How to make carbon fiber pipes?

In addition to the strength superior to steel and the weight reduction effect of a large proportion, the surface quality and manufacturing precision of carbon fiber pipes are also important factors affecting their application effects. The commonly used manufacturing methods of carbon fiber round pipes and square pipes are filament winding method and molding-autoclave process, but the outstanding defect of using these processes is that the surface quality of the manufactured pipes is not good enough, and the prepreg lamination bag pressing process is used. Special-shaped pipes also have the same surface defect problem. Surface quality not only affects the smoothness of the appearance of the pipe, but also affects the geometric size of the pipe and the ability of mechanical equipment. Therefore, improving the quality and manufacturing accuracy of the pipe is a major difficulty in carbon fiber pipe manufacturing.

The reason for the defect:

The surface defects of the finished carbon fiber pipe fittings mainly include wrinkles, streaks and rich glue. The occurrence of these problems is mainly concentrated in the prepreg layer. When using the carbon fiber composite prepreg layer, if it cannot be applied Sufficient tension to compress the prepreg laminate will make the layers of the composite prepreg laid relatively loose, and the overall thickness will exceed the thickness of the target pipe product. Therefore, during the molding process, the general treatment method is to pressurize the composite materials of each layer and let the excess resin flow out, but this pressurization will inevitably bring two shrinkage forces. First of all, when the carbon fiber composite laminated block is compressed, the thickness of the pipe will become thinner, the outer diameter will become smaller, and the circumference will also decrease accordingly. , discount; Secondly, in the carbon fiber tube forming process, it is often necessary to use some auxiliary materials on the prepreg laminate block blank, such as air felt and vacuum bags, etc. These auxiliary materials can also cause wrinkles and streaks during compression, When cured, it imprints on the composite surface, creating wrinkles.

Combined pre-compaction and temperature control:

Based on the experience of Wuxi Weisheng New Materials, an important step to solve the surface defects of carbon fiber pipes is to combine pre-compaction and appropriate temperature control during the laying process of carbon fiber prepregs. The specific operation is in the laying process. In the process, after laying several layers, pre-compaction is carried out at a certain temperature, and a certain pressure is applied to compress each layer of fibers. This timely pre-compaction can prevent the accumulation of slack fibers. Under the process conditions of pressure and temperature, the excess resin, air bubbles and low-boiling substances in the prepreg blank are excluded, so that the blank is dense and basically reaches a predetermined thickness. The pre-compacted blank does not need to be sucked in the curing process, and the resin content in the carbon fiber composite material and the thickness of the pipe can be effectively controlled.