Shenzhen Alu Rapid Prototype Precision Co., Ltd.

Die casting aluminum molds (or dies) involves a precise manufacturing process to create durable, high-quality molds used for casting aluminum parts. The molds themselves are typically made from hardened tool steel, not aluminum, due to steel’s ability to withstand the high temperatures and pressures of molten aluminum. Below is a concise guide on how to create aluminum die-casting molds and the die-casting process for aluminum parts:

1. Design the Mold

Define Part Specifications: Start with the design of the final aluminum part, including dimensions, tolerances, and features. Use CAD software (e.g., SolidWorks, AutoCAD) to create a detailed 3D model of the part.

Mold Design: Design the mold with two main parts: the cavity (fixed half) and the core (moving half). Include:Parting Line: Where the mold splits.

Runners and Gates: Channels for molten aluminum to flow into the cavity.

Cooling Channels: To regulate mold temperature.

Ejector Pins: To remove the cast part.

Vents: To allow air and gases to escape.

Account for shrinkage (aluminum contracts ~1-2% as it cools) and draft angles (1-3°) 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, heat resistance, and ability to handle molten aluminum (~660°C/1220°F).

Aluminum is rarely used for molds because it lacks the strength and thermal resistance needed for repeated casting cycles.

3. Manufacture the Mold

CNC Machining: Use precision CNC machines to mill, turn, and grind the steel into the mold’s shape based on the CAD design. This ensures tight tolerances (often ±0.01 mm).

EDM (Electrical Discharge Machining): For intricate details or complex geometries, use EDM to erode the steel with electrical sparks.

Heat Treatment: Harden the mold (e.g., to 45-50 HRC) to withstand thermal and mechanical stresses.

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

4. Assemble and Test the Mold

Assemble the mold components (cavity, core, ejector pins, etc.) and mount them in a die-casting machine.

Conduct trial runs with molten aluminum to test for defects, such as incomplete fills, flash, or surface imperfections. Adjust the mold design if needed.

5. Die Casting Process for Aluminum Parts   Once the mold is ready, use it in the die-casting process:Hot Chamber or Cold Chamber: Aluminum die casting typically uses cold chamber machines because aluminum’s high melting point (~660°C) is too hot for hot chamber systems.

Melt Aluminum: Heat aluminum alloy (e.g., A380, A356) to its molten state in a furnace.

Inject Molten Metal: Inject the molten aluminum into the mold under high pressure (10,000–30,000 psi) using a plunger in the cold chamber machine.

Cool and Solidify: Allow the aluminum to cool and solidify in the mold (cooling channels help regulate temperature). This takes seconds for small parts.

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

Trim and Finish: Remove excess material (flash, sprues) and apply post-processing like machining, polishing, or coating if needed.

6. Maintain the MoldRegularly clean the mold to remove residues.

Inspect for wear, cracks, or erosion, especially after thousands of cycles.

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