The V-process casting technique, characterized by vacuum-sealed molding with dry sand and plastic films, has demonstrated significant advantages in producing high-quality aluminum alloy sand casting parts. This article explores its applications in refrigerator inner mold production, artistic relief design, and novel mold material development through systematic experiments and industrial case studies.
1. V-Process Implementation for Refrigerator Inner Molds
For complex sand casting parts like refrigerator inner cavity molds, we developed specialized production lines with modular tooling systems. Key innovations include:
| Technical Challenge | Solution | Implementation Effect |
|---|---|---|
| Frequent mold changes | Quick-change positioning system | Reduced setup time by 40% |
| Deep cavity molding | Secondary molding technique | Improved dimensional accuracy to ±2mm/1000mm |
| Cooling pipe embedding | U-shaped wire fixation | Positional accuracy <1.5mm |
The vacuum maintenance equation during molding can be expressed as:
$$
P_{\text{vac}} = P_{\text{atm}} – \frac{\mu Q}{A} \cdot \ln\left(\frac{V_0}{V}\right)
$$
Where \( P_{\text{vac}} \) is vacuum pressure, \( \mu \) represents sand permeability, and \( Q \) denotes vacuum flow rate.
2. Quality Comparison of Sand Casting Parts
Comparative studies of V-process, clay sand, and resin sand casting techniques revealed:
| Parameter | V-Process | Clay Sand | Resin Sand |
|---|---|---|---|
| Surface Roughness (Ra/μm) | 5.72 | 26.35 | 12.19 |
| Hardness (HV) | 55.7 | 63.6 | 65.6 |
| Tensile Strength (MPa) | 130.46 | 155.23 | 155.57 |
| Cooling Rate (°C/s) | 0.8-1.2 | 2.5-3.5 | 2.0-3.0 |
The microstructure evolution follows the relationship:
$$
\lambda_2 = k T^{-n}
$$
Where \( \lambda_2 \) represents secondary dendrite arm spacing, \( T \) is solidification time, and \( k,n \) are material constants.
3. Artistic Relief Applications
V-process casting enables precise replication of intricate details for artistic sand casting parts. For the 12 Chinese zodiac relief series:
| Design Parameter | Specification |
|---|---|
| Minimum Relief Depth | 0.8mm |
| Surface Resolution | 300dpi equivalent |
| Dimensional Tolerance | ±0.5mm/100mm |
| Production Cycle | 48 hours/relief |
4. Mold Material Innovations
Novel mold materials were developed for specialized sand casting parts production:
| Material | Cost (USD/m³) | Lifespan (cycles) | Surface Finish |
|---|---|---|---|
| Resin-coated EPS | 600 | 15-20 | Ra 3.2μm |
| Polyurethane Foam | 2000 | 25-30 | Ra 6.3μm |
| Acrylic Sheet | 120/m² | 50+ | Ra 1.6μm |
The film stretching ratio during thermoforming follows:
$$
\epsilon_{\text{max}} = \frac{\Delta L}{L_0} \times 100\% \leq 150\%
$$
Where \( \epsilon_{\text{max}} \) represents maximum allowable elongation for 0.12mm EVA film.
5. Conclusion and Perspectives
V-process casting demonstrates superior performance in manufacturing precision aluminum sand casting parts, particularly for applications requiring complex geometries and fine surface details. Future developments should focus on:
- Automated mold changing systems for small-batch production
- Hybrid molding techniques combining 3D printed cores
- Advanced vacuum control algorithms for large-scale sand casting parts
The continued innovation in V-process technology positions it as a sustainable solution for high-quality aluminum sand casting parts manufacturing across multiple industries.