Circuit board production process

Abstract

The invention discloses a circuit board production process, which comprises the steps of process review, program production, material checking, baking, SMT (Surface Mount Technology) first piece manufacturing, SMT first piece inspection, SMT reflow soldering, QC (Quality Control) inspection, DIP (Dual In-line Package) first piece manufacturing, DIP first piece inspection, DIP production and testing, and is characterized in that through a fine production process, element placement is accurately controlled, baking and welding steps are optimized, and quality detection is enhanced. The purposes of improving the production efficiency and ensuring the product quality and reliability are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic component manufacturing and relates to a circuit board production process. Background Art

[0002] With the rapid development of the electronics industry, circuit boards, as core components of electronic equipment, have a direct impact on the market competitiveness of products due to their production efficiency and quality. The existing circuit board production process has some shortcomings, such as the lack of systematic evaluation of the production process, which leads to waste of resources and low production efficiency; the automatic placement machine operation procedures are not flexible enough to adapt to the changing component layout, which affects the accuracy of component placement; the baking steps and reflow soldering temperature control are not precise, which can easily cause poor welding; in addition, the visual inspection and functional testing methods are not perfect, which makes it difficult to ensure the reliability of circuit boards. These problems limit the efficiency and quality of circuit board production. Summary of the invention

[0003] The purpose of the present invention is to propose a circuit board production process, which can improve production efficiency and ensure product quality and reliability through refined production processes, precise control of component placement, optimization of baking and welding steps, and enhanced quality inspection.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A circuit board production process comprises the following steps:

[0006] Process review, to evaluate the feasibility of the production process, including the review of materials, equipment, personnel and environmental conditions;

[0007] Programming: Based on the PCB component layout and orientation information, write the operating program of the automatic placement machine to guide the placement machine to accurately place the electronic components at the predetermined position on the PCB;

[0008] Check and prepare materials and components required for production according to the bill of materials and production plan;

[0009] A bake step uses a moisture sensitivity bake test fixture to bake moisture-sensitive materials and components in a controlled environment to remove moisture;

[0010] The first SMT patch is produced by printing solder paste on the pads of the PCB, and using an automatic placement machine to place electronic components on the solder paste to produce the first sample;

[0011] SMT first piece inspection: visual inspection and X-ray inspection of SMT first piece samples to check PCB solder joints and component placement;

[0012] SMT patch reflow soldering, print solder paste on the pads of PCB, use automatic placement machine to place electronic components on the solder paste, and then pass through the reflow oven for soldering;

[0013] QC inspection, visual inspection and X-ray inspection, inspection of PCB solder joints and component placement

[0014] DIP first piece production, inserting components into pre-drilled holes in PCB and soldering to produce the first sample;

[0015] DIP first article inspection: visual inspection and X-ray inspection of DIP first article samples to check PCB solder joints and component placement;

[0016] DIP production, based on the samples made from the first DIP piece, subsequent production is carried out, components are inserted into the pre-drilled holes of the PCB and soldered;

[0017] The test steps include performing functional tests and performance tests on the PCB after SMT to verify the electrical performance of the circuit board.

[0018] Furthermore, before the SMT patch reflow soldering, it also includes steel mesh production;

[0019] Steel mesh production, according to the pad design file of the printed circuit board, uses laser cutting technology to carve a steel mesh with a predetermined pattern on the stainless steel plate for solder paste printing.

[0020] Furthermore, in the steel mesh production step, the thickness of the steel mesh ranges from 0.12 mm to 0.20 mm.

[0021] Furthermore, in the program making step, the operating program of the automatic placement machine includes the settings of component placement speed, placement pressure and rotation angle.

[0022] Furthermore, in the baking step, the temperature range of the moisture sensitivity baking test fixture is between 125° C. and 150° C.

[0023] Furthermore, in the SMT patch reflow soldering, the preheating temperature of the reflow soldering furnace ranges from 90°C to 120°C, the thermal activation temperature ranges from 150°C to 180°C, and the reflow temperature ranges from 210°C to 230°C.

[0024] Furthermore, in the production of the first DIP piece, wave soldering or selective soldering is used for soldering.

[0025] Furthermore, the visual inspection includes inspection of component placement, welding quality and pin bending.

[0026] Furthermore, in the testing steps, the functional test includes performing voltage testing, current testing and signal integrity testing on the circuit board.

[0027] Furthermore, the testing step is followed by a completion step and a warehousing step;

[0028] Finishing step, final testing and adjustment of the products that have completed all production and inspection processes, and then packaging;

[0029] In the warehousing step, the packaged products undergo a final quality review, check the quantity, inspect the packaging, determine the storage location, and update the inventory system.

[0030] Beneficial effects of the present invention: The present invention significantly improves production efficiency and product quality through a comprehensive improvement of the circuit board production process. Process review ensures the feasibility of the production process and reduces resource waste. The precise automatic placement machine operation procedure improves the accuracy of component placement and reduces the defect rate. The controlled baking step effectively removes moisture and enhances the reliability of materials and finished products. Precise temperature control and optimized welding steps ensure welding quality and reduce poor welding. Comprehensive visual inspection and functional testing improve the reliability of circuit boards. Overall, the present invention achieves the purpose of improving production efficiency and ensuring product quality and reliability by optimizing each production link. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the structure of the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. It should be understood that the present application is not limited to the example embodiments disclosed herein. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0033] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0034] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0035] In the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] The present invention provides Figure 1 In an embodiment of the present invention, a circuit board production process includes the following steps:

[0037] Process review is to evaluate the feasibility of the production process, which includes the review of materials, equipment, personnel and environmental conditions; for example, it is to evaluate whether the specifications of the materials meet the requirements of the circuit board, whether the equipment is calibrated and maintained, whether the personnel are trained, and whether the environmental conditions (such as temperature and humidity) are controlled within the appropriate range.

[0038] Program making: According to the PCB component layout and direction information, write the operating program of the automatic placement machine to guide the placement machine to accurately place the electronic components at the predetermined position of the PCB; for example, for a PCB with a complex component layout, write a program to guide the placement machine to accurately place the electronic components at the predetermined position with a placement speed of 0.2 seconds, a placement pressure of 200 grams, and a rotation angle of 0 degrees.

[0039] Check materials. According to the bill of materials and production plan, check and prepare the materials and components required for production; for example, check the quantity and model of components such as resistors, capacitors, IC chips, etc. to ensure that they are consistent with the BOM.

[0040] A bake step uses a moisture sensitivity bake test fixture to bake moisture-sensitive materials and components in a controlled environment to remove moisture;

[0041] The first SMT patch is produced by printing solder paste on the pads of the PCB, and using an automatic placement machine to place electronic components on the solder paste to produce the first sample;

[0042] SMT first piece inspection: visual inspection and X-ray inspection of SMT first piece samples to check PCB solder joints and component placement;

[0043] SMT patch reflow, according to the first sample made by the SMT patch, the solder paste is printed on the pad of the PCB, the electronic components are placed on the solder paste using an automatic placement machine, and then soldered through a reflow oven;

[0044] QC inspection, visual inspection and X-ray inspection, inspection of PCB solder joints and component placement

[0045] DIP first piece production, inserting components into pre-drilled holes in PCB and soldering to produce the first sample;

[0046] DIP first article inspection: visual inspection and X-ray inspection of DIP first article samples to check PCB solder joints and component placement;

[0047] DIP production, based on the samples made from the first DIP piece, subsequent production is carried out, components are inserted into the pre-drilled holes of the PCB and soldered;

[0048] The test steps include performing functional tests and performance tests on the PCB after SMT to verify the electrical performance of the circuit board.

[0049] Specifically, the present invention achieves improved feasibility and stability of the production process and reduces the risk of material waste and production interruption, because process review ensures the suitability of materials, equipment, personnel and environmental conditions. Accurate automatic placement machine operating procedures improve the accuracy of component placement and reduce soldering defects, which is achieved by accurately setting the placement speed, pressure and rotation angle according to the properties of the components and the PCB layout. The baking step effectively removes moisture and improves the stability of the material and the reliability of the final product, because the baking process in a controlled environment ensures proper handling of moisture-sensitive materials. The temperature control of the reflow oven is precise, ensuring the quality of soldering, which is achieved by setting precise preheating, heat activation and reflow temperature ranges. Complete visual inspection and functional testing methods ensure the reliability and performance of the circuit board, because these inspection steps can promptly detect and correct problems in the component placement and soldering process.

[0050] More specifically, chip electronic components include chip resistors, chip capacitors, chip inductors, surface mount integrated circuits (ICs), etc. Chip resistors are miniaturized resistors, usually in a mounted form. Chip capacitors are miniaturized capacitors used for filtering, decoupling, etc. Chip inductors are miniaturized inductors used for signal filtering and electromagnetic compatibility. Surface mount integrated circuits (ICs) include various logic chips, memories, microprocessors, etc.

[0051] D IP electronic components include D IP integrated circuits, D IP transistors, D IP capacitors, D IP resistors and other electronic components with pins. D IP integrated circuits are old-fashioned microprocessors and memory chips. D IP transistors are direct-insertion bipolar transistors (BJT) or field-effect transistors (FET). D IP capacitors and D IP resistors have pins and can be fixed on the PCB by insertion and welding.

[0052] Before the SMT patch reflow soldering, it also includes steel mesh production;

[0053] Steel mesh production, according to the pad design file of the printed circuit board, uses laser cutting technology to carve a steel mesh with a predetermined pattern on the stainless steel plate for solder paste printing.

[0054] Design the stencil pattern according to the design requirements. Consider the shape, size and position of the openings of the stencil during the design to ensure that it matches the pad design exactly. During the design process, stainless steel plates between 0.06mm and 0.20mm are usually selected to meet the needs of different pads. Start the laser cutting machine and cut on the stainless steel plate according to the designed stencil pattern. The laser cutting machine will move precisely along the design path to cut out the required stencil shape. After the cutting is completed, the stencil is visually inspected to ensure that all openings are accurately cut according to the design file without burrs or other defects. Perform solder paste printing tests on the actual SMT production line. Use the stencil to print solder paste on the PCB and check the printing quality, including the uniformity and accuracy of the distribution of the solder paste. Make necessary adjustments to the stencil based on the test results. If problems are found in solder paste printing, such as bridging or missed printing, it may be necessary to modify the stencil opening design or adjust the laser cutting parameters.

[0055] In the steel mesh production step, the thickness of the steel mesh ranges from 0.06 mm to 0.20 mm. The thickness range of the steel mesh is determined according to the results of the pad design analysis. For example, for fine pitch pads, a steel mesh of 0.06 mm to 0.12 mm is selected; for standard pitch pads, a steel mesh of 0.15 mm to 0.20 mm is selected.

[0056] In the program making step, the operation program of the automatic placement machine includes the settings of component placement speed, placement pressure and rotation angle.

[0057] Collect detailed properties of all electronic components to be placed, including component type, size, weight, shape, and any special positioning requirements. Determine the best placement strategy for each component based on the properties of the component and the layout of the PCB. This includes deciding the placement speed, pressure, and rotation angle. For components of standard size and weight, set a medium placement speed to ensure efficiency and accuracy. For components of smaller size or lighter weight, reduce the placement speed to prevent the components from shifting during placement. Adjust the placement pressure based on the fragility of the component and the bearing capacity of the PCB. For fragile components, use lower pressure; for standard components, use medium pressure. For directional components such as polar capacitors and inductors, set a precise rotation angle to ensure the correct direction of the component. Ensure the accuracy and consistency of the automatic placement machine when placing electronic components, thereby improving production efficiency and product quality. In addition, this approach also improves the flexibility of the production line, enabling it to adapt to a variety of components of different types and sizes.

[0058] More specifically, the exact parameter settings depend on the model of the placement machine and the characteristics of the components. Here are some example parameters:

[0059] Electronic component placement speed, set between 0.06 seconds and 0.5 seconds, depending on component type and machine capabilities.

[0060] Place pressure, setting range is 0.2-0.8kgf, depending on the weight and fragility of the component.

[0061] Rotation angle, the angle range is between 0 degrees and 270 degrees.

[0062] In the baking step, the temperature range of the moisture sensitivity baking test fixture is between 120°C and 150°C. Classify and evaluate the moisture sensitivity of all materials and components that are about to enter the production line to determine their moisture levels and baking requirements. Select the appropriate baking temperature based on the moisture sensitivity level of the material. For highly moisture-sensitive materials, select a lower temperature (such as 120°C); for moderately moisture-sensitive materials, select a higher temperature (such as 150°C). This precisely controlled baking step ensures that moisture-sensitive materials and components are effectively baked in a controlled environment to remove moisture while avoiding damage to the material due to excessively high temperatures. This improves the stability of the material and the reliability of the final product.

[0063] In the SMT patch reflow, the preheating temperature of the reflow oven ranges from 90°C to 120°C, the thermal activation temperature ranges from 150°C to 180°C, and the reflow temperature ranges from 230°C to 255°C. The preheating temperature of the reflow oven is set between 90°C and 120°C. The purpose of preheating is to activate the flux in the solder paste, remove moisture from the solder paste and PCB, and avoid thermal shock. The thermal activation temperature is set between 150°C and 180°C. This step is to ensure that the flux in the solder paste can be fully activated, remove oxides on the PCB and component pins, and set the reflow temperature between 230°C and 255°C. This is the temperature range in which the metal alloy in the solder paste reaches a liquid state, allowing the solder paste to fully wet the pads and component pins.

[0064] In the production of the first DIP piece, wave soldering or selective soldering is used for soldering.

[0065] Depending on the component type and circuit board design, decide whether to use wave soldering or selective soldering. Wave soldering is suitable for soldering the entire PCB, while selective soldering is suitable for soldering in local areas.

[0066] If wave soldering is selected, prepare a wave soldering machine and adjust the wave height, temperature and speed to ensure the consistency and quality of the soldering process.

[0067] If you choose selective soldering, prepare the selective soldering equipment and program the machine's motion path according to the location of the soldering point.

[0068] According to the heat resistance of the components and the material characteristics of the PCB, set the soldering temperature and time. For wave soldering, make sure the temperature of the tin is appropriate, usually between 250℃ and 275℃.

[0069] Fix the PCB to be soldered on the conveyor belt of the soldering machine and prepare for soldering. For wave soldering, start the conveyor belt to make the PCB pass through the solder wave of the wave soldering machine; for selective soldering, start the soldering robot and perform local soldering according to the preset path. Use a real-time monitoring system during the soldering process, such as an infrared camera or a vision system, to monitor the formation of solder joints.

[0070] The visual inspection includes the inspection of component placement, welding quality and pin bending. Prepare an automated visual inspection system and ensure that its camera, lighting and software settings are correct so as to inspect the component placement, welding quality and pin status. Write a visual inspection program according to the PCB design documents and component specifications. The program needs to set the inspection standards, including the tolerance range of component position, the appearance standard of welding points and the bending angle of the pins. Use the AV I system to scan the PCB after mounting, automatically detect whether the components are correctly placed in the predetermined position according to the design documents, scan the PCB after welding, detect whether the welding points have good wetting, whether there are problems such as insufficient welding, excessive welding or welding bridge, detect whether the pins of the components are improperly bent or deformed, and record the inspection results in the MES system, including the PCBs that pass the inspection and the PCBs that need to be reworked. For the problem PCBs detected, they are automatically diverted to the rework area for manual or automatic rework.

[0071] In the test steps, the functional test includes voltage test, current test and signal integrity test on the circuit board. According to the design specifications and test requirements of the circuit board, prepare the corresponding test equipment and test plan. This may include multi-function testers, signal generators, oscilloscopes, etc. Write automated test programs, set test parameters and test sequences to ensure that all key voltage, current and signal integrity test points are covered. Perform voltage tests on key nodes on the circuit board to verify whether the power supply and signal voltages meet the design requirements. The test includes the measurement of DC voltage and AC peak-to-peak value. Perform current tests to verify whether the current on the circuit board is within the specified range, including static current and dynamic current tests. Perform signal integrity tests by sending test signals and analyzing their transmission quality on the circuit board. Check the attenuation, reflection and interference of the signal. Perform functional tests on the circuit board to verify whether all components and subsystems work normally according to the design requirements. This may include digital logic tests, analog signal response tests, etc. Perform performance tests to evaluate the performance of the circuit board under actual working conditions, such as frequency response, gain, distortion, etc. Record all test data and analyze them using statistical analysis methods to determine whether the circuit board meets the performance standards. For boards that fail the test, use diagnostic tools to perform fault diagnosis and determine the cause of the failure. Boards that fail the test are diverted to the rework area for repair.

[0072] After the testing step, a completion step and a warehousing step are also performed;

[0073] Finishing step, final testing and adjustment of the products that have completed all production and inspection processes, and then packaging;

[0074] In the warehousing step, the packaged products undergo a final quality review, check the quantity, inspect the packaging, determine the storage location, and update the inventory system.

[0075] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0076] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A circuit board production process, characterized in that: The following steps are involved: Process review, to evaluate the feasibility of the production process, including the review of materials, equipment, personnel and environmental conditions; Programming: Based on the PCB component layout and orientation information, write the operating program of the automatic placement machine to guide the placement machine to accurately place the electronic components at the predetermined position on the PCB; Check and prepare materials and components required for production according to the bill of materials and production plan; A bake step uses a moisture sensitivity bake test fixture to bake moisture-sensitive materials and components in a controlled environment to remove moisture; The first SMT patch is produced by printing solder paste on the pads of the PCB, and using an automatic placement machine to place electronic components on the solder paste to produce the first sample; SMT first piece inspection: visual inspection and X-ray inspection of SMT first piece samples to check PCB solder joints and component placement; SMT patch reflow, according to the first sample made by the SMT patch, the solder paste is printed on the pad of the PCB, the patch electronic components are placed on the solder paste using an automatic patch machine, and then soldered through a reflow oven; QC inspection, visual inspection and X-ray inspection, inspection of PCB solder joints and component placement; DIP first piece production, inserting DIP electronic components into pre-drilled holes on the PCB and soldering them to produce the first sample; DIP first-article inspection: visual inspection and X-ray inspection of DIP first-article samples to detect PCB solder joints and electronic component placement; DIP production, based on the samples made from the first DIP piece, subsequent production is carried out, DIP electronic components are inserted into the pre-drilled holes of the PCB and soldered; The test steps include performing functional tests and performance tests on the PCB after SMT to verify the electrical performance of the circuit board.

2. A circuit board production process according to claim 1, characterized in that: Before the SMT patch reflow soldering, it also includes steel mesh production; Steel mesh production, according to the pad design file of the printed circuit board, uses laser cutting technology to carve a steel mesh with a predetermined pattern on the stainless steel plate for solder paste printing.

3. A circuit board production process according to claim 2, characterized in that: In the steel mesh making step, the thickness of the steel mesh ranges from 0.06 mm to 0.20 mm.

4. A circuit board production process according to claim 1, characterized in that: In the program making step, the operation program of the automatic placement machine includes the settings of placement speed, placement pressure and rotation angle of the placement electronic components.

5. A circuit board production process according to claim 1, characterized in that: In the baking step, the temperature range of the moisture sensitivity baking test fixture is between 120° C. and 150° C.

6. A circuit board production process according to claim 1, characterized in that: In the SMT patch reflow soldering, the preheating temperature of the reflow soldering furnace ranges from 90°C to 120°C, the thermal activation temperature ranges from 150°C to 180°C, and the reflow temperature ranges from 230°C to 255°C.

7. A circuit board production process according to claim 1, characterized in that: In the production of the first DIP piece, wave soldering or selective soldering is used for soldering.

8. A circuit board production process according to claim 1, characterized in that: The visual inspection includes inspection of component placement, soldering quality, and lead bending.

9. A circuit board production process according to claim 1, characterized in that: In the test steps, the functional test includes performing voltage test, current test and signal integrity test on the circuit board.

10. A circuit board production process according to claim 1, characterized in that: After the testing step, a completion step and a warehousing step are also performed; Finishing step, final testing and adjustment of the products that have completed all production and inspection processes, and then packaging; In the warehousing step, the packaged products undergo a final quality review, check the quantity, inspect the packaging, determine the storage location, and update the inventory system.

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