The CB3463 series lathe is a semi-automatic rotary lathe. Because of its programmability, it can meet a variety of processing requirements, so it is widely used in China's machinery industry. In the specific operation of machining, for different workpiece processes, as long as the pins on the operation panel are used, they are inserted into the corresponding pin holes and combined into the required machining. However, because its electrical control system uses a large number of relays, discrete electronic components and latch plates in the circuit, the electrical circuit is complicated, electrical faults occur, and maintenance is difficult. In today's rapid development of electronic technology, it is necessary and possible to use new technology to transform the original electrical control system to improve reliability, and to realize the manual, semi-automatic and fully automatic operation modes of the lathe, and to improve the machine tool. Advanced. After analysis, it is a good solution to use the programmable controller (PLC) to transform the electrical control system.
Function and Action of 1CB3463 Series Lathe Actuator The CB3463 series lathe consists of three parts: the front tool post mechanism, the rear tool post mechanism and the transfer mechanism. The front tool post and the rear tool post are relatively simple to perform. This article only describes the actions of the transfer mechanism and its action flow. There are 6 tool positions on the CB3463 series lathe, and the spindle motor is a two-speed motor. It can be combined into 8 kinds of speeds through 4 electromagnetic clutches in the gearbox. There are three kinds of work under the driving of two hydraulic solenoid valves. Advance speed; under the control of the hydraulic mechanism, the lifting, indexing, micro-lifting and falling movements can be realized. During the machining process, the operator can change the following process parameters through programming: work step, tool position, spindle speed, work speed, micro lift, and cooling, so as to achieve different working modes and meet the processing requirements of different processes. The operation flow of the lathe transfer training is shown in Fig. 1.
Selection of the 12th PLC in 2004 For the CB3463 series lathe, the selection of the PLC device must meet the following conditions: The adjustment of the process parameters can be realized by the DIP switch, which is convenient for the operator to modify the process parameters.
It can directly drive DC 24V solenoid valve, relay and indicator light load, and the capacity can reach more than 30VA.
20% fluctuations and 58 waveform distortion can combat transient high voltage surges.
Programming is easy, /0 points can meet the process requirements.
It can adapt to harsh environments, work stably and reliably, easy to maintain, and low failure rate.
According to the above conditions and the usual application experience, and considering the price factor, select the relay output type PLC of Mitsubishi F1 series. The calculation and optimization of I/O point of PLC The design of electric control system of CB3463 series lathe can be divided into two functional blocks. Consider, one is the operating mode that controls the operation of the machine; the other is the programming mode through which various process parameters are set.
3.1 Operation mode input points are: 12 button switches, occupying 18 points; 11 travel switches, occupying 11 points; a total of 29 points.
The output points are: 13 hydraulic solenoid valves, occupying 13 points; 2 intermediate relays, occupying 2 points; 6 indicator lights, occupying 6 points; a total of 21 points.
3.2 Programming mode input points are: 7 pull code switches, 15 points; 2 buttons, 2 points; a total of 17 points.
The output points are: 1 indicator light, occupying 1 point, a total of 1.
Since the operation mode and the programming mode do not work at the same time, a reasonable design circuit can realize that the same input point plays different roles in different ways, so that 12 points in the input point can be shared with other points, thereby using 12 less point. With this optimized design method, a total of 34 input points for the PLC and 22 output points are required, with a total of /0 points and 56 points.
PLC, the input of this machine is 36 points, the output is 24 points, all meet the design requirements.
*The design of the hardware circuit The electrical control system of the CB3463 series lathe is divided into two parts: the main circuit and the control circuit. The main circuit part mainly controls the operation of the spindle motor, the cooling pump motor and the oil pump motor. The spindle motor and the oil pump motor are directly started and fail. PLC control, and the high and low speed conversion of the spindle motor and the start and stop of the cooling pump motor are controlled by PLC; the control circuit part refers to the circuit connected to the PLC, which mainly realizes the writing of the signal detection parameters and the control of the executing device.
The design of this part of the circuit should reflect the line characteristics of the programming mode and the running mode, and there is a reusable optimization design at the input point of the PLC. The circuit design technique can be seen from the partial circuit given in 圄2.
At the time, only the programming code switch SA5 and the write button SA connected to the C01 line are valid; the input of the programming parameters is realized. When SAx is placed in the running mode, COM and C00 are connected. At this time, only the button SB6SB2, the stroke switch Sg4SQ22, and the selection switch SA2SA5 connected to the C00 line are valid, and various operations and controls of the machine tool during operation are realized. In order to prevent mutual interference of the common input point signals, diodes are used for isolation on the line.
PLC software programming PLC software is also composed of two major blocks: programming mode and operating mode. Programming mode realizes the input of process parameters; the operation mode can realize any choice of three working modes: manual, semi-automatic and automatic. In semi-automatic and automatic working mode, through software design, set up process parameters, tool selection and spindle shifting, transfer and advance and retreat functions. The overall flow of the software program is shown in Figure 3.
In semi-automatic mode, the program only runs one cycle of the specified step. The automatic working mode is to run 6 cycles of all 6 steps. In the program flow design of the automatic working mode, we use the step ladder instruction STL in the F1 series PLC. Using this instruction can effectively simplify the program and facilitate debugging. In addition, a large number of timer instructions are used in the program, in order to ensure reliable switching of various control methods, and appropriate "delay" is performed in some places to enable the entire system to operate reliably.
The program flow of the automatic working mode, the reading and writing program of the process parameters, the tool selection program of the transfer, and the rotation speed selection program of the spindle are not described here, and those who are interested can directly contact the author.
Conclusion The original electrical control system of semi-automatic lathe has been modified to optimize the circuit design, using trapezoidal 圄 programming and optimized distribution of input points, reducing I/O points, improving system performance, simplifying electrical circuits, and reducing faults. The incidence rate increases the efficiency of the machine tool and increases the production efficiency.
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