Chandula Wickramarachchi

I am an Engineering Doctoral (EngD) student at the University of Sheffield working closely with the DRG and the Industrial Doctoral Centre (IDC) in Machining Science which is part of the Advanced Manufacturing Research Centre (AMRC). My EngD is a four year degree which is sponsored by Element Six Ltd. and EPSRC. I did my masters at the University of Sheffield in Aerospace Engineering with a focus in aeromechanics. During the degree, I completed a 15 month placement in the machining group at Nuclear AMRC working as an assistant project engineer. Subsequently, my interest in machining and condition monitoring grew further when I undertook a project on portable machining conducted by Rolls-Royce. 

Research interests

My research interests are in condition monitoring, dry turning with Polycrystalline cubic Boron Nitride (PcBN) tools, understanding and modelling tool wear and the mechanics of chip formation. 

Current research

Currently I am working on building a detailed knowledge of chip formation and tool wear mechanisms in turning which includes finite element modelling of the tool and work-piece interactions for the relevant materials. 

I am planning to design and build a test rig for unmanned cutting tool testing using a lathe, where automatic tool wear inspection, surface finish measurement and process monitoring systems are integrated within the operation. 

I am also conducting statistical analysis of experimental data to identify tool wear trends and process robustness. The techniques I have used so far include multiple linear regression, auto regressive models, moving average auto regressive models and novelty detectors. 

Above: The images are taken from a machining trial where case hardened steel is dry turned using PcBN tooling. The high temperatures reached by the tool can be seen as sparks are generated. Thermocouple which were placed inside the tool captures these temperatures. 

The above image shows the results of an autoregressive model used to predict force data collected from a machining trial where PcBN was used to machine case hardened steel.