Vacuum injection is a manufacturing process that is becoming increasingly popular in the world of composite materials. It is a technique that provides better quality and stronger products, making it ideal for a variety of applications. But what exactly is vacuum injection? What methods are there? And what are its advantages and disadvantages? In this blog, we dive into the world of vacuum injection and explain the two best-known methods so that you can make an informed choice for your project.
Vacuum injection is a manufacturing technique in which resin (resin) is injected into a mould under vacuum. This process ensures that the resin is evenly distributed through the reinforcement material, such as glass fibre or carbon fibre. This creates a composite material with high strength and low weight. Moreover, the vacuum ensures that any air bubbles and excess resin are removed, resulting in better quality and higher strength of the final product. In this way you create a durable product with a high strength-to-weight ratio.
This vacuum injection technique is widely used in the aerospace, automotive and shipbuilding industries, as well as in construction and sports equipment manufacturing.
There are several methods of vacuum injection, of which 'Wet Bagging' and 'Resin Infusion' are the best known. We would like to explain both techniques.
Wet Bagging is a simple technique within vacuum injection. In this method, the reinforcement material is impregnated with resin beforehand and then placed in the mould. A vacuum film is then placed over the material and the whole thing is vacuumed. The vacuum ensures that excess resin and air bubbles are removed, resulting in a better quality of the final product.
Vacuum injection via the Wet Bagging method has some significant advantages over other vacuum injection techniques. We cover both the advantages and disadvantages of the technique. This can help you choose the right method for your project.
Advantages
A major advantage of Wet Bagging is its relatively simple process. This makes this method accessible to beginners and small businesses. Moreover, start-up costs are lower than for Resin Infusion. The initial investment in equipment and materials is often much lower for Wet Bagging than for Resin Infusion. Finally, Wet Bagging allows you to combine different fibres and resins, giving you more freedom in design and material selection.
Disadvantages
One of the disadvantages of Wet Bagging compared to Resin Infusion is a less uniform distribution of the resin. Because the resin is applied in advance, the distribution can be less uniform than with Resin Infusion. In addition, Wet Bagging can lead to more air inclusions, which can affect the quality of the final product.
| Advantages | Disadvantages |
| Accessible method | Less uniform distribution |
| Low start-up costs | Potentially more air inclusions |
| Flexibility | More resin consumption |
Resin Infusion is an advanced technique within vacuum injection. In this method, the reinforcement material, such as glass fibre or carbon fibre, is first placed dry in the mould. Similar to Wet Bagging, a vacuum film is then placed over it and it is drawn vacuum. This creates a pressure differential, allowing the resin to be injected evenly through the reinforcement material.
Vacuum injection via the Resin Infusion method has a number of important advantages and disadvantages. We cover both the advantages and disadvantages of this technique to help you choose the right method for your project.
Advantages
Resin Infusion has some advantages over other vacuum injection techniques. For instance, less resin is needed and the resin is evenly distributed over the fibres. This ensures lower weight and higher strength of the final product. In addition, air inclusions are prevented and this method enables precise control and optimization of the production process. All this results in a better quality of the final product.
Disadvantages
The two disadvantages of the Resin Infusion method are the high start-up costs and the complex production process. This often makes the method less suitable for beginners, as the initial costs are a lot higher compared to the Wet Bagging method.
| Advantages | Disadvantages |
| Uniform resin distribution | More complex production process |
| No risk of air inclusion | Higher start-up costs |
| Better control of the production process | |
| Less resin consumption |
As you have read above, Wet Bagging and Resin Infusion are both methods of producing fibre-reinforced products. However, there are some important differences between the techniques:
| Wet Bagging | Resin Infusion |
| Resin is applied directly to the laminate with a brush or roller and its drawn vacuum. | Resin is injected evenly onto dry laminate. |
| Resin is applied to the fibres manually. | Resin is pulled through the fibres by the vacuum process. This ensures even distribution without air entrapment. |
| Air is removed from the laminate after resin application. | Air is removed from the laminate during injection. |
| Is often applied in small projects. | Is often applied in large projects. |
As you have read, vacuum injection offers many possibilities for producing high-quality composite materials. Whether you choose the simpler Wet Bagging method or the advanced Resin Infusion technique, vacuum injection guarantees a better and stronger final product. In addition, the process is more environmentally friendly and more efficient than other production techniques. In short, vacuum injection is a promising technique that takes the world of composite materials to the next level!
Want to know more about Wet Bagging or Resin Infusion? Please don't hesitate to contact our product specialists. We are more than happy to offer free, non-obligation advice!
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