Mobile air conditioner panel manufacturing process based on multi-layer PCB

Abstract

The invention relates to the technical field of mobile air conditioner panel manufacturing processes, in particular to a mobile air conditioner panel manufacturing process based on a multi-layer PCB, and the process comprises the steps: forming a PCB attaching substrate; attaching a component patch to the patch position to form a pre-fixed PCB; acquiring a plurality of frames of three-dimensional images of the solder on the bonding pad, determining a compact area and a dispersed area, and positioning a tending tearing surface based on the duration of the compact area and the dispersed area; comparing the texture features of the prediction compact area and the prediction dispersion area on the two sides of the surface tending to be torn with the texture features generated by pressure; if the texture features are consistent, determining the pressure of the suction nozzle of the chip mounter; determining the heating rate of an attaching area according to the distribution height of the heated solder, and carrying out actual heating, melting and cooling on the pre-fixed PCB to form a multi-layer PCB assembly board; the multi-layer PCB assembly board and the mobile air conditioner substrate are attached to form a mobile air conditioner panel; according to the invention, the manufacturing accuracy of the multi-layer PCB is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of mobile air-conditioning panel manufacturing technology, and in particular to a mobile air-conditioning panel manufacturing technology based on a multi-layer PCB. Background Art

[0002] With the rapid development of smart home and Internet of Things technologies, mobile air conditioners have become indispensable equipment in modern home and office environments. The distribution of solder in the existing PCB manufacturing process of mobile air conditioner panels affects the attachment accuracy of component patches.

[0003] In the prior art, Chinese patent publication number CN216897752U discloses a square display panel for an air conditioner wall-mounted unit, comprising a substrate, a plastic housing, and electronic components. The substrate is a single-layer PCB board, and a circuit pattern is formed only on the upper side of the substrate. All electronic components are soldered to the upper side of the substrate in a surface-mounted manner and are conductively connected to the circuit pattern to construct a working circuit for the air conditioner wall-mounted unit display. The electronic components include surface-mounted lamp beads, surface-mounted receiving heads, surface-mounted capacitors, and surface-mounted terminal blocks. The surface-mounted lamp beads are arranged in a preset dot matrix so that the surface-mounted lamp beads of different circuits emit light in combination to construct a display circuit state. The plastic housing is fixed to the upper side of the substrate and covers the surface-mounted lamp beads, and a plurality of reflective cavities are hollowed out on the plastic housing, and the center position of the bottom cavity opening of each reflective cavity corresponds to a surface-mounted lamp bead. The utility model does not require a series of complex processes such as additional shaping, plug-in operation and wave soldering of components, simplifies the production process, is highly efficient, and greatly reduces material and labor costs. It can be seen that the square display panel of the air conditioner wall-mounted unit has the problem that the solder on the PCB board pad forms dense areas and dispersed areas with different solder density conditions due to temperature gradient and heat dissipation differences during the melting and cooling process, thereby resulting in the generation of a tearing surface and reducing electrical connectivity. Summary of the Invention

[0004] To this end, the present invention provides a mobile air-conditioning panel manufacturing process based on a multi-layer PCB, which is used to overcome the problem in the prior art that during the melting and cooling process of the solder on the PCB board pad, the solder forms dense areas and dispersed areas with different solder density conditions due to temperature gradients and heat dissipation differences, thereby resulting in the generation of tearing surfaces and reduced electrical connectivity.

[0005] To achieve the above objectives, the present invention provides a manufacturing process for a mobile air-conditioning panel based on a multi-layer PCB, comprising: Spreading solder onto a multi-layer PCB to form a PCB attachment substrate; Attaching component patches to corresponding patch positions on the PCB attachment substrate by the nozzle of the patch machine to form a pre-fixed PCB board; Performing a melting and cooling test on the solder on the pre-fixed PCB board, and acquiring several frames of three-dimensional images of the solder on the pre-fixed PCB board; determining a dense area and a dispersed area according to the plurality of frames of three-dimensional images; Positioning a tearing-prone surface of the solder based on a duration of the dense region and a duration of the dispersed region; The texture characteristics of the dense and dispersed areas on both sides of the tear surface are compared with the texture characteristics generated during the component patch attachment process. If the texture features are consistent, it is determined that the attachment pressure generated by the nozzle is in an abnormal state, and the nozzle pressure is re-determined according to the abnormal state; Determine the heating rates of the outer portion and the inner portion of the attachment area according to the distribution height of the heated solder having consistent texture characteristics; The pre-fixed PCB is actually heated and cooled according to the heating rate to fix the components to the corresponding patch positions on the pre-fixed PCB to form a multi-layer PCB assembly; Laminating the multi-layer PCB assembly board to a mobile air conditioner substrate to form a mobile air conditioner panel; The heating parameters on both sides of the tearing surface are related to the duration.

[0006] Furthermore, determining the dense area and the dispersed area according to the plurality of three-dimensional image frames includes: Extracting solder density at a plurality of density sampling points arranged at equal intervals in the plurality of frames of three-dimensional images; Determine the largest closed three-dimensional area formed by connecting the first corresponding density sampling points that meet the solder density condition as the dense area; Determine the entire solder three-dimensional space occupied by the second corresponding density sampling points that do not meet the solder density condition as the scattered area; Furthermore, the solder density condition is that the solder density at the density sampling point is greater than a preset density.

[0007] Furthermore, the tearing surface is positioned according to the duration of the dense area and the dispersed area at the melting temperature, wherein: The tearing-tendency surface is formed when the solder cools due to temperature gradient and heat dissipation difference, and the interface between the largest closed three-dimensional areas in the dense area and the dispersed area is the tearing-tendency surface.

[0008] Furthermore, the melting temperature is the temperature at which a melting cooling test is performed on the solder on the pre-fixed PCB board.

[0009] Furthermore, the texture features of the predicted dense area and the predicted dispersed area on both sides of the tearing surface are compared with the texture features generated by the downward vertical torque transmitted by the nozzle of the placement machine, including extracting the first texture features of the predicted dense area and the predicted dispersed area through the three-dimensional image of the pre-fixed PCB board; obtaining the second texture features generated by the downward vertical torque transmitted by the simulated placement machine nozzle, wherein, If the similarity between the first texture feature and the second texture feature is greater than or equal to 90%, it is determined that the first texture feature and the second texture feature are consistent.

[0010] Furthermore, the specific standard of pressure abnormality is determined based on the similarity of texture features. The pressure abnormality is that the downward vertical torque transmitted by the placement machine nozzle is greater than the preset torque, and the state of the placement machine nozzle is determined to be abnormal at this time. The first pressure value of the placement machine nozzle is extracted based on the second texture feature, and the first pressure value is adjusted to the preset pressure value.

[0011] Furthermore, when the vertical distribution height of the solder calculated by the Z-axis coordinate of the three-dimensional image is greater than the preset distribution height, the heating rate of the outer portion of the attachment area is increased to the first heating rate, and the heating rate of the inner portion of the attachment area is reduced to the second heating rate to guide the solder to flow outward through the temperature gradient, wherein, The attachment area is the three-dimensional space area of ​​the solder of a single solder joint corresponding to the component patch, and is identified by the contact boundary between the solder and the PCB substrate in the three-dimensional image; Furthermore, the first heating rate is greater than the second heating rate.

[0012] Furthermore, based on the inconsistency between the first texture feature and the second texture feature, that is, the similarity between the first texture feature and the second texture feature is less than 90%, the heating temperature of the dense area is increased and the heating temperature of the dispersed area is decreased according to the tearing surface.

[0013] Compared with the prior art, the beneficial effect of the present invention lies in that the present invention determines the dense area and dispersed area of ​​the solder on the pad by sequentially performing melting and cooling tests on the solder on the pre-fixed PCB board and obtaining several frames of three-dimensional images of the solder on the pad, and locates the tearing surface based on the duration of the dense area and the dispersed area, thereby mastering the distribution state of the solder during the heating and cooling processes and predicting in advance the risk of splitting of the solder due to thermal stress or uneven pressure distribution; by comparing the texture features of the predicted dense area and the predicted dispersed area on both sides of the tearing surface with the texture features generated by pressure pressing, it is determined whether the tearing surface is generated by pressure pressing, thereby further adjusting the heating temperature, heating rate, nozzle pressure and other process parameters in a targeted manner to avoid uneven solder distribution or tearing defects and improve welding quality and reliability.

[0014] Furthermore, the present invention obtains a three-dimensional image of the pre-fixed PCB board to determine the dense area and dispersed area of ​​the solder at the melting temperature, locates the tearing surface, and thus determines the area where the solder may tear during the heating process.

[0015] Furthermore, the present invention determines whether the tearing surface tending to be transformed into an actual tearing surface by detecting the duration of the dense area and the dispersed area. If the predicted dense area and the dispersed area merge during the heating process, the actual tearing surface will not be generated.

[0016] Furthermore, the present invention predicts that the dense area and the dispersed area are not fused during the heating process. The texture features of the predicted dense areas and predicted dispersed areas on both sides of the tearing surface are analyzed and compared with the texture features generated by the downward vertical torque transmitted by the placement machine nozzle to determine whether the tearing surface is generated by the downward vertical torque transmitted by the placement machine nozzle. If the two are consistent, the pressure value of the placement machine nozzle is adjusted accordingly to improve the electrical connectivity of the PCB board.

[0017] Furthermore, the present invention specifically adjusts the heating temperature on both sides of the tearing surface based on the inconsistency between the first texture feature and the second texture feature, so that the dense area and the dispersed area around the tearing surface are effectively merged.

[0018] Furthermore, the present invention adjusts the heating rate when the vertical distribution height of the solder calculated through the Z-axis coordinate of the three-dimensional image is greater than the preset distribution height, so that the temperature gradient guides the solder to flow outward to compensate for the accumulation of solder on the outside caused by the excessive vertical torque of the placement machine nozzle. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is an overall flow chart of the manufacturing process of a mobile air-conditioning panel based on a multi-layer PCB according to an embodiment of the present invention; Figure 2-1 This is a schematic diagram of the connection between component patches, solder, pads, and the tearing surface of the solder in the manufacturing process of a mobile air-conditioning panel based on a multi-layer PCB according to an embodiment of the present invention; Figure 2-2 This is a schematic diagram of the connection between component patches and pads, as well as the outer and inner portions of the solder attachment area in the manufacturing process of a mobile air-conditioning panel based on a multi-layer PCB according to an embodiment of the present invention; Figure 3 This is a flow chart for determining dense and dispersed areas in a manufacturing process for a mobile air-conditioning panel based on a multi-layer PCB according to an embodiment of the present invention; Explanation of the accompanying figures: 1-component patch, 2-solder, 3-pad, 4-tear-tending surface, 5-outer part of the attachment area, 6-inner part of the attachment area. DETAILED DESCRIPTION

[0020] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0021] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0022] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside", and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0023] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0024] See also Figure 1 、 Figure 2-1 、 Figure 2-2 as well as Figure 3 As shown, they are respectively an overall flow chart of the manufacturing process of a mobile air-conditioning panel based on a multi-layer PCB according to an embodiment of the present invention, a schematic diagram of the connection between the component patch and the solder and the pad, and the tearing surface of the solder, a schematic diagram of the connection between the component patch and the pad, and the outer part of the attachment area and the inner part of the attachment area of ​​the solder, and a flow chart for determining the dense area and the dispersed area; the manufacturing process of a mobile air-conditioning panel based on a multi-layer PCB according to an embodiment of the present invention includes: Spreading solder 2 onto the multi-layer PCB to form a PCB attachment substrate; The component patch 1 is attached to the corresponding patch position on the PCB attachment substrate by the nozzle of the patch machine to form a pre-fixed PCB board; Performing a melting and cooling test on the solder 2 on the pre-fixed PCB board, and acquiring several frames of three-dimensional images of the solder 2 on the pre-fixed PCB board; determining a dense area and a dispersed area according to the plurality of frames of three-dimensional images; Positioning the tearing-prone surface 4 of the solder 2 based on the duration of the dense area and the duration of the dispersed area; Comparing the texture features of the dense and dispersed areas on both sides of the tear surface 4 with the texture features generated during the attachment process of the component patch 1; If the texture features are consistent, it is determined that the attachment pressure generated by the nozzle is in an abnormal state, and the nozzle pressure is re-determined according to the abnormal state; Determine the heating rates of the outer portion and the inner portion of the attachment area according to the distribution height of the heated solder 2 having consistent texture characteristics; The pre-fixed PCB is actually heated and cooled according to the heating rate to fix the components to the corresponding patch positions on the pre-fixed PCB to form a multi-layer PCB assembly; Laminating the multi-layer PCB assembly board to a mobile air conditioner substrate to form a mobile air conditioner panel; The heating parameters on both sides of the tearing surface 4 are related to the duration.

[0025] Specifically, a multi-layer PCB is a complex circuit board made up of multiple conductive layers and insulating layers stacked alternately, including a conductive layer, an insulating layer, vias, a solder mask layer, a silk screen layer, a power layer and a ground layer, a signal layer, a core layer and a prepreg layer, as well as pads 3 located on the surface layer of the PCB.

[0026] Specifically, the duration is the time period from when the solder 2 begins to melt at the melting temperature to when it begins to cool.

[0027] In the present invention, the component patch 1 uses a 0603 package resistor, the thickness of the solder 2 is 0.2 mm, and the laying temperature of the solder 2 is 180°C.

[0028] Specifically, a three-dimensional scanner is used to obtain a three-dimensional image of the pre-fixed PCB board.

[0029] In practice, the present invention performs melting and cooling tests on the solder 2 on the pre-fixed PCB board in sequence, and obtains several frames of three-dimensional images of the solder 2 on the pad 3 to determine the dense area and dispersed area of ​​the solder 2 on the pad 3, and locates the tearing surface 4 based on the duration of the dense area and the dispersed area, so as to grasp the distribution state of the solder 2 during the heating process and the cooling process and predict in advance the risk of splitting of the solder 2 due to thermal stress or uneven pressure distribution; by comparing the texture features of the predicted dense area and the predicted dispersed area on both sides of the tearing surface 4 with the texture features generated by pressure pressing, it is determined whether the tearing surface 4 is generated by pressure pressing, so as to further adjust the process parameters such as heating temperature, heating rate, nozzle pressure, etc. in a targeted manner to avoid uneven distribution or tearing defects of the solder 2 and improve the welding quality and reliability.

[0030] See also Figure 3 As shown, the determining of the dense area and the dispersed area based on the plurality of frames of three-dimensional images includes: Extracting solder density at a plurality of density sampling points arranged at equal intervals in the plurality of frames of three-dimensional images; Determine the largest closed three-dimensional area formed by connecting the first corresponding density sampling points that meet the solder density condition as the dense area; The entire three-dimensional space of the solder 2 occupied by the second corresponding density sampling points that do not meet the solder density condition is determined as the scattered area.

[0031] Specifically, the plurality of frames of three-dimensional images are a plurality of frames of three-dimensional ultrasound images generated by ultrasound detection.

[0032] Specifically, the solder density condition is that the solder density at the density sampling point is greater than a preset density.

[0033] A specific embodiment is that under the condition of standard pad 3, the average solder density is 8.0g / , the preset density is set to 90% of the average solder density, that is, the preset density is 7.2g / .

[0034] In practice, the present invention obtains a three-dimensional image of the pre-fixed PCB board, determines the dense area and the dispersed area of ​​the solder 2 at the melting temperature, locates the tearing surface 4, and thus determines the area where the solder 2 may tear during the heating process.

[0035] Specifically, the tearing surface 4 is positioned according to the duration of the dense area and the dispersed area at the melting temperature, wherein: The tearing-tendency surface 4 is formed when the solder 2 cools due to the temperature gradient and the heat dissipation difference. The interface between the largest closed three-dimensional areas in the dense area and the dispersed area is the tearing-tendency surface 4.

[0036] In a specific embodiment, under the condition of a standard solder pad 3 , if the dense area and the dispersed area are completely fused within 10 to 20 seconds, it indicates that the solder 2 is evenly distributed and no actual tearing surface is generated.

[0037] In practice, the present invention determines whether the tearing surface 4 will be transformed into an actual tearing surface by detecting the duration of the dense area and the dispersed area. If the predicted dense area and the dispersed area merge during the heating process, the actual tearing surface will not be generated.

[0038] Specifically, the melting temperature is the temperature at which the solder 2 on the pre-fixed PCB board is subjected to a melting cooling test.

[0039] Optionally, the melting temperature range is [210°C, 230°C].

[0040] Preferably, in this embodiment, the component patch 1 uses a 0603 package resistor, and the melting temperature is set to 220°C to ensure that the solder 2 is fully melted and forms a good solder joint, while avoiding damage to the component or PCB substrate caused by excessive temperature. The PCB substrate is easily damaged at an ambient temperature above 260°C.

[0041] Specifically, the heating parameters include the location of dense and dispersed regions and the heating temperature. After the heating area is located, the heating temperature is increased in a gradient to no more than 255°C according to the time the dispersed area and the dense area last. The calculation formula of the heating temperature and the duration is:

[0042] Where T is the heating temperature, is the melting temperature, k is the temperature gradient coefficient, and t is the duration of the dispersed region / dense region, where the duration of the dispersed region is equal to that of the dense region.

[0043] In a specific embodiment, the solder density at the density sampling point is extracted by using several frames of three-dimensional ultrasonic images generated by ultrasonic detection, and the dispersed area and the dense area are determined as the heating area. Under the condition of the standard solder pad 3, if the dispersed area and the dense area are completely fused within 5 seconds, the heating temperature and duration are calculated according to the formula: T = 220 + 2 × 5 = 230 ° C, that is, the heating temperature is 230 ° C; If the duration of the dispersed area and the dense area exceeds 20 seconds, the calculation formula of heating temperature and duration is: T=220+0.5×t. For example, if the area is not fused for more than 25 seconds, the heating temperature is T=220+0.5×25=232.5℃, where When the duration is short, it means that the fusion speed of the dispersed area and the dense area is fast and the difficulty is low. In this case, it is necessary to quickly increase the temperature by using a larger k and use the temperature gradient in a short time to accelerate the fusion; If the duration is long, it means that the fusion is difficult. If k is too large, the temperature will continue to rise rapidly, which may cause problems such as overheating of the pad and solder oxidation. Therefore, a smaller k is needed to slowly increase the temperature while ensuring fusion and controlling the upper temperature limit. For example, when t≤5s, k=2; When 5s<t ≤10s, k=1.5; When 10s<t≤20s, k=1; When t>20s, k=0.5.

[0044] Specifically, the texture features of the predicted dense area and the predicted dispersed area on both sides of the tearing surface 4 are compared with the texture features generated by the downward vertical torque transmitted by the nozzle of the placement machine, including extracting the first texture features of the predicted dense area and the predicted dispersed area through the three-dimensional image of the pre-fixed PCB board; obtaining the second texture features generated by the downward vertical torque transmitted by the simulated placement machine nozzle, wherein, If the similarity between the first texture feature and the second texture feature is greater than or equal to 90%, it is determined that the first texture feature and the second texture feature are consistent.

[0045] Specifically, the first texture feature and the second texture feature are acquired through a three-dimensional scanner, and the texture directionality and microscopic morphology features are extracted using a gray-level co-occurrence matrix algorithm. The extracted texture features are quantized into numerical values ​​or vectors for comparison with the second texture feature. If the similarity between the first texture feature and the second texture feature exceeds 90%, it is determined that the first texture feature and the second texture feature are consistent.

[0046] Specifically, the characteristic parameters of the first texture feature extracted include contrast reflecting the clarity of the texture; energy reflecting the uniformity of the texture; entropy reflecting the complexity of the texture; and correlation reflecting the directionality of the texture, wherein uniformity describes the regularity or consistency of the grayscale distribution in the texture. Complexity describes the degree of disorder or irregularity of grayscale variations in a texture; Directionality describes whether there is a clear dominant direction in the texture.

[0047] In a specific embodiment, the first texture feature parameter corresponding to the solder in the three-dimensional image is extracted by the gray level co-occurrence matrix algorithm: the contrast is 0.80, the energy is 0.90, the entropy is 0.50, and the correlation is 0.75. Then,

[0048] In this embodiment, the second texture feature vector detected is [0.85, 0.92, 0.45, 0.78]. The Euclidean distance calculation formula is: + + + =0.0063; ≈0.0794 The similarity is: Similarity

[0049] The similarity between the first texture feature and the second texture feature is 92.6%.

[0050] In practice, the present invention is carried out by detecting that the predicted dense areas and dispersed areas are not fused during the heating process. The texture features of the predicted dense areas and the predicted dispersed areas on both sides of the tearing surface 4 are analyzed and compared with the texture features generated by the downward vertical torque transmitted by the placement machine nozzle to determine whether the tearing surface 4 is generated by the downward vertical torque transmitted by the placement machine nozzle. If the two are consistent, the pressure value of the placement machine nozzle is adjusted accordingly to improve the electrical connectivity of the PCB board.

[0051] Specifically, the specific standard for determining pressure abnormality is based on the similarity of texture features. The pressure abnormality is determined to be abnormal when the downward vertical torque transmitted by the placement machine nozzle is greater than the preset torque. The first pressure value of the placement machine nozzle is extracted based on the second texture feature, and the first pressure value is adjusted to the preset pressure value.

[0052] The preset pressure value is 0.032MPa. When the first pressure value exceeds the preset pressure value within 0.0032MPa, the nozzle upward speed of the placement machine is adjusted to 90% of the current speed. When it exceeds 0.0032MPa, the nozzle upward speed of the placement machine is reduced by 10% for every 0.0016MPa exceeding 0.0016MPa. For example, the first pressure value of the placement machine nozzle currently extracted by the second texture feature is 0.035 MPa, and the current upward movement speed is 10 mm / s, which exceeds the preset pressure value by 0.003 MPa. After adjustment, the upward movement speed of the placement machine nozzle is 10 mm / s × 90% = 9 mm / s. For example, the first pressure value of the placement machine nozzle currently extracted by the second texture feature is 0.038 MPa, and the current upward movement speed is 10 mm / s, which exceeds the preset pressure value of 0.004 MPa. After adjustment, the upward movement speed of the placement machine nozzle is 10 mm / s×80%=8 mm / s.

[0053] Specifically, when the vertical distribution height of the solder calculated by the Z-axis coordinate of the three-dimensional image is greater than the preset distribution height, the heating rate of the outer portion 5 of the attachment area is increased to the first heating rate, and the heating rate of the inner portion of the attachment area is reduced to the second heating rate, so as to guide the solder 2 to flow outward through the temperature gradient, wherein, The attachment area is the three-dimensional space area of ​​the solder 2 of a single solder joint corresponding to the component patch 1, and is identified by the contact boundary between the solder 2 and the PCB substrate in the three-dimensional image.

[0054] In an implementation, the first heating rate is positively correlated with the vertical distribution height of the solder, and the second heating rate is negatively correlated with the vertical distribution height of the solder; The calculation method of the vertical distribution height is: The solder pixels in the Z-axis direction of the 3D image are threshold segmented, and the pixels with a height greater than 0.1 mm from the substrate surface are extracted, and their average Z-axis coordinates are calculated.

[0055] Specifically, the solder area within the range of the circumscribed circle with the center point of the resistor as the center and the line segment formed by the line connecting the center point of the resistor to any projected end point as the radius is the inner part 6 of the attachment area; the solder area from the edge of the resistor to the boundary of the PCB pad 3 is the outer part 5 of the attachment area.

[0056] Definition of the attachment area, which part of the outer and inner parts of the attachment area refer to In a specific embodiment, in the corresponding solder area, the average Z-axis coordinate of 1000 effective pixels is 0.32 mm, the preset distribution height = tile thickness × 1.5, that is, 0.2 mm × 1.5 = 0.3 mm, and since the measured vertical distribution height of 0.32 mm is greater than the preset distribution height of 0.3 mm, it is determined that there is a risk of accumulation of the outer solder 2, the first heating rate = the first proportional coefficient × the measured vertical distribution height, then the first heating rate = 10 × 0.32 = 3.2 ° C / s; the first heating rate = the second proportional coefficient / the measured vertical distribution height, then the second heating rate = 1 / 0.32 = 3.125 ° C / s, Increase the heating rate of the outer part of the attachment area to 3.2°C / s; The heating rate of the inner part of the attachment area is reduced to 3.125℃ / s, where The first proportional coefficient and the second proportional coefficient are experimental variables set according to the experiment. By selecting different measured vertical distribution heights (such as 0.2mm, 0.3mm, 0.4mm, etc., covering the possible accumulation risk range), the external heating rate corresponding to different proportional coefficients (such as 5, 8, 10, 12, etc.) is tested.

[0057] Specifically, the first heating rate is greater than the second heating rate.

[0058] In implementation, the present invention adjusts the heating rate when the vertical distribution height of the solder 2 calculated through the Z-axis coordinate of the three-dimensional image is greater than the preset distribution height, so that the temperature gradient guides the solder 2 to flow outward to compensate for the accumulation of solder 2 on the outside caused by excessive vertical torque of the placement machine nozzle.

[0059] Specifically, based on the inconsistency between the first texture feature and the second texture feature, that is, the similarity between the first texture feature and the second texture feature is less than 90%, the heating temperature of the dense area is increased and the heating temperature of the dispersed area is decreased.

[0060] In a specific embodiment, after the actual heating of the solder 2 is completed, the solder 2 is cooled by air circulation until the temperature of the solder 2 drops below 50° C.

[0061] Specifically, after forming the multi-layer PCB assembly board, the connection stability or power consumption detection of the Internet of Things communication module does not meet the requirements and is determined to be a bad situation, and the communication parameters are calibrated and the radio frequency circuit design is optimized. Among them, calibrating the communication parameters includes adjusting the transmission power of the communication module and optimizing the operating frequency of the communication module; optimizing the RF circuit design includes adjusting the impedance matching of the RF circuit and adding a shielding cover or a ground plane on the PCB board.

[0062] During implementation, the present invention verifies whether the key functions of the mobile air-conditioning panel are normal by performing key response tests, display drive tests, and connection stability tests of the Internet of Things communication module, ensuring that the key responses are sensitive, without delay or failure; verifies whether the display function of the mobile air-conditioning panel is normal, ensuring that the displayed content is clear, without flickering or misalignment; and verifies whether the Internet of Things communication module of the mobile air-conditioning panel can stably connect to the network, ensuring the reliability and real-time performance of data transmission.

[0063] Working process: Solder 2 is evenly spread on a multi-layer PCB to form a PCB attachment substrate. The PCB attachment substrate is then heated at the solder 2's spreading temperature to initially activate the solder 2. Component patches 1 are attached to corresponding pads 3 on the PCB attachment substrate using the placement machine's nozzle. The nozzle pressure is adjusted according to process requirements to ensure secure attachment of the components. The solder 2 on the pre-fixed PCB is then heated, melted, and cooled sequentially to simulate the actual soldering process. A 3D scanner is used to obtain several frames of 3D images of the solder 2 on the pad 3. Based on the 3D images, a dense area of ​​the solder 2 having a density greater than a first preset density and a dispersed area of ​​the solder having a density less than the first preset density at the melting temperature are determined. Based on the duration of the dense area and the dispersed area, a tearing surface 4 that may be generated in the heating process of the solder 2 is located. The texture features of the predicted dense area and dispersed area on both sides of the tearing surface 4 are extracted through the 3D images. The texture features generated by the downward vertical torque transmitted by the nozzle of the placement machine are simulated. The first texture feature is compared with the second texture feature. If they are consistent, it indicates that the downward vertical torque transmitted by the nozzle of the placement machine is too large. According to the second texture feature, the texture features are compared. The second texture feature extracts the first pressure value of the placement machine nozzle and adjusts it to a preset pressure value. The height of the heated solder 2 is detected based on the distribution area of ​​solder 2 with consistent texture features. The solder area within the circumscribed circle, centered at the center of the resistor and circumscribed by a line segment from the center of the resistor to any projected endpoint, is defined as the inner portion 6 of the attachment area. The solder area from the edge of the resistor to the edge of the PCB pad 3 is defined as the outer portion 5 of the attachment area. The heating rate of the outer portion 5 of the attachment area is increased to a first heating rate, while the heating rate of the inner portion 6 of the attachment area is reduced to a second heating rate, the first heating rate being greater than the second heating rate. The heating rate is adjusted when the vertical distribution height of the solder 2 calculated from the Z-axis coordinate of the three-dimensional image is greater than the preset distribution height. This temperature gradient guides the solder 2 to flow outward, compensating for the accumulation of solder 2 on the outer side caused by excessive vertical torque on the placement machine nozzle. The pre-fixed PCB is heated, melted, and cooled at a predetermined heating rate to ensure uniform distribution of solder 2. Using the optimized heating rate and nozzle pressure, the components are securely fixed to their corresponding positions on the pre-fixed PCB, forming a multi-layer PCB assembly. The multi-layer PCB assembly is bonded to the mobile air conditioner baseboard to form a complete mobile air conditioner panel. The panel's key functions are tested to ensure responsiveness, without delay or failure. The display's brightness, contrast, and refresh rate are tested to ensure clarity, without flicker or misalignment. The IoT communication module's connection stability and power consumption are tested. If these do not meet requirements, the communication parameters are calibrated and the RF circuit design is optimized.

[0064] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A manufacturing process for a mobile air-conditioning panel based on a multi-layer PCB, characterized in that: include: Spreading solder onto a multi-layer PCB to form a PCB attachment substrate; Attaching component patches to corresponding patch positions on the PCB attachment substrate by the nozzle of the patch machine to form a pre-fixed PCB board; Performing a melting and cooling test on the solder on the pre-fixed PCB board, and acquiring several frames of three-dimensional images of the solder on the pre-fixed PCB board; determining a dense area and a dispersed area according to the plurality of frames of three-dimensional images; Positioning a tearing-prone surface of the solder based on a duration of the dense region and a duration of the dispersed region; The texture characteristics of the dense and dispersed areas on both sides of the tear surface are compared with the texture characteristics generated during the component patch attachment process. If the texture features are consistent, it is determined that the attachment pressure generated by the nozzle is in an abnormal state, and the nozzle pressure is re-determined according to the abnormal state; Determine the heating rates of the outer portion and the inner portion of the attachment area according to the distribution height of the heated solder having consistent texture characteristics; The pre-fixed PCB is actually heated and cooled according to the heating rate to fix the components to the corresponding patch positions on the pre-fixed PCB to form a multi-layer PCB assembly; Laminating the multi-layer PCB assembly board to a mobile air conditioner substrate to form a mobile air conditioner panel; The heating parameters on both sides of the tearing surface are related to the duration.

2. The manufacturing process of a mobile air-conditioning panel based on a multi-layer PCB according to claim 1, characterized in that: The determining of the dense area and the scattered area according to the plurality of frames of three-dimensional images includes: Extracting solder density at a plurality of density sampling points arranged at equal intervals in the plurality of frames of three-dimensional images; Determine the largest closed three-dimensional area formed by connecting the first corresponding density sampling points that meet the solder density condition as the dense area; The entire solder three-dimensional space occupied by the second corresponding density sampling points that do not meet the solder density condition is determined as the scattered area.

3. The manufacturing process of a mobile air-conditioning panel based on a multi-layer PCB according to claim 2, characterized in that: The solder density condition is that the solder density at the density sampling point is greater than a preset density.

4. The manufacturing process of a mobile air-conditioning panel based on a multi-layer PCB according to claim 3, characterized in that: The tearing surface is positioned according to the duration of the dense area and the dispersed area at the melting temperature, wherein: The tearing-tendency surface is formed when the solder cools due to temperature gradient and heat dissipation difference, and the interface between the largest closed three-dimensional areas in the dense area and the dispersed area is the tearing-tendency surface.

5. The manufacturing process of a mobile air-conditioning panel based on a multi-layer PCB according to claim 4, characterized in that: The melting temperature is the temperature at which the solder on the pre-fixed PCB board is subjected to a melting cooling test.

6. The manufacturing process of a mobile air-conditioning panel based on a multi-layer PCB according to claim 5, characterized in that: The texture features of the predicted dense area and the predicted dispersed area on both sides of the tearing surface are compared with the texture features generated by the downward vertical torque transmitted by the nozzle of the placement machine, including extracting the first texture features of the predicted dense area and the predicted dispersed area through the three-dimensional image of the pre-fixed PCB board; obtaining the second texture features generated by the downward vertical torque transmitted by the simulated placement machine nozzle, wherein, If the similarity between the first texture feature and the second texture feature is greater than or equal to 90%, it is determined that the first texture feature and the second texture feature are consistent.

7. The manufacturing process of a mobile air-conditioning panel based on a multi-layer PCB according to claim 6, characterized in that: The specific standard for determining pressure abnormality is based on the similarity of texture features. The pressure abnormality is that the downward vertical torque transmitted by the placement machine nozzle is greater than the preset torque, which determines that the state of the placement machine nozzle is abnormal at this time. The first pressure value of the placement machine nozzle is extracted based on the second texture feature, and the first pressure value is adjusted to the preset pressure value.

8. The manufacturing process of a mobile air-conditioning panel based on a multi-layer PCB according to claim 7, characterized in that: When the vertical distribution height of the solder calculated by the Z-axis coordinate of the three-dimensional image is greater than the preset distribution height, the heating rate of the outer portion of the attachment area is increased to a first heating rate, and the heating rate of the inner portion of the attachment area is reduced to a second heating rate, so as to guide the solder to flow outward through the temperature gradient, wherein, The attachment area is the three-dimensional space area of ​​the solder of a single solder joint corresponding to the component patch, and is identified by the contact boundary between the solder and the PCB substrate in the three-dimensional image.

9. The manufacturing process of a mobile air-conditioning panel based on a multi-layer PCB according to claim 8, characterized in that: The first heating rate is greater than the second heating rate.

10. The manufacturing process of a mobile air-conditioning panel based on a multi-layer PCB according to claim 6, characterized in that: Based on the similarity between the first texture feature and the second texture feature being less than 90%, the heating temperature of the dense region is increased and the heating temperature of the dispersed region is decreased.

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