High-uniformity step-by-step heating device

Abstract

The invention provides a high-uniformity step-by-step heating device which comprises a plurality of heating modules, and a partition cavity is formed between every two adjacent heating modules. Each heating module is provided with a heat source cavity and a heating cavity, the heating cavities and the heat source cavities are communicated through backflow channels, the backflow channels comprise two partition backflow channels and two inner backflow channels, the two inner backflow channels are arranged in the transverse direction, and the two partition backflow channels are arranged in the longitudinal direction; a conveying opening is formed between the heating cavity and the partition cavity and used for allowing a circuit board to pass through. A partition backflow channel is arranged at the conveying opening and is in a slit shape extending in the transverse direction, the vertical end of the partition backflow channel is located at the conveying opening, the other end of the partition backflow channel communicates with the heat source cavity, airflow vertically flowing into the heat source cavity can be formed in the conveying opening through the partition backflow channel, and then an air wall is formed to prevent air at the conveying opening from flowing in the longitudinal direction. Air flow and heat interference at the conveying port are reduced, and the heating efficiency is improved.

Description

[0001] This application is a divisional application. The application number of the original application is: "202310532950.8", the application date is: "May 11, 2023", and the name of the invention is: "High-efficiency and precision temperature control reflow soldering equipment". Technical Field

[0002] The present invention relates to the technical field of circuit board welding, and in particular to a high-uniformity step-by-step heating device. Background Art

[0003] Reflow soldering is a process in which the circuit board with solder is heated to melt the solder and flow and infiltrate again, and then the circuit board is cooled to solidify the solder, thus completing the soldering process of the circuit board.

[0004] During the heating process, the circuit board typically passes through multiple heating modules, with the heating temperatures gradually increasing, gradually raising the board to soldering temperature. Because the circuit boards need to enter and exit the heating modules, they are equipped with a delivery port. At this port, the heat from adjacent heating modules interferes with each other, resulting in temperature differences at different locations within the same heating module. This results in uneven heating of the circuit board within the same heating module, making it difficult to reach the preset temperature, affecting solder joint quality and production efficiency. Summary of the Invention

[0005] The present invention provides a highly uniform step-by-step heating device, which can improve heating efficiency, thereby ensuring solder joint quality and improving production efficiency.

[0006] The present invention provides a high-uniformity step-by-step heating device, comprising a plurality of heating modules, wherein the plurality of heating modules are arranged at intervals in the longitudinal direction, and a partition cavity is provided between two adjacent heating modules; each of the heating modules is provided with a heat source cavity and a heating cavity, wherein the heat source cavity is used to provide heat energy and transport it to the heating cavity; the heating cavity and the heat source cavity are connected via a return channel, wherein the return channel comprises a partition return channel and an inner return channel, wherein both the partition return channel and the inner return channel are two, the two inner return channels are arranged in the transverse direction, and the two partition return channels are arranged in the longitudinal direction. ; A conveying port is formed between the heating chamber and the partition chamber, and the conveying port is used for the circuit board to pass through; the partition return channel is provided at the conveying port, and the partition return channel is in the shape of a slit extending in the transverse direction, and one end of the partition return channel in the vertical direction is located at the conveying port, and the other end is connected to the heat source chamber, so as to form an airflow flowing vertically into the heat source chamber at the conveying port, and then form a wind wall to block the air at the conveying port from flowing longitudinally, thereby reducing the air flow and heat interference between the heating chamber and the partition chamber at the conveying port.

[0007] Wherein, the heating module includes a heater, and the heater includes a shell, a heat-saturating component, a heating component and a heating fan;

[0008] The heat-sinking assembly is fixed to the outer shell, and includes an inner shell, an air outlet plate, and a heat-sinking plate; the inner shell and the outer shell are both in the shape of a cube with one side open, and the openings of the two are in the same direction; the inner shell is fixed in the outer shell, and the heat source cavity is formed between the two; the partition return flow channel is located between the openings of the inner shell and the outer shell; the air outlet plate is fixed at the opening of the inner shell, and a heat-sinking cavity is formed between the two; the heat-sinking plate is located in the heat-sinking cavity, and the heat-sinking plate is parallel to and spaced apart from the air outlet plate, and a plurality of through holes are provided on both the air outlet plate and the heat-sinking plate;

[0009] The heating component is arranged in the heat source cavity to provide heat energy;

[0010] The heating fan is fixed to the outer shell, the air inlet of the heating fan is located in the heat source cavity, and the air outlet is connected to the heat equalizing cavity through a hot air duct, and the hot air duct has an air outlet end facing the heat equalizing plate, and the air outlet end is located on the side of the heat equalizing plate away from the air outlet plate, and the air outlet end is spaced apart from the heat equalizing plate.

[0011] The heaters are arranged in pairs, and the pair of heaters are arranged vertically and symmetrically, and the space between the pair of heaters forms the heating cavity.

[0012] Wherein, the hole density of the air outlet plate is smaller than the hole density of the heat spreader.

[0013] Wherein, the air outlet height of the air outlet plate is 20mm-30mm.

[0014] Wherein, the through hole on the air outlet plate is a tapered hole, and the end with a larger hole diameter faces the inner shell.

[0015] Among them, the hot air duct is arranged vertically to form a vertically flowing hot air flow; the opening area of the air outlet end is smaller than the area of the heat spreader; on the projection of the heat spreader and the air outlet end on the horizontal plane, the four edges of the heat spreader protrude from the air outlet end.

[0016] In which, a partition return plate and a partition plate are provided at the entrance of the partition return channel, the partition return plate and the partition plate are connected to form an L shape, the side of the partition return plate away from the partition plate is fixedly connected to the inner shell, and a plurality of return holes are provided on the partition return plate, and the plurality of return holes are arranged horizontally; the partition plate is located between the inner shell and the outer shell, and the partition plate divides the return channel into a first sub-channel and a second sub-channel in the longitudinal direction; the first sub-channel is located between the side wall of the inner shell and the partition plate, and is connected to the return hole; the second sub-channel is located between the side wall of the outer shell and the partition plate.

[0017] In which, the partition return channel is divided into a first sub-channel and a second sub-channel in the longitudinal direction; the first sub-channel and the second sub-channel are both slit-shaped; the first sub-channel is closer to the heating chamber than the second sub-channel; in the longitudinal direction, the size of the second sub-channel is smaller than that of the first sub-channel.

[0018] The inlet of the second sub-channel is closer to the heat source cavity than the inlet of the first sub-channel, and the air in the partition cavity can enter the heat source cavity to form a negative pressure in the partition cavity.

[0019] The highly uniform step-by-step heating device provided by the present invention blocks the airflow flowing vertically into the heat source cavity in the return channel, which can drive the air flow at the delivery port, thereby forming an airflow flowing vertically into the heat source cavity at the delivery port, and then forming a wind wall, which can block the air at the delivery port from flowing vertically, reducing the air flow and heat interference between the heating cavity and the partition cavity at the delivery port. The temperature at each position in the same heating cavity is relatively consistent, and it is ensured that the circuit board reaches the preset temperature in the heating cavity, thereby improving the heating efficiency and realizing efficient and precise temperature control, thereby ensuring the quality of the solder joints and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. The drawings described below are only drawings corresponding to some embodiments of the present invention.

[0021] Figure 1 This is a structural diagram of the efficient and precise temperature-controlled reflow soldering equipment provided by the preferred embodiment of the present invention.

[0022] Figure 2 yes Figure 1 A three-dimensional schematic diagram of a longitudinal section of a medium-efficiency, precision temperature-controlled reflow soldering equipment;

[0023] Figure 3 yes Figure 1 Orthographic projection of the longitudinal section of the medium-efficiency precision temperature-controlled reflow soldering equipment;

[0024] Figure 4 yes Figure 1 Schematic diagram of the structural framework of medium-efficiency precision temperature-controlled reflow soldering equipment;

[0025] Figure 5 yes Figure 4 Schematic diagram of the partial framework of adjacent heating modules of medium-efficiency precision temperature-controlled reflow soldering equipment;

[0026] Figure 6 yes Figure 2 Schematic diagram of the structure of the heater of medium-efficient and precise temperature-controlled reflow soldering equipment;

[0027] Figure 7 yes Figure 6 Exploded diagram of the middle heater;

[0028] Figure 8 yes Figure 6 a perspective schematic diagram of a transverse cross-section of the middle heater;

[0029] Figure 9 yes Figure 6 an orthographic projection of a transverse section of the middle heater;

[0030] Figure 10 yes Figure 6 an orthographic projection of a longitudinal section of the middle heater;

[0031] Figure 11 yes Figure 10 Enlarged view of point A in the middle. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0033] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0034] See Figure 1 、 Figure 2 and Figure 3The preferred embodiment of the present invention provides a high-efficiency, precise temperature-controlled reflow soldering device, comprising a sequentially connected step-by-step heating device 100, a cooling device 200, and a recovery device 300. The step-by-step heating device 100 is used to heat and heat the circuit board step by step. The cooling device 200 is provided at the end of the step-by-step heating device 100 and is used to cool the circuit board, thereby completing the reflow soldering operation. The cooling device 200 absorbs the hot air from the circuit board and sends it to the recovery device 300, which is used to recover the flux in the airflow.

[0035] The high-efficiency and precision temperature-controlled reflow soldering equipment also includes a base 801 and a top cover 802. The step-by-step heating device 100, the cooling device 200 and the recovery device 300 are all fixed on the base 801. The top cover 802 is arranged above the step-by-step heating device 100, the cooling device 200 and the recovery device 300, so that the step-by-step heating device 100, the cooling device 200 and the recovery device 300 are in a relatively closed environment to prevent the overflow of gases such as flux.

[0036] In this embodiment, the step-by-step heating device 100, the cooling device 200, and the recovery device 300 are arranged longitudinally and fixed to a base 801. A conveying device 400 is also provided on the base 801. The conveying device 400 is used to carry the circuit board through the step-by-step heating device 100 and the cooling device 200 in sequence. The conveying device can be a conventional and mature conveying device, and the structure of the conveying device 400 is not described in detail in this invention.

[0037] The step-by-step heating device 100 includes multiple heating modules spaced longitudinally, with partition chambers 109 positioned between adjacent modules. Driven by a conveyor 400, circuit boards enter the first end of the step-by-step heating module and pass through the modules, gradually increasing their temperature. This melts the solder and secures the electronic components to the circuit board. The circuit boards then exit the step-by-step heating device 100 and enter the cooling device 200.

[0038] In this embodiment, multiple heating modules are arranged longitudinally. As they approach the cooling device 200, the heating temperature of the heating modules gradually increases, gradually heating to a preset temperature through multiple stages. It should be understood that the horizontal direction X and the longitudinal direction Y referred to in this embodiment are two mutually perpendicular directions on a horizontal plane, both perpendicular to the vertical direction Z.

[0039] like Figure 4 and Figure 5As shown, each heating module is provided with a heat source cavity 102 and a heating cavity 103. The heat source cavity 102 is used to provide heat energy and transport it to the heating cavity 103. The heating cavity 103 is the area for heating the circuit board 901. A conveying port 108 is formed between the heating cavity 103 and the partition cavity 109. The conveying port 108 is used for the circuit board 901 to pass through, so that the circuit board 901 can move between the heating modules; the circuit board 901 can enter the heating cavity 103 from the conveying port 108, and after heating in the heating cavity 103, it can be moved out of the heating cavity 103 from another conveying port 108, and moved into the partition cavity 109, and then enter another heating module through the conveying port 108 of another heating module.

[0040] like Figure 5 As shown, a partition return channel 104 is provided at the delivery port 108. The partition return channel 104 is in the shape of a slit extending in the transverse direction. One end of the partition return channel 104 is located at the delivery port 108 in the vertical direction, and the other end is connected to the heat source chamber 102, so as to form an airflow flowing vertically into the heat source chamber 102 at the delivery port 108. The airflow flowing vertically into the heat source chamber 102 in the partition return channel 104 can drive the air flow at the delivery port 108, thereby forming an airflow flowing vertically into the heat source chamber at the delivery port 108, and then forming a wind wall, which can block the air flow in the vertical direction at the delivery port 108, reducing the air flow and heat interference between the heating chamber 103 and the partition chamber 109 at the delivery port 108. The temperature at each position in the same heating chamber 103 is relatively consistent, and the circuit board 901 is ensured to reach the preset temperature in the heating chamber 103, thereby achieving efficient and precise temperature control, improving heating efficiency and ensuring solder joint quality. At the same time, the isolation return channel 104 can bring the hot air in the heating chamber 103 back to the heat source chamber 102, so that the heat source chamber 102, the heating chamber 103 and the return channel can be connected to form an internal circulation airflow, so that the heat energy can be recycled, saving energy consumption and reducing costs.

[0041] In this embodiment, the heating module includes a heater 10, and a heat source cavity 102 is arranged in the heater 10. The heaters 10 can be arranged in pairs, with a pair of heaters 10 arranged vertically and symmetrically, and the space between the pair of heaters 10 forms a heating cavity 103. Furthermore, the heaters 10 in each heating module are two pairs, that is, the heating module contains four heaters 10, and the two pairs of heaters 10 are arranged vertically. Using multiple heaters 10 can effectively improve the heating efficiency and ensure the uniformity of heating. The structures of the four heaters 10 are similar, and the structure of one heater 10 is used as an example for specific description. Here, in other embodiments, each heater 10 can also be only a pair, with the two heaters 10 arranged vertically; that is, the aforementioned heating modules can be divided into two heating modules; or the heaters 10 are two independent heaters, with the two heaters 10 arranged vertically, and the air outlet surface of the heaters 10 is covered with a cover plate to form a relatively closed heating cavity 103; or, there can be only one heater 10, that is, the heating module has only one heat source cavity 102 and one heating cavity 103.

[0042] like Figure 5 、 Figure 6 、 Figure 7 As shown, the heater 10 includes a housing 11, a heat spreader assembly 12, a heating assembly 13, and a heating fan 14. The housing 11 is used to provide support for the entire heater 10, and the housing 11 can be fixedly connected to the base of a high-efficiency, precision temperature-controlled reflow soldering device. The heat spreader assembly 12 is fixed in the housing 11 to ensure that heat flows to the circuit board more evenly; the heating assembly 13 is arranged in the housing 11 to provide thermal energy; the heating fan 14 is fixed to the housing to drive the air flow in the housing 11 so that the heat energy generated by the heating assembly 13 can flow to the circuit board through the heat spreader assembly 12.

[0043] The heat spreader assembly 12 includes an inner shell 121, an air outlet plate 122 and a heat spreader plate 123. The outer shell 11 and the inner shell 121 are in the shape of a cube with one side open, and the openings of the two are in the same direction. The inner shell 121 is fixed in the outer shell 11, and a heat source cavity 102 is formed between the two. The heating assembly 13 is arranged in the heat source cavity 102 to provide heat energy. The partition return flow channel is located between the openings of the inner shell 121 and the outer shell 11. The opening of the inner shell 121 is used for heat outflow, and the air on one side of the heater 10 can enter the heat source cavity 102 through the gap between the openings of the inner shell 121 and the outer shell 11, so as to be heated again by the heating assembly 13 and flow to one side of the heater 10 through the heat spreader assembly 12, thereby forming a circulating heating to make full use of the heat energy.

[0044] Air outlet plate 122 is fixed to the opening of inner shell 121, forming a heat-saturating chamber 105 between the two. Heat entering inner shell 121 must flow out through air outlet plate 122. A heat-saturating plate 123 is located within heat-saturating chamber 105. Heat-saturating plate 123 and air outlet plate 122 are spaced apart and parallel to each other, and both are provided with multiple through-holes. The air outlet of heating fan 14 is connected to inner shell 121, with air flowing toward heat-saturating plate 123.

[0045] The heating fan 14 is used to provide power for gas flow. Its air inlet 141 is located in the heat source chamber 102, and the air outlet is connected to the heat-equalizing chamber 105 through the hot air duct 142. The heating fan 14 can absorb the heat in the heat source chamber 102, and at the same time, make the air at the circuit board flow back to the heat source chamber 102; after the heating fan 14 inhales the hot air, it flows to the circuit board through the hot air duct 142 and the heat-equalizing component 12. The heat-equalizing component 12 can make the hot air flow evenly to the circuit board, so that all parts of the circuit board are heated evenly. The heating component 13 is located between the air inlet 141 and the inner shell 121 of the heating fan 14, so that the heating component 13 is located between the air inlet 141 and the return channel, so that the air flow needs to be heated by the heating component 13 before entering the air inlet 141.

[0046] The hot air duct 142 has an air outlet end 143 facing the heat vapor chamber 123. The air outlet end 143 is located on the side of the heat vapor chamber 123 away from the air outlet plate 122. The air outlet end 143 is spaced apart from the heat vapor chamber 123 so that the hot air flow can overflow from the edge of the heat vapor chamber 123. The hot air flow sucked in by the heating fan 14 flows to the heat spreader 123 through the hot air duct 142. Part of the hot air passes through the through holes of the heat spreader 123 and flows to the air outlet plate 122, and the other part flows to the air outlet plate 122 from the edges of the heat spreader 123. The heat spreader 123 with multiple through holes can disperse the hot air flow, so that the hot air flow is dispersed and then flows to the air outlet plate 122, so that the wind pressure at each position of the air outlet plate 122 is roughly the same; the dispersed hot air flow flows to the circuit board through the multiple through holes of the air outlet plate 122. The multiple through holes evenly distributed on the air outlet plate 122 can make the hot air flow evenly flow from the air outlet plate 122 to the circuit board, and form an equal pressure uniform air heating structure on the air outlet surface of the air outlet plate 122, so that the heated hot air can be evenly blown out on the entire board surface of the air outlet plate 122, so that the circuit board is evenly heated, the temperature difference is reduced, and the quality of the solder joints is improved. The air outlet height of the air outlet plate 122 is about 20mm-30mm, so that the uniform hot air can just blow to the circuit board, which can achieve the heating effect on the circuit board while avoiding blowing off the circuit board components.

[0047] The multiple through-holes on the air outlet plate 122 and the vapor chamber 123 are evenly arranged in a diamond shape, so that three adjacent through-holes are arranged in an equilateral triangle. The distance between each through-hole is the same, thus achieving a uniform arrangement and improving the air distribution effect. The hole density of the air outlet plate 122 is lower than that of the vapor chamber 123, which can increase the hole density of the vapor chamber 123 to facilitate the flow of hot air through the vapor chamber 123. The lower hole density of the air outlet plate 122 can ensure a relatively uniform distribution of air volume from each through-hole of the air outlet plate 122, reducing the difference in air volume caused by the distance from the vapor chamber 123.

[0048] The through hole on the air outlet plate 122 is a tapered hole, with the larger end facing the inner shell 121. The hot air in the inner shell 121 flows from the thick end to the thin end of the tapered hole, and the speed of the hot air flow will increase, which can bring heat to the circuit board as quickly as possible, thereby improving heating efficiency.

[0049] Hot air duct 142 is arranged vertically to form a vertical hot air flow. The opening area of outlet end 143 is smaller than that of vapor chamber 123. In the horizontal projection of vapor chamber 123 and outlet end 143, the perimeter of vapor chamber 123 protrudes beyond outlet end 143. This ensures that all hot air flowing out of outlet end 143 passes through vapor chamber 123, improving air distribution.

[0050] like Figure 2 As shown, the vapor chamber 123 is square, with its four sides parallel to the four sides of the opening of the inner shell 121, so that the two can fit together. The outlet end 143 of the hot air duct 142 is square, and the vapor chamber 123 and the outlet end 143 are staggered at 45 degrees, so that the corners of the vapor chamber 123 protrude from the edges of the outlet.

[0051] Each heat spreader 123 is fixed to the inner shell 121 by two columns 124. The two columns 124 are located on the outside of the hot air duct 142. The columns 124 can be used to fix the heat spreader 123 in the inner shell 121, and the heat spreader 123 maintains a certain distance from the air outlet end 143 of the hot air duct 142.

[0052] In this embodiment, the inner shell 121 is in the shape of a cuboid, and its opening is rectangular. The air outlet plate 122 is correspondingly in the shape of a rectangular plate, and the length directions of both are horizontal; there are two heat spreaders 123, which are arranged along the length direction of the air outlet plate 122, and there are two corresponding hot air ducts 142, which are respectively provided for the two heat spreaders 123; the two hot air ducts 142 are arranged along the length direction of the air outlet plate 122, and are symmetrically arranged on both sides of the heating fan 14. By utilizing the cooperation of the two heat spreaders 123 and the two hot air ducts 142, the rectangular air outlet plate 122 can discharge air evenly at all positions in the horizontal direction.

[0053] The partition return channel 104 is longitudinally divided into a first sub-channel 1041 and a second sub-channel 1042. Both the first sub-channel 1041 and the second sub-channel 1042 are slit-shaped. The first sub-channel 1041 is closer to the heating chamber 103 than the second sub-channel 1042. The width of the first sub-channel 1041 is greater than the width of the second sub-channel 1042. It is understood that the width here refers to the longitudinal dimension of the sub-channel. In the longitudinal direction, the second sub-channel 1042 is smaller than the first sub-channel 1041.

[0054] The width of the first sub-channel 1041 is greater than the width of the second sub-channel 1042, so that the second sub-channel 1042 forms a narrower slit than the first sub-channel 1041, and the air flow rate in the second sub-channel 1042 is greater than the air flow rate in the first sub-channel 1041, so that two air flows can be formed at the delivery port 108 of the heating chamber 103, thereby improving the stability of the wind wall at the delivery port 108, preventing the air in the partition chamber 109 from entering the heating chamber 103, and thus avoiding the mutual interference of heat between different heating modules. Since the greater the air flow rate, the air pressure at this position is relatively smaller, so that the air pressure near the partition chamber 109 is lower than the air pressure near the heating chamber 103, thereby preventing the air in the partition chamber 109 from directly entering the heating chamber 103, and thus preventing the temperature in the heating chamber 103 from being disturbed by the temperature in the partition chamber 109.

[0055] The surrounding side walls of the outer shell 11 and the surrounding side walls of the inner shell 121 are spaced apart to form a return channel connecting the heating chamber 103 and the heat source chamber 102. The return channel includes a partition return channel 104 and an inner return channel 106. The partition return channel 104 is located between the long side of the outer shell 11 and the long side of the inner shell 121, so that the partition return channel is in the shape of a slit arranged along the horizontal direction. The inner return channel 106 is located between the short side of the outer shell 11 and the short side of the inner shell 121. There are two partition return channels 104 and two inner return channels 106. In the longitudinal direction, the inner shell 121 is located between the two partition return channels 104. In the horizontal direction, the inner shell 121 is located between the two inner return channels 106. In this embodiment, a part of the side wall of the outer shell 11 in the horizontal direction is formed by a part of the support plate set for reflow soldering, and is therefore not shown in the figure.

[0056] A return plate 162 and a partition plate 163 are provided at the entrance of the return channel 104. The return plate 162 and the partition plate 163 are connected in an L-shape. The side of the return plate 162 facing away from the partition plate 163 is fixedly connected to the inner shell 121. The return plate 162 is provided with a plurality of return holes 1620 arranged in a transverse direction. The partition plate 163 is located between the inner shell 121 and the outer shell 11 and longitudinally divides the return channel into a first sub-channel 1041 and a second sub-channel 1042. The first sub-channel 1041 is located between the sidewall of the inner shell 121 and the partition plate 163 and is connected to the return holes 1620. The second sub-channel 1042 is located between the sidewall of the outer shell 11 and the partition plate 163. The partition plate 163 can be used to separate the return flow channel 104 into a first sub-channel 1041 and a second sub-channel 1042. The width of the first sub-channel 1041 is greater than the width of the second sub-channel 1042, that is, the distance between the partition plate 163 and the outer shell 11 is smaller than the distance between the partition plate 163 and the side wall of the inner shell 121.

[0057] In this embodiment, by setting up the partition return channel 104, the partition cavity can play a better partitioning role, and the temperature between two adjacent heating chambers can be guaranteed to be between 40 degrees and 60 degrees. By setting up the first sub-channel and the second sub-channel, the temperature difference can be made to exceed 60 degrees, ensuring that the circuit board can be heated up step by step in stages.

[0058] In this embodiment, the air outlet plate 122 , the partition return plate 162 and the partition plate 163 are integrally formed and formed by bending a plate material to facilitate processing and preparation.

[0059] An inner return plate 161 is provided at the entrance of the inner return channel 106. This inner return plate 161 is provided with a plurality of strip-shaped holes 1610, which are arranged longitudinally, with their lengths extending transversely. These strip-shaped holes 1610 allow air within the heating chamber 103 to enter the inner return channel, with the air flow through the strip-shaped holes 1610 exceeding the flow through the cutoff return channel 104, thereby improving return efficiency. In this embodiment, the inner return plate 161 is fixed to the air outlet plate 122. In other embodiments, the inner return plate 161 can also be directly fixed to the inner shell 121.

[0060] In the same heating module, a support member is provided between two adjacent heaters 10 at the bottom, and the support member is fixedly connected to the two outer shells 11. The support member has two support plates, the top ends of which protrude to block the return plate 162 and are supported below the guide rod, which is used to guide the circuit board 901 conveying device. The support plate can be used to conveniently support the guide rod. The support plate and the side wall of the outer shell 11 are located on the same vertical plane, and the support plate can act as a partition wall, allowing the air in the heating chamber 103 to enter the heat source chamber 102.

[0061] Between two adjacent heating modules, the open ends of the side walls of two adjacent shells 11 are close to the closed end of the shell 11 relative to the partition return plate 162, that is, the entrance of the second sub-channel 1042 is close to the heat source cavity 102 relative to the entrance of the first sub-channel 1041, so that the air in the partition cavity 109 can also enter the heat source cavity 102, forming a negative pressure in the partition cavity 109, thereby preventing the hot air in the heating cavity from entering the partition cavity, avoiding mutual interference with other adjacent heating cavities.

[0062] The cooling device 200 is located at the end of the step-by-step heating device 100 and includes two or more cooling modules spaced longitudinally. Using two or more cooling modules improves cooling efficiency. In this embodiment, there are two cooling modules. The air outlet of the cooling suction blower in the cooling device 200 is connected to the recovery device 300, which is used to recover the solder flux.

[0063] In summary, although the present invention has been disclosed above with reference to preferred embodiments, the above preferred embodiments are not intended to limit the present invention. A person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A high uniformity step-by-step heating device, characterized in that: The invention comprises a plurality of heating modules, the plurality of heating modules are arranged at intervals in the longitudinal direction, and a partition cavity is provided between two adjacent heating modules; each of the heating modules is provided with a heat source cavity and a heating cavity, the heat source cavity is used to provide heat energy and transport it to the heating cavity; the heating cavity and the heat source cavity are connected via a return channel, the return channel comprises a partition return channel and an inner return channel, the partition return channel and the inner return channel are both two, the two inner return channels are arranged in the transverse direction, and the two partition return channels are arranged in the longitudinal direction; the heating cavity and the partition cavity are connected via a return channel. A delivery port is formed between the broken cavities, and the delivery port is used for the circuit board to pass through; the partition return channel is provided at the delivery port, and the partition return channel is in the shape of a slit extending in the transverse direction, and one end of the partition return channel is located at the delivery port in the vertical direction, and the other end is connected to the heat source cavity, so as to form an airflow flowing vertically into the heat source cavity at the delivery port, and then form a wind wall to block the air at the delivery port from flowing longitudinally, thereby reducing the air flow and heat interference between the heating cavity and the partition cavity at the delivery port.

2. The high uniformity step-by-step heating device according to claim 1, characterized in that: The heating module includes a heater, and the heater includes a housing, a heat-saturating component, a heating component and a heating fan; The heat-sinking assembly is fixed to the outer shell, and includes an inner shell, an air outlet plate, and a heat-sinking plate; the inner shell and the outer shell are both in the shape of a cube with one side open, and the openings of the two are in the same direction; the inner shell is fixed in the outer shell, and the heat source cavity is formed between the two; the partition return flow channel is located between the openings of the inner shell and the outer shell; the air outlet plate is fixed at the opening of the inner shell, and a heat-sinking cavity is formed between the two; the heat-sinking plate is located in the heat-sinking cavity, and the heat-sinking plate is parallel to and spaced apart from the air outlet plate, and a plurality of through holes are provided on both the air outlet plate and the heat-sinking plate; The heating component is arranged in the heat source cavity to provide heat energy; The heating fan is fixed to the outer shell, the air inlet of the heating fan is located in the heat source cavity, and the air outlet is connected to the heat equalizing cavity through a hot air duct, and the hot air duct has an air outlet end facing the heat equalizing plate, and the air outlet end is located on the side of the heat equalizing plate away from the air outlet plate, and the air outlet end is spaced apart from the heat equalizing plate.

3. The high uniformity step-by-step heating device according to claim 2, characterized in that: The heaters are arranged in pairs, and the pair of heaters are arranged vertically and symmetrically, and the space between the pair of heaters forms the heating cavity.

4. The high uniformity step-by-step heating device according to claim 2, characterized in that: The hole density of the air outlet plate is smaller than the hole density of the heat spreader.

5. The high uniformity step-by-step heating device according to claim 2, characterized in that: The air outlet height of the air outlet plate is 20mm-30mm.

6. The high uniformity step-by-step heating device according to claim 2, characterized in that: The through hole on the air outlet plate is a tapered hole, with the end with a larger hole diameter facing the inner shell.

7. The high uniformity step-by-step heating device according to claim 2, characterized in that: The hot air duct is arranged vertically to form a vertically flowing hot air flow; the opening area of the air outlet end is smaller than the area of the heat spreader; in the projection of the heat spreader and the air outlet end on the horizontal plane, the four edges of the heat spreader protrude from the air outlet end.

8. The high uniformity step-by-step heating device according to claim 2, characterized in that: A partition return plate and a partition plate are provided at the entrance of the partition return channel, the partition return plate and the partition plate are connected to form an L shape, the side of the partition return plate away from the partition plate is fixedly connected to the inner shell, and a plurality of return holes are provided on the partition return plate, and the plurality of return holes are arranged in the horizontal direction; the partition plate is located between the inner shell and the outer shell, and the partition plate divides the return channel into a first sub-channel and a second sub-channel in the longitudinal direction; the first sub-channel is located between the side wall of the inner shell and the partition plate, and is connected to the return hole; the second sub-channel is located between the side wall of the outer shell and the partition plate.

9. The high uniformity step-by-step heating device according to any one of claims 1 to 7, characterized in that: The partition return channel is divided into a first sub-channel and a second sub-channel in the longitudinal direction; the first sub-channel and the second sub-channel are both slit-shaped; the first sub-channel is closer to the heating chamber than the second sub-channel; in the longitudinal direction, the size of the second sub-channel is smaller than that of the first sub-channel.

10. The high uniformity step-by-step heating device according to claim 9, characterized in that: The inlet of the second sub-channel is closer to the heat source cavity than the inlet of the first sub-channel, and the air in the partition cavity can enter the heat source cavity to form a negative pressure in the partition cavity.

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