Multi-air-duct heating device

Abstract

The invention provides a multi-air-duct heating device. The multi-air-duct heating device comprises a heating cavity and a plurality of heating mechanisms. A bearing platform for placing a workpiece to be heated is arranged at the bottom of the heating cavity; the multiple heating mechanisms are connected to the heating cavity, each heating mechanism comprises a fan assembly, an air supply pipeline, a heating piece, an airflow adjusting valve and an air nozzle, the air supply pipeline extends to the position above the bearing platform from the top of the heating cavity, the fan assembly is arranged at the end, away from the bearing platform, of the air supply pipeline, and the air nozzle is arranged at the end, close to the bearing platform, of the air supply pipeline; the heating piece is arranged in the air supply pipeline and located between the fan assembly and the air nozzle, and the airflow adjusting valve is connected to the air nozzle. The heating mechanisms are designed in a modularized and independent mode, so that each heating mechanism forms an air duct, different areas of a to-be-heated workpiece on the bearing platform can be independently heated in a targeted mode, accurate temperature control over local areas of a BGA chip is achieved, and the welding quality is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of welding, and more particularly to a multi-air duct heating device. Background Art

[0002] In the BGA (ball grid array) welding process, ensuring that the welding area is heated evenly and reaches the appropriate temperature is crucial to the welding quality. Traditional BGA welding heating methods mostly use overall heating equipment, such as hot air reflow ovens. Although this method can heat the entire circuit board to achieve the welding of BGA chips, it has obvious defects: for example, the position, size and distribution of surrounding components of BGA chips on the circuit board are different, and overall heating is difficult to accurately control the temperature of local areas of BGA. At the same time, different BGA chips have different requirements for welding temperature curves. Unified overall heating cannot meet these diverse needs, and problems such as loose welding, cold welding, and short circuits often occur. Summary of the invention

[0003] The purpose of the present invention is to overcome the defects of the prior art and provide a multi-duct heating device to solve the technical problem that the existing BGA soldering temperature is single and cannot be locally regulated.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] The present invention provides a multi-duct heating device, which includes: a heating cavity and a plurality of heating mechanisms; a supporting platform for placing a workpiece to be heated is provided at the bottom of the heating cavity; a plurality of the heating mechanisms are connected to the heating cavity, the heating mechanism includes a fan assembly, an air supply duct, a heating element, an air flow regulating valve and an air nozzle, the air supply duct extends from the top of the heating cavity to above the supporting platform, the fan assembly is arranged at one end of the air supply duct away from the supporting platform, the air nozzle is arranged at one end of the air supply duct close to the supporting platform, the heating element is arranged in the air supply duct and is located between the fan assembly and the air nozzle, and the air flow regulating valve is connected to the air nozzle.

[0006] Wherein, there is an angle between the air nozzle and the vertical plane.

[0007] Among them, the fan assembly includes: a blast drive and a wind wheel; the wind wheel is connected to the output shaft of the blast drive, and the blast drive is used to drive the wind wheel to rotate; a plurality of wind guide blades are provided on the wind wheel, and the plurality of wind guide blades are spirally distributed on the wind wheel, and one end of the wind guide blade close to the center of the wind wheel is lower than the other end.

[0008] Among them, a heat insulation component is provided between two adjacent heating mechanisms, and the heat insulation component includes a heat insulation part and a lifting drive part. The heat insulation part is provided between two adjacent heating mechanisms, and the lifting drive part is used to drive the heat insulation part to perform lifting actions.

[0009] Wherein, the surface of the thermal insulation member is provided with a reflective coating.

[0010] Wherein, a sealing mechanism is provided at the air outlet end of the air nozzle, the air nozzle is penetrated through the sealing mechanism, and the sealing mechanism is used to form a sealed heating space with the workpiece to be heated.

[0011] Wherein, the sealing mechanism includes: a sealing cover and a sealing drive assembly; the sealing cover is provided with a through hole, the air nozzle is passed through the through hole, and the side of the sealing cover away from the air nozzle is open and is used to cover the heating area of ​​the workpiece to be heated; the sealing drive assembly is connected to the heating cavity and is used to drive the sealing cover to approach or move away from the workpiece to be heated.

[0012] Wherein, a main suction piece is sleeved on the outer side of the air nozzle, and the main suction piece is arranged in a ring shape. The main suction piece is provided with an annular suction groove for sucking hot air overflowing from the heating space.

[0013] Wherein, a plurality of auxiliary suction pieces are arranged on the periphery of the supporting platform, and the plurality of auxiliary suction pieces are used for sucking the hot air in the heating cavity.

[0014] Among them, a plurality of thermocouples are embedded on the supporting platform, and the thermocouples are used to detect the local temperature of the workpiece to be heated; an infrared thermal imager is provided on the top of the heating cavity to detect the surface temperature of the workpiece to be heated.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention modularizes and independently designs the heating mechanism so that each heating mechanism forms an air duct, which can independently and targetedly heat different areas of the workpiece to be heated on the supporting platform, thereby realizing precise temperature control of the local area of ​​the BGA chip; by arranging a fan assembly, a heating element and an air flow regulating valve between the two in the heating mechanism, the heating mechanism can flexibly adjust the air supply volume, heating power and air flow size to meet the diverse requirements of different BGA chips for the welding temperature curve; the hot air is transmitted to the corresponding heating area through the air nozzle, so that during the BGA welding process, the heat can be more evenly and concentratedly distributed in the core heating area, effectively reducing problems such as loose welding, cold welding, short circuit, etc., and significantly improving the welding quality.

[0016] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the overall structure of a multi-duct heating device provided by the present invention;

[0018] Figure 2 A schematic diagram of the top view of a multi-duct heating device provided by the present invention;

[0019] Figure 3 for Figure 2 Schematic diagram of the cross-sectional structure at AA.

[0020] Reference numerals:

[0021] 1. Heating cavity; 11. Supporting platform; 2. Heating mechanism; 21. Fan assembly; 211. Blower drive; 212. Wind wheel; 22. Air supply duct; 23. Heating element; 24. Air flow regulating valve; 25. Air nozzle; 3. Heat insulation assembly; 31. Heat insulation element; 32. Lifting drive; 4. Sealing mechanism; 41. Sealing cover; 42. Sealing drive assembly; 421. Sealing drive; 422. Pressing plate; 423. Connecting element; 5. Main suction element; 6. Auxiliary suction element. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is further described in detail in conjunction with the accompanying drawings and specific implementation methods. The technical solution in the embodiment of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0024] It should also be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, the singular forms "a", "an" and "the" are intended to include plural forms unless the context clearly indicates otherwise.

[0025] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0026] See also Figure 1-3 As shown, this embodiment discloses a multi-duct heating device, which is applied to a BGA soldering furnace, and heats a BGA chip or a circuit board carrying a BGA chip to heat a workpiece, so that the solder ball melts to achieve soldering.

[0027] Specifically, the multi-duct heating device of this embodiment includes: a heating cavity 1 and a plurality of heating mechanisms 2; a supporting platform 11 for placing the workpiece to be heated is provided at the bottom of the heating cavity 1; the plurality of heating mechanisms 2 are connected to the heating cavity 1, the heating mechanism 2 includes a fan assembly 21, an air supply duct 22, a heating element 23, an air flow regulating valve 24 and an air nozzle 25, the air supply duct 22 extends from the top of the heating cavity 1 to above the supporting platform 11, the fan assembly 21 is arranged at one end of the air supply duct 22 away from the supporting platform 11, the air nozzle 25 is arranged at one end of the air supply duct 22 close to the supporting platform 11, the heating element 23 is arranged in the air supply duct 22 and is located between the fan assembly 21 and the air nozzle 25, and the air flow regulating valve 24 is connected to the air nozzle 25.

[0028] The multi-duct heating device of this embodiment, by modularizing and independently designing the heating mechanism 2, makes each heating mechanism 2 form an air duct, which can independently and targetedly heat different areas of the workpiece to be heated on the supporting platform 11, and realize accurate temperature control of the local area of ​​the BGA chip; by arranging a fan assembly 21, a heating element 23 and an air flow regulating valve 24 located therebetween in the heating mechanism 2, the heating mechanism 2 can flexibly adjust the air supply volume, heating power and air flow size to meet the diverse requirements of different BGA chips for the welding temperature curve; the hot air is transmitted to the corresponding heating area through the air nozzle 25, so that during the BGA welding process, the heat can be more evenly and concentratedly distributed in the core heating area, effectively reducing problems such as loose welding, cold welding, short circuit, etc., and significantly improving the welding quality.

[0029] Specifically, the nozzle 25 is at an angle to the vertical plane. The tilted setting of the nozzle 25 can change the airflow direction of the hot air, help direct the hot air to the heating area, concentrate the airflow, avoid direct impact of the airflow with the workpiece to be heated, and reduce the instantaneous heat loss and uneven distribution caused by the impact of the airflow.

[0030] In this embodiment, the nozzle 25 is at an angle of 5°-10° to the vertical plane. The nozzle 25 outlet is inclined at 5°-10°, so that the hot air flows to the center of the BGA chip rather than the lateral area, and the solder balls in the center of the BGA chip can be heated in a targeted manner, thereby preventing the outer ring solder balls at the edge of the BGA chip from being affected by the chaotic airflow, thereby ensuring the soldering quality of the BGA chip.

[0031] In this embodiment, the aperture of the air outlet of the air nozzle 25 is 1-2mm. BGA chips are usually installed on compact circuit boards with limited surrounding space. The 1-2mm air nozzle 25 has a smaller aperture, which can better adapt to this tiny space, and is convenient for arranging multiple air nozzles 25 in a limited space, so as to achieve independent heating and precise control of different areas of the BGA chip. The BGA chip is small in size and the solder ball spacing is also small. The air nozzle 25 with an aperture of 1-2mm can concentrate the hot air in a smaller heating area, accurately align the BGA solder ball array, and achieve precise heating of a small area such as the center area of ​​the BGA chip, avoiding heat diffusion to other areas, thereby improving the accuracy and efficiency of heating, and helping to ensure the quality of welding. The small aperture of the air outlet of the air nozzle 25 makes the air flow speed relatively high, which can cover the surface of the BGA chip more evenly, reduce the temperature gradient, and enable each solder ball on the heating area to melt under the same temperature conditions, thereby improving the consistency and reliability of welding.

[0032] Specifically, the relatively arranged air nozzles 25 are staggered. In this embodiment, the staggered distance of the relatively arranged air nozzles 25 is 50% of the aperture. The staggered arrangement of the air nozzles 25 effectively avoids direct airflow collision, prevents the blown airflows from interfering with each other and causing turbulence, and ensures uniform heat distribution.

[0033] Specifically, the fan assembly 21 includes: a blast drive 211 and a wind wheel 212; the wind wheel 212 is connected to the output shaft of the blast drive 211, and the blast drive 211 is used to drive the wind wheel 212 to rotate; the wind wheel 212 is provided with a plurality of wind guide blades (not marked in the figure), and the plurality of wind guide blades are spirally distributed on the wind wheel 212, and one end of the wind guide blade close to the center of the wind wheel 212 is lower than the other end. The blast drive 211 drives the wind wheel 212 to rotate, and the spirally distributed wind guide blades on the wind wheel 212 rotate accordingly. The wind guide blades are distributed on the fan in a spiral shape that is inclined inward and downward. When the wind wheel 212 rotates, the air is guided by the wind guide blades and flows faster along the spiral path, forming a spiral airflow that enters the air supply duct 22 downward.

[0034] In this embodiment, the blade inclination angle of the air guide blade is 15°-30°. Specifically, the air guide blade is inclined 15°-30° compared to the horizontal plane, forcing the airflow to form a vortex and spray downward. According to CFD simulation verification, the air guide blade with a blade inclination angle of 15°-30° and a spiral distribution can reduce the amount of hot air mixing between adjacent air ducts by 40%-60%, which helps to reduce the lateral diffusion of the airflow, ensures energy utilization, and facilitates improving the welding efficiency of the workpiece to be heated.

[0035] Specifically, adjacent heating mechanisms 2 adopt an alternating pulse air supply mode. Different heating mechanisms 2 work intermittently, which can effectively reduce the mixing of hot air between adjacent heating mechanisms 2. In specific implementation, when one heating mechanism 2 is supplying air, the adjacent heating mechanism 2 is in a state of stopping air supply, thereby avoiding the mutual interference of airflows caused by simultaneous air supply, and achieving physical isolation of hot airflows through time difference. Through CFD simulation analysis, compared with simultaneous continuous air supply, this mode can reduce the amount of hot air mixing between adjacent heating mechanisms 2 by about 30%-40%, significantly improving the local accuracy of heating.

[0036] Specifically, the pulse frequency of the heating mechanism 2 is 10-20Hz. When the pulse frequency of the heating mechanism 2 is 10-20Hz, its pulse frequency matches the thermal inertia. Among them, the pulse frequency is the frequency of the alternating air supply of the heating mechanism 2, that is, the number of times the air supply and air supply cycle is completed and stopped per second; thermal inertia is the slow response characteristic of the workpiece to be heated and its surrounding heating environment to temperature changes. Due to the existence of thermal inertia, too high or too low pulse frequency may cause excessive temperature fluctuations. If the frequency is too high, the heat will not be evenly distributed in time before the air is supplied again, which will make the local temperature too high. If the frequency is too low, it will cause insufficient heat supply and the temperature will drop too quickly. At a frequency of 10-20Hz, it can match the thermal inertia well, so that the temperature remains relatively stable during the entire heating process, so that the temperature fluctuation is controlled within a very small range of ±1°C, which can reduce defects such as cold soldering and short circuit caused by temperature fluctuations during welding.

[0037] Specifically, a heat insulation assembly 3 is provided between two adjacent heating mechanisms 2. The heat insulation assembly 3 includes a heat insulation member 31 and a lifting drive member 32. The heat insulation member 31 is provided between two adjacent heating mechanisms 2. The lifting drive member 32 is used to drive the heat insulation member 31 to perform lifting actions. The heat insulation member 31 is a physical barrier between adjacent heating mechanisms 2, which can block the heat generated by adjacent heating mechanisms 2 to prevent the heat from flowing and affecting each other, thereby ensuring that each heating mechanism 2 can independently and accurately heat the target heating area, thereby improving the accuracy of local heating. The lifting drive member 32 drives the heat insulation member 31 to rise or fall according to the operating status of the equipment, and the heat insulation member 31 falls to block the interference of heat from the adjacent heating mechanism 2.

[0038] In this embodiment, when the heating temperature difference of adjacent heating mechanisms 2 is greater than 50°C, the lifting drive 32 drives the heat insulation 31 to descend between the adjacent heating mechanisms 2. When the temperature difference exceeds 50°C, the heat in the high temperature area is easy to diffuse to the low temperature area, causing the temperature of the low temperature area to rise, which is easy to affect the heating accuracy of the low temperature area. After the heat insulation 31 descends, it can form a physical barrier between the two to prevent the disordered conduction of heat, ensure that the heat in the high temperature area is concentrated in the target area, and the low temperature area is heated according to the established temperature curve, so as to ensure that the heating process of each area is not interfered by the adjacent area, thereby improving the accuracy and consistency of welding and reducing welding defects caused by temperature deviation. In addition, the disordered diffusion of heat leads to energy waste. The heat insulation 31 effectively blocks heat transfer, so that the heat generated by each heating mechanism 2 is fully utilized for the heating of the corresponding heating area, avoiding the ineffective flow of heat between different areas, reducing the extra energy consumed to maintain a specific temperature, improving the energy utilization efficiency of the entire heating device, and reducing production costs.

[0039] In this embodiment, the lifting drive member 32 is an electric cylinder. The electric cylinder uses a stepper motor to drive the lead screw nut to achieve the linear motion of the thermal insulation member 31. The stepper motor can convert the electrical pulse signal into angular displacement. Every time a pulse signal is received, the stepper motor rotates a fixed angle to drive the thermal insulation member 31 to rise and fall to a specified height, so that the lifting position of the thermal insulation member 31 can be accurately controlled; and when the stepper motor runs at a low speed, it can still maintain a stable output torque without jitter or loss of step, which is conducive to ensuring the smooth lifting of the thermal insulation member 31 to avoid impact on surrounding components or causing heat disturbance, and further ensure the stability of the heating process and the welding quality. It can be understood that in other embodiments, cylinders or hydraulic cylinders can be used instead of electric cylinders.

[0040] In this embodiment, the movable distance of the heat insulating member 31 is 0-10 mm. The heat insulating member 31 moves within the range of 0-10 mm, and will not occupy too much internal space of the heating cavity 1. The shorter moving distance can meet the requirements of the heat insulation function, and will not affect the layout and installation of other components due to the excessive size or wide moving range of the heat insulating member 31, thereby ensuring the compactness of the internal structure of the multi-duct heating device and improving the overall space utilization and integration of the multi-duct heating device.

[0041] Specifically, the thermal insulation 31 is provided with a plurality of partition holes (not marked in the figure). Preferably, the aperture of the partition holes is 2-3 mm, and the thickness of the thermal insulation 31 is 5-8 mm. The provision of a plurality of partition holes makes the thermal insulation 31 present a honeycomb structure. When the transverse airflow contacts the honeycomb thermal insulation 31, it will be divided by the numerous partition holes, so that the airflow no longer flows directly along the original transverse path, but enters the interior of the partition holes. The flow direction of the airflow in the partition holes becomes chaotic and no longer has a clear transverse directionality, thereby greatly reducing the transverse heat convection; and the airflow flows in the narrow partition holes, and rubs against the hole walls of the partition holes many times, causing the kinetic energy of the airflow to be continuously lost, and the heat it carries is also partially transferred to the thermal insulation 31 in contact with the hole walls, causing the energy of the airflow to gradually decay. Even when the hot airflow reaches the adjacent heating area, the temperature has been greatly reduced and the flow rate has also slowed down, making it difficult to cause obvious interference to the heating process of the adjacent heating area.

[0042] Preferably, the thermal insulation 31 is made of high temperature resistant stainless steel or ceramic-based composite material. For example, the high temperature resistant stainless steel is 310S, which is an austenitic chromium-nickel stainless steel that can withstand a high temperature of 1000°C; for another example, the ceramic-based composite material is SiC fiber-reinforced ceramic. When the multi-duct heating device is working, the temperature inside the heating cavity 1 is relatively high, and the thermal insulation 31 is in a high temperature environment for a long time. The stainless steel or ceramic-based composite material can ensure that the thermal insulation 31 does not soften or deform at high temperatures, and can continuously and stably play a role in thermal insulation, thereby ensuring effective heat isolation between adjacent heating mechanisms 2, maintaining precise heating of each heating area, and thus improving the BGA welding quality.

[0043] Specifically, a reflective coating is provided on the surface of the heat insulating member 31. The reflective coating makes the heat insulating member 31 reflective, and can reflect heat, so that the lost heat is refocused to the current heating area, and the reflective coating further improves the heat insulation effect, reduces energy loss, and improves welding efficiency and welding effect.

[0044] Preferably, the reflective coating is made of a gold film material. The gold film has an infrared reflectivity of more than 95%, and can reflect back most of the heat radiation leaking from the heating area, preventing the heat from penetrating the thermal insulation member 31 and transferring to adjacent areas.

[0045] Specifically, a phase change material is embedded in the thermal insulation 31. Phase change material refers to a material that undergoes a physical state change as the temperature changes, and absorbs or releases a large amount of latent heat in the process. In this embodiment, the phase change material absorbs the overflow heat through a solid-liquid phase change. When heat crosstalk occurs between adjacent heating mechanisms 2, the phase change material in the thermal insulation 31 can quickly absorb the overflow heat, prevent it from continuing to diffuse, maintain the temperature stability of each heating area, and ensure that the BGA is welded under a suitable temperature environment. After absorbing heat, the phase change material will store energy until the temperature drops, and then it will change from liquid to solid and release heat, reducing the impact of heat fluctuations on the welding process.

[0046] Preferably, the phase change material is paraffin or metal composite material with a melting point of 150-200°C. The high temperature of BGA welding is usually 150-200°C. Paraffin or metal composite materials undergo phase change at this temperature, which can absorb or release heat in time, effectively maintain the temperature stability of the heating area, avoid welding defects caused by temperature fluctuations, and improve welding quality. In addition, when the multi-duct heating device is in operation, the temperature changes in each area are complex. The phase change material can flexibly adjust the heat distribution to adapt to the changing welding requirements, and the phase change temperature range of 150-200°C enables the phase change material to play a role in different heating stages. For example, in the initial temperature rise stage of welding, the phase change material absorbs excess heat; in the mid-term temperature maintenance stage of welding, the phase change material maintains the temperature of the heating area stable; in the late cooling stage of welding, the phase change material releases stored heat to assist in cooling.

[0047] Preferably, a heat pipe is embedded in the inner wall of the heat insulating member 31 and / or the heating cavity 1. A heat pipe is a heat transfer element with extremely high thermal conductivity. The heat pipe is filled with a volatile working liquid. Its working principle is based on the vaporization and condensation cycle of the working liquid: at the high temperature end, the working liquid absorbs heat and vaporizes rapidly, and the generated steam flows rapidly to the low temperature end under a small pressure difference; at the low temperature end, the steam releases heat and condenses into liquid when it is cooled, and then flows back to the high temperature end under the action of capillary force or gravity, and the cycle repeats to achieve efficient heat transfer. The heat pipe can recover the latent heat stored in the heating cavity 1 or the heating area during the non-working period of the heating device. The heat pipe recovers the latent heat in time, reduces the temperature inside the heating device, avoids the internal components from being in a high temperature environment for a long time, prolongs the service life of the heating device, and reduces the maintenance cost of the heating device.

[0048] Specifically, a sealing mechanism 4 is provided at the air outlet end of the air nozzle 25, and the air nozzle 25 is inserted through the sealing mechanism 4. The sealing mechanism 4 is used to form a sealed heating space with the workpiece to be heated. The sealing mechanism 4 covers the heating area of ​​the workpiece to be heated, and forms a relatively sealed space with the workpiece to be heated. The hot air blown out by the air nozzle 25 circulates in the sealed heating space to achieve independent heating of the current heating area, reduce the loss of hot air flow to the surrounding environment, improve the heat utilization rate, and thus improve the welding efficiency of the workpiece to be heated.

[0049] Specifically, the sealing mechanism 4 includes: a sealing cover 41 and a sealing drive assembly 42; the sealing cover 41 is provided with a through hole, the air nozzle 25 is inserted through the through hole, and the side of the sealing cover 41 away from the air nozzle 25 is open, which is used to cover the heating area of ​​the workpiece to be heated; the sealing drive assembly 42 is connected to the heating chamber 1, and is used to drive the sealing cover 41 to approach or move away from the workpiece to be heated. The sealing drive assembly 42 is used to drive the sealing cover 41 to move up and down, so that the sealing drive assembly 42 can dynamically adjust the contact pressure between the sealing cover 41 and the workpiece to be heated, so that the sealing cover 41 can adapt to the surface unevenness of the workpiece to be heated, ensure the sealing of the sealed heating space, and also enable the sealing cover 41 to be separated from the workpiece to be heated after heating is completed, ensuring the normal loading and unloading operations of the workpiece.

[0050] Specifically, the sealing drive assembly 42 includes: a sealing drive member 421, a pressing plate 422 and a connecting member 423; the connecting member 423 is connected to the end of the sealing cover 41 away from the supporting platform 11, the pressing plate 422 is connected to the end of the connecting member 423 away from the sealing cover 41, and the sealing drive member 421 is used to drive the pressing plate 422 to perform a lifting action; the connecting member 423 is elastic, and the connecting member 423 is provided with a perforation corresponding to the through hole, and the air nozzle 25 is sequentially penetrated through the perforation and the through hole. The elastic connecting member 423 can automatically deform according to the ups and downs of the workpiece surface when the sealing cover 41 approaches the workpiece. When a part of the sealing cover 41 contacts a higher position on the workpiece surface, the elastic connecting member 423 is locally compressed and contracted, ensuring that the sealing cover 41 can fit tightly with each position of the surface of the workpiece to be heated, maintaining good sealing of the sealed heating space, ensuring that the hot air is concentrated in the heating area, and improving the heating efficiency and welding quality.

[0051] In this embodiment, the sealing driving member 421 is a cylinder, and the cylinder drives the pressing plate 422 to move by a gas pressure of 0.1-0.3 MPa. It is understandable that in other embodiments, hydraulic cylinders or electric cylinders may be used instead of cylinders according to actual needs.

[0052] Specifically, the sealing cover 41 and the connector 423 are made of high temperature resistant elastic material. Preferably, the sealing cover 41 and the connector 423 are made of a graphite and ceramic fiber composite material. Graphite has good properties such as high temperature resistance, self-lubrication and chemical stability, and ceramic fiber has excellent high temperature resistance and heat insulation performance. The composite of the two can complement each other. In the application of the sealing cover 41 and the connector 423 of the multi-duct heating device, the graphite and ceramic fiber composite material enables the sealing cover 41 and the connector 423 to work stably in a high temperature environment, ensuring the sealing effect and structural stability of the sealing mechanism 4.

[0053] Specifically, the main suction piece 5 is sleeved on the outside of the air nozzle 25. The main suction piece 5 is arranged in an annular shape and is provided with an annular suction groove (not marked in the figure) for sucking the hot air overflowing from the heating space. The main suction piece 5 can discharge the hot air overflowing from the corresponding heating area during the heating process, avoid excessive accumulation of hot air in the heating area resulting in uneven temperature distribution, help maintain the temperature stability of the heating area, and improve the welding quality. At the same time, actively extracting hot air can prevent the adjacent heating mechanism 2 from being disturbed by the heat of the current heating mechanism 2, further ensuring the independence of the heating mechanism 2 and the heating accuracy.

[0054] In this embodiment, the main suction member 5 is sleeved outside the connecting member 423, and the vertical height of the main suction member 5 is less than the vertical height of the connecting member 423. The main suction member 5 is restricted by the sealing cover 41 and the pressing plate 422, and is not easy to be separated from the air nozzle 25, which not only avoids the pressing plate 422 blocking the main suction member 5 from being isolated from the air nozzle 25, but also can directly absorb the hot air overflowing from the sealed heating space, further ensuring the heat absorption effect. It is understandable that in other embodiments, the main suction member 5 can be installed on the side of the pressing plate 422 close to the air nozzle 25.

[0055] Specifically, a plurality of auxiliary suction pieces 6 are provided on the periphery of the supporting platform 11, and the auxiliary suction pieces 6 are used to suck the hot air in the heating cavity 1. The auxiliary suction pieces 6 can discharge the hot air in the heating cavity 1, and avoid excessive accumulation of hot air in the heating cavity 1, which may cause the components to be damaged by heat, and help to extend the service life of the heating device. At the same time, the auxiliary suction pieces 6 actively extract the hot air, which can avoid the heat from flowing between adjacent heating mechanisms 2, and further ensure the heating effect of each heating mechanism 2. The sealing cover 41, the main suction piece 5, the auxiliary suction piece 6, the air guide blades, and the isolation piece interact with each other to form a multi-layer isolation system for the heating mechanism 2, so that the heating mechanism 2 can independently and accurately control the temperature of the heating area, reduce temperature deviation and temperature interference, improve welding quality, and at the same time reduce energy loss, extend the service life of the equipment, and provide a solid guarantee for efficient and stable welding process. More specifically, the sealing cover 41 forms a local enclosed space to reduce the loss of hot air, allowing the heat to be concentrated on the workpiece to be heated, and preventing heat from overflowing and interfering with the adjacent heating mechanism 2; the main suction piece 5 surrounds the air nozzle 25, and promptly extracts the hot air overflowing from the heating space, maintains the temperature stability of the current heating area, and reduces the thermal impact on the surrounding area and the adjacent heating mechanism 2; the auxiliary suction piece 6 sucks the hot air in the heating cavity 1, further reducing the crosstalk of heat between adjacent heating mechanisms 2, and ensuring that each heating mechanism 2 can operate in a relatively independent thermal environment; the wind guide blades make the airflow entering the air duct flow downward in a spiral shape, reducing the lateral flow of the airflow, and thereby reducing the airflow interference with the adjacent heating mechanism 2; the isolation piece physically blocks the heat conduction between the adjacent heating mechanisms 2, so that the heat is retained in the current heating area.

[0056] Specifically, the main suction member 5 and the auxiliary suction member 6 are connected to the vacuum pump respectively. More specifically, in actual application, the vacuum pump can actively suck the overflowing hot air through the negative pressure of 0.5-1kPa, provide reliable power for sucking the hot air, ensure that each heating area is stably heated according to the preset temperature curve, improve the heating performance and welding effect of the heating device as a whole, and improve the product qualification rate and production efficiency.

[0057] Specifically, a number of thermocouples (not shown) are embedded on the support platform 11, and the thermocouples are used to detect the local temperature of the workpiece to be heated; an infrared thermal imager (not shown) is provided on the top of the heating cavity 1 to detect the surface temperature of the workpiece to be heated. The thermocouples on the support platform 11 are in direct contact with the workpiece to be heated, and detect the local temperature of the workpiece in real time. In specific implementation, the thermocouples can be set at positions corresponding to the heating area to accurately detect the temperature changes in the heating area; the infrared thermal imager on the top of the heating cavity 1 generates a surface temperature image of the workpiece to be heated by detecting the infrared radiation emitted from the surface of the workpiece to be heated. Thermocouples provide accurate local temperature data, and the infrared thermal imager presents the surface temperature distribution of the workpiece as a whole. The combination of the two enables the operator and the control system to fully and accurately grasp the temperature changes of the workpiece to be heated during the welding process, facilitates timely adjustment of the heating parameters, ensures that the welding process is carried out under appropriate temperature conditions, and effectively improves the welding quality and success rate.

[0058] In this embodiment, the thermocouple is a K-type thermocouple with a diameter of 0.1 mm, and the infrared thermal imager is a FLIRA6750sc infrared thermal imager. The workpiece to be heated is small in size, and the K-type thermocouple with a diameter of 0.1 mm has a small volume, can accurately contact a smaller area of ​​the workpiece to be heated, and obtain high-precision local temperature data; the FLIRA6750sc infrared thermal imager has a high resolution, an accuracy of up to ±1°C, and can perform a comprehensive scan of the workpiece to be heated on the top of the heating chamber 1, generate an accurate surface temperature image, and present the overall temperature distribution.

[0059] A multi-duct heating device of the present embodiment, by modularizing and independently designing the heating mechanism, each heating mechanism forms an air duct, which can independently and targetedly heat different areas of the workpiece to be heated on the supporting platform, thereby realizing precise temperature control of the local area of ​​the BGA chip; by arranging a fan assembly, a heating element and an air flow regulating valve located therebetween in the heating mechanism, the heating mechanism can flexibly adjust the air supply volume, heating power and air flow size to meet the diverse requirements of different BGA chips for the welding temperature curve; the hot air is transmitted to the corresponding heating area through the air nozzle, so that during the BGA welding process, the heat can be more evenly and concentratedly distributed in the core heating area, effectively reducing problems such as loose welding, cold welding, short circuit, etc., and significantly improving the welding quality.

[0060] The above examples are only used to further illustrate the technical content of the present invention, so that readers can understand it more easily, but they do not mean that the implementation of the present invention is limited to this. Any technical extension or re-creation made according to the present invention is protected by the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A multi-duct heating device, characterized in that: include: A heating cavity and a plurality of heating mechanisms; a supporting platform for placing the workpiece to be heated is provided at the bottom of the heating cavity; a plurality of the heating mechanisms are connected to the heating cavity, the heating mechanism comprises a fan assembly, an air supply duct, a heating element, an air flow regulating valve and an air nozzle, the air supply duct extends from the top of the heating cavity to above the supporting platform, the fan assembly is arranged at one end of the air supply duct away from the supporting platform, the air nozzle is arranged at one end of the air supply duct close to the supporting platform, the heating element is arranged in the air supply duct and between the fan assembly and the air nozzle, and the air flow regulating valve is connected to the air nozzle.

2. The multi-duct heating device according to claim 1, characterized in that: There is an angle between the air nozzle and the vertical plane.

3. The multi-channel heating device according to claim 2, characterized in that: The fan assembly includes: a blast drive and a wind wheel; the wind wheel is connected to the output shaft of the blast drive, and the blast drive is used to drive the wind wheel to rotate; a plurality of wind guide blades are provided on the wind wheel, and the plurality of wind guide blades are spirally distributed on the wind wheel, and one end of the wind guide blade close to the center of the wind wheel is lower than the other end.

4. The multi-duct heating device according to claim 1, characterized in that: A heat insulation component is provided between two adjacent heating mechanisms, and the heat insulation component includes a heat insulation member and a lifting drive member. The heat insulation member is provided between two adjacent heating mechanisms, and the lifting drive member is used to drive the heat insulation member to perform lifting actions.

5. The multi-duct heating device according to claim 4, characterized in that: A reflective coating is provided on the surface of the heat insulation member.

6. The multi-channel heating device according to claim 1, characterized in that: The air outlet end of the air nozzle is provided with a sealing mechanism, the air nozzle is penetrated through the sealing mechanism, and the sealing mechanism is used to form a sealed heating space with the workpiece to be heated.

7. The multi-channel heating device according to claim 6, characterized in that: The sealing mechanism includes: a sealing cover and a sealing drive assembly; the sealing cover is provided with a through hole, the air nozzle is passed through the through hole, and the sealing cover is open on a side away from the air nozzle, so as to cover the heating area of ​​the workpiece to be heated; the sealing drive assembly is connected to the heating cavity, so as to drive the sealing cover to approach or move away from the workpiece to be heated.

8. The multi-channel heating device according to claim 1, characterized in that: A main suction piece is sleeved on the outer side of the air nozzle. The main suction piece is arranged in an annular shape and is provided with an annular suction groove for sucking hot air overflowing from the heating space.

9. The multi-channel heating device according to claim 8, characterized in that: A plurality of auxiliary suction pieces are arranged on the periphery of the supporting platform, and the plurality of auxiliary suction pieces are used for sucking the hot air in the heating cavity.

10. The multi-channel heating device according to claim 1, characterized in that: The supporting platform is embedded with a plurality of thermocouples, which are used to detect the local temperature of the workpiece to be heated; the top of the heating cavity is provided with an infrared thermal imager, which is used to detect the surface temperature of the workpiece to be heated.

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