The-fiber-glass-mold-is-sprayed-by-fiber-glass-gel-coating-as-a-thin-layer-Vacuum Infusion Process

Vacuum Infusion Process : Carbon Fiber Manufacturing

Carbon fiber has become one of vast using material for automobile industry compared to past usage and especially in automobile sports and supercars. Using at least single part of carbon fiber material becomes trend in present luxury vehicles. Variety of design flexibility and comparatively high amount of strength to weight ratio are the predominant reasons for this trend. Therefore carbon fiber is applying for thousands of customized vehicle and related products all over the world. For manufacturing carbon fiber body panels there are number of techniques. The simplest is “hand lay-up method”. Second method is “Vacuum assisted resin infusion” and other widely use one is “Vacuum in Autoclave”. In this article it is going to describe the tactics that should remember when carrying out “Vacuum Infusion process” carbon fiber manufacturing method at prototyping and these secrets will help for fine finished surface.

The fiber glass mold is sprayed by fiber glass gel coating as a thin layer - Vacuum infusion process
The fiber glass mold is sprayed by fiber glass gel coating as a thin layer

First there should be a mold and it is the key tool for manufacturing process. Usually molds for this kind of works it is using aluminum mold or fiberglass molds and in here it has used a fiber glass mold of central battery pack of a unique electric super car, and mold can be seen in orange color in images.

For begin the process mold should be cleaned with water and after dried out it would be polished with mold wax for 5 cycles and or each cycle it should use 3 waxing cloths as number 1, 2 and 3. And then the most important part of the process it will be sprayed a “glass fiber gel coating” as a thin layer. Then this will keep for 12 hours until it is dried.

Carbon fiber mat lamination with using glue spray
Carbon fiber mat lamination with using glue spray
Vacuum Infusion Process continued…

After that it can be start the carbon fiber mat lay-up. When laminating these mats it can be use little sprayer bottle of acetone. Because when spraying this liquid, the carbon fiber mat and gel coating will be bonded together. Then other carbon fiber cloths can be laminate with glue sprayer.

It is important to laminate according to the correct order. That is thinnest mats as the first mats and thicker mats at last. In between it has to put carbon fiber core mat to strengthen the panel and for getting some holding characteristic. As a final lamination it will be use a “peel off cloth” in carbon fiber grade and this will help at the end for removing excessive resins from the panel.

Plastic net will be lay-up and above it plastic spiral would be set up for better resin flow - Vacuum infusion process
Plastic net will be lay-up and above it plastic spiral would be set up for better resin flow

This all lay-ups will be covered with a plastic net as in the image and this will helps to keep a good resin flow at the infusion process. And also it will be used plastic spiral for same reason and better if it can be taped it into plastic mat. As a next step carbon fiber silicon barbs will be placed. Finally this all set-up will be covered with polythene (vacuum bag) and with a carbon fiber sealer tape as in the image. Polythene should be in baggy way and baggy will help to shrink the polythene tightly to mold when vacuuming.

Barbs and clear hoses will be fixed through a hole of this polythene bag.

Plastic net will be lay-up and above it plastic spiral would be set up for better resin flow
Plastic net will be lay-up and above it plastic spiral would be set up for better resin flow

For the process it should be minimum 2 number of barb fitting. That is one fitting as an inlet and other one as an outlet.  Inlet hose has to be dipped into resin container after mixing but until that the hose will be blocked by using locking plier or clip. Other end has to set to the vacuum pump through the vacuum trap. Because trap will help to protect the vacuum pump from being damaged by resin. After switching on the pump the bag will start to shrink to the mold with mats like a sandwich. Better to check for a while for any leakages or drops of vacuum gauge. If there are no leaks, resin infusion can be started.

The inlet of the clear hose will dipped to the resin bucket and switch on the vacuum pump. Then remove the locking pliers and it can be seen resin is flowing through the hoses and through the mats as in the images.

After vacuum pump switch is on the polythene will be shrink into mold with sandwiching all the layers to the mold - Vacuum infusion process
After vacuum pump switch is on the polythene will be shrink into mold with sandwiching all the layers to the mold

After observing excessive resin flowing to the trap, the clear hoses would be blocked again to stop the flow by using locking pliers. Then this will be keep carefully until the part is cured. After another 12 hours it can be removed the polythene vacuum bag and peel off cloth. Then the panel and mold would keep for another 12 hours until panel will be cured completely.

Once the locking pliers released resin will flow through the mat and it can be visually inspected
Once the locking pliers released resin will flow through the mat and it can be visually inspected

When removed the part from the mold after this period it can be seen fine finished carbon fiber product that has glossy finishing. To sum up it has various methods of obtaining fine finished carbon fiber customized panels and using glass fiber thin layer method – Vacuum infusion process will be easy and worth.

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