Q: What is a Double Belt Continuous Press?
A: A double belt press, as the name suggests, is a device that continuously applies heat and pressure to materials using two annular steel belts. Compared to batch-type platen presses, it allows for continuous production, improving production efficiency.
Q: What are the types of Double Belt Continuous Presses?
A: The current domestic and international double belt presses.: By function: Isochoric DBP (constant volume) and Isobaric DBP (constant pressure). By structure: Slider type, roller press type, chain conveyor type, and Isobaric type.
Q: What is an Isobaric Double Belt Press?
A: An Isobaric DBP uses fluid (either gas like compressed air or liquid such as thermal oil) as a pressure source. The fluid contacts the steel belts, and a sealing system prevents leakage. According to Pascal’s principle, in a sealed, interconnected container, the pressure is uniform at all points, leading to uniform pressure on the steel belts and materials. Hence, it’s called an Isobaric Double Belt Press.
Q: What is the current status of carbon paper in China?
A: Carbon paper, a key component in fuel cells, has been dominated by foreign companies such as Toray and SGL for many years. In recent years, domestic carbon paper manufacturers have made breakthroughs, with performance reaching or even surpassing foreign levels. For example, products like the Silk Series from SFCC and the roll-to-roll carbon paper from Hunan Jinbo(kfc carbon) have made significant progress. The performance and quality of domestic carbon paper are closely related to materials, processes, and other factors.
Q: In which process of carbon paper production is the Isobaric DBP used?
A: The production process of roll-to-roll carbon paper mainly involves continuous impregnation of the base paper, continuous curing, and carbonization. The curing of the resin is the process that requires the Isobaric DBP.
Q: Why and what are the advantages of using the Isobaric DBP in carbon paper curing?
A: The Isobaric Double Belt Press, with its consistent pressure and temperature, is particularly well-suited for hot-press curing of resin-reinforced composites. It performs effectively for both thermoplastic and thermosetting resins. In earlier roller-based curing processes, where the rollers only made line contact with raw materials, continuous pressure could not be maintained during resin heating and curing. As the resin’s fluidity changes and gases are released during the curing reaction, it becomes difficult to achieve consistent performance and thickness, which greatly affects the thickness uniformity and mechanical properties of the carbon paper.In comparison, isochoric (constant volume) double belt presses are limited by their pressure type and precision, which can be affected by thermal deformation. The isobaric type, however, fundamentally offers higher absolute pressure precision, making this advantage even more pronounced in the production of thin materials under 1mm. Therefore, from both a precision and a thorough curing perspective, the Isobaric Double Belt Press is the preferred choice for continuous roll-to-roll curing of carbon paper.
Q: How does the Isobaric DBP ensure thickness precision in carbon paper curing?
A: Due to the requirements for fuel cell assembly, thickness accuracy is a critical parameter for carbon paper. In the continuous production process of carbon paper, the main factors determining thickness accuracy include the thickness of the base paper, the uniform distribution of impregnated resin, and the uniformity and stability of both pressure and temperature during curing, with pressure stability being the most crucial factor. After resin impregnation, carbon paper generally becomes more porous in the thickness direction, so even slight pressure can cause deformation. Thus, the stability and consistency of pressure are essential to ensure accuracy after curing. Additionally, at the start of the curing process, as the resin is heated and gains fluidity, the rigidity of the steel belt combined with static fluid pressure helps to correct initial unevenness in resin impregnation, significantly improving thickness accuracy.
Q: Why does Mingke use compressed air as the static pressure fluid in the Isobaric DBP for carbon paper curing? What are the advantages and disadvantages?
A: The principles of static fluid pressure are consistent for both options, but each has its own advantages and disadvantages. Hot oil, for instance, poses a risk of leakage, which can cause contamination. During maintenance, the oil must be drained before the machine can be opened, and prolonged heating leads to degradation or loss of the oil, requiring costly replacement. Moreover, when hot oil is used in a circulation heating system, the resulting pressure is not static, which can affect pressure control. In contrast, Mingke uses compressed air as the pressure source. Through years of iterative control technology development, Mingke has achieved a precision control of up to 0.01 bar, providing extremely high accuracy ideal for carbon paper with stringent thickness requirements. Additionally, continuous hot-pressing allows the material to achieve superior mechanical performance.
Q: What is the process flow for curing carbon paper with an Isobaric DBP?
A: The process typically includes:
Q: What are the domestic and international Isobaric DBP equipment suppliers?
A: International suppliers: HELD and HYMMEN were the first to invent the Isobaric DBP in the 1970s. In recent years, companies like IPCO (formerly Sandvik) and Berndorf have also begun to sell these machines. Domestic suppliers: Nanjing Mingke Process Systems Co., Ltd. (the first domestic supplier and producer of Isobaric DBPs) is the leading supplier. Several other companies have started to develop this technology as well.
Q: Briefly describe the development process of Mingke’s Isobaric DBP.
A: In 2015, Mingke’s founder, Mr. Lin Guodong, recognized the gap in the domestic market for Isobaric Double Belt Presses. At that time, Mingke’s business was focused on steel belts, and this equipment played a key role in the development of domestic composite materials. Driven by a sense of responsibility as a private enterprise, Mr. Lin assembled a team to begin the development of this equipment. After nearly a decade of research and iteration, Mingke now has two test machines and has provided testing and pilot production for nearly 100 domestic composite material companies. They have successfully delivered around 10 DBP machines, which are used in industries such as automotive lightweighting, melamine laminates, and hydrogen fuel cell carbon paper production. Mingke remains committed to its mission and aims to lead the development of Isobaric Double Belt Press technology in China.
Post time: Nov-07-2024