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.
Cavity Steel
Meaning
High-strength metal alloys provide the structural foundation and wear resistance required for the primary forming surfaces within an injection mould. Choosing the correct cavity steel requires a trade off between hardness, thermal conductivity, corrosion resistance and machinability. These materials must withstand millions of cycles under high pressure and temperature without deforming or cracking.
Alloy Durability
Pre-hardened steels like P20 are common for large moulds because they do not require further heat treatment after machining. Through-hardened steels such as H13 offer superior resistance to abrasive resins like glass-filled nylon. This durability is necessary for high-volume tools.
Thermal Performance
Heat removal determines the overall cycle time and the cooling rate of the polymer. Steels with higher thermal conductivity allow the moulder to reach the ejection temperature faster. This efficiency reduces the cost per part in high-volume production.
Proper cooling prevents defects such as sink marks or warping in thick-walled sections. Cooling speed varies by alloy.
Surface Refinement
The ability of the material to take a high polish affects the aesthetic quality of the part. Vacuum-melted alloys are often specified for optical components because they contain fewer inclusions that could mar the finish. These premium grades allow for the mirror finishes necessary for transparent lenses or high-gloss housings.
Surface quality is maintained.