Injection Molding Design Guide
Smart Design = Lower Costs + Better Parts
At Taurus Engineering, we help you move from concept to production efficiently—with guidance that balances performance, manufacturability, and cost. Below are our top design recommendations to get the most out of your mold and part.
Core Design Tips
- Uniform Wall Thickness
• Aim for consistent wall thickness to avoid sink marks and warping.
• Recommended range: 0.0625″ to 0.125″ Common target: ~0.09375″ - Add Draft to Vertical Walls
• Draft makes ejection easier and reduces wear on tooling.
• General rule: 1° per side for smooth surfaces, 1.5–2° for textured areas. - Avoid Undercuts
• They complicate mold design and drive-up tooling costs.
• Use clever parting lines or design features to eliminate them where possible. - Keep Parting Lines Simple
• Flat or minimal variation = more affordable molds. - Mind the Corners
• Match inside and outside radii to prevent inconsistent wall thickness.
• Avoid sharp corners that trap gas—add small fillets instead.
Special Considerations
Thin Walls
- Walls under 0.050" may be hard to fill, depending on material and geometry.
- Local areas can go as low as 0.015" if isolated and small.
Thick Walls
- Over 0.100" Expect longer cooling times = higher part cost.
Deep Cavities
- Deeper than 2.5" can require custom mold bases, increasing tooling cost.
Lettering & Text
- Keep it shallow: the depth should be less than 2× the stroke width to ensure full fill.
Pointed or Sharp Features
- These can be hard to mold cleanly. Soften or round them for best results.
Ejection Matters
- Most economical: ejector pins
- More costly: blade ejectors, sleeves, or stripper plates
Start Smarter with Taurus
Design for manufacturability starts before the mold is built. Our engineering team is here to guide you every step from DFM reviews to mold design, material selection, and part optimization.