1. Compound selection
A foam gasket starts as a compound decision, not a shape decision. Cell structure, density and the cure system are set here, and they determine compression set, the closing force the lid has to deliver, and how the material behaves after a thermal event. Changing any of these later means changing the part, not the process.
2. Extrusion and cell structure
Foam profiles are extruded with a blowing agent that forms the cell structure as the material cures. Control at this step is what separates a gasket that closes evenly from one that has dense and soft patches along its length. Even cell structure is the reason a low closing force can still hold an ingress rating.
3. Curing
Curing sets the final elasticity. Under-cured material continues to change dimension after it leaves the line, which shows up as a lid that was tight at assembly and loose after a season. Cure state is checked before the profile is cut, not after it is packed.
4. Cutting, corners and bonding
A pack gasket is a frame, not a length. Corners are mitred and bonded so the joint closes rather than folding and leaving a gap. Adhesive backing is applied where the part has to stay in place while the lid is fitted. Doing these in-house keeps the tolerance from drifting at the last step.
5. Inspection before packing
Density, hardness, dimensions and appearance are checked before goods are packed, and the record travels with the batch. For a pack gasket this matters more than usual - the part is assembled once and is expensive to reach again.
Sampling before you commit
Send the groove drawing and the closing force your lid can deliver. We will run a sample so you can test compression and ingress on the actual enclosure rather than trusting a datasheet.
Profiles for this application
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Working on something like this?
Send the drawing, cross-section, operating temperature and what the seal has to resist. We will tell you whether a stock profile fits or the part needs extruding, and quote both.