Силиконовый вакуумный кастинг is a high-precision manufacturing process used to replicate complex parts—from electronic device shells to art prototypes—by eliminating air bubbles via vacuum pressure. The success of this process depends entirely on selecting the right materials, which include silicone molds, base prototypes, auxiliary agents, and casting resins. This article breaks down each material category with clear comparisons, technical specs, и реальные приложения, helping you optimize vacuum casting for accuracy, долговечность, и экономическая эффективность.
1. Core Silicone Mold Materials: The Foundation of Casting
Silicone is the heart of vacuum casting molds—its flexibility and detail-retaining ability ensure replicas match the original prototype. Materials are categorized by curing mechanism and performance, each suited to specific needs.
| Силиконовый тип | Ключевые характеристики | Curing Parameters | Идеальные приложения |
| Condensation Silicone | – Releases small molecules (ethanol/acetic acid) during curing.- Бюджетный (30–50% cheaper than additive silicone).- Moderate shrinkage (2–3%), which may blur fine details.- Берег твердость: 20–40 (мягкий, Легко демольд). | – Mixing ratio: 100:2–5 (силикон:лечительный агент).- Время лечения: 4–8 часов (20°С–25°С).- No vacuum needed for mixing (but vacuum casting still requires bubble removal). | Simple parts with low precision demands: handicrafts, игрушечные прототипы, and non-critical decorative items (НАПРИМЕР., пластиковые горшки для растений). |
| Добавка (Platinum-Cure) Силикон | – No small molecule release during curing.- Ultra-low shrinkage (0.1–0,5%)—critical for high-precision parts.- High durability (reusable 40–60 cycles, против. 20–30 for condensation).- Берег твердость: 30–60 (versatile for soft/hard parts). | – Mixing ratio: 1:1 (by volume/weight—easy to measure).- Время лечения: 2–4 часа (20°С–25°С; 1 hour at 50°C–60°C).- Requires vacuum defoaming (1–2 minutes at -0.1МПА) to avoid internal bubbles. | High-precision components: Электронные оболочки устройства (TV remote casings), Запчасти медицинского устройства (syringe nozzles), and automotive interior trim (кнопки панели панели). |
| High-Temperature Resistant Silicone | – Withstands post-casting heat (200° C - 300 ° C.) for heat-curing resins.- Retains flexibility and shape at extreme temperatures.- Низкая усадка (0.3–0,8%) and high tear resistance. | – Mixing ratio: 100:5 (силикон:лечительный агент).- Время лечения: 6–10 часов (20°С–25°С; 2–3 hours at 80°C).- Must be cured in a temperature-controlled oven to activate heat resistance. | High-heat casting scenarios: metal alloy replicas (low-melting tin-lead alloys), thermoset resin parts (epoxy cured at 120°C), and aerospace component prototypes. |
| Transparent Silicone | – High light transmittance (85–95% after curing)—lets you monitor casting material flow.- Available in both condensation and additive types (additive preferred for precision).- Similar mechanical properties to non-transparent counterparts. | – Same curing parameters as matching non-transparent silicone (НАПРИМЕР., 1:1 ratio for additive transparent).- Requires extra care to avoid dust (which reduces transparency). | Оптические компоненты: light diffusers, transparent device housings (НАПРИМЕР., Крышки светодиодных ламп), and prototypes where internal casting defects need visual inspection. |
2. Base Prototype Materials: The “Original Model”
The prototype (or master model) defines the shape of the final replica. It must be durable enough to withstand silicone pouring and compatible with silicone (no chemical reactions).
| Прототип материал | Ключевые черты | Compatibility with Silicone | Идеально подходит для |
| 3D-Printed Resins (SLA/DLP) | – Высокая точность (± 0,05 мм) for complex details.- Гладкая поверхность (RA 0,8–1,6 мкм) reduces sanding time.- Available in rigid or flexible variants. | Отличный (no reaction with silicone). Use a light release agent (Силиконовое масло) for easy demolding. | Rapid prototyping of intricate parts: jewelry patterns, electronic connector prototypes, and TV interface panels. |
| CNC-Machined Metals (Алюминий/латунь) | – Ультра-прочный (reusable for 100+ mold makings).- High surface finish (Ra 0.4–0.8μm) for mirror-like replicas.- Теплостойкий (suitable for high-temperature silicone). | Хороший. Use petroleum jelly or specialized metal release spray to prevent silicone sticking. | Industrial-grade masters: automotive part prototypes (корпусы передачи), mold inserts for repeated use, и высокие компоненты. |
| CNC-Machined Resins/Wax | – Lower cost than metal.- Легко в машине (faster turnaround than metal).- Wax is ideal for low-temperature casting (melts away if needed). | Очень хороший. Wax requires petroleum jelly (alcohol dissolves wax); resin uses standard release agents. | Art prototypes: sculptural replicas, custom candle molds, and low-volume decorative parts (НАПРИМЕР., ceramic vase masters). |
| Existing Finished Parts | – No need to design a new prototype (экономит время).- Must be clean and undamaged (scratches transfer to the mold). | Depends on the part material: plastic/metal works; rubber may react with condensation silicone. | Reverse-engineering projects: copying legacy parts (old TV knobs), replacement components for out-of-production equipment, and competitor product analysis. |
3. Auxiliary Materials: Ensure Process Smoothness & Mold Performance
These materials enhance mold durability, prevent defects, and optimize casting results—they’re often overlooked but critical for success.
| Auxiliary Material | Цель | Usage Tips |
| Агенты высвобождения плесени | Create a barrier between silicone and the prototype/replica to avoid sticking. | – Petroleum Jelly: For wax prototypes (бюджетный, легко нанести).- Silicone Oil (100–500 cSt): For plastic/metal prototypes (никаких остатков, won’t blur details).- Specialized Spray: For silicone-on-silicone casting (prevents chemical bonding).- Нанесите тонкий, even layer—thick coats distort details. |
| Подкрепляющие материалы | Boost mold strength and wear resistance (prevents tearing during demolding). | – Fiberglass Cloth: Lay 1–2 layers over the silicone surface (after pouring, before curing) for large molds (НАПРИМЕР., TV back cover molds).- Silicone Fillers (Silica Powder): Mix 5–10% into silicone to increase hardness (Shore A +5–10) Для частей с высоким содержанием. |
| Curing Agents/Catalysts | Control silicone curing speed and final properties. | – Condensation Catalysts: Use 2–5% (more = faster cure, but may reduce flexibility).- Platinum Catalysts: 1:1 соотношение (fixed—cannot adjust cure speed without changing temperature).- Store in cool, dry places (heat deactivates platinum catalysts). |
| Sealants/Tapes | Prevent silicone leakage from the mold frame during pouring. | – Acrylic Sealant: For permanent frame seals (wood/metal frames).- Masking Tape: For temporary seals (plastic frames, easy to remove).- Apply 2–3 layers along frame edges to fill gaps. |
4. Кастинговые материалы: The “Replica” Materials
After the silicone mold is made, these materials are poured (под вакуумом) to create the final part. They’re chosen based on strength, Гибкость, and end-use.
| Литейный материал | Ключевые свойства | Vacuum Casting Parameters | Приложения |
| Полиуретан (Пута) Смола | – Быстрое отверждение (1–2 hours at 20°C–25°C; 30 минуты при 60 ° C.).- Бюджетный ($20–40 per kg).- Универсальный: жесткий (Шор Д 60–80) или гибкий (Shore A 30–50).- Хорошее воздействие сопротивления (10-14 кДж /). | – Вакуумное давление: -0.095 к -0.1МПА (Удаляет пузырьки).- Pouring temperature: 25°C–30°C (too hot = flash curing). | Мелкосерийные функциональные детали: кнопки пульта от телевизора, phone case replicas, and toy components. |
| Эпоксидная смола | – Высокая сила (предел прочности: 50–80 МПа, против. PU’s 30–50 MPa).- Теплостойкий (120°C–180°C после отверждения).- Низкая усадка (0.5–1%)—good for structural parts. | – Вакуумное давление: -0.1МПА (hold for 2–3 minutes to remove deep bubbles).- Время лечения: 4–6 часов (20°С–25°С; 1–2 hours at 80°C). | Структурные компоненты: Автомобильные кронштейны, electronic device housings (laptop bases), and medical tool handles. |
| Low-Melting Alloys (Tin-Lead/Bismuth) | – Точка плавления: 183°C–250°C (compatible with high-temperature silicone).- Metallic finish (Не требуется картина).- Высокая плотность (feels like real metal). | – Вакуумное давление: -0.1МПА (critical—metal bubbles cause cracks).- Pouring temperature: 20°C–30°C above melting point (avoids premature solidification). | Metal replicas: декоративное оборудование (Дверные ручки), scale model parts (miniature car bodies), and jewelry (metal pendants). |
| Gypsum/Plaster | – Ультра-низкая стоимость ($5–10 per kg).- Легко раскрасить (mix pigments before pouring).- Хрупкий (low impact resistance—not for functional parts). | – Вакуумное давление: -0.08 к -0.09МПА (too high = sucks out fine particles).- Время лечения: 24–48 часов (air-dry; no oven needed). | Art/teaching models: sculptural replicas, Анатомические модели (skull casts), and classroom demonstrations. |
5. Yigu Technology’s Perspective on Silicone Vacuum Casting Materials
В Yigu Technology, we’ve found that material mismatches cause 70% of vacuum casting failures—e.g., using condensation silicone for high-precision TV prototypes or low-temperature silicone for metal casting. Our key advice is: prioritize silicone type based on precision and end-use. For clients making electronic device shells (НАПРИМЕР., корпуса умных часов), we always recommend additive silicone—it eliminates shrinkage-related defects, сохранение 30% в переработке затрат. For budget-sensitive projects (НАПРИМЕР., craft replicas), condensation silicone works but requires extra sanding to fix detail blurring. We also emphasize testing material compatibility: a client once used a rubber prototype with condensation silicone, causing the rubber to degrade—switching to a 3D-printed resin prototype solved the issue. Окончательно, don’t skip reinforcement for large molds: fiberglass-clad silicone molds last 2x longer than unreinforced ones, critical for small-batch production (50+ реплики).
6. Часто задаваемые вопросы: Common Questions About Silicone Vacuum Casting Materials
1 квартал: Can I use condensation silicone for high-precision parts (НАПРИМЕР., electronic connectors with 0.1mm slots)?
А1: No—condensation silicone’s 2–3% shrinkage will close 0.1mm slots or blur fine details. Use additive silicone instead (0.1–0.5% shrinkage) to retain precision. Например, a 0.1mm slot cast with additive silicone will remain 0.095–0.1mm, while condensation silicone will reduce it to 0.07–0.08mm (too small for connectors).
2 квартал: What casting material should I use for a functional TV remote prototype that needs to withstand drops?
А2: Use rigid polyurethane (Пута) смола (Shore D 70–80) or epoxy resin. PU resin offers better impact resistance (15 kJ/m² vs. epoxy’s 10 KJ /), making it ideal for drop-prone parts. Test by dropping the replica from 1m onto a hard surface—PU resin should not crack, while gypsum/plaster will shatter immediately.
Q3: Why does my high-temperature silicone mold still deform when casting low-melting alloy?
А3: This usually stems from two issues: (1) The silicone wasn’t fully cured (insufficient oven time at 80°C—re-cure for 2 Дополнительные часы). (2) The alloy pouring temperature is too high (exceeding the silicone’s service limit—keep it 20°C–30°C above the alloy’s melting point, not higher). Например, a 200°C silicone mold will deform if poured with 300°C alloy—lower the temperature to 270°C (for a 250°C melting point alloy).