Investigation of the critical cutting edge radius based on material hardness

详细信息    查看全文

• 作者：M. Azizur Rahman ; M. R. Amrun ; M. Rahman…
• 关键词：Micromachining ; Cutting edge radius ; Relative tool sharpness (RTS ; a/r) ; Extrusion ; like mechanism ; Material hardness ; Surface finishing
• 刊名：The International Journal of Advanced Manufacturing Technology
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：88
• 期：9-12
• 页码：3295-3306
• 全文大小：
• 刊物类别：Engineering
• 刊物主题：Industrial and Production Engineering; Media Management; Mechanical Engineering; Computer-Aided Engineering (CAD, CAE) and Design;
• 出版者：Springer London
• ISSN：1433-3015
• 卷排序：88

文摘

This paper is aimed to investigate the influence of material hardness on the behaviour of cutting edge radius in tool-based micromachining process. The main governing process parameter considered for this study is relative tool sharpness (RTS) which is quantified as the ratio of undeformed chip thickness (a) to tool edge radius (r). The variation of RTS influences the chip formation behaviour with transition from concentrated shearing to ‘extrusion-like’ mechanism for achieving ‘grinding-like’ surface finishing by the extensive tool edge radius effect. As different materials have different characteristics and properties, the critical threshold RTS value (RTS_critical) may vary with material hardness by significantly affecting the surface topography during ‘extrusion-like’ mechanism. In this study, material hardness is found to be an important mechanical property in orthogonal micro turning experiments conducted with a CBN tool for metal alloys. Best finishing (R_a) values of workpiece surfaces were used to determine the material hardness effect on RTS_critical. Firstly, Aluminium and Magnesium alloys were used to construct a graphical trend for the relationship of material hardness and relative tool sharpness. Secondly, a random material was selected to predict the RTS value from the graphical trend based on material hardness. Thirdly, micro turning experiments were conducted to validate the predicted result. Finally, the graphical trend was updated to get the relationship of material hardness and critical relative tool sharpness (RTS_critical) with the three experimental materials which are most widely used in micromachining industries.