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Vacuum casting is a replication technique used in the production of small series of working parts. It is an absolute turnkey answer if you want to create master patterns and copies of cast depending on the CAD designs. This produces high-quality molds that have a good finish and with less deviation from the original design. The internal hollow of the molds holds the shape of the casting because of the forces created by the vacuum pressure. This process was the invented in Japan in the 1970’s.

How Vacuum Casting Works

Vacuum casting or vacuum pressure casting (VPC) should be appropriately referred to as vacuum assist direct pour. It uses a vacuum and gas pressure to redefine the casting quality and minimize absorbency. The VPC machine typically consists of a lower and an upper chamber. The upper chamber is also the melting chamber, which houses the crucible. The lower casting chamber houses the investment mold. These two chambers are connected with a small hole that has a stopper. The vacuum is dragged in the lower chamber while, on the other hand, the pressure is employed in the upper chamber. At this point, the stopper is disengaged.

This whole mechanism creates the perfect pressure differential to fill the molds. Usually, the materials used for vacuum casting process are super alloys and the nickel-based alloy. Most common applications of this process are on turbocharger products and manufacture of gold and silver jewelry.

Modern Applications of Vacuum Casting

In today’s manufacturing industries, it is a common practice to use vacuum casting as a copying procedure in the production of small functional parts in small quantities. It is the fastest mode of producing high-quality prototypes and finished products using two components – silicone and polyurethane molds.

In vacuum casting, the process starts with the production of a master model. This is produced with the use of stereo lithography or laser sintering in a high-quality finish. The silicone is then cast around the master copy, creating the silicone mold under fractional vacuum thereby eluding air bubbles. After curing the mold, this silicone mold is cut according to specified parting planes. A cavity is formed to reproduce copies when the master copy is removed.

Why Pick Vacuum Casting?

Polyurethane vacuum casting produces high-quality models and a small number of parts that can be formed from silicon mold which are less expensive. The products produced from these molds have great finishes and does not deviate from the original pattern.

Vacuum casting has many advantages over other forms mainly because of the low cost of molds. These molds can be manufactured fast. There are also may type of polyurethane materials available for use in casting. Another advantage of this technique is the product. Most of the cast copies have an excellent surface finish and are highly accurate.

Most of the vacuum cast reproductions are also ideal for pre-launch product testing, small quantities of housing and covers, and concept models and prototypes. They are also suitable for function testing, final parts in partial quantities and for marketing purposes.