Tool Steel Selection Guidelines for High Volume Injection Moulding Tooling Baseline Fabrication
High-volume injection moulding baseline tooling demands martensitic stainless or pre-hardened steels matched to polymer abrasiveness and cycle volume.
Rockwell Hardness
Meaning
Mechanical resistance to indentation provides a standardized measure of the hardness of a material. The rockwell hardness test determines the depth of penetration of a diamond cone or a steel ball under a specific load. It is the primary metric used to specify the durability of mould steels and ejector components.
Hardness Scale
selection depends on the expected properties of the material being tested. The HRC scale is used for hardened tool steels, while the HRB scale is applied to softer alloys or non-ferrous metals. Correct scale selection ensures the data is comparable across the supply chain.
Material Suitability
is assessed by comparing the measured hardness against the requirements of the resin being processed. A tool that is too soft will suffer from rapid wear and deformation under injection pressure. Conversely, a tool that is too hard may be susceptible to brittle fracture.
Finding the correct hardness level is a balance between wear life and structural safety.
Quality Control
involves testing the steel after heat treatment to verify it meets the datasheet values. Inconsistent hardness across a tool face can lead to uneven wear and part failure. Regular testing ensures that every component in the mould assembly performs as intended.