An example of economical numerical control transformation of ordinary lathe for water conservancy and electric power machinery Li Guonong China Changcheng Aluminum Corporation, Zhengzhou 450041, Henan Province, has obtained high economic benefits. Taking the CNC modification of the 6140 type lathe as the 洌, in the principle of minimizing the modification of the lathe, the anti-interference of the control part is strong, and the transformation cost is low, the lathe is numerically modified. The transformation project has the control of the number of revolutions of the spindle and the steering; the control of the amount of the cutter is the control of the rotation of the cutter and the determination of the precision of the working guide.

Practice 1 is clear. The modified machine tool meets the needs of technological development. Increased productivity and product accuracy, increased equipment adaptability and profile processing. 1.2 Economic analysis Due to the price of new machine tools, sub-investment is huge. If the old machine tools are all replaced with new machine tools, it will cost a lot of money. The replacement machine will be idle and wasteful. If the old machine is modified by CNC technology, it can save more than 50 funds compared with the purchase of a new machine. The price of the economical numerical control device is only 1 to 15 of the full-function numerical control device, and the users can take the responsibility. This has created a new road for the technological transformation of small and medium-sized enterprises with tight capital, and also has a large-scale The enterprise has produced a relatively hot attraction. 1.3 Market analysis According to 1 data. Ordering new CNC machine tools has a long lead time and often does not meet user needs. Therefore, the numerical control transformation of the machine tool has become the main supplementary means to meet the market demand. 1.4 Production analysis In the modern machinery manufacturing industry, the production of small and medium-sized batches and even single-piece production accounts for a considerable proportion. To complete these production tasks. It is nothing more than the choice of machine tools or CNC machine tools, which are the most suitable for the production needs of the 1.5 comprehensive analysis. It is not difficult to see from the above analysis, the numerical control technology for machine tool transformation is based on the modern technology of microelectronics. On the basis of the combination of traditional techniques, it has the advantages of high reliability, high flexibility, and easy realization of economical economy. For this reason, the microcomputer that enters the numerical control on the old machine can use the 8001 or his 35 single machine to improve the performance of the machine tool. Shanzhao has a large economic benefit from the integration of less capital investment. The performance price is better than the high reliability, and the function is fast and fast.

2, Shuo 140 type lathe CNC transformation example 16140 type ordinary cot is the stereotyped product manufactured by Shenyang No. 1 Machine Tool Plant. Compared with other ordinary lathes, it has the characteristics of good performance, advanced operation and light weight, and is widely used in China's machinery manufacturing industry.

The drive system of the bed. The upper part of the mountain is composed of 2 parts. It is a 屯 motion transmission chain. Its function is to transmit the motion and power of the power source motor to the main shaft, so that the main shaft drives the workpiece to rotate to achieve the main motion, and meet the requirements of the shifting and reversing of the horizontal lathe spindle. It is a feed motion transmission chain, which is used to realize the longitudinal and lateral movement of the tool holder and the movement of the thread and the power is transmitted from the spindle motor to the tool holder via the spindle spindle feed motion transmission chain slide.

The purpose of transforming such a bed is to adjust the viscosity and automation of the original boring machine to achieve rapid adjustment and still maintain the versatility of the lathe. It is to improve the function of the original lathe and accurately process the rotation of any surface by numerical control. body.

2.1 The design requirements of the NC transformation are adopted by the system, and 51 is used as a computer system to control the computer system. It consists of several parts such as the keyboard of the microcomputer and the interface of the display 13 and the photoelectric isolation servo motor drive circuit. CNC system hardware box attached 1., software. It consists of several parts, such as the main module subroutine module and the interrupt processing module. When working, the keyboard enters the part processing program. The 8-digit digital display shows the working status and related parameters. Before the work, the band switch is selected to be programmed manually. The microcomputer performs processing on the data. The step pulse is output by the interface.

Wood rolls have as few changes as possible on the lathe. The control part requires the principle of strong anti-interference and low cost. According to technical requirements. Before the transformation, the performance data of the lathe should be mastered, so as to determine the precision of the lathe itself and the numerical control transformation of the ordinary lathe for the modified lathe, the four internal boundaries, the lathe of the lathe, and the number of revolutions. The information is transmitted to the computer system, and the amount of the tool in both directions of the lathe is controlled. Usually, the computer-controlled motor directly drives the drive wire to control the rotation of the table. It is a computer-controlled motor to achieve the corner of the 4 lathes. The guide rails are recognized. When the guide rails are modified, the precision of the factory can be restored by grinding and scraping. This is economical. way of doing. According to the requirements of producing high-precision products, the guide rails can also be transformed into hydrostatic guide rails or rolling race guide rails to support the grading level and level 0.

Report the performance requirements of CNC lathes. Determine the rapid positioning speed of the feed motion. The 7-axis is the 3-axis pulse. 2.2.2 System Motion Mode The CNC system can be divided into the point control system point linear control system and the continuous control system according to the motion. Because the tool of the 06140 lathe is to move along a specified route at a given rate to machine a linear arc or other contoured part, the motion of each coordinate axis has a certain function relationship, so a continuous control system is adopted. The continuous control system has the function of the point control system. Therefore, the positioning method can be controlled from the target.

2.2.3 Servo system Servo system realizes position servo control with open-loop closed-loop semi-closed loop mode. The open loop control servo system has a problem of low control accuracy. However, the strict correspondence between the angular displacement of the stepping motor and the input pulse makes the step error not accumulate. The speed of the stepping motor and the input pulse frequency are also strictly related to the lamp. The chaos has the characteristic that it does not vary with the fluctuation of the environmental conditions of the current and voltage load in the range of the load energy. The open-loop system controlled by the stepper motor does not have the position detection and feedback control, and the structure is relatively simple. The realization and adjustment of the easy factory control system. Khan 1. With the development of electronic technology and computer control technology. Zhuang has also made encouraging progress in improving the control performance of stepper motors. Therefore, within a certain range, this open-loop servo system using a stepping motor as a driving actuator can meet the processing requirements, and is suitable for the overall design of the accuracy requirement 2.2. 2.2.1 Computer system 1 commercial load, control 1 show name running 8 祜 祜 祜 borrow 15152 brain magnetic 7 缫塍 ,, shout 3. buy. and also.闭环nbsp; Although the closed-loop semi-closed loop control provides the possibility of high-precision position servo control, the position detection feedback comparison and servo amplification are added in the system. In addition to adding 1 volume and complexity to the installation and commissioning. From the perspective of control theory. To achieve good steady-state and dynamic performance of the closed-loop system, the difficulty will be greatly improved. Considering that it is retrofitted on a common lathe, the accuracy requirements are not very high. In order to simplify the structure and reduce the cost, we use a stepper motor open-loop servo system controlled by a microcomputer.

2.2.4 Straining mechanism drive mode guide. Due to the use of an open-loop system with low precision requirements, the positioning accuracy and sensitivity of the sliding guide can reach about 101 without grinding, which can meet the requirements after the transformation. Therefore, it is still possible to use the open type, the sliding guide rail and the dovetail type sliding guide rail of the original bed, and it is not necessary to select a rolling guide rail with a high cost and a static twist guide rail with a structure of 4, and a screw drive. The original screw of the 乍 Mu is a swaying screw drive. The main disadvantage is that the mechanical efficiency is low, generally = 3,03, which is quite different from the transmission accuracy requirements after the transformation. In addition to high positioning accuracy, CNC lathes should also have good dynamic response characteristics.

The characteristic of the rolling screw pair is transmission efficiency=9296; the gap between the screw nut can be eliminated by pre-tightening; the movement is stable, the transmission precision is high, the reversible friction is small, and the service life is long; the manufacturing process is complicated and the cost is high. . After a comprehensive comparison, the CNC machine tool uses a rolling screw mechanism. According to the maximum dynamic load of the human 614 lathe, and considering the size of the lathe screw for 40,12, the ball screw diameter is 40, the model is 40, 63.52, its rated dynamic load is 19, and the strength is enough for the main drive. The spindle system retains the original lathe spindle components, but a spindle pulse generator is additionally mounted on the spindle for the threaded iJH.To feed drive. Since the modified longitudinal feed mechanism uses a stepping motor as the drive component, it is necessary to remove the feed box of the original lathe, the slide bar operation lever, and the ball screw nut pair to replace the original trapezoidal thread nut nut pair. The ball screw is still installed at the two positions of the original trapezoidal screw. The roller bearing is fixed at the ends, and the boring of the machine end is still adopted. Since the frictional flash of the ball screw is smaller than the original screw, the overall rigidity of the longitudinal feed is increased. The gearbox is fixed to the tailstock end bed. In order to facilitate the installation of the ball screw pair, the screw shaft is not integral, but is divided and is rigidly coupled by a sleeve.

On the carriage, the original square frame is changed to the station programmable automatic indexing tool holder.

The horizontal feed mechanism still retains the manual mechanism. The original support structure is also reserved for micro-feeding and pre-operation. Install the vertical and horizontal rapid feed button and emergency stop button on the stepper motor and the reducer. Therefore, emergency stop should be performed when the machine needs to be adjusted and the accidental conditions are met. In order to meet the minimum step requirement, the motor adopts the phase six-pulse working mode to comprehensively consider the torque and the working frequency, and selects the 083 type DC stepping motor.

gear drive. Considering that the step angle of the stepper motor and the lead screw guide can only be selected according to the standard. In order to achieve the resolution requirements, the vertical and horizontal feed mechanism needs to adopt the stage gear to reduce the gap by using the wrong tooth method. 2.3 Hardware Circuit Design The hardware circuit of the machine numerical control system consists of four parts of the main controller bus memory and interface.

2.3.1 The same type of main controller. Among them, 85; 41; 8751 in-line 仃 4140, 8, 31 pieces have no program memory, and must be used to extend Yanghe and the team outside the film. The commonality of the above three varieties is 32 lines, there are two 16-bit timers, there are 5 interrupt sources, there is a full-duplex serial communication interface, there are a total of 128 bytes on the chip, there are 21 Special function registers, etc. Can be 5 milk 51 series tycoon machine is a strong function of the micro-computer core of a towel. It is widely used in the field of intelligent instrument clothing CNC. 2.3.2 Programmable interface chip 8155 This chip and computer connection is a simple interface that is widely used in microcomputer systems. Chip, it has a 40-pin dual in-line civilian-view 101 expander, including 256 bytes of video memory, 6 bits, 2 8-bit programmable 10 interfaces, 4 bits of programmable timing Counter.

2.3.3 Photoelectric isolation circuit In the stepping motor drive circuit, the pulse signal is controlled by the power amplifier factory to control the motor excitation winding. The driving voltage required for the 1 input motor is about 80, and the current is about 6, if the output signal and the power amplifier are Direct connection will cause strong electrical interference.

Therefore, an isolation circuit should be connected between the interface circuit and the power amplifier.

2.3.4 Stepper motor drive circuit The function of the motor drive circuit is power amplification. The weak signal sent by the photoelectric isolation circuit is amplified by power, becomes a strong electric signal, and directly drives the stepping motor.

When the control pulse comes, 1., 4 is fully dimmed, and the secondary side of the pulse transformer 1 produces a pulse current of a predetermined width, so that 2 is turned on, so that 5 is reverse biased, and the low voltage and the winding 141 are cut off. The high-voltage power supply 0 passes through 21 for the stepping motor, and the phase winding current disappears, so that 2 is cut off and the winding is cut off. Pass 5 for. The power supply provides the set current required by the motor.

By adjusting the magnetic core of the pulse transformer and; 5 can change the high-voltage power supply 2.3.5 keyboard display 5 interface circuit keyboard display device CNC system often human-machine interaction, the peripheral device can complete the data input and the dynamic display of the computer state data Heart, using a determinant keyboard. That is, the wiring structure is composed of 1 wires, and the buttons are arranged at the intersection of the rows and columns.

The keyboard display circuit managed by the 55 interface chip is composed of a 58-key and a 7-bit 0 display. In order to simplify the circuit, the word line of the keyboard and the word position of the booklet control share a common interface, that is, the human interface of the 8155 chip. The line of the keyboard is controlled by the chip interface, and the font data of the display is controlled by the 8 interface of the chip.

2.4 software design software adopts modular design. The left module includes the main module subroutine module and the interrupt processing module.

2.4.1 Blue module management program, the program is executed after booting. Its work is initialized. Microcontroller D, D, timer counter initialization, keyboard data area buffer initialization, various software flags initialization, etc., whether there is a function key in the main template.

If there is, then the corresponding function subroutine block is transferred. Simplified Process 3 2.4.2 Subprogram Loose Block Design. As the workbench moves, the state on the keyboard. The 2+14 arrows in different directions are called different moving directions. In the software design, the 21 state unit in the key data area is the work station moving flag, 1 yuan. Such as the cabinet 4 small direction to drive the transmission module process.

Using the 8155 timer as the pulse signal source, the direction word is given in the module, and the mountain hardware loop is divided into 1 pulse distribution. Control the servo motor 4 rate step motor operation.

2.4.3 Interrupt Processing Module The interrupt processing includes 3 modules. According to the priority of different events in the microcomputer numerical control system, the priority queueing sequence is as follows.

Obvious. The overall scheme of the module flow 2.5 summary is that the meter uses 551 single-machine to calculate and process the data. The step pulse is output from the 10 0 interface, and the stepping motor is decelerated by the stage gear. The rolling screw is rotated to realize the longitudinal and lateral feeding motion. In addition, in order to ensure the function of the thread processing of the lathe and to prevent the occurrence of accidents, a protection circuit or the like is provided in the electric power. The system's process frame maintains the versatility of the lathe and increases the rotating body of the original lathe.

1 Liu Wenxin, Sun Xueli. Machine tool CNC technology elbow. Beijing Mechanical Industry Press, 1995.

Xi Shanghai Jiaotong Oxygen South China Institute of Technology, Shenyang Institute of Mechanical and Electrical Engineering, etc. The CNC machine is idle. Shanghai Shanghai Science and Technology Press. 1990.

3 Zhang Yigang, Xiu Lincheng Hu Zhenguang 851 single-chip application set up Harbin Institute of Technology Harbin Out of the box 6. CNC lathe after the improvement of the original set of home. 19 lathe accuracy and door movement private and private to achieve rapid adjustment (1) can still edit Wang Shuping on the 38th page parent speed in the range of pump efficiency is not changed within the range of the island pump performance parameters 伉 change according to the formula 1, do = seven CJ1.h, p centrifugal pump flow at loose speed, and power h, p centrifugal expansion to change the speed after the flow, head and power.

The structure for adjusting the operating conditions by changing the centrifugal speed is complicated. Additional equipment costs are higher. It is currently rarely used in coal mine production.

2.2.2 Reduce the number of multi-stage impellers or the outer diameter of the impeller to make the pump operate economically and reasonably. In the case of ensuring that there is a reserve head. It is necessary to eliminate too many affluent heads.

The standby head is a necessary margin for considering the performance degradation of the pump parts after wear and the speed reduction caused by the change of the grid frequency. The hall method for the 1015 to eliminate the head of the head can be the removal of the impeller or the outer diameter of the impeller. . It is better to dismantle the impeller only if the rich head outside the standby head reaches and exceeds the impeller. If the condition is limited, only the impeller can be removed, and the middle part does not change the shaft to turn the outer impeller of the impeller. There is still some rich head after the impeller is removed. in the case of. Or a fine-tuning method in the case of a rich head with insufficient impeller head.

Under the condition that the pump speed is constant, the performance of the pump after the outer diameter of the impeller is calculated as follows: A41D2, D1 points, the outer diameter of the impeller before and after turning; qv, h. points, the flow head power of the centrifugal pump before turning the impeller ;crh,p are the flow head power of the centrifugal pump after turning the impeller.

After turning the impeller. As the outer diameter of the blade becomes smaller. The line speed at the same angular velocity is reduced. The flow head of the pump should be reduced accordingly. In the range of 0.9 is 2. The more blades are turned. The more the pump flow head is reduced. The characteristic curve is similar to the curve for changing the centrifugal pump speed.

The turning impeller is a simple method that does not require additional investment and can adjust the operating conditions. Suitable units are promoted and adopted.

Editor Li Jianle

(Finish)

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