workpiece cutting
When the thin-walled workpiece of titanium alloy is clamped, it is easy to cause elastic deformation under the action of radial clamping force, which affects the dimensional accuracy and geometric tolerance requirements of the workpiece.
(4) during the cutting process, stress release causes deformation
In the process of machining thin-walled titanium alloy workpiece, every time the metal is cut, the stress will be released, resulting in deformation of the workpiece.