Silicones for mold-flipping (also called mold-turning silicones) are specialized rubber materials designed to create reusable molds for replicating prototypes—from art crafts to industrial parts. Their flexibility, detail-retaining ability, and adjustable curing properties make them indispensable for small-batch production and product development. This article breaks down the main types of mold-flipping silicones, their core characteristics, сценарии применения, and selection tips—with clear comparisons and practical examples to help you choose the right silicone for your project.
1. Classification by Curing Method: Match to Your Workflow
Curing method directly impacts production efficiency and equipment needs. Mold-flipping silicones are primarily divided into two categories based on how they harden:
| Силиконовый тип | Основные характеристики | Curing Parameters | Идеальные приложения |
| Room-Temperature Curing (РТВ) Силикон | – No heating equipment required; easy to operate for beginners.- Gentle on temperature-sensitive prototypes (НАПРИМЕР., воск, мыло, or low-heat 3D prints).- Cures slowly (12–24 часа) but with minimal shrinkage (0.5–1%).- Берег твердость: 10–30 (мягкий, flexible for complex part demolding). | – Температура: 20°С–25°С (normal room temperature).- Время: 12–24 часа (varies by thickness: 5mm = 12h; 10mm = 24h).- Влажность: Best at 40%–60% (high humidity prolongs curing). | Small-scale art/crafts (handicrafts, wax statues, plaster models), low-volume prototype replication (НАПРИМЕР., custom keychains), and scenarios without ovens or heat tools. |
| Heating-Curing (HTV) Силикон | – Heating accelerates curing (1–3 часа), cutting production cycles.- Higher mechanical strength: Better wear resistance and tear resistance than RTV.- Adjustable hardness (Shore A 30–50) for industrial needs.- Suitable for repeated mold use (50+ цикл). | – Температура: 60°C–120°C (industrial-grade variants can reach 150°C–200°C).- Время: 1–3 часа (higher temp = faster cure: 120°C = 1h; 60°C = 3h).- Постотверждение: Optional 1-hour bake at 80°C to boost durability. | Industrial mass production (auto parts, electronic device shells like TV back covers), high-frequency mold use (НАПРИМЕР., 100+ toy component replicas), and projects needing fast turnaround. |
Key Comparison Example: A jewelry maker uses RTV silicone to replicate wax pendants—no heat means the delicate wax prototype won’t melt. An auto parts manufacturer, напротив, uses HTV silicone to make molds for 500+ rubber gaskets—heating cuts curing time from 24 часы до 1 час, meeting production deadlines.
2. Classification by Hardness: Balance Flexibility and Strength
Твердость (measured by Shore A scale) determines a silicone’s ability to demold complex parts and withstand wear. Choose based on your prototype’s shape and mold lifespan needs:
| Hardness Grade | Shore A Hardness Range | Core Traits | Ideal Prototype Types |
| Soft-Mold Silicone | 10–20 | – Ультрагибкий; easily peels off parts with undercuts (НАПРИМЕР., Изогнутые края, hollow cavities).- Low tear resistance (best for 10–20 cycles).- Excellent for capturing fine textures (0.05mm details like engravings). | Soft prototypes (воск, мыло, глина), Искусство произведения (sculptures with intricate patterns), and one-time/short-run replicas (НАПРИМЕР., custom cake molds). |
| Medium-Hardness Silicone | 30–40 | – Balanced flexibility and durability; the most versatile grade.- Good tear resistance (20–50 циклов).- Works for both soft and hard prototypes. | General-purpose mold-flipping: plastic/metal prototypes (НАПРИМЕР., phone case models), Запасные части потребительской электроники (кнопки пульта от телевизора), and small-batch functional components. |
| Hard-Mold Silicone | 40–50 | – High strength and wear resistance; suitable for high-pressure casting.- Low flexibility (not for undercut parts).- Long mold life (50+ цикл). | Rigid prototypes (CNC-machined metal/plastic), Промышленные детали (Автомобильные кронштейны), and molds for high-viscosity casting materials (НАПРИМЕР., thick epoxy resin). |
Real-World Scenario: A dental lab uses soft-mold silicone (Берег а 15) to make molds for tooth impressions—its flexibility lets the mold peel off the patient’s gums without damaging the soft tissue. A tool manufacturer uses hard-mold silicone (Берег а 45) for metal wrench prototypes—its strength withstands the pressure of pouring molten metal-alloy replicas.
3. Classification by Special Functions: Meet Niche Needs
Some mold-flipping scenarios require silicones with unique properties (НАПРИМЕР., безопасность пищевых продуктов, Высокотемпературное сопротивление). Below are the most common specialized types:
| Special Silicone Type | Ключевые свойства | Требования к отверждению | Идеальные приложения |
| Food-Grade Silicone | – Нетоксичный, odorless, and compliant with FDA/EU food safety standards (НАПРИМЕР., FDA 21 CFR 177.2600).- Resistant to food acids, масла, and repeated washing.- Available in RTV (Shore A 20–30) for easy demolding. | – Same as standard RTV: 20°С–25°С, 12–24 hours.- No post-cure needed; ready to use after demolding. | Food-contact molds: baking pans (cake, bread), шоколадные формы, candy molds, and ice cube trays. |
| High-Temperature Resistant Silicone | – Withstands long-term use at 200°C–300°C (short-term up to 350°C).- Heat-curing (HTV) base with added heat-stabilizing additives.- Низкое тепловое расширение (no mold deformation under high heat). | – Curing temp: 80°C–120°C; время: 2–3 часа.- Post-cure at 150°C for 1 hour to activate heat resistance. | High-temperature casting: Автомобильные детали двигателя (heat-resistant gaskets), аэрокосмические компоненты, and molds for metal-alloy replicas (low-melting tin-lead alloys). |
| Transparent Silicone | – High light transmittance (85%–95%); lets you monitor casting material flow. – Available in RTV/HTV and all hardness grades.- Captures clear details (ideal for optical prototypes). | – Same as matching RTV/HTV types (НАПРИМЕР., transparent RTV = 20°C–25°C, 12–24h).- Requires dust-free mixing to maintain transparency. | Optical models (lens prototypes), crystal crafts, and molds where internal defects need visual inspection (НАПРИМЕР., Медицинские оболочки). |
Критический совет: For food-grade or medical applications, never use standard silicones—they may contain toxic additives that leach into food or come into contact with skin. Always verify compliance with safety standards before use.
4. Key Tips for Selecting Mold-Flipping Silicones
Choosing the right silicone avoids rework, reduces costs, and ensures mold quality. Следуйте этим четырем шагам:
Шаг 1: Analyze the Prototype Material
- Soft prototypes (воск, мыло, глина): Choose soft-mold RTV silicone (Shore A 10–20) to avoid damaging the prototype during demolding.
- Hard prototypes (металл, пластик, Запчасти с ЧПУ): Opt for medium/hard HTV silicone (Shore A 30–50) for durability—hard prototypes won’t deform, so flexibility is less critical.
Шаг 2: Define Production Volume & Cycle Needs
- 1–20 cycles (one-time/short-run): RTV silicone (более низкая стоимость, no heat tools).
- 20–100 cycles (маленькая партия): Medium-hardness HTV silicone (balances cost and lifespan).
- 100+ цикл (Большое объем): Hard-mold HTV or high-temperature silicone (maximizes mold reuse).
Шаг 3: Consider Operating Conditions
- No heating equipment: RTV silicone (room-temperature cure only).
- With ovens/heat tools: HTV silicone (более быстрое лекарство, Лучшая производительность).
- Food/medical use: Food-grade/medical-grade RTV silicone (safety compliance first).
Шаг 4: Test Before Full-Scale Use
Always make a small test mold (НАПРИМЕР., a 5cm × 5cm section of the prototype) before mixing large quantities of silicone. This checks:
- Whether the silicone captures all details.
- Если расформовка проходит гладко (no sticking or tearing).
- If the cured silicone meets hardness/strength needs.
5. Yigu Technology’s Perspective on Mold-Flipping Silicones
В Yigu Technology, мы нашли это 70% of mold-flipping failures come from mismatched silicone types—e.g., using hard silicone for undercut parts or standard silicone for food molds. Our key advice is: prioritize prototype and end-use needs over cost. Например, a client once used standard RTV silicone for chocolate molds, leading to food contamination—switching to food-grade silicone solved the issue and avoided regulatory fines. For industrial clients making auto parts, we recommend medium-hardness HTV silicone (Берег а 35)—it handles 50+ cycles while retaining detail for rubber gasket replicas. We also emphasize vacuum degassing for all silicones (especially HTV)—this eliminates 95% of bubbles that cause mold defects. Mold-flipping silicones are tools for precision; choosing the right one ensures your replicas match the prototype exactly, saving time and rework.
6. Часто задаваемые вопросы: Common Questions About Mold-Flipping Silicones
1 квартал: Can I use RTV silicone for high-temperature casting (НАПРИМЕР., 150° C.)?
А1: No—standard RTV silicone only withstands up to 100°C. High-temperature casting requires specialized high-temperature HTV silicone (200°C–300°C resistance). Using RTV for 150°C applications will cause the mold to melt, деформация, or release toxic fumes.
2 квартал: My soft-mold silicone tears easily during demolding—how to fix this?
А2: Tearing usually stems from using too soft a silicone (Берег а <15) or demolding too quickly. Исправляет: (1) Switch to medium-soft silicone (Shore A 20–25) for better tear resistance. (2) Demold slowly, pulling the silicone at a 45° angle instead of straight up—this distributes force evenly. (3) Apply a thin layer of silicone oil to the prototype before pouring silicone—reduces friction.
Q3: How long can unused mold-flipping silicone be stored?
А3: Unopened, one-component RTV silicone lasts 6–12 months (stored in a cool, dry place away from sunlight). Two-component silicone (база + лечительный агент) has a 12–24 month shelf life for unopened components—once mixed, it must be used within 2–4 hours (varies by brand) before it starts curing. Always check the manufacturer’s label for expiration dates.