Sealing A Connector And Moulding Strain Relief In One Operation
Hot melts are used for sealing the plug and also for cable strain relief. Doing both in one low pressure shot removes a whole assembly step.
What The Assembly Has To Survive
A cable assembly needs the plug sealed against moisture and the cable supported where it exits, so the conductors are not loaded at the solder joint. Traditionally that is a moulded boot plus a sealing operation, or a slipped-on grommet.
Why The Obvious Approach Fails
- Slipping a grommet on is time-consuming and can cause repetitive strain injury
- A separate boot and seal means two parts and two operations
- Cable pull-out loads the solder joints rather than the housing
- Sealing compounds that cure slowly hold up the line
Grade Selection And Why
Low pressure moulding with polyamide hot melt resin. The moulded body seals the plug and forms the strain relief in the same shot, and the grommet can be injection moulded in place rather than slipped on.
How The Job Runs
Step 01
Select the resin against the housing material — polyamide for PA 6.6, ABS and PVC, polyolefin for PP, PE and PET
Step 02
Position the terminated connector and cable in the mould
Step 03
Mould at low pressure over the plug and the cable exit
Step 04
Cool and demould with the strain relief already formed
Step 05
Pull test the cable exit as part of the release criteria
Quality Control
Pull-out force at the cable exit, seal integrity at the plug face, and adhesion to the connector housing material. The moulding can also include the strain relief, which improves the appearance of the finished assembly.
Result
The grommet step disappears, the seal and the strain relief become one feature, and the assembly leaves the mould ready to handle.
Customer Benefit
One operation instead of three, with the ergonomic problem of fitting grommets by hand removed from the line.
Products In This Application Note
Hot Melt Resin
Black Polyamide Hot Melt Resin UA-G182C
Black polyamide resin for low pressure moulding of automotive and electronic assemblies
View Grade Data
Hot Melt Resin
Polyamide Hot Melt Adhesive Resin UA-G0175
High viscosity polyamide resin for low pressure moulding and filter bonding
View Grade DataQuestions About This Application Note
Is this a named customer project
No. This is an application reference built from the published process data for the grades named on this page. It describes a typical setup rather than a specific customer project, so treat the parameters as a starting point for your own trial.
Can you supply these grades for a trial
Yes. Sample requests are handled by email — state your substrates and process temperature limits.
Will the same parameters work on my line
Treat them as a starting point. Press condition, substrate and geometry all shift the window, which is why a trial comes before a production order.
Which grade should I start with
The products listed on this page are the ones this application uses. If none fits, tell us the joint and we will look wider.
Have A Similar Joint To Solve
Send the substrates, the service temperature and the process limits of your line. We will say which grade to trial and what to watch for.