The Study Of Adjustable Chip Breaker And Chip Breaking Method For PCD Tools

PCD tools are widely used in the precision machining of aluminum alloy metals.However,there is one problem that the chips tangle with the workpiece or cutting tool during the processes of cutting for PCD tools.This chip winding phenomenon may cause some serious problems such as reducing the surface accuracy of the workpiece,shortening the tool life and increasing the production cost.To solve the problem of chip winding,the chips need to be broken regularly.A chip breaker with position on rake face of tool can be adjusted was designed,which can break the chips regularly.According to the structure and installation features of the PCD insert,structure of the chip breaker was designed.The comparison experiments of chip breaker,chip breaking groove and non-chip breaking measure for PCD tools were carried out.Through finite element simulation and cutting experiments,the influences of chip breaker parameters on the radius of chip curl curvature were analyzed.Forces on chips and the chip breaking processes of PCD tool with chip breaker were analyzed.The geometric relationships between chip breaker and chip were established.According to the geometric relationship and the chip breaking criterion,the formulas of three chip breaker parameters were deduced.The application of the chip breaker can expand the chip breaking range of cutting parameters for PCD tools,compared to the chip breaker groove,and C-shape chips can be produced regularly.The radius of chip curl curvature decreases as the inclination angle increases and decreases as the position parameter decreases.There is a threshold for both inclination angle and the position parameter of the chip breaker,and if the threshold is exceeded,severe noise and chip build-up will occur.The influence mechanisms of chip breaker on chip breaking are obtained.The chip breaker can promote chip curling.However,if the chip cannot be broken after touching the workpiece or tool,the radius of chip curl curvature will still increase,and it is easy to turn over and perform a spiral movement,making the chip difficult to break.If the contact point between the chip and the chip breaker is located in the selected segment of chip,the extrusion force between the chip and the chip breaker will increase as the chip grows,which can cause the chip to be cracked and broken easily.The selected segment of chip that the chip is easy to be broken is determined.According to the selected segment of chip and the derivation of geometric relations,a simple set of equations are established for designing chip breaker parameters,including inclination angle,position parameter and height.A design method for chip breaker parameters of PCD tool is presented.