Contract manufacturing value often peaks after the press opens — when parts move through injection molding secondary operations, assembly, and packaging as finished sub-systems. OEMs that treat the molder as “parts only” duplicate handling, inventory, and quality loops at their own plant.
Common secondary operations in plastic contract manufacturing
- Deflash and gate trim — cosmetic Class A cleanup
- Ultrasonic or vibration weld — enclosure halves, filter assemblies
- Heat stake and inserts — brass, helicoil, PEM hardware
- Pad print / laser mark — logos, serials, regulatory labels
- Leak test — sealed housings for IP-rated products
- CNC post-machining — tight bores after molding when needed
Assembly and kitting levels
| Level | Deliverable | OEM benefit |
|---|---|---|
| Component | Single molded part, inspected | Simple BOM, you assemble |
| Sub-assembly | Part + inserts + hardware | Shorter line time |
| Module | Multiple molded parts + purchased items | Drop-in to final product |
| Packaged SKU | Retail-ready (less common in industrial OEM) | Outbound logistics simplified |
Why integrate secondary ops at the molder
- One quality record from mold to ship state
- Less freight between molding and assembly sites
- Engineering feedback loop on snap fit, weld, and insert issues
- Lower total labor when country cost structure favors integrated shop
Specify secondary ops in the RFQ
Do not assume “included.” Attach insert drawings, torque specs, weld strength requirements, and cosmetic acceptance photos. Deuchi’s contract manufacturing scope covers secondary processing and assembly — quote line items separately for transparency.
Quality checkpoints
- Incoming resin and insert lot control
- In-process checks after each secondary op
- Final dimensional and functional test on ship state
FAQ
Can you source purchased hardware?
Many contract manufacturers kit OEM-specified hardware; clarify commercial terms and substitute approval.
What about cleanroom or ESD needs?
Define environment class in RFQ — not all shops are certified for medical cleanroom without audit.
Do secondary ops affect mold design?
Yes — insert bosses, weld joint geometry, and pad print flats should be designed in DFM, not added after T1.
Next step: Describe your target ship state for a scoped quote.