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.
Vmc
Meaning
Functional void volume metrics determine the fluid retention capacity enclosed within the core zone of a surface topography. Precision mould designers specify Vmc to quantify lubricant storage volume between ten percent and eighty percent material ratio levels on sliding tool components. High core void volume values ensure sustained grease retention along guiding pin surfaces during high cycle production runs.
Datasheet surface roughness average Ra cannot quantify this localized fluid containment volume.
Core Geometry
Mathematical integration of the areal material ratio curve calculates core void space separate from peak and valley structures. The calculation excludes upper surface peaks to isolate the intermediate zone where sliding lubricants reside. Laser textured mould inserts provide defined micro-cavity volumes that maintain oil film integrity.
Resin molders select surface textures based on functional fluid volume requirements.
Tribological Performance
Core void retention prevents dry metal contact and severe scoring on mould slides and ejector mechanisms. Adequate void space traps particulate wear debris away from primary sliding interfaces. Regrind resin processing introduces abrasive dust that packs into core voids, diminishing effective fluid storage.
Periodic mold washing restores open core void volume to prevent premature mechanical binding.
Measurement Protocol
Optical profilometers calculate volumetric parameters from calibrated three-dimensional surface datasets. Inappropriate filter settings alter material ratio slope curves and distort reported void volume values. Quality standards require strict adherence to standard cut-off limits during surface certification.
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.