If you’re searching for “casting rubber parts,” you likely want to know how to create durable, precise rubber components for your products—or how to choose the right ones. Simplemente poner, casting rubber parts are rubber components made by pouring liquid rubber materials into molds, then curing them to take the mold’s shape. This process works for everything from small gaskets to large industrial seals, and it’s favored for its flexibility, rentabilidad, and ability to produce complex designs. Al final de esta guía, you’ll understand how the process works, which materials to use, desafíos comunes, and how to get the best results for your project.
1. What Are Casting Rubber Parts, and Why Do They Matter?
Antes de sumergirse en los detalles, aclaremos los conceptos básicos. Casting rubber parts differ from other rubber manufacturing methods (like extrusion or injection molding) because they rely on liquid rubber—no high pressure or heat is needed to force material into molds. En cambio, the liquid rubber flows naturally, haciéndolo ideal para:
- Formas complejas: Detalles intrincados (like grooves, agujeros, o logotipos personalizados) that are hard to achieve with other methods.
- Low to medium production runs: A diferencia del moldeo por inyección, que requiere herramientas costosas, casting works well for small batches (10–1,000 unidades) or prototypes.
- Soft or flexible parts: Materials like silicone or urethane can be cast to be soft (for medical pads) or rigid (for industrial bumpers).
Ejemplo del mundo real: Medical Device Seals
A client in the medical industry once needed 50 custom seals for a portable oxygen device. Extrusion would have required tooling costs of $5,000+, and injection molding wasn’t feasible for such a small run. Usamosliquid silicone casting to create the seals: the liquid silicone flowed into a 3D-printed mold (costing just $300), cured at 120°C for 20 minutos, and the final parts met FDA standards for biocompatibility. This saved the client 90% on tooling and delivered parts in 5 days—proving why casting is a go-to for niche or low-volume needs.
2. The Core Casting Rubber Process: Paso a paso
The casting process varies slightly by material, but the core steps are consistent. Below is a breakdown of the most common method: room-temperature vulcanization (RTV) fundición—used for silicone and urethane rubbers.
| Paso | Action | Detalles clave |
|---|---|---|
| 1 | Preparación de moho | limpiar el molde (usually made of aluminum, acero, or 3D-printed resin) to remove dust or debris. Aplicar un agente de lanzamiento (like silicone spray) to prevent rubber from sticking. |
| 2 | Rubber Mixing | Combine liquid rubber base with a curing agent (ratio depends on material: P.EJ., 10:1 para silicona). Mix slowly to avoid air bubbles—bubbles cause weak spots in the final part. |
| 3 | Torrencial | Pour the mixed rubber into the mold. Tilt the mold slightly to ensure the rubber fills all gaps (especialmente para formas complejas). Para grandes partes, vierta en capas para reducir las trampas de aire. |
| 4 | Desgásico (Opcional) | Coloque el molde en una cámara de vacío durante 5 a 10 minutos para eliminar las burbujas de aire.. Esto es fundamental para piezas que necesitan alta resistencia. (como juntas industriales). |
| 5 | Curación | Deje que el caucho se cure a temperatura ambiente. (20–25 ° C) durante 4 a 24 horas, o usar calor (60–120 ° C) Para acelerar el curado (1–2 horas). El tiempo de curado depende del espesor del material.: una pieza de 1 cm cura más rápido que una pieza de 5 cm. |
| 6 | Fundamento & Refinamiento | Sacar la pieza del molde.. Recortar el exceso de goma (llamado "Flash") con un cuchillo afilado o una troqueladora. Para piezas de precisión, lijar los bordes o pulir las superficies. |
Pro Tip for Beginners: Avoiding Air Bubbles
Las burbujas de aire son las #1 error que cometen los nuevos fabricantes. During our work with a startup making silicone phone cases, Su primer lote tuvo 30% of parts with bubbles. La solución? They started mixing the rubber slower (200 RPM instead of 500 Rpm) and degassed the mold for 8 minutos (arriba de 3). After that, bubble rates dropped to 2%—a simple adjustment that saved them time and material waste.
3. Choosing the Right Rubber Material for Casting
Not all rubbers work for casting. The material you pick depends on your part’s use case (P.EJ., resistencia a la temperatura, exposición química) y presupuesto. A continuación se muestra una comparación de las opciones más populares.:
| Material | Propiedades clave | Mejores usos | Costo (Por kg) |
|---|---|---|---|
| Caucho de silicona líquida (LSR) | – Resistencia a la temperatura: -60° C a 230 ° C- Biocompatible (Aprobado por la FDA)- Low toxicity | Dispositivos médicos (focas, catéteres), productos para bebés (teethers), Herramientas de cocina (baking mats) | $25- $ 40 |
| Urethane Rubber | – Alta resistencia a la abrasión- Flexible (Shore A 30–90 hardness)- Buena resistencia química (aceites, solventes) | Piezas industriales (rodillos, parachoques), sellos automotrices, juguetes | $15- $ 30 |
| Neoprene Rubber | – Water resistance- Rango de temperatura: -40° C a 120 ° C- Resistance to ozone and UV | Partes marinas (boat seals), equipo al aire libre (wetsuit zippers), HVAC gaskets | $20- $ 35 |
| Natural Rubber | – High elasticity- Bajo costo- Poor oil/chemical resistance | Piezas de uso general (erasers, door stoppers), low-stress gaskets | $10- $ 20 |
Critical Data Point: Temperature Limits
According to the Rubber Manufacturers Association (RMA), choosing a material outside its temperature range can reduce part lifespan by 70%. Por ejemplo, a natural rubber seal used in a car engine (que alcanza 150 ° C) will crack in 6 meses, while an LSR seal in the same spot will last 5+ años. Always match the material to your part’s operating environment.
4. Common Challenges in Casting Rubber Parts (y como arreglarlos)
Even experienced manufacturers face issues with casting. A continuación se encuentran la parte superior 3 problems and proven solutions, based on our 10+ años en la industria:
Desafío 1: Part Warping After Curing
Warping happens when the rubber cures unevenly—usually because the mold is too hot in some areas or the rubber is too thick.
- Solución: Use a mold with uniform thickness (no sudden changes from 1cm to 5cm). Para partes gruesas, cure at a lower temperature (P.EJ., 60°C instead of 100°C) and extend curing time by 50%. We fixed a client’s warped urethane rollers by adjusting the mold design to have a consistent 3cm thickness—warping stopped entirely.
Desafío 2: Rubber Sticking to the Mold
Sticking occurs when the release agent is missing or the mold is dirty.
- Solución: Aplicar un agente de lanzamiento dos veces (once before pouring, una vez después de que se endurezca la primera capa). Para moldes de resina, Utilice un agente desmoldante a base de petróleo. (Los aerosoles de silicona pueden dañar la resina con el tiempo.). Una vez, un fabricante de muebles desperdició 20 kg de caucho porque se saltó el agente desmoldante, después de agregarlo., se tomó el desmoldeo 2 minutos por parte.
Desafío 3: Dureza inconsistente
Si algunas partes son más blandas que otras, la relación caucho-agente de curado está apagada.
- Solución: Utilice una balanza digital para medir la base y el agente de curado. (P.EJ., 100base g + 10g agente de curado para un 10:1 relación). Mezclar exactamente 2 minutos (no más, no menos)—mezclar demasiado puede romper el caucho. We helped a toy maker fix this by switching from a manual scale to a digital one; hardness variation dropped from 15 Costa a 2 Costa a.
5. Applications of Casting Rubber Parts Across Industries
Casting rubber parts are everywhere—you probably use them daily without realizing it. Aquí hay 4 key industries and their most common uses:
1. Automotor
- Focas: Door seals, Juntas de motor (made of neoprene for oil resistance).
- Parachoques: Small urethane bumpers to protect dashboard components.
- Hoses: Flexible silicone hoses for coolant systems (resist high temperatures).
2. Médico
- Dental Trays: Custom silicone trays for teeth whitening (biocompatible).
- Device Seals: FDA-approved LSR seals for insulin pumps and heart monitors.
- Masks: Soft silicone masks for respiratory therapy (comfortable for long wear).
3. Bienes de consumo
- Kitchen Tools: Silicone baking mats, utensil grips (a prueba de calor).
- Juguetes: Rubber wheels for toy cars (urethane for durability), silicone teething toys.
- Electrónica: Rubber gaskets for phone cases (impermeabilización).
4. Industrial
- Rodillos: Urethane rollers for conveyor belts (resistente a la abrasión).
- Focas: Large neoprene seals for tanks and pipes (impermeable).
- Vibration Dampeners: Soft silicone dampeners for machinery (reduce noise).
6. Yigu Technology’s Perspective on Casting Rubber Parts
En la tecnología yigu, Hemos trabajado con 500+ clients on casting rubber parts, and one trend stands out: the demand forsostenible, materiales de alto rendimiento está creciendo. More manufacturers are asking for recycled urethane or plant-based silicone to reduce their carbon footprint—without sacrificing quality. We’ve also noticed that small businesses (like startups) are increasingly choosing casting over other methods because of its low upfront costs. Nuestro consejo? Don’t cut corners on mold quality: a well-made mold (even a 3D-printed one) will produce consistent parts and save you money long-term. We also recommend testing 5–10 prototype parts before full production—this catches issues early, like warping or incorrect hardness, that could derail a large order.
7. FAQ About Casting Rubber Parts
Q1: How long does it take to make casting rubber parts?
A: Para piezas pequeñas (P.EJ., 5cm gaskets), the process takes 1–2 days (mixing, torrencial, curación, refinamiento). Para grandes partes (P.EJ., 50cm rollers), it can take 3–5 days (longer curing time).
Q2: Can casting rubber parts be recycled?
A: Sí, but it depends on the material. Urethane rubber can be ground into pellets and reused for low-stress parts (like door stoppers). Silicone is harder to recycle, but some companies (Como yigu) offer take-back programs for used silicone parts to repurpose them.
Q3: Is casting cheaper than injection molding?
A: Para carreras pequeñas (bajo 1,000 regiones), Sí. Injection molding requires tooling costs of $5,000–$50,000, while casting molds cost $300–$3,000. Para carreras grandes (10,000+ regiones), injection molding becomes cheaper per unit.
Q4: What’s the maximum size of a casting rubber part?
A: We’ve made parts as large as 2 medidores (industrial tank seals) and as small as 1mm (micro gaskets for electronics). The limit depends on the mold size and the rubber’s ability to flow evenly—large parts may need multiple pouring steps.
Q5: Are casting rubber parts waterproof?
A: Most are, if made with the right material. Silicone and neoprene are naturally waterproof; urethane can be coated with a waterproof sealant for extra protection. Always specify waterproofing needs to your manufacturer—this ensures they choose the right material and mold design.