The material and its cost per kilo
Pot and sprue waste matters more on expensive grades.
Middle route · rubber and silicone
Transfer moulding.
Material is loaded into a pot above the tool and pushed through sprues into closed cavities. It fills more evenly than compression and costs less to tool than injection. For the right part, it's the sensible middle.
Where it fits
When compression leaves too much flash and injection is too big a jump.
In compression, the rubber sits in an open cavity and the tool closes on it. That's simple and cheap, but it can push inserts out of position and leaves flash along the whole parting line.
Transfer moulding closes the tool first, then forces material in through small channels. Inserts stay where they were placed, fine features fill more consistently, and flash is thinner and easier to remove.
It uses the same solid-gum materials as compression — silicone, EPDM, nitrile, fluorocarbon — so the material choice stays wide. And the tooling is simpler than a full injection tool, which keeps the upfront investment proportionate for mid-volume parts.
The trade-off is waste: the material left in the pot and sprues is cured and scrapped. For expensive grades we look hard at whether injection or careful compression would be kinder on material cost.
What it's good at
Three jobs transfer does well.
Parts with inserts
Metal bushes, threaded inserts and rigid carriers stay located because the tool is closed before material moves. See insert moulding.
Multi-cavity small parts
One pot can feed many cavities evenly, which suits grommets, small seals and boots in steady mid-volume demand.
Fine or deep features
Material pushed under pressure fills thin ribs and deep pockets more reliably than a pre-form squeezed in an open cavity.
How it runs
Load, close, transfer, cure.
The cycle is slightly longer than compression, but the parts that come out need less work.
Load inserts
Where the part has inserts, they're primed where needed and placed in the closed-tool locations.
Charge the pot
A measured slug of prepared compound goes into the transfer pot above the cavities.
Transfer under pressure
A plunger forces the material through sprues into the heated cavities. Fill is even and controlled.
Cure and demould
Parts cure in the tool, release, and move to deflash. The pad left in the pot is removed and scrapped.
To quote it
What decides whether transfer is right.
Whether there are inserts
Inserts push the decision towards transfer or injection and away from open compression.
Annual volume
Transfer suits the middle band. Very low volumes favour compression; very high volumes usually favour injection.
How much flash you can live with
Transfer leaves less than compression, more than well-tooled injection. We'll show you samples.
Related routes
Where this connects.
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…
Read moreInsert moulding
A pre-made insert — a threaded stud, a metal contact, a printed circuit, a stiffening plate — placed into the tool cavity, then silicone or rubber…
Read moreSilicone 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 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 idea in a picture.
Which route suits your quantity
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
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