Insert Molding
Insert Molding for Custom Silicone Components
LSRParts provides precision Insert Molding services for OEMs, Tier suppliers, and engineering teams that need reliable silicone parts built for production. We combine liquid silicone rubber molding, mold design, material selection, and secondary operations to deliver custom components that meet dimensional, functional, and repeatability requirements.
Our insert molding programs are designed for applications where silicone must bond to a plastic or metal substrate and perform consistently in demanding environments. Whether your project involves sealing, gripping, insulation, fluid control, or device protection, we support the full path from DFM review to mass production.
Insert Molding Built for Production
Insert molding is not just a tooling process. It is a manufacturing strategy that must account for material bonding, part geometry, process control, and long-term repeatability.
At LSRParts, we support custom insert molding for:
- ● Plastic substrates
- ● Metal inserts
- ● Single- and multi-cavity tooling
- ● Prototype and production programs
- ● High-volume repeat manufacturing
Typical insert molding applications include:
- ● Medical device seals and components
- ● Connector seals and wire seals
- ● Sensor and housing seals
- ● Grips and overmolded handles
- ● Valves, diaphragms, and fluid-control parts
- ● Electronics protection components
Our Insert Molding Capability
LSRParts focuses on custom silicone parts rather than standard off-the-shelf rubber products. For insert molding programs, we engineer each part around the customer's drawing, application, and performance requirements.
LSR Overmolding and Insert Molding Capability
| Parameter | Capability |
|---|---|
| Maximum Part Envelope | 300 × 200 × 100 mm |
| LSR Hardness | 10–80 Shore A |
| Mold Tolerance | ±0.01 mm |
| Typical Part Tolerance | ±0.05 mm |
| Mold Cavities | Single / Multi-cavity |
| Mold Life | 3–5 million shots depending on tooling |
| Plastic Substrates | PC, PA, PBT, PPSU, PPA, PEI, etc. |
| Metal Substrates | Aluminum, stainless steel, brass, copper |
| Bonding | Chemical / mechanical bonding strategy |
| Insert Molding | Supported |
| Typical Applications | Medical devices, connectors, seals, grips, electronics |
| Post Processing | Post-cure, trimming, printing, marking, assembly |
Engineering Support from DFM to Mass Production
A reliable insert molded part starts before the mold is built.
Our engineering team reviews:
- ● Part geometry
- ● Wall thickness
- ● Sealing features
- ● Draft and undercuts
- ● Flash requirements
- ● Material hardness
- ● Shrinkage behavior
- ● Tolerance targets
- ● Bonding requirements
- ● Expected production volume
This early DFM process helps identify manufacturing risks before tooling begins and gives customers a clearer path from prototype validation to stable production.
Typical Workflow
- 1DFM Review
- 2Material Selection
- 3Mold Design
- 4Tool Manufacturing
- 5T0/T1 Sampling
- 6Validation
- 7Production Approval
- 8Mass Production
- 9Inspection & Assembly & Packaging
Insert Molding Materials
We support a broad material matrix for custom silicone programs.
| Material | Target Applications |
|---|---|
| General Purpose LSR | Industrial / electronics |
| Medical Grade LSR | Medical devices |
| Food Grade LSR | Food / beverage / baby |
| Platinum-Cured Silicone | Medical / food contact |
| Optical LSR | Optical / lighting |
| Fluorosilicone | Automotive / fuel / chemical exposure |
| High-Temperature Silicone | Automotive / industrial |
| Low-Temperature Silicone | Outdoor / automotive |
| Electrically Conductive Silicone | Electronics / EMI |
| Thermally Conductive Silicone | Thermal management |
| Flame-Retardant Silicone | Electrical / automotive |
| Custom Compounds | Application specific |
We also evaluate the insert material, surface condition, and bonding strategy to help achieve stable adhesion and repeatable production.
Common Insert Molding Applications
Automotive & EV
- ● Connector seals
- ● Wire seals
- ● Battery seals
- ● Sensor seals
- ● Overmolded functional parts
Medical & Healthcare
- ● Septa
- ● Plunger tips
- ● Valves
- ● Diaphragms
- ● Device seals
- ● Silicone components with plastic or metal inserts
Pumps, Valves & Fluid Control
- ● Diaphragms
- ● Membranes
- ● Check valves
- ● Sealing components
- ● Precision fluid path parts
Electronics & Sensors
- ● Waterproof seals
- ● Housing seals
- ● Keypads
- ● Overmolded parts
- ● EMI-related silicone components
Food, Beverage & Baby Care
- ● Bottle valves
- ● Breast pump parts
- ● Food-grade seals
- ● Tubing and connected assemblies
Tooling and Manufacturing Capability
Insert molding quality depends heavily on the mold. LSRParts provides precision tooling support in-house for prototype and production requirements.
| Tooling Capability | Specification |
|---|---|
| DFM | Yes |
| CAD | SolidWorks / CAD |
| Mold Flow Review | Supported |
| CNC | 3-axis / 5-axis CNC |
| EDM | Sinker EDM / Wire EDM |
| Rapid Tooling | Aluminum tooling |
| Rapid Tool Life | Approx. 100–10,000 cycles |
| Production Tooling | Hardened steel tooling |
| Common Mold Steel | P20 / NAK80 / H13 / S136 / 420 |
| Stainless Tooling | 316 / 420 where applicable |
| Aluminum Tooling | 6061 / 7075 |
| Tool Surface Finish | Ra 0.8 μm or better where required |
| Prototype Tool Lead Time | Benchmark approx. 10–12 days |
| Production Tool Lead Time | Benchmark approx. 3–6 weeks |
| Sampling | T0 / T1 / validation |
| Multi-Cavity Tooling | Yes |
| High-Volume Tooling | Yes |
Secondary Operations for Insert Molded Parts
We can integrate downstream operations to reduce supplier complexity and support production-ready delivery.
- ● Post-curing
- ● Precision trimming
- ● Die cutting
- ● Punching
- ● X / Y slitting
- ● Valve slitting
- ● Pad printing
- ● Silk screening
- ● Laser marking
- ● Drilling
- ● Bonding
- ● Dipping
- ● Cutting & coiling
- ● Assembly
- ● Functional testing
- ● Inspection
- ● Custom packaging
Why Choose LSRParts for Insert Molding
LSRParts is built for customers who need more than a molded part. We support programs that require engineering input, repeat production, and consistent quality.
What We Prioritize
- ● Custom silicone parts for real applications
- ● Production-focused insert molding programs
- ● DFM and engineering support
- ● Stable quality for repeated orders
- ● OEM and Tier supplier requirements
- ● Medium to high-volume production
What We Are Not
- ● A commodity rubber reseller
- ● A standard catalog parts supplier
- ● A low-volume, one-off job shop
Our focus is on high-value, repeat-production silicone components.
Ideal Customers for Insert Molding
Our insert molding service is a strong fit if you have:
Custom drawings or 3D files
New tooling requirements
Annual demand above 100,000 pcs
Precision or functional requirements
Prototype-to-mass-production programs
Need for DFM and engineering support
Frequently Asked Questions
What is insert molding?
Insert molding is a process in which silicone is molded around a pre-placed plastic or metal insert to create a single integrated part.
Do you support both plastic and metal inserts?
Yes. We support plastic substrates such as PC, PA, PBT, PPSU, PPA, and PEI, as well as metal substrates including aluminum, stainless steel, brass, and copper.
Can you help with design before tooling?
Yes. We provide DFM review, material selection support, and mold design review before tooling begins.
Is insert molding suitable for high-volume production?
Yes. Our tooling and molding capability support prototype programs through high-volume mass production.
Can you provide secondary processing after molding?
Yes. We support post-curing, trimming, printing, marking, assembly, inspection, testing, and custom packaging.
Start Your Insert Molding Project
If you need a custom silicone insert molded part for automotive, medical, electronics, fluid control, or consumer device applications, LSRParts can support your program from concept to production.
Send us your drawings, 3D files, target material, annual volume, and performance requirements to begin DFM review and process planning.