How Zinc Alloy Die Casting Works for Custom Medals

Custom medals symbolize achievement, pride, and identity at sports events, marathons, school competitions, and brand promotions. For durable, detailed, and stylish results, many organizations turn to zinc alloy die casting. This process delivers medals with exceptional definition, customizable relief, and finishes that stand out from the crowd. In this guide, you’ll learn how zinc alloy die casting creates custom medals, step by step, and when it’s the best choice for your project.

Understanding Zinc Alloy Die Casting

Zinc alloy die casting is a manufacturing process that forms metal parts by injecting molten zinc alloy under high pressure into custom molds. This method allows precise, repeatable shaping—even for complex 3D designs. The finished medals feature strong, crisp details that stamping or etching methods can’t replicate. Let’s walk through each step, from concept to completion.

Mould Making: Crafting the Foundation for Custom Medals

Every custom medal begins with a mould (also called a die)—the tool that gives each piece its unique shape and features. The mould creation process combines advanced computer-aided design (CAD) with hands-on craftsmanship:

1. Designers use CAD software to lay out the medal’s exact size, relief (depth), logo, and inscriptions.
2. Engineers review the drawings for structural integrity and smooth release from the die.
3. Precision machining—often with CNC milling or wire EDM—creates the steel die blocks. Each die is tailored to the medal’s design, including the front and back (if double-sided).
4. Final hand-polishing removes any micro-imperfections and ensures crisp detail in the finished product.

Gairun, for example, uses high-grade tool steel and controls tolerances within 0.02 mm for complex 3D relief to ensure medals match your vision exactly.

Melting and Alloy Preparation

Once the die is ready, it’s time to prepare the raw material. Zinc alloy (typically Zamak 3 or Zamak 5) offers the right balance of strength, ductility, and castability for medals:

• The foundry melts solid zinc ingots in a furnace at around 400°C (750°F), adding precise percentages of aluminum, magnesium, and copper to fine-tune properties like hardness and corrosion resistance.
• Strict quality checks, including spectrometer analysis, confirm the correct alloy composition before casting begins.

Proper alloy preparation ensures medals will last, maintain their finish, and pass RoHS and REACH compliance for global distribution.

Injection: Pouring Molten Metal into the Die

The heart of the die casting process is injection. Here’s how it works:

1. The die—or mould—is clamped shut in a die casting machine.
2. Molten zinc alloy is injected under high pressure (typically 10,000–30,000 psi) into the die cavity.
3. The force fills every detail and cavity, reproducing sharp text, logos, and surface effects—even for intricate or 3D medal shapes.

Automation controls speed, temperature, and pressure, minimizing porosity and ensuring consistent quality. This is especially important for high volumes, such as thousands of medals for a marathon or nationwide fundraiser.

Cooling and Solidification

As soon as molten metal enters the die, cooling begins. Efficient cooling is crucial for sharp details and dimensional stability:

• Cooling channels inside the die help rapidly bring the metal below its solidification point.
• It takes just seconds for the medal shape to solidify while maintaining crisp edges and fine surface relief.

The quick turn-around between injection and demoulding makes zinc alloy die casting ideal for both large and medium production runs.

Trimming and Deburring: Achieving a Flawless Finish

After ejection from the die, each medal has excess metal, or “flash,” at parting lines or vents. Skilled techs use trimming presses, deburring wheels, or shot blasting to remove these unwanted bits:

• Edge flash is sheared away cleanly, preventing sharp or uneven borders.
• Further inspection checks for pits, bubbles, or incomplete filling—critical for customer satisfaction and safety.
• Some medals undergo tumbling or vibratory finishing for a uniform texture before moving on to surface treatment.

Gairun’s multi-point quality checks ensure every medal meets tight appearance standards, ready for the next step—finishing and assembly.

Surface Finishing: Turning Blanks into Showpieces

Raw die-cast zinc medals are functional, but finishing brings them to life. Here are the most popular options:

1. Electroplating: Covering the surface with a thin metal layer—such as antique gold, nickel, gunmetal, black—or even rose gold or chrome for premium looks.
2. Color Filling: Soft or hard enamel, matched to Pantone colors, adds vibrant detail for logos, flags, or event themes. Controlled fill depth enhances visual impact and durability.
3. Epoxy Domes: A clear, protective resin can seal in color and provide a glassy finish with extra scratch resistance.
4. Sandblasting/Brushed Effects: Adds texture or contrast by masking and blasting select areas before or after plating.
5. Polishing: Creates mirror or satin finishes, highlighting raised or sunken surfaces and adding sophistication to commemorative medals.

Assembly and Quality Assurance

With finishing complete, medals move to assembly. Here, the correct ribbons, split rings, or custom accessories are attached based on event requirements. Careful packaging—ranging from OPP bags to velvet-lined presentation boxes—adds a final premium touch.

Quality control isn’t just visual. Advanced checks may include:

• Dimensional tolerances: Checked within ±0.1 mm for fit and relief.
• Plating thickness: Tested with XRF to confirm minimum microns, ensuring lasting luster.
• Color matching: ΔE readings compare actual colors to Pantone standards for branding consistency.
• Corrosion resistance: Salt spray testing (up to 48 or 96 hours; ASTM B117) verifies medals remain bright and free of tarnish long after the event.
• Compliance: Medals intended for children or close skin contact undergo EN 1811 nickel release testing for EU markets, or follow CPSIA requirements for the US.

How Zinc Alloy Die Casting Works for Custom Medals

The complete zinc alloy die casting process for custom medals can be summarized in several precise stages:

1. Design & Molding: Translating your logo and requirements into a precise steel die using CAD, CNC machining, and hand polishing.
2. Alloy Melting: Preparing high-grade zinc alloy with certified chemistry and quality control for strength, ductility, and compliance.
3. Die Casting Injection: Forcing molten zinc under high pressure into the die cavity, ensuring accurate and repeatable medal shapes.
4. Rapid Cooling: Heat is quickly drawn away, solidifying the medals and making them ready for demoulding within seconds.
5. Trimming & Cleaning: Removing flash and burrs, with precision inspection at every stage.
6. Finishing: Adding plating, enamel color, sandblasted textures, or custom printing according to your brand vision.
7. Assembly & QC: Attaching accessories and packaging, followed by thorough checks for durability (plating), dimensional accuracy, and color consistency.

The result is a custom medal with crisp detail, lasting finishes, and real brand impact—ideal for any event with high standards.

Die-Cast vs. Stamped Medals: Which Is Best?

While zinc alloy die casting is known for intricate designs and robust medals, metal stamping (or pressing) remains popular for certain needs. Here’s how the two compare:

If you need bold 3D relief, irregular shapes, or premium finishes, die casting is unbeatable. Stamped medals work best for quick runs, flat designs, or simple 2D logos.

• Die casting: Flagship events, custom branding, collector’s editions, or when medal texture and depth matter.
• Stamping: Budget-conscious, basic medals for schools, clubs, or mass participation where fast turnaround trumps customization.

Expert takeaway: Die casting shines when your medals must stand out for years in displays, while stamping fits quick, functional awards with tight budgets or deadlines.

When Buyers Should Choose Die-Cast Medals

You should select zinc alloy die-cast medals if your event calls for:

• Detailed, multi-level relief or full 3D modeling (e.g., mascots, portraits, landscapes).
• Durable, chip-resistant plating or custom color (especially sports, outdoors, or keepsake use).
• High-gloss, matte black, or specialty finishes matching your brand.
• Complex or non-traditional shapes that stamping and etching cannot create.
• Batches above 500–1,000 pieces for best cost-effectiveness.

Gairun works closely with B2B buyers to align every specification for outcome-driven value: from global marathons to exclusive promotional campaigns, their process ensures swift lead times, precise craftsmanship, and repeatable results.

Business Gains of Zinc Alloy Die Casting for Custom Medals

Zinc alloy die casting offers clear advantages for organizations demanding durability, prestige, and low per-piece cost at scale. Here’s how it directly benefits your bottom line and branding:

• Consistency: Automated processes make every medal match, ideal for bulk giveaways or highly visible events.
• Freedom in Design: Go beyond basic—bold 3D, cut-outs, color zones, or mixed media ad-ons.
• Longevity: Plating and color fill methods resist tarnishing, scratching, and fading throughout years of display or wear.
• Speed at Scale: Once the die is made, expect quick runs and minimal defects—even for tens of thousands of medals.
• Global Compliance: Medals meeting safety, chemical, and child-use standards give peace of mind and open doors to international events.

Medals reflect your event’s quality and legacy. With the right process, your recipients will cherish them for years, reinforcing your brand and mission long after the last race ends.

Frequently Asked Questions

What is the typical thickness for zinc alloy die-cast medals?

Most zinc alloy die-cast medals range from 2.5 mm to 5 mm thick, balancing strength and visual impact while staying comfortable to wear and cost-effective for shipping.

How does die casting ensure detail and design accuracy?

High-pressure injection reproduces every line, logo, or relief in the steel die, while tight mould tolerances and cooling control ensure medals consistently match the original design.

Are custom die-cast medals safe for sensitive skin?

Yes, reputable manufacturers like Gairun comply with EN 1811 nickel release limits and can provide RoHS or REACH certificates for medals intended for wearable or children’s use.

How do production costs compare between die-cast and stamped medals?

Die-cast medals are more cost-effective at higher volumes or with complex designs, while stamping fits low-budget, simple 2D medals, especially in smaller batches.

What’s the minimum order quantity (MOQ) for custom zinc alloy die-cast medals?

MOQ often starts at 300–500 pieces due to the upfront die cost, but unit price drops quickly with larger quantities, making it suitable for big events or multiple award categories.

Which finishes last longest on zinc alloy medals?

Electroplated finishes such as antique gold or nickel offer the best combination of brightness and durability, with salt-spray ratings up to 96 hours for corrosion resistance.