NC transformation of 1271 machining center in Russ

  • Detail

Russia ТФ Numerical control transformation of 1271 machining center ТФ The 1271 processing center is the second bed imported from Russia by Anhui FAW chassis factory in 1994, with a purchase price of 250000 yuan. Due to the poor reliability of the CNC system, the CNC system can not work normally after less than one year of use, resulting in the paralysis of the entire machining center, which has a great impact on the production of their factory. And Russia ТФ At present, 1271 processing center is not widely used in China, and there is no perfect after-sales service system. So the factory entrusted us to renovate the equipment

1 ТФ Features of 1271 machining center

ТФ 1271 processing center is a product of Russia in the 1960s and 1970s. The electrical part of the machining center has poor performance, the CNC system is very backward, and the internal components of the system are mostly separated components. The system has huge volume, poor stability and high failure rate. Compared with the CNC systems produced at home and abroad, it has fewer functions, such as communication, single segment, skip segment, processing graphic display and so on, which brings some inconvenience to users; The motor control components and circuits of strong current parts such as hydraulic pressure, cooling, lubrication and spindle have been aged; Some position detection switches of the machining center are non-standard components, and similar switches cannot be found as spare parts in China

a large number of insiders from coal enterprises and other units believe that the mechanical part of the machining center has good performance and less wear of various parts, and can better meet the design requirements of the machine tool. Its mechanical design has three characteristics. The capacity of the tool magazine is 12 knives. The selection and positioning of each knife is roughly controlled by the electrical control, and finally is precisely positioned by the mechanical stop; The spindle motor is a three-phase asynchronous motor, which can only work at the rated speed, and then select gears with different tooth numbers to form 18 speeds; The spindle orientation is mechanical. The spindle is directly turned to the tool change position by hydraulic drive through the control of the hydraulic valve

2 transformation scheme

replace the CNC system and adopt the cme1000 system developed and produced by Beijing Machine Tool Research Institute. The system is an economical numerical control system with good performance price ratio. It is widely used in lathes, milling machines and machining centers. Compared with the original system, the volume of the system 2. The inconveniences of the traditional zigzag experiment: (1) the zigzag experiment position of the oil cylinder mounted universal experimental machine is high and small, with a good man-machine interface, high positioning accuracy, strong functions, increased communication function, and can communicate directly with the computer, providing convenience for offline programming; The display function of processing graphics allows the programmer to see the simulated processing curve when the machine tool does not act, making the debugging program extremely safe and convenient; Single segment function: it is safer to use single segment function during workpiece trial cutting; The section skipping function provides conditions for the flexible application of the same program; The locking function of the machine tool, which is matched with the graphic display function, makes debugging and processing very convenient; Manual function, it can continuously adjust the position of the tool tip during machining and tool setting, which is much more convenient than the inching function adopted by the original machine tool

for the strong current part, the motor itself has good performance, but the components and cables of the control system are aging, so the motors of the original machining center, including the spindle motor, cooling motor, lubrication motor and hydraulic motor, are retained, and other parts are replaced

for the position detection switch, the travel switch and proximity switch of the original machining center are all non-standard parts, and all these non-standard detection switches will be replaced with domestic standard parts

all mechanical parts shall be kept in good condition

the total transformation cost is 105000 yuan, the cost of purchasing the original processing center is 250000 yuan, and the cost of purchasing a processing center of the same grade as that after transformation is 800000 to 1000000 yuan

the 18 speed change of the main shaft is realized by three groups of sliding gears. The three sets of sliding gears are controlled by three hydraulically driven shift forks. During gear shifting, the spindle motor steps to ensure that the gears can mesh quickly and accurately. The main shaft is the largest aluminum lithium alloy production enterprise in the United States and the world. When the motor has no stepping function, it is easy to have the top gear phenomenon in the speed change process, resulting in gear failure. The lead screw of the workbench is connected with the servo motor through a coupling. The lead screw and a part of the coupling are installed on the motor shaft respectively, and the two parts cooperate to realize transmission. The coupling belongs to the original machine tool. The fitting clearance between the two parts of the coupling is 200 m. the moving distance DL of the workbench when the motor rotates for one circle is 10mm. The coupling diameter D is 60mm. The error e caused by the fitting clearance D is e=d dl/d=10.6 (m). The error caused by the fitting clearance is 10.6 M. the design machining accuracy of the original processing center is 30 m. therefore, the error caused by the fitting clearance of the coupling is within the normal range, The coupling of the original machining center can continue to be used. As mentioned above, when shifting the gear of the spindle box, the spindle needs to be step-by-step matched, otherwise it is very easy to fail to shift. Generally, the three-phase asynchronous spindle motor has no stepping function, and the motor is supplied with three-phase AC. due to the long test cycle of high temperature creep and endurance, the motor rotates at high speed. Through the control of PLC, the three-phase winding resistance of the motor is connected with low DC pulsating voltage to realize the stepping function of the spindle motor. The principle is shown in the figure above

4 conclusion

we are talking about Russia ТФ During the transformation of 1271 machining center, all the equipment and components used in the transformation from numerical control system to position detection switch and operation panel are domestic products. On the one hand, due to the rapid development of domestic CNC industry in recent years, some CNC products of some CNC manufacturers can be equivalent to foreign similar products in quality; On the other hand, adopting domestic products can save costs and facilitate maintenance. After the transformation, the machining center has been working normally for one year. It meets the design requirements of the original machining center in terms of machining accuracy and function. Moreover, the transformed machining center has higher positioning accuracy than that before the transformation. It also adds a variety of functions, such as communication function, single segment execution function of NC program, segment skipping execution function and manual function. The NC transformation of old machine tools or machining centers can make them become advanced NC machining equipment from obsolete obsolete equipment. The transformation cost is only equivalent to 10% of the cost of purchasing a similar new equipment. The NC transformation of old machine tools or machining centers can bring good social and economic benefits

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