What Are Custom Silicone Parts?
This is the commercial entry point to our business: send us a component that does not exist in any catalogue and we will engineer it. The work starts with a drawing review, because a moulded part is not a machined part and some tolerances that are normal on a CNC drawing are expensive or impossible in a mould. From there we propose a compound, design the tool, produce first-article samples for your testing, and only then move to production. Everything below describes that sequence in detail, because the sequence is what you are actually buying.
Applications
- Sealing, gasketing and waterproofing components to a custom profile
- Damping, isolation and cushioning parts
- Electrical insulation and thermal barriers
- Protective covers, sleeves, boots and grips
- Any moulded silicone part not available as a standard product
The Engineering Problem
Custom parts fail at the design stage more often than at the manufacturing stage. A tolerance that is achievable in metal may be a cost driver in rubber; a sharp internal corner will tear; an undercut will need a more complex tool; a wall that is too thin will not fill. All of these are cheap to fix before the tool is cut and expensive to fix after. That is why the drawing review comes first and why we push back on designs.
Product Features
- Engineer-reviewed drawing and 3D file before any quoting
- Explicit manufacturability feedback: draft, radii, wall thickness, tolerances, undercuts
- Compound proposal with the reasoning stated, not just a material name
- In-house mould design and manufacture
- First-article samples for fit, function and life testing
- Tooling cost refundable against volume production
- Locked process parameters and inspection records in production
Material Options
| Material | When we would choose it |
|---|---|
| Silicone (HTV) | The default for custom silicone parts: wide temperature range, weather resistance, electrical insulation, food and skin contact |
| Liquid silicone rubber (LSR) | Thin-wall, high-precision and long-life parts; translucent and optically clear grades available |
| EPDM / NBR / FKM | Where the service fluid or temperature rules silicone out — we will say so during the drawing review |
Material Properties
| Property | Typical value / comment |
|---|---|
| Hardness | 20-80 Shore A. Chosen against the mechanical duty, not against convenience |
| Tensile strength | Selected for the demoulding and assembly loads of your geometry |
| Elongation & tear | Determines how thin a section can be and how sharp a corner can be |
| Compression set | Critical for sealing and load-bearing parts |
| Temperature range | -60 to +230 C for silicone, compound dependent |
Specifications
| Parameter | What we work to |
|---|---|
| Dimensions | Moulded to your drawing or reverse-engineered from a sample |
| Tolerance | ±0.05 mm on critical moulded dimensions under controlled conditions; we will tell you which features are realistically tight |
| Operating temperature | -60 to +230 C for silicone (compound dependent) |
| Hardness | 20-80 Shore A |
| Colour | Black, natural/translucent, or matched to a physical sample |
| Surface finish | As-moulded, smooth, matte, textured, or defined gloss |
| Waterproof / IP | Sealing features designed in where the part forms part of an enclosure seal |
| Chemical resistance | Compound selected against your contact fluid list |
Production Process
- Drawing review. Manufacturability, tolerance and design comments issued before quoting
- Material selection. Compound proposed against temperature, chemistry and compression set
- Prototype. Where design risk is high, sample parts before committing to full tooling
- Tooling. Mould designed and built in-house; tooling cost refundable against volume
- Moulding. Compression or LSR moulding with locked parameters
- Inspection. Dimensional and hardness verification of critical characteristics
- Production. Repeat supply against the approved reference sample with change control
- Packaging. Bulk, trayed, bagged or kitted to your line requirement
Customization
- Colour matched to a physical sample
- Hardness varied by region within the same part
- Bonded metal or plastic inserts for press-fit or threaded attachment
- Laser marking or printed identification for traceability
- Secondary operations: deflashing, post-curing, bonding, sub-assembly
- Packaging and kitting configured for your production line
Tooling & Prototyping
Tooling is designed and built by us, which is why tooling cost can be refunded against volume production — we are not passing through a third-party toolmaker's price. Your quotation states the tooling cost, the refund condition and the volume at which the refund applies.
MOQ, Quality Control & Packaging
| Item | How it is handled |
|---|---|
| MOQ | Quoted per project against part size, tooling complexity and compound. Tooling refundability means a pilot order is usually workable |
| Quality control | Incoming material verification, in-process parameter checks, dimensional inspection, hardness testing and first-article approval |
| Packaging | Bulk, bagged, trayed or kitted |
| Documentation | Dimensional and hardness records with shipment; material sheet on request |
Material Compliance
The silicone compound we mould carries third-party SGS reports covering EU RoHS 2015/863, REACH SVHC, phthalates, PAHs, halogen, US FDA 21 CFR 177.2600, LFGB Section 30 and 31, and GB 4806.16-2025 - all Pass. A part's compliance depends on the compound grade, the colour and the process, so the grade is matched to your requirement at quotation stage. See the material compliance page for the report numbers.
Custom Silicone Parts — Frequently Asked Questions
A drawing or 3D file (STEP, IGES, PDF, DWG), or a physical sample. Plus the application, the service environment (temperature, chemicals, motion), the expected annual volume and any certification or documentation requirement.
Yes. Send the sample and we will measure it, propose a material, and issue a drawing for your confirmation before tooling. Where the original compound cannot be identified with certainty, we will recommend the closest equivalent and explain the difference.
Yes, ours or yours. We will not share drawings or tooling records with third parties.
Moulded elastomers shrink on cooling, flash at the split line, and vary with compound batch. A tolerance achievable on a machined part is often not achievable on a moulded one. We tell you which dimensions can be held tight and suggest designs that avoid needing the impossible ones.
It is quoted separately from the part price, and it is refundable against volume production. The exact volume threshold is stated in your quotation.
Yes, where the design risk justifies it. First-article samples are shipped with inspection data for your fit, function and life testing.
Yes, and the tooling refund model is designed to make that viable. We would rather run a pilot order and get the design right than start with a large commitment.
Related Products
Custom Rubber Parts
Bespoke rubber components in EPDM, NBR, FKM, NR, SBR and CR.
Silicone Molding
Compression and LSR moulding for custom silicone components.
Custom Tooling
In-house mould design and manufacturing, refundable against volume.
Related Industries
Robotics
Sealing, damping and protective components for industrial, collaborative and service robots.
Industrial Automation
Seals, gaskets and moulded parts for actuators, conveyors and machine frames.
Electronics
Enclosure sealing, insulation and interface components for controllers and instruments.
Drones & UAV
Waterproof sealing and vibration isolation for airframes and payloads.