What You Need to Know About Vacuum Die Casting Technology?

Vacuum die casting technology has become a game-changer in manufacturing, addressing critical flaws in traditional die casting to produce high-quality, high-density parts. This article dives into its core principles, процессы, преимущества, and practical applications—equipping you with actionable insights to leverage this technology effectively.

1. Основные понятия: How Does Vacuum Die Casting Work?

По своей сути, vacuum die casting is an upgraded version of traditional pressure casting, enhanced by a vacuum environment. The key is to eliminate gas-related defects by controlling the air pressure in the mold cavity.

Основной принцип

Traditional die casting often traps air and gas impurities in the molten metal, leading to porosity (крошечные отверстия) and looseness. Vacuum die casting solves this by extracting gas from the mold cavity synchronously during the casting process, creating a negative pressure environment. This inhibits the mixing of molten metal and gas, ultimately improving the casting’s density and mechanical properties.

Key Difference from Traditional Die Casting

To highlight its uniqueness, here’s a direct comparison:

2. Core Process Steps: A Linear Workflow

Vacuum die casting follows a structured, step-by-step process to ensure consistency and quality. Each stage is critical to achieving the desired results:

1. Подготовка плесени

• Preheat the mold to the optimal temperature (варьируется в зависимости от материала, НАПРИМЕР., 150–250°C for aluminum alloys).
• Spray a high-quality release agent to prevent the molten metal from sticking to the mold.
• Ensure mold tightness—pay special attention to parting surfaces, ползунки, and other key areas to avoid air leakage.

2. Vacuum Stage

There are two common methods, each suited for different part designs:

• Pre-vacuum: After closing the mold, extract gas until the cavity reaches the set vacuum level (обычно <50 mbar) before injecting molten metal. Ideal for simple-structured parts.
• Dynamic Evacuation: Continuously extract gas пока the molten metal fills the cavity. Perfect for complex-structured castings (НАПРИМЕР., Автомобильные блоки двигателя) where gas can get trapped in narrow channels.

3. Liquid Metal Filling & Pressurization

• Inject molten metal into the vacuum-sealed cavity at a controlled speed.
• Once filled, the injection punch applies high pressure (typically 50–150 MPa) to compact the metal, reducing shrinkage and enhancing density.

4. Охлаждение & Демольд

• Cool the casting until it reaches the safe demolding temperature (варьируется в зависимости от материала).
• Remove the casting and perform optional post-processing: термическая обработка (НАПРИМЕР., T6 for aluminum) or machining to meet precise dimensions.

3. Ключевые преимущества: Why Choose Vacuum Die Casting?

The technology’s popularity stems from its ability to solve long-standing manufacturing pain points. Ниже приведены его наиболее важные преимущества., supported by specific data and use cases:

• Superior Casting Quality
• Высокая плотность (>98% theoretical value) boosts mechanical properties (предел прочности, устойчивость к усталости) by 15–20% compared to traditional casting.
• Превосходное качество поверхности: No need for porosity removal processes—parts can be directly electroplated, окрашен, or assembled.
• Strong Process Adaptability
• Идеально подходит для тонкостенные детали (wall thickness ≤1 mm), such as lightweight automotive components.
• Handles complex structures: Produces parts like automobile transmission housings or aerospace brackets with intricate internal channels.
• Heat Treatment Friendly

Traditional castings often blister during heat treatment (due to trapped gas expanding). Vacuum die casting reduces this risk significantly, allowing castings to undergo processes like T6 heat treatment for enhanced hardness.

• Cost-Efficiency in the Long Run

While initial equipment costs are higher than traditional die casting, the lower scrap rate (reduced by 30–40%) and minimized post-processing costs create a clear comprehensive cost advantage—especially for high-volume production.

4. Critical Technical Points: Избегайте общих ловушек

To maximize the benefits of vacuum die casting, focus on these four technical priorities:

1. Exhaust Duct Design

The exhaust duct has a “critical area”—a threshold for effective gas extraction. If the duct area is larger than the critical area, the vacuum effect is significant; if smaller, the effect is negligible. Например, for aluminum castings, the critical area is typically 0.5–1.0 mm² per kg of molten metal.

2. Vacuum System Selection

The system must maintain the cavity’s vacuum level until filling is complete before closing the vacuum pump. Early valve closure leaves residual gas; delayed closure risks molten metal entering and blocking the valve.

3. Vacuum Valve Control

Клапаны (mechanical or hydraulic solenoid) must match the process:

• Mechanical valves: Suitable for simple, low-speed processes (НАПРИМЕР., pre-vacuum for small parts).
• Hydraulic solenoid valves: Better for high-speed, dynamic evacuation (НАПРИМЕР., complex automotive parts), offering faster response times.

4. Mold Tightness

Even minor air leakage can ruin the vacuum effect. Regularly inspect and maintain:

• Parting surfaces (clean and align to prevent gaps).
• Slider seals (replace worn seals to avoid air ingress).

5. Typical Application Scenarios

Vacuum die casting excels in industries where part quality, плотность, и надежность не подлежит обсуждению. Вот его наиболее распространенное использование:

Перспектива Yigu Technology

В Yigu Technology, we see vacuum die casting as more than a process—it’s a solution to meet the growing demand for high-performance parts. Our clients in automotive and aerospace often require parts with <0.1% porosity and T6 heat treatment compatibility. To deliver this, we integrate custom exhaust duct designs (tailored to part geometry) and real-time vacuum monitoring systems, ensuring consistent cavity pressure (<30 mbar) during filling. We’ve also optimized mold maintenance protocols, cutting air leakage issues by 60%. Для производителей, adopting vacuum die casting isn’t just an upgrade—it’s a way to stay competitive in markets where quality and efficiency define success.

Часто задаваемые вопросы

1. What is the maximum wall thickness for parts made with vacuum die casting?

While vacuum die casting excels at thin-walled parts (≤1 мм), it can also handle thicker parts (до 10 мм). Однако, thicker sections may require adjusted cooling times to avoid internal shrinkage.

2. Can vacuum die casting be used for all metals?

It works best with non-ferrous metals like aluminum, магний, and zinc alloys—these metals have lower melting points and flow easily in a vacuum. It is less common for ferrous metals (НАПРИМЕР., сталь) due to their high melting points, which can damage vacuum system components.

3. How much does vacuum die casting equipment cost compared to traditional die casting?

Vacuum die casting equipment costs 30–50% more upfront. But with lower scrap rates (reduced by 30–40%) and less post-processing, most manufacturers recoup the investment within 1–2 years of high-volume production.