At present, stamping machines at home and abroad, such as punching machines, need to make their punches reciprocating linear motion. The power of the existing mechanical press (punch) comes from the rotary motor, which requires a complex set of conversion mechanisms to convert the rotary motion into the required linear reciprocating motion. In order to obtain sufficient punching force, an energy storage device is required. Big flywheel.
Therefore, the press has many components, complicated structure, bulky volume, high noise, long production cycle, inflexible use, and prone to personal injury accidents. This kind of mechanical punching machine, its drawbacks have not been able to fundamentally change.
The new electromagnetic punching machine (linear motor punching machine) developed in this paper uses linear motor technology to directly convert electrical energy into mechanical force. It does not need to pass any intermediate conversion mechanism to realize the reciprocating motion of the punch.
Although there are similar studies at home and abroad, there are no results and product identification in this area, and many patents have been granted, and they have been put into small batch production with remarkable results. Compared with the traditional mechanical punching machine, the new electromagnetic punching machine has the advantages of simple structure, small volume and light weight; no periodic mechanical noise; pulse type work, energy saving effect; stamping tonnage, frequency and speed are adjustable; There are various installation methods; easy to control, can achieve a variety of protection functions.
Second, structure and working principle
1. The basic structure of the electromagnetic motor driven by the linear motor is shown in Figure 1. It is mainly divided into three parts, namely the fuselage part, the linear motor part and the control system part.
2, the basic working principle
The basic working principle of the structure is briefly described as follows:
Plug in the power, start the power switch, and set the punch tonnage. If it is automatic stamping, you need to set the punching frequency and then start the stamping button, otherwise it will be processed manually. When the button is turned on, the linear motor primary 2 will be energized to generate an electromagnetic force, causing the secondary 3 to drive the mold frame 7 downward to punch the workpiece. At the end of the punching, the secondary 3 returns to the initial position under the pull of the reverse electromagnetic force and the return spring, waiting for the next punch. If the button is in automatic crossover, the punch will continue to operate at the set frequency until the button is closed. The punch is only controlled by the button unless the safe power-off device needs to be stopped midway.
Third, linear motor and control technology
1. Linear motor design The key part of the electromagnetic punching machine is the linear motor. In general, linear motors are often used as devices to drive intermittent operation, and their duration is often below 25%. Now, when a linear motor is used to drive a punching machine, its continuous rate is much higher, and it is basically in a continuous working state. Therefore, higher requirements are placed on the design and manufacture of linear motors.
First of all, in the basic type and structure of linear motors, we mainly use linear induction motors. The structure consists of cylindrical, planar bilateral and single-sided. Specially designed linear motors, such as housing movements. The special structure type such as the grade type [6]; secondly, in the design of the electromagnetic scheme, the computer is used to optimize the design of multiple schemes; finally, some new attempts are made on the materials and structures of the primary and secondary. Through the above work, the performance of the linear motor is completely suitable for the working needs of the electromagnetic punching machine.
2, control system
The connection between the linear motor and the power supply of the electromagnetic punching machine is realized by the non-contact switch-solid-state breaker (SSR). The control system of the press machine is an important part. It consists of four small parts, namely the 1 power supply part. 2 count and display part; 3 trigger drive part; 4 automatic protection part. The control system block diagram is shown in Figure 2: The control system can achieve the following functions:
(1) The stamping tonnage is adjustable;
(2) The stroke is adjustable;
(3) Optional manual and automatic stamping;
(4) The punching frequency (20 to 300 times/min) can be selected.
(5) It has various electrical, thermal and mechanical fault detection and protection functions.
The control system with the above functions should pay special attention to solve two problems, which is to determine the optimal triggering time and the optimal conduction time of the motor. The above two problems are mainly solved by computer simulation and detection using a single-chip control circuit. The block diagram of the control circuit is shown in Figure 3.
Fourth, test and results
We designed and developed four prototypes of 5, 10, 31.5 and 50kN, and the test data is basically consistent with the design values. The impulse error is between 1% and 5%. We tested and tested the punching force of the linear motor punching machine and the temperature rise of the press body and the primary and secondary of the linear motor. The test system is shown in Figure 5.
We also tested the pulse power and total power consumption of the test. The test run time is generally above 4h. The user runs for more than 8 hours. In the test of the force, temperature and energy consumption of the electromagnetic punching machine, how to accurately determine the punching force is one of the tasks of this paper. Because the punching force of the electromagnetic punching machine is a kind of transient force, its punching speed is fast and the transient process is short (ms level). Therefore, this paper adopts digital signal processing technology and passes computer aided test system to accurately measure the force. Data, the following is a description of the force test system.
1. Principle and method of force test system The transient test system of electromagnetic punching machine is mainly composed of three parts, namely pressure sensor, amplification unit and record detection unit. The principle of test system is shown in Fig. 5.
Before the test, the pressure sensor is statically and dynamically calibrated. Taking the 10kN electromagnetic punching machine as an example, the static and dynamic calibration coefficients KF of the sensor are 0.07258V/kN and 0.07351V/kN, respectively, and the relative error is 1.3%. Therefore, It is believed that the pressure sensor has the same static and dynamic output characteristics.
During the test, the sensor is fixed on the base of the linear motor driven punching machine, and the stamping is performed. When the sensor is subjected to the transient action of the press, a weak pulse signal is generated immediately, and the signal is amplified, converted, detected and processed. The required transient force waveform, which can directly display the magnitude of the transient force through the display.
As an auxiliary data, an acceleration sensor is installed at the top of the punching rod. By using the correspondence between the transient force signal and the acceleration signal, the noise signal can be easily distinguished from the transient force signal. Figure 6 is a test curve of the impulse of a 10KN linear motor driven punch.
2, test results
For the temperature test, we placed them at 7 points on the coil, core, fuselage, shaft, etc. with a thermocouple, and then tested with a temperature tester (see Figure 5). We measured a total of 7 points of temperature, at room temperature of 30 ° C, the motor coil recorded in the table, the secondary temperature is 1h after the stable temperature. The measurement of electrical energy is carried out using an electric meter. Table 1 compares some test data of a 10kN electromagnetic press with a mechanical press.
In addition, from the current small batch production, the manufacturing cost of the electromagnetic punching machine is also lower than that of the mechanical punching machine.
V. Conclusion
Through the above discussion, and based on the test results and small batch production, the design of the linear motor driven punch is feasible and the control system is stable. This paper considers that the electromagnetic punch driven by linear motor has many advantages mentioned in the paper compared with the small tonnage mechanical punch. In some suitable occasions, it will be more popular than the mechanical press.
Therefore, the press has many components, complicated structure, bulky volume, high noise, long production cycle, inflexible use, and prone to personal injury accidents. This kind of mechanical punching machine, its drawbacks have not been able to fundamentally change.
The new electromagnetic punching machine (linear motor punching machine) developed in this paper uses linear motor technology to directly convert electrical energy into mechanical force. It does not need to pass any intermediate conversion mechanism to realize the reciprocating motion of the punch.
Although there are similar studies at home and abroad, there are no results and product identification in this area, and many patents have been granted, and they have been put into small batch production with remarkable results. Compared with the traditional mechanical punching machine, the new electromagnetic punching machine has the advantages of simple structure, small volume and light weight; no periodic mechanical noise; pulse type work, energy saving effect; stamping tonnage, frequency and speed are adjustable; There are various installation methods; easy to control, can achieve a variety of protection functions.
Second, structure and working principle
1. The basic structure of the electromagnetic motor driven by the linear motor is shown in Figure 1. It is mainly divided into three parts, namely the fuselage part, the linear motor part and the control system part.
2, the basic working principle
The basic working principle of the structure is briefly described as follows:
Plug in the power, start the power switch, and set the punch tonnage. If it is automatic stamping, you need to set the punching frequency and then start the stamping button, otherwise it will be processed manually. When the button is turned on, the linear motor primary 2 will be energized to generate an electromagnetic force, causing the secondary 3 to drive the mold frame 7 downward to punch the workpiece. At the end of the punching, the secondary 3 returns to the initial position under the pull of the reverse electromagnetic force and the return spring, waiting for the next punch. If the button is in automatic crossover, the punch will continue to operate at the set frequency until the button is closed. The punch is only controlled by the button unless the safe power-off device needs to be stopped midway.
Third, linear motor and control technology
1. Linear motor design The key part of the electromagnetic punching machine is the linear motor. In general, linear motors are often used as devices to drive intermittent operation, and their duration is often below 25%. Now, when a linear motor is used to drive a punching machine, its continuous rate is much higher, and it is basically in a continuous working state. Therefore, higher requirements are placed on the design and manufacture of linear motors.
First of all, in the basic type and structure of linear motors, we mainly use linear induction motors. The structure consists of cylindrical, planar bilateral and single-sided. Specially designed linear motors, such as housing movements. The special structure type such as the grade type [6]; secondly, in the design of the electromagnetic scheme, the computer is used to optimize the design of multiple schemes; finally, some new attempts are made on the materials and structures of the primary and secondary. Through the above work, the performance of the linear motor is completely suitable for the working needs of the electromagnetic punching machine.
2, control system
The connection between the linear motor and the power supply of the electromagnetic punching machine is realized by the non-contact switch-solid-state breaker (SSR). The control system of the press machine is an important part. It consists of four small parts, namely the 1 power supply part. 2 count and display part; 3 trigger drive part; 4 automatic protection part. The control system block diagram is shown in Figure 2: The control system can achieve the following functions:
(1) The stamping tonnage is adjustable;
(2) The stroke is adjustable;
(3) Optional manual and automatic stamping;
(4) The punching frequency (20 to 300 times/min) can be selected.
(5) It has various electrical, thermal and mechanical fault detection and protection functions.
The control system with the above functions should pay special attention to solve two problems, which is to determine the optimal triggering time and the optimal conduction time of the motor. The above two problems are mainly solved by computer simulation and detection using a single-chip control circuit. The block diagram of the control circuit is shown in Figure 3.
Fourth, test and results
We designed and developed four prototypes of 5, 10, 31.5 and 50kN, and the test data is basically consistent with the design values. The impulse error is between 1% and 5%. We tested and tested the punching force of the linear motor punching machine and the temperature rise of the press body and the primary and secondary of the linear motor. The test system is shown in Figure 5.
We also tested the pulse power and total power consumption of the test. The test run time is generally above 4h. The user runs for more than 8 hours. In the test of the force, temperature and energy consumption of the electromagnetic punching machine, how to accurately determine the punching force is one of the tasks of this paper. Because the punching force of the electromagnetic punching machine is a kind of transient force, its punching speed is fast and the transient process is short (ms level). Therefore, this paper adopts digital signal processing technology and passes computer aided test system to accurately measure the force. Data, the following is a description of the force test system.
1. Principle and method of force test system The transient test system of electromagnetic punching machine is mainly composed of three parts, namely pressure sensor, amplification unit and record detection unit. The principle of test system is shown in Fig. 5.
Before the test, the pressure sensor is statically and dynamically calibrated. Taking the 10kN electromagnetic punching machine as an example, the static and dynamic calibration coefficients KF of the sensor are 0.07258V/kN and 0.07351V/kN, respectively, and the relative error is 1.3%. Therefore, It is believed that the pressure sensor has the same static and dynamic output characteristics.
During the test, the sensor is fixed on the base of the linear motor driven punching machine, and the stamping is performed. When the sensor is subjected to the transient action of the press, a weak pulse signal is generated immediately, and the signal is amplified, converted, detected and processed. The required transient force waveform, which can directly display the magnitude of the transient force through the display.
As an auxiliary data, an acceleration sensor is installed at the top of the punching rod. By using the correspondence between the transient force signal and the acceleration signal, the noise signal can be easily distinguished from the transient force signal. Figure 6 is a test curve of the impulse of a 10KN linear motor driven punch.
2, test results
For the temperature test, we placed them at 7 points on the coil, core, fuselage, shaft, etc. with a thermocouple, and then tested with a temperature tester (see Figure 5). We measured a total of 7 points of temperature, at room temperature of 30 ° C, the motor coil recorded in the table, the secondary temperature is 1h after the stable temperature. The measurement of electrical energy is carried out using an electric meter. Table 1 compares some test data of a 10kN electromagnetic press with a mechanical press.
In addition, from the current small batch production, the manufacturing cost of the electromagnetic punching machine is also lower than that of the mechanical punching machine.
V. Conclusion
Through the above discussion, and based on the test results and small batch production, the design of the linear motor driven punch is feasible and the control system is stable. This paper considers that the electromagnetic punch driven by linear motor has many advantages mentioned in the paper compared with the small tonnage mechanical punch. In some suitable occasions, it will be more popular than the mechanical press.
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