Shenzhen Alu Rapid Prototype Precision Co., Ltd.

In investment casting, vacuum is applied in different ways depending on the specific process variant, and the level varies accordingly.

Vacuum-Assisted Investment Casting (Common for Jewelry and General Precision Casting)

This uses vacuum primarily to degas the investment slurry, assist mold filling, or reduce porosity.Typical vacuum levels are near full vacuum (around 29 inches of mercury, or ~25–30 inHg), which corresponds to very low absolute pressure (close to 0–50 mbar or torr).This is achieved with tabletop or benchtop vacuum pumps during investing or pouring to remove air bubbles and improve metal flow into thin sections.

Full Vacuum Investment Casting (for Aerospace Superalloys, Titanium, etc.)

Melting and pouring occur entirely under vacuum (often vacuum induction melting, or VIM) to prevent oxidation and gas porosity in reactive/high-performance alloys.The chamber is pumped down to high vacuum levels, typically 0.1 to 10 mbar absolute pressure (equivalent to ~0.075 to 7.5 torr, or "low micron level" in some descriptions, where 1 micron = 0.001 torr).This low pressure degasses the molten metal and ensures complete mold filling without air entrapment.

Countergravity or Low-Pressure Vacuum Variants

Some processes apply a partial vacuum or pressure differential (e.g., 3.5–30 inHg vacuum, or ~100–900 mbar absolute) to draw metal upward into the mold.The exact vacuum depends on the alloy, part complexity, and equipment—higher vacuum (lower pressure) for reactive metals like titanium or nickel superalloys, and moderate vacuum assist for steels or precious metals. These levels minimize defects like porosity, oxidation, and incomplete fills while enabling intricate, thin-walled parts.