Sustainability is one of the challenges in today’s world. With limited resources at hand and hazardous impact of manufacturing processes on the environment, there is an increasing need for sustainable manufacturing. Sustainability actually has a broad meaning and is an all-inclusive concept. In this thesis what we are more interested in and focus on, are energy consumption and environmental impacts. Using system dynamics modeling and simulation, we can more easily understand the behavior of processes. Our selected processes are turning, milling and drilling operations in crankshaft machining and using system dynamics concept we model these processes with regards to energy consumption and environmental concerns. The output of this thesis work can be eventually used as a decision support tool to decide how to make processes more sustainable.