What is zinc die casting?
Zinc alloy is the easiest metal to cast, it offers superior ductility, high impact strength, and good machining ability that allows diverse kinds of secondary machining process like CNC machining, stamping, drilling, etc. Zinc die casting parts give excellent surface smoothness.
However zinc die casting parts is susceptible to corrosion and often requires additional surface treatment like coating or plating.
Zinc is economical for small die casting parts, as it has a low melting point and promotes long mold tool life.
Zinc alloy generally has good dimension stability that allows tighter dimensional tolerances. Meanwhile it is also optimal for complex shaped parts with thin walls while offering excellent electrical performance and other physical properties. it leaves us alternative for various parts surface treatment . Like powder coating, electroplating, and painting . This is why zinc casting becomes more and more popular.
For process, it normally requires to use a hot chamber die casting machines(it’s also called gooseneck machines) to force molten material into a die casting mold tool where it cools and solidifies to form a certain kind of shape or parts.
When to use zinc die casting?
Compared to aluminum and magnesium alloy die casing, zinc die casting parts have more accurate in dimension, complicated in part structure , thinner wall section, and durable in application. And the cost of zinc die casting is cheaper than aluminum die casting. This is the main reason why people choose it. On the other hand, it is quite easy to perform secondary machining and surface treatment. Like CNC machining, drilling, sand blasting, electroplating, etc.
Advantages of Zinc Die Casting Parts:
- Precision tolerances of die casting parts
- Extremely durable ,high impact strength and hardness
- Produces multi-cavity, complex shapes within closer tolerances than many other manufacturing processes.
- Excellent electrical conductivity
- High thermal conductivity
- Low cost for raw material, economical for small parts.
- High dimensional accuracy and stability
- Excellent thin wall capability
- Ability to cold form, which eases joining
- High quality finishing characteristics
- Outstanding corrosion resistance
- Full recyclability
- Easily plated or finished with minimal surface preparation.
- Easy finishing, smooth casting surfaces
- Rapid production rate
Zinc Material Profile:
- Atomic Mass: 65.39 amu
- Melting Point: 419.58 °C – 692.73 °K
- Boiling Point: 907.0 °C – 1180.15 °K
- Number of Protons/Electrons: 30
- Density @ 293 K: 7.133 g/cm3
- Natural Color: Bluish or white
Zinc Die Casting Application:
- Power Tools
- Consumer Electronics
Zinc alloy we use:
Zamak 2, Zamak 3,Zamak 5, Zamak8, Zamak12, Zamak27, Zamak35
The Zinc Die Casting Process
Zinc die casting requires to use a hot chamber die casting machines(it’s also called gooseneck machines) , die casting mold tool, and raw material.
During the process, the molten material inside of gooseneck machine is forced into a die casting mold tool where it cools and solidifies to form a certain kind of shape or products.
Here below are the six typical processes of zinc die casting:
1. Mold Tool Clamping and Lubrication
Prior to die casting process, a die casting mold tool should be mounted onto die casting machine firmly. The two half of mold tool should be opened up for lubrication, which makes die casting piece removal from mold tool easier.
2. Material Injection
After mold tool is closed, the molten material is forced into the mold tool under high pressure, where the injected product cools and solidifies latterly.
3. Cooling and Solidifying
The injected material inside die casting mold will cools and solidifies almost as soon as it enters the mold cavity. Normally it takes about few seconds to 50 seconds.
4. Product Ejection
Once the product has solidified, it will be ejected out by a mechanical device inside mold tool. The raw casting products will be either took out by manual or automation device.
When we get the raw casting piece, it’s time to remove additional material from casting products like runners, overflows, flash, sprue, etc.
6. Secondary Process and Surface Treatment
For some complex die casting part, we can’t obtain it directly from a die casting process. But we can achieve it by secondary process, like CNC machining, drilling, boring, milling, etc.
Once everything is finished, we will get it done for surface treatment as needed. Normally we do anodizing, powder spraying, electro-plating, etc.