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), и casting materials (to produce the final parts). Ниже, 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: А “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 | Общие материалы | Ключевые свойства | Лучше всего для | Performance Data |
| Обработка с ЧПУ | АБС, Алюминий, Stainless Steel | Высокая точность, smooth surface finish | Prototypes needing tight tolerances (НАПРИМЕР., передачи, mechanical parts) | Допуски: ±0.01mm; Поверхностная отделка: Ra 0.2–0.8μm |
| SLA 3D Printing | Photopolymer Resins (НАПРИМЕР., Formlabs Grey Resin) | Complex shape capability, fine detail capture | Intricate designs (НАПРИМЕР., textured phone cases, small medical device components) | Поверхностная отделка: Ra 0.1–0.3μm; Detail resolution: 0.025мм |
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, SLA 3D -печать 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) силикон—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 | Ключевые свойства | Mold Life (Uses) | Shrinkage Rate | Расходы (За кг) | Лучше всего для |
| Addition-Cure Silicone | Low shrinkage, high durability, no odor | 20–50 | 0.1–0.3% | \(25- )40 | High-volume low runs (30–50 деталей) or complex prototypes (НАПРИМЕР., детали с подрезок) |
| Condensation-Cure Silicone | Lower cost, faster cure, slight odor | 10–20 | 0.5–1.0% | \(15- )25 | Небольшие пробежки (10–20 деталей) or simple shapes (НАПРИМЕР., basic housings) |
Почему это важно: 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. Например, 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: А “Final Part” Материалы
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) материалы, each tailored to specific performance needs:
| Casting Material Type | Specific Materials | Ключевые свойства | Typical Applications | Performance Highlights |
| Thermoplastic-Like Resins | АБС, ПК, Стр, А, ПММА | Mimic production plastics; good strength/durability | Потребительская электроника (Телефонные чехлы), automotive accessories (ручки), household goods (container lids) | – АБС: Impact strength 20 KJ /- ПК: Heat resistance up to 120°C; 透光率 (легкая коэффициент пропускания) 88%- ПММА: 透光率 92% (close to glass); царапина |
| Flexible Materials | Rubber, Soft PU Resins | Elasticity, grip, shock absorption | Схватки (Дистанционное управление), уплотнения (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.) | Компоненты двигателя, industrial sensors, high-heat tools | – PPS: Heat resistance 220°C- PEI: 250° C.; chemical resistance to oils/solvents |
| Специальные материалы | ПВХ, Conductive Resins | Customizable hardness (ПВХ); electrical conductivity (conductive resins) | Cable insulation (ПВХ), electronic connectors (conductive resins) | – ПВХ: Hardness range Shore A 60–D 80- Conductive resins: Resistivity <10⁻³ Ω·cm |
Cost note: Thermoplastic-like resins (НАПРИМЕР., АБС, ПК) расходы \(18- )30 за кг, while high-temperature materials (НАПРИМЕР., PEI) can cost \(50- )80 за кг. 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, расходы, and usability:
- Functional Needs: If your part needs to be transparent (НАПРИМЕР., a lens), pick ПММА or transparent PC. If it needs to handle heat (НАПРИМЕР., a coffee maker part), go for PPS or PEI.
- Размер партии: Для 30+ части, 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 (НАПРИМЕР., tiny text) need SLA 3D -печать with photopolymer resin—CNC machining can’t capture ultra-fine details.
- Расходы: If you’re testing a new design, start with cheaper materials (НАПРИМЕР., condensation-cure silicone + PP resin) before upgrading to higher-cost options.
- Processing Ease: Flexible parts (НАПРИМЕР., схватки) are easier to cast with soft PU resins—they demold faster than rigid materials and don’t crack the silicone mold.
Перспектива Yigu Technology
В Yigu Technology, 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 (точность + долговечность) and rigid PC/PA casting resins (mimic production parts). For complex, decorative parts, SLA 3D -печать + 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.
Часто задаваемые вопросы
- I need to make transparent parts—what casting material should I use?
Opt for ПММА or transparent PC. PMMA has a higher 透光率 (92% против. PC’s 88%) and is cheaper (\(25- )30/kg vs. PC’s \(28- )35/kg), making it better for non-heat-exposed parts (НАПРИМЕР., Отображение обложки). 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, пока 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. Выбирать FDA-approved silicone для форм (НАПРИМЕР., Dow Corning 734) and food-safe casting resins (НАПРИМЕР., food-grade PP or silicone rubber). Avoid materials like PVC (not food-safe) and always ask for certification to ensure compliance with safety standards.
