Qualification of the low-pressure cold gas spraying for the additive manufacturing of copper-nickel-diamond grinding wheels

Grinding wheels are usually manufactured by powder metallurgical processes, i.e. by moulding and sintering. Since this requires the production of special moulds and the sintering is typically carried out in a continuous furnace, this process is time-consuming and cost-intensive. Therefore, it is only worthwhile for medium and large batches. Another influencing factor of the powder metallurgical process route is the high thermal load during the sintering process. Due to their high thermal sensitivity, superabrasives such as diamond or cubic boron nitride are very difficult to process in this way. In this study, a novel and innovative approach is presented in which superabrasive grinding wheels are manufactured by thermal spraying. For this purpose, grinding wheel bodies are coated by low-pressure cold gas spraying with a mixture of a commercial Cu-Al2O3 cold gas spraying powder and nickel-coated diamonds (8-12 µm). The coatings were examined metallographically regarding their composition. Afterwards, the grinding wheels were conditioned for the grinding application and the topography was evaluated. This novel process route offers great flexibility in the combination of binder and hard material as well as cost-effective single-part and small-batch production.