Vacuum CastingServices Near You

Here at JCAD-Inc., we can provide cost-effective casting of polyurethane and urethane products and rapid prototyping of parts using short run, low-volume manufacturing processes.

What Is Vacuum Casting?

Industrial parts manufacturing can be a tricky business due to the complexity of parts and a high cost of production for standard manufacturing processes. The invention of vacuum casting was a successful attempt at solving these problems.

Vacuum casting — also sometimes called urethane or polyurethane casting — refers to a manufacturing process where a cast of an object is made using a silicone mold and casting equipment. Injection molding, a similar process, differs by having the liquid materials for casting pushed into the mold via a screw, rather than being pulled in via suction or negative pressure. Vacuum casting works differently from injection molding, mainly in the mold material used – silicone molds for vacuum casting and metal molds for injection molding. Vacuum casting is excellent for making short-runs of high quality prototypes.

A primary benefit of using a vacuum chamber is its removal of air bubbles that can alter the fine details of the finished product in other manufacturing processes. The vacuum casting process, therefore, is a good technique for rapid prototyping and manufacturing of products with fine details.

The process starts with the creation of a master pattern of the object that will be used to form the silicone mold using a casting box and liquid silicone. After the mold is formed, it is used to create casts of the master pattern inside a vacuum casting machine with the desired polyurethane or urethane resin.

A vacuum casting machine. Image by Lukadent, CC BY-SA 3.0

Vacuum casting materials

Vacuum casting requires a casting box, liquid silicone, a casting machine, and casting resins.

Unlike cast parts made from a polyurethane or urethane liquid material, the master model used in the vacuum casting service can be made from a variety of materials and methods including CNC machining. These materials may or may not need post processing.

Several vacuum casting resins are commercially available to fit the surface texture and hardness your product requires and include rubber-like polyurethanes, ABS-like polyurethanes, PE/PP-like polyurethanes, etc.

The structural qualities of your desired product will dictate the type of polyurethane we use in creating your products.

Applications For Our Vacuum Casting Service

There are many applications vacuum casting. At J-CAD Inc. we have clients from many different industries including. Some examples of prototyping applications for these industries are below. This is, however, just a small selection, the possibilities for short-run production are almost endless;

• Aerospace: Brackets, handles, turbine parts
• Architecture: Sculptures, artistic elements
• Automotive: Handles, grills, reproducing out of stock parts
• Medical: Surgical models, equipment parts
• Consumer products: Prototypes of household goods, tools, etc.
• Oil and Gas: silicone rubber parts, fluoropolymer parts, etc.

What Are the Advantages of Vacuum Casting?

• Low cost for molds
• Reduced lead times, which mean you can get your products to market faster
• Many types of polyurethane resins are available for casting, including over-molding with two or more materials.
• Coloring pigments can be added to the polyurethane resins. We can even make completely transparent or partially transparent parts depending on the casting material used.
• Cast copies are highly accurate with an excellent surface finish superior to injection molding.
• Molds are durable for 20 or more copies
• Perfect for engineering models, samples, rapid prototypes, bridging processes to mass production
• Eco-friendliness

Should I Choose Vacuum Casting or 3D Printing?

Why should you use polyurethane casting for your parts instead of 3D printing them? 3D printing is good for one-off, smaller parts or protoypes. Vacuum casting is the manufacturing process of choice however, when the product requires rapid replication on a short-run basis, which is both affordable (for short runs) and precise. 3D printing can be a good option for making master patterns.

Additive manufacturing is limited by the size of the printer bed. With casting, the maximum volume and maximum part dimensions are limited only by the size of the vacuum casting chamber.

Are There Any Cons or Drawbacks of vacuum casting?

Although a very efficient process, vacuum casting has a few disadvantages which might make you choose a different manufacturing technique;

• Vacuum casting uses silicone molds, which are prone to wear and tear and have a relatively short production lifespan.
• The mold life is limited to about 40 to 50 molds, so its application is limited to low-volume production
• The molds require regular cleaning
• Silicone molds undergo shrinkage (at a rate of about 1% to 4%) due to thermal expansion. This calls for the usage of high-quality silicone with lower shrinkage rates when making the molds

How much does a vacuum casting service cost?

Vacuum casting is a cost-effective manufacturing method. Compared to injection molding, it is relatively cheap. However, the cost of vacuum-casted parts will vary depending on what stage of the process you are at (eg. do you also need CAD design or a master pattern created?), the complexity of the design, and the volume of production.