Mold texture (Mold-Tech, VDI)

Mold texture is a pattern etched, EDM-burned or laser-cut into the mold cavity so every molded part carries a matte, grain or geometric surface. Common callouts are Mold-Tech numbers such as MT-11010 and VDI 3400 grades from Ref 12 (about 0.4 µm Ra) to Ref 45 (about 18 µm Ra). Textures hide sink, flow lines and scratches but need added draft, about 1–1.5° per 0.001 in of depth.

Add it to a part

Applies to: Injection molded thermoplastics and TPEs; urethane casting masters
Adds: 7 days
Cost: Low

Specs

Mold texture (Mold-Tech, VDI) specifications
Texture depth	About 0.0004–0.006 in (10–150 µm) typical
Added draft	About 1–1.5° per 0.001 in (25 µm) of depth, on top of base draft
VDI 3400 range	Ref 12 (Ra 0.4 µm) to Ref 45 (Ra 18 µm)
Methods	Chemical etch, EDM, laser texturing
Hides	Sink, flow lines, knit lines, scratches and fingerprints
Lead time	Often 1–2 weeks at a texture house

Call out on the drawing

Mold-Tech texture numbers (e.g., MT-11010, MT-11020)
VDI 3400 Ref 12–45 (EDM texture scale)
SPI D-1 to D-3 (blasted matte)

Materials it suits

Common on

Questions

How much draft does a textured surface need?

Add about 1–1.5° per 0.001 in (25 µm) of texture depth to the base draft. A light texture may need 1.5–3° total; deep leather grains need 5° or more. The texture house specifies minimum draft for each pattern.

What is VDI 3400?

VDI 3400 is a German scale for EDM surface textures. The number maps to roughness: Ref 12 is about 0.4 µm Ra, Ref 24 about 1.6 µm, Ref 30 about 3.2 µm and Ref 45 about 18 µm. It is widely used for matte industrial finishes.

Can a texture be added after the mold is built?

Yes. Texturing is usually the last step of tool build and can be added or changed later, as long as the walls have enough draft. Retexturing worn or changed surfaces is routine.