Silicone molding technology is a manufacturing process that transforms liquid silicone rubber (LSR) ou compostos de silicone sólido em produtos moldados com precisão por meio de cura controlada. Ele aproveita a elasticidade única do silicone, resistência ao calor, e biocompatibilidade para atender indústrias desde proteção de relíquias culturais até dispositivos médicos. Mas o que torna esta tecnologia versátil, how do you select the right methods for specific needs, and how to avoid common production pitfalls?
1. Core Types of Silicone Molding Technology: A Comparative Analysis
Silicone molding technology varies by material state and curing mechanism. The table below breaks down key types, seus pontos fortes, e usos ideais:
| Tipo de tecnologia | Key Characteristics | Vantagens | Limitações | Ideal Application Scenarios |
| Liquid Silicone Rubber (LSR) Moldagem | Uses two-component LSR (mixed 1:1 ou 10:1); cures at 120–180°C | Alta precisão (±0,01 mm); no by-products; fast cycle time (30–60s/part) | High equipment cost; requires specialized injection machines | Dispositivos médicos (por exemplo, componentes protéticos), produtos para bebês (por exemplo, pacifier nipples) |
| Solid Silicone Compression Molding | Uses pre-cut solid silicone sheets; pressed in molds (160–200ºC, 10–20MPa) | Low equipment investment; suitable for large parts; fácil de escalar | Longer curing time (5–10min/part); lower detail resolution | Selos industriais, juntas automotivas, large craft molds |
| Silicone Coating & Dipping | Applies thin silicone layers via brushing/dipping; cures at room temp or low heat | Espessura uniforme (5–500μm); adheres to diverse substrates (metal, fabric) | Limited to thin-walled products; slow for thick layers | Electronic component waterproofing, cultural relic protective coatings |
| Vacuum-Assisted Silicone Molding | Uses vacuum chambers to eliminate bubbles during pouring; for LSR or solid compounds | No bubble defects; high surface finish (Ra≤1.6μm) | Longer process time; requires vacuum equipment | Precision jewelry molds, componentes ópticos, cultural relic replication |
2. Material Selection for Silicone Molding: Match to Performance Needs
The success of silicone molding depends on choosing the right silicone type. Below is a guide to material categories and their key parameters:
UM. Silicone Material Categories
| Categoria de materiais | Principais recursos | Compliance Standards | Typical Use Cases |
| Condensation-Cure Silicone | Releases ethanol during curing; baixo custo; easy to operate | Nível industrial (no food/medical compliance) | Ordinary crafts, non-critical seals |
| Addition-Cure Silicone | No by-products; baixo encolhimento (<0.1%); high purity | FDA/ISO 10993 (médico); FDA 21 CFR (comida) | Medical prosthetics, food-contact molds (por exemplo, chocolate molds) |
| Fluorosilicone | Heat resistance up to 300°C; resistência química (ácidos, óleos) | MIL-STD-883 (aeroespacial); ASTM D2000 (automotivo) | Selos aeroespaciais, high-temperature industrial gaskets |
B. Critical Material Parameters to Consider
- Dureza (Costa A):
- 5–10°: Ultra-soft (cultural relic cushions, medical skin contact parts)
- 20–30°: Médio-macio (resin craft molds, baby product components)
- 40–60°: Duro (selos industriais, juntas automotivas)
- Viscosity:
- Baixo (<5,000 cP): Flows into micro-details (jewelry molds, electronic component coatings)
- Alto (>10,000 cP): Ideal for brushing/dipping (thick protective layers for cultural relics)
- Tear Strength:
4kN/m: High-durability needs (reusable molds, frequent-use seals)
- 2–3kN/m: Budget-friendly, low-cycle products (disposable craft molds)
3. Standardized Workflow of Silicone Molding Technology
A typical silicone molding process follows 5 etapas principais, with strict controls at each step to ensure quality:
Stage 1: Pre-Production Preparation
- Protótipo & Projeto de molde:
- For uneven substrates (madeira, pedra), spray PVA water-soluble release agent to prevent silicone adhesion.
- Add chamfers (0.5–1 mm) to mold edges to avoid stress concentration and tearing.
- For deep-hole structures, embed magnetic nuts for post-molding positioning.
- Configuração de ferramentas:
- Build a containment frame (glass/acrylic) 10cm taller than the prototype’s highest point to prevent overflow.
- Reserve a glue injection port (diameter ≥1cm) and serpentine exhaust grooves to release air.
Stage 2: Preparação de Materiais & Mixing
- Component Mixing:
- For LSR: Use an electronic scale to weigh AB components (por exemplo, 1:1 ratio) with ±0.1g accuracy.
- For solid silicone: Cut compounds into blanks matching the mold’s cavity volume (add 5–10% for compression shrinkage).
- Defoaming:
- Place mixed LSR in a vacuum chamber (-0.1MPa) for 15–20 minutes; repeat 2–3 times at 5-minute intervals for bubble-free results.
Stage 3: Moldagem & Cura
| Tipo de tecnologia | Molding Process | Curing Parameters |
| LSR Molding | Inject mixed LSR into heated molds (120–150ºC) via specialized injection machines | Cure time: 30–60s; pressão: 5–10MPa |
| Moldagem por compressão | Place solid silicone blanks in molds; apply pressure (10–20MPa) e calor (160–180ºC) | Cure time: 5–10min; post-cure at 200°C for 2h to eliminate stress |
| Coating/Dipping | Brush/dip substrate in silicone; let stand for 10–15min to level | Room-temperature cure: 24h; low-heat cure: 60°C for 2h |
Stage 4: Desmoldagem & Pós-processamento
- Desmoldagem:
- Use thin plastic sheets to separate silicone from molds; tap the back gently to vibrate stuck parts.
- For complex molds, pre-cut guide grooves (depth ≤1/3 of mold thickness) to ease peeling.
- Aparar & Acabamento:
- Cut excess flash with sharp scissors; sand inner surfaces with 400–600 grit sandpaper for Ra≤1.6μm smoothness.
Stage 5: Inspeção de Qualidade
- Estabilidade Dimensional: Measure key dimensions 3 times with a caliper; ensure tolerance within ±0.5%.
- Qualidade de Superfície: Use a roughness meter to verify Ra≤1.6μm; check for pockmarks or bubbles.
- Performance Testing: For high-cycle products, run dynamic fatigue tests (≥100,000 folds without tearing).
4. Troubleshooting Common Issues in Silicone Molding
Even with precise controls, issues may arise. Below is a cause-and-solution guide for frequent problems:
| Problem Phenomenon | Root Cause | Practical Solution |
| Surface Pockmarks/Imperfections | Substrate contamination (oil/dust); environmental dust adhesion | – Clean prototypes with alcohol; operate in a dust-free workshop.- Apply a thin release agent layer to smooth uneven surfaces. |
| Uneven Thickness | Turbulence from fast pouring; mold cavity design flaws | – Use a funnel for slow, layered pouring (1–2cm/min).- Optimize mold vents to balance pressure distribution. |
| Bubble Trapping | Inadequate vacuum defoaming; mixing too vigorously | – Extend vacuum time to 20–25min; add a second defoaming cycle.- Stir silicone at 30–50 RPM (avoids air entrapment). |
| Edge Curl | Uneven curing shrinkage; high exotherm during molding | – Switch to low-temperature curing (reduce by 10–15°C).- Add a 2-hour post-cure at 60°C to relieve internal stress. |
| Short Service Life | Resin/chemical residue corrosion; UV aging | – Clean molds with steam + neutral detergent after each use.- Store molds in opaque containers (avoids UV exposure); apply talcum powder for long-term storage. |
5. Industry-Specific Applications of Silicone Molding Technology
Silicone molding technology solves unique challenges across sectors. Here are key use cases with implementation details:
| Indústria | Application Case | Molding Technology Used | Key Innovations |
| Cultural Relic Protection | Fragile relic support & shape replication | Vacuum-assisted LSR molding (5° Shore A ultra-soft silicone) | Embedded optical fiber sensors to monitor relic stress in real time; glass fiber reinforced layer for durability |
| Dispositivos Médicos | Custom orthotic insoles | Addition-cure LSR molding (biocompatible grade) | 3D-scanned prototypes for personalized fit; post-cure at 120°C to meet ISO 10993 padrões de biocompatibilidade |
| Toy Manufacturing | Limited-edition doll molds (multi-color parts) | Modular compression molding (colored silicone) | Separate head/body molds with magnetic positioning; colored silicone for easy part identification |
| Eletrônica | Circuit board waterproofing | Silicone coating (low-viscosity LSR) | Uniform 20μm coating; cures at 80°C to avoid damaging electronic components |
6. Yigu Technology’s Perspective on Silicone Molding Technology
Na tecnologia Yigu, we see silicone molding technology as a bridge between precision engineering and creative needs. For cultural relic protection projects, our vacuum-assisted LSR molding (5° Shore A silicone) has successfully replicated 200+ fragile artifacts, with 0.1mm detail accuracy and real-time stress monitoring. Para clientes médicos, our addition-cure LSR molding process meets FDA 21 CFR standards, delivering custom prosthetic components with <0.01mm dimensional tolerance.
We’re advancing two key innovations: 1) Developing eco-friendly LSR (reducing VOCs by 35%) for sustainable manufacturing; 2) Integrating AI into mold temperature control (optimizing curing time by 20% while maintaining quality). Our goal is to make silicone molding technology more accessible, eficiente, and tailored to industry-specific challenges.
Perguntas frequentes
- What’s the difference between LSR molding and solid silicone compression molding for medical products?
LSR molding is ideal for high-precision, small medical parts (por exemplo, pontas de cateter) due to its ±0.01mm tolerance and biocompatibility (no by-products). Solid silicone compression molding works for larger parts (por exemplo, orthotic braces) and has lower equipment costs but longer cycle times. Always choose addition-cure LSR for implantable/skin-contact medical products.
- How to extend the service life of silicone molds made via this technology?
Clean molds with steam + neutral detergent (avoid sharp tools) after each use; store in opaque, dry containers (prevents UV aging); apply a thin talcum powder layer for storage over 1 mês. For high-frequency use, add a 2-hour post-cure at 60°C every 50 cycles to refresh elasticity.
- Can silicone molding technology be used for high-temperature industrial parts (por exemplo, 250°C+)?
Yes—use fluorosilicone material (heat resistance up to 300°C) with compression molding (180–200°C cure). Ensure a 4-hour post-cure at 220°C to enhance heat resistance. This setup is suitable for aerospace seals and high-temperature industrial gaskets, meeting MIL-STD-883 standards.