How to Make the Infusion Process Correctly

 

Resin Infusion Process

 

 

Before using the vacuum infusion molding process, we first prepare the necessary auxiliary materials. If we prepare them during the production process, it will be very troublesome. After all the materials are prepared, we can start the operation.

 

 

 

This step is critical. When preparing the mold, many factors need to be considered, such as the air tightness of the mold, surface finish, cleanliness, defects, width of the mold flange, etc. The mold I chose is an epoxy system mold. Because the infusion molding process is cured at room temperature, it does not need to be cured at high temperature. This mold can withstand temperatures of 50°~60°.

 

 

We need to apply 4-6 coats of release agent to a new mold. I chose Easy-lease150 chemical release agent from Easycomposites. This release agent has a very good demolding effect and is semi-permanent, which means you don’t need to re-apply the release agent next time you make a product.

 

 

After wiping off the release agent, we can stick the sealing tape on the flange edge of the mold. Since it is cured at room temperature, low-temperature sealing tape can be selected. Another advantage of sticking the sealing tape in advance is to avoid the fiber bundle being pressed under the sealing tape during the subsequent laying process. If the fiber bundle is pressed under, it will cause the airtightness inside the vacuum bag and fail to form a vacuum state.

 

 

In this step, you can lay the layers according to the process requirements (carbon fiber cloth, glass fiber cloth, layer thickness).

 

After laying the reinforcement material, use special scissors to cut off the part that exceeds the sealing tape to avoid affecting the adhesion of the vacuum bag and wrinkles in the product area under the vacuum.

 

After cutting to size, you can use paper tape or pressure-sensitive tape to fix the fiber material, but the premise is that the reinforcement material must be completely attached to every part of the product area to avoid bridging when vacuuming.

 

 

After the reinforcement material is laid, the release cloth can be laid. The release cloth is the auxiliary material of the first isolation product. It is easy to tear off after curing and forming, and the original weaving pattern of the release cloth is formed.

 

The release cloth should be laid larger than the reinforcement material, because it will be easier to tear off the product after curing. After covering the entire product, fix it with paper tape.

 

 

The next step is to lay the guide mesh. Choose the appropriate guide mesh according to the complexity of the mold surface. If the surface is more complex, you can choose a woven guide mesh. This guide mesh is softer and easy to lay on complex areas of the mold. Because this mold is not that complicated, I chose a medium-speed guide mesh.

 

 

 

The arrangement of the guide spiral tube and the resin guide silicone seat. When guiding the resin, the spiral tube can make the resin flow quickly along the spiral tube and quickly infiltrate into the fiber layer through the guide net. After the arrangement is completed, fix it with paper tape. Special attention should be paid here to the arrangement of the silicone base. Do not lay the guide spiral tube under the silicone seat at the discharge port. Only the spiral tube is arranged at the feed port.

 

 

This step is particularly important. We need to cut a large enough vacuum bag because we need to reserve space for pleating according to the mold surface. These pleats can make the vacuum bag press down along the contour of the mold when vacuuming to avoid bridging.

 

After the vacuum bag is bonded, we can connect the vacuum pipeline. There are two silicone seats on the mold that need to be connected with PVC guide tubes, and one is connected to the resin inlet. We can use a blade to cut the silicone seat outlet, insert the guide tube into the silicone seat and seal it with sealing tape, and finally lock it with a pipe clamp.

 

 

The discharge port is connected to the resin collector. An inner tank should be placed in the resin collector to collect excess resin. Each connection port must be sealed to ensure no air leakage.

 

 

When the resin collector is connected, the vacuum pump can be connected. We insert the guide tube into the barbed joint of the vacuum pump.

 

(If you are interested in vacuum equipment, you can log in to www.easycomposites.cn to learn more. There are the equipment you need and usage information there)

 

 

When the pipeline is connected, vacuum can be drawn.

We must ensure that there is enough vacuum film in every corner of the mold surface, and every area of ​​the mold surface can fit the mold surface. Do not allow bridging to occur. If there is bridging, turn off the vacuum pump, open the pipe clamp at the resin feed port, relax the vacuum film, and then handle the bridging area until all places are completely fitted to the mold.

 

When the Pointer of the Vacuum Gauge Reaches

 

air pressure, and the sound of the vacuum pump will also change, it means that the vacuum bag cavity is already in a vacuum state. At this time, we can turn off the vacuum pump and clamp the guide tube of the resin outlet with a pipe clamp. Now we can perform a vacuum leak test. We wait for 15 minutes and always observe the pointer of the vacuum gauge on the resin collector. If there is a leak, the pointer will change. At this time, you need to check all possible leaks, such as (the bonding of the sealing tape, whether there are pinholes in the vacuum film, whether each connection port is tightly sealed, and the airtightness of the mold), etc., and test again until it is completely vacuum.

 

 

It is very important to choose a resin suitable for infusion, because you need to consider many factors, such as the resin’s wettability, viscosity, activation time, curing time, fluidity, etc.

 

I chose Easycomposites’ special infusion resin, which has low viscosity and can quickly infiltrate the entire reinforcement. The mechanical properties of this resin are also particularly excellent. At the same time, this resin matches two fast and slow curing agents, and the operating time is wide, so there is no need to worry about insufficient operating time. We turned on the vacuum pump again to ensure that there was no leakage.

 

 

The ratio of this resin is 100:30 (100g resin 30g curing agent). You can use fast or slow curing agent, or half fast and half slow, but you must mix the ratio accurately and stir it evenly. Since there will be bubbles in the resin when stirring, it needs to be left for about 5 minutes to degas.

 

At this time, we can put the guide tube of the resin feed port into the prepared resin barrel, and remove the tube clamp on the tube, so that the resin can enter the mold cavity with the vacuum pressure.

 

 

We can see that the resin quickly infiltrates into the reinforcement along the spiral tube and the guide net, and the bubbles in the resin will be gradually drawn out of the mold cavity by the vacuum pump as the vacuum pressure increases. When the resin is completely infiltrated into the product, we can clamp the feed port with a pipe clamp.

 

When the resin is completely infiltrated, the excess resin is collected into the resin collector through the work of the vacuum pump. When there is no excess resin on the silicone base at the resin feed port, the resin outlet can be clamped with a pipe clamp, that is, the pipeline connected to the resin collector. At this time, the guide has been completed, and the curing time is 24 hours at room temperature @25°, and then the mold can be demoulded.

 

Tear off the vacuum film, and the silicone base can be reused.

 

 

When tearing off the release cloth, be sure to wear protective gloves to avoid the resin fibers cutting your skin.

 

When demolding, you will find that it is easy to remove the product from the mold after wiping the Easy-lease chemical release agent.