Optical Profilometry Parameter Verification for Hardened Steel Tool Cavities
Verify hardened steel tool cavity topography using ISO 25178 areal parameters and filtered coherence scanning interferometry to guarantee polymer part release.
Vmp
Meaning
Functional peak material volume metrics calculate the solid material volume contained within the upper ten percent of a surface height distribution. Moulding engineers utilize Vmp to assess the initial wear volume of micro-peaks on newly machined cavity inserts and textured plastic parts. High initial peak material volume indicates prominent asperities that abrade rapidly during initial moulding cycles.
Datasheet average roughness Ra does not isolate this vulnerable upper material zone.
Peak Analysis
Cumulative material ratio curve integration computes solid peak volume above the ten percent material ratio threshold. High peak volume values correlate with prominent surface asperities that experience intense localized contact pressure. Precision machining strategies minimize peak material volume to yield stable bearing surfaces.
Polymer demoulding forces drop as sharp peak asperities wear down during initial tool break-in.
Tool Wear
Mechanical friction flattens high peak volume asperities during repetitive injection moulding cycles. Rapid peak material loss alters part surface appearance and creates micro-particulate contamination inside tool cavities. Abrasive glass fiber fillers accelerate peak erosion on un-coated tool steel inserts.
Surface treatments like nitriding increase peak shear resistance to preserve original texture dimensions.
Specification Limit
Metrology reports monitor peak volume reduction to quantify tool wear progression over production campaigns. Excess peak volume on textured plastic parts increases tactile harshness and scuff susceptibility. Quality control defines maximum peak volume thresholds to ensure consistent part feel across production shifts.
Standard ISO 25178 Parameters for Optical Profilometry Inspection
ISO 25178 areal optical profilometry replaces subjective 2D stylus traces with quantitative 3D parameters that accurately govern tool wear and part demoulding.