+86-13928348837
China Zinc Alloy CNC Machining Services - Precision Parts from Reliable Suppliers and Factory
Zinc alloys typically refer to alloys with zinc as the base, primarily alloyed with elements such as aluminum, copper, and magnesium. Their most prominent feature is excellent castability, making them suitable for manufacturing parts with complex shapes.
Simultaneously, their superior machinability allows subsequent CNC precision machining to easily achieve high dimensional accuracy and excellent surface finish.
Furthermore, zinc alloys offer good wear resistance, damping capacity, and comprehensive electromagnetic shielding (EMI/RFI) capability, making them an engineering material that combines functionality with economy.
⚙
Common Zinc Alloy Grades and Characteristics
01
Zamak 3 (Zinc Alloy No. 3)
🔬 Characteristics
The most versatile and commonly used die-casting zinc alloy. It possesses the best fluidity and dimensional stability, along with good mechanical properties and surface treatment performance. Its low copper content means its creep resistance and strength are slightly lower than Zamak 5, but it offers better ductility.
🏭 Typical Applications
Complex thin-walled parts without extremely high strength requirements, such as toy models, zipper pulls, small gears, decorative items, and numerous consumer electronics housings.
Zamak 3 Typical Properties (As Die-Cast)
| Property | Value | Notes |
|---|---|---|
| Tensile Strength (MPa) | 280 – 320 | Good overall strength |
| Yield Strength (MPa) | — | |
| Elongation at Break (%) | 10 – 20 | Exhibits good ductility |
| Hardness (Brinell) | ~ 82 | |
| Density (g/cm³) | 6.6 | Significantly higher than aluminum and plastics |
| Note: Values are typical ranges, specific to casting process and condition. | ||
02
Zamak 5 (Zinc Alloy No. 5)
🔬 Characteristics
Based on Zamak 3 with the addition of about 1% copper, thereby increasing tensile strength, hardness, and creep resistance, but slightly reducing impact toughness and ductility. It is the most widely used high-strength die-casting zinc alloy.
🏭 Typical Applications
Functional and structural parts requiring higher strength and wear resistance, such as automotive door locks, fuel system components, tool housings, premium hardware, and business machine parts.
Zamak 5 Typical Properties (As Die-Cast)
| Property | Value | Notes |
|---|---|---|
| Tensile Strength (MPa) | 330 – 380 | Strength higher than Zamak 3 |
| Yield Strength (MPa) | — | |
| Elongation at Break (%) | 7 – 15 | |
| Hardness (Brinell) | ~ 91 | Higher hardness, more wear-resistant |
| Density (g/cm³) | 6.7 | Similar to Zamak 3 |
| Note: Values are typical ranges, specific to casting process and condition. | ||
03
ZA-8 (Zinc-Aluminum Alloy No. 8)
🔬 Characteristics
A zinc-aluminum alloy containing about 8.4% aluminum, typically produced by gravity casting. It has the best castability among all ZA series alloys and offers excellent bearing properties and wear resistance. Compared to the Zamak series, it retains better strength and dimensional stability at elevated temperatures.
🏭 Typical Applications
Bearings, bushings, sliders, wear-resistant components, and engineering structural parts that need to operate in moderately elevated temperature environments.
04
Kirksite (Mold Zinc Alloy)
🔬 Characteristics
A zinc-based alloy specifically designed for manufacturing prototype molds, low-melting-point injection molds, and fixtures. It has a low melting point, is easy to machine, and can quickly and cost-effectively replicate complex mold cavities for small-batch plastic part trial production or sheet metal forming.
🏭 Typical Applications
Prototype injection molds, blow molds, sheet metal stamping/form dies, checking fixtures, and jigs.
❓
Frequently Asked Questions (FAQ)
Q
What is the difference between Zamak 3 and Zamak 5 zinc alloys?
Zamak 3 offers superior ductility and the best fluidity for die casting, making it ideal for complex thin-walled parts. Zamak 5 contains approximately 1% more copper, which increases tensile strength, hardness, and creep resistance — making it the preferred choice for structural or functional parts that demand higher mechanical performance.
Q
Are zinc alloys suitable for CNC machining after die casting?
Yes. Zinc alloys exhibit excellent machinability, allowing CNC precision machining to achieve tight dimensional tolerances and high-quality surface finishes with ease. This makes them a popular choice for parts that require both complex casting geometry and precise machined features.
Q
What makes ZA-8 different from the Zamak series alloys?
ZA-8 contains approximately 8.4% aluminum, which gives it superior bearing properties, wear resistance, and better performance at elevated temperatures compared to the Zamak series. It is typically produced via gravity casting rather than pressure die casting, and is well suited for bearing and bushing applications.
Q
What is Kirksite used for, and why is it preferred for prototype molds?
Kirksite is a zinc-based alloy specifically designed for prototype tooling. Its low melting point makes it easy and inexpensive to cast into complex mold shapes. It is widely used for prototype injection molds, blow molds, and sheet metal forming dies, enabling rapid and cost-effective production of small batches before committing to hardened steel tooling.
Q
Do zinc alloys provide electromagnetic shielding (EMI/RFI) capabilities?
Yes. Zinc alloys offer comprehensive electromagnetic shielding (EMI/RFI) capability, which makes them particularly valuable for electronics housings and enclosures where interference shielding is required alongside structural integrity and cost efficiency.
Q
How do I choose the right zinc alloy grade for my application?
The selection depends on your specific requirements: choose Zamak 3 for maximum castability and ductility in decorative or consumer parts; choose Zamak 5 for higher strength and wear resistance in functional/structural components; choose ZA-8 for bearing or elevated-temperature applications; and choose Kirksite when you need fast, low-cost prototype tooling or fixture fabrication.
Finishes and Post-Processing Options
The zinc alloy substrate is highly suitable for various surface treatments to enhance decoration, protection, or functionality:
Electroplating: Such as chrome, nickel, gold, or silver plating, providing a highly decorative appearance, excellent wear and corrosion resistance. This is the most common choice.
-
Passivation or Chromate Conversion Coating:
-
Powder Coating:
-
Painting:
-
Physical Vapor Deposition (PVD):
Design and Machining Considerations
-
Process Selection:
-
Design Considerations:
-
Material Selection:
Zamak 3 and 5 are suitable for the vast majority of general-purpose parts requiring good appearance and strength; ZA-8 is better for wear and bearing applications; for making rapid tooling, choose specialized alloys like Kirksite.
Ready to Start Your CNC Project?
Send us your drawings to receive professional manufacturing solutions.