Meaning
Quality control evaluation of mold cavities produced by electrical discharge machining ensures that the tooling conforms to dimensional tolerances and surface finish specifications before injection moulding begins. Through sinker edm inspection, engineers assess the cavity dimensions, electrode wear patterns, and surface roughness profiles. This inspection process is restricted to cavities machined using die-sinking equipment and is conducted prior to polishing or texturing.
Its primary role is to detect machining errors that would be replicated on the molded polymer parts.
Cavity Dimension
Coordinate measuring machines and optical profilers verify the geometry of the machined cavity. This phase of sinker edm inspection measures the depth and corner radii of the mold features. Ensuring high dimensional accuracy prevents subsequent part defects.
Tooling Finish
Machining parameters can leave a textured finish that can act as a mechanical interlock, making part ejection difficult. High-quality sinker edm inspection detects these rough surface regions so they can be polished or textured appropriately. This verification reduces the risk of part sticking or pin push-through during the demoulding step.
Polishing the cavity is necessary to ensure the polymer flows smoothly without excessive shear.
Moulding Performance
Proper inspection of the machined cavity guarantees that the plastic melt will fill the tool without encountering unexpected flow restrictions. When sinker edm inspection is bypassed, microscopic tool defects can cause localized shear stress and molded-in stress in the polymer part. This stress leads to warpage and dimensional instability after the part cools.
Preventing these moulding issues requires systematic inspection of every machined cavity.
