单点金刚石车刀微槽型结构设计及其高精度、近无损伤制造方法

Single point diamond turning (SPDT) is widely used in the manufacturing of ultra-smooth surface. The structure of SPDT cutting tool influnces the generation of machined surface and tool life greatly. Existing structure of diamond cutting tool is very simple due to high hardness of diamond materials. Generally the complex chip breaker and special texture are difficult to be machined on the surface of SPDT cutting tool. With the range extension of cutting processes and workpiece materials, the requirement of chip control during SPDT is improved. However, Simple geometrical structure of cutting edge of SPDT is difficult to achive the precision machining requirement. In this study,the relationship between workpiece material flow and geometrical structure of SPDT cutting tool has been built on the basis of dynamic properties and coordination deformation of microstructure of workpiece materials. The structural parameters of micro-groove of SPDT cutting tool have been designed by the aid of finite element method. The material removal mechanism of polycrystalline/monocrystalline diamond materials during the machining processes with laser and focused ion beam has been studied respectively. The machining methods of micro-groove on the polycrystalline diamond and monocrystalline diamond cutting tool have been studied. The SPDT experiments have been performed to validate the performance of micro-groove of diamond cutting tool.

单点金刚石切削广泛应用于超光滑高精度表面的制造，而单点金刚石刀具的几何结构对已加工表面的形成和刀具寿命有很大影响。由于金刚石材料硬度高，刃磨难度大，因此现有金刚石刀具的几何结构简单，没有复杂槽型及特殊微刃结构。但是随着单点金刚石切削范围的扩大和加工对象材料种类的增加，对单点金刚石切削过程中切屑流动控制的要求也越来越高，简单的切削刃结构显然难以达到这一目的。本研究以工件材料在微米尺度的动态力学特性和晶粒晶界协同变形行为为基础，建立工件材料流动特性和单点金刚石刀具微刃几何结构之间的关系，借助切削过程数值仿真技术设计相应的微槽型。研究激光束和聚焦离子束加工条件下金刚石材料的去除机理，提出聚晶金刚石刀具和天然金刚石刀具微槽型的加工工艺流程和方法，探讨槽型几何结构的高效精确成型方法及金刚石刀具变质层的控制方法。最后利用单点金刚石切削试验进行不同微槽型金刚石刀具的加工性能和加工效果对比。

搭建了微射流水导激光加工平台，探讨了水导激光加工过程的材料去除机理。分别利用微射流水导激光加工、飞秒激光加工、激光诱导等离子体辅助加工三种方法对金刚石进行加工测试，得到了金刚石刀具微槽型加工的最优方案。自主搭建了一台立式超精密车床，利用加工得到的金刚石刀具进行了三种不同晶粒度无氧铜的超精密车削试验，建立了三种无氧铜材料动态力学性能和加工性能的关系，并以此为基础优化了加工工艺参数。最后将单点金刚石超精密车削技术应用于新型摩擦试验机的搭建，实现了少磨合的高速摩擦试验方法。