CN115754685A

CN115754685A - PCBA test pre-electrifying jig

Info

Publication number: CN115754685A
Application number: CN202310023957.7A
Authority: CN
Inventors: 黄春生; 杜其亮; 周猛; 付文兵; 袁鹏
Original assignee: Microgrid Union Technology Chengdu Co ltd
Current assignee: Microgrid Union Technology Chengdu Co ltd
Priority date: 2023-01-09
Filing date: 2023-01-09
Publication date: 2023-03-07

Abstract

The invention discloses a pre-electrifying jig for PCBA (printed circuit board assembly) test, which belongs to the field of jigs, wherein an air bag and an elastic resetting piece are compressed by the downward pressure of a manipulator and the PCBA, liquid in the air bag is extruded into an air duct, the liquid can push a sliding plug to move left, magnetofluid in a hydraulic pipeline is pushed to the upper part of an upper clamping plate, the gravity center of the upper clamping plate is raised, the elastic resetting piece is bent and drives the upper clamping plate to press down, the sliding plug can pull a sliding block to move left while moving left, a magnetic separation plate is pulled into the duct to expose a magnetic strip, a downward magnetic conduction plate is attracted with the magnetic strip, the clamping force of the upper clamping plate is effectively improved, after the PCBA is taken out by the manipulator, the upper clamping plate is lifted, the upper clamping plate is reset by the elastic resetting piece, the air bag is restored to the original state, the sliding plug moves right to push the magnetic separation plate out to cover the upper part of the magnetic strip, the magnetic separation plate is isolated from the magnetic property, and the magnetofluid flows back into the hydraulic pipeline again to keep a certain opening and closing angle of the upper clamping plate and the lower clamping plate.

Description

PCBA test pre-electrifying jig

Technical Field

The invention relates to the field of jigs, in particular to a PCBA test pre-electrifying jig.

Background

PCBA test fixture is very important equipment in the PCBA processing factory, generally places in the end of production link, is used for detecting whether the product is intact, when carrying out PCBA test fixture preparation and test, need accord with the requirement of regulation and just can improve the rate of accuracy of test, improve shipment quality, PCBA test fixture is the tool of testing, experimenting function, power calibration, life-span, performance etc. of product specially, it is mainly used for the test of each item index of product on the PCBA production line.

PCBA adopts the manipulator centre gripping to place PCBA on the workstation of difference usually in the course of working, utilizes the holder centre gripping fixed afterwards, however PCBA before placing, needs the manipulator to lift up the grip block in advance, and operating procedure is complicated, need lift up the grip block again when taking out PCBA equally, consequently, PCBA all needs the manipulator to relapse the lifting action of carrying out when placing and taking out, has so not only reduced work efficiency, also is not convenient for PCBA's stable centre gripping.

Therefore, the PCBA test pre-electrifying jig is provided to solve the problems that the clamping process is complex and the clamping force is insufficient.

Disclosure of Invention

1. Technical problem to be solved

Aiming at the problems in the prior art, the invention aims to provide a PCBA test pre-electrifying jig, a gas bag and an elastic resetting piece are compressed by the aid of downward pressure of a manipulator and the PCBA, liquid in the gas bag is extruded into an air duct, the liquid can push a sliding plug to move left, then magnetic fluid in a hydraulic pipeline is pushed to the upper portion of an upper clamping plate to lift the gravity center of the upper clamping plate, the elastic resetting piece is bent and drives the upper clamping plate to press downwards, the PCBA is pressed down by the sliding plug while moving left, a pull rope can pull a sliding block to move left to pull a magnetic separation plate into the channel to expose a magnetic strip, the pressed magnetic separation plate is attracted to the magnetic strip, clamping force of the upper clamping plate is effectively improved, the PCBA is prevented from being translocated and poorly contacted due to unstable clamping, after machining is completed, the manipulator takes out the PCBA and lifts the upper clamping plate, the upper clamping plate is reset by the elastic resetting piece, the gas bag is restored to the original state, the sliding plug is pushed out to cover the magnetic strip of the magnetic separation plate, magnetism is isolated, and meanwhile, the PCBA flows back into the interior of the pipeline again to keep the upper clamping plate and the lower clamping plate open and close at a certain angle.

2. Technical scheme

A PCBA test pre-electrifying jig comprises a jig body, wherein positioning holes are formed in four corners of the jig body, a battery box is mounted on the jig body, an electric quantity display screen is arranged at one end of the battery box, a machining panel is mounted on the jig body, guide blocks are fixedly connected to the four corners of the machining panel, a charging probe is mounted below each guide block, a plurality of round holes are formed in the machining panel, and a plurality of clamping components are fixedly mounted at the upper end and the lower end of the machining panel;

the clamping assembly comprises an upper clamping plate and a lower clamping plate, the upper clamping plate and the lower clamping plate are rotatably connected through a rotating shaft, a plurality of elastic reset pieces are fixedly connected between the upper clamping plate and the lower clamping plate, a plurality of groups of hydraulic pipelines are arranged on the inner walls of the upper clamping plate and the lower clamping plate, the hydraulic pipelines of the same group are communicated through a communicating hose, a groove communicated with the hydraulic pipelines is arranged on the side wall of the upper end of the lower clamping plate, which is far away from the upper clamping plate, the bottom of the groove is fixedly connected with a magnetic strip, a magnetic isolation plate is slidably connected on the inner wall of the hydraulic pipeline, which is close to the groove, a sliding block is slidably connected on the inner wall of the hydraulic pipeline, which is close to the magnetic isolation plate, a guide rod is fixedly connected between the sliding block and the magnetic isolation plate, a fixed block is fixedly connected on the inner wall of the hydraulic pipeline, which is close to the sliding block, the fixed block is connected with the sliding block through a spring, and a sliding plug is also slidably connected on the inner wall of the hydraulic pipeline, which is positioned in the lower clamping plate, magnetic fluid is filled in a space between a hydraulic pipeline and a sliding plug in an upper clamping plate, a pull rope is fixedly connected to the side wall of the sliding block, the pull rope penetrates through a fixing block and is fixedly connected with the sliding plug, a plurality of air bags are fixedly connected to the side wall of the upper end of a lower clamping plate, liquid is filled in the air bags, an air passage is communicated between the air bags and the hydraulic pipeline, the air bags and an elastic resetting piece are compressed through the downward pressure of a manipulator and a PCBA (printed Circuit Board Assembly), the liquid in the air bags is extruded into the air passage, the liquid can push the sliding plug to move to the left, the magnetic fluid in the hydraulic pipeline is further pushed to the upper clamping plate to raise the gravity center of the upper clamping plate, the elastic resetting piece is bent and drives the upper clamping plate to press downwards, the PCBA is pressed, the sliding plug can pull the sliding block to move to the left while moving to pull the magnetic separation plate into a passage to expose the magnetic strips, and the magnetic conduction plates and the magnetic strips pressed downwards, effectively improved the clamp force of punch holder, prevent that the PCBA board from because of the centre gripping is unstable, the emergence is translocated and the condition of contact failure, processing is accomplished the back, can lift up the punch holder when the manipulator takes out the PCBA board, reset the punch holder through elasticity, gasbag reconversion, sliding plug moves to the right and pushes out the magnetic separator, the cover is in the top of magnetic stripe, isolated magnetism, simultaneously, the magnetic fluid flows back into hydraulic duct inside again, make punch holder and lower plate keep certain angle that opens and shuts.

Further, elasticity piece that resets includes hollow cylinder, and the inner wall fixedly connected with rubber stick of hollow cylinder, and hollow cylinder is the ripple shape, and hollow cylinder adopts rubber materials, and the rubber stick adopts flexible elastic material, and elastic rubber stick can lift up the punch holder, realizes the function that resets fast.

Further, the gasbag is the oval-shaped, and the last fixed surface of gasbag is connected with the silica gel pad, and the silica gel pad protects the gasbag upper surface, prevents the condition that the gasbag wearing and tearing break away in the clamping process.

Furthermore, the quantity that elasticity resets is two, and two elasticity resets the both sides that the piece symmetric distribution was at punch holder and lower plate, and the elasticity that distributes in both sides resets the piece and has sufficient power to reset and support the punch holder.

Furthermore, the side wall of the upper end of the upper clamping plate is fixedly embedded with a magnetic conduction plate, the magnetic conduction plate is close to the upper end of the hydraulic pipeline, and the magnetic conduction plate has an attraction effect on magnetic fluid in the hydraulic pipeline, so that the gravity center of the upper clamping plate is changed, and the clamping effect is achieved.

Furthermore, the rotation angle of the upper clamping plate is 70-90 degrees, a balancing weight is fixedly embedded in the inner wall of the upper end of the upper clamping plate, the clamping force of the upper clamping plate can be increased by the balancing weight, and the situation that clamping is not loosened and misplaced is prevented.

Further, the area of magnetism proof board is greater than the area of magnetic stripe, and magnetism proof board adopts hollow structure, and magnetism proof board can be with the complete cover of magnetic stripe to effectively isolated magnetism can not influence the lifting of punch holder.

Further, elasticity resets and the gasbag is on same straight line, and the lower extreme that elasticity resets keeps away from the vertical line at the top place of punch holder for PCBA can be accurate pushes down on the gasbag, and elasticity resets and carries out certain collision avoidance to PCBA's front end.

3. Advantageous effects

Compared with the prior art, the invention has the advantages that:

(1) The down pressure through manipulator and PCBA can compress gasbag and elasticity piece that resets, extrude inside liquid of gasbag inside to the air channel inside, liquid can promote the sliding plug and move to the left side, and then promote the inside magnetic current body of hydraulic duct to the punch holder top, in order to raise the focus of punch holder, elasticity piece that resets is bent and is taken the punch holder and push down simultaneously, thereby push down PCBA, the sliding plug can pull the sliding block and move to the left side when moving to the left side, draw the magnetic shield into the passageway, make the magnetic stripe expose, the magnetic shield that pushes down attracts with the magnetic stripe, the clamp force of punch holder has effectively been improved, prevent PCBA board because of the centre gripping unstability, take place translocation and the bad condition of contact, after the processing is accomplished, the manipulator can lift the punch holder when taking out the PCBA board, reset the punch holder through elasticity piece, the gasbag resumes the original state, the sliding plug moves to the right and pushes out the magnetic shield, cover in the top of magnetic stripe, the isolated magnetism, simultaneously, the magnetic current body flows back into hydraulic duct again, make punch holder and lower plate keep certain angle that opens and shuts.

(2) Elasticity piece that resets includes hollow cylinder, and the inner wall fixedly connected with rubber stick of hollow cylinder, hollow cylinder is the ripple shape, and hollow cylinder adopts rubber materials, and the rubber stick adopts flexible elastic material, and elastic rubber stick can lift up the punch holder, realizes the function that resets fast, and simultaneously, built-in rubber stick can also improve the toughness that elasticity reset the piece.

(3) The gasbag is the ellipsoid shape, and the last fixed surface of gasbag is connected with the silica gel pad, and the gasbag of ellipsoid shape can be quick pushes down the resilience, and the silica gel pad protects the gasbag upper surface, prevents the condition that gasbag wearing and tearing break away in the clamping process.

(4) Elasticity resets the quantity of piece and is two, and two elasticity resets the both sides that the piece symmetric distribution resets at punch holder and lower plate, and the elasticity that distributes in both sides resets has sufficient power to reset and support the punch holder, and PCBA pushes down when elasticity resets on the piece, also can take place the bending fast, makes the punch holder push down.

(5) The side wall of the upper end of the upper clamping plate is fixedly embedded with a magnetic conduction plate, the magnetic conduction plate is close to the upper end of the hydraulic pipeline, and the magnetic conduction plate has an attraction effect on magnetic fluid in the hydraulic pipeline, so that the gravity center of the upper clamping plate is changed, and the clamping effect is achieved.

(6) The turned angle of the upper clamping plate is 70-90 degrees, the inner wall of the upper end of the upper clamping plate is fixedly embedded with a balancing weight, and the balancing weight can increase the clamping force of the upper clamping plate, so that the situation of clamping loosening and dislocation is prevented.

(7) The area of magnetic shield is greater than the area of magnetic stripe, and the magnetic shield adopts hollow structure, and the magnetic shield can be with the complete cover of magnetic stripe to effectively isolated magnetism can not influence the lifting of punch holder.

(8) Elasticity resets and the gasbag is on same straight line, and the lower extreme that elasticity resets keeps away from the vertical line at the top place of punch holder for PCBA can be accurate push down on gasbag and elasticity reset, and elasticity resets and carries out certain anticollision protection to PCBA's front end.

Drawings

FIG. 1 is a view showing a variation of the operation of the clamping assembly of the present invention;

fig. 2 is a top view of the pre-charging jig of the present invention;

FIG. 3 is a block diagram of the clamping assembly of FIG. 2;

FIG. 4 is a side view of the clamping assembly of FIG. 3;

FIG. 5 is a schematic view of the rebound state of the air bag;

FIG. 6 is a schematic view showing a state in which the air bag is pressed down;

FIG. 7 is a top clamping plate elevation working view;

FIG. 8 is a schematic structural view of an elastic restoring member;

fig. 9 is a cross-sectional view of the resilient return member of fig. 8.

The reference numbers in the figures illustrate:

1. a jig body; 2. positioning holes; 3. a battery case; 4. an electric quantity display screen; 5. processing a panel; 6. a guide block; 7. charging the probe; 8. a circular hole; 9. a clamping assembly; 901. an upper splint; 902. a rotating shaft; 903. a lower splint; 904. a magnetic conductive plate; 905. an elastic reset member; 906. an air bag; 907. a groove; 908. a magnetic strip; 909. a magnetic shield plate; 910. a guide bar; 911. a slider; 912. pulling a rope; 913. a fixed block; 914. a hydraulic conduit; 915. a sliding plug; 916. an air duct; 917. a rubber rod.

Detailed Description

The technical solutions in the embodiments of the present application will be described below clearly and completely with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments, and all other embodiments obtained by a person of ordinary skill in the art without making creative efforts based on the embodiments in the present application belong to the protection scope of the present application.

Example 1:

the invention provides a PCBA test pre-electrifying jig, please refer to fig. 2, which comprises a jig body 1, wherein positioning holes 2 are formed in four corners of the jig body 1, a battery box 3 is arranged on the jig body 1, an electric quantity display screen 4 is arranged at one end of the battery box 3, a processing panel 5 is arranged on the jig body 1, guide blocks 6 are fixedly connected to the four corners of the processing panel 5, charging probes 7 are arranged below the guide blocks 6, a plurality of round holes 8 are formed in the processing panel 5, and a plurality of clamping components 9 are fixedly arranged at the upper end and the lower end of the processing panel 5;

referring to fig. 3, 4, 8 and 9, the clamping assembly 9 includes an upper clamping plate 901 and a lower clamping plate 903, the upper clamping plate 901 and the lower clamping plate 903 are rotatably connected through a rotating shaft 902, a plurality of elastic reset pieces 905 are fixedly connected between the upper clamping plate 901 and the lower clamping plate 903, the number of the elastic reset pieces 905 is two, the two elastic reset pieces 905 are symmetrically distributed on two sides of the upper clamping plate 901 and the lower clamping plate 903, the elastic reset pieces 905 distributed on the two sides have enough force to reset and support the upper clamping plate 901, each elastic reset piece 905 includes a hollow cylinder, a rubber rod 917 is fixedly connected to the inner wall of the hollow cylinder, the hollow cylinder is corrugated, the hollow cylinder is made of rubber material, the rubber rod 917 is made of flexible elastic material, and the elastic rubber rod 917 can lift the upper clamping plate 901 to realize a quick reset function;

referring to fig. 5-7, the rotation angle of the upper clamp 901 is 70-90 °, and a balancing weight is fixedly embedded in the inner wall of the upper end of the upper clamp 901, the balancing weight can increase the clamping force of the upper clamp 901, thereby preventing the clamping from loosening and dislocation, the inner walls of the upper clamp 901 and the lower clamp 903 are both provided with a plurality of sets of hydraulic pipes 914, and the same set of hydraulic pipes 914 are communicated through a communication hose, the upper side wall of the upper clamp 901 is fixedly embedded with a magnetic conductive plate 904, and the magnetic conductive plate 904 is close to the upper end of the hydraulic pipe 914, the magnetic conductive plate 904 has an attraction effect on the magnetic fluid in the hydraulic pipe 914, thereby changing the center of gravity of the upper clamp 901, achieving the clamping effect, the upper side wall of the lower clamp 903 far from the upper clamp 901 is provided with a groove 907 communicating with the hydraulic pipe 914, and the bottom of the groove 915 is fixedly connected with a magnetic isolation 908, the inner wall of the hydraulic pipe 914 close to the groove 907 is slidably connected with a magnetic isolation plate 909, the area of the magnetic isolation plate 909 is larger than the area of the magnetic isolation plate 908, and the magnetic isolation plate 909 is larger than the area of the magnetic isolation plate 909, and the sliding block 913, and the sliding block 914 is connected with a sliding block 911, the sliding block 911 connected between the sliding block 914 connected with a sliding block 911 connected in the sliding block 911, a plurality of gasbags 906 of the upper end lateral wall fixedly connected with of lower plate 903, gasbag 906 is the oval ball shape, and the last fixed surface of gasbag 906 is connected with the silica gel pad, the silica gel pad is protected the gasbag upper surface, prevent the condition that gasbag 906 wearing and tearing break down in the centre gripping process from appearing, and be filled with liquid in the gasbag 906, the intercommunication has air vent 916 between gasbag 906 and the hydraulic pressure pipeline 914, elasticity resets 905 and gasbag 906 on same straight line, and the lower extreme of elasticity resets 905 keeps away from the vertical line at the top place of upper plate 901, make PCBA can be accurate push down on gasbag 906, elasticity resets 905 and carries out certain collision avoidance to PCBA's front end.

When the manipulator places the PCBA plate on the lower clamp 903, the downward pressure of the manipulator and the PCBA compresses the air bag 906 and the elastic resetting piece 905, liquid in the air bag 906 is extruded into the air channel 916, the liquid pushes the sliding plug 915 to move left, and then magnetic fluid in the hydraulic pipeline 914 is pushed above the upper clamp 901 to lift the gravity center of the upper clamp 901, and meanwhile, the elastic resetting piece 905 is bent and drives the upper clamp 901 to press downwards, so that the PCBA is pressed; the pulling rope 912 is sequentially connected with a sliding plug 915, a fixed block 913 and a sliding block 911 from left to right, when the sliding plug 915 moves left, the pulling rope 912 can pull the sliding block 911 to move left, the magnetism isolating plate 909 is pulled into the channel, the magnetic strip 908 is exposed, and the magnetic conducting plate 904 pressed downwards is attracted to the magnetic strip 908, so that the clamping force of the upper clamping plate 901 is effectively improved, and the situations of translocation and poor contact of the PCBA plate due to unstable clamping are prevented; after the processing is finished, the mechanical arm takes out the PCBA board and lifts the upper clamping plate 901, the upper clamping plate 901 is reset through the elastic resetting piece 905, the air bag 906 is restored, the sliding plug 915 moves to the right, the magnetic isolation plate 909 is pushed out and covered above the magnetic strip 908, magnetism is isolated, meanwhile, the magnetic fluid flows back to the interior of the hydraulic pipeline 914 again, and the upper clamping plate 901 and the lower clamping plate 903 are enabled to keep a certain opening and closing angle.

The above description is only for the preferred embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art should be considered to be within the scope of the present application, and all equivalent substitutions or changes according to the technical solutions and modifications of the present application should be covered by the scope of the present application.

Claims

1. The utility model provides a PCBA test is power-on tool in advance, includes tool body (1), locating hole (2) have all been seted up to the four corners department of tool body (1), just install battery case (3) on tool body (1), the one end of battery case (3) is provided with electric quantity display screen (4), install processing panel (5) on tool body (1), the equal fixedly connected with guide block (6) of four corners department of processing panel (5), and the below of guide block (6) installs charging probe (7), a plurality of round holes (8), its characterized in that have been seted up on processing panel (5): a plurality of clamping components (9) are fixedly arranged at the upper end and the lower end of the processing panel (5);

the clamping assembly (9) comprises an upper clamping plate (901) and a lower clamping plate (903), the upper clamping plate (901) and the lower clamping plate (903) are rotatably connected through a rotating shaft (902), a plurality of elastic resetting pieces (905) are fixedly connected between the upper clamping plate (901) and the lower clamping plate (903), a plurality of groups of hydraulic pipelines (914) are arranged on the inner walls of the upper clamping plate (901) and the lower clamping plate (903), the hydraulic pipelines (914) in the same group are communicated through communicating hoses, a groove (907) communicated with the hydraulic pipeline (914) is arranged on the side wall of the upper end of the lower clamping plate (903) far away from the upper clamping plate (901), the bottom of the groove (907) is fixedly connected with a magnetic strip (908), the inner wall of the hydraulic pipeline (914) close to the groove (915) is slidably connected with a magnetic isolation plate (909), the inner wall of the hydraulic pipeline (914) close to the magnetic isolation plate (909) is slidably connected with a sliding block (911), a guide rod (910) is fixedly connected between the sliding block (911) and a sliding plug (911) is connected with a sliding plug (903) in the sliding block (903) through a sliding spring, the sliding block (903) and a sliding plug (911) is connected with a sliding plug (911) in the sliding block (903), and the space between the hydraulic pipeline (914) and the sliding plug (915) in the upper clamping plate (901) is filled with magnetic fluid, the side wall of the sliding block (911) is fixedly connected with a pull rope (912), the pull rope (912) penetrates through the fixing block (913) and is fixedly connected with the sliding plug (915), the side wall of the upper end of the lower clamping plate (903) is fixedly connected with a plurality of air bags (906), liquid is filled in the air bags (906), and an air channel (916) is communicated between the air bags (906) and the hydraulic pipeline (914).

2. The PCBA test pre-power-on jig of claim 1, wherein: elasticity resets piece (905) including hollow cylinder, and the inner wall fixedly connected with rubber stick (917) of hollow cylinder.

3. A PCBA test pre-power-on jig according to claim 2, and being characterized in that: the hollow cylinder is corrugated, the hollow cylinder is made of rubber materials, and the rubber rod (917) is made of flexible elastic materials.

4. The PCBA test pre-power-on jig of claim 1, wherein: the air bag (906) is in an oval ball shape, and a silica gel pad is fixedly connected to the upper surface of the air bag (906).

5. The PCBA test pre-power-on jig of claim 1, wherein: the number of the elastic reset pieces (905) is two, and the two elastic reset pieces (905) are symmetrically distributed on two sides of the upper clamping plate (901) and the lower clamping plate (903).

6. The PCBA test pre-power-on jig of claim 1, wherein: the side wall of the upper end of the upper clamping plate (901) is fixedly embedded with a magnetic conduction plate (904), and the magnetic conduction plate (904) is close to the upper end of the hydraulic pipeline (914).

7. A PCBA test pre-power-on jig according to claim 1, characterized in that: the rotating angle of the upper clamping plate (901) is 70-90 degrees, and a balancing weight is fixedly embedded in the inner wall of the upper end of the upper clamping plate (901).

8. The PCBA test pre-power-on jig of claim 1, wherein: the area of the magnetic isolation plate (909) is larger than that of the magnetic strip (908), and the magnetic isolation plate (909) adopts a hollow structure.

9. The PCBA test pre-power-on jig of claim 1, wherein: the elastic resetting piece (905) and the air bag (906) are on the same straight line, and the lower end of the elastic resetting piece (905) is far away from the vertical line where the uppermost end of the upper clamping plate (901) is located.

10. Use of a PCBA test pre-power-up jig according to any of claims 1-9, in which: the method comprises the following steps:

s1, when a PCBA board is placed on a lower clamping plate (903) by a manipulator, the manipulator and the PCBA can compress an air bag (906) and an elastic resetting piece (905) under the downward pressure, liquid in the air bag (906) is extruded into an air channel (916), the liquid can push a sliding plug (915) to move left, further, magnetic fluid in a hydraulic pipeline (914) is pushed to the upper part of the upper clamping plate (901) to lift the gravity center of the upper clamping plate (901), and meanwhile, the elastic resetting piece (905) is bent and drives the upper clamping plate (901) to press downwards, so that the PCBA is pressed;

s2, a sliding plug (915), a fixed block (913) and a sliding block (911) are sequentially connected with a pull rope (912) from left to right, the sliding plug (915) moves leftwards, the pull rope (912) can pull the sliding block (911) to move leftwards, the magnetic isolation plate (909) is pulled into the channel, the magnetic strip (908) is exposed, the magnetic conduction plate (904) pressed downwards is attracted with the magnetic strip (908), the clamping force of the upper clamping plate (901) is effectively improved, and the situations of translocation and poor contact of the PCBA plate due to unstable clamping are prevented;

s3, after the machining is finished, the upper clamping plate (901) is lifted while the PCBA is taken out by the manipulator, the upper clamping plate (901) is reset through the elastic reset piece (905), the air bag (906) is restored to the original state, the sliding plug (915) moves to the right, the magnetic isolation plate (909) is pushed out to cover the upper part of the magnetic strip (908), the magnetism is isolated, and meanwhile, the magnetic fluid flows back into the hydraulic pipeline (914) again to enable the upper clamping plate (901) and the lower clamping plate (903) to keep a certain opening and closing angle.