CN113260154B

CN113260154B - Method for spray printing two-dimensional code on printed board

Info

Publication number: CN113260154B
Application number: CN202110450062.2A
Authority: CN
Inventors: 李清华; 张仁军; 胡志强; 牟玉贵; 杨海军
Original assignee: Inno Circuits Ltd
Current assignee: Inno Circuits Ltd
Priority date: 2021-04-25
Filing date: 2021-04-25
Publication date: 2022-12-13
Anticipated expiration: 2041-04-25
Also published as: CN113260154A

Abstract

The invention provides a method for spray-printing a two-dimensional code on a printed board. The method comprises the following steps: determining spray printing coordinates on a printed board; determining ink-jet data according to the two-dimensional code information, wherein the ink-jet data comprises at least one of data matrix information and a serial number and a two-dimensional code encoding format, and the data matrix information comprises a client code and/or a periodic code; based on ink-jet data, utilizing ink-jet equipment to spray-print at least 2 times at a spray-printing coordinate position on a printing plate so as to spray-print a two-dimensional code, wherein the ink-jet equipment is provided with 2-8 nozzles, and an ink path part of the ink-jet equipment comprises a negative pressure control mechanism, a primary ink box, a primary filtering mechanism, a power mechanism, a secondary ink box and a secondary filtering mechanism; and drying the two-dimensional code subjected to jet printing. The beneficial effects of the invention include: a screen printing plate is not needed, and the link of carving by laser equipment can be saved; the ink jet machine is directly adopted for jet printing, so that the process flow and the processing steps are reduced, the production cost is reduced, and the effects of environmental protection and energy conservation are achieved.

Description

Method for spray printing two-dimensional code on printed board

Technical Field

The invention relates to the field of two-dimensional code manufacturing, in particular to a method for spray-printing a two-dimensional code on a printed board.

Background

The two-dimensional Code is also called as a two-dimensional Bar Code, a common two-dimensional Code is a QR Code, which is a popular coding mode on mobile equipment in recent years, and compared with the traditional Bar Code, the two-dimensional Code can store more information and represent more data types. After a printed board (fully called as a printed circuit board) is provided with mounted components, more and more users carve two-dimensional codes on the printed board for the convenience of tracing related information and parameters.

And the processing mode of the two-dimensional code on the conventional printed board is as follows: (1) adopting screen printing to form white oil blocks for the character process when the printed board is processed; (2) before components are welded for a printed board delivered to a customer, a two-dimensional code is carved on a white oil block by using laser equipment, for example, a schematic diagram of the two-dimensional code carved on the white oil block shown in fig. 1. The two-dimensional code jet printing process is long in flow, tedious in procedure, large in equipment investment and very low in efficiency.

Disclosure of Invention

In view of the deficiencies in the prior art, the present invention is directed to solving one or more of the problems in the prior art set forth above. For example, one of the objectives of the present invention is to provide a method for spray-printing a two-dimensional code on a printed board, so as to shorten the process flow.

In order to achieve the above object, in one aspect, the present invention provides a method for spray-printing a two-dimensional code on a printed board, which is characterized by comprising the following steps: determining spray printing coordinates on a printed board; determining ink-jet data according to the provided two-dimensional code information, wherein the ink-jet data comprises at least one of data matrix information and a serial number and a two-dimensional code encoding format, and the data matrix information comprises a client code and/or a periodic code; based on ink-jet data, ink-jet equipment is used for carrying out jet printing for at least 2 times at a jet printing coordinate position on a printing plate so as to jet print a two-dimensional code, wherein the ink-jet equipment is provided with 2-8 nozzles, an ink path part of the ink-jet equipment comprises a negative pressure control mechanism, a first-stage ink box, a first-stage filtering mechanism, a power mechanism, a second-stage ink box and a second-stage filtering mechanism, wherein the first-stage ink box and the second-stage ink box are sequentially connected in an ink flowing mode and are finally connected to the nozzles; and drying the two-dimensional code subjected to jet printing.

Furthermore, the ink-jet equipment also comprises a matched auxiliary mechanism, wherein the auxiliary mechanism comprises a mechanical arm and an automatic plate turnover machine, the mechanical arm can complete feeding and discharging, and the automatic plate turnover machine can turn over the printed board to complete double-sided jet printing.

Furthermore, the auxiliary mechanism can also comprise a confluence machine, a flow dividing machine, a steering machine, a positioning machine, a temporary storage machine and a horizontal conveying belt.

Further, after the drying process, the method may further include that the method may further include at least one of an image inspection and a reading test, wherein the image inspection may include: the method comprises the following steps of collecting an integral image of the two-dimensional code, comparing the integral image with an image template, and judging whether the appearance of the two-dimensional code is qualified according to a comparison result, wherein the qualification comprises the following steps: the size and the dimension of the whole image are qualified, the appearance of the whole image is qualified, and the thickness of the two-dimensional code line is qualified; the read test may include: the two-dimensional code is read to determine whether correct information can be read from the two-dimensional code.

Further, the length and the width of the two-dimensional code can be at least 5mm, the minimum width of the characters can be 3 mils, and the minimum height can be 20 mils.

Further, the character effect of the two-dimensional code is positive.

Furthermore, the thickness of the ink of the two-dimensional code which is sprayed out is 20-40 μm.

Further, the method may further comprise the steps of: the serial number is formatted according to customer requirements.

Further, the temperature of the drying treatment can be 130-170 ℃, and the time can be 40-80 min.

Further, the ink for the ink jet device may have a viscosity of 22 to 26cps at room temperature, a surface tension of 20 to 40mN/m, and an average particle diameter of 220 to 260nm.

Further, the step of determining ink ejection data may comprise: and processing the provided two-dimensional code information by using a script Genesis-V8 to determine the ink-jet data.

Further, the printed circuit board may be a printed circuit board including a solder resist bridge made of a dry film solder resist, and the printed circuit board is prepared by the following method:

preparing a substrate, wherein the substrate comprises a metal layer and an insulating layer; preparing a solder resist dry film; vacuum film pasting: vacuum-attaching the solder-resisting dry film on the substrate at the temperature of 60-70 ℃, wherein the vacuum time is more than 15s, and the film attaching time is 15-30 s; exposing the area needing welding in the surface area of the substrate after film pasting in an exposure and development mode to expose the metal layer; and curing the developed substrate, and forming a solder mask bridge on the obtained printed circuit board.

Further, the step of preparing the substrate may include performing a pre-solder-resist treatment on the substrate, wherein a grinding mark having a width of 10 to 15mm may be formed on the pre-solder-resist treated substrate, and a medium roughening undercut amount of the pre-solder-resist treated substrate may be 0.5 to 1.5 μm.

Further, the pre-treatment of solder resist may include pickling, plate grinding, sand blasting, water washing, and dry plate treatment.

Further, when the thickness of the substrate exceeds 0.4mm, the resistance welding pretreatment can comprise acid washing, water jet washing, overflow washing, plate grinding, sand blasting, sewage flushing, first pressurizing water washing, ultrasonic wave immersion washing, high-pressure swinging water washing, second pressurizing water washing, HF water washing, third pressurizing water washing, cleaning water washing, drying by suction, strong wind drying, hot air drying and cooling which are sequentially carried out.

Further, when the thickness of the substrate is less than 0.4mm, the resistance welding pretreatment can comprise acid washing, water jet washing, overflow water washing, plate grinding, sand blasting, sewage flushing, first pressurizing water washing, ultrasonic wave soaking, second pressurizing water washing, third pressurizing water washing, clear water washing, drying, strong wind drying, hot air drying and cooling which are sequentially carried out. In the plate grinding step, a grinding brush of the plate grinding machine is closed, and the substrate is obliquely placed into the plate grinding machine at an angle of 20-50 degrees, so that the plate angle of the substrate is firstly put into the plate grinding machine.

Further, the pickling concentration may be 3 to 5wt%. The pickling pressure can be 2.0 plus or minus 0.5Kg/cm ² . The pressure of the overflow water washing can be 1.5 plus or minus 0.5Kg/cm ² . The medium coarsening and etching amount can be 0.5-1.5 μm. The width of the generated grinding crack can be 10-15 mm. The volume percentage concentration of the carborundum sprayed by the sand blasting machine can be 15-25%, and the sand blasting pressure can be 2.0 +/-0.5 Kg/cm ² . The washing pressure of the flushing water can be 1-1.5 Kg/cm ² The HF washing pressure may be 2.0 + -0.5 Kg/cm ² The pressure of the three times of pressurized water washing can be 2.0 plus or minus 0.5Kg/cm ² The high-pressure swing water washing can be 10-15 Kg/cm ² . The blowing pressure of strong wind can be 8-15 Kpa. The drying temperature can be 95 +/-5 ℃.

Further, the thickness of the dry film of solder resist may be 20 to 60 μm.

Further, the dry film solder resist may be composed of three parts of a polyethylene protective film, a photoresist film and a carrier polyester film, the polyethylene protective film may have a thickness of 20 to 30 μm, the photoresist film may have a thickness of 10 to 100 μm, and the carrier polyester film may have a thickness of 20 to 30 μm.

Further, in the step of vacuum film pasting, the film pasting pressure can be 0.3-0.8 Kg/cm ² The thickness of the film copper can be 18-105 μm.

Further, in the exposure step, the number of exposure steps may be 9 to 11, and the exposure energy may be 200 to 600mj.

Further, the developing step may include: after the exposure step, the exposed part is developed by using an alkaline solution, the mass percentage concentration of the alkaline solution can be 0.8-1.2%, the pH value of the alkaline solution is more than or equal to 10.5, and the development time can be 60-100 s.

Further, in the curing step, the temperature can be controlled between 150 ℃ and 160 ℃, and the curing time can be 60-70 min.

Furthermore, a solder resistance bridge is formed on the printed board, and the minimum width of the solder resistance bridge can reach 2 mils.

Compared with the prior art, the beneficial effects of the invention can comprise at least one of the following:

(1) The invention does not need a screen printing plate or a link of subtracting the carving of laser equipment after the screen printing.

(2) The invention directly adopts the ink jet machine for spray printing, reduces the process flow and the processing steps, reduces the production cost and simultaneously plays a role in environmental protection and energy saving.

(3) The two-dimensional code sprayed and printed on the printed board can trace the root source of the product and support the inquiry of various production periods, serial numbers, batch numbers, daughter board numbers and unit numbers.

(4) The customer can enter information by directly scanning the two-dimensional code, flow conversion is reduced, and efficiency can be improved.

Drawings

The above and other objects and features of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

fig. 1 is a schematic diagram illustrating a two-dimensional code engraved on a white oil block in the conventional art;

fig. 2 is a schematic view illustrating a two-dimensional code printed by a method of inkjet printing a two-dimensional code on a printed circuit board according to an exemplary embodiment of the present invention.

Detailed Description

Hereinafter, a method of inkjet printing a two-dimensional code on a printed board of the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments.

In an exemplary embodiment of the present invention, the method for spray-printing the two-dimensional code on the printed board may include the steps of:

and S10, determining ink-jet data according to the two-dimensional code information provided by the customer.

The ink-jet data can include at least one of data matrix information and serial number, and two-dimensional code encoding format. For example, the inkjet data may include data matrix information, serial numbers, and two-dimensional code encoding formats. As another example, the inkjet data may include a serial number and a two-dimensional code encoding format. As another example, the inkjet data may include data matrix information and a two-dimensional code encoding format. The data matrix information may include a client code and/or a period code.

And S20, performing jet printing on the printing plate for at least 2 times by using an ink jet device based on the ink jet data so as to jet print the two-dimensional code.

And S30, drying the two-dimensional code subjected to jet printing.

Wherein, the drying temperature can be 130-170 ℃, such as 140, 150, 160 ℃ and the like; the drying time is 40-80 min, such as 50, 60, 70min.

In this embodiment, the method may further include determining a jet printing coordinate, that is, a position where the two-dimensional code needs to be jet printed, on the printed board.

In another exemplary embodiment of the invention, the two-dimensional code can be directly jet-printed by a text ink jet printer, each board uses an independent two-dimensional code, the information of the two-dimensional code is changed in the form of serial numbers, and a customer directly scans the two-dimensional code to enter information when using the two-dimensional code, so that the process conversion is reduced and the efficiency is improved.

The method for spray printing the two-dimensional code on the printed board can comprise the following steps:

A. according to the two-dimension code information (namely, the two-dimension code coding information) provided by the user, the two-dimension code special script Genesis-V8 is used for processing, and the ink-jet data is obtained. The script Genesis-V8 can convert the coding information of the two-dimensional code into a graph of the two-dimensional code through V8 software. The ink-jet data may include a dynamic two-dimensional code encoding format, data matrix information (client code, periodic code) and a desired serial number.

B. The two-dimensional code is jet printed by an ink jet device (also called an ink jet), specifically:

(1) ink-jet data is called in the man-machine interface of the ink-jet machine, and the label icon is lightened to indicate that the dynamic two-dimensional code (label) needs to be set in the file.

(2) Entering a label setting interface → A filling cycle → B selecting coding format → C selecting number scale → C checking reverse color → D selecting serial number format → D filling serial number starting number → D checking automatic increment → F inputting data matrix information → F selecting information needing to be added → saving exit.

(3) The serial number formats [ PCS ], [ PNL ], [ PCS ] [ PNL ], [ PNL ] [ PCS ] are selected according to the requirements of the user. Wherein, PNL refers to the working dimension of the printed board processing process, and PCS refers to the delivery dimension, for example, 1PNL = 5-8 PCS, and for example, 1PNL =7PCS.

Checking according to a serial number format: auto-increment, fill in sequence number start number: for example: 0001 (typically four digits), and then selects the information that needs to be added: such as period, serial number, material number name, etc., and finally filling in data matrix information provided by the client: input until ID figure.

(4) And then, spraying and printing the first piece, and automatically spraying and printing two-dimensional code information with different serial numbers at the appointed position.

(5) The ink jet equipment is used for jetting and printing twice in a high-definition mode by using 1800i four nozzles of the ink jet equipment, and the alignment accuracy is +/-1.2 mil. Wherein, four shower nozzles are arranged side by side, and the figure of spouting the seal is seamless butt joint, shows simultaneously.

In the high-definition mode, the ink jet speed can be 400-600 mm/s, the ink jet flow rate is 20-40 ml/min, the number of times of jet printing is related to the thickness of the ink, the thickness of two times is 20-40 mu m, the more the times, the thicker the ink, and the same the jet printing of the two times.

In this embodiment, fig. 2 shows a schematic diagram of a two-dimensional code ejected by the present invention. The minimum size of the jet-printed two-dimensional code is 5 × 5mm, that is, the length and width of the two-dimensional code are shown in fig. 2; the minimum width of the text can be 3mil, that is, fig. 2 shows the width of a white line in the two-dimensional code; the minimum height of the text can be 20 mils, i.e., fig. 2 shows the height of the white boxes in the two-dimensional code.

If the above-mentioned size, width and height requirements are less than the respective lower limit values, the ink jet apparatus cannot eject the two-dimensional code well, and if ejected, the character blurring or clustering may occur due to ink flow. Of course, the dimensions mentioned above cannot be too large in view of the actual space of the printed board panel.

In this embodiment, the character effect of the jet printing two-dimensional code is a positive film, and the two-dimensional code theme is composed of character oil and background solder resist oil.

In this embodiment, the thickness of the ink for jet printing the two-dimensional code of the present invention may be 20 to 40 μm, for example, 25, 30, 35 μm. The thickness of the printing ink is controlled to be 20-40 mu m, the two-dimensional code can present a three-dimensional effect, if the printing ink is too thick, the printing ink needs to be sprayed for many times, the efficiency is influenced, if the printing ink is too thin, the printing ink is not uniformly sprayed, and the green solder resist oil cannot be covered by the white characters.

In this embodiment, after the two-dimensional code is jet printed, an oven may be used to dry the two-dimensional code, where the drying temperature may be 150 degrees celsius and the drying time may be 60 minutes.

In this embodiment, the ink for the ink jet device may have a viscosity of 22 to 26cps, for example, 23, 24, 25cps, etc., a surface tension of 20 to 40mN/m, for example, 25, 30, 35mN/m, etc., and an average particle diameter of 220 to 260nm, for example, 230, 240, 250nm, etc., at room temperature.

In this embodiment, the ink path component of the ink jet device may include a primary ink cartridge, a primary filter mechanism, a power mechanism, a secondary ink cartridge, a secondary filter mechanism, and a negative pressure control mechanism.

The first-stage ink box, the first-stage filtering mechanism, the power mechanism, the second-stage ink box and the second-stage filtering mechanism can be sequentially arranged in an ink flowing mode and can be connected with one another through pipelines. The ink filtered by the secondary filter layer mechanism flows to the spray head.

Wherein, first-class ink horn and second grade ink horn can both save printing ink, and the second grade ink horn can save the printing ink that conveys from first-class ink horn. The power mechanism may include a pump that enables the transfer of ink.

The primary filter mechanism can filter ink flowing from the primary ink cartridge to the secondary ink cartridge. The second-stage filtering mechanism can filter the ink from the second-stage ink box to the spray head. The invention can reduce the risk of the spray head being blocked by twice filtration of the primary and secondary filtering mechanisms.

The negative pressure control mechanism can perform negative pressure control on the secondary ink box to keep the liquid level in a stable state. The pressure control can be accurate to 0.01kpa. A pressure sensor can be arranged in the secondary ink box to realize accurate control of the pressure. The pressure sensor is connected with the negative pressure control mechanism.

In this embodiment, the ink path member of the ink jet apparatus may further include a first heating mechanism capable of heating the ink in the primary ink tank and/or a second heating mechanism capable of heating the ink in the secondary ink tank. The ink printing device can greatly improve the smoothness and stability of the ink by arranging the heating mechanism.

In this embodiment, both sides of the PCB may be subjected to inkjet printing, and the inkjet printing process may be feeding, first side inkjet printing, turning, second side inkjet printing, and discharging.

In this embodiment, the inkjet device further includes a supporting auxiliary mechanism, and the auxiliary mechanism includes a manipulator and an automatic board turnover machine, where the manipulator can complete the loading and unloading work, and the automatic board turnover machine can turn over the PCB to complete the two-sided inkjet printing.

In this embodiment, the auxiliary mechanism may further include a converging machine, a diverging machine, a steering machine, a positioning machine, a temporary storage machine, a horizontal conveyor belt, and the like, which may be conventional mechanisms in the art.

In this embodiment, the auxiliary mechanism may further include at least one of a visual detection mechanism and a two-dimensional code reading mechanism.

The visual detection mechanism can comprise a photographing unit and a control unit, the photographing unit can collect the whole image of the two-dimensional code, the control unit can compare the whole image with the image template, and whether the appearance of the two-dimensional code is qualified or not is judged according to the comparison result. The qualifying comprises: the size and the dimension of the whole image are qualified, the appearance of the whole image is qualified, and the thickness of the two-dimensional code line is qualified. Further, the visual inspection mechanism may further include a lighting unit to enable the photographing unit to capture a suitable image. The lighting unit may be a lamp strip having a plurality of light emitting members, each of which projects light to the two-dimensional code at an angle that is not exactly the same. The shape of the light strip may conform to or resemble the outline of a two-dimensional code, such as a rectangle.

The two-dimensional code reading mechanism can comprise a code scanning machine, and the code scanning machine can read the two-dimensional code to judge whether correct information can be read from the two-dimensional code.

In this embodiment, the present invention may use an LED curing light source to achieve curing. The LED curing light source has long service life, is energy-saving and environment-friendly, does not need frequent replacement and maintenance, and can realize instant curing.

After jet printing is finished, the two-dimensional code and solder resist ink can be baked together, and a high-temperature long-time baking process of characters is saved.

The ink jet device can have a double station, i.e. containing 2 printing and transport lines working in parallel, and even if a failure occurs on one line, the other line is kept on production. The ink jet device may also have a natural downtime backup function.

The core of the ink jet device may comprise 2 jet printing units and an automatic plate turnover arranged in the middle, for example, the core can be used for the jet printing of a PCB with four open panels. Each jet printing unit can comprise the ink path component and a plurality of jet heads connected with the ink path component.

The ink-jet equipment can realize automatic production in a horizontal transmission mode, and the mass production efficiency can reach 7 pieces/min at most.

In this embodiment, the method may further include printing the solder resist using the inkjet apparatus described above.

In this embodiment, after the drying process, the method may further include the steps of: the method comprises the following steps of collecting an integral image of the two-dimensional code, comparing the integral image with an image template, and judging whether the appearance of the two-dimensional code is qualified according to a comparison result, wherein the qualification comprises the following steps: the size and the dimension of the whole image are qualified, the appearance of the whole image is qualified, and the thickness of the two-dimensional code line is qualified.

The image template may be a template obtained by training a series of qualified two-dimensional codes by using a deep learning algorithm, or may be a template obtained by collecting a certain number of qualified images of the two-dimensional codes, extracting information of corresponding images according to characteristics of the two-dimensional codes, and synthesizing an average template (i.e., the image template), where the template includes "average characteristics" of the two-dimensional codes, and the template includes "average characteristics" of the two-dimensional codes.

Further, the qualifying may further include: the color of the two-dimensional code lines is consistent.

In this embodiment, after determining that the shape is qualified, the reading test may include: the two-dimensional code is read to determine whether correct information can be read from the two-dimensional code.

In a further exemplary embodiment of the present invention, based on the above two exemplary embodiments, the printed circuit board is a printed circuit board including a solder resist bridge made of a dry film solder resist, and the process of preparing the printed circuit board includes: entering a board → pre-treatment of solder resist → vacuum film application → exposure → development → curing → board discharge.

S1, entering a plate.

A substrate is prepared, which is used to form a support and to form a desired circuit. The substrate may be composed of a metal layer and an insulating layer. The thickness of the substrate may be 3.0mm or less, for example, 1.0 to 2.0mm.

In this embodiment, the method may further include performing a solder resist pretreatment on the substrate to roughen and remove the surface of the substrate, so that the copper surface forms a micro rough interface, thereby enhancing the bonding force between the solder resist dry film and the substrate.

In this embodiment, when the thickness of the substrate is 0.4mm or more, the pre-treatment for solder resist may include pickling, plate grinding, sand blasting, water washing, and dry plate (dry substrate) treatment.

Among them, the substrate may be acid-washed with sulfuric acid. The acid washing concentration may be 3 to 5wt%. If the pickling concentration is lower than 3wt%, the copper surface can not remove oxides, and the bonding force between the solder resist dry film and the copper surface is influenced; if the pickling concentration is higher than 5wt%, the copper surface has slight copper biting and the cost is increased. The pickling pressure can be 2.0 plus or minus 0.5Kg/cm ² . The pressure of the overflow water washing can be 1.5 plus or minus 0.5Kg/cm ² . Here, the pickling concentration refers to the mass percentage concentration of the pickling solution (e.g., sulfuric acid).

Wherein the amount of the medium coarsening undercut may be 0.5 to 1.5 μm. If the medium coarsening bite amount is less than 0.5 mu m, the roughness of the copper surface is not enough, and the bonding force between the solder resist dry film and the copper surface is influenced; if the etching amount of the medium coarsening is more than 1.5 mu m, the etching of the copper surface is too large, and the copper thickness is thinned. The term "roughening/galling amount" as used herein means the amount of galling caused by pickling.

The width of the grinding crack generated by the grinding plate can be 10-15 mm. If the width of the grinding mark is less than 10mm, the copper surface is not completely treated or the roughness is not enough, so that the binding force between the solder-resisting dry film and the copper surface is influenced; the loss of the copper surface with the grinding crack width higher than 15mm is overlarge, so that the copper thickness is thinned.

The sand blasting refers to that the substrate is sent into a sand blasting machine, the volume percentage concentration of carborundum sprayed by the sand blasting machine can be 15-25%, and the sand blasting pressure can be 2.0 +/-0.5 Kg/cm ² So as to form coherent and orderly arranged jet marks on the surface of the substrate.

The water washing treatment may include sewage flushing, first pressure water washing, ultrasonic immersion washing, high-pressure swing water washing, second pressure water washing, HF water washing (ultrasonic water washing), and third pressure water washing. Wherein the washing pressure of the flushing water can be 1-1.5 Kg/cm ² The HF washing pressure may be 2.0 + -0.5 Kg/cm ² The pressure of the three times of pressurized water washing can be 2.0 plus or minus 0.5Kg/cm ² The high-pressure swing water washing can be 10-15 Kg/cm ² . The washing pressure refers to the spray pressure sprayed through the spray pipe. According to the invention, through different washing operations and control of washing pressure parameters, the substrate can be more effectively washed, and the clamping is prevented.

The drying treatment can comprise suction drying, strong wind drying, hot wind drying and cold wind drying. Wherein, the water absorption sponge can be adopted for absorbing and drying. The blowing pressure of strong wind can be 8-15 Kpa. The drying temperature can be 95 +/-5 ℃. Through the different operations of weathering and the control of the operational parameters of weathering, can dry the steam in the hole and on the board surface, guarantee the drying of the board surface, improve the copper surface and hinder the cohesion of welding the dry film.

S2, preparing a solder resist dry film.

Hinder the dry film and can make the figure of line width 0.1mm, can both obtain edge vertically lines at dry film thickness within range, guarantee the lines progress, hinder the thickness of dry film and constitute the base plate temperature, discontinuity when avoiding forming images, the reliability is high, is convenient for master, uses to hinder and to hinder the dry film and can simplify the seal plate-making manufacturing procedure greatly, is favorable to realizing mechanizedly and automatic.

The dry film thickness of the solder resist may be 20 to 60 μm. If the dry solder resist thickness is less than 20 μm, it may result in no coverage of the wiring, and if the dry solder resist thickness exceeds 60 μm, it may result in excessive dry solder resist flow. The dry film thickness of the solder resist may be 30 to 50 μm. The thickness of the solder resist dry film may also be 25 to 40 μm.

Alternatively, the dry film for solder resist may be composed of three parts of a polyethylene protective film, a photoresist film and a carrier polyester film, which have thicknesses of 20 to 30 μm, 10 to 100 μm and 20 to 30 μm, respectively, for example, thicknesses of 25 μm, 80 μm and 25 μm, respectively. The polyester film is a carrier for supporting the photosensitive adhesive layer, and is coated to form a film. The polyester film is removed after exposure and before development, and prevents oxygen from diffusing into the resist layer during exposure, destroying radicals, and causing a decrease in sensitivity. The polyethylene protective film is a protective film covering the photosensitive adhesive layer, so that dirt such as dust is prevented from adhering to a dry film, and mutual adhesion between each layer of resist film is avoided when the film is rolled. The photoresist film is the main body of the dry film and can be a negative photosensitive material.

In this embodiment, the main component of the dry film solder resist may be acrylic resin, which is a novel material to replace the existing solder resist process ink.

In an embodiment, the main component of the dry film solder resist may include one or more of a photopolymerizable monomer, a photoinitiator, an adhesive, a plasticizer, a tackifier, a thermal polymerization inhibitor, a colorant, and a solvent. The solder resist dry film has the characteristics of high resolution, high adhesive force, small development side erosion and the like, and the minimum analyzable solder resist bridge width is 2mil.

And S3, vacuum film pasting.

Specifically, the dry film solder resist may be applied to the substrate by a vacuum laminator in a vacuum state.

Wherein, when the vacuum pressure resistance welds the dry film, the temperature of the laminator can be 60-70 ℃. If the control temperature is lower than 60 ℃, the film is not firm, the binding force is poor, and if the control temperature is higher than 70 ℃, the dry film is excessively crosslinked, the binding force is also influenced. Alternatively, the control temperature may be 61 to 68 ℃.

The vacuum time may be 15 to 30 seconds. If the vacuum time is less than 15s, bubbles can be generated between the dry film and the copper surface; if the vacuum time exceeds 30 seconds, cost and efficiency are wasted because the vacuum has been reached. Here, the film pasting is completed in a vacuum chamber, and the vacuum time refers to the time of vacuumizing before the film pasting so as to enable the vacuum degree in the vacuum chamber to reach the requirement, and then the film pasting is performed.

The film-attaching time may be 15 seconds or more, for example, 15 to 30 seconds. If the film sticking time is less than 15s, the film sticking is not firm, and the bonding force is poor; if the film pasting time exceeds 30s, the dry film can be excessively crosslinked, and the dry film becomes thin.

The film sticking pressure can be 0.3-0.8 Kg/cm ² . If the film sticking pressure is lower than 0.3Kg/cm ² The sticking film is not firm, and the binding force is poor; if the pressure of the film is more than 0.8Kg/cm ² Dry film access holes can result. The film sticking pressure can be 0.4-0.7 Kg/cm ² . The film sticking pressure can be 0.5-0.6 Kg/cm ² 。

The thickness of the film copper can be 18-105 μm. The film copper thickness refers to the thickness of the substrate copper which can be processed by the solder resist dry film, and if the film copper thickness exceeds 105 μm, the film copper thickness exceeds the dry film processing capacity and cannot cover the circuit. The thickness of the film copper can be 20-95 μm. The thickness of the film copper can be 40-55 μm.

And S4, exposing.

Specifically, the solder resist film is used to expose the area to be soldered on the surface of the substrate where the solder resist dry film is completed in step S3. And protecting the area which does not need to be welded, completely covering the solder mask, and firmly adhering the solder mask dry film in the unexposed area to the substrate to form a layer of solder mask curing film.

Wherein, the exposure stage number can be 9-11 stages, and the exposure energy can be 200-600 mj. If the exposure parameter is lower than the lower limit, poor exposure can occur, the small part of the bonding pad cannot be formed, and if the exposure parameter exceeds the upper limit, overexposure is performed, so that incomplete development is caused. The number of exposure steps may be 10 steps, and the exposure energy may be 300 to 500mj.

And S5, developing.

Specifically, the exposed portion is subjected to an alkaline solution developing treatment. The alkaline solution may be Na ₂ CO ₃ Potassium carbonate (K) ₂ CO ₃ ) And the like.

In this embodiment, the alkaline solution may be Na ₂ CO ₃ ，Na ₂ CO ₃ Can be in the mass percentage concentration of0.8 to 1.2 percent. If Na is present ₂ CO ₃ Concentrations below 0.8% may result in incomplete development if Na is present ₂ CO ₃ Concentrations in excess of 1.2% can lead to over-development, which can create quality problems.

In this embodiment, the concentration of the alkaline solution may be 0.9 to 1.1% by mass, for example, 1.0%. The pH value of the alkaline solution is more than or equal to 10.5, and the pH value is less than 10.5, so that the developing effect is influenced. The pH value is more than or equal to 11.

In the present embodiment, the developing time may be 60 to 100 seconds. If the developing time is out of this range, the development quality is deteriorated. The development time may be 70 to 90s, for example, 80s.

S6, curing.

And curing the developed substrate.

The temperature of the curing treatment is controlled to be about 150 to 160 ℃, for example, 152 to 158 ℃. The time of curing treatment is controlled to be 60-70 min. If the temperature and time of the curing treatment exceed the lower limits, the curing cannot be completely carried out, and the dry film is easy to fall off; if the temperature and time of the curing treatment exceed the upper limits, the dry film discolors and becomes brittle.

The solder resistance bridge is formed on the printed board, the minimum width of the solder resistance bridge can reach 2 mils, and for example, the width of the solder resistance bridge can be 2 mils to 3.9 mils. Through a thermal stress test, the problems of dry film falling and bridge falling are solved, and the yield is improved by 10% from 88% and reaches 98%.

Although the present invention has been described above in connection with exemplary embodiments, it will be apparent to those skilled in the art that various modifications and changes may be made to the exemplary embodiments of the present invention without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for spray printing a two-dimensional code on a printed board is characterized by comprising the following steps:

determining spray printing coordinates on a printed board;

determining ink-jet data according to the provided two-dimensional code information, wherein the ink-jet data comprises at least one of data matrix information and a serial number and a two-dimensional code encoding format, and the data matrix information comprises a client code and a periodic code;

based on ink-jet data, ink-jet equipment is used for carrying out jet printing for at least 2 times at a jet printing coordinate position on a printing plate to jet print a two-dimensional code, the ink-jet speed is 400-600 mm/s, and the ink-jet flow is 20-40 ml/min, wherein the ink-jet equipment is provided with 2-8 nozzles, an ink path part of the ink-jet equipment comprises a negative pressure control mechanism, a first-stage ink box, a first-stage filtering mechanism, a power mechanism, a second-stage ink box and a second-stage filtering mechanism, wherein the first-stage ink box and the second-stage ink box are sequentially connected in an ink flowing mode and are finally connected to the nozzles; a pressure sensor is arranged in the secondary ink box to realize accurate control of the pressure intensity, and the pressure sensor is connected with a negative pressure control mechanism;

drying the two-dimensional code subjected to jet printing;

the ink path component of the ink jet equipment also comprises a first heating mechanism and a second heating mechanism, the first heating mechanism can heat the ink in the first-level ink box, and the second heating mechanism can heat the ink in the second-level ink box;

the method further comprises the steps of: after jet printing is finished, baking the two-dimensional code and the solder resist ink together;

the length and the width of the two-dimensional code are at least 5mm, the minimum width of the characters is 3mil, and the minimum height of the characters is 20mil; the thickness of the ink of the two-dimensional code is 20-40 mu m;

the format of the serial number comprises [ PCS ], [ PNL ], [ PCS ] [ PNL ] or [ PNL ] [ PCS ], wherein PNL is the working size of the printed board processing process, and PCS is the delivery size;

the ink-jet equipment also comprises a matched auxiliary mechanism, wherein the auxiliary mechanism comprises a mechanical arm and an automatic plate turnover machine, the mechanical arm can finish feeding and discharging, and the automatic plate turnover machine can turn over the printed board to finish two-side jet printing;

the complementary unit still includes visual detection mechanism, and wherein, visual detection mechanism is including the unit of shooing, the control unit and polish the unit, and wherein, the unit of shooing can gather the whole image of two-dimensional code, and the control unit can compare this whole image and image template to judge whether qualified according to the comparison result two-dimensional code appearance, qualified includes: the size and the dimension of the whole image are qualified, the appearance of the whole image is qualified, and the thickness of the two-dimensional code line is qualified; the lighting unit can enable the photographing unit to acquire a proper image, the lighting unit is provided with a lamp strip with a plurality of light-emitting pieces, each light-emitting piece projects light to the two-dimensional code at an incompletely same angle, and the shape of the lamp strip is consistent with the shape of the two-dimensional code;

the viscosity of the ink used by the ink jet equipment is 22-26 cps at room temperature, the surface tension is 20-40 mN/m, and the average particle diameter is 220-260 nm.

2. The method of inkjet printing a two-dimensional code on a printed board according to claim 1, wherein after the drying process, the method further comprises at least one of an image detection and a reading test, wherein,

the image detection includes: the method comprises the following steps of collecting an integral image of the two-dimensional code, comparing the integral image with an image template, and judging whether the appearance of the two-dimensional code is qualified according to a comparison result, wherein the qualification comprises the following steps: the size and the dimension of the whole image are qualified, the appearance of the whole image is qualified, and the thickness of the two-dimensional code line is qualified;

the read test includes: the two-dimensional code is read to determine whether correct information can be read from the two-dimensional code.

3. The method for jet printing the two-dimensional code on the printed board according to claim 1, wherein the character effect of the jet printed two-dimensional code is a positive film.

4. The method for spray-printing the two-dimensional code on the printed board according to claim 1, wherein the drying temperature is 130-170 ℃ and the drying time is 40-80 min.

5. The method for jet printing the two-dimensional code on the printed board according to claim 1, wherein the step of determining the ink-jet data comprises:

processing the provided two-dimensional code information by using a script Genesis-V8 to determine the ink-jet data.

6. The method for spray printing the two-dimensional code on the printed board according to claim 1, wherein the printed board is a printed circuit board comprising a solder resist bridge made of a dry film solder resist, and the printed circuit board is prepared by the following method:

preparing a substrate, wherein the substrate comprises a metal layer and an insulating layer;

preparing a solder resist dry film;

vacuum film pasting: vacuum-attaching the solder-resisting dry film on the substrate at the temperature of 60-70 ℃, wherein the vacuum time is more than 15s, and the film attaching time is 15-30 s;

exposing the area needing welding in the surface area of the substrate after film pasting in an exposure and development mode to expose the metal layer; curing the developed substrate, and forming a solder mask bridge on the obtained printed board;

the step of preparing the substrate comprises the steps of carrying out resistance welding pretreatment on the substrate, wherein a grinding mark with the width of 10-15 mm is formed on the substrate after the resistance welding pretreatment, and the medium coarsening and biting amount is 0.5-1.5 mu m;

in the step of vacuum film pasting, the film pasting pressure is 0.3-0.8 Kg/cm ² The thickness of the film copper is 18-105 μm;

in the exposure step, the exposure level is 9-11 levels, and the exposure energy is 200-600 mj;

carrying out development treatment on the exposed part by adopting an alkaline solution, wherein the mass percentage concentration of the alkaline solution is 0.8-1.2%, the pH value of the alkaline solution is more than or equal to 10.5, and the development time is 60-100 s;

in the curing step, the temperature is controlled to be 150-160 ℃, and the curing time is 60-70 min;

the dry film solder resist consists of a polyethylene protective film, a photoresist film and a carrier polyester film, wherein the thickness of the polyethylene protective film is 20-30 mu m, the thickness of the photoresist film is 10-100 mu m, and the thickness of the carrier polyester film is 20-30 mu m.