阶梯型复合刀具CVD金刚石涂层制备工艺及应用研究

Study on Preparation and Application of Ladder Compound CVD Diamond Coated Tools

针对加工阶梯孔类的阶梯型复合刀具,采用热丝辅助化学气相沉积技术(HFCVD),通过超声辅助酸碱两步预处理法,并且采用钽丝上下两层平行布置的沉积装置,调节生长参数,研究了YG6硬质合金阶梯型复合刀具的金刚石涂层制备技术。为了研究涂层性能,以含少量石棉的复合纤维刹车片作为加工对象,分别对比实验了金刚石涂层和未涂层刀具的钻削性能。结果表明:相对传统单层热丝沉积工艺,采用双层热丝布置方式,在涂层过程中能使切削刃各个部分的温度保持平衡稳定,使得阶梯复合刀具每个切削刃都能均匀地涂上一层金刚石薄膜。采用该方法沉积的金刚石涂层阶梯复合刀具在钻削过程中具有良好的切削性能及附着强度,特别是在高速加工中金刚石涂层阶梯复合刀具在轴向钻削力及扭矩方面都小于未涂层刀具,金刚石涂层阶梯复合刀具在钻削刹车片阶梯复合孔加工中具有显著的优势。

For the ladder compound tools which are used in stepped holes machining,by using the technology of Hot Filament Chemical Vapor Deposition（ HFCVD） and adjusting the growth parameter,the diamond coating preparation technology of YG6 carbide ladder compound tools were investigated by the method of two-step ultrasonic assisted acid-alkali etching pretreatment and the deposition apparatus with tantalum wire on two layers arranged in parallel. In order to evaluate the coating effect,drilling experiments were performed on composite fiber brake pads with a little asbestos to comparatively examine the drilling performance of diamond coated tools and uncoated carbide tools. The results shows that the temperature of cutting edge in various tool parts can keep balanced and stable during the coating process by using the deposition apparatus when double hot filament are adopted,and the uniformity of diamond films deposited on the ladder compound carbide tool is better than the single layer hot filaments adoption in the conventional deposition process. Diamond coating ladder compound tools which are deposited by this method can keep a good cutting performance and adhesion strength in the drilling process. Especiallythe axial force and torque drilled by ladder compound diamond coated tools are smaller than the uncoated tool. Diamond coated ladder compound tools hold an obvious advantage in the drilling process of brake pads ladder compound hole.