HM-Tool 3D

Material and process optimization of laser-melted carbide structures for the additive production of cutting tools

2023, 68 pages

Project no. 513
Final report

Abstract:

The project followed two development routes based on the current state of research in the additive processing of hard composite materials. One of the development goals is the production of carbide tool bodies that are characterized by higher rigidity and abrasive wear resistance compared to currently used tool steels. For this purpose, WC carbide powders with cobalt and nickel binders are used, which have a higher binder content (83/17) compared to cutting tools. Additive processing is carried out with low energy inputs in order to produce a microstructure that is as defect-free as possible. The porous structures are then sintered. This process route was successfully developed as part of the project. The targets for the mechanical parameters of hardness and flexural strength have been achieved. The good results are demonstrated using a clamping claw with internal coolant supply used in the chip flow. The post-sintering of the open-pored structures has limits due to distortion at high aspect ratios. The second research objective is the additive processing of nickel-bonded titanium carbides (cermets).

The investigations have shown that the coatability of the TiC-30Ni and TiC-15Ni powders used drops significantly at preheating temperatures >700°C. However, when building crack-free additive blanks, the material system requires comparably high preheating temperatures as the WC-Co cemented carbides. Despite various analyses, the cause of the coating problem could not be clearly clarified and could only be remedied to a limited extent with process and material variations. Assembled specimens show that the additively produced TiC-Ni microstructures are significantly more homogeneous and finer-grained than those of tungsten carbide carbides. The microstructures obtained are sufficiently hard, but have insufficient flexural strength due to macroscopic defects from the coating problem. The construction processes are not process-safe with the required preheating temperatures. For this reason, no usable cutting tools could be produced in the project.

The aim of the research project has been partially achieved.