Die casting (typical)
- Metal strength, stiffness, and heat resistance
- Machining, trimming, and coating steps are common
- Heavier parts and corrosion protection to plan
Process comparison
Injection Molding vs Die Casting: Metal Castings vs Molded Plastic
Die casting forces molten metal into a steel die. Injection molding does the same with plastic, which can cut weight and finishing steps when the part allows it.
Material and process choice
Metal casting versus plastic conversion
The question is usually whether the part must stay metal.
Die casting injects molten metal such as aluminum, zinc, or magnesium into a steel die. It suits parts that need metal strength, heat resistance, or electrical conductivity.
NetProto does not offer die casting. This guide helps decide when a cast part can move to an engineering plastic and be quoted as a molded part.
Side by side
How the processes differ
Material requirements decide more than the tooling does.
Injection molding (NetProto)
- Lower weight with engineering or filled resins
- Color, texture, and snap features molded in
- Several cast and machined parts can merge into one molded part
Routing table
When a cast part may move to plastic
Qualitative only. Confirm loads and temperatures in DFM review.
| Signal | Stay with die casting | Evaluate molding |
|---|---|---|
| Load | High structural load or impact | Moderate load met by filled resin |
| Heat | Sustained high temperature | Within engineering resin limits |
| Shielding | Metal enclosure required for EMI | Shielding compound or coating acceptable |
| Finishing | Machined surfaces are acceptable | Molded finish and color preferred |
Conversion readiness
Metal to plastic checklist
Confirm these before you quote a steel tool.
Load, temperature, and chemical exposure in service
Candidate resin from the materials library, often glass filled
Thick sections redesigned for molding rather than copied from the casting
Fasteners or inserts that replace tapped metal threads
Continue exploring
Related guides
Process first, then resin.
Compare hub
All comparison guides.
Compare hubInjection molding vs RIM
Reacting polyurethane versus thermoplastic molding.
Injection molding vs RIMInjection molding vs thermoforming
Sheet formed parts versus fully molded geometry.
Injection molding vs thermoformingGlass filled nylon
A common resin for metal replacement parts.
Glass filled nylonMetal to plastic conversion
Redesign rules when a cast part moves to plastic.
Metal to plastic conversionFAQ
Common questions
Can I copy the cast part geometry into a mold?
Rarely. Castings often have thick sections that sink or warp in plastic. DFM review reshapes walls and adds ribs for the molded version.
Does NetProto quote die casting?
No. NetProto quotes injection molding with hardened steel tooling only.
Next step
Quote the plastic version of the part
Upload CAD for steel tool and piece price together. NetProto manufacturing is ISO 9001 certified.