高速铣削航空铝合金7050-T7451时刀具的磨损破损

TOOL WEAR AND FRACUTRE IN HIGH SPEED MILLING ALUMINUM ALLOY 7050-T7451

分析涂层硬质合金刀具高速铣削航空铝合金7050-T7451时的磨损、破损形态,通过正交试验研究了高速铣削航空铝合金的铣削力及其变化规律,提出模拟高速铣削刀具裂纹萌生的脉冲激光热冲击试验方法,研究铣削力和热应力在刀具磨损、破损过程中的不同作用。试验和理论分析证明:高速铣削航空铝合金7050-T7451时,热应力使刀具萌生裂纹,裂纹在热应力和机械应力综合作用下扩展。研究刀具失效机理,证明:高速铣削航空铝合金时,粘结磨损和扩散磨损是主要磨损机理。提出通过提高切削系统稳定性和优化切削参数,可以有效降低机械应力对刀具的冲击作用,并在生产现场收到良好的效果。

Wear and fracture mechanisms are revealed in highspeed milling aluminium alloy 7050-T7451 based on experimental and theoretical research. A new method is presented to reveal crack initiation of cutting tool by impulse laser simulation. The different roles of milling forces and thermal stress in tool failure are studied. The results prove that crack initiation is caused by thermal stress while is expanded by thermal and mechanical stresses in high speed milling aluminium alloy 7050-T7451. Failure mechanisms are investigated and adhesive and diffusion are main wear mechanisms. To decrease the impact of mechanical stress on milling tools, measures are presented that stability of machining system should be tested and cutting parameters should be optimized, which have been employed in workshop and the fact prove that tool breakage decrease remarkably.