Auxiliary device for vertical tin spraying of circuit board
The auxiliary device with a limiting guide assembly addresses the issue of inconsistent wind knife pressure by using a frame cover and guide wheels to maintain uniformity of the tin layer thickness on PCB boards during hot air solder leveling.
Patent Information
- Application Number
- CN202420615108.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-28
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2034-03-28
AI Technical Summary
In existing PCB manufacturing processes, the inconsistency in wind knife pressure on the front and rear sides of PCB boards during hot air solder leveling leads to deformation, scratching, and uneven tin layer thickness, resulting in product quality defects.
An auxiliary device with a limiting guide assembly, comprising a frame cover, front and rear air knives, and side and back limiting guide wheels, ensures consistent air pressure and guides the PCB board to prevent deformation and scratching, ensuring uniform tin layer thickness.
The device prevents PCB board deformation and scratching, ensuring consistent tin layer thickness and improving product quality by guiding the board during hot air leveling.
Smart Images
Figure CN222263157U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of PCB manufacturing, in particular to an auxiliary device for vertical tin spraying on a circuit board. Background Art
[0002] Hot air solder leveling, also known as hot air leveling, is a step and process in the production process of PCB boards. Hot air solder leveling is to coat a layer of tin-lead alloy on the copper surface to prevent the copper surface from oxidizing and provide a good soldering foundation for subsequent assembly processes. Specifically, the PCB board is immersed in a molten solder pool so that all exposed copper surfaces are covered with solder. Then, the excess solder on the PCB board is removed by a hot air cutter. Because the surface of the circuit board after tin spraying is the same material as the solder paste, the welding strength and reliability are better.
[0003] In existing production, PCB boards are vertically immersed in or moved out of the tin furnace through a lifting assembly, and hot air leveling is performed by setting front and rear air knives on the front and rear sides of the moving path of the PCB board above the tin furnace. In production, it is difficult to keep the wind knife pressure on the front and rear sides of the PCB board consistent, and there is a pressure difference. The PCB board that is softened by heat will be deformed and shifted forward and backward under the action of the wind knife pressure difference, which will not only make the thickness of the tin layer uneven, but also make the PCB board easily scratched during the lifting process, resulting in product quality defects. Utility Model Content
[0004] In order to overcome the problems existing in the related technology, the utility model provides an auxiliary device for vertical tin spraying of circuit boards. By setting a limiting guide component, the PCB board is limited and guided during the hot air leveling process to avoid scratches and excessive deformation of the PCB board, thereby ensuring the uniformity of the tin layer thickness.
[0005] The purpose of this utility model is to provide an auxiliary device for vertical tin spraying on circuit boards:
[0006] It includes a frame cover, a front air knife, a rear air knife and a limit guide assembly;
[0007] The frame cover is arranged on the top of the tin melting tank, and one side of the frame cover is hinged to the tin melting tank;
[0008] The front air knife and the rear air knife are installed in the frame cover at a front-to-back interval, and a section for the PCB board to pass vertically is formed between the front air knife and the rear air knife. The air outlets of the front air knife and the rear air knife are both oriented toward the section. The air inlets of the front air knife and the rear air knife are both provided with a pressure regulating valve, and the air outlet pressure of the front air knife is not less than that of the rear air knife.
[0009] The limiting guide assembly is installed in the frame cover and is located below the rear wind knife. The limiting guide assembly includes a side limiting guide wheel and a back limiting guide wheel. Both the side limiting guide wheel and the back limiting guide wheel are located in the interval. The side limiting guide wheel is perpendicular to the axis of the back limiting guide wheel. Two side limiting guide wheels are provided, and the two side limiting guide wheels are respectively used to fit the left and right sides of the PCB board. At least one back limiting guide wheel is provided, and the back limiting guide wheel is located between the two side limiting guide wheels. The back limiting guide wheel is used to fit the side of the PCB board facing the rear wind knife.
[0010] In a preferred technical solution of the utility model, a cross beam is installed in the frame cover below the rear wind knife, and the side limit guide wheels and the back limit guide wheels both slide with the cross beam in the transverse direction, and the side limit guide wheels and the back limit guide wheels are locked with the cross beam by locking members.
[0011] In a preferred technical solution of the utility model, a slide rail is installed on the crossbeam, each side limit guide wheel and each back limit guide wheel are respectively installed on different sliders through wheel frames, each slider is installed on the slide rail, and the locking piece is arranged on the slider.
[0012] In a preferred technical solution of the utility model, the wheel frame has a base, and a longitudinal bar hole perpendicular to the crossbeam is opened on the base, and a screw for locking the wheel frame and the slider penetrates through the longitudinal bar hole.
[0013] In a preferred technical solution of the present utility model, the locking member is a locking nail.
[0014] In a preferred technical solution of the utility model, a handle is provided on the front side of the frame cover, and the bottom end of the rear side of the frame cover is hinged to the molten tin tank.
[0015] In a preferred technical solution of the present utility model, the side limiting guide wheel and the back limiting guide wheel are made of ceramic or polytetrafluoroethylene.
[0016] In a preferred technical solution of the present utility model, the top surface and the bottom surface of the frame cover are not closed.
[0017] The beneficial effects of the utility model are:
[0018] The frame cover is arranged on the top of the tin melting tank, and one side of the frame cover is hinged to the tin melting tank to open and close the tin melting tank; the front air knife and the rear air knife are installed on the frame cover at intervals in front and behind, and the air inlets of the front air knife and the rear air knife are provided with pressure regulating valves, and the pressure regulating valves are used to make the air outlet pressure of the front air knife not less than that of the rear air knife, so that when the air knife performs hot air leveling, the PCB board can only swing backwards, and a side limit guide wheel and a back limit guide wheel are arranged under the rear air knife. Two side limit guide wheels are arranged, and the two side limit guide wheels can respectively fit the left and right sides of the PCB board to limit and guide the PCB board, and when the PCB board swings backwards, the back limit guide wheel can fit the PCB board to limit and guide the PCB board, prevent the PCB board from swinging, avoid scratches and excessive deformation of the PCB board, and thus ensure the uniformity of the tin layer thickness. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 It is a schematic diagram of the structure of an auxiliary device used for vertical tin spraying on circuit boards.
[0020] Figure 2 It is a structural cross-sectional view of an auxiliary device used for vertical tin spraying on circuit boards.
[0021] Figure 3 It is a schematic diagram of the structure on the air inlet side.
[0022] Reference numerals:
[0023] 100, frame cover; 110, handle; 200, front air knife; 300, rear air knife; 400, PCB board; 500, fixture; 600, limit guide assembly; 610, crossbeam; 620, slider; 630, wheel frame; 631, base; 632, longitudinal strip hole; 640, back limit guide wheel; 650, side limit guide wheel; 660, bolt; 670, nut; 680, end bearing. DETAILED DESCRIPTION
[0024] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.
[0025] Hot air solder leveling, also known as hot air leveling, is a step and process in the production process of PCB boards. Hot air solder leveling is to coat a layer of tin-lead alloy on the copper surface to prevent the copper surface from oxidizing and provide a good soldering foundation for subsequent assembly processes. Specifically, the PCB board is immersed in a molten solder pool or molten tin tank so that all exposed copper surfaces are covered with solder. Then, the excess solder on the PCB board is removed by a hot air cutter. Because the surface of the circuit board after tin spraying is the same material as the solder paste, the welding strength and reliability are better.
[0026] In existing production, PCB boards are vertically immersed in or moved out of the tin furnace through a lifting assembly, and hot air leveling is performed by setting front and rear air knives on the front and rear sides of the moving path of the PCB board above the tin furnace. In production, it is difficult to keep the wind knife pressure on the front and rear sides of the PCB board consistent, and there is a pressure difference. The PCB board that is softened by heat will be deformed and shifted forward and backward under the action of the wind knife pressure difference, which will not only make the thickness of the tin layer uneven, but also make the PCB board easily scratched during the lifting process, resulting in product quality defects.
[0027] Example
[0028] In response to the above problems, this embodiment provides an auxiliary device for vertical tin spraying on a circuit board. A limiting guide assembly 600 is provided to limit and guide the PCB board 400 during the hot air leveling process, thereby preventing the PCB board 400 from being scratched and excessively deformed, thereby ensuring the uniformity of the tin layer thickness.
[0029] like Figure 1-3 As shown, an auxiliary device for vertical tin spraying on circuit boards:
[0030] It includes a frame cover 100, a front air knife 200, a rear air knife 300 and a limit guide assembly 600;
[0031] The frame cover 100 is arranged on the top of the tin melting tank. The tin melting tank contains liquid tin-lead alloy for the PCB board 400 to immerse in to realize tin spraying. One side of the frame cover 100 is hinged to the tin melting tank. When maintenance or addition of tin-lead alloy is required, the tin melting tank can be opened through the frame cover 100.
[0032] The front wind knife 200 and the rear wind knife 300 are installed in the frame cover 100 at intervals in front and back, and a section for the PCB board 400 to pass vertically is formed between the front wind knife 200 and the rear wind knife 300. The air outlets of the front wind knife 200 and the rear wind knife 300 are both oriented toward the section. Preferably, the air outlets of the front wind knife 200 and the rear wind knife 300 are arranged relatively to each other, and heaters are arranged in the front wind knife 200 and the rear wind knife 300. The air inlets of the front wind knife 200 and the rear wind knife 300 are both provided with pressure regulating valves, and the pressure regulating valves are connected to a high-pressure air source through a hose. The pressure regulating valves make the air outlet pressure of the front wind knife 200 not less than that of the rear wind knife 300, so that when the wind knife performs hot air leveling, the PCB board 400 can only swing backwards;
[0033] The limiting guide assembly 600 is installed in the frame cover 100 and is located below the rear wind knife 300 to limit the PCB board 400 from swinging backward; the limiting guide assembly 600 includes a side limiting guide wheel 650 and a back limiting guide wheel 640, both of which are located in the interval, and the side limiting guide wheel 650 is perpendicular to the axis of the back limiting guide wheel 640, and two side limiting guide wheels 650 are provided, and the two side limiting guide wheels 650 are respectively used to fit the left and right sides of the PCB board 400 to perform lateral limiting and vertical guiding on the PCB board 400, and at least one back limiting guide wheel 640 is provided, and the back limiting guide wheel 640 is located on the two side limiting guide wheels. The back limiting guide wheel 640 is tangent to the back of the PCB board 400 in a vertical state, or the spacing between the back limiting guide wheel 640 and the back of the PCB board 400 in a vertical state is not greater than 2 mm. When the PCB board 400 has a tendency to swing backward due to the pressure difference between the front and rear wind knives 300, after the PCB board 400 contacts the back limiting guide wheel 640, the swinging force will be offset by the back limiting guide wheel 640. The back limiting guide wheel 640 can fit the PCB board 400 to longitudinally limit and vertically guide the PCB board 400, prevent the PCB board 400 from swinging, avoid scratches and excessive deformation of the PCB board 400, and thus ensure the uniformity of the tin layer thickness.
[0034] In this embodiment, in order to enable the side limit guide wheel 650 and the back limit guide wheel 640 to be flexibly adjusted according to the width size of the PCB board 400, a cross beam 610 is installed in the frame cover 100 below the rear wind knife 300, and the side limit guide wheel 650 and the back limit guide wheel 640 are both slidably matched with the cross beam 610 in the horizontal direction, and the side limit guide wheel 650 and the back limit guide wheel 640 are both locked with the cross beam 610 by locking members.
[0035] In this embodiment, a slide rail is installed on the crossbeam 610, and each side limit guide wheel 650 and each back limit guide wheel 640 are respectively installed on different sliders 620 through the wheel frame 630, each slider 620 is installed on the slide rail, and the locking member is arranged on the slider 620. Specifically, in order to ensure that the side limit guide wheel 650 and the back limit guide wheel 640 can roll smoothly, the side limit guide wheel 650 and the back limit guide wheel 640 are installed at the end of the wheel frame 630 through bolts 660 and nuts 670, and end bearings 680 are arranged between the guide wheel and the nut 670 and between the guide wheel and the wheel frame 630. The guide wheel and the end bearing 680 sets are arranged on the screw rod, and the guide wheel is the side limit guide wheel 650 or the back limit guide wheel 640.
[0036] In this embodiment, in order to realize that the side limiting guide wheel 650 and the back limiting guide wheel 640 can be flexibly adjusted according to the thickness of the PCB board 400, the wheel frame 630 has a base 631, and the base 631 is provided with a longitudinal bar hole 632 perpendicular to the beam 610, and the longitudinal bar hole 632 is penetrated by a screw for locking the wheel frame 630 and the slider 620.
[0037] In this embodiment, the locking member is a locking nail.
[0038] Specific:
[0039] Before tin spraying, the positions of the side limiting guide wheel 650 and the back limiting guide wheel 640 are adjusted accordingly according to the size parameters of the PCB board 400;
[0040] During tin spraying, the PCB board 400 is connected to the lifting assembly through the clamp 500, and the lifting assembly drives the PCB board 400 to move downward through the interval and immerse in the molten tin tank for tin spraying;
[0041] After the tin spraying is completed, the lifting assembly drives the PCB board 400 to move upward, and at the same time, the front air knife 200 and the rear air knife 300 blow out high-pressure hot air to perform hot air leveling on the front and rear sides of the PCB board 400 passing through the interval to remove excess tin on the PCB board 400. Because the air outlet pressure of the front air knife 200 is not less than that of the rear air knife 300 through the pressure regulating valve, the PCB board 400 can only swing backward when the air knife performs hot air leveling. During this process, the back limit guide wheel 640 can fit the PCB board 400 to limit and guide the PCB board 400, prevent the PCB board 400 from swinging, avoid scratches and excessive deformation of the PCB board 400, and thus ensure the uniformity of the tin layer thickness.
[0042] In this embodiment, a handle 110 is provided on the front side of the frame cover 100, and the bottom end of the rear side of the frame cover 100 is hinged to the molten tin bath.
[0043] In this embodiment, in order to make the side limiting guide wheel 650 and the back limiting guide wheel 640 resistant to high temperature, the side limiting guide wheel 650 and the back limiting guide wheel 640 are made of ceramic or polytetrafluoroethylene.
[0044] In this embodiment, the top and bottom surfaces of the frame cover 100 are not sealed to facilitate the passage of the PCB board 400 .
[0045] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values of the parts and steps set forth in these embodiments do not limit the scope of the application. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a restriction. Therefore, other examples of exemplary embodiments can have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in the subsequent accompanying drawings.
[0046] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.
[0047] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.
[0048] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.
[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. An auxiliary device for vertical tin spraying on a circuit board, characterized in that: It includes a frame cover, a front air knife, a rear air knife and a limit guide assembly; The frame cover is arranged on the top of the tin melting tank, and one side of the frame cover is hinged to the tin melting tank; The front air knife and the rear air knife are installed in the frame cover at a front-to-back interval, and a section for the PCB board to pass vertically is formed between the front air knife and the rear air knife. The air outlets of the front air knife and the rear air knife are both oriented toward the section. The air inlets of the front air knife and the rear air knife are both provided with a pressure regulating valve, and the air outlet pressure of the front air knife is not less than that of the rear air knife. The limiting guide assembly is installed in the frame cover and is located below the rear wind knife. The limiting guide assembly includes a side limiting guide wheel and a back limiting guide wheel. Both the side limiting guide wheel and the back limiting guide wheel are located in the interval. The side limiting guide wheel is perpendicular to the axis of the back limiting guide wheel. Two side limiting guide wheels are provided, and the two side limiting guide wheels are respectively used to fit the left and right sides of the PCB board. At least one back limiting guide wheel is provided, and the back limiting guide wheel is located between the two side limiting guide wheels. The back limiting guide wheel is used to fit the side of the PCB board facing the rear wind knife.
2. The auxiliary device for vertical tin spraying of circuit boards according to claim 1, characterized in that: A crossbeam is installed in the frame cover below the rear wind knife, and the side limit guide wheel and the back limit guide wheel are both slidably matched with the crossbeam in the transverse direction, and the side limit guide wheel and the back limit guide wheel are locked with the crossbeam through locking pieces.
3. The auxiliary device for vertical tin spraying of circuit boards according to claim 2, characterized in that: A slide rail is installed on the crossbeam, and each side limit guide wheel and each back limit guide wheel are respectively installed on different sliders through wheel frames, each slider is installed on the slide rail, and the locking member is arranged on the slider.
4. The auxiliary device for vertical tin spraying of circuit boards according to claim 3, characterized in that: The wheel frame has a base, and a longitudinal strip hole perpendicular to the cross beam is opened on the base. Screws for locking the wheel frame and the sliding block penetrate through the longitudinal strip hole.
5. The auxiliary device for vertical tin spraying of circuit boards according to claim 3, characterized in that: The locking piece is a locking nail.
6. The auxiliary device for vertical tin spraying of circuit boards according to claim 1, characterized in that: A handle is arranged on the front side of the frame cover, and the bottom end of the rear side of the frame cover is hinged to the molten tin tank.
7. The auxiliary device for vertical tin spraying of circuit boards according to claim 1, characterized in that: The side limiting guide wheel and the back limiting guide wheel are made of ceramic or polytetrafluoroethylene.
8. The auxiliary device for vertical tin spraying of circuit boards according to claim 1, characterized in that: The top surface and the bottom surface of the frame cover are not closed.