Tooling Surface Polish Impact on First Article Inspection Accuracy
Uncalibrated optical scans on mirror-polished plastic introduce up to fifteen micrometers of false elevations, ruining First Article Inspection accuracy.
Anti Glare Spray
Meaning
Chemical compound suspension applied to optical inserts or cavity surfaces during polymer transformation to suppress specular reflections through diffuse scattering. Liquid carriers deposit microscopic diffusing agents onto the mould wall or the finished polycarbonate lens before secondary curing takes place. Tooling temperature gradients dictate whether the deposited particulate forms an even matte finish or aggregates into random clusters.
Resin Property Control
Polycarbonate and polymethyl methacrylate components demand tight control over surface gloss to eliminate operator eye fatigue during inspection tasks. Anti glare spray modifies the boundary layer friction coefficient during the high pressure injection phase. Viscosity variations in the carrier solvent change the dispersion angle of the particulate across complex curved geometries.
Virgin feedstock requires uniform additive coverage to prevent localized sink marks adjacent to gate locations. Regrind batches introduce unpredictable melt flow indices that override standard coating thicknesses unless the application pressure doubles.
Moulding Process Variable
Cavity surface temperature acts as the primary driver for solvent evaporation rates during the pre injection dwell cycle. Injection speed determines whether the suspended micro beads anchor securely into the solidifying polymer skin or detach into the runner system. Clamping tonnage fluctuations crush the delicate topographical peaks formed by the dried suspension, resulting in glossy hot spots on the molded article.
Part specifications govern the allowable haze percentage across the optical aperture, whereas material specifications dictate the chemical compatibility between the propellant and the base resin. Datasheet values for melt flow rate rarely reflect the actual shear thinning behavior observed inside a textured production tool.
Tooling Surface Defect
Excessive film thickness creates orange peel textures and structural weakness along weld lines in thin walled enclosures. Vapour entrapment causes microscopic craters that destroy the light transmission properties of transparent safety visors. Part rejection rates climb sharply when the particulate concentration exceeds the saturation threshold of the solvent carrier.
Thermal degradation of the residual polymeric binder leaves carbonaceous deposits inside the micro grooves of the mould wall.