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Design Guide · Draft Angle

Draft angles.
Mold release.
Released parts.

Draft angle reference for injection molding, casting, forging. 1-2° standard. Insufficient draft causes ejection issues, parts stuck in mold.

01 · Key principles

Key principles.

Injection molding

1-2° standard

1° minimum for smooth parts. 2-5° for textured. Higher for deep features.

Casting

3-5° typical

Sand cast 3-5°. Investment cast 1-3°. Per process.

Forging

7° typical

Heavy draft for forging. Material flows through dies.

Vertical surfaces

Always draft

Even small draft (0.5°) on tall vertical surfaces.

Internal features

Cores need draft

Internal pockets, ribs, bosses need draft for ejection.

Texture impact

Add 1-2°

Textured surfaces need additional draft per texture depth.

FAQ

Why is draft angle important?

Without draft, part won't release from mold. Parts stuck cause damage to mold and parts.

How much draft?

1-2° standard injection. 3-5° for textured. 0.5-1° absolute minimum smooth parts.

No-draft option?

Some processes (CNC, 3D printing) don't require draft. Specify if molding required.

Internal pocket draft?

Same as external draft. Side actions or inserts may avoid draft requirement.

Specifying on drawing?

Note "1° draft per side" or specific angle per feature. CAD models include draft directly.

Cost impact?

No draft = need EDM mold inserts. Adds 30-100% to mold cost. Specify draft up front.

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