Meaning
Conical metal washers provide high mechanical resistance within very short axial travels. In heavy injection tooling assemblies, belleville disc springs maintain secure clamping forces on bolts that experience extreme temperature changes. The conical profile generates a predictable, progressive spring rate during compression.
Force Behavior
A non-linear load deflection relationship governs these specialized fasteners. Stacking the elements in series increases the available deflection, while stacking them in parallel multiplies the force capacity. This modular behavior allows custom adjustments for thermal expansion without redesigning the cavity plate.
Thermal Action
Constant pressure across the runner manifold prevents polymer leakage when temperatures reach high operating states. Because the steel expands during heat-up, belleville disc springs compress slightly to absorb the displacement and keep the clamping force from rising to destructive levels. This action prevents thread stripping and plate distortion.
When the tool cools, the springs expand to maintain a secure seal that prevents molten plastic from seeping into the surrounding channels.
Sizing Threshold
Mechanical travel of the washer must never reach complete flatness during operation. If the stack is compressed past its designated limit, the spring becomes a solid spacer and loses its compensating action. That loss results in flashing or component breakage.
