Paper Title
Influence of Steel Alloy in Different Hardness on The Machining Results in Ultrasonic Assisted Diamond Turning

Abstract
This paper focuses on ultra-precision machining on steel alloys in different hardness with single crystal diamond tools. Steel parts are useful in many applications such as injection moulding for optical parts because of their mechanical properties. However, steel cannot be directly machined by diamond tools due to the extensive tool wear. Studies have proven that with the use of ultrasonic assisted technique, steel can be successfully machined by the diamond tools. Meanwhile, the influence of the hardness on the surface quality on the machined steel parts is unknown, and it is the main focus of this paper. The experimental results show that with the use of ultrasonic assisted diamond turning on steel alloy, surface roughness as low as 3nm can be achieve on hardness 34 HRC sample, and the trend is V-bottom shape, with higher values on either end and lower values in the middle. Keywords - Ultra-precision Machining, Steel Alloy, Hardness, Ultrasonic Assisted Machining, Mould Manufacturing