Technical reference
Mold Texturing Guide
The independent technical reference for surface texturing in plastic injection molding. We document the standards engineers actually specify on drawings, VDI 3400, SPI surface finish and Mold-Tech, together with the draft angle and surface roughness rules that decide whether a textured part releases cleanly from the tool.
What this guide covers
Mold texturing is the controlled surface finish applied to an injection mold cavity, which transfers directly to every molded part. Specifying it correctly affects part appearance, function and, above all, ejection. This guide turns the fragmented standards and supplier charts into a single reference, with the numbers, the methods behind them and the design consequences explained in plain engineering terms.
Texture standards and specifications
The three systems specified across global tooling supply chains, with how they are measured, where they diverge and how to convert between them.
VDI 3400 surface finish
The German standard built on a logarithmic Ra scale, where every six grades doubles the roughness. Grades, Ra values and draft angle guidance.
Read the standard →SPI surface finish
The North American system. Why SPI is a method and an appearance, not only an Ra number, plus steel choice, polymer behavior and common defects.
Read the standard →Mold-Tech textures
The proprietary Standex pattern library, series A to D, and the texture depth rule that drives draft angle. Shrink-away versus shrink-on.
Read the standard →Conversion chart
A practical cross-reference between SPI, VDI 3400 and Mold-Tech, with the honest caveats on where a direct conversion does not hold.
Open the chart →Texture and design
How texture choice changes what a part designer has to allow for, starting with the rule that costs the most money when it is missed.
Draft angle by texture
How much draft each texture depth demands, why deeper textures need more, and the practical degrees-per-texture reference for clean release.
Read the guide →Reference
Need a quick definition? The glossary covers the core terms used across mold texturing, from Ra and EDM finish to shrink-away and orange peel.
Expanding coverage
The reference is built silo by silo. Standards and the first Design pages are live. Coming next:
- ProcessesChemical etching, laser engraving, EDM and how each affects the surface.
- MaterialsHow steel grade and polymer type change the achievable finish.
- TroubleshootingOrange peel, blush, gloss variation and other texture defects.
- Functional texturesGrip, light control and surfaces that do more than look good.