Coiled prepreg carbon fiber tube and pultruded carbon fiber tube are two common process forms of carbon fiber tube, and the two carbon fiber tubes have certain differences in finished product performance and practical application.
Coiled Prepreg Carbon Fiber Tube:
The coiled prepreg carbon fiber tube is made by using twill carbon fiber prepreg or unidirectional prepreg layer by layer winding on a metal mandrel, and then curing at high temperature. In this process, the quality control of the pipe is mainly carried out in two aspects: one is to ensure that the size of the metal mandrel must be accurate and appropriate, because the carbon fiber prepreg is wound on the outside of the mandrel, and the outer diameter of the mandrel itself needs to be the same as that of the mandrel. The inner diameter of the manufactured carbon fiber tube is matched; the second is to carefully design the lay-up scheme of the carbon fiber composite prepreg. The number of layers and thickness of the carbon fiber prepreg wound on the mandrel determines the outer diameter of the carbon fiber tube. The fibers of carbon fiber prepreg are oriented on the 0° axis (the length of the tube down) and the 90° axis (around the circumference of the tube), these layups add so-called hoop strength to the tube, making it less susceptible to crushing or bursting forces The effect of unidirectional prepreg on the 0° axis can mainly improve the longitudinal stiffness of the pipe.
Because the layup scheme has a direct impact on the specific properties of the pipe, it is necessary to adjust the performance of the finished carbon fiber pipe by changing the lamination of the carbon fiber prepreg, or alternating the direction of the unidirectional carbon fiber prepreg, so that it can be more meet application requirements well. For example, the tubing used for the drive shaft needs to handle torsional forces, so the carbon fiber unidirectional tape can be laid up with off-axis alignment to better handle these torsional forces in such a way as to ±45°.
Carbon fiber tubes made of wound prepreg are ideal for supporting equipment that requires high bending stiffness and lightweight applications, such as automated mechanical rollers, robotic arms, equipment telescopic poles, and drone components. In addition, these pipes can be made of high-modulus and ultra-high-modulus carbon fiber materials according to their needs, and some special outer fabrics can also be selected for cladding.
Pultruded Carbon Fiber Tube:
Pultrusion is to impregnate carbon fiber bundles in resin and pass them through a mold with a predetermined inner cavity profile. The space between the central axis and the mold will determine the wall thickness of the carbon fiber tube, and then make it quickly by microwave heating. It is a process of entering into a gelation state to achieve curing and molding.
Because this technology can realize automatic continuous forming, high processing efficiency and low labor cost, but can obtain products of good quality, extremely low internal porosity and precise dimensions, so pultruded carbon fiber tube is the current method for manufacturing continuous carbon fiber composite profiles. Compare cost-effective methods. This technology is particularly suitable for forming parts with a certain cross-sectional shape and requiring a very straight length in the length direction.
In theory, the manufacturing process for pultruded carbon fiber tubes can produce tubes of almost any length, and transportation of the finished tube is often the main constraint. But in fact, the application of pultruded carbon fiber tubes is also very limited. This process of forming through continuous drawing is limited to the manufacture of some specific profile products, such as round, square, I-shaped. Pipes etc. In pultrusion, although most of the carbon fiber will extend along the direction of the tube, which can create great stiffness, the carbon fiber tube produced by this process will show poor hoop strength or transverse strength, compared with coiled carbon fiber. The overall performance of the pipe is quite different.
