What Is V-Process Casting

V-process casting and lost foam casting are also known as vacuum casting. The name “V-process” is derived from the first letter of the English word Vacuum.

The biggest difference from traditional sand casting is that no binders are used.

In V-process casting, a plastic film is used to seal the sand flask. A vacuum system evacuates the air inside the mold, creating a pressure difference between the inside and outside of the mold. This pressure difference compacts the dry sand and forms the required mold cavity. After core setting and mold assembly, vacuum is applied during pouring so that the casting solidifies under negative pressure. Once the vacuum is released, the sand collapses and the casting is easily removed.

Advantages of V-Process Casting and Lost Foam Casting Compared with Traditional Sand Casting

High casting quality

Due to vacuum pouring, castings have fewer sand defects and gas porosity, higher density, smooth surfaces, clear contours, and accurate dimensions.

Energy-saving, efficient, and environmentally friendly production

With V-process and lost foam technologies, dry sand can be reused repeatedly without mold baking, significantly reducing coal consumption. Although continuous operation of vacuum equipment slightly increases electricity consumption, dust generation is greatly reduced, labor requirements are lowered, and labor intensity is significantly decreased. Harmful gas emissions during pouring are minimal, truly achieving environmentally friendly casting production.

Key Factors in V-Process Casting Production

The core of V-process casting lies in selecting an appropriate vacuum extraction system. When choosing a vacuum system, the capacity of the vacuum pump must first be determined, taking the following factors into consideration:

1.The size and number of sand flasks operating under vacuum simultaneously;

2.The number of molds poured at the same time;

3.The size and shape of the castings;

4.The air permeability of the mold surface adjacent to the plastic film, which controls the amount of air entering the mold through cracks in the film. Therefore, during pouring, it is necessary to apply a small amount of refractory coating to the mold, which helps provide an “auxiliary sealing layer” for the vacuum system.