Shenzhen Alu Rapid Prototype Precision Co., Ltd.

Die casting zinc is a manufacturing process where molten zinc is injected into a steel mold (die) under high pressure to produce precise, complex parts. Zinc is ideal for die casting due to its low melting point, excellent fluidity, and corrosion resistance. Below is a concise guide on how to die-cast zinc, covering the process, equipment, and key considerations.

1. Design the MoldPart Design:

 Create a 3D model of the desired part using CAD software (e.g., SolidWorks, AutoCAD), specifying dimensions, tolerances, and features.

Mold Design: Design a two-part steel mold (cavity and core) with:Parting Line: Where the mold splits.

Runners and Gates: Channels for molten zinc to flow into the mold.

Cooling Channels: To control mold temperature.

Ejector Pins: To remove the cast part.

Vents: To allow air and gases to escape.

Account for zinc’s shrinkage (~0.7-1%) and include draft angles (0.5-2°) for easy part ejection.

2. Select Tooling Material

Use high-grade tool steel (e.g., H13 or P20) for the mold due to its durability and ability to withstand repeated thermal and mechanical stresses.

Zinc’s lower melting point (~420°C/788°F) compared to aluminum makes it less demanding on molds, potentially extending mold life.

3. Manufacture the Mold

CNC Machining: Use CNC milling, turning, or grinding to shape the steel mold to precise specifications (tolerances often ±0.01 mm).

EDM (Electrical Discharge Machining): Apply EDM for intricate details or complex geometries.

Heat Treatment: Harden the mold (e.g., 45-50 HRC) to ensure durability.

Surface Finishing: Polish or texture the mold for desired part finish and to reduce sticking.

4. Set Up the Die-Casting Machine

Hot Chamber Die Casting: Zinc is typically cast using hot chamber machines because of its low melting point. The machine has a built-in furnace where zinc is melted, and a gooseneck mechanism injects the molten metal.

Machine Selection: Choose a machine with appropriate tonnage (clamping force) based on part size and mold requirements (e.g., 20-800 tons).

5. Die-Casting Process

Melt Zinc: Heat zinc alloy (e.g., Zamak 3, Zamak 5, or ZA-8) to its molten state (~420-450°C/788-842°F) in the hot chamber furnace.

Inject Molten Zinc: Use the machine’s plunger to inject molten zinc into the mold under high pressure (1,500–25,000 psi) to fill the cavity quickly.

Cool and Solidify: Allow the zinc to cool and solidify in the mold (typically seconds for small parts), aided by cooling channels.

Eject the Part: Open the mold and use ejector pins to remove the cast zinc part.

Trim and Finish: Remove excess material (flash, sprues, runners) using trimming dies or machining. Apply post-processing like polishing, plating, or coating if needed.

6. Maintain the Mold

Clean the mold regularly to remove zinc residues or release agents.

Inspect for wear, cracks, or erosion, especially after high-volume runs.

Apply mold release agents to ease part ejection and extend mold life.