Promotion of Cutting Performance and Tool Life for Hardened Mold Steel Machining Through Green Manufacturing Technology

摘要

This study applies the green manufacturing technology to promote the cutting performance and tool life for hardened steel machining. First, milling experiments were arranged with different process parameters such as cutting speeds, feed rates, axial cutting depths and radial cutting depth. Each combination set is further combined with different lubricant environments such as various flow rates of minimum quantity lubrication (MQL) and dry cutting conditions. During the milling processes, the cutting forces and cutting temperature were measured using a dynamometer and a thermal imager, respectively. After material removed from the workpiece in each process parameter combination set, non-contact surface roughness instrument and tool microscope are used to measure the surface roughness and tool wear, respectively. The results show that with too much or too little lubricant amount, the damage from the thermal fatigue is easily deduced in cutting tool. While an appropriate amount of lubricant can reduce the tool wear, help to prolong the tool life and cause the cutting forces obtained being smaller than dry cutting. Although, the surface roughness obtained from MQL cutting situation is not better than that in dry cutting, MQL is still a good option for hardened mold steel milling if the tool life is the priority choice and the surface quality may be within the allowable range, since MQL can always improve the tool life from both the good actions of cooling and lubrication. From the synthesis results and investigations, it shows that an appropriate selection of cutting parameters and flow rates for MQL, the tool life will get some extent of improvement because of MQL has stable lubrication and cooling actions. MQL can deal with the environmental pollution and harmful human health from the use of flood cutting fluid conventionally, and fulfill the lubrication and cooling requirements of green environmental protection manufacturing.