Core Differences Between LPDC, Gravity, and CPC Aluminum Casting Molds

Core Differences Between LPDC, Gravity, and CPC Aluminum Casting Molds

• Gravity relies on natural flow. Gravity casting molds utilize a 1G gravitational force. Molten metal fills the cavity without external pressure, making it suitable for simple geometries.
• LPDC uses bottom pressure. LPDC molds apply 0.02-0.05 MPa pressure. This pushes metal upward, reducing turbulence and improving wall thickness consistency in wheels.
• CPC applies dual-chamber pressure. CPC molds operate at 0.2-0.6 MPa. Both the furnace and mold cavity are pressurized, minimizing gas porosity in thick sections.
• Filling speed varies significantly. Gravity filling takes 5-10 seconds. LPDC reduces this to 3-7 seconds, while CPC requires precise control to prevent premature venting blockage.
• Venting design is critical in CPC. CPC molds require specialized venting plugs. High back-pressure reduces venting rates, sometimes causing a 12-second delay in filling time.
• Riser design differs fundamentally. LPDC uses standard risers. CPC molds integrate compressed air pipes directly into the riser cavity top for localized extrusion.
• Tooling complexity increases with pressure. CPC molds require higher-grade hot-work steel. The 0.6 MPa pressure demands 15% thicker mold plates than standard LPDC tooling.
• Solidification feeding is pressure-driven. CPC applies continuous extrusion during solidification. This local extrusion transmits pressure to far-end defect positions effectively.

• Q: What is the main advantage of CPC over LPDC?
  A: CPC provides dual-chamber pressure, eliminating gas porosity in complex structural parts.
• Q: Does gravity casting use external pressure?
  A: No, gravity casting relies solely on 1G gravitational force for mold filling.
• Q: What pressure range does LPDC typically use?
  A: LPDC typically applies 0.02 to 0.05 MPa of bottom pressure during casting.
• Q: Why is venting harder in CPC molds?
  A: Chamber back-pressure reduces the venting rate, requiring specialized venting plugs.
• Q: Which process is best for aluminum wheels?
  A: LPDC is the industry standard for aluminum wheels due to balanced cost and quality.
• Q: How does CPC feed distant defects?
  A: CPC uses compressed air in the riser to create local extrusion during solidification.