Semi-solid die casting and ordinary die casting are two core technologies in metal forming, each optimized for different production needs. While both inject metal into molds to create parts, their fundamental differences in metal state, process control, and performance make them suited for distinct applications—from high-strength automotive components to low-cost consumer goods. But what exactly sets them apart? How do these differences impact cost, efficienza, e qualità in parte? And how do you choose the right technology for your project? This article answers these questions with detailed comparisons and actionable insights.
1. Definizioni fondamentali & Principles: The Fundamental Gap
The biggest difference between the two technologies lies in the state of the metal durante l'elaborazione, which shapes their entire working mechanisms.
UN. Ordinary Die Casting
- Metal State: Usi fully molten liquid metal (PER ESEMPIO., aluminum alloy heated to ≥650°C). The metal flows like water, with low viscosity and Newtonian fluid characteristics.
- Core Mechanism: Fa affidamento su high speed and high pressure (typical pressure: 100–150MPa) to force liquid metal to fill complex mold cavities quickly (often in <0.1 Secondi). Rapid cooling in the mold then solidifies the metal into the desired shape.
- Microstructure Result: Due to fast cooling, the final part has fine but unevenly distributed grains, plus a large number of eutectic structures. This often leads to defects like shrinkage holes E stomata (porosità), especially in thick-walled areas.
B. Pressofusione semisolida
- Metal State: Usi semi-solid slurry or billets—a solid-liquid coexistence state (solid fraction: 50–90%). The metal behaves like “toothpaste”: spesso, viscous, and non-Newtonian (its flowability improves with shear force).
- Core Mechanism: Leverages the high viscosity and non-dendritic microstructure of semi-solid metal. It fills the mold at a slower, more controlled speed (no turbulent splashing), reducing gas entrainment and defect risks.
- Microstructure Result: Spherical primary solid phase particles are evenly distributed in the liquid phase. After solidification, the part has fine spherical grains and a fibrous matrix, leading to better mechanical property uniformity (isotropia) and fewer defects.
2. Side-by-Side Process Comparison: Key Operational Differences
To understand how these technologies perform in practice, let’s compare their process steps, parametri, and constraints in a clear table:
| Process Aspect | Ordinary Die Casting | Pressofusione semisolida |
| Metal Pretreatment | Semplice: Melt metal directly to a liquid state; no special preparation. | Complesso: Requires semi-solid slurry/billet production (via mechanical mixing, electromagnetic stirring, or low-temperature deposition). |
| Filling Characteristics | High-speed jetting (Spesso >5SM); prone to eddy currents and metal splashing. | Lento, smooth filling (in genere <2SM); high viscosity prevents turbulence. |
| Typical Operating Pressure | 100–150MPa (needs high pressure to overcome liquid metal inertia). | 60–100MPa (lower pressure due to reduced flow resistance of semi-solid metal). |
| Mold Heat Load | Extremely high (liquid metal releases large latent heat); requires a powerful cooling system (PER ESEMPIO., water channels every 20mm). | Basso (semi-solid metal has less latent heat to release); cooling system can be simpler. |
| Solidification Shrinkage | Grande (liquid metal contracts significantly during cooling); easy to form shrinkage defects. | Più piccolo (solid phase already dominates the metal, reducing total contraction). |
| Spessore murale minimo | Capable of ultra-thin walls (fino a 0,5 mm); ideal for lightweight parts. | Limitato (typical minimum: ≥1mm); semi-solid metal’s viscosity struggles to fill tiny gaps. |
| Tempo del ciclo | Extremely fast (<30 secondi per parte); no extra steps for slurry preparation. | Più lungo (45–90 secondi per parte); includes time for slurry production or billet reheating. |
3. Prestazione & Applicazione: Which Shines Where?
The process differences directly translate to distinct performance advantages—making each technology better suited for specific part types.
UN. Performance Comparison
| Metrica delle prestazioni | Ordinary Die Casting | Pressofusione semisolida |
| Resistenza alla trazione | Inferiore (PER ESEMPIO., 200–250MPa for aluminum alloys). | Più alto (15–30% increase; PER ESEMPIO., 230–325MPa for aluminum alloys). |
| Allungamento | Basso (typically 2–5% for aluminum parts). | Doubled (4–10% for aluminum parts); spherical grains hinder crack propagation. |
| Tasso di difetto | Alto (porosity and shrinkage are common; Tasso di rottami: 5–12%). | Basso (greatly reduces stomata and shrinkage; Tasso di rottami: 1–3%). |
| Heat Treatment Stability | Povero (heat treatment often expands existing pores, causing deformation). | Eccellente (uniform microstructure resists deformation; suitable for T6 heat treatment). |
| Costo per parte | Basso (\(0.3- )1 per kg for aluminum parts); mature equipment and simple process. | Alto (\(0.8- )2 per kg for aluminum parts); needs special slurry equipment. |
B. Scenari di applicazione: Choosing the Right Fit
The table below maps each technology to its ideal use cases, based on performance and cost needs:
| Part Requirement | Prefer Semi-Solid Die Casting | Prefer Ordinary Die Casting |
| Safety-Critical Parts | Automotive steering knuckles, pinze a freni (need high strength and low defects). | None—safety parts require reliability beyond ordinary die casting’s capabilities. |
| Pressure-Resistant Components | Hydraulic valve bodies, air compressor cylinders (no pores to leak under pressure). | Piccoli recinti elettrici (no pressure load; cost is key). |
| High-Toughness Needs | Motorcycle hubs, golf heads (must withstand impact without cracking). | Toy models, Staffe semplici (low impact risk). |
| High-Temperature Service | Engine head brackets (stable microstructure resists heat deformation). | Cookware handles (low heat exposure; cost matters more). |
| Ultra-Thin or High-Volume Parts | None—struggles with thin walls and slow cycle times. | Home appliance shells, lamp frames, Involucri di elettronica di consumo (Volume elevato, basso costo). |
4. Attrezzatura & Costo: The Investment Tradeoff
Choosing between the two technologies also means evaluating upfront and long-term costs, driven by equipment differences.
UN. Equipment Requirements
| Tipo di attrezzatura | Ordinary Die Casting | Pressofusione semisolida |
| Core Machine | Standard die casting machine (PER ESEMPIO., 200–300-ton models); widely available. | Specialized machine with slurry feeding systems; often custom-built. |
| Pretreatment Gear | Basic melting furnace (no extra tools needed). | Slurry preparation equipment (PER ESEMPIO., electromagnetic stirrers, low-temperature deposition units). |
| Design dello stampo | Simple molds (focus on fast cooling; no special flow controls). | Molds with optimized gating (to handle viscous semi-solid metal; may need larger runners). |
B. Composizione dei costi (Parti in lega di alluminio, 10,000-Part Batch)
| Categoria dei costi | Ordinary Die Casting | Pressofusione semisolida |
| Equipment Investment | \(50,000- )100,000 (standard machine + forno). | \(150,000- )300,000 (specialized machine + slurry gear). |
| Costo della muffa | \(5,000- )15,000 (Design semplice, no complex features). | \(10,000- )25,000 (optimized for semi-solid flow). |
| Per-Part Material Cost | \(0.3- )0.5 (higher waste rate: 10–15% due to defects). | \(0.4- )0.6 (lower waste rate: 3–5% fewer defects). |
| Total Batch Cost | ~ (8,000- )17,500 | ~ (25,000- )51,000 |
5. Technological Evolution: Tendenze future
Both technologies are evolving to address their limitations—with semi-solid casting leading in innovation for high-performance needs.
UN. Semi-Solid Die Casting Innovations
- Intelligent Slurry Control: Real-time electromagnetic stirring devices now monitor and adjust the solid fraction (to ±2%) during slurry production, ensuring consistent metal quality.
- Composite Molding: Combining semi-solid casting with squeeze casting further increases part density (reducing remaining porosity to <0.5%).
- New Material Adaptation: Expanding to magnesium alloys (più leggero dell'alluminio) and high-entropy alloys (superior heat resistance), opening doors for aerospace applications.
- Green Manufacturing: Uses ~20% less energy than ordinary die casting (no need to fully melt metal), Allineare con gli obiettivi di sostenibilità.
B. Ordinary Die Casting Improvements
- Defect Reduction: Adding vacuum systems to remove gas during filling reduces porosity by 30–40%.
- Automazione: Fully automated lines (with robotic part removal) cut labor costs by 50% and boost cycle time consistency.
6. Yigu Technology’s Perspective on the Two Technologies
Alla tecnologia Yigu, we see semi-solid and ordinary die casting as complementary tools—not competitors. For automotive clients needing safety parts (PER ESEMPIO., pinze a freni), our semi-solid die casting solutions (equipped with real-time slurry monitoring) deliver tensile strength gains of 25% and scrap rates below 2%, meeting IATF 16949 standard. For consumer electronics clients, our optimized ordinary die casting lines (con degassante sotto vuoto) reduce costs by 30% while keeping defects low enough for non-load parts.
We’re investing in “hybrid manufacturing” models: using semi-solid casting for high-strength main structures and ordinary casting for secondary features (PER ESEMPIO., integrated die-cast automotive bodies). This balances performance and cost, helping clients avoid overpaying for technology they don’t need. Our goal is to tailor each solution to the part’s actual requirements—no one-size-fits-all.
Domande frequenti
- Can semi-solid die casting be used for ultra-thin parts (PER ESEMPIO., 0.5mm muri)?
No—semi-solid metal’s high viscosity makes it hard to fill tiny gaps. Parti ultra-sottili (≤0.8mm) are better suited for ordinary die casting, which uses low-viscosity liquid metal to reach narrow cavities. For parts with mixed thicknesses (PER ESEMPIO., a 1mm main body + 0.6costole mm), consider hybrid designs: use semi-solid casting for the main body and post-machine the thin ribs.
- Is semi-solid die casting worth the higher cost for non-safety parts?
It depends on the part’s function. If the part needs to withstand impact, pressione, or heat (PER ESEMPIO., raccordi idraulici), yes—semi-solid casting’s durability reduces long-term maintenance costs. If it’s a non-load decorative part (PER ESEMPIO., paralumi), ordinary die casting is more cost-effective. We recommend calculating the “total cost of ownership” (not just per-part cost) to decide.
- Le normali parti pressofuse possono essere trattate termicamente per eguagliare le prestazioni di fusione semisolida?
Raramente, i normali componenti pressofusi presentano pori nascosti e microstrutture irregolari. Trattamento termico (PER ESEMPIO., T6) spesso espande questi pori, causando deformazioni o addirittura fessurazioni. Parti semisolide in fusione, con i loro grani sferici uniformi, può gestire il trattamento termico senza problemi, ma le parti ordinarie in genere non possono raggiungere gli stessi guadagni di resistenza. Per parti trattate termicamente, la fusione semisolida è la scelta più affidabile.