Tuyển tập các báo cáo nghiên cứu khoa học trên tạp chí khoa học vật lý quốc tế đề tài: WEAR MECHANISM OF TiN, TiAlN AND TiCN COATED DRILLS DURING DRILLING OF CARBON STEEL | Journal of Physical Science Vol. 18 1 75-85 2007 75 WEAR MECHANISM OF TiN TiAlN AND TiCN COATED DRILLS DURING DRILLING OF CARBON STEEL . Talib . Toff and . Ariff AMREC SIRIM Bhd. Lot 34 Jalan Hi-Tech 2 3 Kulim Hi-Tech Park 09000 Kulim Malaysia Corresponding author talibria@ Abstract This study is to investigate the wear mechanism develops during drilling of High Speed Steel of molybdenum type drill 5 mm in diameter coated TiCN TiN and TiAlN on the medium carbon alloy steel work piece. The performance tests were conducted on CNC milling machine at spindle rotation of 1 600 rpm and feed rate of 20 mm min. A carbon steel plate with a thickness of 30 mm was used as a work piece and the depth of drill was set at 25 mm. After drilling the microstructural changes on each coated drill were observed under the scanning electron microscopy SEM . In this paper the wear mechanism operated during drilling was discussed. Generally wear mechanism operated during drilling were found to be a complex combination of abrasive adhesive and thermal wear. Keywords coated drill performance test tool life wear SEM microstructure 1. INTRODUCTION A compound coating such as TiCN TiVAlN TiZrN TiAlN is used to increase the tool life of the cutting tool. It also improves microhardness wear resistant corrosion resistant operating life and productivity electrical properties and optical properties of engineering components. Previous study by earlier researchers showed that an increase in tool life may be due to the following phenomena i increase in hardness 1 ii greater bonding energy of the coating elements 2 and iii lower friction This hard coating can be applied to cutting tool mould and dies machine elements automotive parts electrical and electric components. Shizi et reported on average an eight-fold lifetime increase of 2 to 3 pm thick Plasma Assisted Chemical Vapour Deposition PACVD coated thin layer twist drill as compared to uncoated drills. On another
