Tool Part Interaction and Residual Stress Evolution in Constrained Post Cure Dwells
Constrained post cure dwells reduce residual stresses only when dwell temperatures exceed glass transition points to enable shear stress relaxation across tools.
De Tooling Gate Condition
Meaning
Physical appearance and fracture quality at the injection or infusion inlet after component ejection determine the structural cleanliness of the trimmed part margin. A clean de tooling gate condition indicates that the matrix material at the sprue separation point fractured crisply without tearing adjacent composite laminates or leaving raised plastic burrs. The evaluation applies to post-cure demoulding operations before secondary machining or deflashing takes place.
Automated ejection runs measure break-off force and surface roughness at the gate scar to verify process consistency. Demoulding before the gate material reaches sufficient glass transition temperature causes matrix gouging and fiber pullout that destroys edge integrity.
Fracture Character
Resin state at the moment of mechanical separation dictates whether the feed passage breaks cleanly or stretches plastically. Achieving an optimal de tooling gate condition prevents micro-cracking from propagating into the structural body of the component. Visual inspection under magnification classifies fracture surfaces into glass-like brittle breaks or ductile shear tearing.
Surface Integrity
Raised scars and recessed pits require secondary grinding operations that add non-value labor to production lines. Inspecting the de tooling gate condition immediately following part removal identifies worn gate inserts or incorrect mold cooling parameters. Smooth gate surfaces reduce post-processing finishing costs and lower defect rates during automated painting operations.
Yield Impact
Part acceptance rates depend on maintaining repeatable edge quality at all resin injection sites. Fluctuations in de tooling gate condition signal underlying drift in barrel temperature or cavity pressure profiles. Catching poor gate separation early prevents sub-surface delamination from reaching final assembly stages.