Vacuum Casting or Urethane Casting: Ultimate Guide
Vacuum casting is a very common method of creating parts in low volume and attaining the quality of injection molded components.
The guide below captures information regarding the process of vacuum casting, its benefits, and the suitable material.
So, let's read and learn about it.
What is Vacuum Casting or Urethane Casting?
The process of vacuum casting is also called urethane casting, which involves pouring the urethane resin into the space between the halves of two silicon molds.
The vacuum chamber allows the extraction of the air out of the mold so that the appropriate shape of the component is achieved.
Vacuum casting is commonly used for manufacturing components of plastic and rubber as it is a very affordable and quick method compared to injection molding.
Moreover, in shorter production runs, a limited quantity of products and prototypes can be manufactured.
The casting created from the vacuum casting process offers to be bubble-free, accurate, and high quality.
Benefits of Vacuum Casting
The vacuum casting process comes with ample benefits and, hence, is a commonly selected method of manufacturing products. Some of these benefits are as follows:
- Vacuum casting allows the manufacturing of products that have fine details and high precision.
- Parts manufactured using vacuum casting offer accurate dimension stability, and hence, the components manufactured through this process end up fitting perfectly.
- The process uses silicon molds, which are not very costly, and hence, the process itself is cheap.
- The lead time of vacuum casting is less, and the products can easily be made in a few days.
How Does Vacuum Casting Work?
The process of vacuum casting involves some crucial steps that allow the manufacturing of the castings. These steps are as follows:
1. Creation of Main Model
The first stage is creating the model with the help of CAD design, and the model should be able to withstand temperatures of up to 40 degrees centigrade.
These models are mostly manufactured with the help of 3D printing or CNC machining due to their high accuracy and precision.
2. Creation of Mold
The second stage is creating the mold. To create the mold, liquid silicon is used. Then, it is poured into the casting box, which is around the main model.
Silicon is then left for curing in the oven for about 16 hours. When cured, the master mold is removed, and a cavity is achieved as originally made of silicon.
3. Creation of Cast Copies
The final stage consists of pouring liquid polyurethane into the silicon model created and allowing it to be placed in a vacuum chamber so that the liquid bubbles can be removed.
When the parts are opaque, the chamber is subjected to pressure. Then, when clear parts are required, the chamber is evacuated so that the air bubbles can be removed.
As soon as the silicon molds are separated, the new product or component is taken out.
Urethane Casting vs. Alternatives
When it comes to comparing the urethane casting with some alternatives, you can check the comparison below:
Vacuum Casting vs. Injection Molding
When comparing vacuum casting and moldagem por injeção, the process of injection molding creates components by applying a high amount of pressure on the molten material that is present in the metal mold.
Whereas the silicon molds used in vacuum casting do take a shorter time to be created. They are suitable when low production volume is required.
Moreover, the cost of tooling in injection molding is very high, which is not the case in vacuum casting because silicon molds do not cost much and can be created flexibly with modifications.
Vacuum Casting vs. 3D Printing
Impressão 3D is a technique of manufacturing components by adding layers of material, it creates complex components and is faster and adaptable.
However, when it comes to making copies of the components the process of 3D printing takes more time and hence the cost also increases.
Vacuum casting, on the other hand, also takes some time to create the master model. But once it is created, the copies can be manufactured very quickly. These copies of components are uniform and have excellent surface finish.
Materials of Vacuum Casting
There are multiple types of vacuum casting materials. Each type has its flexibility, hardness, elasticity, and other properties which make them suitable for the process.
Some of the materials that can be chosen for vacuum casting are the following:
- Vacuum casting resin is quite similar to plastic ABS.
- Glass-filled nylon is also opted for vacuum casting for components that need stiffness.
- TPE is used in components like wearables, hand grips, buttons, etc, with vacuum casting.
- Acrylic offers UV resistance and transparency and, hence, is suitable for vacuum-casted components.
- Silicon rubber has an excellent molecular structure. It is shrink-free and has a highly durable structure which makes it suitable for the vacuum casting process.
Applications of Vacuum Casting
The applications of vacuum casting are observed in many industries, and some of these are given below:
Indústria aeroespacial
Aircraft components that require precision can be made with a vacuum casting process so that high accuracy and precise detailing in the components can be achieved.
Some of these parts consist of air ducts, fuel systems and some exterior components.
Indústria automóvel
The automobile industry is highly dependent on the vacuum casting process for the protection of car parts like sensors, rotors, and many more.
Also, the low-volume car components like engine covers, handles, and dashboards are also manufactured through vacuum casting.
Indústria médica
In the medical industry, rapid prototyping is very crucial and vacuum coating offers quick prototypes for various medical equipment.
It also helps create dental implants and prosthetics for patients on an individual basis according to their specifications.
Indústria de bens de consumo
Everyday consumer products like accessories, household appliances, electronics, baby products and toys are also manufactured with the help of vacuum casting, as it helps to create prototypes for these.
The vacuum-casted prototypes are tested and verified. Once approved, the final products are made using injection molding.
Conclusão
Vacuum casting process is one of the quickest and most affordable processes.
If you are also looking for products and prototypes of components for your applications, you can contact DEK and get them manufactured through vacuum casting.
We offer custom vacuum casting products designed based on your specifications.
FAQs
What are the limitations of vacuum casting?
Vacuum casting is suitable for some types of materials only. The quality of the product may have an impact if the mold is opted for. Some materials are subject to shrinking and may make the components either too thin or too thick.
How expensive is vacuum casting?
Vacuum casting is not very expensive when compared to other methods of manufacturing. Once the mold is ready, it can be used again and again for manufacturing products.
What products are made from vacuum casting?
Vacuum casting helps produce a wide range of products like electronics, medical implants, medical tools, engine components of a car and many more.
