铝合金板冲压摩擦试验机开发与试验

Development and experimental of friction tester for aluminum alloy sheet stamping

针对铝合金板冲压成形对摩擦测试的需求,确定考虑加热条件下铝合金板材冲压摩擦伺服压力摩擦测试平台的总体设计方案,开发适用于铝合金板材成形的小载荷高精度多功能摩擦试验机系统。该系统由运动组件、加热系统及控制系统组成。运动组件实现上模具和夹头的运动支撑;加热系统实现模具与试件单独加热;在伺服控制模式下,结合外部力传感器和光栅尺,实现试件压力和模具间隙高精度高稳定性控制。实际应用检验该试验机对不同因素的区分度和重复性,并设计正交试验,探索不同因素对铝合金板材摩擦的影响。结果表明:试验机性能稳定,重复性好;影响摩擦系数因素的重要次序为:模具温度、压力、速度、润滑剂;温度越低,压力越大,速度越快,摩擦系数越小;同一种类型的润滑剂对摩擦系数的影响较小。随着压力的增大,摩擦系数减少的趋势越来越小,逐渐趋于平稳。

The overall design concept of the servo pressure and friction test platform for aluminum alloy sheets under heating circumstances was designed with the aim of meeting the need for friction testing of aluminum alloy sheet stamping.A small-load high-precision multi-functional friction testing machine system suitable for aluminum alloy sheet forming was developed.The system consists of a mechanical system,a heating system and a control system.The mechanical system realizes the movement support of the upper tool and chuck.The heating system realizes the separate heating of tools and specimens.In the servo control mode,combined with the external force sensor and the grating ruler,the force and displacement control double closed loop system is realized,which realizes the high precision and stability control of the specimen pressure and the tool gap.Finally,the orthogonal experiment was designed to explore the influence of different factors on the friction of aluminum alloy blank.The results show that the friction tester has stable performance and good repeatability.The important order of factors affecting friction coefficient is tool temperature,pressure,speed,and lubricant.The lower the temperature,the greater the pressure,the faster the speed,and the smaller the friction coefficient.The same type of lubricant has less influence on the coefficient of friction.The tendency of the coefficient of friction decreasing decreases with increasing pressure and eventually becomes more steady.