Meaning
Thermal treatment designed to reduce the internal tensions created during the machining or welding of a tool. Stress relieving involves heating the steel to a temperature below its critical point and holding it there before cooling it slowly. This stabilizes the metal so that it does not warp during the final stages of grinding.
Dimensional Stability
Relieving the internal strain ensures that the cavity maintains its shape when exposed to the heat and pressure of injection moulding. Without stress relieving, a tool might distort over time, leading to flash or part mismatch. This process is particularly important for large or complex mould bases.
Heat Timing
Best results come from performing the heat cycle after rough machining but before the final finish cuts. Stress relieving allows the metal to move into its relaxed state while there is still enough stock to correct any movement. This sequence prevents the loss of precision in the finished cavity.
Component Longevity
Removing the residual stresses reduces the likelihood of spontaneous cracking under load. Stress relieving is also used on moulded plastic parts to prevent environmental stress cracking in the field. For both metal and plastic, it is a safeguard against premature failure.
Proper thermal cycling ensures the long-term accuracy of the production equipment.
