Effect of manufacturing parameters on polycrystalline diamond compact cutting tool stress-state

• To avoid detrimental stresses, the pressure/temperature ratio during cooling down should be below 0.007 GPa/K.
• Stress transients during PDC tool manufacturing are 2–3 times higher than steady-state values.
• High stress transients lead to the formation of micro-cracks and premature failure of the PDC tool.
• Low to moderate cooling rates and gradual pressure removal following PDC sintering are preferred.

Residual stresses and stress transients in a polycrystalline diamond compact tool were numerically predicted for different pressure and temperature manufacturing conditions. Results showed maximum tensile and compressive stresses of about 500 MPa and − 125 MPa, respectively. However, stress transients during the manufacturing process were up to 2–3 times higher. These depend on how pressure and temperature are removed following the sintering process. Rapid cooling and pressure removal result in high stress transients and vice-versa. These transients can lead to the formation of micro-cracks and delamination of the polycrystalline diamond layer from its substrate, contributing to premature failure of the tool. On the other hand, lower cooling rates and gradual pressure removal offer low stress transients and a favourable final residual stress-state of the PDC tool.

(a) Maximum normalised tensile residual stress transients during cooling down for high (profile 1), intermediate (profile 2) and low (profile 3) cooling rates, and (b) peak stresses for different pressure–temperature (P–T) conditions showing regions of high and low risks of PDC tool failure.Figure optionsDownload as PowerPoint slide