Dust and drip lip
- Flexible lip wipes the panel face
- IP rating belongs to the assembly test, not the grommet alone
- Panel flatness affects seal line
Molded part guide: grommets
Injection Molded Grommets
A grommet lines a hole so wire or tubing exits without cutting insulation on a sharp panel edge. The flexible lip has to span panel thickness tolerance and still seal, or at least stay put when someone tugs the cable.
Pass-through
The hole in the panel is part of the grommet design
Grommets appear in appliance cords, enclosure cable exits, and automotive firewall pass-throughs. Some are a rubber ring pressed into a hole. Others are overmolded, with a rigid flange and a flexible bore.
The grommet must fit the minimum hole without falling out and not over-compress at maximum hole and maximum panel thickness. That is a tolerance stack on diameter and thickness, not a single nominal.
Strain relief features, such as a ribbed bore or a cable tie landing, belong in the same molded part when the harness is assembled through the panel.
Types
Molded grommet constructions
| Type | Behavior | Tooling |
|---|---|---|
| Single-shot flexible TPE | Whole part elastomeric | Simple mold; may need draft on bore |
| Rigid flange with soft bore | Flange seals to panel; bore grips cable | Overmold the soft bore onto the rigid flange |
| Split grommet design | Wraps cable already terminated | Two halves ultrasonically welded or snapped |
Seal
Dust lip or pressure-tight pass-through
Sealed gland style
- Compression on an O-ring or molded seal lip
- May include a nut or bayonet on the outside
- Higher load on the panel hole edge
Drawing
Grommet quote inputs
Panel hole diameter and thickness tolerance
Cable or tube OD range passing through
Pull force the grommet must survive
Fluids, UV, and temperature at the pass-through
Whether the connector is installed before or after the grommet
IP or drip test target for the full assembly if any
Keep reading
Related guides
Cable clips
Surface routing, not hole linings.
Cable clipsOvermolding
Soft bore on rigid flange.
OvermoldingTPE
Elastomer grommet resin.
TPETPV Santoprene
Flexible seal grades.
TPV SantopreneSensor housings
Cable exit design context.
Sensor housingsEnclosures
Hole layout in shells.
EnclosuresUltrasonic welding vs adhesive
Split grommet joining.
Ultrasonic welding vs adhesiveTolerance stack up
Hole and panel extremes.
Tolerance stack upMolded parts hub
Every part-type guide.
Molded parts hubFAQ
Questions about molded grommets
Can you certify IP rating on the grommet alone?
No. Ingress protection is tested on the full assembly. The grommet is one contributor to the seal path.
Our grommet falls out at minimum hole size.
Increase retention lip interference or add a lock feature. Send hole tolerance and measured panels from production.
Can a grommet be molded onto the cable?
Cable overmolding is a different process than a panel grommet. Send the harness drawing and where the seal must form.
Does TPE need drying before molding?
Hygroscopic grades do. Resin supplier molding guides define dry time and melt temperature for the grade you specify.
Next step
Quote the grommet with panel and cable data
Upload grommet and panel CAD with hole and thickness tolerances. DFM feedback covers lip interference and whether overmolding is needed.