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), و casting materials (to produce the final parts). أقل, 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: ال “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 | مواد مشتركة | الخصائص الرئيسية | الأفضل ل | Performance Data |
| تصنيع CNC | القيمة المطلقة, الألومنيوم, الفولاذ المقاوم للصدأ | دقة عالية, smooth surface finish | Prototypes needing tight tolerances (على سبيل المثال, التروس, الأجزاء الميكانيكية) | التسامح: ±0.01mm; الانتهاء من السطح: Ra 0.2–0.8μm |
| SLA 3D Printing | Photopolymer Resins (على سبيل المثال, Formlabs Grey Resin) | Complex shape capability, fine detail capture | Intricate designs (على سبيل المثال, textured phone cases, small medical device components) | الانتهاء من السطح: Ra 0.1–0.3μm; Detail resolution: 0.025مم |
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 الطباعة is the way to go, as it can replicate details as small as a grain of sand.
2. مواد العفن: Flexible Silicone for Replicating Details
The mold material in silicone vacuum casting is almost always RTV (Room Temperature Vulcanization) السيليكون—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 | الخصائص الرئيسية | Mold Life (Uses) | Shrinkage Rate | يكلف (لكل كجم) | الأفضل ل |
| Addition-Cure Silicone | Low shrinkage, high durability, no odor | 20–50 | 0.1–0.3% | \(25- )40 | High-volume low runs (30-50 أجزاء) or complex prototypes (على سبيل المثال, قطع الغيار مع الأسف) |
| Condensation-Cure Silicone | Lower cost, faster cure, slight odor | 10–20 | 0.5–1.0% | \(15- )25 | أشواط صغيرة (10-20 أجزاء) or simple shapes (على سبيل المثال, basic housings) |
لماذا هذا يهم: 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. على سبيل المثال, 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: ال “Final Part” مواد
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) مواد, each tailored to specific performance needs:
| Casting Material Type | Specific Materials | الخصائص الرئيسية | التطبيقات النموذجية | Performance Highlights |
| Thermoplastic-Like Resins | القيمة المطلقة, الكمبيوتر الشخصي, ص, السلطة الفلسطينية, PMMA | Mimic production plastics; good strength/durability | Consumer electronics (حالات الهاتف), automotive accessories (المقابض), household goods (container lids) | – القيمة المطلقة: Impact strength 20 kj /- الكمبيوتر الشخصي: Heat resistance up to 120°C; 透光率 (انتقال الضوء) 88%- PMMA: 透光率 92% (close to glass); مقاوم للخدش |
| Flexible Materials | ممحاة, Soft PU Resins | Elasticity, grip, shock absorption | قبضة (عناصر التحكم عن بُعد), الأختام (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 درجة مئوية) | مكونات المحرك, industrial sensors, high-heat tools | – PPS: Heat resistance 220°C- PEI: 250درجة مئوية; chemical resistance to oils/solvents |
| مواد متخصصة | PVC, Conductive Resins | Customizable hardness (PVC); electrical conductivity (conductive resins) | Cable insulation (PVC), electronic connectors (conductive resins) | – PVC: Hardness range Shore A 60–D 80- Conductive resins: Resistivity <10⁻³ Ω·cm |
Cost note: Thermoplastic-like resins (على سبيل المثال, القيمة المطلقة, الكمبيوتر الشخصي) يكلف \(18- )30 لكل كجم, while high-temperature materials (على سبيل المثال, PEI) can cost \(50- )80 لكل كجم. 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, يكلف, and usability:
- Functional Needs: If your part needs to be transparent (على سبيل المثال, a lens), pick PMMA or transparent PC. If it needs to handle heat (على سبيل المثال, a coffee maker part), go for PPS or PEI.
- حجم الدُفعة: ل 30+ أجزاء, يستخدم addition-cure silicone (longer mold life) to avoid re-making molds. For 10–20 parts, condensation-cure silicone saves money.
- Prototype Complexity: Intricate designs (على سبيل المثال, tiny text) need SLA 3D الطباعة with photopolymer resin—CNC machining can’t capture ultra-fine details.
- يكلف: If you’re testing a new design, start with cheaper materials (على سبيل المثال, condensation-cure silicone + PP resin) before upgrading to higher-cost options.
- Processing Ease: أجزاء مرنة (على سبيل المثال, قبضة) are easier to cast with soft PU resins—they demold faster than rigid materials and don’t crack the silicone mold.
منظور Yigu Technology
في 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 (دقة + متانة) and rigid PC/PA casting resins (mimic production parts). For complex, أجزاء زخرفية, SLA 3D الطباعة + 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.
التعليمات
- 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% مقابل. PC’s 88%) and is cheaper (\(25- )30/kg vs. PC’s \(28- )35/kg), making it better for non-heat-exposed parts (على سبيل المثال, أغطية العرض). 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, بينما 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. يختار FDA-approved silicone للقوالب (على سبيل المثال, Dow Corning 734) and food-safe casting resins (على سبيل المثال, food-grade PP or silicone rubber). Avoid materials like PVC (not food-safe) and always ask for certification to ensure compliance with safety standards.
