Investigation of possibilities for burr minimization in micro milling

• Applicant: Professor Dr.-Ing. Jan C. Aurich
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 544559694

Burrs that occur during micro milling can limit the function of the manufactured component. For micro machining, subsequent deburring is not practical in most cases, as it is very time consuming and cost intensive, and also often causes damage. Therefore, it is essential for micro machining to minimize or avoid burr formation already during machining. For micro milling with tool diameters in the range between 500 µm and 100 µm, it has already been investigated how process parameters, for example the feed per tooth, affect burr formation. Only a few studies have also investigated the influence of the geometry of the tool on burr formation in micro milling. However, comprehensive investigations for tools with diameters ≤ 50 µm are lacking. In preliminary studies by the applicant, it became clear that the helix angle as well as the tilt angle have a significant influence on burr formation during micro milling. However, no comprehensive studies have been conducted showing correlations between the angles and the resulting burr formation. In particular, increased burr formation was observed in commercially pure titanium and stainless steel during preliminary testing. Commercially pure titanium and stainless steel are used e.g. for biocompatible device manufacturing. Burr formation must be minimized, especially for reactors for the cultivation of biofilms. Very high manufacturing accuracy with high surface qualities is essential in the manufacturing, in order to meet the requirements. There is an increased need for research for these products. Based on the preliminary investigations, the helix and cutting edge angles are systematically varied in the experimental studies and the influence on burr formation is investigated. The machining tests will be carried out in commercially pure titanium and stainless steel. In addition to the geometric properties of the tool and the set kinematic conditions, an investigation is carried out at different cutting speeds, which have an influence on material separation due to the different heat input into the material. In order to quantitatively evaluate burr formation on the microscale, a suitable measurement and evaluation methodology for micro end mills with tool diameters ≤ 50 µm will be developed in the project. The basis for this will be scanning electron microscope and confocal microscope images of the resulting burrs. These are evaluated and compared with each other using image processing methods. The project will result in the direct derivation of suitable process parameters for micro milling in commercially pure titanium and stainless steel for the manufacture of reactors for the cultivation of biofilms. In addition, basic knowledge on burr formation during micro milling with tool diameters ≤ 50 µm is generated, which can also be transferred to other applications.

• DFG Programme: Research Grants