CN108672964A - A kind of electric spark deposition built-up welding contact force automatic control device and autocontrol method - Google Patents

Abstract

An automatic contact force control device for electric spark deposition surfacing welding, comprising an actuator for driving an electrode head into contact with a substrate, an induction mechanism arranged between the actuator and the electrode head, electrically connected to the induction mechanism and controlled by the actuator The connected control mechanism; the executive mechanism includes a cross slide, and the plane where the cross slide is located is perpendicular to the substrate, and the drive of the cross slide is connected with an angle adjustment unit for clamping the electrode head; the sensing mechanism includes a fixed position on the cross slide and the angle The tension and pressure sensors between the adjustment units; the control mechanism includes a single-chip microcomputer, the single-chip microcomputer is electrically connected to the tension and pressure sensors, the single-chip microcomputer is connected to the cross slide control through the output drive interface, and the single-chip microcomputer is connected to the upper computer through the communication interface. The invention can automatically control the contact force between the moving electrode head and the fixed substrate in real time, and can also automatically compensate the deviation of the deposition position caused by the consumption of the electrode head.

Description

An automatic control device and automatic control method for electric spark deposition surfacing welding contact force

technical field

The invention relates to the technical field of electric spark deposition surfacing welding, in particular to an automatic control device and an automatic control method for electric spark deposition surfacing welding contact force.

Background technique

The working principle of EDM deposition welding technology is: when the electrode is in contact with the substrate, the circuit is in a short-circuit state, the power supply outputs a discharge pulse, and a large current density is generated in the small area of the contact point between the electrode and the substrate to make the contact point The electrode and the matrix material at the place melt and gasify instantly, triggering spark discharge, and the molten material of the electrode transitions to the surface of the matrix. If the electrode continues to approach the matrix, the matrix is extruded with mechanical force, so that the molten electrode material is firmly bonded to the matrix material. surface, the compactness of the alloy layer is improved. Since the discharge process of EDM surfacing is completed in an instant, the substrate will not produce thermal diffusion and thermal deformation, and has the advantages of small heat input and no heat generation of the substrate, so it is widely used in defects and small defects in molds, motor spindles and other equipment. In the precision repair of area damage, it can also be applied to the surface strengthening and modification of parts. The reuse of worn parts and other repairs belongs to regenerative manufacturing, which saves a lot of equipment maintenance costs.

The discharge voltage of EDM surfacing is low, and the generation of electric spark is mainly generated by contact discharge. Whether it is rotating electrode EDM surfacing or vibrating electrode EDM surfacing, it is necessary to contact the electrode with the substrate to generate electric spark discharge. In the process of EDM deposition welding, the electrode and the substrate need to be in constant contact. When the contact force is large, the contact area of the electrode and the substrate contact point increases, the current density decreases, and the micro-arc cannot be broken down. The generated electricity There are less sparks; when the contact force is small, the contact area between the electrode and the substrate contact point is small, the current density is high, and it is easy to generate a large electric spark, form a large arc crater, and cause a large splash; therefore, the electrode The size of the contact force with the substrate directly affects the form of spark discharge and the efficiency of quality transition, which in turn affects the quality of the deposited surfacing layer.

When the electrode is manually operated for EDM deposition welding, the contact force between the electrode and the substrate cannot be guaranteed, resulting in unstable spark discharge, and the quality of the deposited surfacing layer cannot be guaranteed, and the EDM deposition efficiency is low and the speed is slow. The operation time is long, and manual operation is easy to fatigue. Therefore, the use of automated EDM deposition welding system is an inevitable development direction. In the automatic operation of EDM surfacing, the electrode is operated by a manipulator or other mechanical mechanism, but the contact force between the electrode and the substrate needs to be automatically controlled separately, and there is no such technology and equipment at present. Usually, during EDM surfacing, the electrode axis is at a certain angle to the substrate plane, rather than perpendicular, so when the electrode becomes shorter due to consumption, the position of the contact point between the electrode and the substrate will also change. Compensation for this position change is also required.

In the prior art, there is still a lack of devices capable of automatically adjusting the magnitude of the contact force and the contact position.

Contents of the invention

In order to solve the deficiencies in the prior art, the present invention provides an automatic control device and automatic control method for the contact force of EDM surfacing, which can automatically control the contact force between the moving electrode tip and the fixed substrate in real time, and also Deviations in deposition position due to tip wear can be automatically compensated for.

In order to achieve the above purpose, the specific solution adopted by the present invention is: an automatic control device for electric spark deposition surfacing welding contact force, including an actuator used to drive the electrode tip to contact the substrate, and an actuator arranged between the actuator and the electrode tip. Induction mechanism, a control mechanism that is electrically connected to the induction mechanism and is connected to the actuator control; the actuator includes a cross slide, and the plane where the cross slide is located is perpendicular to the base, and the cross slide drive is connected to clamp the The angle adjustment unit of the electrode head; the induction mechanism includes a tension pressure sensor fixedly arranged between the cross slide and the angle adjustment unit; the control mechanism includes a single-chip microcomputer, and the single-chip microcomputer is electrically connected to the tension pressure sensor , the single-chip microcomputer is controlled and connected to the cross slide table through the output drive interface, and the single-chip microcomputer is connected to the upper computer through the communication interface.

The cross slide table includes a horizontal adjustment unit and a vertical adjustment unit, the horizontal adjustment unit and the vertical adjustment unit are respectively provided with a fixed base plate, and a stepping motor and two parallel light bar guide rails are fixedly arranged on the fixed base plate, and the stepping motor The output shaft is coaxially connected with a ball screw. The ball screw is located between the two light rod guide rails and is parallel to the light rod guide rails. The ball screw is fitted with a slide table, and the slide table and the light rod guide rail slide connection, the fixed bottom plate of the vertical adjustment unit is fixedly connected with the slide table of the horizontal adjustment unit, the tension pressure sensor is fixedly connected with the slide table of the vertical adjustment unit; each of the two stepper motors is connected to the output drive interface through a driver electrical connection.

The sliding table of the vertical adjustment unit is fixedly connected with an L-shaped plate, the L-shaped plate includes a vertical part and a horizontal part integrally connected, a reinforcing rib is also arranged between the vertical part and the horizontal part, and the vertical part and the sliding part of the vertical adjustment unit The table is fixedly connected, the horizontal part is fixedly connected with a connecting plate, and the tension pressure sensor is fixedly connected with the connecting plate.

The angle adjustment unit includes a U-shaped plate and a T-shaped connecting cylinder, wherein the U-shaped plate is fixedly connected with the tension pressure sensor, and the T-shaped connecting cylinder is composed of an integrally connected installation cylinder and a connecting cylinder, and the connecting cylinder is rotatably arranged on the U-shaped Between the two side walls of the plate, the electrode head is fixedly arranged on the installation cylinder.

A welding torch is fixedly pierced in the installation cylinder, and the electrode head is fixedly arranged on the welding torch.

Two end plates are also fixedly arranged on the fixed base plate, the two end plates are parallel to each other and perpendicular to the fixed base plate, the two light bar guide rails are fixedly arranged between the two end plates, and the ball wires The bar passes through the two end plates in turn, and a limit switch is fixedly arranged on each of the two end plates, and the two limit switches are arranged oppositely.

The single-chip microcomputer is also electrically connected with a keyboard and a display screen.

The single chip microcomputer is electrically connected with the tension pressure sensor through a signal conditioning circuit and a transmitter in turn.

The above-mentioned automatic control method of an electric discharge deposition welding contact force automatic control device includes the following steps:

Step 1. The cross slide pushes the electrode head down to make contact with the substrate;

Step 2, the pull pressure sensor detects the contact force between the substrate and the electrode tip, and transmits the contact force data to the single-chip microcomputer;

Step 3, the single-chip microcomputer compares the contact force data with the set value, if the contact force data is greater than the set value, then perform step 4, if the contact force data is less than the set value, then perform step 5, if the contact force data is equal to the set value value, no action will be performed, and step 3 will be performed again;

Step 4. The single-chip microcomputer controls the cross slide to push the electrode head upwards, and then proceed to step 6;

Step 5. The single-chip microcomputer controls the cross slide to push the electrode head down, and then proceed to step 7;

Step 6. The single-chip microcomputer calculates the compensation distance in the horizontal direction through the upward moving distance of the electrode head, and then controls the cross slide to push the electrode head to move horizontally, and then execute step 3 again;

Step 7. The single-chip microcomputer calculates the compensation distance in the horizontal direction based on the downward movement distance of the electrode head, and then controls the cross slide to push the electrode head to move horizontally, and then executes step 3 again.

Beneficial effects: the present invention can automatically control the contact force between the moving electrode head and the fixed substrate in real time, and can also automatically compensate the deviation of the deposition position due to the consumption of the electrode head, thus ensuring the contact force between the electrode head and the substrate. The accuracy of the contact position between them ensures the stable output of the electric spark, the stability of the deposition surface quality and the uniform thickness of the deposition layer in the automatic process of EDM deposition welding.

Description of drawings

Fig. 1 is the overall structural representation of automatic control device of the present invention;

Fig. 2 is the structural representation of actuator and induction structure of the present invention;

Fig. 3 is the structural block diagram of control mechanism of the present invention;

Fig. 4 is a schematic diagram of the principle of the contact position compensation process of the present invention.

Reference signs: 1-stepping motor, 2-coupling, 3-limit switch, 4-light rod guide rail, 5-ball screw, 6-sliding table, 7-reinforcing rib, 8-L-shaped plate, 9-connecting plate, 10-fixed bottom plate, 11-pull pressure sensor, 12-U-shaped plate, 13-T-shaped connecting cylinder, 14-welding torch, 15-electrode head, 16-substrate, 17-end plate.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Please refer to Figures 1 to 3, Figure 1 is a schematic diagram of the overall structure of the automatic control device of the present invention, Figure 2 is a schematic structural diagram of the actuator and the induction structure of the present invention, and Figure 3 is a structural block diagram of the control mechanism of the present invention.

An automatic contact force control device for electrospark deposition surfacing welding, including an actuator for driving the electrode head 15 into contact with the substrate 16, an induction mechanism arranged between the actuator and the electrode head 15, electrically connected to the induction mechanism and connected to the The actuator controls the connected control mechanism. The sensing mechanism is used to sense the contact force between the electrode head 15 and the substrate 16, the control structure is used to obtain the contact force from the sensing mechanism and control the movement of the actuator according to the contact force, and the actuator is used to move under the control of the control mechanism In order to change the contact force and contact position between the electrode tip 15 and the substrate 16 .

The actuator includes a cross slide, and the plane where the cross slide is located is perpendicular to the substrate 16. The cross slide is driven and connected with an angle adjustment unit for clamping the electrode head 15, and the angle adjustment unit is used for the gap between the electrode head 15 and the base 16. to adjust the included angle.

The sensing mechanism includes a tension and pressure sensor 11 fixedly arranged between the cross slide and the angle adjustment unit. The tension and pressure sensor 11 is a tension and pressure sensor of model AT8202, and the measuring range is 20N.

The control mechanism includes a single-chip microcomputer. The single-chip microcomputer is selected from the ADuC824 single-chip microcomputer. The single-chip microcomputer is electrically connected to the tension and pressure sensor 11. The single-chip microcomputer is connected to the cross slide control through the output drive interface. The single-chip microcomputer is connected to the host computer through the communication interface.

During the EDM surfacing process, the contact force generated by the contact between the electrode head 15 driven by the cross slide and the substrate 16 can be collected by the pull pressure sensor 11. After the contact force is transmitted to the single-chip microcomputer, the single-chip microcomputer can analyze the contact force . If the current contact force is too large, the single-chip microcomputer can drive the electrode tip 15 to move away from the substrate 16 by controlling the cross slide, thereby reducing the contact force; if the current contact force is too small, the single-chip microcomputer can drive the electrode tip by controlling the cross slide 15 moves toward the substrate 16, thereby increasing the contact force; if the current contact force is appropriate, then EDM surfacing can be performed normally. The single-chip microcomputer can also transmit the contact force and the control data of the cross slide to the host computer through the communication interface for relevant personnel to view, and the relevant personnel can also transmit control instructions to the single-chip microcomputer through the host computer, and then realize the control of the cross slide. Adjust manually.

Please refer to FIG. 4 , which is a schematic diagram of the principle of the contact position compensation process of the present invention. During the surfacing process of EDM, the electrode tip 15 will be worn out, resulting in the continuous decrease of the contact force between the electrode tip 15 and the substrate 16. Therefore, it is necessary to continuously move the electrode tip 15 to the direction of the substrate 16, and because the electrode tip 15 and the substrate 16 have an included angle, so the movement of the electrode tip 15 will cause the contact position between the electrode tip 15 and the substrate 16 to change. When the electrode has a Δz displacement along the vertical direction, the contact point between the electrode and the substrate is in the horizontal direction There will be an offset of Δx , and the single-chip microcomputer can calculate Δx according to the angle between the electrode head 15 and the substrate 16 and Δz , and then control the movement of the electrode head 15 by controlling the cross slide to realize the compensation for the change of the contact position. This ensures that the contact position between the electrode tip 15 and the substrate 16 can be kept stable, thereby ensuring the stability of the entire surfacing process.

In summary, the present invention can automatically control the contact force between the moving electrode head 15 and the fixed substrate 16 in real time, and can also automatically compensate the deviation of the deposition position due to the consumption of the electrode head 15, thereby ensuring The accurate contact position between the electrode head 15 and the base body 16 further ensures the stable output of electric sparks, the stable quality of the deposited surface and the uniform thickness of the deposited layer during the automatic process of EDM deposition welding.

In the case where the substrate 16 is installed horizontally, the magnitude of the contact force is achieved by moving the electrode head 15 close to or away from the substrate 16, and the compensation for the contact position is realized by moving the electrode head 15 to move along the substrate 16, so the cross slide It is only necessary to control the movement of the electrode head 15 in the vertical direction and the horizontal direction. The cross slide table is set to include a horizontal adjustment unit and a vertical adjustment unit. The horizontal adjustment unit and the vertical adjustment unit are respectively provided with a fixed base plate 10. A stepping motor 1 and two parallel light rod guide rails 4 are fixedly installed. The output shaft of the stepping motor 1 is coaxially connected with a ball screw 5 through a coupling 2, and the ball screw 5 is located on the two light rod guide rails. 4 and parallel to the light bar guide rail 4, the ball screw 5 is fitted with a slide table 6, and the slide table 6 is slidably connected with the light bar guide rail 4, the fixed bottom plate 10 of the vertical adjustment unit is connected with the sliding table of the horizontal adjustment unit The table 6 is fixedly connected, and the pull pressure sensor 11 is fixedly connected with the sliding table 6 of the vertical adjustment unit; each of the two stepper motors 1 is electrically connected to the output drive interface through a driver, and the output drive interface is selected as an optocoupler isolation drive circuit. When adjusting the contact force between the electrode tip 15 and the base body 16, the single-chip microcomputer drives the stepper motor 1 of the vertical adjustment unit to run, and the stepper motor 1 drives the ball screw 5 of the vertical adjustment unit to rotate, thereby driving the sliding of the vertical adjustment unit. The stage 6 moves in the vertical direction, and the light bar guide rail 4 is used to limit the direction of the sliding stage 6, and finally the electrode head 15 is driven close to or away from the base body 16 through the tension pressure sensor 11 and the angle adjustment unit in turn; When the contact position between them is reached, the stepper motor 1 of the horizontal adjustment unit runs, thereby driving the ball screw 5 of the horizontal adjustment unit to rotate, and then pushing the sliding table 6 of the horizontal adjustment unit to move and driving the vertical adjustment unit to move as a whole, and finally through the vertical adjustment unit. The adjustment unit drives the electrode head 15 to move along the base body 16 . The present invention decomposes the adjustment process of the electrode head 15 into vertical and horizontal position adjustment processes, thereby reducing the complexity of the automatic control device and the automatic control process. In other embodiments of the present invention, the combination of the stepper motor 1 and the ball screw 5 can also be replaced by other linear output devices, such as air cylinders or hydraulic cylinders.

The specific connection mode between the tension pressure sensor 11 and the vertical adjustment unit is: the slide table 6 of the vertical adjustment unit is fixedly connected with an L-shaped plate 8, in order to facilitate the connection between the L-shaped plate 8 and the slide table 6, the light rod guide rail 4, the ball wire The three components of the bar 5 and the sliding table 6 can be directly selected from the KKM60 linear module. The L-shaped plate 8 includes a vertical part and a horizontal part integrally connected, and a reinforcing rib 7 is arranged between the vertical part and the horizontal part. The reinforcing rib 7 increases the support rigidity and strength of the L-shaped plate 8 to ensure stable operation. The vertical part is fixedly connected with the slide table 6 of the vertical adjustment unit, the horizontal part is fixedly connected with the connecting plate 9 , and the tension pressure sensor 11 is fixedly connected with the connecting plate 9 .

The angle adjustment unit includes a U-shaped plate 12 and a T-shaped connecting cylinder 13, wherein the U-shaped plate 12 is fixedly connected with the tension pressure sensor 11, and the T-shaped connecting cylinder 13 is composed of an integrally connected installation cylinder and a connecting cylinder. Between the two side walls of the pattern plate 12 , a welding torch 14 is fixedly pierced in the installation cylinder, and the electrode head 15 is fixedly arranged on the welding torch 14 . Before performing the surfacing operation, the angle between the electrode tip 15 and the substrate 16 can be adjusted by rotating the welding torch 14 to drive the electrode tip 16 to meet the needs of different surfacing welding conditions.

Two end plates 17 are also fixedly arranged on the fixed base plate 10, and the two end plates 17 are parallel to each other and are all perpendicular to the fixed base plate 10. The two light bar guide rails 4 are fixedly arranged between the two end plates 17, and the ball wire The bar 5 passes through two end plates 17 in turn, and a limit switch 3 is fixedly arranged on each of the two end plates 17, and the two limit switches 3 are arranged oppositely, when the distance between the slide table 6 and the limit switch 3 When the shrinkage reaches a certain level, the limit switch 3 is triggered, and the stepper motor 1 automatically stops running, thereby avoiding the situation that the horizontal adjustment unit and the vertical adjustment unit are damaged due to excessive adjustment during the adjustment process.

The single-chip microcomputer is also electrically connected with a keyboard and a display screen. Among them, the keyboard is used to input the set value of the contact force to the single-chip microcomputer. The single-chip microcomputer can compare with the set value when judging the current contact force. The keyboard can also be used to manually control the start and stop. The keyboard can use a matrix keyboard, and It is connected with the ADuC824 MCU through the P2 port; the display screen is used to display the current contact force data and other state parameters in the surfacing process. The ADuC824 microcontroller is connected for the operator to check.

The single chip microcomputer is electrically connected with the pull pressure sensor through the signal conditioning circuit and the transmitter in turn. The transmitter converts the physical quantity measured by the pull pressure sensor 11 into a 4-20mA electrical signal and outputs it to the signal conditioning circuit; the signal conditioning circuit converts the received electrical signal into a 1-5V voltage signal, and then connects it to the The analog quantity input interface AIN1 of ADuC824 single-chip microcomputer, ADuC824 single-chip microcomputer carries on AD sampling again, finally obtains the digital quantity of contact force.

Based on the above-mentioned automatic control device, the present invention also provides an automatic control method of an automatic control device for contact force in electro-spark deposition surfacing welding, including steps 1 to 7.

Step 1. The cross slide pushes the electrode head 15 to move down to contact with the substrate 16 .

Step 2. The pull pressure sensor 11 detects the contact force between the substrate 16 and the electrode tip 15, and transmits the contact force data to the single-chip microcomputer.

Step 3. The MCU compares the contact force data with the set value. If the contact force data is greater than the set value, perform step 4. If the contact force data is less than the set value, perform step 5. If the contact force data is equal to the set value, then If there is no action, go to step 3 again.

Step 4, the single-chip microcomputer controls the cross slide to push the electrode head 15 to move upward, and then proceed to step 6.

Step 5, the single-chip microcomputer controls the cross slide to push the electrode head 15 to move downward, and then proceed to step 7.

Step 6. The single-chip microcomputer calculates the compensation distance in the horizontal direction according to the upward movement distance of the electrode head 15, and then controls the cross slide to push the electrode head 15 to move horizontally, and then executes step 3 again.

Step 7. The single-chip microcomputer calculates the compensation distance in the horizontal direction according to the downward movement distance of the electrode head 15, and then controls the cross slide to push the electrode head 15 to move horizontally, and then executes step 3 again.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (9)

1. An automatic contact force control device for electrospark deposition welding, characterized in that: it includes an actuator for driving the electrode tip (15) to contact the substrate (16), and is arranged between the actuator and the electrode tip (15). The induction mechanism between them, the control mechanism that is electrically connected with the induction mechanism and is connected with the control mechanism of the actuator; The actuator includes a cross slide, and the plane where the cross slide is located is perpendicular to the base (16), and the cross slide is driven and connected with an angle adjustment unit for clamping the electrode head (15); The sensing mechanism includes a tension and pressure sensor (11) fixedly arranged between the cross slide and the angle adjustment unit; The control mechanism includes a single-chip microcomputer, the single-chip microcomputer is electrically connected to the tension and pressure sensor (11), the single-chip microcomputer is connected to the cross slide through an output drive interface, and the single-chip microcomputer is connected to a host computer through a communication interface. 2. The automatic contact force control device for electro-spark deposition surfacing welding according to claim 1, characterized in that: the cross slide table includes a horizontal adjustment unit and a vertical adjustment unit, and the horizontal adjustment unit and the vertical adjustment unit are respectively equipped with The fixed bottom plate (10) is fixed with a stepping motor (1) and two parallel light bar guide rails (4) on the fixed bottom plate (10), and the output shaft of the stepping motor (1) is coaxially fixed with balls The lead screw (5), the ball screw (5) is located between the two light rod guide rails (4) and parallel to the light rod guide rails (4), and the ball screw (5) is fitted with a slide table (6) , and the sliding table (6) is slidingly connected with the light bar guide rail (4), the fixed bottom plate (10) of the vertical adjustment unit is fixedly connected with the sliding table (6) of the horizontal adjustment unit, and the tension pressure sensor (11) is connected with the vertical adjustment unit The sliding table (6) of the unit is fixedly connected; Each of the two stepping motors (1) is electrically connected to the output drive interface through a driver. 3. An automatic contact force control device for EDM surfacing welding according to claim 2, characterized in that: an L-shaped plate (8) is fixedly connected to the sliding table (6) of the vertical adjustment unit, and the L-shaped The plate (8) includes a vertical part and a horizontal part integrally connected, and a reinforcing rib (7) is arranged between the vertical part and the horizontal part, the vertical part is fixedly connected with the slide table (6) of the vertical adjustment unit, and the horizontal part is fixedly connected with A connection plate (9), the tension pressure sensor (11) is fixedly connected with the connection plate (9). 4. An automatic contact force control device for EDM surfacing welding according to claim 3, characterized in that: the angle adjustment unit includes a U-shaped plate (12) and a T-shaped connecting cylinder (13), wherein the U-shaped The plate (12) is fixedly connected with the tension pressure sensor (11), and the T-shaped connecting cylinder (13) is composed of an integrally connected installation cylinder and a connecting cylinder, and the connecting cylinder is rotatably arranged between the two side walls of the U-shaped plate (12). Between, the electrode head (15) is fixedly arranged on the installation cylinder. 5. An automatic contact force control device for EDM surfacing welding according to claim 4, characterized in that: a welding torch (14) is fixedly pierced in the installation cylinder, and the electrode head (15) is fixedly arranged on on the welding torch (14). 6. An automatic contact force control device for EDM surfacing welding according to claim 2, characterized in that two end plates (17) are fixedly arranged on the fixed bottom plate (10), and the two end plates (17) are parallel to each other and perpendicular to the fixed bottom plate (10), the two light rod guide rails (4) are fixedly arranged between the two end plates (17), and the ball screws (5) pass through in turn Through the two end plates (17), a limit switch (3) is fixedly arranged on each of the two end plates (17), and the two limit switches (3) are arranged oppositely. 7. An automatic contact force control device for electro-spark deposition surfacing welding according to claim 1, characterized in that: the single-chip microcomputer is also electrically connected with a keyboard and a display screen. 8 . The automatic contact force control device of EDM surfacing welding according to claim 1 , wherein the single-chip microcomputer is electrically connected to the tension and pressure sensor through a signal conditioning circuit and a transmitter in sequence. 9. The automatic control method of a kind of electric spark deposition welding contact force automatic control device as claimed in claim 1, it is characterized in that: comprise the following steps: Step 1. The cross slide pushes the electrode head (15) to move down to contact with the substrate (16); Step 2. The pull pressure sensor (11) detects the contact force between the substrate (16) and the electrode head (15), and transmits the contact force data to the single-chip microcomputer; Step 3, the single-chip microcomputer compares the contact force data with the set value, if the contact force data is greater than the set value, then perform step 4, if the contact force data is less than the set value, then perform step 5, if the contact force data is equal to the set value value, no action will be performed, and step 3 will be performed again; Step 4. The single-chip microcomputer controls the cross slide to push the electrode head (15) to move upward, and then proceed to step 6; Step 5, the single-chip microcomputer controls the cross slide to push the electrode head (15) to move downward, and then proceed to step 7; Step 6. The single-chip microcomputer calculates the compensation distance in the horizontal direction through the upward movement distance of the electrode head (15), and then controls the cross slide to push the electrode head (15) to move horizontally, and then execute step 3 again; Step 7. The single-chip microcomputer calculates the compensation distance in the horizontal direction based on the downward movement distance of the electrode head (15), and then controls the cross slide to push the electrode head (15) to move horizontally, and executes step 3 again.