Pretreatment of micro carbide tools prior to coating by blasting with solid carbon dioxide

• Applicant: Professor Dr.-Ing. Eckart Uhlmann
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 433825513

So far, blasting with solid carbon dioxide is mainly used for cleaning operations of workpieces. In this project, the suitability for substitution of the conventional process chain with all pre-treatment, cleaning and post-treatment processes for the coating of micro carbide tools is investigated. The aim is to create a technological basis for the influence of dry ice blasting on the adhesion strength of PVD coatings and thus on the tool life of coated tools. For this purpose, carbide workpieces are machined by blasting with solid carbon dioxide and the coating properties are compared with conventionally cleaned and pre-treated workpieces. Since CO2 can only be present in a solid or gaseous phase at ambient pressure, the abrasive sublimates after hitting the substrate, so that no residues remain on the workpiece surface and no disposal of the abrasive is necessary. Compared to conventional pre-treatment processes, the process is therefore considered residue-free. Experimental investigations on semi-finished carbide products are carried out with statistical test planning. An empirical process model serves as the basis for a model for the mathematical representation of the functional relationships between the input parameters and the generated surface and coating parameters. The knowledge gained on blasting with solid CO2 as a pretreatment, cleaning and post-treatment process for PVD-coated carbide workpieces will finally be transferred to carbide tools, in particular micro milling cutters.

• DFG Programme: Research Grants