CN110202234A - A kind of Piezoelectric Driving automatic spray printing system - Google Patents

Abstract

The invention discloses a piezoelectric-driven automatic inkjet printing system, an industrial computer, and a motion control system, a inkjet printing system, and a machine vision system connected electrically with the industrial computer; the motion control system includes a motion platform on which a fixed inkjet printing system is installed , which is used to receive the movement command from the industrial computer to control the movement track of the printing system along the pad; The solder joints are printed on the disk; the ranging sensor is used to obtain the vertical distance information from the nozzle to the pad; the machine vision system includes a CCD camera, and the CCD camera is used to obtain and transmit the image of the pad solder joints. The invention combines piezoelectric drive and control technology with machine vision and motor feedback technology, completely based on program control, automatically adjusts the frequency of spray printing according to the movement speed of the motion platform and the distance measurement information, and realizes the precision of solder spray printing , intelligent automation.

Description

A Piezoelectric Drive Automatic Printing System

technical field

The invention relates to the technical field of SMT production equipment, in particular to a piezoelectric-driven automatic inkjet printing system.

Background technique

As we all know, the first step in SMT chip processing is to make a stencil mold according to the design of the PCB board, and then use the stencil mold to print solder on the PCB board, and the production process of the stencil mold usually takes more than 24 hours At this time, for small batch orders that are eager to produce, it will greatly affect the efficiency. With the miniaturization, densification, and softening of electronic products, stacked packaging, recessed circuit boards, high-mixing and flexible boards are the development directions, and the traditional solder distribution technology can no longer meet the existing technology market.

Solderjet printing enables the printing sequence to be automatically spread out and aligned based on PCB fiducials. The non-contact technique is independent of any substrate warpage. However, at present, the inkjet printing technology is directly used for SMT solder injection, and its intelligent control accuracy is low, and it is impossible to effectively control the printing position of each solder joint on the pad, as well as the capacity and size of the solder joints, and the operator cannot conveniently print for the printed board. The pads on the board adjust the solder joint capacity and shape.

Therefore, how to provide a piezoelectric-driven automatic inkjet printing system with fast production speed and high degree of intelligent control is an urgent problem to be solved by those skilled in the art.

Contents of the invention

The invention provides an automatic controlled high-speed piezoelectric driven automatic jet printing system. For the shortcoming of prior art, concrete scheme is as follows:

A piezoelectric-driven automatic inkjet printing system, comprising: an industrial computer, and a motion control system, an inkjet printing system, and a machine vision system electrically connected to the industrial computer; wherein,

The motion control system includes a motion platform, on which the printing system is installed and fixed, and is used to receive movement instructions from the industrial computer to control the printing system along the X-axis direction, Y-axis direction and The movement trajectory in the Z-axis direction;

The inkjet printing system includes a piezo-driven injector, and a ranging sensor fixed on the nozzle of the piezo-electrically-driven injector, and the piezo-electrically driven injector is used to receive the inkjet printing command of the industrial computer and send to the Printing solder joints on the pad; the distance measuring sensor is used to obtain the vertical distance information from the nozzle to the pad, and feed it back to the industrial computer;

The machine vision system includes a CCD camera, the CCD camera is electrically connected to the industrial control machine, and is used to transmit the solder joint image of the pad;

The industrial computer controls the movement of the inkjet printing system and the execution of the jetting action, and adjusts the movement distance in the Z-axis direction in real time according to the vertical distance information, and displays the image of the pad solder joint in real time.

The invention can accurately identify printed boards with different structures, including lead frame, 3D pit, QFN leadless package, through-hole reflow soldering, etc. For the requirement of different solder printing heights, there is no need to preset injector welding for different weldments in different areas of the pad, which simplifies the operation process and realizes the intelligent control of solder printing.

Preferably, the motion platform includes an X-axis slide rail, a Y-axis slide rail and a Z-axis slide rail, the piezoelectric drive injector is installed on the Z-axis slide rail, and the Z-axis slide rail is vertically installed on the Z-axis slide rail. The X-axis slide rail is vertically erected on the Y-axis slide rail.

Preferably, the X-axis slide rail, the Y-axis slide rail and the Z-axis slide rail all use a servo motor to drive the ball screw structure, and the servo motor is electrically connected to the industrial computer; the piezoelectrically driven injector passes through the slide table One is slidingly connected to the top surface of the Z-axis lead screw; the bottom surface of the Z-axis lead screw is fixed on the second slide table of the X-axis lead screw, and the Z-axis lead screw is slidably connected to the second slide table of the X-axis lead screw. on the X-axis screw; one end of the X-axis screw is vertically slidably connected to the Z-axis screw.

Preferably, the other end of the X-axis lead screw is slidably connected to a guide rail, and the guide rail is arranged parallel to the Y-axis lead screw.

Through the trajectory control of the motion platform, the position of the welding spot can be precisely controlled, combined with the feedback information from the ranging sensor, real-time fine-tuning of the height of the injector ensures the stability and accuracy of the welding process.

Preferably, the bottom of the piezoelectrically driven injector is provided with the nozzle, and one side of the nozzle is fixedly connected to the distance measuring sensor.

Preferably, a constant pressure air supply system is also included, the constant pressure air supply system provides pressure to the solder tank, the constant pressure air supply system includes: an air compressor, a pressure reducing valve; the air compressor passes through the pressure reducing valve It communicates with the top of the solder tank, and the bottom of the solder tank communicates with the injection cavity of the piezo-electrically driven injector through a feed pipe.

Preferably, the jet printing system further includes a temperature controller, and the temperature controller is connected to the heater inside the piezo-driven injector.

Preferably, the heater is installed outside the injection cavity for constant temperature heating of the solder in the injection cavity.

The temperature controllable function of the heater can effectively adapt to the different solder volumes required by different weldments, and accurately adjust the temperature of solder with different capacities in the injection cavity.

Preferably, the piezoelectric-driven injector includes a piezoelectric actuator connected to the industrial computer for driving the valve stem to move vertically to impact the solder in the injection cavity Formed solder droplets are ejected from the nozzles.

Compared with the prior art, the present invention has the following beneficial effects:

The present invention discloses a piezoelectric-driven automatic printing system, which needs to realize intelligent control, combines piezoelectric drive and control technology with machine vision and motor feedback technology, and is completely based on program control. The speed of movement automatically adjusts the frequency of printing, reduces the probability of workpiece repair, and reduces the number of operators, realizes precision and standardized manufacturing, and saves a lot of manpower and financial resources.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention, and those skilled in the art can also obtain other drawings according to the provided drawings without creative work.

Fig. 1 is the functional block diagram of a kind of piezoelectric drive automatic printing system of the present invention;

Fig. 2 is a structure diagram of a motion platform of a piezoelectric-driven automatic printing system of the present invention;

Fig. 3 is a schematic diagram of the internal structure of the injector of the present invention.

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.

This embodiment provides a piezoelectric-driven automatic printing system, referring to the schematic block diagram of the piezoelectric-driven automatic printing system disclosed in Figure 1, including: an industrial computer 10, and a motion control system electrically connected to the industrial computer 10, A jet printing system and a machine vision system; wherein, the motion control system includes a motion platform on which a fixed jet printing system is installed to receive movement instructions from the industrial computer 10 to control the jet printing system along the X-axis direction and the Y-axis direction of the pad and the motion trajectory in the Z-axis direction; the inkjet printing system includes a piezo-driven injector, and a ranging sensor fixed on the nozzle of the piezo-electrically-driven injector, and the piezoelectric-driven injector is used to receive the printing instruction of the industrial computer 10 and send The welding pad is sprayed with solder joints; the ranging sensor is used to obtain the vertical distance information from the nozzle to the pad, and feeds back to the industrial computer 10; the machine vision system includes a CCD camera 6, and the CCD camera 6 is electrically connected to the industrial computer 10 for transmission Solder joint image of the pad; the industrial computer 10 controls the movement of the printing system and the execution of the spraying action, and adjusts the moving distance in the Z-axis direction in real time according to the vertical distance information, and displays the solder joint image of the pad in real time.

The motion platform includes an X-axis slide rail, a Y-axis slide rail and a Z-axis slide rail. The X-axis slide rail, the Y-axis slide rail and the Z-axis slide rail all adopt a servo motor to drive a ball screw structure, and the servo motor is electrically connected to the industrial computer 10; The piezoelectric drive injector is slidably connected to the top surface of the Z-axis lead screw 31 through the first slide 310; the bottom surface of the Z-axis lead screw 31 is fixed on the second slide 320 of the X-axis lead screw 32, and the Z-axis lead screw 31 is Stage 2 320 is slidably connected to the X-axis screw 32 ; one end of the X-axis screw 32 is vertically slidably connected to the Z-axis screw 31 . The other end of the X-axis lead screw 32 is slidably connected to the guide rail 34 , and the guide rail 34 is arranged parallel to the Y-axis lead screw 33 .

Referring to the accompanying drawing 2 of the specification, the piezoelectric drive injector includes a drive base 1 and a feed base 2 located at the bottom of the drive base 1; a fixed frame 11 is installed in the drive base 1, and a piezoelectric actuator 12, The lever structure 13 and the positioning screw 14; the piezoelectric actuator 12 is connected to the industrial computer 10, the displacement output end of the piezoelectric actuator 12 abuts against the action arm 131 of the lever structure 13, and the end of the action arm 131 is vertically fixed with the striker 3 The positioning screw 14 is located at the bottom of the driving seat 1; the inside of the feeding seat 2 is provided with a positioning nut 21 that matches the positioning screw 14, and the bottom of the positioning nut 21 is threaded with an adjusting nut 22, and the adjusting nut 22 is provided with an injection chamber 221 The bottom of the feeding seat 2 is provided with a nozzle 23, and the injection chamber 221 is connected to the nozzle 23; The spring 31 and the spring seat 22 are sleeved on the striker 3 ; wherein, the spring seat 22 is fixed on the top of the positioning screw 14 ; the spring 31 is limited between the action arm 131 and the spring seat 22 .

One side of the nozzle 23 is fixedly connected to the distance measuring sensor 4, and the distance measuring sensor 4 moves with the piezoelectrically driven injector to measure the vertical distance from the distance measuring sensor 4 to the welding pad in real time, and feedback, and the position is determined after the industrial computer 10 judges and processes Perform solder jetting jobs.

The jet printing system also includes a temperature controller 5, which is connected with a heater 51 inside the piezo-electrically driven injector. The heater 51 is installed outside the injection cavity 221 for constant temperature heating of the solder in the injection cavity 221, and the heater 51 adopts a heating coil structure.

The spray printing system is connected with a constant pressure air supply system, which provides pressure to the solder tank. The constant pressure air supply system includes: an air compressor, a pressure reducing valve; the air compressor is connected to the top of the solder tank through the pressure reducing valve, The bottom of the solder pot communicates with the injection cavity of the piezo-electrically driven injector through the feed pipe 24 .

The working principle of the present invention is as follows:

After the industrial computer is started and the printing operation is started, the motion platform in the motion control system controls the operating frequency and frequency of the servo motors of the X-axis slide rail, Y-axis slide rail, and Z-axis slide rail according to the welding pad welding position coordinates imported into the industrial computer. Direction, drive the piezo-driven injector to perform the printing task according to the predetermined track.

During the printing process, the industrial computer controls the output displacement of the piezoelectric actuator to control the rapid movement of the striker in the injection cavity and the nozzle, thereby forming an instantaneous pressure, the impulse to the solder and the flow rate of the nozzle outlet decrease with the increase of the nozzle diameter. Small, so in the process of solder pressure accumulation between the injection chamber and the nozzle, the pressure caused by the striker impact determines the volume of the solder droplet. In view of the different requirements of the solder joints of different weldments, the ranging sensor obtains the vertical distance from the solder joint position to the nozzle in real time, and sends it to the industrial computer to judge the height of the required solder joints, so as to determine the specific time to stay at this point.

After the printing is finished, the CCD camera is used to capture and transmit the images of the pads and solder joints, and the printing results are rechecked.

The above is a detailed introduction to a piezoelectric-driven automatic printing system provided by the present invention. In this paper, specific examples are used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only used to help understand the present invention. method and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation and scope of application. In summary, the content of this specification should not be understood as Limitations on the Invention.

In this document, relational terms such as first and second etc. are used only to distinguish one entity or operation from another without necessarily requiring or implying any such relationship between these entities or operations. Actual relationship or sequence. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

Claims (9)

1. A piezoelectric driven automatic jet printing system is characterized by comprising: the printing system comprises an industrial personal computer, and a motion control system, a jet printing system and a machine vision system which are electrically connected with the industrial personal computer; wherein,

the motion control system comprises a motion platform, the jet printing system is fixedly arranged on the motion platform and used for receiving a moving instruction of the industrial personal computer to control the motion tracks of the jet printing system along the X-axis direction, the Y-axis direction and the Z-axis direction of the bonding pad;

the jet printing system comprises a piezoelectric driving ejector and a distance measuring sensor fixed on a nozzle of the piezoelectric driving ejector, wherein the piezoelectric driving ejector is used for receiving a jet printing instruction of the industrial personal computer and jet printing welding points to the welding disc; the distance measuring sensor is used for acquiring the vertical distance information from the nozzle to the bonding pad and feeding back the information to the industrial personal computer;

the machine vision system comprises a CCD camera which is electrically connected with the industrial personal computer and used for transmitting the welding spot image of the welding pad;

the industrial personal computer controls the movement of the spray printing system and the execution of the spraying action, adjusts the moving distance in the Z-axis direction in real time according to the vertical distance information, and displays the welding spot image of the welding pad in real time.

2. The piezoelectric driven automatic jet printing system according to claim 1, wherein the moving platform comprises an X-axis slide rail, a Y-axis slide rail and a Z-axis slide rail, the piezoelectric driven ejector is mounted on the Z-axis slide rail, the Z-axis slide rail is vertically mounted on the X-axis slide rail, and the X-axis slide rail is vertically erected on the Y-axis slide rail.

3. The piezoelectric driving automatic jet printing system according to claim 2, wherein the X-axis slide rail, the Y-axis slide rail and the Z-axis slide rail are all of a ball screw structure driven by a servo motor, and the servo motor is electrically connected with the industrial personal computer; the piezoelectric driving ejector is connected to the top surface of the Z-axis lead screw in a sliding mode through a sliding table I; the bottom surface of the Z-axis screw rod is fixed on a second sliding table of the X-axis screw rod, and the Z-axis screw rod is connected to the X-axis screw rod in a sliding mode through the second sliding table; one end of the X-axis lead screw is vertically connected with the Z-axis lead screw in a sliding manner.

4. The piezoelectric driven automatic jet printing system as claimed in claim 3, wherein the other end of the X-axis lead screw is slidably connected to a guide rail, and the guide rail is arranged in parallel with the Y-axis lead screw.

5. The piezoelectric driven automatic jet printing system as claimed in claim 1, wherein the nozzle is arranged at the bottom of the piezoelectric driven ejector, and one side of the nozzle is fixedly connected with the distance measuring sensor.

6. The piezoelectric driven automatic jet printing system according to claim 1, further comprising a constant pressure gas supply system which supplies pressure to the solder pot, the constant pressure gas supply system comprising: an air compressor, a pressure reducing valve; the air compressor is communicated to the top of the solder pot through the pressure reducing valve, and the bottom of the solder pot is communicated with the material injection cavity of the piezoelectric driving ejector through a feeding pipeline.

7. A piezo-electrically driven automated inkjet printing system according to claim 6, further comprising a temperature controller connected to a heater inside the piezo-electrically driven ejector.

8. A piezo-electric driven automated jet printing system according to claim 7, wherein the heater is mounted outside the feed chamber for thermostatically heating the solder in the feed chamber.

9. A piezoelectric driven automatic jet printing system as claimed in claim 6, wherein the piezoelectric driven ejector comprises a piezoelectric actuator connected with the industrial personal computer and used for driving the valve rod to move vertically and impacting the solder in the material injection cavity to form solder drops to be ejected from the nozzle.