Dans la fabrication moderne, des boîtiers de transmission automobile aux boîtiers d'électronique grand public, le processes of die casting determine part quality, efficacité de production, et rentable. These processes aren’t a one-size-fits-all solution; they range from basic high-pressure methods to advanced semi-solid technologies, each tailored to specific material needs (zinc, aluminium, magnésium) et exigences de demande (production de masse, haute précision). This article breaks down core process categories, technical principles, scénarios d'application, et stratégies de sélection, helping you match the right die casting process to your production goals.
1. What Are the Basic Processes of Die Casting?
Basic die casting processes form the foundation of industrial production, focusing on high efficiency and cost-effectiveness. Casting à haute pression (HPDC) is the most widely used, with two sub-types based on metal melting points:
1.1 Casting à haute pression (HPDC): The Industry Mainstream
HPDC injects molten metal into closed steel molds at high pressure (30-120MPA) et la vitesse (0.5-120MS), enabling rapid solidification (0.05-0.5 secondes) pour pièces produites en série. It’s divided into two variants:
| Variante de processus | Principe de base | Paramètres clés | Suitable Metals | Avantages | Limites | Applications typiques |
| Moulage de la chambre froide | Molten metal is poured into an independent “cold chamber” (not in direct contact with the furnace) before injection; The chamber is cooled to prevent metal solidification during waiting | – Pression d'injection: 50-120MPA- Température de moisissure: 150-250° C- Temps de cycle: 30-120 secondes/partie | Métaux à point de fusion élevé: Aluminium (A380, A356), magnésium (AZ91D) | – Handles large/complex parts (up to 50kg)- Avoids mold overheating (prolonge la durée de vie du moule à 100,000+ cycles)- Suitable for high-strength parts | – Longer cycle time vs. hot chamber- Coût d'équipement plus élevé | Supports de batterie NEV, automotive engine housings, pièces structurelles aérospatiales |
| Casting de Die Chamber Hot | The injection system (plunger, ajutage) is fully immersed in a molten metal furnace; Metal is sucked into the chamber directly for fast injection | – Pression d'injection: 30-80MPA- Température de moisissure: 100-180° C- Temps de cycle: 10-30 secondes/partie | Métaux à bas point de fusion: Zinc (Zamak5, ZA27), plomb, étain | – Ultra-fast production (ideal for mass batches >100,000 parties)- Simple operation (low labor cost)- Faible consommation d'énergie (no need to reheat metal) | – Limited to small parts (<5kilos)- Mold prone to corrosion (shorter life: 50,000-80,000 cycles) | Zinc alloy toys, electronic sensor housings, garniture décorative (Par exemple, poignées de porte) |
2. What Are the Improved Die Casting Processes?
Improved processes address flaws in basic HPDC (Par exemple, porosité, faible précision) by optimizing mold design, gas control, or injection methods. They’re critical for high-quality parts like pressure-bearing components:
| Improved Process | Key Innovation | Détails techniques | Problème résolu | Applications idéales |
| Non-Porous Die Casting | Adds a vacuum system to remove air from the mold cavity before injection | – Vacuum degree: -0.095 à -0.098MPA- Gas removal rate: >95%- Works with cold/hot chamber systems | Reduces porosity by 80-90% (a major cause of leakage in basic HPDC); Élimine les vides internes | Zinc alloy hydraulic valve bodies, aluminum alloy fuel injector nozzles |
| Direct Injection Die Casting | Integrates the furnace with the injection chamber (no separate pouring step); Uses a plunger to push metal directly into the mold | – Metal utilization rate: >98% (contre. 85-90% for basic HPDC)- No sprue waste (cuts material cost by 10-15%) | Réduit les déchets de matériaux; Shortens cycle time by 15-20% | High-volume aluminum parts (Par exemple, consumer electronics midframes), zinc alloy hardware |
| Précision & Dense Die Casting | Invented by General Dynamics; Uses ultra-precise mold machining (cavity tolerance: ± 0,01 mm) + high-specific-pressure compensation (120-150MPA) | – Rugosité de surface: RA ≤0,8 μm (no post-polishing needed)- Précision dimensionnelle: IT7-IT8 (better than basic HPDC’s IT8-IT10)- Densité de pièce: ≥99.5% | Improves surface quality and precision; Enables parts to meet strict assembly requirements | Aerospace aluminum components (Par exemple, supports de cabine), Enveloppes de dispositifs médicaux (Par exemple, Poignées d'outils chirurgicaux) |
3. What Are the Special Die Casting Processes?
Special processes cater to niche needs: intégration multi-matériaux, ultra-fast production, or semi-solid forming. They expand die casting’s application scope beyond traditional metals and shapes:
3.1 Multi-Color/Multi-Material Die Casting
- Définition: Completes die casting of two or more colors/materials in one mold cycle (Par exemple, alliage de zinc + alliage en aluminium, or different colored zinc alloys).
- Comment ça marche:
- D'abord, inject the base material (Par exemple, silver zinc alloy) into the first cavity;
- Rotate the mold or move the core to align with the second cavity;
- Injectez le deuxième matériau (Par exemple, black zinc alloy) to bond with the base.
- Avantages: Élimine après l'assemblage (cuts labor cost by 30-40%); Ensures tight material bonding (pas de lacunes).
- Applications: Pièces intérieures automobiles (Par exemple, two-tone dashboard frames), électronique grand public (Par exemple, multi-color phone cases).
3.2 High-Speed Die Casting
- Définition: Uses a high-speed injection system (up to 200m/s) and advanced mold cooling (water channels every 5-10mm) to achieve ultra-fast filling and solidification.
- Paramètres clés:
- Temps de remplissage: <0.05 secondes (contre. 0.05-0.2 seconds for basic HPDC);
- Mold cooling rate: 50-100° C / S (accelerates solidification);
- Précision: Part tolerance ±0.02mm.
- Avantages: Produces complex thin-walled parts (épaisseur minimale de paroi: 0.3-0.5MM); Maintient la stabilité dimensionnelle (Pas de déformation).
- Applications: Thin aluminum alloy heat sinks (for 5G base stations), micro-zinc parts (Par exemple, Regarder des engrenages).
3.3 Moulage sous pression semi-solide
- Définition: Heats metal to a “solid-liquid coexistence” state (40-60% solid phase, 60-40% liquid phase) instead of fully molten; Uses laminar flow filling (0.1-0.5MS) pour éviter les turbulences.
- Technical Benefits:
- Microstructure: Grains sphériques fins (5-50µm) contre. coarse dendrites in basic HPDC;
- Propriétés mécaniques: Résistance à la traction +20-30%, élongation +50-80%;
- Durée de vie du moule: Extended by 30-50% (lower thermal shock from semi-solid metal).
- Applications: High-performance aluminum parts (Par exemple, NEV motor housings), magnesium alloy aerospace components (Par exemple, small landing gear brackets).
4. How to Choose the Right Die Casting Process?
Process selection depends on 5 core factors—ignoring any leads to poor quality or high costs. Below is a step-by-step decision guide:
Étape 1: Match Process to Material
- Aluminum/Magnesium (Point de fusion élevé): Cold chamber HPDC (basique), non-porous die casting (improved), semi-solid die casting (special).
- Zinc (Low Melting Point): Hot chamber HPDC (basique), non-porous die casting (improved), multi-color die casting (special).
Étape 2: Consider Part Size & Complexité
| Part Characteristic | Recommended Process | Raison |
| Petit (<5kilos) + Simple Shape | Hot chamber HPDC | Temps de cycle rapide; Faible coût |
| Grand (>10kilos) + Complex Structure | Cold chamber HPDC + precision mold | Handles size/complexity; Ensures accuracy |
| Thin-Walled (<1MM) + Haute précision | High-speed die casting | Ultra-fast filling avoids incomplete forming |
Étape 3: Align with Production Volume
- Low Volume (<10,000 parties): Basic HPDC (low mold cost; no need for advanced equipment).
- Medium Volume (10,000-100,000 parties): Improved processes (Par exemple, non-porous die casting) to balance quality and cost.
- Volume élevé (>100,000 parts): Hot chamber HPDC (zinc) or direct injection die casting (aluminium) for maximum efficiency.
Étape 4: Prioritize Quality Requirements
- Pièces sous pression (No Leakage): Non-porous die casting (faible porosité).
- High-Precision Assembly (Tolerance ±0.02mm): Précision & dense die casting.
- Forte résistance (Tensile Strength >300MPa): Moulage sous pression semi-solide.
5. Yigu Technology’s Perspective on Processes of Die Casting
À la technologie Yigu, Nous voyons le processes of die casting as a “production strategy toolbox”—the right choice depends on balancing quality, coût, et volume. Nos données montrent 70% of die casting failures come from process-material mismatches (Par exemple, using hot chamber HPDC for aluminum parts).
Nous recommandons une approche « axée sur la demande »: For NEV battery brackets (grand, high-strength aluminum parts), we use cold chamber HPDC + non-porous technology (assure l'étanchéité à l'air); For zinc alloy sensor housings (petit, volume élevé), we opt for hot chamber HPDC (cuts cycle time to 15 secondes/partie). We also integrate AI to monitor process parameters (Par exemple, pression d'injection, température du moule) en temps réel, réduire les taux de défauts à <1%. Regarder vers l'avenir, semi-solid and multi-material processes will be key to meeting lightweight and integration needs in automotive and electronics.
6. FAQ: Common Questions About Processes of Die Casting
T1: Can I use non-porous die casting for both aluminum and zinc alloys?
Oui. Non-porous die casting works with both cold (aluminium) and hot (zinc) chamber systems. Pour l'aluminium, it reduces porosity to <0.5% (critical for pressure-bearing parts like hydraulic valves); For zinc, it eliminates internal voids (improving corrosion resistance for outdoor hardware). The only adjustment needed is mold temperature (150-250°C pour l'aluminium, 100-180°C pour le zinc).
T2: What’s the difference between precision & dense die casting and basic HPDC in terms of cost?
Précision & dense die casting has higher upfront costs (Coût de la moisissure: 2-3x basic HPDC, due to ultra-precise machining) but lower long-term costs. Par exemple, a zinc alloy medical device casing: Basic HPDC requires \(5,000 moule + \)0.5/part post-polishing; Précision & dense die casting uses \(12,000 mold but no post-processing. Pour les lots >100,000 parties, precision die casting is cheaper (total cost: \)62,000 contre. $55,000 for basic HPDC).
T3: Is high-speed die casting suitable for thick-walled parts (>5MM)?
Non. High-speed die casting is designed for thin-walled parts: Its fast cooling rate (50-100° C / S) causes thick-walled areas to solidify unevenly, leading to shrinkage cavities. Pour pièces à parois épaisses (Par exemple, blocs de moteur automobile), use cold chamber HPDC with a high-specific-pressure compensation system (120-150MPA) pour assurer une solidification uniforme et éviter les défauts.