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China Zinc CNC Machining Suppliers - Precision Factory Solutions for Zinc Alloy Components and Die-Cast Parts
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.
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Common Zinc Alloy Grades and Characteristics
1. Zamak 3 (Zinc Alloy No. 3)
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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.
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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. | ||
2. Zamak 5 (Zinc Alloy No. 5)
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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.
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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. | ||
3. ZA-8 (Zinc-Aluminum Alloy No. 8)
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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.
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Typical Applications: Bearings, bushings, sliders, wear-resistant components, and engineering structural parts that need to operate in moderately elevated temperature environments.
4. Kirksite (Mold Zinc Alloy)
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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.
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Typical Applications: Prototype injection molds, blow molds, sheet metal stamping/form dies, checking fixtures, and jigs.
Frequently Asked Questions
What is the difference between Zamak 3 and Zamak 5?
Zamak 3 is the most commonly used die-casting zinc alloy, known for its excellent fluidity, dimensional stability, and ductility. Zamak 5 contains approximately 1% more copper, which increases its tensile strength, hardness, and creep resistance, making it better suited for structural and functional parts that require higher mechanical performance. However, Zamak 5 has slightly lower ductility and impact toughness compared to Zamak 3.
Why is zinc alloy a popular choice for die casting?
Zinc alloys offer exceptional castability, allowing the production of complex, thin-walled parts with tight tolerances. They have a relatively low melting point, which reduces energy consumption and extends mold life. Combined with good mechanical properties, excellent surface finish capability, and cost-effectiveness, zinc alloys are widely preferred for high-volume die casting applications.
Can zinc alloy parts be used for EMI/RFI shielding?
Yes. Zinc alloys provide comprehensive electromagnetic shielding (EMI/RFI) capability due to their metallic conductivity. This makes them suitable for housings and enclosures in electronic and communication devices where shielding sensitive components from electromagnetic interference is required.
What is ZA-8 best suited for compared to Zamak alloys?
ZA-8 is particularly well-suited for applications involving elevated temperatures, bearings, and wear-intensive environments. While Zamak alloys excel in standard die-casting applications, ZA-8 offers superior bearing properties, wear resistance, and better dimensional stability at moderately high temperatures, making it ideal for bushings, sliders, and engineering structural components.
What is Kirksite used for in manufacturing?
Kirksite is a specialized mold zinc alloy used primarily for prototype tooling and low-volume production molds. Its low melting point and excellent machinability make it ideal for quickly and economically producing injection molds, blow molds, stamping dies, checking fixtures, and jigs — especially during product development and small-batch trial production phases.
How does zinc alloy compare to aluminum alloy in terms of density and applications?
Zinc alloys have a significantly higher density (approximately 6.6–6.7 g/cm³) compared to aluminum alloys (approximately 2.6–2.8 g/cm³). While aluminum is preferred in weight-sensitive applications, zinc alloys offer superior castability for complex shapes, better surface finish, and higher dimensional accuracy in thin-walled parts, making them more suitable for intricate consumer products, hardware, and precision components.
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.
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Passivation or Chromate Conversion Coating:
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Powder Coating:
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Painting:
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Physical Vapor Deposition (PVD):
Design and Machining Considerations
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Process Selection:
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Design Considerations:
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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.
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