Method and device for determining preferential backflow surface, electronic equipment and storage medium

Abstract

The invention discloses a method for determining a preferential backflow surface. The method comprises the following steps: acquiring related information; the related information comprises printed board information related to reflow soldering and device information on the printed board; judging whether the obtained related information meets conditions set in a checking rule or not according to a sequence by utilizing a group of preset ordered checking rules; and when the condition set in any inspection rule is satisfied, determining the preferential backflow surface of the printed board according to the mode of determining the preferential backflow surface corresponding to the inspection rule. According to the invention, quality accidents, such as welding device scrapping, circuit board repairing or production line stopping, which are possibly caused by wrong selection of the preferential reflow surface can be reduced.

Description

Technical Field

[0001] The invention belongs to the field of printed circuit board processing, and in particular relates to a method, a device, an electronic device and a storage medium for determining a priority reflow surface. Background Art

[0002] With the continuous development of electronic technology, the application scope of PCB (Printed Circuit Board) is becoming more and more extensive. From the perspective of PCB electrical equipment, PCB can usually be divided into single-sided board and double-sided board. In the fields of consumer electronics, aerospace, automobile, etc., double-sided board is particularly common.

[0003] When mounting double-sided boards using SMT (Surface Mount Technology), the priority of reflow soldering the TOP side or BOTTOM side has a very important impact on soldering quality and cost. Wrong selection of the priority reflow side may lead to quality accidents such as scrapped soldered components, circuit board rework or production line shutdown. Among them, the TOP side refers to the top side of the PCB, also called the T side, and the BOTTOM side refers to the bottom side of the PCB, also called the B side.

[0004] At present, the priority reflow surface is determined mainly through the following three methods when SMT mounts double-sided boards:

[0005] The first method is to select the priority reflow surface based on the engineer's personal experience. For example, in order to avoid secondary reflow of core components, many engineers will prioritize the opposite side of the printed circuit board where the core components are located as the priority reflow surface.

[0006] The second type: the default B side or the side with fewer components is used as the priority reflow side;

[0007] The third method: Based on the product iteration, the previous welding process is used to select the priority reflow surface.

[0008] However, the first method mentioned above may lead to wrong choices due to the engineer's lack of personal experience; the second method is not applicable to some PCBs and may lead to wrong choices; the third method is limited to specific products and is not universal. Summary of the invention

[0009] In order to solve the above problems existing in the prior art, the present invention provides a method, device, electronic device and storage medium for determining a priority reflow surface.

[0010] The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0011] A method for determining a preferential reflow surface, comprising:

[0012] Obtaining relevant information; the relevant information includes: printed circuit board information related to reflow soldering and device information on the printed circuit board;

[0013] Using a set of preset orderly inspection rules, it is determined in order whether the obtained relevant information meets the conditions set in the inspection rules;

[0014] When the conditions set in any inspection rule are met, the priority reflow surface of the printed circuit board is determined according to the method of determining the priority reflow surface corresponding to the inspection rule.

[0015] The present invention also provides a device for determining a preferential reflux surface, comprising:

[0016] An acquisition module is used to acquire relevant information; the relevant information includes: printed circuit board information related to reflow soldering and device information on the printed circuit board;

[0017] A judgment module, used to use a set of preset ordered inspection rules to sequentially judge whether the obtained relevant information meets the conditions set in the inspection rules;

[0018] The determination module is used to determine the priority reflow surface of the printed circuit board according to the method of determining the priority reflow surface corresponding to the inspection rule when the conditions set in any inspection rule are met.

[0019] The present invention also provides an electronic device, comprising a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus;

[0020] The memory is used to store computer programs;

[0021] The processor is used to implement the method steps described in any of the above methods for determining a priority reflow surface when executing the computer program stored in the memory.

[0022] The present invention also provides a computer-readable storage medium, wherein a computer program is stored in the computer-readable storage medium. When the computer program is executed by a processor, the method steps described in any of the above methods for determining a priority reflow surface are implemented.

[0023] In the method for determining the priority reflow surface provided by the present invention, printed circuit board information related to reflow soldering and device information on the printed circuit board are obtained, and a set of preset orderly inspection rules are used to sequentially determine whether the obtained relevant information meets the conditions set in the inspection rules; when the conditions set in any inspection rule are met, the priority reflow surface of the printed circuit board is determined according to the method for determining the priority reflow surface corresponding to the inspection rule. The method comprehensively considers various aspects of information related to reflow soldering, and helps users choose a better welding sequence by setting orderly inspection rules, reducing quality accidents such as scrapping of welding devices, circuit board repair or production line shutdown that may be caused by incorrect selection of the priority reflow surface, thereby improving welding quality, shortening product cycle and saving manufacturing costs.

[0024] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a flow chart of a method for determining a preferential reflow surface provided by an embodiment of the present invention;

[0026] Figure 2 A long lead device is shown in ;

[0027] Figure 3 is a schematic diagram of a target range close to a conveying edge of a printed circuit board in an embodiment of the present invention;

[0028] Figure 4 is a flow chart of another method for determining a preferential reflow surface provided by an embodiment of the present invention;

[0029] FIG5( a ) shows the T surface of a printed circuit board;

[0030] FIG5( b ) shows side B of a printed circuit board;

[0031] Figure 6 is the relevant information obtained and provided by the embodiment of the present invention;

[0032] Figure 7 is a structural schematic diagram of a device for determining a preferential reflow surface provided by an embodiment of the present invention;

[0033] Figure 8 It is a structural schematic diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0035] In order to reduce quality accidents such as scrapped soldering components, circuit board rework or production line shutdown that may be caused by incorrect selection of a priority reflow surface, an embodiment of the present invention provides a method, device, electronic device and storage medium for determining a priority reflow surface.

[0036] First, the method for determining the preferential reflow surface provided by the embodiment of the present invention is described in detail.

[0037] like Figure 1 As shown, the method comprises the following steps:

[0038] S10: Obtain relevant information; the relevant information includes: printed circuit board information related to reflow soldering and device information on the printed circuit board.

[0039] Here, the printed circuit board information related to reflow soldering includes but is not limited to: printed circuit board size, printed circuit board thickness, device number on the printed circuit board, and device coordinates, etc. The device information on the printed circuit board related to reflow soldering includes but is not limited to: package information, package type, device model, pin spacing (Pitch), device size information, pin type, device structure information, solder ball composition, device weight, limit height, and printed circuit board surface information where the device is located, etc.

[0040] Among them, the device number, device coordinates, printed board size, printed board thickness, package information, device model, printed board surface information where the device is located, pitch, and package type can be obtained by reading the CAD data of the printed board. Device size information, pin type, device structure information, solder ball composition, device weight, and limit height can be obtained from the device specification sheet.

[0041] S20: Using a preset set of ordered inspection rules, determine in order whether the obtained relevant information meets the conditions set in the inspection rules.

[0042] The set of ordered inspection rules mentioned here is set according to the importance of the relevant information to be inspected in each inspection rule for determining the priority return surface. In other words, the relevant information to be inspected by the inspection rule at the front is more important for determining the priority return surface. If the inspection rule is skipped, there is a greater probability that the priority return surface selection will be wrong.

[0043] S30: When a condition set in any inspection rule is met, the priority reflow surface of the printed circuit board is determined according to the method of determining the priority reflow surface corresponding to the inspection rule.

[0044] It is understandable that each inspection rule includes not only the content of inspecting the printed board information and / or device information related to the rule, but also the content of determining the T side or B side of the printed board as the priority reflow surface according to the inspection result. Therefore, when it is found during the inspection process that a condition set in an inspection rule is met, the priority reflow surface of the printed board can be determined according to the method of determining the priority reflow surface corresponding to the inspection rule.

[0045] The method for determining the priority reflow surface provided by the embodiment of the present invention comprehensively considers various information related to reflow soldering, and helps users select a better soldering sequence by setting orderly inspection rules, thereby improving soldering quality, shortening product cycle, and saving manufacturing costs.

[0046] In one embodiment, see Figure 4 As shown, a set of ordered inspection rules used in step S20 includes, in sequence: a first inspection rule R1 and a second inspection rule R2.

[0047] The first inspection rule R1 is an inspection rule for plug-in devices on a printed circuit board, and the second inspection rule R2 is an inspection rule for complex packaged devices on a printed circuit board. Those skilled in the art are aware that complex packaged devices include BGA (Ball Grid Array), LGA (Land Grid Array), and QFN (Quad Flat No-leads) packaged devices.

[0048] The first inspection rule specifically includes: checking whether there are long-pin plug-in devices that need reflow soldering on the printed circuit board; if so, determining that the opposite side of the printed circuit board where the long-pin plug-in device is located is the priority reflow side; if not, continuing to execute the second inspection rule; wherein, the long-pin plug-in device is a plug-in device whose pins will be exposed on the printed circuit board surface after being inserted and soldered to the printed circuit board.

[0049] Specifically, first check the package information of the device on the printed circuit board to determine whether there is a plug-in device; if there is a plug-in device, manually judge the soldering process of the plug-in device based on the device conditions (whether it can be reflowed), equipment conditions (whether there is corresponding reflow equipment), and the corresponding soldering risk of the device (soldering quality). If the plug-in device requires reflow soldering, further obtain the size information of the device from the device specification sheet. If the length of the pin soldering area of ​​the device is greater than the thickness of the printed circuit board, that is, the device pin will be exposed on the printed circuit board surface after the plug-in device is inserted into the printed circuit board for soldering, then determine that the opposite side of the printed circuit board surface where the long-pin plug-in device is located is the priority reflow surface. Among them, the thickness of the printed circuit board can be obtained from the CAD data of the printed circuit board; the length of the pin soldering area = pin length - limit height, the pin length (such as Figure 2The limit height can be obtained from the device data sheet.

[0050] The second inspection rule specifically includes: checking whether there is a target type device on one and only one side of the printed circuit board; among them, BGA (Ball Grid Array) devices, LGA (Land Grid Array) devices and QFN (Quad Flat No-leads) devices are all target type devices; if there is a target type device on one and only one side of the printed circuit board, the opposite side of the side is determined as the priority reflow side.

[0051] Specifically, check whether the package type of the device on the printed circuit board includes the above-mentioned target type device. If there is only one target type device, select the opposite side of the printed circuit board where the target type device is located as the priority reflow side; if there are multiple target type devices, further check whether the printed circuit board surfaces where these target type devices are located are T sides or B sides; if these target type devices are all located on one side of the printed circuit board, determine that the opposite side of this side is the priority reflow side.

[0052] In addition, if the condition that there is a target type device on one and only one side of the printed circuit board is not met, one way is to continue to use the existing method to select the priority reflow surface. However, it should be noted that since the possibility of incorrect selection of the priority reflow surface due to long-pin plug-in devices has been eliminated at this time, and the possibility of incorrect selection of the priority reflow surface due to the target type device has also been greatly reduced, compared with the existing method, part of the risk has been avoided and the accuracy of selecting the priority reflow surface has been improved.

[0053] Or, in one embodiment, continue to see Figure 4 As shown, when the condition that there is a target type device on one and only one side of the printed circuit board is not met, the set of ordered inspection rules used in step S20 may also include: a third inspection rule R3 arranged after the second inspection rule R2; the third inspection rule R3 is an inspection rule about the device pin spacing (Pitch) on the printed circuit board.

[0054] The third inspection rule specifically includes: checking whether there is a device on the printed circuit board whose pin pitch is less than or equal to the preset pin pitch; if so, determining that the opposite side of the printed circuit board where the device is located is the priority reflow side.

[0055] Specifically, the pitch information of the device on the printed circuit board is checked to find the device whose pitch is less than or equal to the preset pin pitch; when there is a device whose pitch is less than or equal to the preset pin pitch on the printed circuit board, the opposite side of the printed circuit board where the device is located is determined as the priority reflow surface. The preset pin pitch can be 0.25mm to 0.4mm.

[0056] In addition, if there are no devices with pitch less than or equal to the preset pin spacing on the printed circuit board, one way is to continue to use the existing method to select the priority reflow surface. However, it should be noted that at this time, the possibility of incorrect selection of the priority reflow surface due to devices with smaller pitches has been further eliminated. Therefore, compared with the existing method, more risks have been avoided and the accuracy of selecting the priority reflow surface has been further improved.

[0057] Or, in one embodiment, continue to see Figure 4 As shown, when there is no device on the printed circuit board whose pin pitch Pitch is less than or equal to the preset pin pitch, the set of ordered inspection rules used in step S20 may also include: a fourth inspection rule R4 arranged after the third inspection rule R3; the fourth inspection rule R4 is an inspection rule about the weight ratio of the devices on the printed circuit board.

[0058] The fourth inspection rule specifically includes: checking whether there are components on the printed board that do not meet the weight ratio requirements; if there are components that do not meet the weight ratio requirements, determining the opposite side of the printed board where the component is located as the priority reflow side;

[0059] Among them, weight ratio = device weight / effective welding area of ​​the bottom surface of the device; the method for obtaining the effective welding area of ​​the bottom surface of the device can be referred to the method for obtaining the effective welding area of ​​the bottom surface in the patent application document with application number 202010059830.7 and invention name “Simulation method, simulation device, electronic device and storage medium for welding tension”, which will not be repeated in the embodiments of the present invention.

[0060] The above weight ratio requirements include:

[0061] The weight ratio of chip components is ≤0.075g / mm 2 ;

[0062] The weight ratio of wing-shaped lead devices is ≤0.300g / mm 2 ;

[0063] Weight ratio of J-shaped lead device ≤ 0.200g / mm 2 ;

[0064] The weight ratio of the surface array device is ≤0.100g / mm 2 ;

[0065] The weight ratio of the module device is ≤0.110g / mm 2 .

[0066] In addition, when there are no components on the printed circuit board that do not meet the weight ratio requirements, one way is to continue to use the existing method to select the priority reflow surface. However, it should be noted that at this time, the possibility of incorrect selection of the priority reflow surface due to components with excessive weight ratios has been further eliminated. Therefore, compared with the existing method, more risks have been avoided and the accuracy of selecting the priority reflow surface has been further improved.

[0067] Or, in one embodiment, continue to see Figure 4 As shown, when there are no components on the printed circuit board that do not meet the weight ratio requirements, the set of ordered inspection rules used in step S20 may also include: a fifth inspection rule R5 arranged after the fourth inspection rule R4; the fifth inspection rule R5 is an inspection rule regarding the conveying direction of the printed circuit board during reflow soldering.

[0068] The fifth inspection rule specifically includes: when the printed circuit board does not use a tin-printed patch reflow tray to assist in soldering, check whether there is at least one device within a target range of d mm from the conveying edge of the printed circuit board; 3≤d<7, preferably d=5; if there are devices within the target range and at least one device is located on the same side of the printed circuit board, determine that the opposite side of the side is the priority reflow side.

[0069] Specifically, it is manually determined whether the printed circuit board uses a tin-printed patch reflow tray to assist in soldering. If not, it is further checked whether there are devices within the target range of dmm close to the conveying edge of the printed circuit board. For the same PCB board, d takes the same value when checking the T side and the B side. If there are devices within the target range and the existing devices are only located on one side of the printed circuit board, the opposite side of the side is determined as the priority reflow side.

[0070] It can be understood that the target range includes: on the two printed board surfaces, 4 rectangular areas formed by advancing d mm inward starting from the printed board conveying edge; see Figure 3 As shown in the figure, Direction indicates the conveying direction of the printed board, L1 and L2 are the two conveying edges of the printed board, and the upper and lower shaded rectangular areas are the two target ranges of the printed board T surface. There are also two corresponding rectangular areas on the printed board B surface that also belong to the target range. Figure 3 This is a top view and therefore not shown.

[0071] In an optional implementation, checking whether there is at least one device on the printed board within a target range of d millimeters from the transmission edge of the printed board may include:

[0072] (1) Determine the limit frame coordinates of the printed board according to the size of the printed board and the relative coordinate origin;

[0073] See also Figure 3 As shown, the relative coordinate origin of the printed board is p1 (xmin, ymin). According to the size of the printed board, the diagonal point p2 (xmax, ymax) of p1 can be obtained, and the limit frame coordinates of the entire printed board can be calculated.

[0074] (2) Determine the printed board conveying edge according to the conveying direction of the printed board during reflow soldering, and determine the coordinates of the printed board conveying edge according to the limit frame coordinates;

[0075] It can be understood that the edge of the printed board parallel to the conveying direction of the printed board is the conveying edge of the printed board; the coordinates of two conveying edges of the printed board are selected from the coordinates of the limit frame.

[0076] (3) Determine the target range based on the coordinates of the printed board transfer edge;

[0077] For example, Figure 3 As shown, the printed board conveying side is the long side of the printed board, and the inspection range includes Figure 3 rect1 and rect2 in the figure and the rectangular areas of equal size directly below them; where rect1 is a rectangular area with points rp1(xmin,ymax-d), rp2(xmin,ymax), rp3(xmax,ymax) and rp4(xmax,ymax-d) as the four corner endpoints, and rect2 is a rectangular area with points rp5(xmin,ymin), rp6(xmin,ymin+d), rp7(xmax,ymin+d) and rp8(xmax,ymin) as the four corner endpoints.

[0078] The method of determining the target range when the conveying side of the printed circuit board is the short side of the printed circuit board is similar, and will not be repeated here.

[0079] (4) Check whether there is at least one device within the target range.

[0080] Specifically, for each device on the printed board, determine whether the projection outline coordinates of the device on the printed board surface fall within the target range; if the projection outline coordinates of a device on the printed board surface are within the target range, then determine that the device exists within the target range.

[0081] Among them, for a polygonal device, the method of judging whether the projection outline coordinates of the polygonal device on the printed circuit board fall within the target range includes: judging whether the projection endpoint coordinates of the projection outline coordinates of the polygonal device fall within the target range. This can improve the judgment efficiency of the polygonal device.

[0082] For devices such as circles or ellipses, since there are no projected endpoint coordinates in their projected contour coordinates, it can be determined by judging whether the projected contour coordinates on the printed circuit board surface fall within the target range.

[0083] See Figure 3 As shown, let the projected contour coordinates of the devices existing within the target range be Pi (i = 1, 2, ……, n), where n is the number of points of the projected contour coordinates. For devices without projected endpoint coordinates, it is successively judged whether each Pi falls within rect1, rect2 or the rectangular areas of the same size directly below them; for example, for rect1, if Pi.x > xmin and Pi.x < xmax and Pi.y > ymax - d and Pi.y < ymax, then the point Pi is within rect1, otherwise Pi is not within rect1; similarly, for rect2, if Pi.x > xmin and Pi.x < xmax and Pi.y > ymin and Pi.y < ymin + d, then the point Pi is within rect2, otherwise Pi is not within rect2. Here, Pi.x is the abscissa of Pi, and Pi.y is the ordinate of the coordinate point Pi.

[0084] For polygonal devices, assuming that the projected endpoint coordinates in their projected contour coordinates are Pj (j ∈ i), it is only necessary to judge whether each Pj falls within rect1, rect2 or the rectangular areas of the same size directly below them.

[0085] In addition, when the printed circuit board uses a solder paste reflow tray to assist in soldering, or when the printed circuit board does not use a solder paste reflow tray to assist in soldering and there are no devices within a range of d millimeters from the transfer edge of the printed circuit board, or when the printed circuit board does not use a solder paste reflow tray to assist in soldering and there are devices within the target range of d millimeters from the transfer edge of the printed circuit board but the devices are on different sides of the printed circuit board, one way is to continue to use the existing method to select the priority reflow side. However, it should be noted that at this time, the possibility of incorrect selection of the priority reflow side caused by the existence of devices close to the transfer edge of the printed circuit board has been further eliminated. Therefore, compared with the existing method, more risks have been further avoided, and the accuracy of selecting the priority reflow side has been improved.

[0086] Or, in one embodiment, continue to refer to Figure 4As shown, when the printed board uses a tin-printed patch reflow tray to assist in soldering, or when the printed board does not use a tin-printed patch reflow tray to assist in soldering and there is no device on the printed board within a range of d mm from the conveying edge of the printed board, or when the printed board does not use a tin-printed patch reflow tray to assist in soldering and there are devices on the printed board within a target range of d mm from the conveying edge of the printed board but the devices are located on different sides of the printed board, the set of ordered inspection rules used in step S20 may also include: a sixth inspection rule R6 arranged after the fifth inspection rule R5; the sixth inspection rule R6 is an inspection rule for WLCSP (Wafer Level Chip Scale Packaging) devices.

[0087] The sixth inspection rule specifically includes: checking whether there is a WLCSP device on the printed board; if there is a WLCSP device on the printed board, determining that the printed board surface where the WLCSP device is located is the priority reflow surface.

[0088] In addition, when there is no WLCSP device on the printed circuit board, one way is to continue to use the existing method to select the priority reflow surface. However, it should be noted that at this time, the possibility of incorrect selection of the priority reflow surface due to the presence of the WLCSP device has been further eliminated. Therefore, compared with the existing method, more risks have been avoided and the accuracy of selecting the priority reflow surface has been further improved.

[0089] Or, in one embodiment, continue to see Figure 4 As shown, when there is no WLCSP device on the printed circuit board, the set of ordered inspection rules used in step S20 may also include: a seventh inspection rule R7 arranged after the sixth inspection rule R6; the seventh inspection rule R7 is an inspection rule for the solder ball component of the device on the printed circuit board.

[0090] The seventh inspection rule specifically includes: checking whether there is a BGA device on the printed circuit board whose solder ball component silver content is greater than a preset percentage; if there is a BGA device on the printed circuit board whose solder ball component silver content is greater than a preset percentage, determining the printed circuit board surface where the BGA device is located as the priority reflow surface. The preset percentage is preferably set to 3%.

[0091] In addition, when there is no BGA device on the printed circuit board whose silver content of solder ball components is greater than the preset percentage, one way is to continue to use the existing method to select the priority reflow surface. However, it should be noted that at this time, the possibility of incorrect selection of the priority reflow surface due to the presence of long-pin plug-in devices has been eliminated, and the possibility of incorrect selection of the priority reflow surface due to the presence of target type devices has been greatly reduced. The possibility of incorrect selection of the priority reflow surface due to the presence of devices with smaller pitches has been eliminated, and the possibility of incorrect selection of the priority reflow surface due to the presence of devices with excessive weight ratios has been eliminated. The possibility of incorrect selection of the priority reflow surface due to the presence of devices close to the transmission edge of the printed circuit board has been eliminated. The possibility of incorrect selection of the priority reflow surface due to the presence of WLCSP devices has been eliminated. The possibility of incorrect selection of the priority reflow surface due to the presence of BGA devices with excessive silver content in solder balls has been eliminated. Therefore, compared with the existing method, many risks have been greatly avoided and the accuracy of selecting the priority reflow surface has been improved.

[0092] The beneficial effects of the embodiments of the present invention are described below with specific examples.

[0093] Figure 5(a) shows the T side of a printed circuit board, and Figure 5(b) shows the B side of the printed circuit board. By reading the CAD data of the printed circuit board and the specifications of each device on the printed circuit board, the relevant information obtained is as follows: Figure 6 shown.

[0094] Example 1: Using the embodiment of the present invention Figure 4 The method shown in determines the preferential reflow surface. The specific process is as follows:

[0095] Using the first check rule Figure 6 The relevant information in the device package information is checked. It is found that there is a plug-in device on the printed circuit board, and its position number is J5. The plug-in device needs to use reflow soldering, and its pin welding area length = pin length - limit height = 1.5-0.2 = 1.3. The thickness of the printed circuit board is 1.5, 1.3 < 1.5. Therefore, after the plug-in device is inserted into the printed circuit board for soldering, the device pin will not be exposed on the printed circuit board surface, and the conditions in the first inspection rule are not met.

[0096] Continue to use the second check rule to Figure 6 The relevant information in the PCB is checked. By checking the device package type, it is found that there are two BGA packaged devices on the printed circuit board (U3 and U5). One of these two BGA devices is on the T side of the printed circuit board, and the other is on the B side of the printed circuit board. They are not on the same side, so they do not meet the conditions in the second inspection rule.

[0097] Continue to use the third check rule to Figure 6Check the relevant information in the Pitch information of the device at each bit number as follows:

[0098] R35: Pitch=1.524mm>0.35mm,

[0099] R14: Pitch=1.524mm>0.35mm,

[0100] J5: Pitch=1.27mm>0.35mm,

[0101] U11: Pitch=0.498mm>0.35mm,

[0102] U3: Pitch=0.4mm>0.35mm,

[0103] D12: Pitch=3.5mm>0.35mm,

[0104] D10: Pitch=1.626mm>0.35mm,

[0105] U5: Pitch=0.399mm>0.35mm;

[0106] It can be seen that there is no device with Pitch ≤ 0.35 on the printed circuit board, so the condition in the third check rule is not met.

[0107] Continue to use the fourth inspection rule to Figure 6 Check the relevant information in the , and find that the pin type and weight of the device at each position are as follows:

[0108] Chip device R35: weight ratio = 0.0065 / 1.5 = 0.0043 < 0.075 g / mm 2 ;

[0109] Chip device R14: weight ratio = 0.0065 / 1.5 = 0.0043 < 0.075 g / mm 2 ;

[0110] Wing-shaped lead device U11: weight ratio = 0.08 / 2.16 = 0.037 < 0.300 g / mm 2 ;

[0111] Area array device U3: weight ratio = 0.18 / 2.7 = 0.067 < 0.100 g / mm 2 ;

[0112] Chip device D12: weight ratio = 0.0086 / 2.1 = 0.004 < 0.075 g / mm 2 ;

[0113] Chip device D10: weight ratio = 0.0086 / 2.1 = 0.004 < 0.075 g / mm 2 ;

[0114] Area array device U5: weight ratio = 0.14 / 2.9 = 0.048 < 0.100 g / mm 2 ;

[0115] It can be seen that the weight ratios of the components on the printed circuit board all meet the weight ratio requirements and therefore do not meet the conditions in the fourth inspection rule.

[0116] Continue to use the fifth inspection rule to Figure 6 The relevant information in the test is checked. First, it is manually determined that the product does not need to use a reflow tray to assist soldering, so a further check is made to see if there is a device within the target range of d = 5mm near the printed circuit board conveying edge (the printed circuit board conveying edge is the long side of the printed circuit board).

[0117] The target scope includes:

[0118] A rectangular area with four points rp1(0,160), rp2(0,165), rp3(314,165), and rp4(309,160) as the four corner endpoints;

[0119] And the rectangular area with rp5(0,0), rp6(0,5), rp7(314,5) and rp8(314,0) as the four corner points.

[0120] The inspection results are as follows:

[0121] R35: coordinates (150.480, 70.035), 0<X=150.480<314, 5<Y=70.035<160,

[0122] R14: coordinates (152.020, 70.035), 0<X=152.020<314, 5<Y=70.035<160,

[0123] J5: coordinates (70.128, 130.356), 0<X=70.128<314, 5<Y=130.356<160,

[0124] U11: coordinates (62.858, 150.135), 0<X=62.858<314, 5<Y=150.135<160,

[0125] U3: coordinates (152.021, 75.179), 0<X=152.021<314, 5<Y=75.179<160, D12: coordinates (275.485, 41.115), 0<X=275.485<314, 5<Y=41.115<160,

[0126] D10: coordinates (260.040, 142.595), 0<X=260.040<314, 5<Y=142.595<160,

[0127] U5: coordinates (200.435, 89.720), 0<X=200.435<314, 5<Y=89.720<160.

[0128] It can be seen that all devices are not within the target range and therefore do not meet the conditions in the fifth inspection rule.

[0129] Continue to use the sixth inspection rule to Figure 6 The relevant information in the inspection was checked and no WLCSP device was found. Therefore, the conditions in the sixth inspection rule were not met.

[0130] Continue to use the seventh inspection rule to Figure 6 The relevant information in the inspection was checked, and by checking the device package type, it was found that there were BGA devices with position numbers U3 and U5 respectively; after checking the specifications of the two BGA devices, it was found that the printed circuit board surface where U5 was located was the T surface, and the content of U5 solder ball component was less than 3%, which did not meet the conditions in the seventh inspection rule; the device model of U3 was BGA515-CBB, and the silver content of its solder ball component was greater than the preset percentage of 3%, which met the conditions in the seventh inspection rule, so the T surface where U3 was located was taken as the priority reflow surface.

[0131] Example 2: For the printed circuit boards shown in Figures 5(a) and 5(b), an engineer was invited to select the priority reflow surface. Based on his personal experience, the engineer believed that there was a core device with a relatively large BGA package on the printed circuit board. The device model was BGA515-CBB and the position number was U3. The device was located on the T side of the printed circuit board. Therefore, in order to avoid secondary reflow of U3, the engineer selected the B side as the priority reflow surface.

[0132] Example 3: For the printed circuit boards in FIG. 5( a ) and FIG. 5( b ), a method commonly used in the prior art is adopted, and the B side with a smaller number of components is used as the priority reflow side by default.

[0133] It can be seen that the priority reflow surface determined in Examples 2 and 3 is different from that in the embodiment of the present invention. In the subsequent production inspection, it was found that U3 had a large number of solder short circuit problems. This is mainly because the silver content of the solder ball component of U3 is greater than 3%, and the two existing methods used in Examples 2 and 3 failed to effectively avoid the occurrence of this quality problem, which shows that Figure 4 The effectiveness of the method shown.

[0134] In another example, assuming that the device U3 in Figure 5(a) is located on the B side of the printed circuit board, U3 needs to use reflow soldering and the length of its pin welding area is greater than the thickness of the printed circuit board, then according to the method of defaulting to the B side or the side with fewer devices as the priority reflow side in the prior art, the B side should be selected as the priority reflow side; and using the embodiment of the first inspection rule + the second inspection rule in the embodiment of the present invention to determine the priority reflow side, the T side opposite to the B side where U3 is located is determined as the priority reflow side, which can avoid the problem of loose pins of U3 caused by reflowing the B side first and then the T side.

[0135] The above examples can illustrate that the method for determining the priority reflow surface provided in the embodiments of the present invention can effectively help users select a better welding sequence, reduce quality accidents such as scrapped welding components, circuit board rework or production line shutdown caused by incorrect selection of the priority reflow surface, thereby improving welding quality, shortening product cycle and saving manufacturing costs.

[0136] Corresponding to the above-mentioned method for determining a priority reflow surface, an embodiment of the present invention further provides a device for determining a priority reflow surface, which is applied in an electronic device, which may be a desktop computer, a portable computer, a smart mobile terminal, a server, etc.

[0137] like Figure 7 As shown, the device for determining the priority reflux surface provided by the embodiment of the present invention includes:

[0138] The acquisition module 1 is used to acquire relevant information; the relevant information includes: printed circuit board information related to reflow soldering and device information on the printed circuit board;

[0139] The judgment module 2 is used to use a set of preset orderly inspection rules to sequentially judge whether the obtained relevant information meets the conditions set in the inspection rules;

[0140] The determination module 3 is used to determine the priority reflow surface of the printed circuit board according to the method of determining the priority reflow surface corresponding to the inspection rule when the conditions set in any inspection rule are met.

[0141] Regarding the acquisition module 1, in one implementation, the acquisition module 1 may be a configuration file, and the user configures the printed board information related to reflow soldering and the device information on the printed board into the file, and the acquisition module 1 may acquire the relevant information. In another implementation, the acquisition module 1 may be a computer program that automatically reads CAD data and device specifications, that is, the acquisition module 1 may automatically read the CAD data of the printed board and the device specifications of the devices on the printed board.

[0142] Regarding the judgment module 2, when it executes the inspection rules in sequence, if it encounters a situation where manual judgment is required on whether the plug-in device needs reflow soldering and the computer cannot automatically judge, the judgment module 2 can pop up a prompt and the user can select a specific judgment result.

[0143] Regarding the determination module 3, the finally determined priority reflow surface may be notified to the user in the form of text or images.

[0144] The embodiment of the present invention further provides an electronic device, such as Figure 8 As shown, it includes a processor 801, a communication interface 802, a memory 803 and a communication bus 804, wherein the processor 801, the communication interface 802, and the memory 803 communicate with each other through the communication bus 804.

[0145] Memory 803, used for storing computer programs;

[0146] The processor 801 is used to implement the method steps described in any of the above methods for determining the priority reflow surface when executing the program stored in the memory 803.

[0147] The communication bus 804 mentioned in the above electronic device can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The communication bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is used in the figure, but it does not represent that there is only one bus or one type of bus.

[0148] The communication interface 802 is used for communication between the above electronic device and other devices.

[0149] The memory 803 may include a random access memory (RAM) or a non-volatile memory (NVM), such as at least one disk memory. Optionally, the memory may also be at least one storage device located away from the aforementioned processor.

[0150] The above-mentioned processor 801 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0151] The present invention also provides a computer-readable storage medium in which a computer program is stored, and when the computer program is executed by a processor, the method steps described in any of the above methods for determining a priority reflow surface are implemented.

[0152] Optionally, the computer-readable storage medium may be a non-volatile memory (NVM), such as at least one disk memory.

[0153] Optionally, the computer-readable memory may also be at least one storage device located away from the aforementioned processor.

[0154] In yet another embodiment of the present invention, a computer program product comprising instructions is provided, which, when executed on a computer, enables the computer to execute the method steps of any of the above methods for determining a preferential reflow surface.

[0155] It should be noted that, for the device / electronic device / storage medium / computer program product embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiments.

[0156] It should be noted that the terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein.

[0157] In the description of the present invention, the word “comprising” does not exclude other components or steps, “a” or “an” does not exclude a plurality of components, and “plurality” means two or more than two, unless otherwise clearly defined.

[0158] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A method for determining a preferential reflow surface, characterized in that: include: Obtain relevant information; The relevant information includes: printed board information related to reflow soldering and device information on the printed board; Using a set of preset orderly inspection rules, it is determined in order whether the obtained relevant information meets the conditions set in the inspection rules; When the conditions set in any inspection rule are met, the priority reflow surface of the printed circuit board is determined according to the method of determining the priority reflow surface corresponding to the inspection rule.

2. The method according to claim 1, characterized in that The set of ordered inspection rules includes, in sequence: a first inspection rule and a second inspection rule; The first inspection rule includes: Check whether there is a long-pin plug-in device that needs reflow soldering on the printed board; if so, determine that the opposite side of the printed board where the long-pin plug-in device is located is the priority reflow side; if not, continue to execute the second inspection rule; wherein the long-pin plug-in device is a plug-in device whose pins will be exposed on the printed board surface after being inserted and soldered to the printed board; The second inspection rule includes: Check whether there is a target type device on one and only one side of the printed circuit board; among them, BGA devices, LGA devices and QFN devices are all target type devices; If there is a target type device on one and only one side of the printed circuit board, the opposite side of this side is determined as the priority reflow side.

3. The method according to claim 2, characterized in that When the condition that there is a target type device on one and only one side of the printed board is not satisfied, the set of ordered inspection rules further includes: a third inspection rule arranged after the second inspection rule; The third inspection rule includes: Check whether there are devices on the printed circuit board whose pin pitch is less than or equal to the preset pin pitch; If so, determine that the opposite side of the printed circuit board where the device is located is the priority reflow side.

4. The method according to claim 3, characterized in that When there is no device on the printed circuit board whose pin pitch Pitch is less than or equal to the preset pin pitch, the set of ordered inspection rules further includes: a fourth inspection rule arranged after the third inspection rule; The fourth inspection rule includes: Check whether there are any components on the printed circuit board that do not meet the weight ratio requirements; If there is a component that does not meet the weight ratio requirement, determine the opposite side of the printed board where the component is located as the priority reflow side; Among them, weight ratio = device weight / effective welding area of ​​device bottom surface; The weight ratio requirements include: The weight ratio of chip components is ≤0.075g / mm 2 ; The weight ratio of wing-shaped lead devices is ≤0.300g / mm 2 ; Weight ratio of J-shaped lead device ≤ 0.200g / mm 2 ; The weight ratio of the surface array device is ≤0.100g / mm 2 ; The weight ratio of the module device is ≤0.110g / mm 2 .

5. The method according to claim 4, characterized in that When there are no components on the printed board that do not meet the weight ratio requirement, the set of ordered inspection rules further includes: a fifth inspection rule arranged after the fourth inspection rule; The fifth inspection rule includes: When the printed board is not soldered with a solder paste reflow tray, check whether there is at least one device within the target range of d mm from the printed board conveying edge; 3≤d<7; If there are devices within the target range and the at least one device is located on the same side of the printed circuit board, the side opposite to the side is determined as the priority reflow side.

6. The method according to claim 5, characterized in that The step of checking whether there is at least one device on the printed board within a target range of d mm from the transmission edge of the printed board comprises: Determine the limit frame coordinates of the printed board according to the size of the printed board and the relative coordinate origin; Determining the conveying edge of the printed board according to the conveying direction of the printed board during reflow soldering, and determining the coordinates of the conveying edge of the printed board according to the limit frame coordinates; The target range is determined according to the coordinates of the printed board conveying edge; the target range includes: on the two printed board surfaces, four rectangular areas formed by advancing d mm inward starting from the coordinates of the printed board conveying edge; Checking whether there is at least one device within the target range.

7. The method according to claim 6, characterized in that The checking whether there is at least one device within the target range comprises: For each device on the printed board, determining whether the projection outline coordinates of the device on the printed board surface fall within the target range; If the projection outline coordinates of a device on the printed circuit board are within the target range, it is determined that the device exists within the target range; Wherein, for a polygonal device, determining whether its projection outline coordinates on a printed circuit board surface fall within the target range includes: determining whether the projection endpoint coordinates in the projection outline coordinates of the polygonal device fall within the target range.

8. The method according to any one of claims 5 to 7, characterized in that: When the printed board is soldered with a tin-printed patch reflow tray, or when the printed board is not soldered with a tin-printed patch reflow tray, and there is no device on the printed board within a range of d millimeters from the conveying edge of the printed board, or when the printed board is not soldered with a tin-printed patch reflow tray, and there is a device on the printed board within a target range of d millimeters from the conveying edge of the printed board but the device is located on a different side of the printed board, the set of ordered inspection rules further includes: a sixth inspection rule arranged after the fifth inspection rule; The sixth inspection rule comprises: Check whether there is a WLCSP device on the printed circuit board; If there is a WLCSP device on the printed board, the printed board surface where the WLCSP device is located is determined as the priority reflow surface.

9. The method according to claim 8, characterized in that When there is no WLCSP device on the printed circuit board, the set of ordered inspection rules further includes: a seventh inspection rule arranged after the sixth inspection rule; The seventh inspection rule includes: Check whether there are BGA devices on the printed circuit board whose solder ball components contain more silver than the preset percentage; If there is a BGA device on the printed board whose solder ball component has a silver content greater than a preset percentage, the printed board surface where the BGA device is located is determined to be the priority reflow surface.

10. A device for determining a preferential reflow surface, characterized in that: include: An acquisition module is used to obtain relevant information; The relevant information includes: printed board information related to reflow soldering and device information on the printed board; A judgment module, used to use a set of preset ordered inspection rules to sequentially judge whether the obtained relevant information meets the conditions set in the inspection rules; The determination module is used to determine the priority reflow surface of the printed circuit board according to the method of determining the priority reflow surface corresponding to the inspection rule when the conditions set in any inspection rule are met.

11. An electronic device, characterized in that: It includes a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other through the communication bus; The memory is used to store computer programs; The processor is used to implement the method steps described in any one of claims 1 to 9 when executing the computer program stored in the memory.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method steps of any one of claims 1 to 9 are implemented.

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