Increase of process reliability of ultra-precision cutting through direct temperature measurement in cutting parts form single crystal diamond by use of Boron-doping

• Applicant: Professor Dr.-Ing. Eckart Uhlmann
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering ; Production Automation and Assembly Technology
• Term: from 2016 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 317330168

Ultraprecision machining is an established process for manufacturing of optical components for automotive, medical or aerospace applications. The use of single crystalline diamond tools (SCD) with cutting edge radius rβ ≤ 50 nm realise optical and functional surfaces such as mirrors, gratings or lenses. Despite the high mechanical hardness of diamond, there are wear phenomena during the cutting process. To characterize und interpret the wear processes of the diamond in the cutting zone, cutting temperatures need to be analysed. Currently, the temperature on a diamond tool is not fully investigated. The lack of suitable temperature measurement methods regarding resolution and response time are the reason for this new approach. The aim of the project is to measure the temperature in the cutting zone of the diamond. This is done by the use of the electrosensory features of the ion beam boron-doped diamond tool which enables a direct measurement in the cutting zone of the diamond tool without delay time. The results from the first working periode indicates that the basic operability from ion implanted diamond tools to measure the temperature is possible. Yet, there is no possibility to measure the temperature in the cutting zone since the distribution of the Boron is too inhomogeneous. Therefore, the aim of the second working periode is to use a more accurate method to introduce structures with a defined shape into the diamond. The advantages from this method are a higher sensitivity of the temperature measurement in the cutting zone, avoidance of strong bursts of the diamond and a better grindability. The work programm includes an investigation of the features and characteristics of the boron-doped structures and of a possible workwindow for the ultra precision cutting process. A complete measurement setup has to be designed and developed to determine the temperature in the cutting zone. Building on this, experimental investigations are conducted which examine the temperature in the cutting zone. Simultaneously, FEM-simulations are carried out to verify the results.

• DFG Programme: Research Grants