PCB copper-clad plate pressing process

Abstract

The invention provides a PCB copper-clad plate pressing process, and relates to the technical field of electronic manufacturing, and the process comprises the following steps: S1, sampling a prepreg; s2, detecting the prepreg samples, recording TG values of all the samples, establishing a detection record table, and recording the TG value and detection conditions of each sample in detail; s3, the detected actual TG value is compared with the TG value of the prepreg factory identification, and the prepregs are classified and marked according to the comparison result; s4, batch processing is carried out on the prepregs with the TG values having deviation, so that the TG values of all the prepregs are restored to the factory state; and S5, after it is confirmed that the TG values of all the prepregs are restored to the factory state, setting specific parameters of the pressing machine according to pressing process parameters provided by a prepreg manufacturer. The PCB copper-clad plate pressing process aims at solving the key technical problems existing in the traditional process, and the stability of the pressing process and the reliability of the product are improved.

Description

Technical Field

[0001] The invention relates to the technical field of electronic manufacturing, and in particular to technical optimization of a PCB (printed circuit board) copper clad plate lamination process. Background Art

[0002] In the traditional PCB copper clad laminate lamination process, there are multiple technical challenges, which directly affect the final quality and performance of the product. First, the TG value (glass transition temperature) of the prepreg is a key parameter, which determines the reaction characteristics of the material during the lamination process and the heat resistance of the final product. However, due to the influence of storage conditions, time and environmental factors, the TG value of the prepreg may change, resulting in unstable lamination effect, which in turn affects the electrical properties and mechanical strength of the PCB copper clad laminate. Secondly, insufficient adhesion between the core board and the prepreg and copper plate is a common problem, which may lead to defects such as delamination and bubbles during the lamination process, seriously affecting the reliability and service life of the product. In addition, the control of temperature and pressure during the lamination process is extremely critical, and any improper operation may lead to a decline in product quality. At the same time, the cleanliness of the mold and the gap adjustment are also important factors affecting product quality. Residues on the mold surface or improper gaps may cause product indentation or contamination, which in turn affects the appearance and performance.

[0003] In view of the above technical problems, the existing PCB copper clad laminate lamination process often lacks effective solutions. Traditional processes often rely on empirical operations and lack accurate detection and classification of the TG value of the prepreg, resulting in instability during the lamination process and fluctuations in product performance. At the same time, there is a lack of systematic optimization measures for the adhesion between the core board and the prepreg, and the copper plate, as well as the control of the lamination parameters and mold status. Therefore, there is an urgent need for a new PCB copper clad laminate lamination process to solve the above problems and improve the stability and reliability of the product. Summary of the invention

[0004] The invention provides a PCB copper clad plate pressing process, which aims to solve key technical problems existing in traditional processes and improve the stability of the pressing process and the reliability of products.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions: A PCB copper clad plate pressing process comprises the following steps:

[0006] S1. Sampling the prepreg;

[0007] S2. Test the prepreg samples, record the TG values ​​of all samples, and establish a test record sheet to record the TG value and test conditions of each sample in detail;

[0008] S3, comparing the actual TG value detected with the TG value marked on the prepreg factory label, and classifying and marking the prepreg according to the comparison result;

[0009] S4. Batch process the prepregs with deviated TG values ​​to restore the TG values ​​of all prepregs to the factory state;

[0010] S5. After confirming that the TG values ​​of all prepregs have been restored to the factory state, set the specific parameters of the laminating machine according to the laminating process parameters provided by the prepreg manufacturer;

[0011] S6. Prepare core board and copper board whose TG value meets the manufacturer's requirements;

[0012] S7, pre-processing the selected core board;

[0013] S8, stacking the pretreated core board, the prepreg after the TG value is restored, and the copper board according to the stacking order required by the design;

[0014] S9, placing the stacked material group into a laminating machine, and laminating according to the set laminating parameters;

[0015] S10, after the pressing is completed, take out the pressed PCB copper clad board and conduct appearance inspection and quality inspection;

[0016] S11, the PCB copper clad boards that have passed the inspection are post-processed and stored in the warehouse.

[0017] In some embodiments, in step S1, the edge and the center of the prepreg are respectively selected for sampling.

[0018] In some embodiments, in step S4, storage conditions are adjusted or heat treatment is performed according to the degree of deviation. During the treatment, the change of the TG value of the semi-cured sheet is monitored in real time to ensure that it is restored to the factory state. After the treatment is completed, it is tested again.

[0019] In some embodiments, in step S5, before setting specific parameters of the laminating machine according to the laminating process parameters provided by the prepreg manufacturer, the laminating machine needs to be preheated and pre-pressed.

[0020] In some embodiments, in step S7, the pretreatment includes a preheating treatment, the preheating temperature is set in the range of 10-20°C lower than the lowest TG value of the prepreg, and the preheating time is controlled in the range of 10-30 minutes.

[0021] In some embodiments, after completing step S7, the mold of the laminating machine is cleaned and inspected.

[0022] In some embodiments, in step S11, the post-processing steps include cutting, grinding, and cleaning.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] First, by sampling and testing the prepreg at multiple locations and comparing the TG values ​​marked on the factory labels, the present invention can accurately classify and process the prepregs to ensure that the TG values ​​of all prepregs are restored to the factory state. This measure effectively solves the problem that the TG value of the prepreg changes due to storage conditions, time and other factors, and avoids the risk of reduced lamination effect and final product performance caused by this. By restoring the TG value of the prepreg, the stability of the lamination process and the reliability of the product are improved, so that the PCB copper clad laminate after lamination has more excellent electrical performance and heat resistance.

[0025] Secondly, the present invention pre-treats the core board, including preheating and other steps, to eliminate the internal stress of the core board and improve its adhesion to the prepreg. This innovative pre-treatment step significantly reduces the occurrence of defects such as delamination and bubbles, making the pressed PCB copper clad board smoother and firmer. Through pre-treatment, not only the quality of the product is improved, but also the risks of subsequent processing and use are reduced.

[0026] In addition, the present invention also focuses on the cleaning and inspection of the laminating machine mold, as well as the precise adjustment of the mold gap. By ensuring the cleanliness of the mold and the accuracy of the gap, the present invention further improves the stability and consistency of the product. The optimization of this detail makes the laminating process smoother, reduces product defects caused by mold problems, and improves production efficiency and product yield.

[0027] Finally, through strict appearance inspection and quality inspection, the present invention ensures that the pressed PCB copper clad laminate has no defects such as cracks, bubbles, delamination, etc., and meets the requirements of peel strength, electrical properties and heat resistance. This comprehensive quality inspection system provides a strong guarantee for the quality and performance of the product, making the PCB copper clad laminate of the present invention more competitive in the market. At the same time, the addition of post-processing procedures, such as cutting, grinding, cleaning, etc., further improves the appearance and performance of the product, and meets the customer's demand for high-quality PCB copper clad laminates.

[0028] In summary, the PCB copper clad laminate lamination process of the present invention achieves comprehensive optimization of the process and improves the stability and reliability of the product by solving key technical problems in the traditional process. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flowchart of steps S1-S4 of the present invention (prepreg TG value adjustment process);

[0030] Figure 2 It is a flowchart of steps S5-S11 of the present invention (pressing process). DETAILED DESCRIPTION

[0031] The embodiments of the present invention are described in detail below.

[0032] like Figure 1-2 As shown, this embodiment provides a PCB copper clad plate pressing process, including the following steps:

[0033] S1. Sampling the prepreg. For the prepreg whose TG value is changed due to the environment, multiple sampling tests are required to detect its actual TG value, and the sampled prepreg is marked for subsequent testing and comparison;

[0034] S2. Test the prepreg samples and record the TG values ​​of all samples. The test can be performed using a thermomechanical analyzer or a differential scanning calorimeter to accurately measure the TG value of the prepreg, and a test record sheet is established to record the TG value and test conditions of each sample in detail;

[0035] S3, comparing the actual TG value detected with the TG value marked on the prepreg factory label, classifying the prepregs according to the comparison results, marking the prepregs with TG value deviations, and using the TG value deviation range set before the comparison, such as ±5°C, as a classification standard, marking the prepregs beyond the deviation range for subsequent processing;

[0036] S4. Batch process the prepregs with deviated TG values ​​to restore the TG values ​​of all prepregs to the factory state, and ensure that the restored TG values ​​are stable and reliable;

[0037] S5. After confirming that the TG values ​​of all prepregs have been restored to the factory state, set the specific parameters of the laminating machine according to the laminating process parameters provided by the prepreg manufacturer, such as laminating temperature, pressure, time, etc.;

[0038] In the above steps, by sampling and testing the prepregs at multiple locations and comparing the TG values ​​marked on the factory labels, accurate classification and processing of the prepregs are achieved, ensuring that the TG values ​​of all prepregs are restored to the factory state, thereby improving the stability of the lamination process and the reliability of the product;

[0039] S6. Take the core board and copper board whose TG value meets the manufacturer's requirements, and ensure that the surface of the core board and copper board are flat and flawless, without oil stains and impurities attached;

[0040] S7, pre-processing the selected core board;

[0041] S8, stack the pretreated core board, the prepreg after the TG value is restored, and the copper board in the stacking order required by the design to form a structure of copper board-prepreg-core board-prepreg-copper board or copper board-prepreg-core board, and place a release film or isolation paper between each layer to prevent premature adhesion, check the stacked material group, and ensure that the stacking order and spacing meet the design requirements;

[0042] S9, placing the stacked material group into the laminating machine, and laminating according to the set laminating parameters. During the laminating process, the temperature and pressure changes need to be monitored in real time to ensure the stability of the laminating process;

[0043] S10. After the lamination is completed, when the temperature drops to a safe range, take out the laminated PCB copper clad laminate, conduct appearance inspection and quality inspection to confirm that there are no defects such as cracks, bubbles, delamination, etc., and test its peel strength, electrical properties and heat resistance. Through strict appearance inspection and quality inspection, it is ensured that the laminated PCB copper clad laminate has no defects such as cracks, bubbles, delamination, etc., and meets the requirements of peel strength, electrical properties and heat resistance;

[0044] S11. The PCB copper clad laminates that have passed the inspection are post-processed and stored in the warehouse. Through the systematic process flow and post-processing procedures, efficient and stable PCB copper clad laminate production is achieved, and production efficiency and product yield are improved.

[0045] Through the above technical solutions, the PCB copper clad laminate lamination process has been fully optimized. First, by sampling and testing the prepreg at multiple locations and comparing the TG value marked on the factory label, the TG value of all prepregs is ensured to be restored to the factory state, thereby improving the stability of the lamination process and the reliability of the product. This measure effectively solves the problem of changes in the TG value of the prepreg due to storage conditions, time and other factors, and avoids the risk of reduced lamination effect and final product performance caused by this.

[0046] Secondly, this solution pre-processes the core board, including preheating and other steps, eliminating the internal stress of the core board, improving its adhesion with the prepreg, and reducing the occurrence of defects such as delamination and bubbles. This innovative pre-processing step significantly improves the quality and performance of the product, making the pressed PCB copper clad board smoother and firmer.

[0047] In addition, this solution also focuses on the cleaning and inspection of the laminating machine mold, as well as the precise adjustment of the mold gap, ensuring uniform pressure distribution during the laminating process, further improving the stability and consistency of the product. This detail optimization makes the laminating process smoother and reduces product defects caused by mold problems.

[0048] Finally, through strict appearance inspection and quality inspection, this solution ensures that the pressed PCB copper clad laminate has no defects such as cracks, bubbles, delamination, etc., and meets the requirements of peel strength, electrical properties and heat resistance. This comprehensive quality inspection system provides a strong guarantee for the quality and performance of the product, making the PCB copper clad laminate of the present invention more competitive in the market.

[0049] In certain embodiments, in step S1, the edge and center of the prepreg are selected for sampling respectively. The edge and center area of ​​the prepreg may be affected by different degrees of environmental influences due to their positional differences, resulting in differences in the change of TG values. By sampling at the edge and center simultaneously, the actual TG value distribution of the prepreg can be obtained more comprehensively, avoiding the one-sidedness that may be caused by sampling only from a single position, thereby improving the accuracy and reliability of detection. The edge area may be more susceptible to the influence of conditions such as temperature and humidity due to being closer to the external environment, resulting in changes in the TG value. The center area is relatively stable, but it may also cause TG value deviations due to internal stress or material inhomogeneity. By detecting these two areas simultaneously, potential problem areas can be discovered and located in time, providing a more targeted basis for subsequent classification processing.

[0050] And according to the difference in TG values ​​sampled at the edge and the center, a more refined treatment plan can be formulated. For example, for prepregs with large deviations in TG values ​​at the edge, more stringent recovery treatment measures can be taken, such as increasing the heat treatment temperature or extending the treatment time; while for prepregs with relatively stable TG values ​​in the center, a more gentle treatment method can be used to save cost and time.

[0051] In some embodiments, in step S4, storage conditions are adjusted or heat treatment is performed according to the degree of deviation. During the process, the TG value change of the prepreg is monitored in real time to ensure that it is restored to the factory state. After the process is completed, it is tested again. Through precise processing, real-time monitoring and feedback, and double detection guarantees, step S4 ensures that the TG value of the prepreg can be accurately and stably restored to the factory state, thereby improving the stability of the lamination process and the reliability of the product.

[0052] In some embodiments, in step S5, before setting the specific parameters of the laminating machine according to the laminating process parameters provided by the prepreg manufacturer, the laminating machine needs to be preheated and pre-pressed. Through the preheating and pre-pressing tests, possible problems of the laminating machine can be found in advance, such as damage to the heating element, leakage of the pressure system, etc., so as to timely repair or replace it, and avoid equipment failure during the formal laminating process, resulting in production interruption or product scrapping. And during the preheating and pre-pressing tests, it can be verified whether the temperature control and pressure control system of the laminating machine are accurate and reliable. Through actual testing, the parameter settings of the laminating machine, such as the calibration of the temperature sensor, the sensitivity of the pressure sensor, etc., can be adjusted and confirmed to ensure that these parameters can be accurately executed during the formal laminating process. In addition, the preheating and pre-pressing tests can also help optimize the laminating effect. Through testing, the working performance of the laminating machine under different parameters, such as temperature distribution uniformity, pressure transmission efficiency, etc., can be understood, so as to adjust the laminating parameters according to the test results, so that the laminating process is more stable and reliable, and the quality and performance of the product are improved.

[0053] In some embodiments, in step S7, the pretreatment includes a preheating treatment, and the preheating temperature is set within a range of 10-20°C lower than the lowest TG value of the semi-cured sheet, and the preheating time is controlled within 10-30 minutes to eliminate the internal stress of the core board and improve its adhesion to the semi-cured sheet, while ensuring that the core board does not undergo chemical changes prematurely due to excessively high temperatures. By preheating the core board, the internal stress is eliminated, the adhesion between the core board and the semi-cured sheet is improved, and the occurrence of defects such as delamination and bubbles is reduced. During the preheating treatment, equipment such as a constant temperature box or a heating plate can be used to ensure accurate temperature control.

[0054] In some embodiments, after completing step S7, the mold of the laminating machine is cleaned and inspected. This step includes using a cleaning agent and a high-pressure airflow to remove all residues on the surface of the mold, such as glue stains, dust particles and oil stains. At the same time, a high-precision surface detection tool, such as an optical plane or a laser scanner, is used to check whether the mold surface is flat and undamaged to ensure that there are no protrusions, depressions or scratches, so as to prevent these defects from causing indentations or contaminating the PCB board during the laminating process, affecting the appearance and performance of the product. This step is a key link in ensuring the stability of the laminating process and the consistency of the product, and is of great significance for improving the production quality and efficiency of PCB copper clad laminates.

[0055] In some embodiments, in step S11, the post-processing steps include cutting, grinding, and cleaning.

[0056] The cutting process uses a high-precision CNC cutting machine or laser cutting equipment to accurately cut the laminated PCB copper-clad board according to the size and shape requirements of the product design. This step ensures the dimensional accuracy and edge flatness of the product, avoiding subsequent assembly or electrical connection problems caused by inaccurate cutting. During the cutting process, the dust collection system equipped with the equipment can effectively collect the debris generated by cutting to keep the working environment clean.

[0057] The grinding process uses fine-grained sandpaper or grinding wheels to grind the edges of the cut PCB copper-clad boards to remove burrs and sharp edges generated during the cutting process, improving the safety and aesthetics of the product. Grinding can also promote better bonding between the edges and subsequent coatings or welding materials, and enhance the overall structural strength of the product. By controlling the grinding intensity and time, you can ensure that the edges are smooth without damaging the internal circuit structure.

[0058] The cleaning process uses an ultrasonic cleaning machine or a high-pressure spray cleaning system, with a special cleaning agent, to thoroughly clean the polished PCB copper-clad board to remove debris, oil, fingerprints and other pollutants remaining on the surface. The cleaning process not only ensures the surface cleanliness of the product, but also provides good conditions for subsequent coating, welding or assembly processes. Ultrasonic cleaning can effectively penetrate tiny gaps and remove dirt that is difficult to observe with the naked eye, ensuring thorough cleaning of the inside and outside of the product.

[0059] The technical solution of the present invention realizes the comprehensive optimization of the PCB copper clad laminate lamination process through refined step design, strict quality control and innovative pretreatment measures. For example, the following is a lamination process of a certain PCB copper clad laminate based on the above technical solution:

[0060] a. Prepreg Sampling and Testing

[0061] Sampling location: Randomly select 3 prepregs to be used, and take one sample from the edge, center and random position of each board, for a total of 9 samples;

[0062] Sampling tools: Use professional cutting tools to ensure that the sample size is consistent, approximately 5cmx5cm;

[0063] Labeling method: Use waterproof labels to number each sample and record the sampling location;

[0064] b. TG value test of prepreg samples

[0065] Testing instrument: A thermomechanical analyzer (TMA) was used, and the test conditions were set to a heating rate of 5°C / min and a test range of 30°C to 300°C;

[0066] Recording method: Establish an electronic test record sheet to record in detail the TG value, test date, time and instrument model of each sample;

[0067] c. TG value comparison and classification

[0068] Comparison standard: Based on the TG value of the prepreg factory label, the deviation range is set to ±5℃;

[0069] Classification marking: Prepregs that exceed the tolerance range are marked with red labels, and qualified ones are marked with green labels;

[0070] d. Treatment of TG value recovery of prepreg

[0071] Treatment plan: For prepregs with low TG values, use heat treatment at 80°C for 24 hours; for those with high TG values, adjust the storage environment to 20°C±2°C, humidity 50%±5%, and store for 72 hours;

[0072] Monitoring method: Use TMA to detect TG value every 6 hours until it returns to the factory state;

[0073] e. Laminating machine parameter setting

[0074] Lamination temperature: set to 180℃±5℃ according to the recommendation of the prepreg manufacturer;

[0075] Pressure: set to 3MPa to ensure even distribution;

[0076] Time: The total pressing time is 90 minutes, including preheating, pressing and cooling stages;

[0077] Preheating and preloading: Perform a 15-minute preheating and a 5-minute preloading test to confirm that the equipment is correct;

[0078] f. Preparation of core board and copper board

[0079] Material selection: Select core board and copper board with TG value meeting the requirements, and surface roughness Ra≤0.02μm;

[0080] Cleaning: Use anhydrous ethanol to wipe the surface to remove oil and impurities;

[0081] g. Core board pretreatment

[0082] Preheating temperature: set to 160°C;

[0083] Warm-up time: 20 minutes;

[0084] Equipment: Use a constant temperature box for preheating;

[0085] h. Mold cleaning and adjustment

[0086] Cleaning tools: Use an ultrasonic cleaner to clean the mold to ensure there is no residue;

[0087] Gap adjustment: According to the total thickness of the core board and the prepreg, adjust the mold gap to 1.6mm to ensure uniform pressure;

[0088] i. Material stacking

[0089] Lamination sequence: copper plate-prepreg-core plate-prepreg-copper plate;

[0090] Isolation material: Place a 0.05mm thick release film between each layer;

[0091] Inspection: Use a vernier caliper to check the stacking thickness and spacing to ensure that they meet the design requirements;

[0092] j. Lamination process

[0093] Monitoring: Use temperature sensors and pressure sensors for real-time monitoring to ensure that the temperature fluctuation does not exceed ±2°C and the pressure is stable;

[0094] Record: record key data during the pressing process, such as maximum temperature, maximum pressure and duration;

[0095] k. Appearance inspection and quality testing

[0096] Appearance inspection: Use a magnifying glass to check the surface of the PCB copper clad board to confirm that there are no cracks, bubbles, or delamination;

[0097] Quality inspection: The peel strength test uses a tensile testing machine, the electrical performance test uses an impedance tester, and the heat resistance test is carried out at a constant temperature of 200℃ for 2 hours to observe the changes;

[0098] 1. Post-processing and storage

[0099] Cutting: Use precision cutting machine to cut according to design requirements;

[0100] Sanding: Use fine sandpaper to sand the edges and remove burrs;

[0101] Cleaning: Use anhydrous ethanol to clean the surface again;

[0102] Packaging and labeling: Use anti-static bags for packaging and affix product labels including production date, batch number and qualified mark;

[0103] Storage: Store in a warehouse at a temperature of 20℃±5℃ and a humidity of 50%±10%.

[0104] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A PCB copper clad laminate lamination process, characterized in that: The following steps are involved: S1. Sampling the prepreg; S2. Test the prepreg samples, record the TG values ​​of all samples, and establish a test record sheet to record the TG value and test conditions of each sample in detail; S3, comparing the actual TG value detected with the TG value marked on the prepreg factory label, and classifying and marking the prepreg according to the comparison result; S4. Batch process the prepregs with deviated TG values ​​to restore the TG values ​​of all prepregs to the factory state; S5. After confirming that the TG values ​​of all prepregs have been restored to the factory state, set the specific parameters of the laminating machine according to the laminating process parameters provided by the prepreg manufacturer; S6. Prepare core board and copper board whose TG value meets the manufacturer's requirements; S7, pre-processing the selected core board; S8, stacking the pretreated core board, the prepreg after the TG value is restored, and the copper board according to the stacking order required by the design; S9, placing the stacked material group into a laminating machine, and laminating according to the set laminating parameters; S10, after the pressing is completed, take out the pressed PCB copper clad board and conduct appearance inspection and quality inspection; S11, the PCB copper clad boards that have passed the inspection are post-processed and stored in the warehouse.

2. A PCB copper clad laminate lamination process according to claim 1, characterized in that: In step S1, the edge and the center of the prepreg are respectively selected for sampling.

3. A PCB copper clad laminate lamination process according to claim 1, characterized in that: In step S4, storage conditions are adjusted or heat treatment is performed according to the degree of deviation. During the treatment, the TG value change of the prepreg is monitored in real time to ensure that it is restored to the factory state. After the treatment is completed, the test is performed again.

4. A PCB copper clad laminate lamination process according to claim 1, characterized in that: In step S5, before setting the specific parameters of the laminating machine according to the laminating process parameters provided by the prepreg manufacturer, the laminating machine needs to be preheated and pre-pressed.

5. A PCB copper clad laminate lamination process according to claim 1, characterized in that: In step S7, the pretreatment includes a preheating treatment, the preheating temperature is set in the range of 10-20°C lower than the lowest TG value of the prepreg, and the preheating time is controlled in the range of 10-30 minutes.

6. A PCB copper clad laminate lamination process according to claim 1, characterized in that: After completing step S7, the mold of the laminating machine is cleaned and inspected.

7. A PCB copper clad laminate lamination process according to claim 1, characterized in that: In step S11, the post-processing steps include cutting, grinding, and cleaning.

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