Wear Mechanism and Prediction Model of Polycrystalline Diamond Tool in Milling Sand Mould

Zhongde SHAN
2018 Journal of Mechanical Engineering  
单忠德 1 朱福先 1, 2 (1. 机械科学研究总院先进成形技术与装备国家重点实验室 北京 100044; 2. 江苏理工学院材料工程学院 常州 213001) 摘要:针对无模铸造成形技术在铸型制作中的优势,基于聚晶金刚石(Polycrystalline diamond, PCD)刀具铣削砂型试验,研究 了 PCD 刀具铣削砂型的磨损机理,构建了刀具磨损率的预测模型。使用扫描电镜观察了 PCD 刀具刀面磨损带的微观形貌, 研究了刀具磨损随加工时间的变化规律和磨损机理。结果表明:在砂型加工过程中,凸起的砂粒对刀具表面的高频刻划和冲 击导致刀具表面金刚石颗粒解理断裂和金刚石颗粒间黏结材料被刮除,从而造成金刚石颗粒脱落;刀具中的微观缺陷和砂型 中的"硬点"造成刀具微崩刃。基于支持向量机(Support vector machines, SVM)回归分析算法,应用 Matlab 软件编译了 PCD 刀具相对加工量的磨损率回归程序,以正交试验结果为训练样本,构建了刀具磨损率预测模型。应用该模型预测了工艺参数 对刀具磨损率的影响,为砂型高效加工的刀具磨损控制提供了依据。
more » ... 刀具;磨损机理;支持向量机;磨损预测模型 中图分类号:TH16 Abstract:For the advantage of patternless casting technology in mould making, the wear mechanism of PCD tool is studied and the prediction models of wear ratio are built based on the sand mould milling experiments with polycrystalline diamond (PCD) tool. The micro phase morphology of wear zone of PCD tool is observed by scanning electron microscopy, from which the change rule with the processing time and the wear mechanism are studied. The results show that the high frequency scrape and impact of the raised sand particles on the flank during the sand milling process lead to the cleavage fracture of diamond particles and the scraping of the bonding material among the PCD particles in the surface of the tool, which cause the diamond particles to fall off. Furthermore, the microscopic defects in the tool and the "hard spots" in the sand mould cause the cutter micro chipping. Based on support vector machine (SVM) regression analysis algorithm, Matlab is used to compile the regression program of the ratio of wear to milling volume to build the prediction model of wear ratio based on the orthogonal experimental results. The influence of process parameters on tool wear ratio are predicted with the model, which can provide the basis for the wear control of the tool with high efficiency processing sand mould. Key words:patternless casting;PCD tool;wear mechanism;support vector machine (SVM);wear prediction model 0 前言* 挤压-切削一体化无模铸造复合成形技术是快 * 国家杰出青年科学基金资助项目(51525503)。20171008 收到初稿, 20180119 收到修改稿 速成形、数控切削、数字化设计、精密铸造、特种 刀具等技术的集成 [1] 。与传统铸造工艺相比,避免 了模样制作,缩短了铸造流程,实现了单件、小批 量、复杂金属件的快速制造。直接铸型铣削加工是 其关键工艺之一,在砂型铣削加工时,磨损是刀具 的主要失效形式,同时刀具磨损还会严重影响砂型 月 2018 年 9 月 单忠德等:应用 PCD 刀具铣削砂型的刀具磨损机理和预测模型 125
doi:10.3901/jme.2018.17.124 fatcat:bsov3sjwfbfvbkr3vusdmmogom