Overview

Cost is the most important factor before selecting any manufacturing process and reducing the costs. Organizations generally opt for large volume production to keep manufacturing costs low. Similarly, for injection molding, the cost per unit would be very high if volumes are low.

Injection molding appears to be more expensive than 3D printing & CNC machining, but the capability to expand production from a few hundred to millions of parts at a faster rate is unmatched with any other process. Establishing the cost of injection molding depends upon multiple factors like design complexity, type of surface finish, material selection etc.

Factors affecting the IM cost

1. Remove undercuts
2. Try not to have unwanted features
3. Core & cavity strategy
4. Minimize aesthetics and finishes
5. Try for self-mating design
6. Avoid post-machining mold changes
7. Use DFM analysis
8. Family molds
9. Multi cavity molds
10. Part size
11. Use overmolding

Avoid undercuts

Avoid undercuts in design because it is the most important factor which affects the tool cost. Undercuts prevent or complicate the part ejection from the mold. If an undercut is needed, then create a design where a slider or side core could be applied. Mold costs could also be reduced by moving parting lines and draft angles enabling easier mold fabrication. Complicated mold designs not only increases the mold manufacturing costs also molded piece cost due to extended cycle time reducing the output.