What is vacuum casting?

Introduction

If there is a processing technology that can replace injection molding for prototypes or small batches, then vacuum casting must be the best economic alternative. Vacuum casting is particularly useful in industries that require fine and precise components. 

It is an advanced manufacturing technology that uses silicone molds to make replicas of objects. With the support of this technology, the goal of producing high-quality prototypes and small batches of parts can be achieved quickly and economically.

This blog will delve into the details of vacuum casting, its workflow, types, materials, etc. Let you understand this special process of vacuum casting.

What is vacuum casting?

Vacuum casting is a silicone manufacturing process. Almost all vacuum casting parts are formed without silicone molds, so vacuum casting is also called "silicone casting". During the vacuum casting process, a specific silicone vacuum mold is used to suck the mixed raw material liquid into the mold cavity to manufacture the required custom vacuum casting parts.

This manufacturing technology is particularly suitable for the production of small and medium-sized batches of parts with complex geometries and fine details. Therefore, it is often used for prototyping and testing before mass production, allowing designers and engineers to quickly and cost-effectively evaluate the rationality of the designed parts.

What is the workflow of silicone vacuum casting?

The workflow of silicone vacuum casting usually includes the following key steps:

1. Master model creation: According to the shape of the part, create a master model of the required part. This model is divided into a negative mold and a positive mold. The creation of the model generally uses two technologies, CNC machining and 3D printing.

2. Mold making: Encapsulate the master model in silicone to create the mold shape of the custom part.

3. Preparation: This step is very important. Make sure that the mold surface is free of impurities or oil, and then prepare the mold work by using a release agent to ensure easy removal of the final part.

4. Material mixing: Mix the selected casting material (usually polyurethane (PU)) thoroughly.

5. Vacuum filling: Pour the liquid material into the mold under vacuum conditions to eliminate bubbles. In this process, the casting materials should be mixed in proportion and stirred evenly before pouring into the vacuum silicone mold. 

If the liquid material is poured into the silicone mold without stirring evenly, the effect of eliminating bubbles will not be so ideal.

6. Curing: Only after a period of curing treatment can it solidify into the desired part shape.

7. Demolding: After curing, carefully remove the part from the silicone mold. In this process, a little carelessness will cause damage to the parts or even the mold.

8. Finishing: Perform any necessary trimming, grinding, or surface treatment. Vacuum-casting parts that have been finished will have a significant improvement in surface quality and accuracy.

What are the types of silicone vacuum casting?

There are many types of silicone vacuum casting processes, including:

● Standard vacuum casting: A basic technique for making parts using standard silicone molds and polyurethane materials.

● Color casting: Based on classic vacuum casting, pigments or dyes are added to the casting material to achieve aesthetic effects.

● Composite casting: Use reinforcements to increase the strength and durability of parts.

● Transparent casting: Use transparent resin to make transparent or translucent parts.

From the above processes, we can see that these types of vacuum casting will form different vacuum-cast parts due to the different colors and materials used.

What materials can be used for silicone vacuum casting?

Many materials can be used for silicone vacuum casting, including:

● Polyurethane (PU): The most common choice due to its versatility and wide hardness range.

● Silicone resin: Used for applications that require flexibility and high-temperature resistance.

● Epoxy resin: Suitable for applications that require high strength and chemical resistance.

● Thermoplastics: Some thermoplastics can also be cast using silicone molds. For example, our common ABS, PS, TPV, etc.

What surface treatment processes can be used for silicone vacuum casting?

Many surface treatments can enhance the finish of vacuum cast parts, including but not limited to the following:

● Painting: A common surface treatment process that adds color to the surface of vacuum cast parts to make the parts aesthetically pleasing and protective.

● Polishing: This surface treatment process can give parts a smooth, shiny surface.

● Coating: Powder coating is a surface processing process used to enhance the durability of parts.

● Texturing: This is a process that creates a specific surface texture for aesthetic or functional purposes.

What processes are similar to silicone vacuum casting?

Similar processes to silicone vacuum casting include:

● 3D printing: Both methods (SLA and SLS) are used for rapid prototyping, but they differ in material application and finish.

● Resin casting: Resins provide a wider category that includes various casting techniques using resins.

● Injection molding: Mainly used for large-scale production, and the object of injection molding material is rigid molds rather than flexible silicone.

Do you provide vacuum casting services?

Yes, we offer vacuum casting services worldwide, including mold making, material selection, and finishing services. If you are looking for a vacuum casting manufacturer that can help you efficiently transform your designs into functional prototypes or low-volume production parts, we are your best choice.

Simply upload your drawing files, and our experienced quotation engineers will provide you with a free quotation service. At the same time, you can communicate in detail about your project through our online chat function or with our sales team.

Summary

Vacuum casting is a powerful and efficient manufacturing technology that can quickly produce high-quality prototypes and low-volume parts. Its ability to accurately create complex designs makes it an essential tool for a wide range of industries. 

Whether you are a newcomer to the industry or an experienced designer, you will gain a lot from learning about the vacuum casting workflow through this article.

It is worth mentioning that vacuum casting is a flexible manufacturing solution. Whether you need prototypes or low-volume production, vacuum casting can meet your customized needs.