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The Benefits of Vacuum Casting to the Prototyping Process
by Nice Rapid | Jun 22,2020 | Vacuum Casting

Are you looking for the most economical way to create your prototype? Why don’t you consider using vacuum casting?

It is a prototyping process that has only a few requirements - the right maximum temperature to cure the material and the right material. Many product developers find vacuum casting to be a cost-effective option and an ideal method for small volume production, especially for plastic prototypes.

Another good thing about vacuum casting is it has a quick cycle time compared with other prototyping processes. It also produces high-quality parts with a smooth finish. 

Read this article if you want to know more about the vacuum casting process and how it can help you with your prototyping.

Vacuum casting molds

Unmasking the Vacuum Casting Process 

As the name implies, the vacuum casting process is belonging to the casting method of manufacturing elastomer parts and products. It involves using a machine with a vacuum to draw the melted material into the mold. This process eliminates the flaw in the product because it does not entrap air bubbles in the material while curing.

This manufacturing process is favorable for designs that require elaborate undercuts and complex details. It is also recommended for molds that use reinforced wire or fiber.

Vacuum casting is also known as thermoforming because it fits the description of the process. The plastic materials are heated before pouring into the mold cavity. Preheating happens in the fully automated vacuum casting machine until the optimum heating temperature is achieved. It makes the material elastic and soft.

Other means of manufacturing can also form similar parts but many of them have air bubbles trapped inside the cured part. This reason prompts the development of the vacuum casting method to eliminate the air bubbles that affect the integrity of the product. The addition of the vacuum factor in the machine solved this problem.

The Vacuum Casting Machine

The most vital part of the vacuum casting process is the casting machine. This machine is composed of two chambers, located one on top of the other. You will normally see a pair of dies with moving plates on the top chamber. In between these two chambers is the mold cavity that has the vacuum.

The bottom chamber has a crucible which collects the resin after passing through the gating system. This gating system serves as the pathway to control the amount of resin going into the cavity and for collecting the resin in the crucible. The final product is ready after stripping the excess material.

How Does Vacuum Casting Works?

The vacuum casting process involves a three-step process in creating a part. The process may be labor-intensive because of its different stages of production but you will be amazed how fast it is. Production is also simple and straightforward, and easy for the operator to manage.

Creating the Master Model

The first step in the vacuum casting process is creating the master model. This model can be the actual part of it that can be made using different rapid prototyping methods like 3D printing or CNC machining. It has the exact shape and dimensions of the part because these specs will be taken to the next stage.

Producing the Mold

The next step in the process is creating the mold using liquid silicone. Here the master model is placed inside the casting box where the liquid silicone will be poured over. Once complete, it will be left to cure in the oven.

The cured liquid silicone mold is then cut open to remove the master pattern. Once the master pattern is removed, It will leave an empty cavity. This cavity has the exact dimensions and shape of the original pattern and is ready for the step. It is now the silicone mold that can be used between 15 to 20 times.

Creating the Casting Copies

The final stage of the vacuum casting process is the creation of the casting copies. In this step, a suitable resin or polyurethane like rubber is used. This material resembles the properties as the final product.

To know the exact resin to use, the manufacturers use the material data references. It contains all the information on the properties and composition of the material to approximate the properties of the intended part.

After preparing the right resin, it will be poured into the empty cavity to form the desired part. After the mold is filled, it will be left to cure. This is where the vacuum works as the applied pressure prevents air bubbles from forming inside the part.

How the Vacuum Casting Process is Beneficial to The Prototyping Process

Here are the reasons why vacuum casting is a good option for your prototyping requirement.

  • Reduced production cost
  • Delivers quick results
  • Excellent product quality
  • High-quality finish

Final Thoughts   

The vacuum casting process has plenty of benefits to the prototyping process. It allows for a wider choice of flexibility, hardness, and rigidity that you may want for your product. The final product has a great finish too, which adds to its preferability.

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