1. How much force can the closure deliver?
This comes first because it decides solid versus sponge. A hand-operated lid delivers very little, which points to sponge. A bolted flange can compress a solid profile. Specifying solid where there is no force to close it is the most common specification error.
2. What temperature range in service?
Not the peak, the range - including what it sees when the machine is off, and during cleaning or sterilisation. Compression set has to be quoted at service temperature, not at room temperature.
3. What does it touch?
Fluid, gas, food product, cleaning agent. Cleaning agents are the usual surprise - a seal that handles the product can be destroyed by what it is washed with.
4. Solid, sponge, or hollow?
Solid for high compression load and wear. Sponge for low closing force and uneven surfaces. Hollow where you need large deflection with modest force. Each has a place and the choice follows from question 1.
5. What shape is the groove?
Groove depth and width set the cord diameter and the compression. Irregular grooves, corners and varying gap are the case for a custom cross-section rather than a catalogue shape.
6. What documentation do you need?
Material declarations, compliance statements and inspection records - ask for the grade you are buying, not the grade on the brochure. Getting this in the first enquiry avoids a second round when your quality team asks.
Send these six and we can quote
Closing force, temperature range, media, solid or sponge, groove drawing, documentation needed. That is enough for a quotation and a sampling plan.
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.