Diamond Insert Wear when Turning Rapidly Solidified Aluminium RSA 443 of High-Silicon Content

Abstract:

Rapid solidification of molten metals has been recently used to generate a new group of alloys having ultra-fine microstructures and high end mechanical properties. Therefore, such alloys can be successfully used in the optics industry to produce diamond machined mirrors and mould inserts for plastic lens injection. Rapidly solidified aluminium grades characterised by their ultra-fine grains can be used to replace traditional optical aluminium such as 6061-T6 which has coarse microstructure when making optics. However, there is currently no data available on the performance of these new grades in terms of diamond tool wear when machined in single-point diamond turning operation. This paper reports on the wear mechanisms of natural diamond tools when turning RSA 443 which is a new aluminium grade produced by rapid cooling process. Although this new aluminium grade enjoys fine microstructure, it is harder than traditional optical aluminium because of its increased content of silicon (about 40%). Therefore, there is a need to establish a deeper understanding of diamond tool performance when using diamond turning of optical components from this material. In this study, three machining parameters, namely cutting speed, feed rate, and depth of cut, were varied at three levels and the edge wear of the diamond inserts was observed using scanning electron microscopy after 4 km of cutting distance. The first observations from this preliminary study show that tool wear of diamond is more sensitive to the change in cutting speed than it is for other cutting parameters. Wear is relatively high (12 µm) at the lowest cutting speed (500 rpm). However, at high cutting speed (3000 rpm) the edge wear was small (3 µm). This could be attributed to the increased impacts of cut the material on the cutting edge. The study also reports on the surface finish obtained at the different combinations of cutting parameters.

• Periodical: Materials Science Forum (Volumes 828-829)
• Pages: 265-271
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.828-829.265
• Online since: August 2015
• Authors: Zwelinzima Mkoko, Khaled Abou-El-Hossein*
• Keywords: Diamond Tool Wear, Machining of Aluminium, Optical Aluminium, Rapidly Solidified Aluminium, Scanning Electron Microscopy, Surface Roughness, Ultra-High Precision Machining

References

[1] (RSP Technology), RSP technology [online]. http: /www. rsp-technology. com/ (2015) [last accessed 02. 02. 15].

[2] Z.W. Zhong, M.H. Leong, X.D. Liu, The wear rates and performance of three mold insert materials, Materials and Design 32 (2011) 643-648.

DOI: 10.1016/j.matdes.2010.08.008

[3] G. Gubbels, L. Tegelaers, R. Senden, Melt spun aluminium alloys for moulding optice, Proc. SPIE 8884, Optifab (2013), Rochester.

DOI: 10.1117/12.2030181

[4] S. Zare Chavoshi, Tool flank wear prediction in CNC turning of 7075 AL alloy SiC composite, Prod. Eng. Res. Devel. 5 (2011) 37-47.

DOI: 10.1007/s11740-010-0282-x

[5] M. Shi, B. Lane, C.B. Mooney, T.A. Dow, R.O. Scattergood, Diamond tool wear measurement by electron-beam-induced deposition, Precision Engineering 34 (2010) 718-721.

DOI: 10.1016/j.precisioneng.2010.03.009

[6] B.M. Lane, M. Shi, T.A. Dow, R. Scattergood, Diamond tool wear when machining Al6061 and 1215 steel, Wear 268 (2010) 1434-1441.

DOI: 10.1016/j.wear.2010.02.019

[7] K. Abou-El-Hossein, O. Olufayo,Z. Mkoko, Diamond tool wear during ultra-high precision machining of rapidly solidified aluminium rsa 905, Wear, 302(1) (2013) 1105-1112.

DOI: 10.1016/j.wear.2012.12.060

[8] P.H. Guido P.H. Gubbels, Bart W.H. van Venrooy, Albert J. Bosch, Roger Senden, Rapidly solidified aluminium for optical applications, Proc. Of SPIE Vol. 7018 (2008) 70183A-1.

DOI: 10.1117/12.788766