A method for replacing dry film in an automated device

Abstract

The present invention discloses a method for replacing dry film in an automated device, comprising the following steps: calculating the downtime t of the board feeder and setting the time t in the main machine of the film laminator; installing an alarm device on the film laminator to sense the remaining film thickness of the dry film on the film laminator; when the alarm device senses that the dry film thickness on the film laminator is less than or equal to the required remaining film thickness of the dry film, the alarm device emits an alarm signal and transmits it to the board feeder, and the board feeder stops feeding boards after receiving the alarm signal; after the production boards on the conveyor belt between the board feeder and the film laminator are completely laminated, the film laminator stops, and the operator replaces the new dry film roll onto the film laminator; after the downtime of the board feeder reaches the preset time t, the board feeder starts to automatically feed boards. The method of the present invention does not require manual board feeding and manual judgment of the remaining film thickness of the dry film, reduces the dependence on labor and waste of dry film tailings, can save time and thus improve production efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of printed circuit board manufacturing, and specifically relates to a method for replacing dry film of an automated device. Background Art

[0002] As a carrier for electronic components, a circuit board is an essential and important electronic component of an electronic device. Before exposure, the circuit board needs to be treated with dry film lamination. During the lamination process, the circuit board needs to be fed into a laminator for lamination; moreover, when the dry film is used up, the film roll needs to be replaced in a timely manner.

[0003] However, at present, some of the board feeding is completed manually. Due to the long waiting time, the film is likely to fall off the board surface and open circuit gaps are likely to occur, resulting in scrap; moreover, the timing of dry film replacement is judged manually by visual inspection, lacking a unified judgment standard, and it is easy to have the problem of waste of dry film tailings; after the dry film replacement is completed, it is also necessary to manually notify the pretreatment process to feed the board; the above operations are time-consuming and laborious, and there is a lot of material waste, resulting in low production efficiency and high production cost of the circuit board. Summary of the Invention

[0004] In view of the above existing technical defects, the present invention provides a method for replacing dry film of an automated device. By calculating the downtime of the board feeder and calculating the remaining film thickness of the dry film to determine the installation position and moving distance of the alarm device on the laminator, automatic and precise monitoring of the remaining film thickness of the dry film is achieved. This method does not require manual board feeding and judgment of the remaining film thickness of the dry film, reduces the dependence on manual labor and waste of dry film tailings, and can save time and thus improve production efficiency.

[0005] To solve the above technical problems, the present invention provides a method for replacing dry film of an automated device, including the following steps:

[0006] S1. Calculate the downtime t of the board feeder and set the time t in the main machine of the laminator;

[0007] S2. Install an alarm device on the laminator to sense the remaining film thickness of the dry film on the laminator;

[0008] S3. When the alarm device senses that the dry film thickness on the laminator is less than or equal to the required remaining film thickness of the dry film, the alarm device sends an alarm signal and transmits it to the board feeder. After receiving the alarm signal, the board feeder stops feeding the board;

[0009] S4. After the production board on the conveyor belt between the board feeder and the laminator is laminated, the laminator stops, and the operator replaces the new dry film roll on the laminator;

[0010] S5. After the downtime of the board feeder reaches the preset time t, the board feeder starts to automatically feed the board.

[0011] Further, the downtime t of the plate placing machine is t = t1 + t2 - t3, where the maximum number of production plates that can be placed simultaneously on the conveyor belt between the plate placing machine and the film laminating machine is N, and N is a positive integer ≥ 1. t1 is the time required for the N production plates placed on the conveyor belt after the plate placing machine stops to be sequentially conveyed to the film laminating machine and have the dry film pasted. t2 is the film changing time, and t3 is the time required for the production plate to be released by the plate placing machine and reach in front of the film laminating machine.

[0012] Further, the film changing time includes the time for manually replacing the dry film roll and the time for cleaning the film laminating machine.

[0013] Further, the calculation method for the remaining film thickness of the dry film is: the thickness formed by winding the dry film length required for at least N + 1 production plates to be pasted with dry film on only one side around the core tube.

[0014] Further, the alarm device can be movably installed on the film laminating machine to adjust the position of the alarm device according to the required remaining film thickness of the dry film.

[0015] Further, the alarm device includes an infrared emitter located above the dry film roll and an infrared receiver located below the dry film roll.

[0016] Further, the infrared emitter and the infrared receiver are symmetrically arranged directly above and directly below the required remaining film thickness of the dry film, and the infrared rays emitted by the infrared emitter are just tangent to the position of the required remaining film thickness of the dry film; when the dry film thickness on the film laminating machine is less than or equal to the required remaining film thickness of the dry film, the infrared rays emitted by the infrared emitter pass through the film roll and are received by the infrared receiver, and an alarm signal is sent. After receiving the alarm signal, the plate placing machine stops placing plates.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The method of the present invention first calculates the downtime of the plate placing machine and sets the time t in the main machine of the film laminating machine. Then, an alarm device is installed on the film laminating machine to sense the remaining film thickness of the dry film to obtain the shutdown timing of the plate placing machine. Next, the remaining film thickness of the dry film is calculated to determine the installation position of the alarm device for accurately monitoring the remaining film thickness of the dry film. The operator can replace the dry film roll within the downtime of the plate placing machine. When the downtime of the plate placing machine reaches the time preset in the main machine of the film laminating machine, the next round of plate placing will be automatically carried out. This method does not require manual plate placing and manual visual judgment of the remaining film thickness of the dry film, reduces the dependence on labor and waste of dry film tail materials, has reasonable time connection, can save time and thus improve production efficiency, avoids the film falling off the plate surface and open circuit gaps caused by long waiting time during manual plate placing, controls the scrap rate within 0.5%, and ensures product quality. Specific embodiments

[0019] To better understand the technical content of the present invention, the present invention will be further introduced and described below in conjunction with specific embodiments; obviously, the following described embodiments are only a part of the embodiments of the present invention, rather than all embodiments; based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0020] For those skilled in the art, the features, beneficial effects and advantages of the present invention will become obvious by reading the content disclosed in this specification.

[0021] Embodiment

[0022] A method for manufacturing a circuit board shown in this embodiment, which includes a method for replacing dry film by an automated device, specifically including the following processing procedures:

[0023] (1) Pretreat the surface of the production board according to the existing pretreatment technology to remove the oxides on the surface.

[0024] (2) The production board that has undergone the pretreatment process in step (1) is sent from the board feeder to the film laminator for dry film lamination. An infrared emitter is installed on the film laminator to monitor the remaining film thickness of the dry film. When the dry film is about to run out, the operator is reminded in time to replace the dry film roll. Monitoring the remaining film thickness of the dry film specifically includes the following steps:

[0025] a. First, calculate the downtime t of the board feeder. The downtime t of the board feeder = the time t1 required for N production boards placed on the conveyor belt after the board feeder stops to be sequentially conveyed to the film laminator and the dry film is laminated + the film replacement time t2 - the time t3 required for the production board to be released by the board feeder and reach in front of the film laminator. Here, N production boards refer to the maximum number of production boards that can be placed simultaneously on the conveyor belt between the board feeder and the film laminator. In the actual production process, the length of the conveyor belt between the board feeder and the film laminator is 13 meters, the length of the production board is 725 mm, the board spacing is 15 mm, and the boards are fed horizontally. So, the conveyor belt between the board feeder and the film laminator can place 17 production boards. The production capacity of the full-automatic film laminator (Siwo Precision Machinery Co., Ltd., model FCM-30) is 5 pieces / minute. Therefore, the time t1 required for 17 production boards to be laminated with the first side of the dry film is 3.4 minutes; the time t2 for the operator to replace the new dry film roll and clean the film laminator is 6 minutes; the pretreatment speed is 4 m / minute. Therefore, the time t3 required for the production board to be released by the board feeder and reach in front of the film laminator is 3.25 minutes. From this, the downtime t of the board feeder is calculated to be 6.15 minutes. Then, set the downtime of the board feeder in the main machine of the film laminator to 6.15 minutes.

[0026] b. The alarm device includes an infrared emitter located directly above the dry film roll and an infrared receiver located directly below the dry film roll. The infrared rays emitted by the infrared emitter are tangent to the required dry film remaining thickness. Since there is a certain distance between the cylindrical dry film rod installed on the laminator and the board surface, when the laminator is working, the dry film is pulled from the cylindrical dry film rod and pasted on the production board. Therefore, at least the dry film required for N + 1 production boards with only one side pasted with dry film is needed to ensure that N production boards can be completely pasted with the first side of the dry film. Since the conveyor belt from the board loader to the laminator is 13 meters long and can hold 17 production boards, at this time, reserving the length of the dry film required for 20 production boards can ensure that 17 production boards can be completely pasted with dry film. That is, the calculation method for the dry film remaining thickness is as follows: for 20 production boards, each with a length of 725 mm, the total required length of the dry film remaining is 14.5 meters. The dry film roll passes through the cylindrical dry film rod on the laminator and is installed on the laminator. The radius of the core tube is 4 cm. Therefore, the 14.5-meter-long dry film can be wound into 58 circles on the core tube. The thickness of each layer of dry film is known to be 40 microns. Then the thickness of the 58-layer dry film stack on the core tube is 2.3 mm. This thickness is the dry film remaining thickness. In this embodiment, when a complete roll of dry film gradually thins during the laminating process, requiring the dry film remaining thickness to be 2.3 mm can ensure that 17 production boards are completely pasted with dry film while minimizing waste of the dry film tail. As the entire roll of dry film gradually thins during continuous laminating, when the infrared emitter cannot sense the dry film, that is, when the dry film thickness on the laminator is less than or equal to the required dry film remaining thickness, at this time, the infrared emitter emits an alarm signal and transmits it to the infrared receiver installed below the dry film rod on the laminator. The infrared rays emitted by the infrared emitter pass through the film roll and are received by the infrared receiver, and an alarm signal is sent. After receiving the alarm signal, the board loader stops loading boards; while the production boards that have already been released by the board loader will continue to be transported to the laminator for laminating.

[0027] c. After the last production board is laminated, the operator replaces the cylindrical dry film rod without dry film coverage, and then installs a cylindrical dry film rod with a new dry film roll on the laminator;

[0028] d. When the downtime of the board loader reaches the set time of 6.15 minutes, the board loader starts to automatically load boards without manual board feeding, and proceeds to the next round of laminating production boards.

[0029] (3) Use a fully automatic exposure machine to perform inner layer circuit exposure on the production board that has been pasted with dry film with 5 - 6 exposure scales (21 exposure scales), and form the inner layer circuit pattern after development; inner layer etching, etch the inner layer circuit of the core board after exposure and development, and the inner layer line width is measured to be 3 mil; inner layer AOI, then check for defects such as open circuits, short circuits, line gaps, and line pinholes in the inner layer circuit. Defective products are scrapped, and non-defective products proceed to the next process.

[0030] (4) Laminating: The brownification speed is based on the copper thickness of the base copper. The core board, prepreg, and outer copper foil are laminated in sequence as required, and then the laminated board is laminated under appropriate lamination conditions according to the Tg of the board material to form a production board.

[0031] (5) Drilling: According to the existing drilling technology, drilling processing is carried out on the production board according to the design requirements.

[0032] (6) Electroless copper plating: A thin layer of copper is deposited on the board surface and hole walls by electroless copper plating. The backlight test is at level 10, and the copper thickness in the holes is 0.5μm.

[0033] (7) Full-panel electroplating: Full-panel electroplating is carried out for 120 minutes at a current density of 18 ASF to thicken the hole copper and the copper layer on the board surface to the required thickness.

[0034] (8) Making outer-layer circuits (positive film process): Outer-layer pattern transfer. Using a fully automatic exposure machine and positive film circuit film, the outer-layer circuit exposure is completed with a 5 - 7-step exposure scale (21-step exposure scale). After development, the outer-layer circuit pattern is formed on the production board; Outer-layer pattern electroplating. Then, copper and tin are electroplated on the production board respectively. The electroplating parameters are set according to the required copper thickness. The copper electroplating is full-panel electroplating for 60 minutes at a current density of 1.8 ASD, and the tin electroplating is electroplating for 10 minutes at a current density of 1.2 ASD, with a tin thickness of 3 - 5μm; Then, stripping, etching, and tin stripping are carried out in sequence to etch the outer-layer circuit on the production board. The copper thickness of the outer-layer circuit is greater than or equal to 70μm; Outer-layer AOI. Using an automatic optical inspection system, by comparing with the CAM data, it is detected whether there are defects such as open circuits, gaps, incomplete etching, and short circuits in the outer-layer circuit.

[0035] (9) Solder mask and silk-screen printing of characters: After silk-screen printing solder mask ink on the surface of the production board, and then through pre-curing, exposure, development, and thermal curing treatments in sequence, the solder mask ink is cured into a solder mask layer; Specifically, solder mask ink is applied on the TOP surface, and the character "UL mark" is added on the TOP surface, so as to coat a protective layer on the circuits and substrates that do not need to be welded to prevent bridging between circuits during welding, provide a permanent electrical environment, and resist chemical corrosion, and at the same time play a role in beautifying the appearance.

[0036] (10) Surface treatment (immersion nickel and gold): On the copper surface of the pads at the solder mask openings, a nickel layer and a gold layer with a certain required thickness are evenly deposited through chemical principles. The nickel layer thickness is: 3 - 5μm; The gold layer thickness is: 0.05 - 0.1μm.

[0037] (11) Electrical testing: Test the electrical conduction performance of the finished board. The test method used for this board is: flying probe testing.

[0038] (12) Forming: According to the existing technology and design requirements, mill the outer shape with a tolerance of + / -0.05 mm for the outer shape to obtain a resin plug-hole board.

[0039] (13) FQC: Inspect the appearance of the circuit board according to the customer acceptance standard and our company's inspection standard. Repair any defects in a timely manner to ensure excellent quality control for the customer.

[0040] (14) FQA: Re-inspect whether the appearance, hole copper thickness, dielectric layer thickness, green oil thickness, inner layer copper thickness, etc. of the circuit board meet the customer's requirements.

[0041] (15) Packaging: Seal-pack the circuit board according to the packaging method and quantity required by the customer, place desiccants and humidity cards, and then ship the goods.

[0042] For the traditional manual visual method, after changing the dry film, it is necessary to notify the pretreatment to release the board. Since there is no unified judgment standard for manual visual inspection and the visual method is not precise enough, usually when the dry film is about to run out, the waste of the dry film tail of 17 production boards is 2 meters. Moreover, the production board needs to be manually taken out from the board feeder and transported to the laminator. Due to the long waiting time, it is easy to cause film dropping and open circuit notch scrapping, and the scrapping rate of 17 production boards is 2%. While using the method of the present invention to accurately calculate the remaining film thickness of the dry film and using an alarm device for monitoring and alarming, the waste of the dry film tail of each roll of dry film is at most 1 meter. In this embodiment, the dry film is changed 10 times a day. Since the dry film needs to be attached to both sides of the production board, and the method of the present invention is applied in the process of attaching the first side of the dry film. By only sensing and monitoring the process of attaching the dry film to the first side of the production board, the waste of the tail material caused by attaching the dry film to the first side and the second side can be avoided at the same time. Then, 10*2*30*(2 - 1)

[0043] = 600 m can be saved per month; the method of the present invention accurately calculates the downtime of the board feeder, making the time connection reasonable, eliminating the need for manual board feeding, the scrapping rate can be controlled within 0.5%, and about 3 minutes can be saved each time the dry film is changed, saving 900 minutes per month, and the monthly production capacity of a single line can be increased by 4500 - 5000 PNL.

[0044] The technical solutions provided by the embodiments of the present invention have been introduced in detail above. Specific examples are used in this article to elaborate on the principles and implementation manners of the embodiments of the present invention. The descriptions of the above embodiments are only applicable to help understand the principles of the embodiments of the present invention; at the same time, for those of ordinary skill in the art, based on the embodiments of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. An automated equipment dry film replacement method, characterized in that, It includes the following steps: S1. Calculate the downtime t of the board feeder and set the time t in the main unit of the film laminator; S2. Install an alarm device on the film laminator to sense the dry film remaining thickness on the film laminator; S3. When the alarm device senses that the dry film thickness on the film laminator is less than or equal to the required dry film remaining thickness, the alarm device sends an alarm signal and transmits it to the board feeder. After receiving the alarm signal, the board feeder stops feeding boards; S4. After the production boards on the conveyor belt between the board feeder and the film laminator are completely laminated, the film laminator stops. The operator replaces the new dry film roll on the film laminator; S5. After the downtime of the board feeder reaches the preset time t, the board feeder starts to automatically feed boards; The downtime t of the board feeder = t1 + t2 - t3, where the maximum number of production boards that can be placed simultaneously on the conveyor belt between the board feeder and the film laminator is N, N is a positive integer ≥ 1, t1 is the time required for the N production boards placed on the conveyor belt after the board feeder stops to be sequentially conveyed to the film laminator and completely laminated with dry film, t2 is the film replacement time, and t3 is the time required for the production board to be discharged from the board feeder and reach in front of the film laminator; The film replacement time includes the time for manually replacing the dry film roll and the time for cleaning the film laminator; The calculation method of the dry film remaining thickness is: the thickness formed by winding the dry film length required for at least N + 1 production boards to be laminated on only one side around the core tube; 2. The automated equipment dry film replacement method according to claim 1, characterized in that, The alarm device can be movably installed on the film laminator to adjust the position of the alarm device according to the required dry film remaining thickness; 3. The automated equipment dry film replacement method according to claim 1, characterized in that, The alarm device includes an infrared emitter located above the dry film roll and an infrared receiver located below the dry film roll; 4. The automated equipment dry film replacement method according to claim 3, characterized in that, The infrared emitter and the infrared receiver are symmetrically arranged directly above and directly below the required dry film remaining thickness, and the infrared rays emitted by the infrared emitter are just tangent to the required dry film remaining thickness; when the dry film thickness on the film laminator is less than or equal to the required dry film remaining thickness, the infrared rays emitted by the infrared emitter pass through the film roll and are received by the infrared receiver, and an alarm signal is sent. After receiving the alarm signal, the board feeder stops feeding boards.