Choosing the right materials for silicone Vacuum casting is make-or-break for your project—whether you’re making small-batch prototypes or low-volume production parts. The process relies on three core material types: prototype materials (to create the master template), mold materials (to make the flexible silicone mold), y casting materials (to produce the final parts). Abajo, we break down each category with clear data, use cases, and tips to help you pick the perfect materials for your needs.
1. Prototype Materials: El “Template” for Your Silicone Mold
The master prototype is the foundation of silicone vacuum casting—its material directly impacts how well the mold captures details and how durable the template is. Two main techniques are used to make prototypes, each with specific material strengths:
| Prototyping Technique | Materiales comunes | Propiedades clave | Mejor para | Performance Data |
| Mecanizado CNC | Abdominales, Aluminio, Stainless Steel | Alta precisión, acabado superficial liso | Prototypes needing tight tolerances (P.EJ., engranaje, partes mecánicas) | Tolerancias: ±0.01mm; Acabado superficial: Ra 0.2–0.8μm |
| SLA 3D Printing | Resinas de fotopolímero (P.EJ., Formlabs Grey Resin) | Complex shape capability, fine detail capture | Intricate designs (P.EJ., textured phone cases, small medical device components) | Acabado superficial: Ra 0.1–0.3μm; Detail resolution: 0.025mm |
Practical tip: If you’re making a prototype for a functional part (like a hinge), CNC-machined ABS is better—it has a higher impact strength (20 KJ /) than SLA resins (10–15 kJ/m²). For decorative parts with tiny patterns, Impresión 3D SLA is the way to go, as it can replicate details as small as a grain of sand.
2. Mold Materials: Flexible Silicone for Replicating Details
The mold material in silicone vacuum casting is almost always RTV (Room Temperature Vulcanization) silicone—a liquid that cures into a soft, elastic mold capable of capturing every detail of the master prototype. There are two main types of RTV silicone, each suited to different project needs:
| Mold Material Type | Propiedades clave | Mold Life (Uses) | Shrinkage Rate | Costo (Por kg) | Mejor para |
| Addition-Cure Silicone | Low shrinkage, high durability, no odor | 20–50 | 0.1–0.3% | \(25- )40 | High-volume low runs (30–50 partes) or complex prototypes (P.EJ., Piezas con sociedades) |
| Condensation-Cure Silicone | Lower cost, faster cure, slight odor | 10–20 | 0.5–1.0% | \(15- )25 | Pequeñas carreras (10–20 partes) or simple shapes (P.EJ., basic housings) |
Por qué esto importa: A low shrinkage rate (like 0.1–0.3% for addition-cure silicone) ensures your final cast parts match the master prototype’s size almost exactly. Por ejemplo, if your prototype is 10cm long, an addition-cure mold will produce parts that are 9.997–9.999cm long—critical for parts that need to fit together.
3. Casting Materials: El “Final Part” Materiales
Casting materials are what you inject into the silicone mold to make your end product. They range from common plastics to specialized rubbers and 耐高温 (high-temperature resistant) materiales, each tailored to specific performance needs:
| Casting Material Type | Specific Materials | Propiedades clave | Aplicaciones típicas | Performance Highlights |
| Thermoplastic-Like Resins | Abdominales, ordenador personal, PÁGINAS, Pensilvania, PMMA | Mimic production plastics; good strength/durability | Electrónica de consumo (fundas telefónicas), automotive accessories (perillas), artículos del hogar (container lids) | – Abdominales: Impact strength 20 KJ /- ordenador personal: Heat resistance up to 120°C; 透光率 (transmitancia de luz) 88%- PMMA: 透光率 92% (close to glass); resistente a los arañazos |
| Flexible Materials | Rubber, Soft PU Resins | Elasticity, grip, shock absorption | Empuñadura (controles remotos), focas (water bottles), O-rings (pipes) | Shore hardness: A 30–60; Elastic recovery rate >90% |
| High-Temperature Resistant Materials | PPS, PEI, Silicone Rubbers | Withstand extreme heat (150–250 ° C) | Componentes del motor, industrial sensors, high-heat tools | – PPS: Heat resistance 220°C- PEI: 250° C; chemical resistance to oils/solvents |
| Materiales especializados | CLORURO DE POLIVINILO, Conductive Resins | Customizable hardness (CLORURO DE POLIVINILO); electrical conductivity (conductive resins) | Cable insulation (CLORURO DE POLIVINILO), electronic connectors (conductive resins) | – CLORURO DE POLIVINILO: Hardness range Shore A 60–D 80- Conductive resins: Resistivity <10⁻³ Ω·cm |
Cost note: Thermoplastic-like resins (P.EJ., Abdominales, ordenador personal) costo \(18- )30 por kg, while high-temperature materials (P.EJ., PEI) can cost \(50- )80 por kg. This makes thermoplastics a better choice for budget-sensitive projects without extreme heat needs.
4. Key Factors to Choose the Right Materials for Your Project
With so many options, it’s easy to feel overwhelmed. Use these 5 factors to narrow down your choices—they’ll help you balance performance, costo, and usability:
- Functional Needs: If your part needs to be transparent (P.EJ., a lens), pick PMMA or transparent PC. If it needs to handle heat (P.EJ., a coffee maker part), go for PPS or PEI.
- Tamaño por lotes: Para 30+ regiones, use addition-cure silicone (longer mold life) to avoid re-making molds. For 10–20 parts, condensation-cure silicone saves money.
- Prototype Complexity: Intricate designs (P.EJ., tiny text) need Impresión 3D SLA with photopolymer resin—CNC machining can’t capture ultra-fine details.
- Costo: If you’re testing a new design, start with cheaper materials (P.EJ., condensation-cure silicone + PP resin) before upgrading to higher-cost options.
- Processing Ease: Partes flexibles (P.EJ., empuñadura) are easier to cast with soft PU resins—they demold faster than rigid materials and don’t crack the silicone mold.
La perspectiva de la tecnología de Yigu
En la tecnología yigu, we believe material selection for silicone Vacuum casting should align with both project goals and budget. For clients making functional prototypes, we often recommend CNC-machined ABS for masters (precisión + durabilidad) and rigid PC/PA casting resins (mimic production parts). For complex, piezas decorativas, Impresión 3D SLA + addition-cure silicone works best—captures details while keeping mold costs low. We also guide clients away from over-specifying: if a part doesn’t need high heat resistance, choosing PC over PEI cuts costs by 50% without sacrificing quality. Our goal is to help you get the right materials for the job, not the most expensive ones.
Preguntas frecuentes
- I need to make transparent parts—what casting material should I use?
Opt for PMMA or transparent PC. PMMA has a higher 透光率 (92% VS. PC’s 88%) and is cheaper (\(25- )30/kg vs. PC’s \(28- )35/kg), making it better for non-heat-exposed parts (P.EJ., cubiertas de exhibición). If the part needs to handle mild heat (up to 120°C), choose transparent PC for extra durability.
- How long does a silicone mold last, and what affects its life?
Mold life depends on the material: addition-cure silicone lasts 20–50 uses, mientras condensation-cure lasts 10–20. Factors like casting material (abrasive resins wear molds faster) and demolding care (pulling parts gently vs. tearing) also matter. To extend life, use mold release spray and avoid casting high-temperature resins (over 200°C) in standard RTV silicone.
- Can I use silicone Vacuum casting for food-safe parts?
Yes—but you need food-grade materials. Elegir FDA-approved silicone para moldes (P.EJ., Dow Corning 734) and food-safe casting resins (P.EJ., food-grade PP or silicone rubber). Avoid materials like PVC (not food-safe) and always ask for certification to ensure compliance with safety standards.
