Processing quality and processing effects cannot be replaced

Beijing Nankou Rail Transportation Machinery Co., Ltd. (hereinafter referred to as “Nanji Company”) is located at the foot of Yanshan. This company was founded in 1906 by the famous railway engineer Mr. Zhan Tianyou. Nowadays it is China North Vehicle Machinery Transmission Integrated System. Three specialized R&D and production bases for railway turnout integrated systems and compressed wind source integrated systems, including gear factories, wind power plants, parts factories and foundries, which are responsible for the production of motorcycle mainframes and accessories. Assembly. Among them, the largest scale of the gear factory, regardless of the size, number of people or output value, the top staff of nearly 300 people create an annual output value of about 150 million yuan, accounting for one-third of the company's overall output value. the above.

Mr. Tan Jianzhong, deputy director of Beijing Nankou Rail Transportation Machinery Co., Ltd. Gear Factory

The gear factory has a wide variety of products. In addition to providing matching gear products for locomotives, it also undertakes the processing of some wind power and oil field speed increasing boxes, but its fist products are also the manufacture of locomotive traction gears. The locomotive traction gear is a large-speed high-speed heavy-duty gear. It is an important part in electric locomotives, electric drive diesel locomotives and high-speed electric traction drives. It transmits the torque generated by the traction motor and withstands the impact from the line, negative and working conditions. bad. As the railway develops to high speed and heavy load, its load is increasing, and the "service" conditions are becoming more and more demanding. In order to meet this development demand, the improvement of gear quality and service life is imperative. In this process, processing equipment and processing technology play a decisive role.

High-end matching under high-end demand

The core product of Nanji Company Gear Factory--HXD2 high-power electric locomotive traction gear is mainly produced for Harmony No.2. HXD2 "Harmony" electric locomotive is the main electric locomotive model of China Railway. It was jointly developed by Alstom Transport Co., Ltd. of France and Datong Electric Locomotive Co., Ltd. of China CNR Group. It is the "Prima" locomotive technology platform in Alstom. On the top of the French National Railways BB 27000 electric locomotive as the prototype, the development of the trunk freight, eight-axis high-power AC drive electric locomotive, the maximum power is 10,000 kW, the maximum operating speed is 120 km / h.

HXD2 high power electric locomotive traction gear

According to the requirements of cooperation, the supporting companies of CNR started to formally produce in 2007. For the description of the difficulty in manufacturing the traction gear of HXD2 high-power electric locomotive, Tan Jianzhong, deputy director of the gear factory, said: “The requirements for this gear product are high. Standard, it has the characteristics of high production precision, difficult processing, many inspection items, and complicated production process. At that time, our processing environment was not satisfactory, not only the processing accuracy problems, but also the difficult processing challenges. ."

Various gear products placed in the gear factory workshop

Harmony No. 2 belongs to the low-speed heavy-duty locomotive. The gear design is complex in shape. Many curves cannot be completed by ordinary equipment. “So we introduced a number of imported CNC vertical lathes. But the problem has also arisen. The tools equipped with these vertical vehicles are also available. Incomplete, and the tool is the key factor in determining the success or failure of the product. Walter not only recommends the most suitable tool for the processing difficulties, but also helps to adjust a lot of processing parameters, and complete the task while making the processing smoother. It can be said that We solved the urgent need," Tan said. Among the international tool makers he touched, Walter impressed him the most, especially the disc milling cutters, drills and taps that played the most important role.

So far, Nanji Gear Factory has become the main supplier of Harmony No. 2 gear accessory products, with an annual output of 2500~3000 pairs of main driven gears, and the products are also exported to France, becoming the gear of the French National Railway Alstom. Product B-level suppliers supply dozens of gears to them every month. At the same time, seven years later, the gear factory is still using Walter's products. "It is not that the tool's product function cannot be replaced by other manufacturers, but the processing quality and processing effect are irreplaceable by other tools."

Tool solves processing bottleneck

Although the cost of tooling accounts for only 5% of the total cost, it restricts the remaining 95% of the processing cost. As a product that is in direct contact with the workpiece, the machining level of the tool directly affects the quality and processing efficiency of the workpiece. Tan has a deep understanding of this point. According to his recollection, there was a deep hole on the HXD2 gear that needed to be machined. It was an elongated hole with a diameter of 5 mm and a depth of 186 mm. "We chose a lot of drill bits from many manufacturers, but they could not solve the problem because of the depth and The diameter ratio is too large, and the machining accuracy is not mentioned at the moment. This process could not be realized at that time, and there is no way to carry out the following work."

Applying Walter drills to machine deep holes

Moreover, the uniqueness of the position is only a problem in the process of processing the HXD2 gear in the gear factory. Another problem is the particularity of the gear material. For low-speed and heavy-duty transmission gears, the tooth surface is easily deformed by plastic deformation and wear, and the teeth are easy to break. Therefore, materials with good mechanical properties such as mechanical strength and hardness should be selected. The material of HXD2 gear is 18CrNiMo6. This material is characterized by relatively hard material and hard core of the gear, which can reach Brinell hardness (HB) of 370~450.

Walter's solution to this processing bottleneck quickly helped them solve the problem, and the product is still being used today. This high-efficiency drill bit model from Walter is B4015.F20.21, 0.Z02.105R, and the insert type P6001-D21.83R WXP45. The insert has a chisel edge design, and the drill tip and the outer side are ground. The blade is sharp. Positive inserts, similar to solid carbide belts, with new edge allowance for smaller hole tolerances and better surface quality, enabling high metal through brisk flexible cutting even on less powerful machines Removal rate.

Walter milling cutter has an overall competitive advantage

According to Tan’s director, there are more than 20 roads in the processing of gears. The main processes include roughing, aging, finishing, toothing, carburizing, quenching and grinding of rough parts. In the initial stage of cooperation with Walter, the use of its drill bit processing is often after quenching, because quenching will cause slight deformation of the workpiece. For holes with strict geometric tolerance requirements, it must be drilled after quenching. This is a great test for Walter's drill bit. Of course, with the improvement of the quenching process, Nanji Gear Factory gradually grasped the amount of quenching deformation, and further understood the role of this deep hole. "We found that some places where the position requirements are not high are allowed to expand the tolerance. "Therefore, Walter's drills are now used in the carburizing process, before the quenching process, so that the Walter drill bit can be used more efficiently to maximize the benefits."

Metal processing, the tool first. The processing examples of the Nanji Gear Factory fully demonstrate the importance of the tool in difficult machining. Especially for the processing of rigorous and difficult-to-machine materials, the role of high-efficiency tools is irreplaceable, and in these respects, the technology and product strength of Walter Tool Company is undoubted.

Nanji Company Gear Factory has strict evaluation standards for the selection of tools. In the words of Tan Director, it is shop around. "In fact, when purchasing tools, the price is not the main factor we consider. We mainly look at the tools. Service life and cutting effect. For tool products, we also have a trial period. During the trial period, we should count the tools used, such as the output of similar products per unit time.” The choice of Walter is also subject to such strict considerations.

After Walter helped the gear factory solve the processing bottleneck problem, the gear factory purchased some of Walter's turning and milling products. "This is because of our trust in Walter, not only because of its outstanding products. And because of their understanding of our processing, we can give the best solution for specific applications and find the right products for us.” Tan Director also affirmed Walter's technical service capabilities. It is for this kind of trust that the gear factory has purchased Walter's milling cutters and disc milling cutters. The single milling cutters are mainly used for the machining of gear tooth tips. The disc milling cutters are mainly used for the machining of large box-shaped workpieces. . “The disc milling cutter is mainly placed in the CNC gantry machining center for the plane milling of large valve bodies. This product is also where we think Walter has a strong competitive advantage compared to other similar tool products. Durable, and the machining accuracy and finish are both Very good, although the initial purchase price is more expensive, but the overall cost and long-term considerations are still worth the money.” Tan Director clearly pointed out that as long as the workshop has demand for drill bits and disc milling cutters, the first thing to think about It’s Walter.

Mr. Zhang Shiguang, Product Manager, Walter Greater China

“Over the years, Walter has been in close contact with the South Machine Company gear factory, not only in the use of the product, but also in the continuous optimization of the processing technology. Currently, Walter's latest blade products TNMG160408-MP3 WPP20S and WNMG100616-RP5 WPP30S is 'serving' in the workshop of the gear factory. The positive effect of our cooperation is far higher than the processing.” Mr. Zhang Shiguang, Walter Product Manager, said.

At present, Nanji Gear Factory has become the most stable and mature supplier of the largest power electric locomotive series supporting traction gear products in China due to its advanced technological means. “50% of the locomotive gears of CNR are processed and produced here, which means that almost every locomotive has our gear products.” Tan said with pride. “This kind of performance is absolutely inseparable from high-end. Equipment support, especially with the support of excellent tool suppliers like Walter."

Now, the gear factory is still working on gear matching products for the intercity type 1 high-speed train that will be released soon. The intercity type 1 runs at 250 km/h. “This project needs to be purely localized, given our outstanding performance. Performance, the gearbox on this line will be provided by Nanji Company.” Tan factory director said that the gear factory will soon undertake the processing task of the intercity type 5 (running speed of 300 km/h) high-speed motor car gear. . Because the driving method of the Harmony is different, the intercity high-speed train will use more gear products, and the accuracy and level requirements of the gears will be higher. Tan said: "As the processing requirements increase, In the future, we will also have some difficult machining needs to rely on the experience of high-end tool manufacturers. If there are deep holes with difficult materials or special processing positions, we will first think of Walter."