Injection Mould Cavity Surface Roughness Measurement Using Silicon Replicas
Indirect silicone replica metrology resolves deep mould cavity roughness parameters non-destructively within five percent variance of direct steel scans.
Maximum Height Profile
Meaning
Vertical distances between the highest peak and the lowest valley within a defined sampling length provide a measure of the extreme surface irregularities on a moulded part. This maximum height profile is often denoted as Rz in metrology reports and assists in identifying individual flaws that an average value might hide. It is particularly useful for assessing surfaces that must seal against a gasket or provide a specific tactile feel.
Roughness Evaluation
Measurements are taken across a representative section of the tool or the plastic component. While the average roughness describes the general texture, the maximum height profile captures the most severe scratches or pits.
Release Resistance
High peaks in the tool surface can act as mechanical anchors that resist the ejection of the plastic part. If the maximum height profile is too high, the friction during the ejection stroke increases. This leads to drag marks or stressed areas on the part surface.
Proper polishing reduces these peaks to ensure a smooth release. Controlled peak height minimizes the risk of cosmetic damage during the ejection cycle.
Coating Integrity
Functional coatings like chrome or ceramic layers depend on a controlled base texture for adhesion. An excessive maximum height profile can cause the coating to bridge over valleys or leave peaks exposed. This uneven coverage leads to premature wear or localized corrosion of the underlying tool steel.