CN109967809B - A kind of wire electric discharge cutting electrode wire tension detection and LCD image display device - Google Patents

Abstract

The invention discloses a wire cut electrical discharge machining electrode wire tension detection and LCD image display device, which comprises a direct current power supply, a control module, an AD module, a strain type pressure sensor, an SD card module and an LCD display screen, wherein the direct current power supply is connected with the control module; the control module, the AD module and the strain type pressure sensor are sequentially connected to form a sampling circuit; the strain type pressure sensor is used for detecting the analog quantity of the tension of the electrode wire and converting the analog quantity into digital quantity through the AD module; the control module is used for receiving the digital quantity, calculating the relation between the digital quantity and the actual tension value, correcting the relation, processing the relation through an internal algorithm program according to the relation, and displaying an image and a numerical value (including the real-time tension and the tension average value of the previous n seconds) of the tension changing along with the time on an LCD display screen in real time; the SD card module is used for storing the tension value at regular time. The device can detect the tension of the electrode wire in real time and show the change trend in the form of images.

Description

A kind of wire electric discharge cutting electrode wire tension detection and LCD image display device

technical field

The invention relates to the technical field of electric discharge wire cutting, in particular to a wire electric discharge wire cutting electrode wire tension detection and LCD image display device.

Background technique

The basic working principle of WEDM technology is to use continuous moving thin metal wire (called electrode wire) as electrode to carry out pulse spark discharge to remove metal and cut and shape the workpiece. Its characteristics are as follows:

(1) There is no significant mechanical cutting force during processing. Regardless of the hardness and stiffness of the workpiece, as long as it is a conductive or semi-conductive material, it can be processed, but non-metallic conductive materials cannot be processed.

(2) Small holes and complex shape parts can be processed, but blind holes cannot be processed.

(3) The loss of electrode wire is small, and the machining accuracy is high.

(4) The slits produced during processing are narrow, and the amount of metal corrosion is small, which is conducive to the reuse of materials.

In order to improve the smooth movement of the wire EDM wire, it is usually necessary to apply a tension force to it. The magnitude of the tensioning force and the tensioning method have an important influence on the processing quality, efficiency and wire breakage.

In order to improve the machining quality and efficiency, the workpiece and the wire electrode need to maintain a constant tension during the machining process. The traditional WEDM machine does not have a tension detection device, and the tension of the electrode wire is constantly changing during the machining process, so the surface quality and machining efficiency of the workpiece to be machined will be affected.

In order to effectively avoid wire breakage, the tension of the electrode wire must be monitored in real time to take corresponding measures to avoid wire breakage.

In view of the above problems, a device is needed to detect the tension of the electrode wire in real time, and at the same time, it can perform relevant processing on the detected tension and display it intuitively through images, which is conducive to the subsequent control of the tension of the electrode wire during the wire transportation process, so that the It can be in a stable and balanced tension state with constant tension, improve the processing quality, reduce the probability of wire breakage, improve the processing efficiency and the service life of the electrode wire.

SUMMARY OF THE INVENTION

In order to solve the defect that the general traditional wire cutting machine cannot detect the wire tension, the present invention provides a wire EDM wire tension detection and LCD image display device based on STM32, which is applied to wire electric discharge machining. Real-time detection of the tension of the wire electrode is realized and the change trend is presented in the form of images, which is very beneficial to understand the processing situation and make adjustments in time, and provides a basis for subsequent improvement of processing stability.

To achieve the above object, the present invention adopts the following technical solutions:

A wire electric discharge wire cutting electrode wire tension detection and LCD image display device comprises a DC power supply, a control module, an AD module and a strain-type pressure sensor. The DC power supply is connected with the control module; the control module, the AD module and the strain-type pressure sensor are in sequence. Connected to form a sampling circuit; the strain pressure sensor is used to detect the analog quantity of the electrode wire tension during the wire feeding process, and transmit the analog quantity to the AD module; the AD module is used to receive the analog quantity of the electrode wire tension size and then convert the analog quantity Convert it into a digital quantity, and transmit the digital quantity to the control module for processing; the control module is used to calculate the relationship between the digital quantity and the actual tension value after receiving the digital quantity and correct it.

Further, it also includes an LCD display screen, the control module processes the corrected tension value through the internal algorithm program, and displays the image and numerical value of the tension changing with time on the LCD display screen in real time, including the real-time tension and the tension of the previous n seconds. average value. The programming in the control module displays the tension value in real time on the LCD display screen in the form of images, which makes the changing trend of the tension more intuitive and clear.

Further, it also includes an SD card module, which is used to store the detected tension value periodically for further data analysis and processing.

Further, the control module is an ARM controller, which completes the sampling of the AD value of the electrode wire tension, the calculation of the tension and the control of real-time image display through its internal programming.

Further, the algorithm for the average value of tension in the first n seconds programmed in the control module adopts an approximate solution. For example: to find the average tension of the first 100s at each moment, then the average value of the 101s = the average value of the 100s × 99% + the tension value of the 101s × 1%. This algorithm uses less variables and occupies less program space. It is especially suitable for long program operation.

Further, the average tension of the first n seconds is obtained according to the following formula:

Further, an electrode wire guide wheel is fixed on the strain-type pressure sensor, and the electrode wire guide wheel is wound with an EDM wire cutting electrode wire. The tension F acts on the force-bearing end of the strain-type pressure sensor through the electrode wire guide wheel, and the strain-type pressure sensor is deformed by force, the resistance strain gauge above it is stretched by force, and the resistance strain gauge below it is compressed by force, and transformed into The resistance change is converted into the corresponding voltage change through the measuring circuit, the analog quantity is converted into a digital quantity through the AD module, and then the measured tension can be obtained by conversion.

Further, the control module includes a power switch, a button battery with a power failure protection function, external expansion pins, an ARM main chip, a first LCD display wiring pin and a manual correction button, and the power switch is connected to the DC power supply and is the control module. Power supply, external expansion pins are connected to AD module, and the digital quantity converted by AD module is transmitted to the ARM main chip, converted into the actual tension of the wire EDM wire through the internal algorithm program, and displayed on the LCD screen in the form of an image Displayed, the first LCD display wiring pin is connected with the corresponding pin on the LCD display to display the image, and the manual correction button is pressed for correction.

Further, the LCD display screen includes the wiring pins of the second LCD display screen, the rectangular coordinate system, the real-time tension value value and change image, the average value and change image of the tension value 10s before the current point, and the average value and change of the tension value 100s before the current point. Image, the LCD display screen is connected to the control module through the second LCD display screen wiring pin to dynamically display the image, the X axis of the rectangular coordinate system is the time change axis, the Y axis of the rectangular coordinate system is the tension change axis, and the real-time tension value is dynamically displayed The value and change image, the average value and change image of tension 10s before the current point, and the average value and change image of tension 100s before the current point, every time the image on one screen is displayed, the content of the previous screen will continue to display the current image.

Beneficial effects:

1. The present invention is based on the wire tension detection technology, which overcomes the difficulty that traditional wire-cutting machine tools cannot detect wire tension.

2. The present invention adopts the multi-period LCD image display method of electrode wire tension, which has stable output graphics, sensitive response and adjustable detection period.

3. The electrode wire tension detection method adopted in the present invention can be directly applied to traditional wire-cut EDM machine tools and used for cutting without affecting the servo control system of the machine tool itself, and can realize real-time monitoring of electrode wire tension.

4. The SD card module of the present invention can periodically store the detected electrode wire tension value and export it in the form of a file for further analysis and processing.

5. The scope of application of the present invention is wide, not only applicable to wire EDM machine tools, but also applicable to other equipment that needs to use tension detection.

Description of drawings

Fig. 1 is the structural block diagram of the wire EDM wire tension detection and LCD image display device of the present invention;

2 is a schematic structural diagram of the wire EDM wire tension detection and LCD image display device of the present invention;

Fig. 3 is the detection schematic diagram of the wire EDM wire tension detection and LCD image display device of the present invention;

4 is a schematic diagram of a control module of the wire EDM wire tension detection and LCD image display device of the present invention;

5 is a schematic diagram of the LCD display screen of the wire EDM wire tension detection and LCD image display device of the present invention;

In the picture: 1-DC power supply, 2-Control module, 21-Power switch, 22-Button battery, 23-External expansion pin, 24-ARM main chip, 25-First LCD display wiring pin, 26-Manual Calibration button, 3-AD module, 4-strain pressure sensor, 5-SD card module, 6-LCD display screen, 61- second LCD display screen wiring pin, 62- Cartesian coordinate system, 63- real-time tension value value and change image, 64- average value and change image of tension 10s before the current point, 65- average value and change image of tension 100s before current point, 7- wire guide wheel, 8- wire EDM wire, 9- Resistance strain gauges.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

The present invention proposes a wire EDM wire tension detection and LCD image display device, as shown in Figures 1 and 2, which includes a DC power supply 1, a control module 2, an AD module 3, a strain-type pressure sensor 4, and an SD card Module 5 and LCD display screen 6, DC power supply 1 is connected with control module 2; control module 2, AD module 3 and strain-type pressure sensor 4 are connected in turn to form a sampling circuit; strain-type pressure sensor 4 is used to detect the electrode during the threading process. The analog quantity of the wire tension size, and the analog quantity is transmitted to the AD module 3; AD module 3 is used to receive the analog quantity of the electrode wire tension size, convert the analog quantity into a digital quantity, and transmit the digital quantity to the control module 2 for processing ; The control module 2 is used to calculate the relationship between the digital quantity and the actual tension value after receiving the digital quantity and correct it, and based on this, through the processing of the internal algorithm program, the LCD display screen 6 displays the image that the tension changes with time in real time. and numerical value (including real-time tension and the average tension of the previous n seconds); SD card module 5 is used to store the detected tension value regularly.

In the above technical solution, the pressure signal is used as the sampling signal, and the sampling circuit formed by connecting the control module 2, the AD module 3 and the strain pressure sensor 4 in sequence collects and calculates the pressure during the sampling period to obtain the magnitude of the pressure analog quantity, wherein The size of the pressure analog quantity refers to the value corresponding to the change in the resistance value of the resistance strain gauge 9 of the strain gauge pressure sensor 4 caused by the pressure change, and each analog quantity corresponds to a pressure value; the control module 2 is used to store and calculate the pressure value, Dynamically display three-cycle tension values and changing images on the LCD display 6: (1) real-time tension value values and changing images; (2) average tension values and changing images 10s before the current point; (3) 100s before the current point Tension mean values and variation images.

Among them, the average tension of the first n seconds can be obtained according to the following formula:

As shown in FIG. 3 , an electrode wire guide wheel 7 is fixed on the strain type pressure sensor 4 , the electrode wire guide wheel 7 is wound with an EDM wire cutting electrode wire 8 , and the upper and lower sides of the strain type pressure sensor 4 are pasted with resistance strain gauges 9 , the tension F on the wire EDM wire 8 acts on the force-bearing end of the strain-type pressure sensor 4 through the electrode wire guide wheel 7, the strain-type pressure sensor 4 is deformed by the force, and the resistance strain gauge 9 above it is subjected to Force stretching, the resistance strain gauge 9 below it is compressed by force, converted into a resistance change, and converted into a corresponding voltage change through the measuring circuit, and the analog quantity is converted into a digital quantity through the AD module 3, and then the result can be obtained by conversion. Measure the amount of tension.

As shown in FIG. 4 , the control module 2 includes a power switch 21 , a button battery 22 , an external expansion pin 23 , an ARM main chip 24 , a first LCD display wiring pin 25 and a manual calibration button 26 , the power switch 21 and the DC power supply 1 is connected to supply power to the control module 2. The button battery 22 has the function of power failure protection, and the data is still retained when the DC power supply 1 is disconnected. The external expansion pin 23 is connected to the AD module 3, and the digital quantity converted by the AD module 3 is transmitted to the ARM. The main chip 24 is converted into the actual tension of the electrode wire through the internal algorithm program, and is displayed on the LCD display screen 6 in the form of an image. The first LCD display screen wiring pin 25 is connected to the corresponding pin on the LCD display screen 6. The image is displayed, and the manual correction button 26 will be pressed to perform correction, which will remove the gravity of the wire guide wheel 7 to ensure that the obtained tension is the actual tension of the wire EDM wire 8 .

As shown in FIG. 5 , the LCD display screen 6 includes a second LCD display screen wiring pin 61, a Cartesian coordinate system 62, a real-time tension value value and a change image 63, a tension average value and a change image 64 before the current point 10s, and the current point The average value of the tension in the first 100s and the change image 65, the LCD display screen 6 is connected to the control module 2 through the second LCD display screen wiring pin 61 to dynamically display the image, the X axis of the Cartesian coordinate system is the time change axis, the unit is second, and the range is 20 seconds, increasing in turn, the Y axis is the tension change axis, the unit is Newton, the range is 14 Newton, the real-time tension value value and change image 63, the average value and change image 64 of the tension value before the current point 10s, and the tension value 100s before the current point are dynamically displayed The average value and the change image 65 will cover the content of the previous screen and continue to display the current image after each screen image is displayed. The SD card module 5 can regularly save the detected tension value for data analysis and processing.

Example:

Using traditional wire EDM machine tools, there is no wire tension detection function during processing, so it has a great impact on processing quality and efficiency, and wire breakage cannot be avoided. By adopting the present invention, the tension of the electrode wire can be detected in real time, and three curves and three tension values can be dynamically displayed in real time on the LCD display screen 6, corresponding to the real-time tension value, the average tension value of the previous 10s, the average tension value of the previous 100s, and the X axis is time, The range is 140s, the Y-axis is tension, the range is 14N, and the minimum accuracy is 0.05N.

Therefore, it plays a real-time monitoring role for the tension of the electrode wire. The tension change can be intuitively understood through the image displayed on the LCD. The detected tension can be further controlled to improve the processing quality, efficiency and avoid wire breakage. It will be the question of our follow-up research.

The parts not involved in the present invention are the same as the prior art or can be implemented by using the prior art.

To limit the protection scope of the present invention, those skilled in the art should understand that, on the basis of the technical solutions of the present invention, various modifications or deformations that can be made by those skilled in the art without creative work are still within the protection scope of the present invention. within.

Claims (7)

1. A wire electric discharge wire cutting electrode wire tension detection and LCD image display device is characterized in that: it comprises a DC power supply (1), a control module (2), an AD module (3) and a strain pressure sensor (4), The DC power supply (1) is connected with the control module (2); the control module (2), the AD module (3) and the strain-type pressure sensor (4) are connected in sequence to form a sampling circuit; The strain-type pressure sensor (4) is used to detect the analog quantity of the tension of the electrode wire during the wire running process, and transmit the analog quantity to the AD module (3); the AD module (3) is used to receive the tension of the electrode wire The analog quantity is converted into a digital quantity after the size of the analog quantity, and the digital quantity is transmitted to the control module (2) for processing; the control module (2) is used to calculate the digital quantity and the actual tension value after receiving the digital quantity. The relationship and correction; the device also includes an LCD display screen (6), and the control module (2) processes the corrected tension value through an internal algorithm program, and displays the tension change in real time on the LCD display screen (6). Time-varying images and numerical magnitudes include real-time tension and average tension for the previous n seconds. 2. The wire EDM wire tension detection and LCD image display device according to claim 1, characterized in that: it also comprises an SD card module (5), and the SD card module (5) is used for timing storage of the detected tension value. 3. wire electric discharge wire cutting electrode wire tension detection and LCD image display device according to claim 1, is characterized in that: described control module (2) is ARM controller, completes electrode wire tension AD value through its internal programming Sampling, calculation of tension and control of real-time image display. 4. The wire EDM wire tension detection and LCD image display device according to claim 1, characterized in that: the first n seconds of the internal programming of the control module (2) is an approximate solution for the average value algorithm of tension in the first n seconds. 5. The wire EDM wire tension detection and LCD image display device according to claim 1, characterized in that: an electrode wire guide wheel (7) is fixed on the strain-type pressure sensor (4), and the electrode wire guide The wheel (7) is wound with an EDM wire cutting electrode wire (8), the upper and lower surfaces of the strain-type pressure sensor (4) are affixed with resistance strain gauges (9), and the tension on the EDM wire cutting electrode wire (8) F acts on the force-bearing end of the strain-type pressure sensor (4) through the electrode wire guide wheel (7), the strain-type pressure sensor (4) is subjected to force to produce deformation, and the resistance strain gauge (9) above it is subjected to force Tensile, the resistance strain gauge (9) below it is compressed by force, converted into a resistance change, converted into a corresponding voltage change through the measuring circuit, and the analog quantity is converted into a digital quantity through the AD module (3), and then converted into a digital quantity through conversion. The magnitude of the measured tension can be obtained. 6. The wire EDM wire tension detection and LCD image display device according to claim 1, wherein the control module (2) comprises a power switch (21), a button battery ( 22), external expansion pins (23), ARM main chip (24), first LCD display wiring pins (25) and manual correction button (26), power switch (21) and the DC power supply (1) connection, power supply for the control module (2), the external expansion pin (23) is connected with the AD module (3), and the digital quantity converted by the AD module (3) is transmitted to the ARM main chip (24), The actual tension of the wire EDM wire (8) is converted by the internal algorithm program, and displayed on the LCD display screen (6) in the form of an image. The first LCD display screen wiring pin (25) is connected to the LCD display screen. The corresponding pins on (6) are connected to display the image, and the manual correction button (26) can be corrected by pressing it. 7. The wire EDM wire tension detection and LCD image display device according to claim 1, wherein the LCD display screen (6) comprises the second LCD display screen wiring pin (61), rectangular coordinates system (62), real-time tension value value and change image (63), tension average value and change image (64) before the current point 10s, and tension average value and change image (65) before the current point 100s, the LCD display The screen (6) is connected to the control module (2) through the second LCD display wiring pin (61) to dynamically display images, the X axis of the rectangular coordinate system (62) is the time change axis, and the rectangular coordinate system (62) The Y axis is the tension change axis, which dynamically displays the real-time tension value value and change image (63), the average tension value and change image (64) before the current point 10s, and the average tension value and change image (65) before the current point 100s , every time the image on one screen is displayed, the content of the previous screen will be covered and the current image will continue to be displayed.

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