The sintering process is a crucial step in the production cycle of cemented carbide inserts where dimensional accuracy is challenging. This work is to study in detail the critical aspect of shape stability of sintered bodies in cemented carbide tools where the filling direction of the green bodies has been taken into account.

The research begins with a literature review of existing reports, summarizing key findings, and identifying gaps in current knowledge. In collaboration with Seco R&D and production experts, suitable powder grades (5.5 – 9.0 % Co; fine to medium coarse WC) were selected for the investigation. A carefully designed experiment, planned in consultation with stakeholders, was conducted to explore sintering methodologies. Sintering experiments with positioning of inserts in the furnace as well as different heating and cooling effects were also made.

To ensure accurate and reliable results, the most appropriate measurement technique was established in collaboration with measurement experts. An extensive and structured sample measurement was performed to build a robust database for analysis. The results were then analyzed by using Modde13 to identify the primary factors contributing to the shape quality of the inserts.

Through the interpretation of the interplay of various variables in the data, meaningful insights were derived to quantify shape distortion. It was observed that the shape distortion is not sensitive to the angle between press direction and furnace direction or tray location. Also, the geometry of the inserts played a stronger role than sintering recipes selected. The findings of this report provide a deeper understanding of the factors influencing shape quality in the sintering process, offering valuable guidance for future production improvements.