Precision silicone overmolding · drawing review → sampling → volume
We build to your drawing: structural parts, appearance parts and overmoulded assemblies, in materials from food-contact to medical skin-contact, by compression, LSR injection or multi-material overmoulding. This page sets out what we make, how materials are specified, how we work with brands, and what happens between a sample and a shipment.
What we make
All four are called "custom silicone", but the engineering is not the same. Get the category right first, and quotes and lead times become comparable.
Silicone bonded to metal, plastic, PCBA or glass becomes one part: silicone provides sealing, damping, grip and insulation, the substrate provides stiffness and conductivity.
Thin walls, optical parts, two-shot colour and micro features run on LSR: walls in the 0.2 mm range, tighter dimensional control and faster automated cycles than compression.
Watchbands, sleeves, grips and decorative parts sell on colour, texture, rebound and feel — so the work sits in tool texturing, colour matching and surface finishing.
A function sits on top of the structure: UL94 for flame retardance, volume resistivity for conductivity, interface resistance for thermal, migration testing for food contact.
Process routes
| Route | Best for | Volume and cycle | Watch out for |
|---|---|---|---|
| Compression moulding (HCR) | Simple to medium geometry, many colour and hardness variants | Small to medium volume; flexible colour/hardness changes | Labour-heavy; flash and appearance depend on tool and operator |
| LSR injection moulding | Thin, precise, two-shot, automation-friendly parts | High volume; fast cycle, good part-to-part consistency | Higher tool precision; stricter preparation and contamination control |
| Overmoulding / multi-material | Parts combining silicone with metal, plastic or PCBA | Project-based; longest tooling and validation cycle | Interface chemistry decides the outcome; the material pair must be validated and frozen |
The full decision logic is on capabilities; structural limits, common defects and validation for each route are broken out in the process notes section.
Materials and compliance
Change the same part to a food-contact or medical grade and the formulation, cure system and validation all change. The table shows the usual directions and the documents that go with them; grades and available reports are confirmed per project.
| Application | Typical requirements | Documents to prepare |
|---|---|---|
| Food contact (cookware, feeding, drinking) | FDA 21 CFR 177.2600, LFGB, sensory testing | Compliance declaration, migration test report, batch traceability |
| Medical and skin contact (monitoring, care, wearables) | ISO 10993 series, cytotoxicity, sensitisation and irritation | Biocompatibility reports, sterilisation compatibility, change control |
| Flame-retardant protection (energy, power, industrial) | UL94 V0, graded by thickness | Flame rating reports, glow-wire and tracking data |
| Conductive and thermal (sensing, heat spreading) | Volume resistivity, interface resistance, compression set | Formulation notes, electrical data before and after ageing |
Properties and grade differences are in the property library; validation scope and equipment are on R&D and testing. We do not claim certifications we cannot evidence — what we can supply is what we will show.
How we work
You own the drawing, material and acceptance criteria; we own tooling, moulding, quality and delivery. Suited to brands and OEMs whose structure and supply chain are already fixed.
Structure review, material selection and appearance engineering developed jointly, with a producible design and samples as the output. Suited to teams that have a product idea but no drawing yet.
Colour, marking, packaging and documentation replaced on an existing structure and delivered under your brand. Suited to e-commerce brands and distributors testing a range.
All three can be combined with advisory services; the responsibility split and fee basis are in cooperation models, and drawing handling in confidentiality and NDA.
Sample to volume
Can it be moulded, where will it fail, and what should change — delivered as a risk list with recommendations.
Tool built to the agreed structure, first-off samples with a dimensional report and appearance standard.
Peel, leak, ageing, sterilisation or functional testing to the duty — a fail goes back one step, not forward.
Small volume to prove cycle time and yield; the material pair and process window are frozen.
Inspection against the sealed sample, retained samples and traceability; changes only through a written process.
Tooling and sample charging, ownership and timing are in sampling and tooling rules; the validation scope for each step is on R&D and testing.
Who we work with
Batch consistency and delivery matter most. Start from the product categories, then confirm the route on capabilities.
Can it be made at small volume, and how fast is a sample? Read the sampling rules first, then send drawings under the confidentiality process.
Interfaces, tolerances and validation. Go straight to the failure-analysis series in process notes, then the substrate and primer matrix.
Combined orders and steady supply. See the industry coverage in applications, and the contract manufacturing scope in services.
Industry applications
Medical monitoring parts, wearable bands and sleeves, consumer-electronics keys and seals, industrial insulation and potting parts, brand-device edge wrapping. Dairy parts are covered on milking liners and dairy equipment parts; robot skins, joint parts and smart-glasses nose pads on robot silicone parts and silicone nose pads; perforated padding for helmet liners, insoles, bra cups, pillows and seating on perforated silicone parts, with the tooling route on one-shot moulding of perforated silicone. English product pages are still being localised: send a part description or drawing and we will map it to the closest production line.
FAQ
Yes. Send the duty, the size envelope and the target cost and we will judge the structural direction; if it is feasible we produce sketches and a sampling plan. Start with the sampling rules.
There is no single number: it depends on geometry, tooling concept and material. Tooling, sampling and unit price are quoted separately so trial cost is not buried in the unit price — see sampling and tooling rules.
Compliance declarations and test reports against the actual grade and batch. Which reports exist and which standard revision was used is confirmed per project; we do not claim certifications we cannot evidence — see R&D and testing.
Yes, provided you supply the substrate and the interface can bond. We validate the material pair before fixing the process; substrates that cannot bond, such as untreated PP, are stated plainly rather than promised.
An NDA can be signed before drawings are sent; files are managed by project number and never enter public material. Terms are in confidentiality and NDA.
The reply covers feasibility, risk points, the recommended process route and what is still missing — usually within two to three working days.
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