Volumetric Areal Parameter Thresholds for Predicting Gate Wash Degradation
Volumetric areal parameters predict gate wear before profile roughness detects steel loss, preventing tool failure in glass-filled polymer injection molding.
Micro-Trenching
Meaning
Formation of unwanted narrow grooves on a surface during a manufacturing or molding process constitutes a specific type of topographic defect. Micro-trenching often appears during the etching of silicon or the abrasive wear of mold surfaces used for precision optics. It results from the concentration of energy or particles at the base of a feature sidewall.
Erosion Mechanism
High-velocity particles or ions reflect off the vertical walls of a structure. These reflections focus the energy at the junction between the wall and the floor, carving a deep furrow. In injection molding, this occurs when glass fibers in the resin stream are funneled through a narrow gate and strike the opposite cavity wall.
Part Failure
Stress concentration in these narrow grooves leads to premature cracking. If the trench occurs in a high-stress area of the part, it acts as a notch that reduces the impact strength of the final product. Surface finish requirements are often compromised by the presence of these irregular lines.
Tool Surface
Cavity longevity decreases when erosion patterns develop. Frequent polishing becomes necessary to remove the grooves and restore the surface. This maintenance increases the cost per part over the life of the project.