There are many methods in composite product manufacturing. Generally, prepreg hand lay-up method, wet hand lay-up method, hot press, vacuum bagging method, autoclave method, fiber wrapping method, resin transfer molding method etc. methods can be given as examples. For production using prepreg, it first starts with the selection of fabrics. At this stage, where fabrics generally consist of glass or carbon fibers are selected, fabric weight and weave are determined according to the use.
The resin system is selected according to the process and properties based on the application to be used in the prepreg. Autoclave, hot press and vacuum methods can be used as processes to produce parts. Resin systems are developed to meet special performance requirements such as low temperature curing, fire retardancy and high toughness. The selection of the prepreg part production method should be made depending on the requirements of the application. For the production of simple and fast parts, the hot press method can be preferred, while for the production of more complex parts, the vacuum or autoclave method can be preferred.
Hot press is the simplest and most common method used to produce parts from prepreg. In the hot press method; the prepreg is cut to the appropriate thickness before being placed in the mold. After the prepreg is placed in the mold, it is pressed with a press. The hot press method is a widely used process in the industry and brings many advantages. This method can be used effectively in the production of high strength and lightweight parts. In addition, the controllability of the process increases the consistency of the parts and increases production efficiency.
The advantages of the hot press method are: It is a simple and fast method, low cost.
The disadvantages of the hot press method are: The air in the mold cannot be completely evacuated during the curing of the prepreg. This can negatively affect the quality and strength of the prepreg.
Autoclave is the most advanced method used to produce parts from prepreg. In this method, the prepreg is placed in a mold and then cured under high temperature and pressure with the help of an autoclave. The autoclave provides the necessary temperature and pressure for the prepreg to cure. In the autoclave method; the prepreg is cut to the appropriate thickness before being placed in the mold. After the prepreg is placed in the mold, it is cured under high temperature and pressure with the help of an autoclave. The autoclave usually operates at a temperature of 180 to 220°C and a pressure of 10 to 20 bar. The prepreg is cured and hardened in the autoclave.
The advantages of the autoclave method are:During the curing of the prepreg, the air in the mold is completely evacuated. This increases the quality and strength of the prepreg. The temperature and pressure required for the curing of the prepreg are precisely controlled by the autoclave. This allows the prepreg to cure more homogeneously.
The disadvantages of the autoclave method are: It is a more complex method than the hot press and vacuum methods. It is more costly.
Vacuum is another method used to produce parts from prepreg. In this method, after the prepreg is placed in a mold, the air in the mold is evacuated with the help of a vacuum pump. Vacuum completely evacuates the air in the mold during the curing of the prepreg, thus increasing the quality and strength of the prepreg. In the vacuum method; the prepreg is cut to the appropriate thickness before being placed in the mold. After the prepreg is placed in the mold, the air in the mold is evacuated with the help of a vacuum pump. Under vacuum, the prepreg is cured and hardened.
The advantages of the vacuum method are:Prepreg curingThe air inside the mold is completely evacuated during the process. This increases the quality and strength of the prepreg.
The disadvantages of the vacuum method are: It is a more complex method than the hot press method. It is more costly.
