O-ring compression
Catalogue O-rings cover most needs. When yours falls outside them — an odd size, a special compound, a colour for identification —…
Open this variantVolume route · solid silicone and rubber
Compression moulding.
Solid silicone or rubber pre-formed, loaded into a heated steel tool, and pressed under cure. Sensible tooling cost, thousands of parts per tool, and the workhorse route for volumes that don't yet justify LSR.
The workhorse
The route that fits most of what we make.
Most of the rubber and silicone parts in the world are made this way. A pre-formed slug of material is placed into a heated steel tool, the press closes, the material flows to fill the cavities, and cure completes under pressure and heat. Simple, repeatable, and forgiving.
Compared with LSR injection, tooling costs a fraction — often a tenth. Cycle times are longer and there's flash to deal with, so the unit cost above a certain annual volume tips in LSR's favour. But below that point, compression wins on total cost every time.
It's also the route we use for materials LSR can't handle: EPDM, nitrile, natural rubber, high-durometer silicones, and any grade that's supplied as a solid gum. Almost anything in the rubber family can be pressed.
For most first tools — where you're still learning what the part wants to do at volume — compression is where we start. If demand later justifies it, we can convert the design to LSR without having thrown away the earlier tooling investment.
Drill down
3 ways we run compression moulding.
Each variant has its own page with the specifics: where it fits, how we run it and what to send us.
Medical compression
Not every medical part needs an LSR injection tool. For early device builds, low-volume products and larger components, compression…
Open this variantIndustrial compression
Pads, buffers, bellows, grommets and seals for machines that have to keep running. Industrial compression work is about the right compound…
Open this variantWhy buyers choose it
Three reasons compression usually wins first.
Tooling cost you can commit to
A compression tool for a modest part is a fraction of an LSR tool. That means the numbers work at annual volumes where LSR would be a very expensive mistake.
Any material the family supports
Silicone in high durometers, EPDM, nitrile, natural rubber — all press well. LSR only injects one material family. Compression opens the whole rubber shelf.
Forgiving of design changes
A steel compression tool can be reworked more freely than an injection tool. If the design still has iterations left in it, compression tolerates that better.
How it runs
Load, close, cure, release.
The process itself is straightforward. The craft is in the tool design, the material charge, and where the flash lands.
Charge preparation
The material is milled to the right consistency and cut to weight for the shot. A slightly overweight charge is deliberate — it guarantees fill and forces the excess into a defined flash groove.
Load into the tool
The operator (or a robot, on higher-volume cells) places the charge into the cavity, on top of any inserts if the job is an insert-moulded part.
Press closes and cures
The press closes under specified pressure. The heated platens transfer heat into the tool; the material flows to fill the cavity; cure completes within the specified time.
Press opens, part released
The press opens and the parts are lifted from the cavities. On many tools, this happens by hand; on higher-volume cells, ejector pins or a stripper plate release the parts.
Deflash and inspection
Excess material is trimmed off — by hand for short runs, or through a cryogenic tumble for higher volumes. First-off parts are checked against the approved sample.
To quote it
What we need to price a compression job.
The part and its material
A drawing or a sample and a nominated grade. We'll flag any features that will be awkward in compression before you commit.
The annual volume
This sets cavity count. A one-cavity tool is fine for a few thousand a year; a twelve-cavity tool is what you want above 50,000.
Post-process needs
Whether the part needs bonding, printing, secondary trim or assembly after moulding. All of that can happen here.
Whether volume is growing
If the forecast will double in eighteen months, we'll design the compression tool with LSR conversion in mind — same part geometry, tool built to migrate.
Related routes
Where this connects.
Silicone injection moulding
High-consistency silicone injected under heat into steel tooling. For a component you'll buy every quarter for years, this is the lowest cost per…
Read moreLSR injection moulding
Two-part liquid silicone metered, mixed, injected cold and cured hot. The cleanest route we have for medical, wearable and electronics parts at…
Read moreBatch manufacturing
For volumes measured in the hundreds or low thousands per batch, released on your schedule rather than ours. Bridge tooling, dedicated compression,…
Read moreDesigned and developed in the UK. UK moulding capability, with some higher-volume production placed with trusted partners where that's the right commercial answer.
At a glance
The ideas in pictures.
Which route suits your quantity
Swipe to see the whole diagram
From drawing to delivered parts
- 01Drawing or sampleYour part and where it is used
- 02Material and routeCompound and process agreed
- 03PrototypeReal parts to test
- 04Sign-offYou approve the samples
- 05Production toolBuilt for your volumes
- 06Batches and checksInspected and delivered
Swipe to see the whole diagram
Get in touch
Tell us the part, the volume, and the timeline.
Rough annual volume, target unit price, and any deadlines. That's enough to work out whether compression, LSR injection or something else is the right tool.
Real people, a real workshop
You deal with the people who make it.
No call centre and no middlemen. When you contact TCI Products, you speak to the team who design, build and check your mould.
- A real Warwickshire workshopUnit 15, Waterloo Park, Bidford-on-Avon, Alcester B50 4JG.
- Real people on the phoneCall the team on 01789 224228, Monday to Friday.
- The same team on every jobDesign, production and aftercare come from the people you see here.
- Part of TCI GroupFive specialist brands, one engineering team. Visit TCI Group.
Thomas LaneManaging Director
George PrestonDesign & Project Manager
Kelly BallingerHead of Partnerships
Jim AndertonProduction Manager
TheodoreEmployee Welfare