Double-track nitrogen furnace for reflow soldering of PCB (Printed Circuit Board)

Abstract

The utility model discloses a double-track nitrogen furnace for reflow soldering of a PCB, and relates to the technical field of PCB production. The device comprises a furnace body, a double-track conveying device is arranged on the furnace body, a preheating area, a backflow area and a cooling area which are distributed in sequence are constructed in the furnace body, first partition pieces are arranged at an inlet and an outlet of the backflow area, each first partition piece comprises a door-shaped frame, a winding roller is arranged on each door-shaped frame, and the winding rollers are arranged on the door-shaped frames. A partition curtain is wound around the winding roller, and a bottom rod is arranged at the free end of the partition curtain. When the device is used, through the matching effect of the first partition piece and the second partition piece, nitrogen filled into the backflow area is partitioned, meanwhile, air in the preheating area and the cooling area is partitioned, the possibility that the nitrogen is diffused from the backflow area to the preheating area and the cooling area is reduced, and the cooling efficiency is improved. The possibility that air diffuses from a preheating area and a cooling area to a backflow area is reduced, the nitrogen consumption is reduced, and meanwhile the possibility that soldering paste is oxidized is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of PCB circuit board production, and in particular to a double-track nitrogen furnace for reflow soldering of PCB circuit boards. Background Art

[0002] PCB Chinese name is printed circuit board, also known as printed circuit board, is an important electronic component, the support of electronic components, and the carrier of electrical connection of electronic components. In the production process of PCB circuit board, it needs to go through the reflow process. Solder paste is scraped on the pad of the circuit board, the patch components are pressed on the welding position and fit with the solder paste, and the circuit board is sent to the reflow oven for welding. Reflow has at least three temperature zones, namely preheating zone, reflow zone and cooling zone. When the circuit board passes through the reflow zone, the solder paste melts into liquid, and the patch components are combined with the solder paste. At the same time, nitrogen is filled into the reflow zone to form nitrogen Protective layer, reduce the possibility of solder paste oxidation, when the circuit board passes through the cooling zone, the solder paste solidifies into a solid state, so that the patch component and the circuit board are integrated. The existing nitrogen furnace usually adopts a double-track design, that is, two circuit boards are transported respectively through two tracks to improve work efficiency. In the prior art, the nitrogen filled in the reflow zone will diffuse to the preheating zone and the cooling zone, and the air in the preheating zone and the cooling zone will diffuse to the reflow zone, which not only increases the consumption of nitrogen, but also easily increases the possibility of solder paste oxidation, thereby affecting the welding effect. Therefore, a double-track nitrogen furnace for PCB circuit board reflow soldering is proposed. Utility Model Content

[0003] The purpose of the present application is to solve the technical problem that the nitrogen filled in the reflow zone will diffuse into the preheating zone and the cooling zone, and the air in the preheating zone and the cooling zone will diffuse into the reflow zone, which not only increases the nitrogen consumption, but also easily increases the possibility of oxidation of the solder paste, thereby affecting the welding effect. The present application provides a dual-track nitrogen furnace for PCB circuit board reflow soldering.

[0004] In order to achieve the above-mentioned purpose, this application specifically adopts the following technical solutions:

[0005] A double-track nitrogen furnace for reflow soldering of PCB circuit boards comprises a furnace body, a double-track conveying device is arranged on the furnace body, a preheating zone, a reflow zone and a cooling zone are sequentially distributed in the furnace body, a first partition is arranged at the entrance and the exit of the reflow zone, the first partition comprises a gantry, a winding roller is arranged on the gantry, a partition curtain is wound on the winding roller, a bottom rod is arranged at the free end of the partition curtain, a channel for the circuit board to pass through is formed between the bottom rod and the double-track conveying device, and a second partition acting on the channel is arranged on the gantry and the bottom rod.

[0006] Furthermore, the winding roller is rotatably arranged on a gantry frame, and two screw rods are rotatably arranged inside the gantry frame. A slider is threadedly arranged on the screw rod that slides with the gantry frame and is connected to the bottom rod. The screw rod and the winding roller are connected through a bevel gear assembly.

[0007] Furthermore, two guide rollers are rotatably arranged in the portal frame and are both in rolling overlap with the partition curtain.

[0008] Furthermore, the furnace body is provided with a driving member which acts on the two winding rollers and drives the two to rotate synchronously.

[0009] Furthermore, the driving member includes a driving motor arranged in the cooling zone, the two winding rollers are connected by a pulley assembly, and the output shaft of the driving motor is connected to one of the winding rollers by a gear pair.

[0010] Furthermore, the second partition member includes a fixed pipe arranged on the portal frame, and a conical air duct is arranged on the bottom rod, and the fixed pipe and the air duct are connected through a plurality of hoses.

[0011] Furthermore, the inner diameters of the plurality of hoses decrease successively along the length direction of the fixed pipe.

[0012] Furthermore, a three-way pipe is provided on the furnace body, and two ends of the three-way pipe are respectively connected to the two fixed pipes.

[0013] The beneficial effects of this application are as follows:

[0014] When the present application is in use, the nitrogen filled into the reflow zone is isolated by the cooperation of the first partition member and the second partition member, and the air in the preheating zone and the cooling zone is isolated at the same time, thereby reducing the possibility of nitrogen diffusion from the reflow zone to the preheating zone and the cooling zone, and reducing the possibility of air diffusion from the preheating zone and the cooling zone to the reflow zone. This not only reduces the nitrogen consumption, but also reduces the possibility of solder paste oxidation, thereby ensuring the welding effect, and is therefore more practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a three-dimensional diagram of the structure of this application;

[0016] Figure 2 It is a three-dimensional cross-sectional view of the present application;

[0017] Figure 3 This application Figure 2 The enlarged view of point A in the middle;

[0018] Figure 4 This application Figure 2 The enlarged view of point B in the middle;

[0019] Figure 5 It is a three-dimensional diagram of the structure of part of this application;

[0020] Figure 6 This application Figure 5 A three-dimensional cross-sectional view of

[0021] Figure 7 This application Figure 6 Enlarged view of point C in the middle;

[0022] Figure 8 This application Figure 6 Enlarged view of point D in the middle.

[0023] Figure numerals: 1. furnace body; 2. double-track conveying device; 3. preheating zone; 4. reflux zone; 5. cooling zone; 6. gantry; 7. winding roller; 8. partition curtain; 9. bottom rod; 10. screw rod; 11. slider; 12. bevel gear assembly; 13. guide roller; 14. driving motor; 15. pulley assembly; 16. gear pair; 17. fixed pipe; 18. air duct; 19. hose; 20. three-way pipe. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0025] like Figure 1-Figure 8 As shown, a double-track nitrogen furnace for PCB circuit board reflow soldering proposed in one embodiment of the present application includes a furnace body 1, a double-track conveying device 2 is arranged on the furnace body 1, and the double-track conveying device 2 is used to convey the circuit board in the horizontal direction. The furnace body 1 is structured with a preheating zone 3, a reflow zone 4 and a cooling zone 5 distributed in sequence. The preheating zone 3, the reflow zone 4 and the cooling zone 5 are distributed in sequence according to the conveying direction of the circuit board. A first partition is provided at the entrance and the exit of the reflow zone 4. The first partition can play a role in isolating the nitrogen filled in the reflow zone 4, and at the same time, it plays a role in isolating the air in the preheating zone 3 or the cooling zone 5. The first partition includes a door frame 6, and the door frame 6 is in a vertical direction. 6 is provided with a winding roller 7, the winding roller 7 is in a horizontal direction, a partition curtain 8 is wound on the winding roller 7, a bottom rod 9 is provided at the free end of the partition curtain 8, the bottom rod 9 is in a horizontal direction, and the door-shaped area of ​​the gantry 6 can be shielded by the cooperation of the bottom rod 9 and the partition curtain 8. The nitrogen filled into the reflow area 4 is isolated by the cooperation of the gantry 6, the partition curtain 8 and the bottom rod 9, and the air in the preheating area 3 or the cooling area 5 is isolated. A channel for the circuit board to pass through is formed between the bottom rod 9 and the double-track conveying device 2. The gantry 6 and the bottom rod 9 are provided with a second partition member acting on the channel. The second partition member can isolate the channel without affecting the normal passage of the circuit board.

[0026] When in use, the circuit board is transported horizontally by the double-track conveying device 2, and the circuit board passes through the preheating zone 3, the reflow zone 4 and the cooling zone 5 in sequence. When the circuit board passes through the reflow zone 4, nitrogen is filled into the reflow zone 4, and the nitrogen filled into the reflow zone 4 is blocked by the cooperation of the first partition member and the second partition member, and the air in the preheating zone 3 and the cooling zone 5 is blocked at the same time, so as to reduce the possibility of nitrogen diffusion from the reflow zone 4 to the preheating zone 3 and the cooling zone 5, and reduce the possibility of air diffusion from the preheating zone 3 and the cooling zone 5 to the reflow zone 4, which not only reduces the consumption of nitrogen, but also reduces the possibility of oxidation of the solder paste, thereby ensuring the welding effect;

[0027] To summarize, when the present application is in use, the nitrogen filled into the reflow zone 4 is isolated through the cooperation of the first partition member and the second partition member, and the air in the preheating zone 3 and the cooling zone 5 is isolated at the same time, thereby reducing the possibility of nitrogen diffusion from the reflow zone 4 to the preheating zone 3 and the cooling zone 5, and reducing the possibility of air diffusion from the preheating zone 3 and the cooling zone 5 to the reflow zone 4. This not only reduces the nitrogen consumption, but also reduces the possibility of oxidation of the solder paste, thereby ensuring the welding effect, and is therefore more practical.

[0028] like Figure 7-Figure 8 As shown, in some embodiments, the winding roller 7 is rotatably arranged on the gantry 6, and two screw rods 10 are rotatably arranged in the gantry 6. The two screw rods 10 are both in the vertical direction and are spaced apart. The screw rod 10 is threadedly provided with a slider 11 that is slidably matched with the gantry 6 and connected to the bottom rod 9. The slider 11 slides in the vertical direction, and the two ends of the bottom rod 9 are respectively fixedly connected to the two sliders 11. The screw rod 10 and the winding roller 7 are connected by a bevel gear assembly 12. The bevel gear assembly 12 includes two meshing bevel gears, and the two bevel gears are respectively fixed on the screw rod 10 and the winding roller 7;

[0029] Referring to the above, when in use, the winding roller 7 is driven to rotate to roll up or loosen the partition curtain 8. At the same time, the two screw rods 10 are driven to rotate together through the two bevel gear assemblies 12 respectively, and the two sliders 11 slide together in the vertical direction due to the action of the threads. The bottom rod 9 moves with the two sliders 11, so that the height of the channel can be adjusted according to the size of the circuit board, thereby improving the flexibility and applicability of use.

[0030] like Figure 3 As shown, in some embodiments, two guide rollers 13 are rotatably disposed in the door frame 6 and are both rollingly overlapped with the partition curtain 8, and the two guide rollers 13 are both horizontal and spaced apart;

[0031] With reference to the above, when the winding roller 7 winds up or loosens the partition curtain 8, the two guide rollers 13 guide and limit the partition curtain 8 together to prevent the partition curtain 8 from being skewed and interfering.

[0032] like Figure 7 As shown, in some embodiments, the furnace body 1 is provided with a driving member that acts on the two winding rollers 7 and drives the two to rotate synchronously;

[0033] With reference to the above, when in use, the two winding rollers 7 are driven to rotate synchronously by a driving member to achieve synchronous adjustment of the heights of the two channels, which improves the synchronization of use and makes the operation more convenient.

[0034] like Figure 7 As shown, in some embodiments, the driving member includes a driving motor 14 arranged in the cooling zone 5, the driving motor 14 is fixed in the cooling zone 5 and the output shaft is in a horizontal direction, the two winding rollers 7 are connected by a pulley assembly 15, the pulley assembly 15 includes two pulleys and a connecting belt, the two pulleys are fixed on the two winding rollers 7, the connecting belt is wound on the two pulleys, the output shaft of the driving motor 14 is connected to one of the winding rollers 7 by a gear pair 16, the gear pair 16 includes two meshing gears, the two gears are fixed on the output shaft of the driving motor 14 and one of the winding rollers 7;

[0035] Referring to the above, when in use, the drive motor 14 works, the output shaft rotates, and one of the winding rollers 7 is driven to rotate through the gear pair 16, and the two winding rollers 7 are rotated synchronously through the pulley assembly 15. By arranging the drive motor 14 in the cooling zone 5, the heat dissipation effect of the drive motor 14 when working can be improved.

[0036] like Figure 3-Figure 5 As shown, in some embodiments, the second partition member includes a fixed tube 17 arranged on the gantry 6, the fixed tube 17 is horizontally oriented and fixedly arranged on the gantry 6, the free end of the fixed tube 17 passes through the furnace body 1, and a conical air duct 18 is arranged on the bottom rod 9, the air duct 18 is horizontally oriented and fixedly arranged on the bottom rod 9, the fixed tube 17 and the air duct 18 are connected through a plurality of hoses 19, and the plurality of hoses 19 are arranged in an array along the length direction of the fixed tube 17;

[0037] Referring to the above, when in use, nitrogen is filled into the fixed tube 17, and the nitrogen enters the wind tube 18 through multiple hoses 19. Thereafter, the nitrogen is blown out from the wind tube 18 into the channel and forms a wind wall. The wind wall can reduce the possibility of nitrogen diffusing from the reflow zone 4 to the preheating zone 3 and the cooling zone 5, and reduce the possibility of air diffusing from the preheating zone 3 and the cooling zone 5 to the reflow zone 4, thereby partitioning the channel without affecting the normal passage of the circuit board. When the bottom rod 9 moves, it drives the wind tube 18 to move together, and the hose 19 can keep the fixed tube 17 and the wind tube 18 always connected.

[0038] like Figure 3-Figure 4As shown, in some embodiments, the inner diameters of the multiple hoses 19 decrease successively along the length direction of the fixed tube 17. The closer to one end of the fixed tube 17 that passes through the furnace body 1, the smaller the inner diameter of the hose 19, and vice versa. This design can make the nitrogen flow rate and flow rate discharged through the multiple hoses 19 basically consistent, so that the wind wall can remain continuous and stable, and play a better partitioning role.

[0039] like Figure 5 As shown, in some embodiments, a three-way pipe 20 is provided on the furnace body 1, and the three-way pipe 20 is fixed on the furnace body 1, and two ends of the three-way pipe 20 are respectively connected to two fixed pipes 17;

[0040] Referring to the above, when in use, nitrogen is filled into the three-way pipe 20, and the nitrogen is split into two streams in the three-way pipe 20, and the two streams of nitrogen enter the two fixed pipes 17 respectively, so there is no need to fill nitrogen into the two fixed pipes 17 separately, which is more convenient to use.

[0041] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A double-track nitrogen furnace for PCB circuit board reflow soldering, comprising a furnace body (1), the furnace body (1) being provided with a double-track conveying device (2), the furnace body (1) being configured with a preheating zone (3), a reflow zone (4) and a cooling zone (5) which are sequentially distributed, characterized in that: A first partitioning member is provided at the entrance and the exit of the reflow zone (4), the first partitioning member comprising a gantry (6), a winding roller (7) is provided on the gantry (6), a partitioning curtain (8) is wound around the winding roller (7), a bottom rod (9) is provided at the free end of the partitioning curtain (8), a channel for the circuit board to pass through is formed between the bottom rod (9) and the double-track conveying device (2), and a second partitioning member acting on the channel is provided on the gantry (6) and the bottom rod (9).

2. The double-track nitrogen furnace for PCB circuit board reflow according to claim 1, characterized in that: The winding roller (7) is rotatably arranged on the portal frame (6), two screw rods (10) are rotatably arranged inside the portal frame (6), a slider (11) is threadedly arranged on the screw rod (10) and is slidably matched with the portal frame (6) and connected to the bottom rod (9), and the screw rod (10) and the winding roller (7) are transmission-connected via a bevel gear assembly (12).

3. The double-track nitrogen furnace for PCB circuit board reflow according to claim 2, characterized in that: Two guide rollers (13) are rotatably arranged in the door-shaped frame (6) and are both in rolling overlap with the partition curtain (8).

4. The double-track nitrogen furnace for PCB circuit board reflow according to claim 2, characterized in that: The furnace body (1) is provided with a driving member which acts on the two winding rollers (7) and drives the two rollers to rotate synchronously.

5. The double-track nitrogen furnace for PCB circuit board reflow according to claim 4, characterized in that: The driving member comprises a driving motor (14) arranged in the cooling zone (5); the two winding rollers (7) are connected to each other via a pulley assembly (15); and the output shaft of the driving motor (14) is connected to one of the winding rollers (7) via a gear pair (16).

6. The double-track nitrogen furnace for PCB circuit board reflow according to claim 2, characterized in that: The second partition member comprises a fixed pipe (17) arranged on the door-shaped frame (6), and a conical air cylinder (18) is arranged on the bottom rod (9), and the fixed pipe (17) and the air cylinder (18) are connected via a plurality of hoses (19).

7. The double-track nitrogen furnace for PCB circuit board reflow according to claim 6, characterized in that: The inner diameters of the plurality of hoses (19) decrease in sequence along the length direction of the fixed tube (17).

8. The double-track nitrogen furnace for PCB circuit board reflow according to claim 6, characterized in that: The furnace body (1) is provided with a three-way pipe (20), and two ends of the three-way pipe (20) are respectively connected to the two fixed pipes (17).

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