Dr. Liu’s research covers a wide range of topics in advanced manufacturing, including tool condition monitoring, machining process optimization and machine process simulation during various kinds of machining processes. Specifically, the tool condition monitoring study is to develop a flexible, cost effective, accurate system to monitor cutting tool conditions and relevant machining situations using machine learning techniques, which is the core theme of his research. The machining process simulation study is to understand, analyze and model the material behavior during various machining processes based on the fundamental cutting mechanics and associated microstructure evolution using both numerical and analytical approaches. His research contributions can be used to optimize cutting conditions to increase the productivity, improve the production quality, and extend the tool life.