Nitrogen protection device and flow guide device and wave soldering equipment

Abstract

The present application belongs to the technical field of welding, and particularly relates to a nitrogen protection device, a flow guide device and a wave-soldering equipment. The nitrogen protection device comprises a nitrogen protection cover and a nitrogen pipe. The nitrogen protection cover is surrounded above a tin bath. The nitrogen pipe comprises first, second and third spray pipes for spraying nitrogen. The first spray pipe is located between the nitrogen protection cover and a turbulence wave. The second spray pipe is located between the turbulence wave and a laminar wave. The third spray pipe is located between the laminar wave and the nitrogen protection cover. The flow guide device comprises a wind deflector located below a wind distribution plate. In the direction of the travel of the circuit board, the wind deflector is located downstream of a preheating fan, and the wind deflector is arranged in an inclined manner. The preheating section of the wave-soldering equipment is provided with the flow guide device, and the welding section is provided with the nitrogen protection device. The present application can reduce the oxygen content during welding and improve the welding quality.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of welding, in particular, the present application relates to a nitrogen protection device, a flow guide device and a wave soldering equipment. BACKGROUND

[0002] Wave soldering refers to that the molten soft solder (mainly tin) is sprayed into a designed solder wave peak by an electric pump or an electromagnetic pump, so that the circuit board pre-installed with components passes through the solder wave peak, and the soldering between the component soldering end or pin and the circuit board pad is realized.

[0003] The wave soldering equipment mainly comprises a spraying machine and a soldering equipment. The spraying machine can adjust the spraying shape and the spraying flow. The soldering equipment comprises a plurality of preheating sections and a soldering section. The preheating mode of the preheating section is hot air heating.

[0004] The working process of the wave soldering equipment is as follows: the circuit board is sent into the spraying machine by a conveying guide rail, and is sent into the soldering equipment after being sprayed with flux by the spraying machine. In the soldering equipment, the circuit board is first heated by the preheating section, and then is sent into the soldering section for soldering after being heated. After the soldering is completed, the conveying guide rail takes the circuit board to a cooling place for cooling. After being cooled, the circuit board is sent out of the wave soldering equipment by the conveying guide rail.

[0005] In the preheating section, the wave soldering equipment is provided with a preheating fan which blows hot air. The upper side of the preheating fan is covered with a wind distribution plate with uniform holes, which can make the hot air blow into the preheating section uniformly from below. The wind distribution plate is located below the conveying guide rail, and the material of the wind distribution plate is usually stainless steel, and the axis of the holes on the wind distribution plate is in the vertical direction, which is easy to make the hot air containing oxygen overflow into the soldering section.

[0006] In the soldering section, the wave soldering equipment is provided with a tin tank, and the liquid tin in the tin tank forms a wave with a parabolic shape, and the wave peak of the wave is in contact with the circuit board for soldering. During soldering, the liquid tin is easy to be oxidized, which affects the soldering quality. SUMMARY

[0007] In order to solve the above problems, the present application provides a nitrogen protection device, a flow guide device and a wave soldering equipment, and the technical scheme is as follows:

[0008] A nitrogen protection device for a soldering section of a soldering apparatus, comprising a nitrogen protection cover and a nitrogen pipe; the nitrogen protection cover is arranged above a soldering tank to reduce the oxygen content above the liquid tin surface; the nitrogen pipe comprises a first nozzle, a second nozzle and a third nozzle for spraying nitrogen; the first nozzle is located between the nitrogen protection cover and a turbulence wave to reduce the oxygen content when the circuit board approaches; the second nozzle is located between the turbulence wave and a laminar wave to reduce the oxygen content between the turbulence wave and the laminar wave; the third nozzle is located between the laminar wave and the nitrogen protection cover to reduce the oxygen content when the circuit board moves away.

[0009] The nitrogen protection device as described above, further preferably: the distance between the first nozzle and the front wall of the turbulence wave is 15-40mm; the distance between the second nozzle and the front wall of the laminar wave is 20-30mm; the distance between the third nozzle and the rear wall of the laminar wave is 10-30mm.

[0010] The nitrogen protection device as described above, further preferably: the front end of the first nozzle, the front end of the second nozzle and the front end of the third nozzle are connected to an air inlet pipe for supplying nitrogen to the first nozzle, the second nozzle and the third nozzle; the air inlet pipe is provided with a bending part, which is immersed in the liquid tin to preheat the nitrogen.

[0011] The nitrogen protection device as described above, further preferably: the first nozzle and / or the second nozzle and / or the third nozzle comprises a diffusion pipe and a sleeve pipe, the sleeve pipe is sleeved on the outside of the diffusion pipe; the diffusion pipe is provided with diffusion holes on the circumferential surface for spraying nitrogen, and the sleeve pipe is provided with an air outlet for blowing nitrogen into the nitrogen protection cover.

[0012] The nitrogen protection device as described above, further preferably: the diffusion holes are arranged in a circumferential array on the circumferential surface of the diffusion pipe.

[0013] The nitrogen protection device as described above, further preferably: the air outlet is located at the lower part of the sleeve pipe, the air outlet is perpendicular to the liquid tin surface, and the width of the air outlet is 1-4mm.

[0014] The nitrogen protection device as described above, further preferably: further comprising a detection probe, the detection probe is located above the second nozzle for detecting the oxygen content; the vertical interval between the detection probe and the second nozzle is 50-150mm.

[0015] The nitrogen protection device as described above is further preferably characterized in that the bottom of the nitrogen protection cover is provided with an opening, the outer contour of the opening has an enclosed area greater than the area of the soldering region on the tin bath, the outer contour of the opening has an enclosed area less than the area of the liquid surface on the tin bath, and the opening can be immersed below the liquid surface on the tin bath to form a liquid seal.

[0016] The nitrogen protection device as described above is further preferably characterized in that the nitrogen protection cover is provided with a conveying inlet on the side wall near the circuit board inlet and a conveying outlet on the side wall near the circuit board outlet, and the upper portion and / or the lower portion of the conveying inlet and / or the conveying outlet is provided with a shielding curtain, the bottom edge of the shielding curtain is flush with the top surface of the circuit board, and / or the top of the shielding curtain is flush with the bottom surface of the circuit board.

[0017] The nitrogen protection device as described above is further preferably characterized in that the shielding curtain comprises multiple layers of flexible baffles, the flexible baffles are provided with multiple baffle strips, and the baffle strips on adjacent flexible baffles are staggered.

[0018] The nitrogen protection device as described above is further preferably characterized in that the conveying inlet and / or the conveying outlet is provided with a baffle, the baffle is below the conveying guide rail, and the baffle cooperates with the shielding curtain to form a seal.

[0019] A flow guide device for a preheating section of a soldering device, comprising a wind shield, the wind shield is below a wind distribution plate, in the direction of the circuit board, the wind shield is downstream of a preheating fan, the wind shield is inclined, gradually extending from the bottom end to the top end towards the preheating fan, for guiding the hot air on the wind distribution plate to blow in the opposite direction of the circuit board.

[0020] The flow guide device as described above is further preferably characterized in that it further comprises an auxiliary wind shield, in the direction of the circuit board, the auxiliary wind shield is downstream of the wind shield, the auxiliary wind shield is inclined, the inclination direction is consistent with the inclination direction of the wind shield.

[0021] The nitrogen protection device as described above is further preferably characterized in that the bottom end of the auxiliary wind shield is rotatably connected to the wave soldering device, for adjusting the inclination angle of the auxiliary wind shield.

[0022] The nitrogen protection device as described above is further preferably characterized in that the auxiliary wind shield has a spacing between the top end of the auxiliary wind shield and the wind distribution plate as an adjustment space of the auxiliary wind shield.

[0023] The nitrogen protection device as described above is further preferably characterized in that it further comprises an additional wind shield, the additional wind shield is above the conveying guide rail and between the preheating fan and the soldering section, and the additional wind shield is inclined, gradually extending from the top end to the bottom end towards the preheating fan.

[0024] Preferably, the top end of the additional baffle is rotatably connected to the wave soldering equipment, and is used to adjust the inclination angle of the additional baffle.

[0025] Preferably, the shortest distance between the bottom of the additional baffle and the circuit board is not less than 80 mm.

[0026] The wave soldering equipment comprises a spraying machine and a soldering equipment, and the preheating section of the soldering equipment is provided with the flow guide device; and the soldering section of the soldering equipment is provided with the nitrogen protection device.

[0027] Compared with the prior art, the advantages and beneficial effects of the present application are as follows:

[0028] 1. In the nitrogen protection device of the present application, the nitrogen protection cover encloses a relatively closed space above the tin tank, which can reduce the air flow above the liquid tin, thereby reducing the oxygen content above the liquid tin surface. The first spray pipe can reduce the oxygen content when the circuit board approaches; the second spray pipe can reduce the oxygen content between the turbulent wave and the flat wave; the third spray pipe can reduce the oxygen content when the circuit board moves away, and the nitrogen pipe can further reduce the oxygen content in the nitrogen protection cover. The nitrogen protection cover and the nitrogen pipe cooperate with each other to reduce the static oxygen content and the dynamic oxygen content in the soldering section during soldering, thereby improving the soldering quality.

[0029] 2. In the flow guide device of the present application, the wind shield can guide the hot air of the preheating fan, so that the hot air is inclined upward when generated, and the inclination direction is opposite to the direction of the circuit board, thereby reducing the diffusion of oxygen from the conveying inlet into the nitrogen protection cover.

[0030] 3. In the wave soldering equipment of the present application, the flow guide device cooperates with the nitrogen protection device to improve the soldering quality of the wave soldering equipment. The wave soldering equipment of the present application first realizes that under the condition of a preheating fan frequency of 40 Hz and a nitrogen input flow of 16.2 m 3 / h, the static oxygen content in the nitrogen protection cover is reduced to below 300 ppm, and the dynamic oxygen content is stably controlled below 3000 ppm. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 Fig. 1 is a structural schematic view of the nitrogen protection device of the present application.

[0032] Figure 2 Fig. 2 is a structural schematic view of the flow guide device of the present application.

[0033] Figure 3 Fig. 3 is a sectional schematic view of the diffusion pipe and the sleeve pipe of the present application.

[0034] In the figure: 1 - shielding curtain; 2 - turbulence wave; 3 - circuit board; 4 - nitrogen protection cover; 5 - conveying guide rail; 6 - third nozzle; 7 - second nozzle; 8 - first nozzle; 9 - baffle; 10 - detection probe; 11 - air distribution plate; 12 - preheating fan; 13 - wind baffle; 14 - auxiliary baffle; 15 - additional baffle; 16 - diffusion pipe; 17 - sleeve; 18 - diffusion hole. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0036] In the description of the present application, the orientations or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application, and are not required to be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. The terms "connected", "connected" used in the present application should be understood broadly, for example, can be fixed connection, can also be detachable connection; can be directly connected, or indirectly connected through intermediate components. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0037] Please refer to Figures 1 to 3 , wherein, Figure 1 is a structural schematic diagram of the nitrogen protection device of the present application; Figure 2 is a structural schematic diagram of the flow guide device of the present application; Figure 3 is a sectional schematic diagram of the diffusion pipe and sleeve of the present application. As Figure 1 indicated, the arrow points to the direction of travel of the circuit board; as Figure 2 indicated, the arrow points to the running track of the hot air.

[0038] The present application provides a nitrogen protection device applied to the welding section of a welding device, mainly comprising a nitrogen protection cover 4 and a nitrogen pipe. Specifically, in use, the nitrogen protection device is installed on the welding section of the welding device in the wave soldering equipment. The nitrogen protection cover 4 is surrounded above the tin bath, and the nitrogen pipe comprises a first nozzle 8, a second nozzle 7 and a third nozzle 6 for spraying nitrogen. The first nozzle 8 is located between the nitrogen protection cover 4 and the turbulence wave 2, the second nozzle 7 is located between the turbulence wave 2 and the laminar wave, and the third nozzle 6 is located between the laminar wave and the nitrogen protection cover 4.

[0039] When the soldering device is running, the nitrogen protection cover 4 encloses a relatively closed space above the tin tank, which can reduce the air flow above the liquid tin and in turn reduce the oxygen content above the liquid tin surface. The circuit board 3 is carried by the conveying rail 5 into the nitrogen protection cover 4, and then passes through the area where the turbulence wave 2 is located and the area where the laminar wave is located. The turbulence wave 2 and the laminar wave divide the space in the nitrogen protection cover 4 into three areas, as shown in Figure 1 The first nozzle 8 sprays nitrogen in the first area, the second nozzle 7 sprays nitrogen in the second area, and the third nozzle 6 sprays nitrogen in the third area. The first nozzle 8 can reduce the oxygen content when the circuit board 3 approaches; the second nozzle 7 can reduce the oxygen content between the turbulence wave 2 and the laminar wave; and the third nozzle 6 can reduce the oxygen content when the circuit board 3 moves away, thereby the nitrogen pipe can reduce the oxygen content in the nitrogen protection cover 4. In the present application, the nitrogen protection cover 4 and the nitrogen pipe cooperate with each other to reduce the static oxygen content and the dynamic oxygen content in the welding section during welding, thereby improving the welding quality.

[0040] As an improvement of the present application, as shown in Figures 1 to 3 The present application also provides the following improved schemes:

[0041] In the present application, the distance between the first nozzle 8 and the front wall of the turbulence wave 2 is 15mm to 40mm, for example, it can be 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, 31mm, 32mm, 33mm, 34mm, 35mm, 36mm, 37mm, 38mm, 39mm, 40mm, it can also be a decimal value between integers 15.5mm, 16.5mm, 17.5mm, 18.5mm, 19.5mm, 20.5mm, 21.5mm, 22.5mm, 23.5mm, 24.5mm, 25.5mm, 26.5mm, 27.5mm, 28.5mm, 29.5mm, 30.5mm, 31.5mm, 32.5mm, 33.5mm, 34.5mm, 35.5mm, 36.5mm, 37.5mm, 38.5mm, 39.5mm. The distance between the second nozzle 7 and the front wall of the adiabatic wave is 20mm to 30mm, for example, it can be 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, it can also be a decimal value between integers 20.5mm, 21.5mm, 22.5mm, 23.5mm, 24.5mm, 25.5mm, 26.5mm, 27.5mm, 28.5mm, 29.5mm. The distance between the third nozzle 6 and the back wall of the adiabatic wave is 10mm to 30mm, for example, it can be 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, it can also be a decimal value between integers 10.5mm, 11.5mm, 12.5mm, 13.5mm, 14.5mm, 15.5mm, 16.5mm, 17.5mm, 18.5mm, 19.5mm, 20.5mm, 21.5mm, 22.5mm, 23.5mm, 24.5mm, 25.5mm, 26.5mm, 27.5mm, 28.5mm, 29.5mm. The first nozzle 8 is at the front end of the turbulence wave 2, and the released nitrogen gas forms a buffer protection layer on the front side of the turbulence wave 2, which isolates the large amount of oxygen carried by the delivery inlet of the nitrogen protection cover 4 from the bottom of the circuit board 3. The second nozzle 7 is between the turbulence wave 2 and the adiabatic wave, and forms a nitrogen isolation layer in the tin liquid separation area on the back side of the turbulence wave 2 and the board (circuit board 3) area on the front side of the adiabatic wave, forming a low-oxygen environment above the wave peak liquid surface.The third nozzle 6 is located at the rear side of the adiabatic wave, and the released nitrogen gas diffuses to insulate and protect the wave surface of the adiabatic wave, and prevents the oxygen at the conveying outlet from interfering with the welding, and can provide a good low-oxygen environment for the separation of the welding point and the tin liquid. The distance between the first nozzle and the front wall of the perturbation wave, the distance between the second nozzle and the front wall of the adiabatic wave, and the distance between the third nozzle and the rear wall of the adiabatic wave are based on the relative position of the wave crest and the nitrogen protection effect, and in this interval, the tin liquid flowing under the wave crest can be prevented from covering the first nozzle, the second nozzle and / or the third nozzle, disturbing the airflow pressure and the spatial distribution of nitrogen, and weakening the protection effect, and the nitrogen concentration in front of the wave crest of the perturbation wave and the adiabatic wave can be ensured.

[0042] In the present application, the front end of the first nozzle 8, the front end of the second nozzle 7, and the front end of the third nozzle 6 are connected to the gas inlet pipe. In use, the gas inlet pipe is used to deliver nitrogen gas to the first nozzle 8, the second nozzle 7, and the third nozzle 6 for spraying. The gas inlet pipe is provided with a bending part which can be immersed in the liquid tin to preheat the nitrogen gas, thereby reducing the oxygen content during welding without affecting the temperature at the welding position.

[0043] In the present application, the first nozzle 8 comprises a diffusion pipe 16 and a sleeve pipe 17, the sleeve pipe 17 being sleeved on the outside of the diffusion pipe 16, the diffusion pipe 16 being provided with diffusion holes 18 on the circumferential surface thereof to uniformly spray nitrogen gas, and the sleeve pipe 17 being provided with a gas outlet to blow nitrogen gas into the nitrogen protection cover 4. The diffusion pipe 16 of the present application is a metal pipe with uniformly distributed nanoscale gas passages to diffuse and spray the gas. In operation, the nitrogen gas is sprayed out of the diffusion holes 18, gathered between the sleeve pipe 17 and the diffusion pipe 16, and then sprayed out of the gas outlet of the sleeve pipe 17. As a preferred embodiment, the diffusion holes 18 are a plurality of diffusion holes arranged in a circumferential array on the circumferential surface of the diffusion pipe 16, which can make the nitrogen gas more uniformly diffuse. The width (L) of the gas outlet is 1mm to 4mm, which can be 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, or 4mm. The gas outlet is located at the lower part of the sleeve pipe 17, and the gas outlet direction of the gas outlet is perpendicular to the liquid tin liquid surface, which can concentrate the gas diffused by the diffusion pipe 16 below the sleeve pipe 17 to flow out in contact with the liquid surface, form a gas protection in the space above the liquid tin, and reduce the generation of oxidation. At the same time, this flow direction of the gas flow can better fit the wave crest climbing to the welding position, and form a good nitrogen protection effect in front of and behind the welding position.

[0044] In the application, the structures of the second nozzle 7 and the third nozzle 6 are the same as that of the first nozzle 8, and each comprises a diffuser pipe 16 and a sleeve pipe 17, the diffuser pipe 16 is provided with diffusion holes 18 on the circumferential surface, the sleeve pipe is provided with a gas outlet, the width (L) of the gas outlet is 1mm to 4mm, the gas outlet is located at the lower part of the sleeve pipe 17, and the gas outlet direction is perpendicular to the liquid tin surface. The structures of the first nozzle 8, the second nozzle 7 and the third nozzle 6 are the same, so as to improve the interchangeability and reduce the storage quantity of spare parts.

[0045] In the application, the detection probe 10 is further included, which is located above the second nozzle 7 and can detect the oxygen content. The vertical spacing between the detection probe 10 and the second nozzle 7 is 50mm to 150mm, for example, it can be 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm, or 55mm, 65mm, 75mm, 85mm, 95mm, 105mm, 115mm, 125mm, 135mm, 145mm, preferably, the detection probe 10 is located 100mm above the second nozzle 7. The measurement accuracy of the detection probe 10 is 1ppm, which can reflect the oxygen concentration in real time during welding. The detection probe 10 is linked with the first nozzle 8, the second nozzle 7 and the third nozzle 6, the nitrogen flow rate of the first nozzle 8, the second nozzle 7 and the third nozzle 6 is adjusted according to the concentration reading of the detection probe 10, so as to control the oxygen concentration in the nitrogen protection cover 4 to a certain level.

[0046] In the application, the bottom of the nitrogen protection cover 4 is provided with an opening, the enclosed area of the outer contour of the opening is greater than the area of the welding area on the tin tank, that is, the opening completely covers the area where the disturbance wave 2 and the advection wave are located. At the same time, the enclosed area of the outer contour of the opening is smaller than the area of the liquid surface on the tin tank. During welding, the tin tank is lifted, the opening can be immersed below the liquid surface on the tin tank, that is, the bottom of the nitrogen protection cover 4 can be completely immersed in the liquid tin to form a liquid seal, which is used in cooperation with the nitrogen pipe, so as to ensure that the static oxygen content in the nitrogen protection cover 4 is below 300ppm, and the dynamic oxygen content (under the condition of continuous passing through the plate when the conveying guide rail 5 travels at a speed of 1200mm / min) is below 3000ppm.

[0047] In the present application, the nitrogen protection cover 4 is provided with a conveying inlet on the side wall close to the entry of the circuit board 3 and a conveying outlet on the side wall close to the exit of the circuit board 3, the conveying inlet is located on the side wall of the nitrogen protection cover 4 close to the preheating section, and the conveying outlet is located on the side wall of the nitrogen protection cover 4 away from the preheating section, which facilitates the entry and exit of the circuit board 3. In order to prevent the oxygen outside the conveying inlet and the conveying outlet of the nitrogen protection cover 4 from diffusing into the nitrogen protection cover 4, the present application is also provided with a shielding curtain 1, which can be arranged at the conveying inlet or the conveying outlet. The shielding curtain 1 can be arranged at the upper part of the conveying inlet, and the bottom edge of the shielding curtain 1 is flush with the top surface of the circuit board; the shielding curtain 1 can be arranged at the lower part of the conveying inlet, and the top of the shielding curtain 1 is flush with the bottom surface of the circuit board; the shielding curtain 1 can be arranged at the upper part of the conveying outlet, and the bottom edge of the shielding curtain 1 is flush with the top surface of the circuit board; the shielding curtain 1 can be arranged at the lower part of the conveying outlet, and the top of the shielding curtain 1 is flush with the bottom surface of the circuit board. As a preferred solution, the shielding curtain 1 is arranged at the conveying inlet and the conveying outlet, and the bottom edge of the shielding curtain 1 is flush with the top surface of the circuit board 3, which can prevent the oxygen at the conveying inlet and the conveying outlet from diffusing into the nitrogen protection cover 4, and will not hinder the movement of the circuit board 3.

[0048] Further, in the present application, the shielding curtain 1 is made of high-temperature resistant material, which can withstand heat cycles and thermal shocks at 100-250℃ for a long time, for example, Teflon high-temperature adhesive tape, which can be used at a temperature of -196℃ to 300℃. The shielding curtain 1 includes multiple layers of flexible baffles, and multiple baffles are arranged on the flexible baffles, the baffles on adjacent flexible baffles are staggered, which can hinder the oxygen from entering the nitrogen protection cover 4 as much as possible, and at the same time, can reduce the interaction between the shielding curtain 1 and the circuit board 3 as much as possible, and reduce the disturbance to the circuit board 3. As an implementable solution, the shielding curtain 1 can be Teflon high-temperature adhesive tape, which is vertically cut multiple times to form baffles.

[0049] Further, in the present application, a baffle 9 is also provided, which is filled below the conveying guide rail 5 and below the shielding curtain 1, which can cooperate with the shielding curtain 1 to play a sealing role. The baffle 9 can be arranged on the conveying inlet or the conveying outlet, and as a preferred solution, the baffle 9 is arranged on the conveying inlet and the conveying outlet, which can cooperate with the shielding curtain 1 to form a seal.

[0050] The application further provides a flow guide device applied to a preheating section of a welding device, mainly comprising a wind baffle 13. Specifically, the wind baffle 13 is located below the air distribution plate 11 and downstream of the preheating fan 12 along the running direction of the circuit board 3. The wind baffle 13 is arranged in an inclined manner and gradually extends towards the preheating fan 12 from the bottom end to the top end, so as to guide the hot air of the preheating fan 12, so that the hot air is blown obliquely when generated, and the oblique direction is opposite to the running direction of the circuit board 3. The obliquely blown hot air is blown to the circuit board 3 after passing through the air distribution plate 11, and the direction is opposite to the running direction of the circuit board 3, so as to reduce the diffusion of oxygen into the nitrogen protection cover 4 from the conveying inlet.

[0051] In the application, an auxiliary baffle 14 is further included, which is located downstream of the wind baffle 13 along the running direction of the circuit board 3. Specifically, the auxiliary baffle 14 is installed below the air distribution plate 11 in the preheating section, and the bottom of the auxiliary baffle 14 is connected with the bottom wall of the inner wall of the preheating section. The auxiliary baffle 14 is arranged in an inclined manner, and the inclination direction is consistent with that of the wind baffle 13, so as to assist the wind baffle 13 to strengthen the running track of the hot air and reduce the amount of oxygen diffused into the nitrogen protection cover 4 from the conveying inlet.

[0052] Further, in the application, the bottom end of the auxiliary baffle 14 is rotatably connected with the wave soldering device, for example, hinged, so that the inclination angle of the auxiliary baffle 14 can be adjusted according to requirements. When the angle of the auxiliary baffle 14 is adjustable, the vertical height of the auxiliary baffle 14 changes during the adjustment. In order to take into account the convenience of adjustment and the accuracy of hot air guiding, in the application, there is a gap between the top end of the auxiliary baffle 14 and the air distribution plate 11, which provides space for the adjustment of the auxiliary baffle 14, and almost no hot air flows.

[0053] In the application, an additional baffle 15 is further included, which is located above the conveying guide rail 5 and between the preheating fan 12 and the welding section. Specifically, the additional baffle 15 is located near the conveying inlet of the nitrogen protection cover 4, and the additional baffle 15 is arranged in an inclined manner and gradually extends towards the preheating fan 12 from the top end to the bottom end, so as to block the hot air carrying oxygen from entering the nitrogen protection cover 4 at the conveying inlet.

[0054] Further, in the application, the top end of the additional baffle 15 is rotatably connected with the wave soldering device, so that the inclination angle of the additional baffle 15 can be adjusted, and the track of the hot air can be controlled according to the actual operation. As a preferred, the shortest distance between the bottom of the additional baffle 15 and the circuit board is not less than 80 mm, so as to facilitate the conveying guide rail 5 to drive the circuit board 3 to pass through.

[0055] Based on the nitrogen protection device and the flow guide device, the application further provides a wave soldering equipment. The wave soldering equipment comprises a spraying machine and a soldering equipment, the preheating section of the soldering equipment is provided with the flow guide device, and the soldering section of the soldering equipment is provided with the nitrogen protection device. The nitrogen protection device can reduce the oxygen content during soldering, and the flow guide device can reduce the oxygen content entering the nitrogen protection cover 4. The flow guide device cooperates with the nitrogen protection device, so that the soldering quality of the wave soldering equipment is improved. The wave soldering equipment of the application realizes, for the first time, that under the condition that the frequency of the preheating fan 12 is 40 Hz and the nitrogen input flow is 16.2 m 3 / h, the static oxygen content in the nitrogen protection cover 4 is reduced to below 300 ppm, and the dynamic oxygen content is stably controlled below 3000 ppm.

[0056] It is to be understood by those skilled in the art that the application can be implemented by other embodiments without departing from the spirit or essential characteristics thereof. Therefore, the above disclosed embodiments are only illustrative in all aspects and are not the only ones. All changes within the scope of the application or within the scope equivalent to the application are included in the application.

Claims

1. A flow directing device for a preheating section of a welding apparatus, characterized in that, Comprising: a wind baffle, which is located below the air distribution plate; in the direction of the circuit board, the wind baffle is located downstream of the preheating fan; the wind baffle is arranged in an inclined manner, gradually extending from the bottom end to the top end towards the preheating fan, for guiding the hot air on the air distribution plate to blow in the opposite direction of the circuit board; further comprising an auxiliary baffle, which is located downstream of the wind baffle in the direction of the circuit board; the auxiliary baffle is arranged in an inclined manner, and the inclination direction is consistent with that of the wind baffle; the bottom end of the auxiliary baffle is rotatably connected to the wave soldering equipment, for adjusting the inclination angle of the auxiliary baffle.

2. The flow guide device according to claim 1, wherein: the top end of the auxiliary baffle and the air distribution plate have a spacing as an adjustment space of the auxiliary baffle.

3. The flow guide device according to claim 1, wherein: further comprising an additional baffle, which is located above the conveying guide rail and between the preheating fan and the soldering section; the additional baffle is arranged in an inclined manner, gradually extending from the top end to the bottom end towards the preheating fan; the top end of the additional baffle is rotatably connected to the wave soldering equipment, for adjusting the inclination angle of the additional baffle; the shortest distance between the bottom of the additional baffle and the circuit board is not less than 80 mm.

4. A wave soldering equipment comprising a spraying machine and a soldering device, wherein: the preheating section of the soldering device is provided with the flow guide device according to any one of claims 1 to 3; the soldering section of the soldering device is provided with a nitrogen protection device; the nitrogen protection device for the soldering section of the soldering device comprises: a nitrogen protection cover and a nitrogen pipe; the nitrogen protection cover is arranged above the tin bath to reduce the oxygen content above the liquid tin surface; the nitrogen pipe comprises a first nozzle, a second nozzle and a third nozzle for spraying nitrogen; the first nozzle is located between the nitrogen protection cover and the turbulence wave, for reducing the oxygen content when the circuit board approaches; the second nozzle is located between the turbulence wave and the laminar wave, for reducing the oxygen content between the turbulence wave and the laminar wave; the third nozzle is located between the laminar wave and the nitrogen protection cover, for reducing the oxygen content when the circuit board moves away; the distance between the first nozzle and the front wall of the turbulence wave is 15 mm to 40 mm; the distance between the second nozzle and the front wall of the laminar wave is 20 mm to 30 mm; the distance between the third nozzle and the rear wall of the laminar wave is 10 mm to 30 mm.

5. The wave soldering equipment according to claim 4, wherein: the front end of the first nozzle, the front end of the second nozzle and the front end of the third nozzle are connected to an air inlet pipe, which is used to transport nitrogen to the first nozzle, the second nozzle and the third nozzle; a bending part is arranged on the air inlet pipe, which is immersed in the liquid tin to preheat the nitrogen.

6. The wave soldering equipment according to claim 4, wherein: the first nozzle and / or the second nozzle and / or the third nozzle comprises a diffusion pipe and a sleeve, and the sleeve is sleeved on the outside of the diffusion pipe. The diffusion pipe is provided with diffusion holes on the circumferential surface for spraying nitrogen, and the sleeve pipe is provided with gas outlets for blowing nitrogen into the nitrogen protection cover. The diffusion holes are in a plurality and are distributed in a circumferential array on the circumferential surface of the diffusion pipe. The gas outlets are located at the lower part of the sleeve pipe, the gas outlet direction is perpendicular to the liquid tin surface, and the width of the gas outlet is 1mm to 4mm.

7. The wave soldering equipment according to claim 4, characterized in that: a detection probe is further included, which is located above the second nozzle and is used for detecting oxygen content; the vertical interval between the detection probe and the second nozzle is 50mm to 150mm.

8. The wave soldering equipment according to claim 4, characterized in that: the bottom of the nitrogen protection cover is provided with an opening, and the enclosed area of the outer contour of the opening is larger than the area of the soldering area on the tin bath; the enclosed area of the outer contour of the opening is smaller than the area of the liquid surface on the tin bath; the opening can be immersed below the liquid surface on the tin bath to form a liquid seal.

9. The wave soldering equipment according to claim 4, characterized in that: the nitrogen protection cover is provided with a conveying inlet on the side wall near the circuit board inlet and a conveying outlet on the side wall near the circuit board outlet; the upper part and / or the lower part of the conveying inlet and / or the conveying outlet is provided with a shielding curtain, the bottom edge of the shielding curtain is flush with the top surface of the circuit board, and / or the top of the shielding curtain is flush with the bottom surface of the circuit board; the shielding curtain includes a plurality of flexible baffles, and the flexible baffles are provided with a plurality of baffle strips, and the baffle strips on adjacent flexible baffles are staggered; the conveying inlet and / or the conveying outlet is provided with a baffle, which is located below the conveying guide rail and is used for cooperating with the shielding curtain to form a seal.

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