Vendor bore and depth
Match the insert vendor spec. Do not invent a bore on this page.
Post-mold inserts
Post-Mold Inserts in Injection Molding: Install After the Shot
Install the insert after the shot. Size the boss to the vendor bore, keep cosmetics off cavity shutoff, and call out insert installation on the RFQ.
Design guideline
Install the insert after the shot
A post-mold insert is installed after the part is molded: heat-set, ultrasonic, or press-in. The mold does not shut off on the insert.
Size the boss bore and depth to the insert vendor spec. Cosmetic faces stay cleaner when metal never sees cavity shutoff. Insert installation is a scoped secondary operation when the RFQ calls it out. DFM review checks the boss, resin, and insert type.
This spoke owns after-the-shot inserts. Molded-in inserts load the tool during fill. Bosses own the post. Self-tapping screw bosses skip the insert. The design guide hub lists every topic.
Roles
Which page answers which insert question
Stay here for after-the-shot inserts. Open a sibling for in-cavity inserts or the post.
| Page | Use it for |
|---|---|
| Post-mold inserts (this page) | Heat-set, ultrasonic, or press-in after molding |
| Molded-in inserts | Inserts loaded in the cavity during fill |
| Boss design | The post the insert sits in |
| Self-tapping screw bosses | No insert; the screw cuts plastic |
| Insert retention | How the insert stays put in service |
| Wall thickness | Nominal wall the boss should reference |
| DFM review | CAD check before steel and secondary ops |
Checks
What DFM review looks for on post-mold inserts
Qualitative checks. No figure on this page is a NetProto specification.
Boss support
A free-standing boss can crack when the insert is driven. Tie it back.
Cosmetic shutoff
Keeping metal out of the cavity avoids insert shutoff witness.
Secondary scope
Call out insert installation on the RFQ if NetProto should run it.
Decision
Post-mold install versus loading the insert in the tool
Wrong: assume every insert is molded in. Right: pick after-the-shot when shutoff and handling fit the program.
What goes wrong
- Leave the boss unsized for the vendor insert
- Assume insert installation happens with no RFQ note
- Treat a heat-set insert like a molded-in knurl
What to try first
- Size the boss to the vendor bore and depth
- Call out heat-set, ultrasonic, or press-in on the RFQ
- Open molded-in inserts if the metal must be in the shot
RFQ
Send these notes with CAD for a post-mold insert review
The quote can start from CAD alone. These notes make the DFM pass specific.
Insert type and vendor, if known
Boss OD, bore, and depth callouts
Heat-set, ultrasonic, or press-in method
Whether insert installation is in program scope
Cosmetic faces that cannot show sink or witness
How the boss ties into the wall or a gusset
Related
Related design guidelines
Stay on this spoke for its question. Open a sibling for the neighbor topic or the CAD check.
Insert molding
The capability page when metal is in the shot.
Insert moldingSecondary operations
Insert installation when scoped on the RFQ.
Secondary operationsDFM review
How NetProto checks the boss and insert plan.
DFM reviewFAQ
Post-mold inserts FAQ
What is a post-mold insert?
It is a metal insert installed after the part is molded. Heat-set, ultrasonic, and press-in are common methods. The mold does not shut off on the insert.
Does NetProto install post-mold inserts?
Insert installation is a scoped secondary operation when the RFQ calls it out. Name the insert type and count so the quote can include that work.
Can post-mold inserts migrate in service?
Yes if the boss is thin, the bore is wrong, or the resin creeps. Follow the vendor bore and support the boss. The retention page owns pull-out.
When should I use a post-mold insert instead of molding it in?
When you want to avoid cavity shutoff on metal, or the insert count is better handled after the shot. Molded-in inserts own the in-cavity path.
Do I still need a proper boss?
Yes. The insert does not replace boss design. Core the post, add draft, and tie it back so install does not crack the wall.
How is this page different from molded-in inserts or self-tapping bosses?
This spoke owns after-the-shot inserts. Molded-in inserts load the tool. Self-tapping bosses skip metal. DFM review checks your CAD.
Next step
Upload CAD for DFM review of post-mold inserts
Share boss geometry, insert type, and whether installation is in scope so review can check the bore, support, and cosmetics before quoting.