三自由度串联式快速刀具伺服刀架的研究

Study on Three Degrees of Freedom Tandem Fast Tool Servo Device

快速刀具伺服金刚石车削被认为是针对光学自由曲加工方法中非常有发展潜力的超精密加工技术。针对目前三自由度快速刀具伺服刀架在X、Y、Z3个方向上存在运动耦合、导致在刀具路径规划困难以及影响刀具使用寿命的问题,提出一种新型三自由度串联式快速刀具伺服刀架,通过将X、Y、Z3个方向的运动串联,避免了X、Y、Z 3个方向运动解耦困难;通过分析三自由度快速刀具伺服刀架应具备的要求,确定柔性铰链截面形状、材料以及尺寸;运用ANSYS对该三自由度串联式快速刀具伺服刀架进行有限元分析,得到X、Y、Z3个方向柔性铰链最大应力均远小于材料的许用应力,前6阶振型共振频率远高于伺服刀架的工作频率。结果表明,该刀架满足实际车削过程中的内应力和共振频率要求。

Diamond turning based on fast tool servo （Frs） is considered to be a very potential ultra-precision machining technology for fabricating the optical free form surfaces. The current three degrees of freedom FI＇S has the problem of motion coupling, resulting it is difficult to plan tool path and the tool life is affected. A novel three degrees of freedom tandem FTS was presented. By the move- mentseries on X, Y, Z directions, the diflqculty of motion decoupling in X, Y, Z directions was avoided. Analyzing the requirements of three degrees of freedom FTS should have, the cross^sectional shape, material and sizes of the flexible hinge were determined. The fi- nite element simulation of the three degrees of freedom tandem FTS device was made by using ANSYS. It is shown that the maximum stresses at X, Y, Z directions of the flexible hinge are much smaller than the material allowable stress, the resonance frequencies of the first six vibration modes are much higher than the working frequency. The results show that the stresses and the resonance frequencies of the device meet the application requirements.