Precision Casting Process Explained: How to Improve Casting Accuracy?

1. What is Precision Casting?

Precision casting, also known as investment casting or lost-wax casting, is a manufacturing process to produce complex metal parts with high dimensional accuracy (up to ±0.1mm). It is widely used in aerospace, medical implants, and automotive industries.

2. 7 Key Steps in Precision Casting

1. Wax Pattern Making

• Inject molten wax into aluminum molds to form replicas of the final part.

2. Assembly & Coating

• Wax patterns are assembled into a "tree" and dipped in ceramic slurry to build a shell.

3. Dewaxing

• The shell is heated to melt out the wax, leaving a hollow ceramic mold.

4. Shell Firing

• The mold is sintered at 1,000°C to strengthen it.

5. Metal Pouring

• Molten metal (e.g., stainless steel 316L) is poured into the ceramic mold.

6. Cooling & Removal

• After solidification, the ceramic shell is broken away.

7. Finishing

• Cut off gates, polish, and apply heat treatment if needed.

3. How to Achieve ±0.1mm Tolerance?

• Material Selection: Low-shrinkage alloys like Ni-based superalloys.

• Process Control: Stable pouring temperature (±5°C) and vacuum casting for fewer defects.

• Inspection: Use CMM (Coordinate Measuring Machine) to verify dimensions.