Investigation of turning elastomers assisted with cryogenic cooling

Elastomer components are normally produced by a molding process. When it comes to small batch sizes this becomes inefficient due to the expensive production of the molding tool, and machining is an economic alternative. However, due to the very low Young's modulus elastomers are difficult to machine. The investigated approach to enhance machinability was to use cryogenic cooling during cutting elastomer components, changing their mechanical properties. Experiments in turning show that elastomers do not respond like ordinary metal materials. Hence this study is conducted to describe the effects occurring during turning elastomers assisted with cryogenic cooling. Therefore extensive tests were carried out to determine the material characteristics. Forces and tool temperatures were measured in turning tests. A rise in tangential cutting force by approximately 30% compared to dry machining verifies the change in material properties at very low temperatures. This correlates with the measured tensile strength at different temperatures. The examined surface integrity and the formed chips confirm the improvement in machinability under cryogenic conditions as a result of lower material deformation. In addition the friction between tool and chip was evaluated by applying a temperature dependent friction law