Permanent Mold Aluminum Casting: When to Use Gravity Casting

# Permanent Mold Aluminum Casting: When to Use Gravity Casting

Permanent mold casting, gravity die casting and gravity casting commonly describe the same basic route: molten metal fills a reusable metal mold under gravity rather than high-pressure injection.

Process overview

The supplier prepares and preheats the mold, pours the specified alloy, controls filling and solidification, removes the casting, trims it and completes the agreed downstream operations. Cores, slides, risers and local cooling are selected from the drawing.

When buyers evaluate permanent mold casting

The process is often evaluated when a program needs:

• •reusable tooling for repeat production;
• •A356, ZL114 or another heat-treatable alloy;
• •mechanical properties and dimensional repeatability suited to the drawing;
• •casting plus CNC machining, heat treatment or finishing;
• •project-defined material, dimensional and pressure-tightness records.

It may be less suitable when a very low-volume prototype is better served by sand casting, or when a thin-wall, very high-volume geometry is better suited to HPDC. Process selection remains drawing-dependent.

Size, quality and porosity

Maximum size depends on geometry and tooling. Bohua can evaluate gravity-cast parts up to approximately 2 m, subject to drawing review.

Permanent mold casting does not guarantee zero or near-zero porosity. Gating, feeding, alloy preparation, solidification control, heat treatment, machining exposure and inspection all influence the result. Acceptance criteria belong in the drawing and control plan.

Pressure-tightness requirements

Bohua has its own pressure-tightness testing workshop. Test method, medium, pressure, duration and acceptance criteria are defined according to customer drawings and project requirements.

Inspection plans may use 100% inspection for some characteristics and an agreed sampling plan for others. Inspection equipment is calibrated annually.

Tooling, MOQ and documentation

Bohua's confirmed tooling-to-T1 reference is 45 days standard and 35 days expedited. MOQ is generally 500 pieces and may be negotiated for larger or higher-value parts after drawing review.

For automotive and other qualified programs, Bohua can provide PPAP documentation up to Level 5 according to project requirements, with heat and serial traceability available.

Quality-system status

Bohua Casting operates under an NQA-certified IATF 16949 quality management system. ISO 9001 requirements are incorporated within the IATF 16949 system; Bohua does not currently hold a separate ISO 9001 certificate. ISO 14001 certification is under application.

RFQ checklist

Send:

• •revision-controlled 2D drawing and 3D model;
• •alloy, temper and mechanical-property requirements;
• •annual volume and release quantity;
• •machined datums, bores, threads and sealing faces;
• •heat treatment and finishing scope;
• •inspection, pressure-tightness and traceability requirements;
• •destination, Incoterm and target T1 timing.

Request a drawing-based gravity-casting review.