Surface mounting method of large-size core board

Abstract

The invention discloses a mounting method for a large-size core board, and the method comprises the following steps: S1, placing the large-size core board on a core board tray, and determining the process direction of the core board tray; s2, performing tin coating on the semicircular bonding pad on the PCB mainboard by using the perforated steel mesh; s3, determining a suction recognition direction, segmenting the image according to the appearance characteristics of the large-size core board, and positioning, recognizing and pasting the large-size core board; and S4, performing reflow soldering and automatic optical detection on the large-size core board and the PCB mainboard. According to the invention, the process direction of the large-size core board is determined through the core board tray, the side edge of the large-size core board is coated with tin by using the perforated steel mesh, and then the suction identification direction is determined, so that the mounting of the large-size core board is realized; meanwhile, the printed tin amount of the large-size core board is guaranteed through the perforated steel mesh; the method is easy to operate and worthy of vigorous application and popularization.

Description

Technical Field

[0001] The invention belongs to the technical field of SMT production and manufacturing, and in particular relates to a mounting method for a large-size core board. Background Art

[0002] With the development of the display chip manufacturing industry, high-density, multi-level circuit designs have emerged. In this case, more layers of PCB boards are needed to meet the needs of wiring and signal transmission. Generally speaking, the core board PCB needs to adopt an 8-12-layer board design to ensure circuit performance, and such a design can provide good heat dissipation and current carrying capacity. However, such a design will also make the PCB board of the peripheral circuit too wasteful. Subsequently, a new type of PCB board appeared in the industry: the core board was designed as a sub-board with 8-12 layers, and the peripheral circuit adopted a 4-layer board design. However, for large-size core boards, such a design also has problems: during the patch process, the size of the core module board is larger than the normal patch specification range of the patch equipment; the core module board welding tin height requirements are strict. In addition, the mounting process of large-size core boards in the prior art is complicated, and it is not convenient to use in practice. Summary of the invention

[0003] In view of this, the purpose of the present invention is to provide a mounting method for a large-size core board, which solves the problem that the large-size core board cannot be mounted in the prior art.

[0004] In order to achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] A method for mounting a large-size core board comprises the following steps:

[0006] S1, placing the large-size core board on a core board tray, and determining the process direction of the core board tray;

[0007] S2, using a perforated steel mesh to tin the semicircular pads on the PCB main board;

[0008] S3, determining the absorption and identification direction, and segmenting the image according to the appearance characteristics of the large-size core board, and then positioning, identifying and pasting the large-size core board;

[0009] S4, reflow soldering and automatic optical inspection of large-size core boards after mounting.

[0010] In the above scheme, the short side direction of the large-size core board in S1 is the X-axis, and the process direction of the core board tray is the X-axis direction.

[0011] In the above solution, the dimension of the core board tray in the X-axis direction is less than 70 mm.

[0012] In the above scheme, in S2, the specific method of tinning is: applying solder paste on the surface of the perforated steel mesh, and transferring the solder paste to the semicircular pads of the PCB mainboard.

[0013] In the above scheme, in S2, the volume of tin in the perforated steel mesh>the volume requirement of tin in the semicircular pad of the PCB mainboard×70%.

[0014] In the above scheme, the absorption and identification direction in S3 is the X-axis direction.

[0015] In the above scheme, the symmetrical corners of the large-size core board are captured at least twice during positioning and identification in S3.

[0016] In the above scheme, the absorption recognition angle is set to 0°, and the patch angle is also set to 0°.

[0017] In the above scheme, in S4, the reflow soldering process is specifically: the solder paste in the tin tray is heated and melted by a reflow soldering furnace, thereby combining the large-size core board and the semicircular solder pad on the PCB main board.

[0018] In the above scheme, in S4, the specific processing of the automatic optical inspection is: automatically scanning the PCB mainboard, collecting images, comparing the tested solder joints with qualified parameters in the database, and checking whether the PCB mainboard has defects after image processing.

[0019] Compared with the prior art, the present invention determines the process direction of the large-size core board through the core board tray, and uses the perforated steel mesh to tin the semicircular pads of the PCB mainboard, and then determines the absorption and identification direction, thereby realizing the mounting of the large-size core board; at the same time, the present invention uses the perforated steel mesh to ensure the amount of printed tin on the PCB mainboard; the present invention is simple to operate and is worthy of vigorous promotion and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of a process for mounting a large-size core board provided by an embodiment of the present invention;

[0021] Figure 2 A schematic structural diagram of a core board tray in a method for mounting a large-size core board provided by an embodiment of the present invention;

[0022] Figure 3 A schematic diagram of a large-size core board in a mounting method of a large-size core board provided by an embodiment of the present invention;

[0023] Figure 4 An enlarged schematic diagram of a solder pad in a method for mounting a large-size core board provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] In the description of the present invention, it should be clarified that the terms "vertical", "lateral", "longitudinal", "front", "rear", "left", "right", "up", "down", "horizontal" and the like indicating orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not mean that the device or element referred to must have a specific orientation or position, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] Example

[0027] A mounting method for a large-size core board provided by an embodiment of the present invention is shown in Figure 1 , including the following steps:

[0028] S1, placing a large-size core board on a core board tray, and determining a process direction of the core board tray;

[0029] S2, using a perforated steel mesh to tin the semicircular pads on the PCB main board;

[0030] S3, determine the absorption and recognition direction, and segment the image according to the appearance characteristics of the large-size core board, and then locate and identify the large-size core board and mount it;

[0031] S4, reflow soldering and automatic optical inspection of large-size core boards and PCB motherboards.

[0032] After adopting the above scheme, the present invention determines the process direction of the large-size core board through the core board tray, and uses the perforated steel mesh to tin the semicircular pads of the PCB mainboard, and then determines the absorption and identification direction, thereby realizing the mounting of the large-size core board; at the same time, the present invention uses the perforated steel mesh to ensure the amount of printed tin on the PCB mainboard; the present invention is simple to operate and is worthy of vigorous promotion and use.

[0033] See also Figure 1 and Figure 2In the specific implementation process of the embodiment of the present invention, further, the short side direction of the large-size core board in S1 is the X-axis, and the process direction of the core board tray is the X-axis direction. In the present invention, the direction of the large-size core board production process is defined as the X-axis direction, and the short side of the large-size core board is set in the X-axis direction. This setting solves the limitation that the patch equipment cannot rotate and mount the large-size core board.

[0034] Furthermore, the core board tray in the embodiment of the present invention adopts a 10-slot tray.

[0035] Furthermore, in the embodiment of the present invention, an SM482 device is used as a patch device.

[0036] In the specific implementation process of the embodiment of the present invention, further, the size of the core board tray in S1 in the X-axis direction is less than 70 mm. The size of the core board tray in the X-axis direction is less than 70 mm, which will limit the size of the large-sized core board in the X-axis direction to less than 70 mm, so that the SM482 device can mount the large-sized core board.

[0037] In the specific implementation process of the embodiment of the present invention, further, in S2, the specific method of tinning is: applying solder paste on the surface of the perforated steel mesh, and transferring the solder paste to the pad of the PCB main board. The present invention uses the perforated steel mesh to tinn to ensure that the pad of the PCB main board can obtain sufficient tin.

[0038] See also Figure 3 and Figure 4 In the specific implementation process of the embodiment of the present invention, further, the volume of tin in the perforated steel mesh in S2> the volume requirement of tin in the semicircular pad of the PCB mainboard × 70%. The volume of tin on the perforated steel mesh in S2 of the present invention must meet the above requirements, and the total volume requirement of the tin in the pad is calculated by using the volume of solder in the unit area of ​​each pad.

[0039] Furthermore, the volume of tin in the open-cell steel mesh in the embodiment of the present invention is calculated as follows:

[0040]

[0041] See also Figure 4 , where V 钢网 is the volume of tin in the perforated steel mesh, L1, L2, L3 and L4 are the lengths of the sides of the perforated holes, H is the thickness, and the solid content of the solder paste is 90%.

[0042] Furthermore, the volume of the tin amount of the semicircular pad of the PCB main board is the volume of the semicircular hole of the PCB main board.

[0043] See also Figure 1In the specific implementation process of the embodiment of the present invention, further, in S3, the suction and identification direction is the X-axis direction. During the suction and identification process, the patch equipment needs to set the X-axis direction as the suction and identification direction, so as to ensure that the large-sized core board transported by the core board tray can be sucked and identified.

[0044] See also Figure 1 In the specific implementation process of the embodiment of the present invention, further, the symmetrical corners of the large-size core board are captured at least twice during positioning and identification in S3. The patch device identifies the large-size core board at least twice by segmenting the image, and performs contour feature point identification, so that the patch device can accurately patch.

[0045] Furthermore, the suction recognition angle is set to 0°, and the patch angle is also set to 0°. This setting can circumvent the limitations of the patch equipment, so that large-size core boards can be accurately patched on the core board tray.

[0046] See also Figure 1 In the specific implementation process of the embodiment of the present invention, further, in S4, the reflow soldering process is specifically a reflow soldering furnace. Reflow soldering is a process of permanently combining a large-sized core board with a PCB mainboard. In the present invention, the reflow soldering furnace provides a heating environment to melt the solder paste in the tin tray by heat, so that the large-sized core board and the semicircular pad on the PCB mainboard are reliably combined together through the solder paste.

[0047] See also Figure 1 In the specific implementation process of the embodiment of the present invention, further, in S4, the specific processing of the automatic optical inspection is: automatically scanning the PCB mainboard, collecting images, comparing the tested solder joints with the qualified parameters in the database, and checking whether the PCB mainboard has defects after image processing. If the PCB mainboard has defects, rework or scrapping is performed, and if the PCB mainboard does not have defects, it passes.

[0048] The workflow of a large-size core board mounting method provided by an embodiment of the present invention is as follows:

[0049] S1, place the large-size core board on the core board pallet, and determine the process direction of the core board pallet: define the short side direction of the large-size core board as the X-axis, the process direction of the core board pallet as the X-axis direction, and the size of the core board pallet in the X-axis direction is less than 70mm.

[0050] S2, use the perforated steel mesh to tin the pads on the PCB main board: apply solder paste on the surface of the perforated steel mesh, and transfer the solder paste to the pads of the PCB main board, and the volume of tin in the perforated steel mesh>the volume requirement of tin on the PCB main board pads*70%.

[0051] S3, determine the suction recognition direction, and segment the image according to the appearance characteristics of the large-size core board, and then locate and identify the large-size core board and paste it: the suction recognition direction is the X-axis direction, the patch equipment identifies the large-size core board by segmenting the image at least twice, and identifies the outline feature points. The suction recognition angle and the patch angle are both set to 0° to complete the patch.

[0052] S4, reflow soldering and automatic optical inspection of large-size core boards and PCB mainboards: provide a heating environment to melt the solder paste in the tin tray, so that the pads on the large-size core board and PCB mainboard can be reliably combined through the solder paste; automatically scan the PCB mainboard, collect images, compare the tested solder joints with the qualified parameters in the database, and check whether the PCB mainboard has defects after image processing. If the PCB mainboard has defects, it will be reworked or scrapped. If the PCB mainboard does not have defects, it will pass.

[0053] To sum up, the present invention determines that the process direction of the large-size core board is the X-axis direction through the core board tray, determines that the maximum size in the X-axis direction is less than 70mm, and uses the perforated steel mesh to tin the semicircular pads of the PCB mainboard, and then determines that the absorption recognition angle and the mounting angle are both 0°, thereby realizing the mounting of the large-size core board; at the same time, the present invention uses the perforated steel mesh to ensure the amount of printed tin on the semicircular pads of the PCB mainboard; the present invention combines the large-size core board with the PCB mainboard for mounting, integrates the high-speed interface and communication module of the core function through the core module, and can develop customized large-size core boards according to customer customization requirements, cooperates with the public PCB mainboard, greatly reduces the product development cycle and the efficiency of product iteration and upgrading, and at the same time, the communication requirements of the peripheral lines of the PCB mainboard can also be met by the bottom number of boards, which greatly saves the material cost of the PCB mainboard.

[0054] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for mounting a large-size core board, characterized in that: The following steps are involved: S1, placing the large-size core board on a core board tray, and determining the process direction of the core board tray; S2, using a perforated steel mesh to tin the semicircular pads on the PCB main board; S3, determining the absorption and identification direction, and segmenting the image according to the appearance characteristics of the large-size core board, and then positioning, identifying and pasting the large-size core board; S4, reflow soldering and automatic optical inspection of large-size core boards and PCB motherboards.

2. A method for mounting a large-size core board according to claim 1, characterized in that: The short side direction of the large-size core board in S1 is the X-axis, and the process direction of the core board tray is the X-axis direction.

3. A method for mounting a large-size core board according to claim 2, characterized in that: The dimension of the core board tray in the X-axis direction is less than 70 mm.

4. The mounting method of a large-size core board according to claim 1, characterized in that: In S2, the specific method of tinning is: applying solder paste on the surface of the perforated steel mesh, and transferring the solder paste to the semicircular pads of the PCB mainboard.

5. A method for mounting a large-size core board according to claim 4, characterized in that: In S2, the volume of tin in the perforated steel mesh>the volume requirement of tin in the semicircular pad of the PCB mainboard×70%.

6. The mounting method of a large-size core board according to claim 2, characterized in that: The absorption and identification direction in S3 is the X-axis direction.

7. A method for mounting a large-size core board according to claim 6, characterized in that: During the positioning and identification in S3, the symmetrical corners of the large-size core board are captured at least twice.

8. A method for mounting a large-size core board according to claim 7, characterized in that: The absorption recognition angle is set to 0°, and the patch angle is also set to 0°.

9. A method for mounting a large-size core board according to any one of claims 1 to 9, characterized in that: In S4, the specific process of the reflow soldering is: the solder paste in the tin tray is heated and melted by a reflow soldering furnace, thereby combining the large-size core board and the semicircular solder pad on the PCB main board.

10. A method for mounting a large-size core board according to any one of claims 1 to 9, characterized in that: In S4, the specific processing of the automatic optical inspection is: automatically scanning the PCB mainboard, collecting images, comparing the tested solder joints with qualified parameters in the database, and checking whether the PCB mainboard has defects after image processing.

Images