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5-axis CNC milling drawing: Al 7075-T6 block with pockets, toolpath and dimensions
Design Guide · Ribs & Bosses

Ribs & bosses. Sink mark prevention. Stiffening features.

Plastic ribs and bosses design. Stiffening features without sink marks. 60% wall thickness rule, generous fillets, draft for ejection.

Design for manufacturingWuxi, ChinaMOQ 1 partDFM review included

Key principles.

60% wall

Rib 60% of base wall. Prevents sink marks.

3× wall max

Rib height ≤ 3× wall thickness.

2× thread

Boss diameter ≥ 2× thread/insert diameter.

60% wall

Boss thickness 60% of wall to prevent sink.

Stress reduction

Generous base fillets reduce stress concentration.

0.5-1°

Draft for ejection. Per side.

FAQ

Rib thicker than 60% causes sink marks at base. Universal rule.

Center-to-center 3-5× wall thickness. Tighter = stiffer but more material.

OD 2× thread/insert. Wall 60% of base wall. Generous base fillet.

Cross (X) ribs 2-3× stiffness vs parallel. Per loading direction.

Sufficient draft (0.5-1° per side). Generous fillets help.

Rib pattern 2-5× plain plate stiffness. Without weight or sink marks.

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5-axis CNC milling drawing: Al 7075-T6 block with pockets, toolpath and dimensions

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