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Glossary

What Is VDI 3400? Injection Molding Explained

VDI 3400 is a European numbering system for mold texture depth and appearance.

Glossary

VDI 3400 numbers describe European mold texture depth and appearance

Drawings may use VDI instead of SPI or MoldTech when supply chains expect it.

Higher VDI numbers mean coarser texture and usually require more draft on sidewalls.

VDI and SPI solve similar problems with different numbering systems.

Mixed standard drawings need explicit mapping or one primary standard per face.

Glossary

How vdi 3400 shows up on real programs

Library photos illustrate molding and tooling context for this term.

  • Use the term in RFQs with geometry and material context, not in isolation.
  • Link to the design guide when the term affects steel or part design.
  • Upload CAD when the term changes tooling scope or piece price.
Engineer reviewing injection molding terminology on a part drawing

Standards

Finish vocabulary buyers mix

Clarify which standard controls acceptance.

StandardTypical use
SPI bandsPolish and blast gloss or matte on mold steel
MoldTech MT numbersEtched grain from plaques
VDI 3400Numeric texture depth common in EU tooling packs

Go deeper

Where this term connects

Each link is a different angle on the same program, not a duplicate definition.

Visual reference

Photos from molding and tooling programs

Images are selected from the NetProto Forge media library for this topic.

Injection molded production parts on a tray

Injection molded production parts on a tray

Injection molded production parts on a tray

Engineer reviewing a molded part drawing

Engineer reviewing a molded part drawing

Engineer reviewing a molded part drawing

Plastic housing components from a steel tool

Plastic housing components from a steel tool

Plastic housing components from a steel tool

FAQ

VDI 3400 questions

Can VDI and SPI appear on one drawing?

Use one primary standard per face or map equivalents in the mold spec.

Does higher VDI always mean cheaper tooling?

Not always. Etch depth and draft drive cost and risk.

How do I pick a VDI number?

Start from a physical sample or spoke guidance, then lock on T0 texture samples.

Next step

Align texture standard early

Upload CAD noting VDI, SPI, or MoldTech per face.