DFM for injection molds

DFM (Design for Manufacturability) reviews plastic part geometry so it can be molded cleanly. When a STEP arrives we scan wall thickness, draft, undercuts and knit lines; critical notes are reported once.

Uneven walls cause sink, warp and dim drift. Thin zones freeze early; thick zones leave residual stress. Evening walls or softening transitions improves both tool and part quality.

Draft is required for ejection. Weak draft on vertical faces causes drag and high ejector force. Side-actions are flagged early so mechanisms fit the tool design.

Cooling layout drives cycle time and stability. Gate location, flow balance and air traps are clarified in DFM notes before hot or cold runner selection.

DFM checklist

• Min / max wall and transition radii
• Draft angles (inner / outer)
• Undercut, slide and lifter needs
• Gate type, location and balance
• Cooling layout and cycle target
• Ejector points and witness risk
• Resin choice (shrink, glass fill)