The commencement of the 500 km/h high-speed EMU project by CSR Zhuzhou Motor Co., Ltd. marks the establishment of China’s world-leading position in high-speed rail. Our company is deeply honored to have been selected as one of the primary manufacturers of insulation-molded components for the traction transformers in this project, while also recognizing the significant responsibility that comes with this role.

　　For this 500 km/h high-speed EMU, the insulation components of the traction transformer are made from a material that differs from previous applications: an aromatic polyamide product manufactured by DuPont, a world-leading U.S. company. In the past, T4 high-density cardboard was used, which has relatively high water absorption. Within a certain range, the tensile strength of T4 cardboard decreases as its moisture content increases, while its elongation at break increases with rising moisture content—this characteristic gives it excellent bend-forming properties. For the upper-end insulation components of the 500 km/h high-speed EMU’s traction transformer, NOMEX 994 fiber laminated board is employed. This material is a high-density rigid board with unique performance characteristics: even at elevated temperatures, it exhibits exceptionally strong compressive resistance and mechanical strength. However, precisely because of its outstanding rigidity, its inherent limitations become readily apparent during subsequent processing and fabrication, presenting unprecedented challenges to the entire production process and introducing considerable uncertainty as to whether the project can commence on schedule and proceed smoothly.

　　Initially, several companies were granted production licenses for this project and, drawing on their many years of extensive experience, actively engaged in manufacturing. However, during the entire production process, our company was the first to discover that NOMEX 994 fiber laminate material could not be formed and failed to meet CRRC Zhuzhou Motor’s technical requirements. Our technical department promptly relayed this information to CRRC Zhuzhou Motor’s technical team, after which several other manufacturers also reported difficulties in forming this material. In response, relevant leaders and experts from CRRC Zhuzhou Motor immediately convened an emergency meeting with our company and several other production suppliers to discuss how to address the challenges ahead. During the meeting, our technical personnel conducted a comprehensive analysis of the issue of end insulation being unable to be formed: DuPont’s NOMEX 994 fiber laminate is a high-density rigid board with a specific gravity of 1.1–1.2; it is composed of aromatic fibers, exhibits poor water absorption, has excellent temperature resistance and high hardness, but very limited plasticity. To assess the material’s processability, both CRRC Motor’s authoritative technical experts and our company separately consulted DuPont specialists in Shanghai, Shenzhen, and other locations, seeking detailed information on the forming technology for this product. The response was that, based on current market feedback in China and Europe—and indeed at DuPont’s global headquarters—there is still no mature experience in forming NOMEX 994; this remains a worldwide challenge. In light of these specific circumstances, our technical department proposed a response plan to tackle this global challenge: conventional processing methods would not work. We recommended that the motor manufacturer make the following adjustments to the original design and submit sample parts the next day for expert review by CRRC Motor. Specifically, the original design called for a 3 mm + 6 mm NOMEX 994 laminated structure, which was revised to a 3 mm + 3 mm + 3 mm configuration; furthermore, the original design specified two stacked layers, whereas the revised design calls for three layers bonded together as a single unit. Given the tight project schedule and the considerable technical difficulty, in order to ensure that qualified samples could be produced within the prescribed timeframe, company leadership personally visited the production site, working alongside the technical and production departments and relevant production staff to devise innovative solutions and break with conventional practices. Taking into account the inherent characteristics of NOMEX 994, we adopted a multi-stage forming approach: alternating internal and external molds for successive shaping stages, with stepwise temperature control during baking and appropriately extended curing times. This new process enabled the final product to largely comply with CRRC Zhuzhou Motor’s technical requirements, and the first sample was delivered on time and to the required quality standards.

　　On November 14, 2010, leaders and experts from the Technical Department of CSR Zhuzhou Motor Co., Ltd. convened in our company’s conference room to discuss matters related to the manufacturing technology for the end insulation of the traction transformer used in CSR’s 500 km/h high-speed EMU. They conducted an on-site evaluation of the end-insulation samples produced by our company. Following confirmation by CSR Motor’s Technical Department, the product samples were found to generally meet the required performance specifications; however, Zhuzhou Insulation Company was advised to further enhance its manufacturing processes. The review was subsequently approved. In addition, the experts and company leaders highly commended our production capabilities and overall manufacturing standards, noting that, within such a short timeframe, we had successfully addressed the global challenge posed by DuPont’s NOMEX 994 molding process and thereby established ourselves among the world’s leading companies. During the meeting, relevant leaders from CSR Motor announced on the spot that the production of the end insulation for the traction transformer of the 500 km/h high-speed EMU would be consolidated from the original three suppliers to a sole supply by Zhuzhou Insulation Company. Given that this is a new technology, Zhuzhou Insulation Company was requested to provide technical support throughout the manufacturing and production process at CSR Motor. As the saying goes, “You reap what you sow”—hard work ultimately pays off.

　　In our future work, we will steadfastly uphold the business philosophy of “focusing on long-term development and driving innovation through technology,” diligently learn and conduct in-depth research, and make our due contribution to building our company into a world-class, technology-driven enterprise.