Overview of the development of the Japanese machine tool manufacturing industry and the first Japan Machine Tool Fair Wu Liang Metallurgical Machinery Factory Li Liangfu held the 19th Japan Metal Cutting Machine Tool Expo (19JITOF) in Osaka City at the end of 1998, demonstrating the achievements of the Japanese machine tool manufacturing industry.
1 Development Characteristics of Japanese Machine Tool Manufacturing Japanese machine tool manufacturing companies have been mainly engaged in two directions in recent years. First, we strive for high speed and shortened auxiliary time, develop multi-functional machine tools, and increase the productivity of machine tools to achieve the most modern process. Second, the development of new models of machine tools, the use of the principle of cost minimization, the machine tool manufacturing process is more reasonable, the result is a significant reduction in sales prices.
In the case of a significant reduction in the demand for machine tools, most machine tool manufacturing companies have not reduced the cost of scientific research and experimental design work. Many companies that produce machine-like machines have stabilized certain companies that have the ability to stabilize demand on the international market, such as CNC systems and industrial robots.
2 Development of Japan's machine tool manufacturing industry During the period from 1996 to 1997, Japanese machine tool users began to increase investment in major metal processing equipment to replace a large number of CNC machine tools installed in the 1980s. In addition, Japanese immigrants living in other countries began to purchase Japanese-made machine tools, which led to continued growth in orders for 45 consecutive months. In 1997, the order volume increased sharply to 0.6 billion yen. At the same time, the share of CNC machine tools in production increased from 75.7 to 83.3, their export volume increased from 35 to 64.4, while the import volume increased from 7.5 to 15. In 1999, the order quantity of Japanese machine tools exceeded 1.4 trillion yen.
3 New production organization principles 3.1 The current production restructuring The market downturn requires Japanese machine tool manufacturers to take fundamental measures, including reducing the number of workers and reducing the size of transactions, by closing the production or sales of enterprises or companies, the purpose It is to reduce production costs and other expenses. For example, the number of permanent workers in the Japanese machine tool manufacturing industry has decreased from 37,952 in 1992 to 27,487 in 1997, a decrease of 28 points.
After World War II, the United States tried to infiltrate its marketing forms and methods into Japan. However, Japan has not blindly copied these methods, but based on the reference, established a marketing system that adapts to the characteristics of its national culture.
Under the pressure of the objective situation, Japan has transferred mass production to developing countries and regions, such as Brazil, South Korea, Taiwan, and Singapore. In this way, Asia and parts of South America have become industrial centers, where industrial products are produced and assembled according to the processes of industrialized countries (first Japan). The domestic production in Japan is relatively insignificant.
3.2 The traditional practice of developing economical products is that manufacturers focus on reducing production costs. To do this, you must simplify complex mechanisms and eliminate unnecessary functions in the series. At the same time, try to use standardized parts to reduce the variety of homemade parts and reduce the cost of the products.
The development of information technology and network technology can enable machine tool manufacturers to effectively control the production process and sales process, and decentralize resources according to different countries and regions to optimize the entire economic process, achieving the goal of minimum expenditure and maximum return.
Significant achievements have been made: a number of CNC machine tools are connected into a flexible manufacturing system to comprehensively control the production process to connect the computer into the information network to obtain materials and accessory information, and computer-aided design and manufacturing have emerged as a computer integrated automation factory.
3.3 Parallel design In Japan, the development of new machine tools is based on the principle of sales and production, and is designed specifically for the special requirements of the orderer.
The variety of products and the shorter delivery times have led to a new approach â€“ parallel design. It is the simultaneous design and manufacture of products based on computer-aided production. Nowadays, more and more Japanese machine tool manufacturers have used parallel design systems.
3.4 Quality Inspection, Safety and Environmental Protection Japanese companies involved in production automation are currently focusing more on compliance with the ISO9000 and E (European Safety Standards) series of standards. The number of Japanese companies that have obtained ISO9000 series certificates is increasing. This not only demonstrates the reliability of its products in European and international markets, but also motivates its employees to realize the importance of the company's product quality and safety.
In Japan, the number of companies that have obtained ISO14000 series (ecological) certificates is also increasing. A series of machines that work without coolant have been developed.
At the exhibition, special equipment was created to ensure ecological safety and comfort. For example, Akaatsu eletri FG showed a high cleanliness (up to 99.93) in the production of air for the production of the telescopic rods 2. Parallelograms 3. Spindles. In the automatic fire extinguishing system exhibited by Onikaze, an F-type plenum was installed.
4 19 Some exhibits on JITOF 4.1 Six-legged machine tool (virtual axis machine tool) In the past 10 years, a new concept machine tool has appeared in the world machine tool equipment market, commonly known as the six-legged machine tool (virtual axis machine tool), which is based on the telescopic rod structure and can guarantee The working organization (activity platform) has 6 degrees of freedom. Synchronous control of the telescopic rod allows the platform to be positioned in 6 degrees of freedom at the same time.
Hitachi Seiki Co., Ltd. exhibited a drilling center developed on this principle.
20000r/in. Spindle speed and axial movement can be controlled synchronously, so tapping with taps at n â‰¤ 10000r/in eliminates the need for special chucks.
The company also exhibited the Delta 1000 small high-speed six-legged robot (three or four coordinates to control the maximum snatch weight of 1kg moving parts moving speed of 270 / in), 150 cycles per minute.
Daxie exhibited a new vertical overspeed six-axis machining center, also based on the six-legged principle. The machining center can machine parts with bevels and angles of Â±30Â° with a maximum travel speed of 100/in and an acceleration of 1.5g. The main drive has a power of 7.5kW n up to 30000r/in. The machine features telescopic rods. A spherical support structure is used to ensure different angles of rotation.
Fanu exhibited the new Fanu F200i robot with a six-legged mechanical part. Six telescopic rods are mounted on the base with special support. On the upper platform to which the telescopic rod is attached, the working mechanism (spot welder) is arranged. The platform ensures that the welder moves in 6 coordinates, which is a part that can weld complex shapes. The robot is characterized by high rigidity, simple structure and compactness. No turning hands ensure the safety of the operator. The moving speed of the snatch weight mechanism is 24/in in the horizontal plane, 12/in in the vertical plane is Â±20Â° in the horizontal plane, and Â±10Â° in the vertical plane. The repeating positioning company exhibits high-speed horizontal machining. Center (with photos). Its layout differs from the traditional six-legged 6-bar layout. In order to move the sleeve spindle 3 in the horizontal plane, two telescopic rods 1 and 4 and a hinge parallelogram are used. 2. The latter will withstand cutting forces and can be improved. The stiffness of the entire structure. The machine control system is simpler than the traditional six-legged, because there is no need to coordinate the position of the platform that supports the six poles. The machine's characteristics are: automatic tool change time (from cutting to cutting)
0 .7s Maximum moving speed is 6 0 4.2 Dry cutting machine structure and machining process On the exhibited machine tools, a lot of problems related to dry cutting are mainly solved by the following methods: ensuring rapid dissipation of heat caused during cutting. Slots prevent hot chips from heating machine parts. For this reason, the basic layout of the machine tool layout that facilitates the removal of chips is thermally symmetrical, and the material with low thermal conductivity (such as artificial granite) is widely used in the machine configuration of the vertical configuration spindle.
In addition to having a good influence on the machining process, the machined surface condition and the tool durability, the coolant also has an important function, namely chip removal in the cutting zone. However, the amount of chips removed during high-speed cutting is many times greater than that of conventional cutting, so this function of the coolant is unrealistic in most cases. Therefore, the overspeed machine will be equipped with equipment for compressed air, vacuuming and sealing the work area. In most cases, dry cutting is possible as long as the quality of the part and its manufacturing time are not worse than when the coolant is used.
After solving the problems related to the structure of the machine tool for high-speed dry cutting, it is recommended to use a large amount of cutting.
In order to supply a limited amount of coolant, a new toolholder structure has been developed. For example, for an end mill holder with a diameter of only 2, if there is no hole in the cover that is screwed onto the collet body, the coolant enters the cutting zone through a dedicated hole in the end mill. If the cover has a pre-hole, the hole will function as a nozzle which determines the characteristics of the coolant jet and forms a water jacket around the end mill.
4.3 Improving the traditional structure of the machine tool To ensure the competitiveness of the machine tool, Japanese companies will pay more attention to improving the traditional structure, reducing the auxiliary time, reducing the size and weight of the machine tool, and reducing the energy consumption. The main purpose is to reduce the machine tool. the price of.
Finishing, milling, drilling and other processes, including tapping. In most cases, the part can be fully loaded in a sub-clamp. The machine uses a reverse spindle layout to ensure that the positions of the two spindles are highly synchronized. Thanks to the total axis and Y), the correct orientation can be maintained when machining the workpiece from both sides.
The turret head of the 15 station, the time per rotation of the station is 0.2 s. The swivel tool can be installed at all stations if necessary (the transmission power is set to different system parameters for the two channels to achieve between the channels Independent control relationship. The user program is written under different channels, and only the user program related to the control of this channel can be written under each channel.
As a link between the two channels, a wait function is used in the design. This function is used to wait for another channel in the automatic machining process. If the accessory's forward and reverse controls are in channel 1, and the accessory's transposition control is in channel 2, therefore, when using the accessory for automatic machining, the wait function must be used to coordinate the action between the two channels. A three-digit code is specified in a specific block of the machining program. When the attachment in the second channel is changed to the station to be processed, it waits until the program in the first channel finishes the attachment and advances the part. After processing, the program in the two channels simultaneously executes the next block of the block where the code is located. It can be seen that by waiting for the function, the user can coordinate the control between the two channels according to the requirements of the processing technology, adjust the production rhythm between the two channels, and effectively improve the productivity.
3.2 Double spindle control Because the maximum speed of the main spindle is 10000 r/in and the orientation and indexing function are required for machine tool processing, the FANUÎ± spindle servo system is selected for both the main and the sub-spindle, and the main and sub-spindle are both Equipped with a position encoder. In this way, not only can the main spindle reach a speed of 10000r/in, but also the orientation function of the spindle can be conveniently realized with 19, and the limited indexing of the spindle can be realized.
The encoders of the main and sub-spindle and the main and sub-spindle are respectively 1:1 drive. In this way, the user only needs to set a special code in the first channel to put the system into the spindle synchronous control state. Then, only need to control the speed of the main spindle, the sub-spindle will automatically adjust the speed to the same speed as the main spindle, and the phase is the same. Thereby the automatic transfer of the arbitrarily shaped parts between the main and sub-spindle is realized.
3.3 Tool change control According to the structural characteristics of the machine, the X1 axis and Y1 axis are both the feed axis and the tool change axis. In the configuration of the system, both the X1 axis and the Y 1 axis are selected as the N control axis. In the control design of the machine tool, the user macro program is used for tool transposition control, and the relevant conditions of the user macro program call are set in the system parameters to ensure the reliability and accuracy of the tool transposition. At the same time, because the system's Y-axis offset function is selected, all the tools on the machine can simultaneously compensate the geometry and wear of the tool in the X, Y, and Z directions, which greatly facilitates the user's use.
4 Conclusion Through the prototype trial, the FANU 0TT system can fully meet the performance requirements of all aspects of the KE2 machine. The maximum speed of the main spindle of the machine tool can reach 10000r/in, the maximum speed of the sub-spindle can reach 5000 r/in, and the rapid moving speed of each servo axis is 10/in except for the X1 axis. The other axes are 12/in. The maximum speed of the power tool is 3000r. /work.
Author: Dongming Yu, four provinces Dujiangyan City, Ningjiang Machine Tool Factory (editor Dong Yaping) (Revised closing date: 20000) The company's W120GT N-type twin-spindle lathes, dedicated to turning the workpiece quenching (hardness than 45HR), can replace grinder. The bed is made up of 2 separate parts for vibration isolation.
Hitachi Seiki's S20 vertical N lathe has a traditional layout and is equipped with a series of blank stock and parts libraries. Its distinguishing feature is that the spindle part is equipped with a moving device and a hydraulic drive chuck, so that the workpiece can be loaded and unloaded without special equipment.
Sakurai's ubi7 is equipped with a three-story warehouse containing seven headstocks on its power slide.
Pressing the command from N, the upper headstock can be rotated around the Z axis and can be moved from the upper two layers to the lower layer. After the spindle box enters the lower layer, it can be rotated and transferred to the working position of the power slide. The movement time of the headstock in the warehouse and the time of moving the work station from the warehouse partially coincide with the processing time.
The multi-spindle box has an exchange time from cutting to cutting of 5 s. The power slide with spindle head has a stroke of 550 and a maximum movement speed of 24 / up to 11 kW. A sensor for checking the integrity of the cutting tool is installed in the module structure.
A typical representative of a Japanese centerless grinding machine is the Ohiya machine tool series. Its characteristics: the grinding wheel and the guide wheel are mounted on a double-bearing main shaft with precision rolling bearings. The bearings are lubricated with oil mist. The bed shell is made of honeycomb ribs, which can make it have good vibration absorption and satisfactory heat dissipation.
The combination of the rolling guide and the ball screw drive ensures smooth movement and positioning accuracy. The drive of the dressing mechanism uses an electric motor instead of a hydraulic transmission to reduce the source of thermal deformation. The stepless speed regulation range of the guide wheel is 10~250r/in. It is easy to adjust the machine when the workpiece type changes.
Author: Li Liangfu, Xishan City, Jiangsu Province Qianqiao 7602 Golden Globe building, metallurgical machinery factory in Wuxi, Zip Code: 151 (edit Zhao Honglin)
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