Analyze the quick response of Japanese molds trying to surpass Chinese molds

by:Gewinn     2022-04-22
Japan's mold industry is in trouble due to the hollowing out of the domestic industry, the rise of China's mold industry, and the impact of the economic downturn caused by the Lehman incident. In this context, the number of mold manufacturers in Japan decreased from more than 8,000 in 2000 to more than 5,000 in 2008, and the output of molds also fell by half, from about 1 million sets in 2002 to more than 500,000 sets in 2009. . In such an environment, Japanese mold and machine tool makers are also attracting attention as they strive to get out of the predicament and create new charms for their customers. According to Luo Baihui, head of the International Mould and Hardware and Plastic Industry Suppliers Association, in recent years, Chinese mould enterprises have enjoyed a good reputation in the world for their efficient and low-cost operations. Not only is the price cheap and the delivery time short, but also China's mould technology level is also very high. By leaps and bounds. Japanese companies try to surpass Chinese companies in three aspects: ① ultra-precision, ② long life, and ③ high speed to put products on the market faster, so as not to lose the opportunity to sell products. Find a Chinese mold manufacturer that is reliable in technology and capital, and make full use of its low price advantage to reduce your own costs. This practice will be extended to Japanese companies in the future. In order to shorten the processing time before the mold is completed, Japan's Matsuno Mold Manufacturing Co., Ltd. uses a 5-axis synchronous control machining center (MC) to complete the mold faster than before, shortening the lead time before supplying to customers. Matsuno Mold (Headquarters: Higashi-Osaka City, Osaka Prefecture) produced molds for molding resin car audio panels in half the time. Compared with the general-purpose MC controlled by 3 axes, the 5-axis synchronous control MC has an increased degree of freedom of die cutting (tilting), and can more flexibly set the attitude of tools such as ball end mills to the die. In this way, the tool can reach the part of the deep shape for machining the cavity that cannot be cut by the general-purpose MC, so it can be formed by direct cutting. However, if the original electric discharge machining is used, it cannot be formed. The reason why the company uses the 5-axis synchronous control MC to machine the mold is to reduce the electric discharge machining, which is more time-consuming than cutting. Conventionally, when manufacturing molds for molding car audio panels, one general-purpose MC was used to cut graphite and copper electrodes required for electrical discharge machining, and another general-purpose MC was used to roughen the mold. The rough-machined mold is then subjected to electrical discharge machining using the electrode made by cutting. In this way, not only the electrode cutting time is much longer than the rough machining of the mold, but also the electric discharge machining takes a long time. In addition, electrical discharge machining will also form a hardened layer on the surface of the mold, which needs to be polished in a post-process. In order to shorten the processing time, Matsuno Mould uses 5-axis synchronous control MC to process the mould by cutting as much as possible. By this means, the shape of the electrode is simplified and the ratio of electrical discharge machining is reduced. As a result, the machining time of the new car audio mold, including the time for CAM data creation and machining preparation, was only about 150 hours in total. It used to take about 300 hours. Moreover, the shortening of the processing time can also reduce the processing cost of the mold, 'a mold is expected to be reduced by about 30%'. The future goal of Matsuno Mould is 'Electric Discharge Machining'. If EDM can be completely eliminated, at least electrodes can be eliminated. Machine tool costs can also be reduced by being able to replace three machine tools (two general-purpose MCs and one EDM) with one 5-axis synchronous MC. Moreover, the electrode inspection work required by the customer can also be omitted. In addition, since the number of times the workpiece is fixed on the machine tool (the number of times of machining preparation) is only required once, the mold can be completed with high precision. But there are also problems. When using 5-axis control MC to prepare complex CAM data, the mold for car audio 'requires 80 hours by one operator'. And the types of knives will also increase. But nonetheless, this approach is still effective in increasing the speed before delivery. Okuma has developed the door type MC-MCR-H (Hyper)' for the purpose of shortening the delivery time, and prototyped the mold for the outer side panel of the automobile. By cutting the mold at high speed and high precision, the labor of manual grinding work is reduced. The burden. As a result, the finishing time of the mold was shortened to 60% of the original. Okuma obtained the actual vehicle data of the 2L displacement class from the Japanese car manufacturer, and made the mold based on the data. Although the car manufacturer will not use it in mass production This mold, but Okuma still prototyped the actual mold. The MC used for cutting uses linear motors on the X-axis and Y-axis to increase the maximum cutting feed rate to 30m/min. In addition, it is equipped with a predictive tool that minimizes heat generation The Thermo-Friendly Concept function that corrects the influence of residual heat. In this way, even though the mold is cut at high speed, the mold surface still achieves excellent machining accuracy. The material of the mold is gray cast iron FC250, and the size is 3345 × 805 ×1290mm. Using a ball nose end mill with a diameter of 30mm, the rotation speed is 30,000 rpm, the cutting feed rate is 21m/min, the cutting amount is 0.35mm, and the cycle feed rate (PickFeed, the path distance between the centers of adjacent tools) ) was 0.35mm, and the mold surface was machined. After that, light manual grinding was performed. With the above measures, Okuma shortened the processing time including MC cutting and manual grinding to 28 hours and 52 minutes. The current machining method of cutting with MC using a ball screw and then carefully grinding it by hand takes about 45 hours. This reduces the total machining time of the mold to 128 hours and 5 minutes.
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