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5
elastomer families molded in-house
Electrical & Electronic Rubber Parts
Custom Electrical & Electronic Rubber Parts
Molded silicone, LSR, EPDM and conductive elastomer components engineered for the dielectric, sealing and EMI demands of electrical and electronic products — built to your drawing, not pulled from a catalog.
Engelhardt molds grommets, keypads, EMI shielding gaskets, enclosure seals, insulators and anti-vibration mounts for electronics manufacturers worldwide. We control compound, tooling and quality in one ISO 9001 and IATF 16949 certified plant.
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±0.05 mm
achievable molded tolerance (RMA A1)
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ISO 9001
IATF 16949
IATF 16949
certified quality system
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3,000 t/yr
rubber + silicone molding capacity
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In-house
mold design & tooling
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Since 2009
rubber & silicone molding experience
Engineering Insights
Why Electrical & Electronic Rubber Parts Fail Early — and How to Spec Them Right
Custom rubber parts for electrical and electronic products fail in the field for one reason far more often than any other — the compound was chosen for the wrong property. An electrical or electronic rubber part has to insulate, seal, shield, cushion or actuate inside powered equipment, and each of those jobs demands a different elastomer. Pick a familiar oil-resistant grade by habit instead, and eighteen months later the insulation tracks or the seal leaks.
The three failure modes we see most often
Dielectric mismatch
Nitrile rubber is a poor electrical insulator, yet it is routinely specified for parts that sit across live conductors because it is cheap and oil-resistant.
Compression set
An enclosure gasket under constant load takes a permanent deformation, loses contact force, and the IP seal opens a leak path for moisture.
Ozone and UV cracking
Ozone attacks the unsaturated polymer chains in natural rubber, SBR and nitrile — surface cracks propagate until the part splits at a stress point.
Each of these traces back to the same root cause. Off-the-shelf rubber components are formulated for a generic average application, so the elastomer, hardness and cure system never match the dielectric strength, temperature range and chemical exposure of your specific product.
Specifying it right — the Engelhardt approach
We start from the electrical requirement, not the cheapest compound. The elastomer is selected for measured dielectric and thermal data, the part is molded on tooling cut for your geometry, and it is verified in our own laboratory before the first production lot ships.
This page is organized the way an engineering review runs — product range and material selection, a custom-versus-catalog comparison, our manufacturing and quality controls, certifications, and a transparent procurement guide. Engelhardt has produced custom molded rubber components since 2009, so the guidance here reflects production practice rather than brochure copy.
Engineering Insights
Engelhardt Electrical & Electronic Rubber Parts — Product Range & Material Selection
We mold six families of rubber components for electrical and electronic assemblies. Each is a custom rubber part — produced from your drawing or a reverse-engineered sample, in the compound the application actually needs.
Grommets & Cable Seals
Edge-protection and sealing grommets that pass wires and cables through metal and plastic enclosures.
- Open, blind and multi-hole patterns
- EPDM or silicone for outdoor use
Silicone Rubber Keypads
Molded silicone rubber keypads with defined tactile feel and consistent actuation force for user interfaces.
- Carbon/gold contact pills
- Laser-etched, backlit-ready
EMI Shielding Gaskets
Conductive rubber gaskets that seal an enclosure and block electromagnetic interference at the same seam.
- Silver/Nickel-graphite filled silicone
- Molded or die-cut profiles
Enclosure & Connector Seals
Custom rubber gaskets and O-rings that hold an IP rating across temperature and pressure cycling.
- Compression-set-resistant
- Two-shot/insert-molded
Insulators & Bushings
Molded rubber insulators that maintain electrical isolation while locating and protecting components.
- High dielectric-strength silicone
- UL 94 flame-rated options
Anti-Vibration Mounts
Isolation mounts and rubber feet that protect circuit boards and assemblies from shock and resonance.
- Tuned durometer damping
- Bonded metal inserts
Material Selection Matrix
| Compound | Dielectric strength | Temp. range | EMI / conductivity | Flame rating | Best-fit E&E parts |
|---|---|---|---|---|---|
| Silicone (VMQ) | 20–25 kV/mm | -60 to 200 °C | Insulator | UL 94 V-0 | Keypads, insulators |
| Liquid Silicone (LSR) | 20–25 kV/mm | -50 to 200 °C | Insulator | UL 94 V-0 | Precision seals |
| EPDM | Alto | -40 to 150 °C | Insulator | Flame-retardant | Outdoor grommets |
| Conductive Silicone | Conductive | -50 to 200 °C | EMI shielding | V-0 grades | EMI gaskets |
Engineering Insights
Custom-Molded vs. Off-the-Shelf Rubber Parts — Performance Comparison
A catalog grommet costs less on the line item — the question every engineering manager should ask is what it costs across the life of the product.
| Criterion | Off-the-shelf rubber part | Engelhardt custom-molded part |
|---|---|---|
| Compound match to electrical spec | Generic grade — dielectric not verified | Selected for measured dielectric & thermal data |
| Dimensional tolerance | ≈ ±0.25 mm catalog typical | to ±0.05 mm (RMA Class A1) |
| Geometry fit to enclosure | Nearest stock size | Molded to your exact drawing |
| Flame / RoHS / REACH compliance | Not guaranteed | Compound documented to UL 94, RoHS, REACH |
Total Cost of Ownership — How to Read It
SILVER-TIER FRAMEWORK · directional, not a published ROI figure
How Engelhardt Manufactures Your Parts — Molding, Tooling & Quality Control
The most common buyer worry we hear is simple: can an overseas molder actually hold the specification, lot after lot? The answer is built into how the plant is run.
Behind those presses is a team built around custom rubber molding — compound chemists, tooling engineers and molding specialists with more than a decade of years of experience. That depth lets us treat a demanding electrical part as a routine job rather than an experiment, and it means one supplier can cover your full bill of materials: alongside electrical and electronic parts we mold custom molded rubber parts for sealing and industrial use, plus silicone and high-performance plastic components.
Compound control before the part is ever molded
Quality in a molded rubber part is decided in the mixing room. Our automated up-stream mixing system feeds material to the mixer against a preset recipe, holding batching accuracy within 0.3%. That removes the manual ingredient errors — mis-matched, missing or double-dosed material — that quietly shift a compound’s dielectric and mechanical behavior between lots.
In-house tooling and a testing laboratory
Mold design and manufacture run in-house on high-speed machining equipment, so tooling iterations stay fast and your part geometry is never sent to a third party. Every compound then passes our own laboratory before production — Mooney viscometers and moving-die rheometers verify the compound, while salt-spray, humidity and heat-aging chambers confirm it survives the service environment.
Traceability — built into the system, not promised on a slide
Since 2017 the plant has run ERP, MES and QMS systems. Every part carries forward and reverse batch traceability — from incoming raw material through mixing, molding, trimming and inspection to the shipped lot. If a question ever arises, we can trace it to the exact material, machine, operator and process step.
Certifications & Compliance for Electrical Applications
For an electronics buyer, certifications answer two questions: is the quality system disciplined, and will the compound clear regulatory review.
ISO 9001
Quality management system
IATF 16949
Automotive-grade process
RoHS
Restricted substances
REACH
EU chemical compliance
UL 94
Flame-rated (V-0)
The IATF 16949 certification is worth a closer look. It is an automotive-sector standard, and it is significantly stricter than ISO 9001 alone — it demands defect-prevention discipline, traceability and process control that an electronics program benefits from directly.
What the compliance marks mean for your part
UL 94: rates flammability from HB up to V-0 — V-0 compounds self-extinguish within 10 seconds and do not drip flaming material, the grade most electronics enclosures require.
RoHS: keeps restricted substances such as lead and cadmium out of the compound — mandatory for electronics sold into the EU.
REACH: documents the chemical content of the elastomer so your product clears EU registration.
ASTM D2000: gives every compound a standard line-callout, so the material on your drawing is unambiguous.
Procurement Guide — MOQ, Tooling Cost, Lead Time & Sampling
Most rubber-molding pages stop at “contact us for pricing.” Procurement teams need to plan a budget before that call — so here is how custom rubber part pricing actually works.
Tooling type
Aluminum / bridge tooling is faster and lower-cost for early and mid volumes; hardened steel tooling suits sustained high-volume production.
Part geometry & cavities
Complexity and cavity count set tooling cost; more cavities lower the per-part price at volume.
Compound
LSR and conductive silicone cost more than EPDM or neoprene; the matrix above shows the relative scale.
Order volume
Volume sets the molding process and amortizes tooling — the single biggest lever on per-part price.
Buyer Advisory — three questions to settle before you commit tooling
- Who owns the mold? At Engelhardt the tooling you pay for is yours — confirmed in writing on the quotation.
- What happens if the first article fails? Agree the first-article review and re-cut path up front; we run sampling before the production lot is released.
- What is the communication protocol? A named engineer owns your project from DFM review through production, so design iterations do not get lost across a time zone.
We support low-volume launches as well as sustained production — the molding process is matched to your volume rather than forcing a high minimum, and tooling lead time and sampling are scoped against your specific part during quotation. For exact tooling cost, MOQ and a lead-time estimate, send your drawing or a sample part, and you will receive a quotation built on your real parameters rather than a placeholder range.
Engineering & Procurement Solutions
Streamline your component sourcing process with our data-driven engineering tools and evaluation frameworks, specifically designed for enterprise electronics manufacturers.
Compound Selector
Evaluate physical properties, thermal resistance, and chemical compatibility to identify the optimal rubber matrix for your electrical applications.
Evaluation Parameters
- Dielectric strength & insulation ratings
- Operating temperature extremes
- Compression set & longevity metrics
Comprehensive RFQ Checklist
Ensure all critical project parameters are rigidly defined prior to quotation. Eliminate hidden costs and prevent downstream engineering delays.
Checklist Coverage
- Mold cavity & tooling life expectations
- Tolerance standards (RMA A1/A2/A3)
- First Article Inspection (FAI) requirements
Custom vs. Catalog Analysis
A definitive cost-benefit framework comparing bespoke molded components against off-the-shelf catalog solutions for enterprise scaling.
Analysis Metrics
- Total Cost of Ownership (TCO) modeling
- IP ownership & supply chain security
- Scalability & assembly integration impact
Domande Frequenti
Clear, direct answers regarding compound properties, tooling economics, and production protocols for enterprise electronics procurement.
Which rubber compound is best for electrical and electronic parts?
For insulation, silicone and LSR lead — they offer 20–25 kV/mm dielectric strength and a wide temperature range. EPDM suits outdoor sealing, conductive silicone handles EMI shielding, and nitrile should be kept away from live-circuit positions because it is a poor insulator. The material selection matrix above maps each compound to its best-fit part.
Can you match or reverse-engineer an existing rubber part?
Yes. Send a sample or a drawing. We identify the elastomer family, confirm dimensions and properties in our laboratory, and quote a custom-molded equivalent — useful when an original supplier is no longer available.
What is the minimum order quantity for custom rubber parts?
There is no single fixed MOQ. We match the molding process to your volume, which lets us support low-volume launches as well as high-volume production. Your MOQ is confirmed on the quotation for your specific part.
Who owns the mold after it is made?
The tooling you pay for belongs to you. Mold ownership is stated in writing on the quotation, and your part geometry is never sent to a third party because tooling is designed and cut in-house.
Do your compounds meet RoHS, REACH and UL flame ratings?
Yes. We supply RoHS and REACH documentation and material certificates with the part, and offer UL 94 flame-rated grades up to V-0. Confirm the exact grade you need during quotation so it is locked in before tooling is cut.
What dielectric strength can a molded rubber part provide?
Silicone and LSR compounds typically provide 20–25 kV/mm of dielectric strength, tested to ASTM D149. The usable figure depends on the specific compound and part thickness, which we confirm against the production grade’s datasheet.
Can you mold rubber over metal or plastic inserts?
Yes. We produce insert-molded and bonded rubber-to-metal and rubber-to-plastic components — common for connector seals, anti-vibration mounts and grounded EMI parts. Transfer and injection molding give the closed-mold consistency these parts need.
How do you keep quality consistent between production lots?
Compound batching is automated to within 0.3% accuracy, and every lot is logged in our MES system with forward and reverse traceability. The part shipped a year into production is held to the same compound and process record as the approved sample.
How long does tooling and first sampling take?
Tooling lead time depends on part complexity and tooling type — aluminum tooling is faster than hardened steel. We scope tooling lead time and the first-article sampling schedule against your drawing during quotation, and run sampling before releasing the production lot.
