Cast aluminum prototypes are metal prototypes crafted from aluminum alloys via casting processes—such as die casting, coulée par gravité, ou coulée basse pression. Ils comblent le fossé entre la conception du produit et la production de masse en reproduisant la structure du produit final., propriétés des matériaux, et finition de surface, ce qui les rend idéaux pour valider la force, logique d'assemblage, et fonctionnalité en petits lots. This article breaks down their core traits, fabrication étape par étape, comparisons to other prototypes, and real-world applications to help teams make informed decisions.
1. What Defines Cast Aluminum Prototypes? Key Traits & Material Choices
To understand their value, start with their fundamental characteristics and the aluminum alloys that power them.
1.1 Core Traits
| Trait | Détails | Why It Matters |
| Compatibilité des matériaux | Uses the same aluminum alloys as mass-produced parts (par ex., ADC12, AlSi10Mg), ensuring test results reflect real-world performance. | Avoids “material mismatch” risks—e.g., a prototype’s strength test won’t be skewed by using a different alloy than the final product. |
| Capacité de forme complexe | Casts intricate structures: hollows, internal ribs, concave/convex surfaces, et des murs fins (down to 1mm thick). | Ideal for parts like automotive engine covers or electronic device housings that have complex geometries. |
| Cost-Effective for Small-Medium Batches | Low per-unit cost when producing 10–500 units (mold costs are amortized across batches). | Beats CNC machining (high per-unit cost) for small-batch testing and avoids the expense of mass-production steel molds. |
| Surface Treatment Versatility | Supports anodizing, spraying, galvanoplastie, and sandblasting—matching mass-production aesthetics. | Lets teams validate color (par ex., black anodization) ou texture (par ex., matte spraying) before scaling up. |
1.2 Aluminum Alloy Selection Guide
Choose alloys based on your prototype’s functional and structural needs:
| Alliage | Propriétés clés | Applications idéales |
| ADC12 | Excellente fluidité, easy to cast, faible coût. | Complex-shaped parts (par ex., laptop shells, lamp housings) where precision is moderate. |
| AlSi10Mg | Haute résistance (after T6 heat treatment), bonne résistance à la corrosion. | Pièces structurelles (par ex., supports automobiles, cadres de drones) requiring load-bearing capability. |
| ZL104 | Superior casting performance, suitable for thin-walled parts (≤2mm). | Electronic device middle frames, small mechanical components with tight space constraints. |
| 6061 | Bonne usinabilité (for post-casting tweaks), léger. | Parts needing additional CNC machining (par ex., trous filetés, precision slots) after casting. |
2. What Is the Step-by-Step Production Process?
The workflow follows a linear sequence, with each stage critical to avoiding defects like shrinkage or porosity.
2.1 Stage 1: Conception & Préparation du moule
- 3Modélisation D: Use CAD software (SolidWorks, AutoCAD) to create a model with:
- Draft angles: 1°–3° on vertical surfaces to ensure easy demolding (prevents parts from getting stuck in the mold).
- Riser/gate design: Risers (extra metal reservoirs) to fill shrinkage gaps; gates (entry points) placed to avoid air bubbles.
- Thickness uniformity: Avoid sudden thickness changes (par ex., from 5mm to 1mm) to prevent cracking during cooling.
- Fabrication de moules:
| Mold Type | Idéal pour | Fourchette de coût | Délai de mise en œuvre |
| Die Casting Mold (Acier: P20, H13) | Haute précision (±0,1mm), batches ≥50 units. | \(2,000–)8,000 | 7–14 jours |
| Gravity Casting Mold (Steel/Resin) | Faible coût, batches ≤10 units, formes simples. | \(500–)2,000 | 3–7 jours |
| Low-Pressure Casting Mold (Acier) | Medium precision (±0,2 mm), batches 10–50 units. | \(1,500–)5,000 | 5–10 jours |
2.2 Stage 2: Casting Execution
Select the casting method based on batch size and precision needs:
| Method | Aperçu du processus | Avantages | Disadvantages |
| Moulage sous pression | Aluminium fondu (650°C–700°C) is injected into the mold at high pressure (50–150 MPa) et la vitesse. | Haute précision (±0,1mm), surface lisse (Ra 1.6–3.2), production rapide. | High mold cost, risk of porosity (small air bubbles) in thick sections. |
| Gravity Casting | Molten aluminum fills the mold via gravity (no external pressure). | Low mold cost, simple setup, minimal porosity. | Lower precision (±0,5 mm), slower production (1–2 parts per hour). |
| Low-Pressure Casting | Molten aluminum is pushed into the mold at low pressure (0.1–0.5 MPa). | Balances precision and cost, reduces defects (porosité, inclusions). | Longer lead time than gravity casting, limited to medium batches. |
2.3 Stage 3: Post-traitement & Essai
- Garniture & Finition:
- Cut off gates/risers with a grinding wheel or CNC router.
- Polish burrs to achieve surface roughness (Ra 0.8–3.2) for anodizing/spraying.
- Traitement thermique (Facultatif):
- T6 aging treatment (solution heating + artificial aging) for AlSi10Mg or 6061 alloys—boosts strength by 30%–50%.
- Traitement de surface:
- Anodisation: Crée une couche d'oxyde protectrice (épaisseur: 5–20μm) in colors like silver, noir, ou de l'or.
- Pulvérisation: Applies powder coating (résistant aux rayures) or matte paint to match brand aesthetics.
- Sablage: Adds a textured finish (par ex., fine grit for a soft touch) to hide minor surface flaws.
- Assemblée & Tests fonctionnels:
- Assemble multiple cast parts (par ex., a housing + bracket) with screws or snaps.
- Test performance:
- Structural strength: Apply load (par ex., 10kg for an automotive bracket) and check for deformation (≤0.2mm).
- Résistance à la corrosion: Salt spray test (24 heures, 5% NaCl solution) pour les parties extérieures.
- Assembly fit: Ensure compatibility with non-cast components (par ex., a cast aluminum shell fitting a plastic circuit board).
3. How Do Cast Aluminum Prototypes Compare to Other Prototypes?
Use this comparison to choose the right prototype type for your needs:
| Comparison Factor | Cast Aluminum Prototype | Plastic Prototype (3D Printing/CNC) | Metal Prototype (Usinage CNC) |
| Matériel | Alliages d'aluminium (ADC12, AlSi10Mg) | PLA, ABS, résine | Aluminium, acier inoxydable, cuivre |
| Précision | Moyen (±0.1mm–±0.5mm) | Low–Medium (3Impression D: ±0,5 mm) | Haut (±0.05mm–±0.1mm) |
| Coût | Moyen (High mold fee, low per unit: \(10–)50/partie) | Faible (No mold fee: \(5–)30/partie) | Haut (No mold fee, high per unit: \(50–)200/partie) |
| Batch Suitability | 10–500 unités | 1–10 unités | 1–20 units |
| Strength/Heat Resistance | Haut (Withstands 150°C–250°C) | Faible (ABS melts at ~100°C) | Haut (Depends on metal) |
| Finition de surface | Lisse (Needs minimal post-processing) | En couches (Requires sanding/painting) | Lisse (Requires manual polishing) |
| Ideal Use Case | Validating structural parts (automobile, électronique) | Appearance prototypes (jouets, biens de consommation) | Pièces de précision (dispositifs médicaux, aérospatial) |
4. What Are the Key Application Scenarios?
Cast aluminum prototypes solve critical problems across industries where strength and scalability matter.
4.1 Industrie automobile
- Parties: Capots moteur, moyeux de roue, poignées de porte, dashboard frames.
- But: Test assembly logic (par ex., a hub fitting a tire), capacité portante (par ex., a bracket supporting engine weight), and heat dissipation (par ex., an engine cover withstanding high temperatures).
4.2 Industrie électronique
- Parties: Laptop shells, mobile phone middle frames, dissipateurs de chaleur.
- But: Validate structural strength (par ex., a laptop shell resisting drops) and electromagnetic shielding (par ex., a middle frame blocking interference).
4.3 Équipement industriel
- Parties: Mechanical supports, boîtes de vitesses, motor housings.
- But: Check temperature resistance (par ex., a motor housing in 120°C environments) et résistance à la corrosion (par ex., a support in wet factories).
4.4 Biens de consommation
- Parties: High-end lamp housings, furniture accessories, équipement sportif (par ex., cadres de vélo).
- But: Simulate mass-production aesthetics (par ex., anodized lamp finishes) and test durability (par ex., a bicycle frame withstanding impacts).
5. What Precautions Avoid Common Failures?
5.1 Optimisation de la conception
- Avoid uncastable features: Deep holes (>10mm depth) or sharp corners (≤0.5mm radius) cause mold sticking or cracking. Replace with rounded corners (≥1mm radius) or split holes into two sections.
- Ensure uniform cooling: Add cooling channels to thick sections (par ex., 10murs mm) to prevent shrinkage defects.
5.2 Cost Control
- Choose the right mold: Use gravity casting molds for batches ≤10 units (enregistre 50% contre. moules de moulage sous pression). For batches ≥50 units, die casting becomes more cost-effective (le coût unitaire diminue 30%).
- Combine with CNC machining: Cast most of the part, then use CNC to add precision features (par ex., trous filetés) instead of casting complex details—reduces mold cost by 20%.
5.3 Assurance qualité
- Pre-treatment for surface finishing: Sand the prototype to Ra 3.2 before anodizing—any scratches will show through the coating. Clean oil with isopropyl alcohol before spraying to avoid poor adhesion.
- Test for defects: Use X-ray inspection for critical parts (par ex., supports automobiles) pour détecter la porosité interne, which weakens structural strength.
Yigu Technology’s Perspective
Chez Yigu Technologie, we see cast aluminum prototypes as a “cost-saving bridge” between design and mass production. Too many clients rush to open steel molds for mass production without validating via cast prototypes—only to discover shrinkage cracks or poor assembly fit, costing \(10k–\)50k in reworks. Our approach: We help clients select the right alloy (par ex., AlSi10Mg for strength, ADC12 for complexity) and casting method (gravity for small batches, die casting for larger runs) to cut iteration time by 40%. Par exemple, we helped an automotive client fix a bracket’s load-bearing issue by adjusting the mold’s riser design—avoiding a $20k mold rework. For small-medium batches, cast aluminum prototypes aren’t just an option—they’re the most efficient way to de-risk production.
FAQ
- Can cast aluminum prototypes be used for high-temperature applications (par ex., pièces de moteur)?
Yes—choose heat-resistant alloys like AlSi10Mg (withstands up to 250°C after T6 treatment) or ZL109 (jusqu'à 300°C). Add heat treatment to enhance thermal stability, and test via thermal cycling (-40°C à 150°C) to ensure durability.
- What’s the minimum batch size for cast aluminum prototypes to be cost-effective?
For gravity casting: 10 unités (mold cost ~\(1,000 amortized to \)100/partie). For die casting: 50 unités (mold cost ~\(5,000 amortized to \)100/partie)—below these numbers, 3D printing or CNC machining may be cheaper.
- How long does it take to produce a cast aluminum prototype?
Total lead time: 7–21 jours. Mold making takes 3–14 days (gravity casting fastest, die casting slowest), casting takes 1–3 days, et post-traitement (finition, essai) takes 3–4 days. Add 2–3 days for design tweaks if needed.