基于CVD厚膜金刚石刀具的超声振动切削模具钢实验

Ultrasonic Vibration-Assisted Cutting of AISI 420 Mod Steel by Using CVD Thick-Film Diamond Tool

采用化学气相沉积(chemical vapor deposition,CVD)厚膜金刚石刀具进行模具钢超声振动切削实验.首先阐述刀具的材质特点,观测其刀尖微观形貌和切削刃截面轮廓.然后搭建了适应精密/超精密加工需求的超声振动切削实验装置,其中激振机构可稳定实现频率42.0 kHz、振幅峰峰值8～9μm的振动输出.通过切削无氧铜实验证明该超声振动切削装置工作有效、稳定后,选用AISI 420模具钢进行切削实验,研究切削工艺条件及切削用量对加工质量的影响,得到适用于CVD厚膜金刚石刀具的切削用量选取范围,对比研究发现超声振动切削在提升加工表面质量、减少金刚石刀具磨损方面均优于常规切削.本研究可使切削模具钢时的金刚石刀具磨损VB max由500～600μm减少至40μm,模具钢表面粗糙度R a由0.93μm改善至0.09μm.本研究为金刚石刀具超声振动切削模具钢的实用化积累工艺经验,并探索提供可行的技术实现途径.

In this paper, chemical vapor deposition（CVD） thick-film diamond tool was used in ultrasonic vibration-assisted cutting （UVC） process for turning mold steel. Firstly the micro-structure and the edge profile of the tool were observed and discussed. Then a set of UVC experimental outfit was established, and the tool vibrator of the outfit reached a vibration with the frequency of 42.0 kHz and the amplitude of 8-9 μm. And it was testified that the UVC outfit worked well in the oxygen-free copper cutting process. Afterwards, AISI 420 Mod steel was turned on the UVC outfit by using CVD thick-film diamond tool. Dif- ferent machining parameters were experimented, and appropriate parameters fitting UVC turning were ac- quired, also the tool wear and surface finish between UVC turning and conventional turning were com- pared. It was observed that the UVC process in this paper could reduce tool wear VB from 500---600 μm to 40 μm and improve surface finish Ra from 0.93 μm to 0.09μm. This research helps accumulate UVC cutting experience and proposes a hopeful method for diamond tool directly turning mold steels.