A leaded FMC connector assembly method

Abstract

The present invention relates to the technical field of FMC connector assembly, and specifically discloses a leaded FMC connector assembly method, which specifically includes the following steps: preparation; using a solder paste printer to apply solder paste on a printed circuit board pad, and inspecting the quality of the solder paste coating; if the inspection is qualified, using vapor phase reflow soldering to complete pre-tinning of the printed circuit board pad; cleaning the pre-tinned printed circuit board pad; using a solder paste printer to apply solder paste on the pre-tinned pad, and inspecting the quality of the solder paste coating; if the inspection is qualified, mounting the FMC connector, installing a metal counterweight tooling, and using vapor phase reflow soldering to weld the FMC connector; inspecting the welding quality, and completing the assembly. The present invention reduces the temperature of the FMC connector pin, ensures the temperature balance between the printed circuit board pad and the pin; increases the surface tension of the solder on the printed circuit board pad, restrains the solder from flowing to the contact, solves the problem of device wicking open circuit, and improves the one-time welding pass rate of the leaded FMC connector.

Description

Technical Field

[0001] The present invention relates to the technical field of FMC connector assembly, and more particularly to a leaded FMC connector assembly method. Background Art

[0002] The domestic leaded FMC connector consists of an insulating shell, a jack contact and a solder block. The domestic leaded solder block is Sn63Pb37 solder, with a size of 0.97mm×0.57mm×0.3mm, a volume of about 0.146mm, a pin pitch of 1.27mm×1.27mm, and can arrange 186 pairs of differentials. The connector is designed with positioning pins at both ends of the insulating shell, which cooperate with the mounting holes of the printed circuit board to achieve the positioning function. The FMC series connector includes plugs and sockets. Its termination form is similar to that of BGA devices. The solder block is implanted at the reed end by mechanical deformation and riveting. The solder blocks are arranged back to back on the side of the connector pins. However, the FMC connector is different from the BGA device. The ball soldering cannot be performed during rework. Once a soldering problem occurs, the device can only be replaced. It is assembled according to the surface mounting technology of the BGA type device. The solder is Sn63Pb37, the steel mesh thickness is 0.12mm, and the lead-free device on the PCBA has a peak welding temperature of 226℃. When assembling the FMC connector according to this process method, a wicking open circuit welding problem occurred, resulting in a one-time welding pass rate of the connector of only 77.91%. The wicking problem seriously affected product quality and production costs. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a leaded FMC connector assembly method, which effectively solves the problem of device wicking open circuit caused by the existing assembly method.

[0004] The solution adopted by the present invention to solve the technical problem is:

[0005] A leaded FMC connector assembly method specifically includes the following steps:

[0006] Step S1: preparation;

[0007] Step S2: applying solder paste on the printed circuit board pad using a solder paste printer, and inspecting the solder paste coating quality;

[0008] Step S3: If the test is qualified, vapor phase reflow soldering is used to complete the pre-tinning of the printed circuit board pads;

[0009] Step S4: cleaning the pre-tinned printed circuit board pads;

[0010] Step S5: using a solder paste printer to apply solder paste to the pre-tinned printed circuit board pads, and inspecting the solder paste coating quality;

[0011] Step S6: If the inspection is qualified, mount the FMC connector, install the metal counterweight tooling, and weld the FMC connector using vapor phase reflow soldering;

[0012] Step S7: Check welding quality and complete assembly.

[0013] The present invention increases the amount of solder paste, the pre-tinning process of the PCB pad and the metal counterweight tooling; firstly, the solder paste is printed on the pad of the printed circuit board, and then cleaned after reflow soldering; then the amount of printed solder paste is increased by increasing the thickness of the steel mesh, and the components are manually mounted to ensure that the positioning pins of the components are installed in place; then, the metal counterweight tooling is installed on the upper surface of the FMC connector, and the printed circuit board is placed in a vacuum gas phase reflow soldering device to complete the welding.

[0014] The present invention combines the solder paste quantity control technology with the installation and use of metal counterweight tooling technology and the PCB pad pre-tinning process technology to reduce the connector contact temperature and ensure the temperature balance between the PCB pad and the contact; increase the solder surface tension on the PCB pad, restrain the solder from flowing to the contact, solve the device core suction open circuit problem, and improve the one-time welding pass rate of domestic leaded FMC connectors.

[0015] In some possible implementations,

[0016] The solder paste coating in step S2 specifically refers to:

[0017] A fully automatic screen printer and steel mesh are used to print solder paste on the pads of the printed circuit board. The screen printing parameters are: scraper speed 25-35mm / s, scraper pressure 5-7KG, demoulding speed 0.5-0.8mm / s, steel mesh thickness 0.1-0.13mm, and the opening is executed according to the pad size 1:1.

[0018] In some possible implementations,

[0019] The solder paste coating quality inspection in step S2 specifically refers to:

[0020] Use a 20-40x microscope to inspect the quality of solder paste coating to ensure that the solder paste covers 100% of the area of ​​the printed circuit board pads;

[0021] When the test is qualified, execute step S3;

[0022] When the inspection fails, return to step S1.

[0023] In some possible implementations,

[0024] The step S3 specifically refers to reflow soldering using a vacuum vapor phase reflow soldering device; wherein the soldering peak temperature is 210° C.-215° C., and pre-tinning of the printed circuit board pad is completed;

[0025] In some possible implementations,

[0026] The step S5 specifically refers to: using a fully automatic screen printer and a steel mesh to print solder paste on the pad of the printed circuit board, wherein the screen printing parameters are: scraper speed 25-35mm / s, scraper pressure 5-7KG, demolding speed 0.5-0.8mm / s, steel mesh thickness 0.15-0.18mm, and the opening is performed according to the pad size 1:1.

[0027] In some possible implementations,

[0028] The step S6 comprises the following steps:

[0029] Step S61: manually mounting the FMC connector and installing it in place through the positioning pins provided on the FMC connector and the mounting holes on the printed circuit board;

[0030] Step S62: installing a metal counterweight tool on the upper surface of the FMC connector;

[0031] Step S63: using vacuum vapor phase reflow soldering equipment to solder the pins of the FMC connector to the printed circuit board pads;

[0032] In some possible implementations,

[0033] A U-shaped groove for installing the FMC connector is provided at the bottom of the metal counterweight fixture; the length of the metal counterweight fixture is equal to the length of the FMC connector in the long direction.

[0034] In some possible implementations,

[0035] The step S7 specifically refers to using a 20-40 times microscope or X-ray to inspect the welding quality of the FMC connector.

[0036] In some possible implementations,

[0037] The step S1 comprises the following steps:

[0038] Printed circuit board baking;

[0039] FMC connector detection;

[0040] Printed circuit board pad cleaning.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The present invention combines the solder paste quantity control technology with the installation and use of metal counterweight tooling technology and the PCB pad pre-tinning process technology to ensure that the FMC connector is assembled successfully at one time, and the solder joint quality meets the aerospace standard requirements. According to statistics over a period of 6 months, 864 connectors were produced and assembled, and no connector solder joint wicking was open, and the first-time welding pass rate was increased to 99.4%;

[0043] When the FMC connector is welded, the present invention installs a metal counterweight tooling on its upper surface, which can reduce the temperature of the connector contact, thereby reducing the temperature difference between the contact and the PCB pad, weakening the tendency of liquid solder to flow to the contact, and improving wicking;

[0044] The metal counterweight fixture of the present invention provides vertical gravity to the FMC connector during the welding and melting process, thereby increasing the fit between the pin and the printed circuit board pad, and ensuring that the molten tin block is in full contact with the solder paste on the pad to form a qualified solder joint.

[0045] The present invention increases the surface tension of the liquid solder on the pad by designing the pad pre-tinning process parameters and the amount of solder paste in detail, restrains the solder from flowing to the contact piece, ensures that the molten solder block and the solder paste are fully in contact and fused on the pad to form a qualified solder joint, and avoids wicking open circuit.

[0046] The invention is suitable for assembling domestic leaded FMC connectors. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a work flow chart of the present invention;

[0048] Figure 2 It is a schematic diagram of the assembly of the present invention;

[0049] Among them: 1. Metal counterweight tooling; 2. FMC connector; 3. Locating pin; 4. Solder paste; 5. Printed circuit board pad. DETAILED DESCRIPTION

[0050] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. The "first", "second" and similar words mentioned in this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, "one" or "one" and other similar words do not indicate a quantity restriction, but indicate the existence of at least one. In the implementation of this application, "and / or" describes the association relationship of the associated objects, indicating that there can be three relationships, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In the description of the embodiments of the present application, unless otherwise specified, the meaning of "multiple" refers to two or more. For example, multiple positioning columns refer to two or more positioning columns. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] The present invention is described in detail below.

[0052] like Figure 1-Figure 2 As shown,

[0053] A leaded FMC connector assembly method specifically includes the following steps:

[0054] Step S1: preparation; comprising the following steps:

[0055] Printed circuit board baking;

[0056] FMC connector detection;

[0057] Printed circuit board pad cleaning.

[0058] Step S2: applying solder paste on the printed circuit board pad using a solder paste printer, and inspecting the solder paste coating quality;

[0059] When the test is qualified, execute step S3;

[0060] When the inspection fails, return to step S1.

[0061] The solder paste coating in step S2 specifically refers to:

[0062] A fully automatic screen printer and steel mesh are used to print solder paste on the pads of the printed circuit board. The screen printing parameters are: scraper speed 25-35mm / s, scraper pressure 5-7KG, demoulding speed 0.5-0.8mm / s, steel mesh thickness 0.1-0.13mm, and the opening is executed according to the pad size 1:1.

[0063] The solder paste coating quality inspection in step S2 specifically refers to:

[0064] Use a 20-40x microscope to inspect the quality of solder paste coating to ensure that the solder paste covers 100% of the area of ​​the printed circuit board pads;

[0065] Step S3: If the inspection is qualified, vapor phase reflow soldering is used to complete the pre-tinning of the printed circuit board pads; the step S3 specifically refers to reflow soldering using a vacuum vapor phase reflow soldering equipment; wherein the welding peak temperature is 210°C-215°C, and the pre-tinning of the printed circuit board pads is completed;

[0066] Step S4: cleaning the pre-tinned printed circuit board pads;

[0067] Step S5: Use a solder paste printer to apply solder paste on the pre-tinned printed circuit board pads, and inspect the quality of the solder paste coating; if the inspection fails, return to step S4:

[0068] The solder paste coating in step S5 specifically refers to: using a fully automatic screen printer and a steel mesh to print solder paste on the pad of the printed circuit board, wherein the screen printing parameters are: scraper speed 25-35mm / s, scraper pressure 5-7KG, demoulding speed 0.5-0.8mm / s, steel mesh thickness 0.15-0.18mm, and the opening is performed according to the pad size 1:1.

[0069] Step S6: If the inspection is qualified, mount the FMC connector, install the metal counterweight tooling, and weld the FMC connector using vapor phase reflow soldering;

[0070] The step S6 comprises the following steps:

[0071] Step S61: manually mounting the FMC connector and installing it in place through the positioning pins provided on the FMC connector and the mounting holes on the printed circuit board;

[0072] Step S62: installing a metal counterweight tool on the upper surface of the FMC connector;

[0073] Step S63: using vacuum vapor phase reflow soldering equipment to solder the pins of the FMC connector to the printed circuit board pads;

[0074] A U-shaped groove for installing the FMC connector is provided at the bottom of the metal counterweight fixture; the length of the metal counterweight fixture is equal to the length of the FMC connector in the long direction.

[0075] Step S7: Check welding quality and complete assembly.

[0076] The step S7 specifically refers to using a 20-40 times microscope or X-ray to inspect the welding quality of the FMC connector.

[0077] Embodiment 1:

[0078] A leaded FMC connector assembly method specifically includes the following steps:

[0079] Step S1: preparation; comprising the following steps:

[0080] Printed circuit board baking;

[0081] FMC connector detection;

[0082] Printed circuit board pad cleaning.

[0083] Step S2: applying solder paste on the printed circuit board pad using a solder paste printer, and inspecting the solder paste coating quality;

[0084] When the test is qualified, execute step S3;

[0085] When the inspection fails, return to step S1.

[0086] The solder paste coating in step S2 specifically refers to:

[0087] A fully automatic screen printer and steel mesh are used to print solder paste on the pads of the printed circuit board. The screen printing parameters are: scraper speed 25mm / s, scraper pressure 6KG, demoulding speed 0.8mm / s, steel mesh thickness 0.12mm, and the opening is executed according to the pad size 1:1.

[0088] The solder paste coating quality inspection in step S2 specifically refers to:

[0089] Use a 20-40x microscope to inspect the quality of solder paste coating to ensure that the solder paste covers 100% of the area of ​​the printed circuit board pads;

[0090] Step S3: If the inspection is qualified, the printed circuit board pad is pre-tinned by vapor phase reflow soldering; the step S3 specifically refers to reflow soldering by vacuum vapor phase reflow soldering equipment; wherein the welding peak temperature is 210°C-215°C, and the printed circuit board pad is pre-tinned;

[0091] Step S4: cleaning the pre-tinned printed circuit board pads;

[0092] Step S5: Use a solder paste printer to apply solder paste on the pre-tinned printed circuit board pads, and inspect the quality of the solder paste coating; if the inspection fails, return to step S4:

[0093] The solder paste coating in step S5 specifically refers to: using a fully automatic screen printer and a steel mesh to print solder paste on the pad of the printed circuit board, wherein the screen printing parameters are: scraper speed 25mm / s, scraper pressure 6KG, demoulding speed 0.8mm / s, steel mesh thickness 0.18mm, and the opening is performed according to the pad size 1:1.

[0094] Step S6: If the inspection is qualified, mount the FMC connector, install the metal counterweight tooling, and weld the FMC connector using vapor phase reflow soldering;

[0095] The step S6 comprises the following steps:

[0096] Step S61: manually mounting the FMC connector and installing it in place through the positioning pins provided on the FMC connector and the mounting holes on the printed circuit board;

[0097] Step S62: installing a metal counterweight tool on the upper surface of the FMC connector;

[0098] Step S63: using vacuum vapor phase reflow soldering equipment to solder the pins of the FMC connector to the printed circuit board pads;

[0099] A U-shaped groove for installing the FMC connector is provided at the bottom of the metal counterweight fixture; the length of the metal counterweight fixture is equal to the length of the FMC connector in the long direction.

[0100] Step S7: Check welding quality and complete assembly.

[0101] The step S7 specifically refers to using a 20-40 times microscope or X-ray to inspect the welding quality of the FMC connector.

[0102] According to statistics for a period of 6 months, 864 connectors were assembled by adopting the present invention, and none of the connector solder joints had open circuits, and the first-time welding qualified rate was increased to 99.4%. The present invention effectively solves the problem of open circuits in FMC connectors and effectively improves the qualified rate of products.

[0103] The present invention is not limited to the above-mentioned specific embodiments.

[0104] It should be pointed out that, for those skilled in the art, without departing from the principle of the present invention, several modifications and improvements may be made, for example, the outer structure of the metal counterweight tooling may be modified, and the process parameters may be adjusted according to the thickness of the printed circuit board. These changes and modifications shall be deemed to fall within the scope of protection of the present invention.

[0105] The present invention extends to any new features or any new combination disclosed in this specification, and any new method or process steps or any new combination disclosed.

Claims

1. A leaded FMC connector assembly method, characterized in that: The specific steps include: Step S1: preparation; Step S2: applying solder paste on the printed circuit board pad using a solder paste printer, and inspecting the solder paste coating quality; Step S3: If the test is qualified, vapor phase reflow soldering is used to complete the pre-tinning of the printed circuit board pads; Step S4: cleaning the pre-tinned printed circuit board pads; Step S5: using a solder paste printer to apply solder paste to the pre-tinned pads, and inspecting the quality of the solder paste coating; Step S6: If the inspection is qualified, mount the FMC connector, install the metal counterweight tooling, and weld the FMC connector using vapor phase reflow soldering; Step S7: Check welding quality and complete assembly.

2. A leaded FMC connector assembly method according to claim 1, characterized in that: The solder paste coating in step S2 specifically refers to: A fully automatic screen printer and steel mesh are used to print solder paste on the pads of the printed circuit board. The screen printing parameters are: scraper speed 25-35mm / s, scraper pressure 5-7KG, demoulding speed 0.5-0.8mm / s, steel mesh thickness 0.1-0.13mm, and the opening is executed according to the pad size 1:

1.

3. The leaded FMC connector assembly method according to claim 1, characterized in that: The solder paste coating quality inspection in step S2 specifically refers to: Use a 20-40x microscope to inspect the quality of solder paste coating to ensure that the solder paste covers 100% of the area of ​​the printed circuit board pads; When the test is qualified, execute step S3; When the inspection fails, return to step S1.

4. The leaded FMC connector assembly method according to claim 1, characterized in that: The step S3 specifically refers to reflow soldering using a vacuum vapor phase reflow soldering device; wherein the soldering peak temperature is 210° C.-215° C., and pre-tinning of the printed circuit board pads is completed.

5. The leaded FMC connector assembly method according to claim 1, characterized in that: The step S5 specifically refers to: using a fully automatic screen printer and a steel mesh to print solder paste on the pre-tinned pad, wherein the screen printing parameters are: scraper speed 25-35mm / s, scraper pressure 5-7KG, demolding speed 0.5-0.8mm / s, steel mesh thickness 0.15-0.18mm, and the opening is executed according to the pad size 1:

1.

6. The leaded FMC connector assembly method according to claim 1, characterized in that: The step S6 comprises the following steps: Step S61: manually mounting the FMC connector and installing it in place through the positioning pins provided on the FMC connector and the mounting holes on the printed circuit board; Step S62: installing a metal counterweight tool on the upper surface of the FMC connector; Step S63: Use vacuum vapor phase reflow soldering equipment to solder the pins of the FMC connector to the printed circuit board pads.

7. A leaded FMC connector assembly method according to claim 6, characterized in that: A U-shaped groove for installing the FMC connector is provided at the bottom of the metal counterweight fixture; the length of the metal counterweight fixture is equal to the length of the FMC connector in the long direction.

8. A leaded FMC connector assembly method according to any one of claims 1 to 7, characterized in that: The step S7 specifically refers to using a 20-40 times microscope or X-ray to inspect the welding quality of the FMC connector.

9. The leaded FMC connector assembly method according to claim 8, characterized in that: The step S1 comprises the following steps: Printed circuit board baking; FMC connector detection; Printed circuit board pad cleaning.

Images