Extrusion (typical)
- Continuous profiles cut to any length
- Lower die investment than a molding tool
- No features that change along the length without secondary work
Process comparison
Injection Molding vs Extrusion: Constant Profiles vs Three-Dimensional Parts
Extrusion pushes resin through a die to make a continuous profile. Injection molding fills a closed tool, so features can change in every direction.
Process choice
One cross section forever versus full 3D geometry
Many products use both: an extruded length with molded end caps or connectors.
Extrusion forces melted resin through a shaped die and cuts the continuous output to length. Tubing, seals, channels, and trim all keep the same cross section along their length.
NetProto does not offer extrusion. Injection molding is the route for end caps, connectors, clips, and any part whose shape changes along its length.
Side by side
What each process shapes well
Cross section versus geometry.
Injection molding (NetProto)
- Features in every direction in one shot
- Snap fits, bosses, and threads molded in
- Mates to extruded profiles as caps and connectors
Routing table
Which process fits the part
Qualitative only.
| Part | Extrusion tends to fit | Injection molding tends to fit |
|---|---|---|
| Tubing and channels | Constant cross section | Not practical |
| End caps and plugs | Not practical | Closed shape with fit features |
| Connectors and clips | Rarely | Snap fits and locating features |
| Profiles with holes or tabs | Extrude, then machine or punch | Mold in one shot if length allows |
Quote inputs
Send this with the molded part CAD
Molded parts that mate to extrusions need the profile data.
Profile drawing and its tolerance at the mating end
Profile resin, so the molded part can match or bond
How the cap or connector is retained: press fit, snap, or weld
Annual volume for each profile size
Continue exploring
Related guides
Process first, then resin.
Compare hub
All comparison guides.
Compare hubInjection molding vs die casting
Metal castings versus molded plastic conversion.
Injection molding vs die castingInjection molding vs RIM
Reacting polyurethane versus thermoplastic molding.
Injection molding vs RIMDesign for manufacturing
DFM review before steel is cut.
Design for manufacturingFAQ
Common questions
Can a long part be injection molded instead of extruded?
Sometimes, if it fits the press and the shape changes along its length. Long constant profiles almost always stay extruded.
Does NetProto quote extruded profiles?
No. NetProto quotes the injection molded parts that attach to them.
Next step
Quote the molded parts that finish the profile
Upload CAD for steel tool and piece price together. NetProto manufacturing is ISO 9001 certified.