There are several different types of Die Casting, each with their own advantages suited to particular applications and production volumes. The main Die Cast process categories include:
(1)High Pressure
- Injection pressures from 15,000 to over 30,000 psi
- Forces metal into die at high speeds up to 100 mph
- Excellent dimensional accuracy and fine details
- Thin walls down to 0.015 inches possible
- Used for aluminum, magnesium, zinc alloys
- Highest tooling costs but low cost per part at volume
- Typical annual production quantities over 250,000 pieces
(2)Low Pressure Casting
- Lower injection pressures under 3000 psi
- Slower fill rates help avoid casting defects
- Mainly used for zinc and aluminum alloys
- Largest Castings over 50 lbs feasible
- More porosity than high pressure method
- Lower machine and tooling costs
- Production quantities from 1,000 to 1,000,000 pieces/year
(3)Squeeze Die Cast
- Pressurizes the metal once inside the die cavity
- No gate vestige since no runner system
- Excellent for casting aluminum
- Complex internally cored geometries
- Slow cycle time of 30-90 seconds
- Lower tooling costs than high pressure
(4)Semi-Solid Die Cast
- Thixotropic metal fed into die at lower pressures
- Minimal porosity defects in castings
- Heat treated properties comparable to wrought alloys
- More flexibility in alloy composition
- Suitable for magnesium and aluminum
At China Welong, we leverage experience across all Die Casting methods to select the optimal process for each customer's production application based on geometry, alloy, tolerances, and production volume.
What is the Difference Between Die Casting and Investment Casting?
They are two common production methods for metal components that share some similarities but have distinct differences:
1. Mold material - Steel dies vs. ceramic investment shells
- Die Cast uses reusable steel molds capable of thousands of cycles
- Investment casting uses disposable ceramic molds that must be broken after each casting
2. Production volume - High vs. low
- Die Cast is highly efficient for thousands to millions of castings per year
- Investment casting typically makes 50-5000 pieces per year
3. Cost basis - High setup costs vs. lower piece cost
- Die Cast has very high initial tooling costs but lower per part cost at volume
- Investment casting has lower mold costs but higher per piece cost
4. Metal force - High injection pressure vs. gravity fill
- Die Cast injects metal at high pressures up to 30,000 psi
- Investment casting relies on gravity to fill the ceramic molds
5. Geometries - Thin walls vs. unlimited contours
- Die Cast can make very thin castings down to 0.004 inches
- Investment can handle highly complex, interior geometries without design limits
6. Tolerances - Excellent vs. moderate
- Die Cast holds +/- 0.002 inch dimensional tolerances
- Investment casting typically holds +/- 0.02 inch tolerances
7. Finishes - Excellent vs. moderate
- Die Cast produces fine surface finishes around 64 Ra microinches
- Investment casting offers coarser ~250 Ra microinch finishes
Understanding these key differences allows selecting the best process for an application based on technical requirements and production needs.
What is Zinc Die Casting?
Zinc Die Casting refers to the production of zinc alloy castings using reusable steel molds, i.e. dies. Compared to other common alloys like aluminum or magnesium, zinc offers some unique benefits:
- Exceptional fluidity when molten, fills thin cross-sections with ease
- Low melting point of 780°F enables faster cycle times
- High dimensional accuracy and stability in service
- Cost-effective material compared to aluminum or magnesium
- Minimal post-casting machining required
- Readily platability for corrosion resistance and aesthetics
However, zinc also has some limitations versus other alloys:
- Lower strength than aluminum or magnesium alloys
- Limited temperature resistance, can creep under load at 120°C
- More reactive and can solder to die steel over time
Common zinc Casting alloys include:
- Zamak 3 alloy (Zn-4Al): most widely used, excellent strength and ductility
- Zinc 2 alloy (Zn-2Cu): highest zinc alloy strength, used for high wear applications
- Zinc 5 alloy (Zn-5Al): superior machinability, can be chrome plated
At China Welong, we have extensive experience Die Casting a wide range of alloys to achieve excellent dimensional accuracy, smooth surface finish, high productivity, and low cost per part. Please contact us at info@welongpost.com to discuss your specific needs!
References:
Mitterer, C., Modler, N., Körner, C., & Singer, R. F. (2011). High pressure Die Casting of aluminium alloys and metal matrix composites. Materials Science and Engineering: A, 528(10-11), 3689-3697.
Hu, B., Bao, R., Karnati, S., & Liou, F. (2021). Intelligence and automation in metal casting industry: A review. Journal of Manufacturing Systems, 60, 443-458.
Gourlay, C. M., Laukli, H. I., Dargusch, M. S., & Schumacher, P. (2022). Modeling and simulation approaches for quality improvement in aluminum Die Casting: A review. Metals, 12(4), 634.
Ghodke, N., Jadhav, N., Karnati, S., Anand, A., & Liou, F. (2022). Physics-informed machine learning model for real-time quality evaluation in aluminum high pressure Die Casting. Journal of Manufacturing Processes, 84, 24-35.
Wang, Q. G., Jiang, J. C., Wang, G. D., Zhang, M., Duan, S. Y., & Zhang, Z. D. (2021). Effects of trace Sm addition on microstructure evolution and mechanical properties of AZ91 alloy during sub-rapid solidification in high pressure Die Casting process. Journal of Alloys and Compounds, 855, 157659.
Çakır, U., Mekhrabov, A. O., Akça, E., & Beridze, G. (2019). Investigation of mechanical properties of aluminum alloys in high pressure Die Casting and low pressure casting methods. Metals, 9(3), 307.
