Surface Plain Carbon Fiber Square Tube

Carbon fiber square tubes, also known as carbon fiber square profiles or carbon fiber box sections, are hollow structures with a square cross-section made from carbon fiber reinforced polymer (CFRP) composites.Are manufactured using state-of-the-art techniques, including pultrusion as well as compression molding technique to ensure high quality and durability. In the pultrusion process of fabrication of carbon fiber tubing the continuous pulling of carbon fiber composites is mixed with resin matrix through heated forming dies to create continuous length of tubes which provides tubes with unidirectional properties.

Cartbon fiber is a very common type of carbon fiber tube. Square tubes have better dimensional stability and are mostly used as supports, fork arms and robotic arms. Because Future has worked in the catbon fiber product industry for more thantenyears,we have produced many sizes of carbon fiber square tubes. The production of carbon fiber square tubes is usually by means of a molding process. The entire compression molding is mai nly the fllow ing steps:

Molding
First, the veallesign is camied out according to the size drawings of the cartbon fiber square tube. After the detaill are cofrmed, the square tube mold and a series of mold supporting components will be designed to ensure that the formed carbon fiber square tube can be sccessfully demolded. If the size of the square tube is relatively large, it is also necessary to determine the thickness to ensure that the overal flatnes of the produced carbon fiber square tube is better.

Prepreg cutting
Acording to the size of the square tube, the carbon fiber prepreg is cut, and the appropriate layup design is carried out, such as 0*, 90* superposition, etc. In the design of the layup, the actual stress situation of the square tube shouldbe comb ined to carry out the layup of the layup. In the layup, tryto avoid the existence of alir bubbles, so that the intemal flatness of the carbon fiber tube will be better.

Paving and mold clamping
After the moldis made and the prepreg is cut, the material is spread. After laminating the entire carbon fiber square tube blank, put it into the mold and dlose the mold, and then make the whole structure more compact and stable. and the owerall product accuracy of the carbon fiber square tube will be higher. In the process of mold loading, the mold can be properly preheated, including ppying mold release agent in the mold, which can better ensure the product perfomance of the carbon fiber squaretube.

Product curing and molding
After the product is molded, it is put into a hot press together with the mold for heating and pressurization. Since the heat press is an open equipment, speciall attention should be paid to the temperature and time parameters of the molding. The high-quality carbon fiber square tubeis determined by temperature, pressure and time. After the molding. it needs to maintain pressure and heat preservation.

Product release machine processing
After the entire mold has cooled, take it out from the heat press, and then open the mold to take out the carbon fiber square tube. After demoulding, the carbon fiber square tube needs to be further processed, and fnlly the finished product that meets the use standard canbe obtained.

The primary raw materials used in the production of carbon fiber tubes are carbon fibers and a polymer matrix, usually epoxy resin. Carbon fibers are derived from precursor materials such as polyacrylonitrile (PAN) or pitch. PAN-based fibers are more common because of the high strengths and modulus properties they possess. The PAN conversion process into carbon fiber ensues in the following steps: stabilization, carbonization, and graphitization, where the precursor is heated to temperatures as high as 3,000°C in an inert atmosphere to remove non-carbon elements and align the carbon atoms into a crystalline structure. This process results in fibers with tensile strengths up to 5.5 GPa and a modulus of elasticity of ~230 GPa.

Pitch-based fibers, on the other hand, are derived from petroleum or coal tar pitch and can produce fibers with ultra-high modulus values, making them suitable for applications requiring extreme stiffness. The pitch is first mesophase-pitched and then carbonized similarly to PAN fibers. Although these fibers can achieve a modulus exceeding 900 GPa, their tensile strength is generally lower compared to PAN-based fibers. Pitch-based fibers also exhibit a higher thermal conductivity, making them ideal for heat-dissipating applications, with values reaching up to 600 W/m·K.

The epoxy resin acts as a binding agent, providing rigidity and durability to the final composite structure. Epoxy resins are chosen for their excellent adhesion properties, chemical resistance, and mechanical strength. The polymer matrix not only holds the carbon fibers together but also transfers loads between fibers, helping to maintain the structural integrity of the composite. The curing process of the epoxy resin involves a chemical reaction between the resin and a hardener, typically amines or anhydrides, which cross-links the polymer chains to form a rigid, three-dimensional network. The glass transition temperature (Tg) of cured epoxy resins typically ranges from 120°C to 180°C, depending on the specific formulation.

Ther materials like hardeners and additives may be used to enhance specific properties of the carbon fiber tubes. Hardeners are crucial for initiating the curing process, and their selection can affect the thermal and mechanical properties of the final product. Additives such as UV stabilizers, flame retardants, and impact modifiers can be incorporated to improve the durability, safety, and performance of the carbon fiber tubes in various environmental conditions. For instance, incorporating nanoscale fillers like carbon nanotubes or graphene can significantly enhance the mechanical properties and electrical conductivity of the composite. Carbon nanotube-reinforced composites can exhibit tensile strengths up to 6 GPa and electrical conductivities in the range of 10^2 to 10^3 S/m.