Panoramic Analysis Of Composite Winding Process – The Past and Future Of Technology

 

 

Overview Of Fiber Winding Process

 

The winding molding process is to wind the continuous fiber (or cloth tape, prepreg yarn) soaked in resin glue onto the core mold according to a certain rule, and then solidify and demold to obtain the product. According to the different physical and chemical states of the resin matrix during fiber winding molding, it is divided into three types: dry winding, wet winding and semi-dry winding.

 

Dry winding is to use prepreg yarn or tape treated with pre-impregnation, and heat it on the winding machine to soften it to a viscous flow state and then wind it onto the core mold. Since the prepreg yarn (or tape) is professionally produced, the resin content (accurate to within 2%) and the quality of the prepreg yarn can be strictly controlled.

 

Therefore, dry winding can accurately control the product quality. The biggest feature of the dry winding process is high production efficiency, winding speed can reach 100-200m/min, winding machine is clean, labor hygiene conditions are good, and product quality is high. Its disadvantage is that the winding equipment is expensive, and it is necessary to increase the prepreg yarn manufacturing equipment, so the investment is large. In addition, the interlayer shear strength of dry winding products is low.

 

Wet winding is to directly wind the fiber bundle (yarn-like tape) onto the core mold under tension control after impregnation.

 

The Advantages of Wet Winding are:

 

① The cost is 40% lower than that of dry winding;

 

② The product has good air tightness because the winding tension causes the excess resin glue to squeeze out the bubbles and fill the gaps;

 

③ The fiber arrangement has good parallelism;

 

④ During wet winding, the resin glue on the fiber can reduce fiber wear;

 

⑤ High production efficiency (up to 200m/min).

 

The Disadvantages of Wet Winding are:

 

① Large resin waste and poor operating environment;

 

② The glue content and finished product quality are difficult to control;

 

③ There are fewer types of resins available for wet winding.

 

Semi-dry winding is to add a set of drying equipment after the fiber is impregnated and on the way to the core mold to remove the solvent in the impregnated yarn. Compared with the dry method, the pre-impregnation process and equipment are omitted; compared with the wet method, the bubble content in the product can be reduced.

 

Among the three winding methods, wet winding is the most commonly used; dry winding is only used in high-performance, high-precision cutting-edge technology fields.

 

Current Development Status of Fiber Winding Process

 

The winding pipe process is an excellent process in the reinforced resin molding process that achieves full automation, high productivity, high raw material utilization, and low product cost. Therefore, it has broad development prospects. This chapter describes the progress and equipment of the pultrusion process winding pipe process in recent decades.

 

From the perspective of domestic development, in 1946, the first patent for fiber winding technology was registered in the United States, and the fiber winding molding process began to develop. According to the main motion mode of realizing the formation of the spiral line, the layout type of the winding machine used was basically completed in the 1960s, as shown in the figure below.

 

 

Figure Spiral Winding

 

In 1965, Beijing 251 Factory designed my country’s first horizontal fiber winding machine “525”, which was “retired” in 2011. In 1966, a toothed chain-type horizontal fiber winding machine with stepless adjustment of winding rules was designed. This machine does not need a hanging wheel, and can easily adjust the winding rules and yarn density, and produces gas cylinders of various specifications. Considering the structural layout, the chain winding machine used to produce gas cylinders of 15 L and below adopts a chain drive vertical plane layout; the chain winding machine used to produce gas cylinders of 20 L and above adopts a chain drive horizontal plane layout, and its sprockets are changed from two to four.

 

 

 

Figure Basic Horizontal Filament Winding Machine

 

 

Figure Horizontal Chain Fiber Winding Machine Transmission System With Stepless Winding Regulation (Beijing 251 Factory)

 

Figure “525” My Country’s First Horizontal Chain Fiber Winding Machine (Beijing 251 Factory)

 

In 1966, the Ministry of Textile Industry issued a large vertical fiber winding machine project, and five units participated, including the 43rd Institute of the Seventh Ministry of Machinery, China Textile Science Research Institute, Beijing 251 Factory, Taiyuan Heavy Machinery Factory, and Shaanxi Heavy Machinery Factory. The project was completed the following year and is still in use. In 1984, Beijing Electric Power Equipment Factory introduced a Canadian vertical winding machine.

 

Figure Vertical Arm-Wound Fiber Winding Machine

 

In 1974, Beijing 251 Factory successfully developed the X2 planetary fiber winding machine, which adopted the three-axis concentric planetary principle in the transmission system.

 

Figure Planetary Fiber Winding Machine (Beijing 251 Factory)

 

Since the 1990s, some universities and enterprises in China have carried out the research and development of MCFW and robot winding machines, such as Harbin FRP Research Institute, Wuhan University of Technology, Harbin Institute of Technology, China Shipbuilding 625 Institute, Wuhan Jiudi Composite Materials Company, Harbin University of Technology, Nanjing University of Aeronautics and Astronautics and its cooperation with Shanghai Wange Company, Suzhou Zhongke Times Electronic Technology Company, Hengshui Huacheng Company, Lianyungang Zhongtong Company, Lianyungang Weide Company, Shijiazhuang Lai De Company, Hunan Jiangnan Siling CNC Machinery Co., Ltd., Taiwan Provincial Industrial Research Institute, Taiwan Provincial Jincaixing Company, etc.

 

In 2000, the author visited the Industrial Research Institute in Hsinchu and learned that it had successfully developed a 7-axis winding machine. A few years ago, my country’s customs had clearly ordered that my country’s winding machines with more than four axes were restricted from export. Looking back on the past, the author is very proud of my country’s progress!

 

Figure Microcomputer-controlled 7-axis 4-linkage double-car heavy-duty winding machine (Wuhan University of Technology)

 

The microcomputer-controlled fiber winding tension yarn frame has been promoted at home and abroad. It was successfully developed by Suzhou Zhongke Times in the early 21st century and was first put into use by Beijing 251 Factory (2004). Wuhan University of Technology, Harbin Institute of Technology, Jiangnan Siling CNC and other units have also put it into use.

 

Figure: The Microcomputer-Controlled Yarn Winding Tension Creel and Winding Machine Developed by Suzhou Zhongke Times Company

 

In 2014, Shanghai Wanger Composite Materials Technology Company combined the technologies of five German companies and three domestic companies to successfully develop a robot-based fiber winding cylinder automatic production line, which has been exported to Japan. Taiwan Province purchased its 10-station winding equipment, and the liquefied gas cylinders produced have been certified by Germany.

 

Figure Domestic Fiber-Wound Gas Cylinder Automatic Production Line (Shanghai Wange Company)

 

In 2010, Shanghai introduced the continuous pipe production line of Italy’s VEM company and put it into production. In 2016, Xinjiang Yongchang Company introduced the continuous pipe production line of the British Tech-no⁃bll company. In recent years, Lianyungang and Chongqing have launched production lines with the same principle. Qingdao has developed a camless steel belt continuous pipe machine.

 

The lessons learned from domestic equipment development are that we must pay attention to the process and its software, the equipment must operate stably, and avoid steel belt slippage and overlap. Quanzhou Fujian Lutong Pipe Technology Co., Ltd. introduced European technology to manufacture a cam steel belt continuous pipe production line with a maximum production diameter of 4 m.

 

Heng’antai Company in Jingxian County, Hebei Province uses the American Fiberspar continuous pipe production process. Its 12th Five-Year Plan 863 Science and Technology Project-Research on Key Technologies for Flexible Submarine Pipes passed the expert acceptance organized by the Ministry of Science and Technology in 2016. Its continuous pipe production line.

 

Figure Continuous pipe production line of Hengantai Company in Jing County, Hebei Province

 

In 2020, Chongqing Qingyang Holding (Group) Co., Ltd./Henan Province Qinyang Composite Materials Research Institute and Puyang County Furuipu Building Materials Company successfully developed a high-efficiency continuous winding fiberglass pipe production line with a diameter of 10 mm~250 mm. This line has no steel belt modeling. On simple equipment, it can complete the continuous molding of fiberglass pipes at low cost and high efficiency, and its production speed can reach 2 m/min. The trick is that the traction crawler machine revolves and rotates synchronously. South Korea also has similar equipment. The small-diameter non-steel belt continuous winding fiberglass pipe production line and its traction components are shown in the figure.

 

Figure Small Diameter Non-Steel Strip Continuous Winding FRP Pipe Production Line

 

From the development situation abroad, FW) has developed very fast. Well-known manufacturers include Anderson Company of the United States, Goldsworthy Engineering, Entec-Engineering Technology, BSD Company of Germany, Waltritisch & Wachter Company, etc. The winding machine in the international market now has six axes.

 

Figure Anderson Microcomputer Controlled 6-axis Fiber Winding Machine in the United States

 

Founded in 2004, French company MFTech was the first to research and commercialize robotic winding. The robotic winding equipment provided by the company fully utilizes the flexibility of the robot and can be wound by grabbing the mold or driving the wire guide.

 

Figure MFTech Robotic Winding

 

Fiberspar, an American company, began commercial production of continuous winding flexible pipes in 1999 and is said to be the global industry leader today. Its production process is: extrusion of high-density polyethylene or cross-linked polyethylene thermoplastic plastic lining layer (pressure leakage prevention layer) – multiple circumferential winding of glass fiber epoxy layer (structural layer) – external coating of thermoplastic plastic layer (wear-resistant layer).

 

The entire production line is fully automatically controlled and consists of 14 winding machines, traction machines, curing furnaces, winding devices and two extruders. After fiber winding FRP on the plastic pipe, the outer plastic protective layer is extruded online to make the pipeline. The production speed depends on the pipe diameter, generally 2.7 m/min ~ 3.6 m/min. The continuous production length of a pipeline can reach 10,800 m, and theoretically it can reach unlimited length.

 

Figure Fiberspar continuous pipe production line in the United States

 

Application Areas of Fiber Winding Process

 

Application in Energy, Chemical Industry and Transportation

 

The main applications of winding products in the civil field include: composite pressure pipes, storage tanks, pressure vessels, breathing cylinders and natural gas cylinders, fan blades, towers, electric poles, insulators, sports and leisure products, industrial transmission shafts, various rollers, etc.

 

Figure Pressure Vessels, Gas Cylinders, Membrane Shells

 

As a modern industry, automobiles are developing rapidly under the impetus of science and technology. With the continuous improvement of the application level of automobile composite materials, the use of composite materials per vehicle will gradually increase. In 2015, the total amount of plastics and composite materials required by my country’s automobile industry was about 1.65 million tons. With the continuous development of molding technology and equipment, the application of composite automotive parts in the automotive field will expand day by day. In order to improve the lightweight and high-strength performance of automobiles, composite materials are gradually replacing traditional automotive manufacturing application materials. The main applications of winding technology in automobile manufacturing are drive shafts, exhaust pipes, turbocharger pipes, vehicle-mounted gas cylinders, energy absorbers, bumpers, etc.

 

The most demanded composite material in the marine ship field is composite pipes. The composite pipes formed by winding are widely used in offshore oil and gas transportation, offshore platforms and ships due to their corrosion resistance, oil resistance, high temperature resistance and other characteristics. In addition, there are also dredging pipelines, submarine oil hoses, submarine pressure hulls, deep-sea detectors, diving breathing cylinders, ship masts and other applications.

 

Figure Offshore Pipelines and Cables

 

Applications in the field of oil and gas engineering can be divided into onshore and offshore applications, mainly oil and gas transportation pipelines and dredging pipelines. Composite pipes are gradually replacing traditional steel pipes due to their superior corrosion resistance and are widely used in actual engineering.

 

Figure Terrestrial Oil and Gas Pipelines, Offshore Oil and Gas Pipelines

 

Application in Aerospace and Military Fields

 

The automated forming process of aircraft composite components mainly includes three types: fiber winding, fiber tape winding and fiber laying. Due to the high strength, high temperature resistance and corrosion resistance of winding products, winding products can be used in the aviation field to form parts such as radomes, engine casings, fuel tanks, aircraft auxiliary fuel tanks and filters. They can also be used in the forming of small aircraft and helicopter fuselages, wings, blades, landing gear and other structures. Many high-pressure gas cylinders on modern large jet airliners are manufactured using composite winding forming technology.

 

In the field of aerospace, winding forming technology is mainly used in the manufacture of Shenzhou spacecraft load-bearing components, satellite structures, return capsules, space systems, composite pressure vessels, solid rocket engine shells, etc. In the field of national defense and military industry, winding forming technology is mainly used in large missile composite launch tubes, torpedo tubes, attitude control systems, gun racks, rocket launch tubes, rail gun barrels, etc.

 

The winding and laying molding of advanced composite materials are key manufacturing technologies for core components such as solid rocket engine casings, large aircraft fuselages, wings, and wind turbine blades, and play a vital role in the implementation of major projects in my country and the development of the aerospace industry. For many years, my country’s composite winding and laying molding manufacturing technology has been facing the problem of “stuck neck”. On April 2, 2022, the multi-axis linkage composite CNC winding equipment, a national key project developed by Xinghuo Machine Tool Group Corporation and Wuhan University of Technology, was officially delivered to the client. As a result, the “stuck neck” problem of long-term reliance on foreign composite winding equipment has been completely solved, and Xinghuo Machine Tool Group Corporation has also fully achieved a major breakthrough in the independent control of key core technologies.

 

As an advanced material, composite materials have a very broad development space. Advanced composite materials have a series of advantages such as light weight, high specific strength, high temperature resistance and corrosion resistance. They are widely used in aerospace, national defense equipment and energy development, and have promoted the rapid development of related industrial fields. The wide application of composite materials depends to a large extent on the molding process of composite materials. Among them, winding and laying technology is a fast-growing and effective technology in recent years.

 

Winding technology refers to the method of continuously winding pre-impregnated rubber fibers or cloth tapes on a core mold or lining corresponding to the inner cavity size of the product under the conditions of controlled tension and predetermined linear shape, and then solidifying it into a product of a certain shape at room temperature or under heating conditions.

 

With the development of computer technology, information technology, and control technology, the functions of tape winding molding technology are constantly expanding. From a foreign perspective, the United States has applied the tape winding molding process to model development: 13 parts in the nozzle components of the MD-2 solid rocket engine and the engine nozzle of the “Dwarf” missile are all wound; Europe and Japan also widely use the tape winding molding process in the fields of spacecraft and weapons development: the booster nozzle of the European “Ariane” rocket, the shell of the French M51 missile, and the booster nozzle of the Japanese M-3S2, H-I, and H-H rockets are all using wound composite materials.

 

Figure M51 Missile Shell in Winding Molding

 

In China, my country has been developing composite winding equipment and its molding process since the 1960s. For example, Beijing FRP Research and Design Institute, 703 Institute of the First Academy of Aerospace, 43 Institute of the Fourth Academy of Aerospace, Harbin Institute of Technology and Huazhong University of Science and Technology have successively developed different composite winding molding equipment.

 

The multifunctional cloth tape CNC winding machine independently developed by Northwestern Polytechnical University has high working efficiency, and the wound products meet the model process requirements, becoming a key supporting equipment that can meet the development of high-performance engine nozzles and aerospace vehicle insulation and ablation-resistant parts.

 

However, the above-mentioned winding molding equipment is basically developed for rotating body parts with regular surfaces, and winding molding cannot be achieved for large irregular and complex structural parts such as wings, fuselages, and wind turbine blades of large aircraft.

 

With the development of composite material related technologies, tape winding and laying molding technology presents a development trend of multi-process composite, precision molding equipment, increasing application of CAD/CAM technology, combination of molding equipment and robots, increasing number of thermoplastic resin-based composite materials and continuous application of new curing technologies.

 

After more than 40 years of research and development, the research and application of composite winding and lay-up molding manufacturing technology in my country has taken shape, but it still faces a strict blockade of foreign technology and a serious shortage of technology reserves. The multi-axis linkage composite CNC winding equipment developed by Xinghuo Machine Tool Group and Wuhan University of Technology was officially delivered to the client. As a result, the long-term reliance on foreign composite winding equipment has been completely solved.

 

Figure Multi-axis Linkage Composite Material CNC Winding Equipment

 

The equipment delivered to the user this time is a key equipment of the national key project. It is an intelligent high-tech product integrating new processes, new material manufacturing technology, automatic control technology, etc. It can complete the winding processing and production of various non-metallic glass fiber and carbon fiber composite products in cylindrical, spherical, conical and other shapes. The equipment mainly has the characteristics of high degree of automation, high precision, and strong reliability. It has broken through many domestic technical bottlenecks, solved the domestic (technical) bottleneck problem, and filled the domestic gap.

 

Future Development Direction of Winding Process

 

Bio-based “Replacing Plastic with Bamboo”

 

Bamboo winding composite materials, with water-soluble amino resin as adhesive, are new bio-based materials processed and formed by winding process. They belong to new bio-based materials. Bamboo winding technology has broken the inherent understanding of human beings on the application of bamboo for thousands of years and opened a new journey of transformation of the traditional bamboo industry. Bamboo winding composite material technology can be widely used in municipal, water conservancy, construction, transportation, petrochemical, marine, aerospace, national defense construction and other fields, and plays an important role in the development of the national economy.

 

Figure Bamboo Winding Products Developed by the International Bamboo and Rattan Center and Zhejiang Xinzhou Bamboo-based Composite Materials Technology Co., Ltd.

 

High-Precision Multi-Axis Fiber Winding

 

The high-precision multi-axis fiber winding production line is a production line for producing high-precision, high-strength and other high-performance fiber winding products. It is mainly composed of winding machine tracks or gantry, drive bed head, bed foot, winding trolley, dipping system, wire guide nozzle flip device, arm feeding device and yarn rack, electronic pneumatic servo tension control system, heating device, PLC control system and electrical control system and safety protection system. It can meet the production of axisymmetric structural parts such as spheres, cones, cylinders, (semi) ellipsoids, rectangles and combinations of various resins and fiber systems. It is suitable for transportation and aerospace fields with high requirements for product performance.

 

Figure Multi-axis Fiber Winding Machine COMET

 

Continuous Winding of Carbon Fiber

 

Carbon fiber, due to its excellent performance, has gradually become the mainstream material for hydrogen cylinder manufacturing. However, in the early days in China, due to the immature preparation technology of 70 MPa carbon fiber wound IV type bottles and the difficulty of large-scale production, the preparation cost was relatively high, which limited the widespread application of this technology. But with the continuous development of technology and the expansion of production scale, the cost has gradually decreased, which has laid the foundation for the further popularization and application of hydrogen cylinders.

 

In the technological evolution of hydrogen cylinders, type III and type IV cylinders mark an important transition. These two types of cylinders are mainly composed of liner and fiber winding layer, using advanced composite material technology. The liner is usually made of metal or other materials, while the outer shell is wound with high-strength fiber composite materials such as carbon fiber and glass fiber, which significantly improves the pressure bearing capacity and safety of the cylinder.

 

Figure IV 700bar High Pressure Hydrogen Storage Tank – Carbon4 Tank