Silicone mold injection molding is an advanced manufacturing technology that uses liquid silicone rubber (LSR) as raw material, injecting it into high-precision molds under controlled temperature and pressure to produce high-quality silicone products. Unlike traditional manual mold making, it excels in mass production, высокая точность размеров, and stable product performance—making it a core process in medical, электронный, и автомобильная промышленность. But what are its core principles? How to control key processes? And how to address its unique challenges? This article answers these questions in detail.
1. Основные принципы & Материальные характеристики
To understand silicone mold injection molding, we first break down its working mechanism and the properties of its key raw material—liquid silicone.
А. Основной принцип работы
The process follows a simple but precise 因果链 (cause-and-effect chain):
- Сырье плавление: Liquid silicone (two-component: main agent + лечительный агент) is fed into the injection machine’s barrel, where it is heated to a flowable state (no melting—silicone is thermoset, so this step softens it for injection).
- High-Pressure Injection: The injection machine pushes the softened silicone into a high-precision mold cavity (tolerance ±0.01mm) at a controlled speed (5–20mm/s) и давление (10–50MPa).
- Выклятый & Vulcanization: Плесень нагревается (120–180 ° C.) to trigger a chemical reaction in the silicone, turning it from liquid to elastic solid. Curing time depends on product thickness—e.g., 1mm-thick parts take 10–15 seconds; 10mm-thick parts take 60–90 seconds.
- Демольд & Отделка: После вылечения, плесень открывается, and the product is ejected. Пост-обработка (выслушивание, обрезка) removes excess material, resulting in a finished part.
Беременный. Ключевой материал: Liquid Silicone Rubber (LSR)
LSR’s unique properties determine the process’s advantages. The table below highlights its critical characteristics:
| Material Characteristic | Specific Performance | Role in Injection Molding |
| Fluidity | Низкая вязкость (5,000–20,000 cP) | Flows into micro-details of the mold (НАПРИМЕР., 0.1mm-thick sealing lips) |
| Теплостойкость | Withstands -60°C to +250°C (short-term +300°C) | Suitable for high-temperature applications (НАПРИМЕР., automotive engine gaskets) |
| Химическая стабильность | Сопротивляется кислотам, щелочи, масла, и растворители | Идеально подходит для медицинских устройств (sterilized with alcohol) and electronic parts (resists coolants) |
| Эластичность | Удлинение при перерыве >500%; Shore hardness 20–80A | Ensures products (НАПРИМЕР., phone buttons, Уплотнительные кольца) maintain flexibility after repeated use |
| Биосовместимость | Medical-grade LSR meets FDA 21 CFR §177.2600 | Safe for skin-contact products (НАПРИМЕР., baby pacifiers, medical catheters) |
2. Step-by-Step Production Process
Silicone mold injection molding follows a standardized, linear workflow—each step requires strict parameter control to avoid defects.
Шаг 1: Подготовка сырья & Тестирование
- Component Mixing: Blend LSR main agent and curing agent in a precise ratio (общий 1:1 или 10:1) using an automated mixer. For colored products, add 1–3% non-toxic pigments to the mixture.
- Качественная проверка: Conduct 3 key tests:
- Viscosity Test: Ensure viscosity is 5,000–15,000 cP (too high = poor flow; too low = leakage).
- Curing Test: Cure a small sample at 160°C for 30 seconds—check for full solidification (no sticky surface).
- Impurity Check: Filter the mixture through a 5μm sieve to remove particles (prevents mold clogging).
Шаг 2: Дизайн плесени & Производство
Molds are the “heart” of the process—their precision directly impacts product quality.
- Соображения дизайна:
- Расположение ворот: Поместите ворота (injection inlets) at thick sections to avoid air traps. Для небольших деталей (НАПРИМЕР., электронные разъемы), use pinpoint gates (0.5–1 -мм диаметр).
- Система охлаждения: Add water channels around the cavity to control mold temperature (±2°C tolerance)—prevents uneven curing.
- Поверхностная обработка: Apply chrome plating (5–10μm thickness) or nitriding to the mold surface. This improves wear resistance (продлевает срок службы формы 100,000+ цикл) and release performance (reduces sticking).
- Manufacturing Equipment: Use CNC machining centers (accuracy ±0.005mm) to mill the mold cavity. Для сложных форм (НАПРИМЕР., Компоненты медицинского устройства), add EDM (Электрическая обработка) for micro-details.
Шаг 3: Injection Molding Parameter Setup
Key parameters must be optimized—incorrect settings cause defects like bubbles or shrinkage. The table below lists critical parameters and their ideal ranges:
| Параметр | Ideal Range | Impact of Incorrect Settings |
| Barrel Temperature | 40–60 ° C. (zone 1: 40° C.; zone 2: 50° C.; zone 3: 60° C.) | Слишком высоко (>70° C.) = premature curing (blocks the barrel); Слишком низко (<30° C.) = poor flow |
| Давление впрыска | 15–30MPa | Слишком высоко (>40МПА) = mold deformation; Слишком низко (<10МПА) = incomplete cavity filling |
| Injection Speed | 8–15mm/s (staged: slow start → fast middle → slow end) | Too fast (>20мм/с) = air trapping (пузырьки); Слишком медленно (<5мм/с) = cold slugs (uneven texture) |
| Температура формы | 140–160 ° C. | Слишком высоко (>180° C.) = over-curing (хрупкие части); Слишком низко (<120° C.) = under-curing (sticky surface) |
| Время лечения | 10–120 секунд (1 second per mm of thickness) | Too short = under-curing; too long = reduced production efficiency |
Шаг 4: Выклятый, Демольд & Пост-обработка
- Выклятый: The mold remains closed for the set time—use a mold temperature controller to maintain stable heat.
- Демольд: Use robotic ejectors (Для массового производства) or manual tools (Для небольших партий) удалить детали. Apply a thin layer of silicone release agent if sticking occurs (avoid excess—causes surface defects).
- Пост-обработка:
- Выслушивание: Trim gate residues with a laser cutter (Для точных частей) or sharp scissors (Для некритических частей).
- Уборка: Wash parts with deionized water to remove release agent residue.
- Secondary Vulcanization (Необязательный): Для высокотемпературных частей (НАПРИМЕР., Автомобильные печати), bake at 200°C for 2–4 hours to improve heat resistance.
3. Преимущества & Проблемы: Сравнительный анализ
Silicone mold injection molding has clear strengths compared to traditional manufacturing methods (НАПРИМЕР., сжатие литья, manual casting). It also faces unique challenges—understanding both helps users decide if it’s the right process.
А. Advantages Over Traditional Methods
| Преимущество | Silicone Mold Injection Molding | Сжатие литья | Manual Casting |
| Эффективность производства | Высокий (30–60 parts per minute for small components) | Середина (5–10 parts per minute) | Низкий (1–2 parts per hour) |
| Точность размеров | ± 0,01 мм (ideal for precision parts) | ± 0,1 мм (limited by mold pressure) | ± 0,5 мм (human error) |
| Product Consistency | 99.5% единообразие (автоматический процесс) | 90% единообразие (Зависит от навыка оператора) | 70% единообразие (high variability) |
| Сложность обработка | Отличный (can produce parts with undercuts, Микро-дыры) | Бедный (requires split molds for complexity) | Очень плохо (limited to simple shapes) |
| Материальные отходы | Низкий (<5% scrap—excess can be recycled) | Середина (10–15% scrap) | Высокий (20–30% scrap) |
Беременный. Ключевые проблемы & Mitigation Strategies
| Испытание | Первопричина | Mitigation Strategy |
| Высокие первоначальные инвестиции | Mold manufacturing (Обработка с ЧПУ + Поверхностная обработка) расходы \(10,000- )100,000; injection machines cost \(50,000- )200,000 | – Для небольших партий: Use shared molds (reduces cost by 50%).- For long-term projects: Choose high-wear-resistant mold materials (НАПРИМЕР., H13 сталь) to extend life (100,000+ цикл) |
| Mold Clogging | Impurities in LSR or low fluidity | – Filter LSR through 5μm sieves before injection.- Preheat LSR to 50°C (improves fluidity) |
| Bubble Formation | Air trapped during injection or incomplete venting | – Add vent grooves (0.01–0.02mm depth) to the mold.- Use vacuum-assisted injection (removes air from the cavity) |
| Shrinkage Defects | Uneven cooling or over-curing | – Optimize mold cooling channels (ensure uniform temperature).- Add 1–2% shrinkage allowance to the mold design |
4. Области применения: Где это сияет
Silicone mold injection molding is widely used in industries that demand precision, долговечность, и биосовместимость. The table below highlights key applications with specific examples:
| Промышленность | Typical Products | LSR Grade | Key Process Requirements |
| Медицинские устройства | Катетерные советы, surgical instrument gaskets, baby pacifiers | Medical-grade (FDA 21 CFR §177.2600) | – Cleanroom production (Сорт 100,000).- No release agent (avoids contamination).- Biocompatibility testing post-production |
| Электроника | Phone buttons, LED lamp seals, sensor O-rings | Промышленное сорта (high insulation) | – Высокая точность (±0.005mm for button travel).- Low volatility (no VOCs to damage electronics) |
| Автомобиль | Engine gaskets, fuel system seals, Компоненты приборной панели | High-temperature grade (resists 250°C) | – Химическая устойчивость (до масла, охлаждающие жидкости).- Vibration resistance (удлинение >500%) |
| Потребительские товары | Silicone kitchen utensils (spatulas), waterproof watch bands | Пищевой (FDA одобрено) | – Non-toxic pigments.- Гладкая поверхность (Раствор <0.8мкм) для легкой уборки |
5. Yigu Technology’s Perspective on Silicone Mold Injection Molding
В Yigu Technology, we see silicone mold injection molding as a cornerstone of high-precision manufacturing—especially for industries like medical and automotive. Для медицинских клиентов, our custom injection molds (Допуск ± 0,008 мм) and medical-grade LSR have enabled the production of 100,000+ catheter tips with 0% biocompatibility failures. For automotive partners, our high-temperature LSR (resists 280°C) and optimized cooling systems reduce engine gasket shrinkage to <0.5%, improving product lifespan by 30%.
We’re addressing key challenges by: 1) Developing low-cost mold materials (НАПРИМЕР., coated aluminum) that cut mold costs by 40% во время поддержания 50,000+ цикл; 2) Integrating AI into parameter control (automatically adjusts temperature/pressure to reduce defects by 25%). Our goal is to make this technology accessible to mid-sized businesses—balancing precision with affordability.
Часто задаваемые вопросы
- Какое минимальное количество заказа (Могил) for silicone mold injection molding?
MOQ depends on mold cost: Для стандартных деталей (НАПРИМЕР., Уплотнительные кольца), MOQ is 10,000–50,000 units (чтобы компенсировать стоимость плесени). Для пользовательских деталей, we offer shared molds with MOQ as low as 1,000 единицы (ideal for small-batch testing).
- Can silicone mold injection molding produce transparent silicone products?
Yes—use high-purity LSR (impurity content <0.1%) and polished molds (Раствор <0.02мкм). We’ve produced transparent medical connectors with 90% легкая коэффициент пропускания, meeting optical requirements for device visualization.
- How long does it take to develop a custom silicone mold and start production?
Mold development takes 4–6 weeks (Обработка с ЧПУ + тестирование). After mold approval, production can start within 1 неделя. Для срочных проектов (НАПРИМЕР., medical device emergencies), we offer expedited mold development (2–3 недели) with priority production.