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. Der Prozess basiert auf drei Kernmaterialtypen: Prototypenmaterialien (um die Mastervorlage zu erstellen), Formmaterialien (um die flexible Silikonform herzustellen), Und Gussmaterialien (um die endgültigen Teile herzustellen). Unten, we break down each category with clear data, Anwendungsfälle, and tips to help you pick the perfect materials for your needs.
1. Prototype Materials: Der “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 | Gemeinsame Materialien | Schlüsseleigenschaften | Am besten für | Performance Data |
| CNC-Bearbeitung | ABS, Aluminium, Edelstahl | Hohe Präzision, glatte Oberfläche | Prototypes needing tight tolerances (z.B., Getriebe, mechanische Teile) | Toleranzen: ±0,01 mm; Oberflächenbeschaffenheit: Ra 0.2–0.8μm |
| SLA 3D Printing | Photopolymer Resins (z.B., Formlabs Grey Resin) | Complex shape capability, fine detail capture | Intricate designs (z.B., strukturierte Handyhüllen, small medical device components) | Oberflächenbeschaffenheit: 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, SLA 3D printing 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) Silikon—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 | Schlüsseleigenschaften | Mold Life (Verwendungsmöglichkeiten) | Shrinkage Rate | Kosten (Pro kg) | Am besten für |
| Addition-Cure Silicone | Low shrinkage, hohe Haltbarkeit, no odor | 20–50 | 0.1–0.3% | \(25–)40 | High-volume low runs (30–50 Teile) or complex prototypes (z.B., parts with undercuts) |
| Condensation-Cure Silicone | Lower cost, faster cure, slight odor | 10–20 | 0.5–1.0% | \(15–)25 | Small runs (10–20 parts) or simple shapes (z.B., basic housings) |
Why this matters: 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. Zum Beispiel, 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: Der “Final Part” Materialien
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) Materialien, each tailored to specific performance needs:
| Casting Material Type | Specific Materials | Schlüsseleigenschaften | Typische Anwendungen | Performance Highlights |
| Thermoplastic-Like Resins | ABS, PC, PP, PA, PMMA | Mimic production plastics; good strength/durability | Unterhaltungselektronik (Handyhüllen), automotive accessories (Knöpfe), household goods (container lids) | – ABS: Schlagfestigkeit 20 kj /- PC: Heat resistance up to 120°C; 透光率 (Lichtdurchlässigkeit) 88%- PMMA: 透光率 92% (close to glass); kratzfest |
| Flexible Materialien | Gummi, Soft PU Resins | Elastizität, Griff, Stoßdämpfung | Griffe (Fernbedienungen), Siegel (Wasserflaschen), O-Ringe (Rohre) | Shore hardness: A 30–60; Elastic recovery rate >90% |
| High-Temperature Resistant Materials | PPS, PEI, Silicone Rubbers | Withstand extreme heat (150–250°C) | Motorkomponenten, industrial sensors, high-heat tools | – PPS: Heat resistance 220°C- PEI: 250°C; chemical resistance to oils/solvents |
| Spezialmaterialien | PVC, Conductive Resins | Customizable hardness (PVC); electrical conductivity (conductive resins) | Kabelisolierung (PVC), elektronische Steckverbinder (conductive resins) | – PVC: Hardness range Shore A 60–D 80- Conductive resins: Resistivity <10⁻³ Ω·cm |
Cost note: Thermoplastic-like resins (z.B., ABS, PC) kosten \(18–)30 pro kg, while high-temperature materials (z.B., PEI) can cost \(50–)80 pro 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
Bei so vielen Möglichkeiten, Es ist leicht, sich überfordert zu fühlen. Use these 5 factors to narrow down your choices—they’ll help you balance performance, kosten, und Benutzerfreundlichkeit:
- Funktionale Bedürfnisse: If your part needs to be transparent (z.B., a lens), wählen PMMA or transparent PC. If it needs to handle heat (z.B., a coffee maker part), go for PPS or PEI.
- Batch Size: Für 30+ Teile, verwenden addition-cure silicone (longer mold life) to avoid re-making molds. For 10–20 parts, condensation-cure silicone saves money.
- Prototype Complexity: Intricate designs (z.B., tiny text) need SLA 3D printing with photopolymer resin—CNC machining can’t capture ultra-fine details.
- Kosten: If you’re testing a new design, start with cheaper materials (z.B., condensation-cure silicone + PP resin) before upgrading to higher-cost options.
- Processing Ease: Flexible Teile (z.B., Griffe) are easier to cast with soft PU resins—they demold faster than rigid materials and don’t crack the silicone mold.
Die Perspektive von Yigu Technology
Bei 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 (Präzision + Haltbarkeit) and rigid PC/PA casting resins (mimic production parts). For complex, dekorative Teile, SLA 3D printing + 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.
FAQ
- I need to make transparent parts—what casting material should I use?
Entscheiden Sie sich für PMMA or transparent PC. PMMA has a higher 透光率 (92% vs. PCs 88%) and is cheaper (\(25–)30/kg vs. PCs \(28–)35/kg), making it better for non-heat-exposed parts (z.B., Displayabdeckungen). If the part needs to handle mild heat (bis 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, während condensation-cure lasts 10–20. Factors like casting material (abrasive resins wear molds faster) and demolding care (pulling parts gently vs. reißend) 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. Wählen FDA-approved silicone für Formen (z.B., Dow Corning 734) and food-safe casting resins (z.B., food-grade PP or silicone rubber). Avoid materials like PVC (not food-safe) and always ask for certification to ensure compliance with safety standards.