Vacuum Casting VS Injection Molding

Last Updated on October 13, 2023 by assistant

Vacuum casting and injection molding are both popular methods of manufacturing plastic parts. We are often asked the following questions. You’ll learn more about them after reading our blog in a few minutes.

Vacuum Casting VS Injection Molding1.Is vacuum forming cheaper than injection molding?

It depends on your project. Vacuum casting, also known as vacuum forming, is characterized by forming a plastic mold within hours. Meanwhile, it takes more than a month to make an injection mold. So if you’re doing any low-volume prototyping project, vacuum forming will be more economical than injection molding. If you want to make high volume plastic parts, vacuum forming will be more expensive and time consuming.

2.What are the advantages of vacuum casting?

Vacuum casting has always been the method of choice for low-volume prototyping. It brings multiple advantages to your plastic manufacturing projects.

  1. Economic. Vacuum casting manufactures plastic parts from plastic molds. The cost of molds is much cheaper than metal molds.
  2. Rapid prototyping. Silicone molds can be made in hours.
  3. High quality. The vacuum cast prototypes are of good quality and have a good surface finish.

3.What are the limitations of vacuum casting?

You need to be aware of some limitations of vacuum casting.
1. The tolerance is not strict. Silicone molds shrink easily. The shrinkage is around 2%, which means that the tolerances for the finished plastic part are not as tight. If your project has high tolerance requirements, vacuum casting is not ideal.

2. Only suitable for small batch production. Because the life of plastic molds is very short, because a single silicone mold can only be used 20 times. The silicone mold will be deformed after 30+ times of use, which will affect the accuracy of the parts.

3. Additional assembly and simple design. Assembling the parts requires more time and effort. Also, silicone molds can only be used to make plastic parts with relatively simple designs.

4. Continuous Defects. If there is a problem with the silicone mold, it will result in an inaccurate part. At the same time, if the master is inaccurate, it can greatly affect tolerances.

5. For plastic only. The range of materials for vacuum casting is only plastic. As for metal, it requires higher temperatures to melt and form. It will greatly damage the silicone mold.