A reflow soldering machine

Abstract

The present invention discloses a reflow soldering machine, which includes a machine base, a machine cover, an upper plate mechanism, a transition mechanism, a conveyor chain, a tensioning wheel, a conveyor track, a plurality of temperature control devices, a plurality of cooling devices, a thermal circulation system and a blanking plate. The machine cover is installed on the machine base, the upper plate mechanism is installed at the feed end of the machine base, and the transition mechanism is installed between the machine base and the upper plate mechanism. The present invention provides a switching zone 1 between the preheating zone and the insulation zone, and provides a switching zone 2 between the insulation zone and the reflow zone. The switching zone 1 can be switched to the preheating zone or the insulation zone, and the switching zone 2 can be switched to the insulation zone or the reflow zone to meet the welding heating requirements of different products. At the same time, the thermal circulation system is combined to improve the thermal efficiency of the equipment. The conveyor chain is tensioned by providing a tensioning mechanism, and the tensioning degree of the conveyor chain is kept unchanged to avoid the chain length change during the heating process and ensure welding stability.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit board reflow soldering equipment, in particular to a reflow soldering machine. Background Art

[0002] Reflow oven soldering is a key process in surface mount printed circuit board (PCB) assembly. Its purpose is to heat and melt the pre-printed solder paste on the PCB according to a specific temperature ramp rate and temperature range, completing the soldering process between the PCB and the components. Because the PCB is heated by various temperature zones during reflow, the conveyor speed is a crucial parameter in the process definition. Adjusting this parameter affects the heating rate and the time it takes for the PCB to pass through the reflow oven.

[0003] The existing reflow soldering machine includes four temperature zones: preheating zone, holding zone, reflow zone and cooling zone. Each zone is composed of one or more independent temperature control devices. Since each temperature control device is independent (individually controlled), the flue gas generated during the heating process contains recyclable flux. The flux recovery process requires condensation and recovery of the flue gas. If the high-temperature flue gas generated by heating each temperature control device is directly condensed, its thermal efficiency is low, which greatly increases the energy consumption of the equipment. In order to reduce the energy consumption of the equipment, the existing technology such as patent number: "2012104592362", patent name: "Reflow Soldering System" patent, the reflow soldering system of the patent has a hot air circulation system to improve the reflow soldering Thermal efficiency of the equipment; although this patent reduces the energy consumption of the equipment and improves the utilization rate of thermal energy, when the equipment is welding different products, the heating temperature and heating time in each temperature zone vary accordingly. The heating temperature is easy to control, but the heating time is not easy to control. This is because the speed of the PCB board is the same when the existing reflow soldering machine passes through each temperature zone (using the same chain drive). Therefore, to change the heating time of each temperature zone, the combination of the temperature control device can only be changed to form heating zones of different lengths. However, after changing the combination of the temperature control device, the hot air circulation system of Patent 2012104592362 cannot meet the corresponding changes to adapt to the production needs of different products.

[0004] Secondly, in the process of conveying PCB boards, the chains and tracks pass through multiple temperature zones with different temperatures. Due to thermal expansion and contraction, and the long length of the entire production line, generally more than 5-6 meters, the length of the chain will vary greatly. The change in chain length will cause the chain tension to change, which in turn affects the feeding stability of the PCB boards, easily causing the components on the circuit boards to loosen, resulting in poor welding. In response to the above problems, the present invention provides a solution. Summary of the Invention

[0005] The present invention aims to overcome the defects of the prior art and provide a reflow soldering machine with high thermal efficiency and good stability.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A reflow soldering machine comprises a machine base, a machine cover, an upper plate mechanism, a transition mechanism, a conveyor chain, a tensioning wheel, a conveyor track, a plurality of temperature control devices, a plurality of cooling devices, a heat circulation system and a blanking plate, wherein the machine cover is mounted on the machine base, the upper plate mechanism is mounted on the feed end of the machine base, the transition mechanism is mounted between the machine base and the upper plate mechanism, the temperature control device comprises an upper temperature control device and a lower temperature control device symmetrically arranged above and below the conveyor track, the cooling device comprises an upper cooling device and a lower cooling device symmetrically arranged above and below the conveyor track, a plurality of temperature control devices sequentially form a preheating zone, a holding zone and a reflow zone, a plurality of cooling devices form a cooling zone, one or more temperature control devices between the preheating zone and the holding zone form a switching zone one, and the temperature control device of the switching zone one It can switch between the preheating zone and the insulation zone, and one or more temperature control devices between the insulation zone and the reflow zone constitute the switching zone 2. The temperature control device of the switching zone 2 can switch between the insulation zone and the reflow zone; the thermal circulation system includes a flux recovery device, a circulation outlet pipe, an exhaust gas outlet, a cooling diversion tank, a nitrogen storage tank, a heating storage tank, an insulation storage tank, a preheating storage tank, a confluence tank, a circulation inlet pipe, a pressure relief pipe 1 and a pressure relief pipe 2. The outlet end of the flux recovery device is connected to the air inlet end of the cooling diversion tank through the circulation outlet pipe, and the other branch of the circulation pipe is connected to the exhaust gas outlet. The exhaust gas outlet is equipped with an exhaust gas outlet pipe, and the outlet end of the cooling diversion tank is connected to the air inlet end of the cooling device in the cooling zone, and the outlet end of the cooling device is connected to the heating The air inlet of the hot storage tank is connected, the nitrogen storage tank is connected to the heating storage tank, the air inlet of the temperature control device in the reflux zone is connected to the air outlet of the heating storage tank, the air outlet of the temperature control device in the reflux zone is connected to the air inlet of the insulation storage tank, the air inlet of the temperature control device in the switching zone 2 is connected to the air outlet of the heating storage tank and the air outlet of the insulation storage tank, and a solenoid valve is provided on each of the two connected branches; the air outlet of the temperature control device in the switching zone 2 is connected to the air inlet of the insulation storage tank and the air inlet of the waste heat storage tank, and a solenoid valve is provided on each of the two connected branches, the air inlet of the insulation zone is connected to the air outlet of the insulation storage tank, the air outlet of the insulation zone is connected to the air inlet of the preheating storage tank, and the air inlet of the switching zone 1 is connected to the air outlets of the insulation storage tank and the preheating storage tank. And each of the two connected branches is provided with a solenoid valve, the air outlet end of the switching zone one is connected to the air inlet end of the preheating storage tank and the confluence tank, and each of the two connected branches is provided with a solenoid valve, the air inlet end of the preheating zone is connected to the air outlet end of the preheating storage tank, the air outlet end of the preheating zone is connected to the air inlet end of the confluence tank, the confluence tank is connected to the flux recovery device through a circulation pipe, the insulation storage tank and the preheating storage tank are connected to the flux recovery device through pressure relief pipe one and pressure relief pipe two respectively, and a pressure relief valve is provided on each of the pressure relief pipe one and pressure relief pipe two; the unloading end of the machine base is provided with a horizontal tensioning mechanism installed in a horizontal chute and an inclined tensioning mechanism installed in an inclined chute, and the horizontal tensioning mechanism is connected to the lower plate support roller and the unloading plate where the lower plate sprocket is located;The structure of the inclined tensioning mechanism is the same as that of the horizontal tensioning mechanism, and the inclined tensioning mechanism is connected to both ends of the support roller where the other sprocket is located.

[0008] The lifting mechanism comprises a bottom end of a lifting plate, a bottom end of a lifting plate, and a bottom end of a lifting plate, and the like. The lifting plate is fixed on the lifting plate, and the lifting plate is fixed to the lifting plate. The lifting plate is fixed to the lifting plate, and the lifting plate is fixed to the lifting plate.

[0009] Furthermore, the tensioning valve includes a valve body, a valve chamber, a piston, a one-way valve mechanism and a relief valve mechanism. The piston is installed in the valve chamber of the valve body, the piston is connected to the tensioning rod, the one-way valve mechanism is installed at the liquid inlet of the tensioning valve, and the relief valve mechanism is installed at the liquid outlet of the tensioning valve. The one-way valve mechanism includes an inlet valve block and an inlet spring installed in the one-way valve chamber, and a liquid inlet joint is installed on the liquid inlet of the one-way valve chamber. The relief valve mechanism includes an adjusting bolt, an overflow spring and an overflow valve block installed in the overflow valve chamber, and an overflow joint is installed on the liquid outlet of the overflow valve chamber.

[0010] Furthermore, the upper temperature control device includes a temperature control cover, a temperature control chamber, a motor, a wind wheel, a heating tube, a rectifier plate, a temperature sensor, an air intake chamber, an air intake interface, a reflux chamber and a reflux interface. The temperature control cover is fixedly installed on the machine base or the machine cover, the rectifier plate is installed at one end of the opening of the temperature control chamber, the motor is installed at the other end of the temperature control cover, the wind wheel is installed in the temperature control chamber, and the wind wheel is connected to the motor by transmission, the heating tube and the temperature sensor are installed in the temperature control chamber and below the wind wheel, the air intake chamber is arranged in a shell installed at one end of the temperature control cover with the motor, and the air intake chamber is connected to the temperature control chamber, and the air intake chamber is connected to the pipeline of the heat circulation system through the air intake interface; the reflux chamber is arranged on the side wall of the temperature control cover, and the opening of the reflux chamber is arranged on the side facing the circuit board to be processed, and the reflux chamber is connected to the pipeline of the heat circulation system through the reflux interface.

[0011] Furthermore, except that no heating tube is provided inside the cooling device, the rest of the structure is the same as that of the temperature control device.

[0012] Furthermore, the upper plate mechanism includes an upper plate motor, an upper plate frame, an upper plate conveyor belt and a placement groove. The upper plate frame is composed of two parallel plate-shaped upper plate frames, and each upper plate frame on both sides is equipped with an upper plate conveyor belt arranged on the same horizontal plane. The opposite side of the two upper plate conveyor belts protrudes from the outer edge of the upper plate frame, and the upper plate conveyor belt is transmission-connected to the upper plate motor installed on one side of the upper plate frame. A square placement groove is provided above the loading end of the upper plate frame.

[0013] Furthermore, the transition mechanism includes a connecting frame and a transition roller. The connecting frame is installed between the upper plate frame and the upper plate rail on both sides by bolts. The two ends of the transition roller are installed on the connecting frames on both sides. The two ends of the transition roller are directly larger than the diameter of the middle section, and the upper side sections of the two ends of the transition roller are on the same plane as the belt surface of the upper plate conveyor belt.

[0014] Furthermore, the flux recovery device includes a recovery device shell, an air inlet, a condensation chamber, a condensation pipe, a partition, a recovery chamber, an air outlet, a cooling inlet, a cooling outlet and a recovery port. The interior of the rotary device shell is divided into an upper condensation chamber and a lower recovery chamber by a partition. The upper end of the condensation pipe is located in the condensation chamber, and the lower end extends into the recovery chamber. The recovery hole is arranged at the bottom of the part of the condensation pipe extending into the recovery chamber. The recovery port is arranged at the bottom of the recovery chamber. The two ends of the condensation pipe are respectively connected to the air inlet and the air outlet arranged on the outside of the recovery device shell. The cooling inlet and the cooling outlet are arranged on both sides of the condensation chamber.

[0015] Furthermore, a deoxidizing mechanism is provided on the air outlet of the flux recovery device, and the deoxidizing mechanism includes an outer cover arranged on the outside of the recovery device shell and a deoxidizer filled in the inner cavity of the outer cover.

[0016] In summary, the present invention has the following beneficial effects:

[0017] 1. By setting a switching zone 1 between the preheating zone and the holding zone, and setting a switching zone 2 between the holding zone and the reflow zone, the switching zone 1 can be switched to the preheating zone or the holding zone according to the welding heating needs, and the switching zone 2 can be switched to the holding zone or the reflow zone according to the welding heating needs, so as to meet the welding heating needs of different products. At the same time, combined with the heat circulation system, the thermal efficiency of the equipment is improved and the energy consumption of the equipment is reduced;

[0018] 2. The conveyor chain is tensioned by setting a tensioning mechanism, and the tension of the conveyor chain is kept constant to avoid changes in the length of the chain during the heating process, which in turn affects the tension of the chain, thereby affecting the stability of the conveying and the welding effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention;

[0020] Figure 2 It is a structural diagram of the temperature control device;

[0021] Figure 3 It is a structural diagram of the thermal cycle system;

[0022] Figure 4 It is a structural diagram of a flux recovery device;

[0023] Figure 5 It is a structural diagram of the upper plate mechanism;

[0024] Figure 6 It is a structural diagram of the lower plate mechanism;

[0025] Figure 7 It is a structural diagram of the tensioning mechanism;

[0026] Figure 8 It is a structural diagram of the horizontal tensioning mechanism;

[0027] Figure 9 It is a structural diagram of the tensioning valve.

[0028] In the figure: 1. Machine base; 2. Machine cover; 3. Upper plate frame; 4. Upper plate mechanism; 5. Transition mechanism; 6. Conveyor chain; 7. Tensioner; 8. Upper temperature control device; 9. Lower temperature control device; 10. Upper cooling device; 11. Lower cooling device; 12. Horizontal chute; 13. Inclined chute; 14. Blanking plate; 15. Exhaust pipe; 16. Temperature control cover; 17. Temperature control chamber; 18. Motor; 19. Fan wheel; 20. Heating pipe; 21. Rectifier plate; 22 , temperature sensor; 23, air inlet chamber; 24, air inlet interface; 25, reflux chamber; 26, reflux interface; 27, flux recovery device; 28, circulation outlet pipe; 29, tail gas outlet; 30, cooling diversion tank; 31, nitrogen storage tank; 32, heating storage tank; 33, insulation storage tank; 34, preheating storage tank; 35, confluence tank; 36, circulation inlet pipe; 37, pressure relief pipe 1; 38, pressure relief pipe 2; 39, recovery device shell; 40, air inlet; 41. Condensation chamber; 42. Condensation tube; 43. Partition; 44. Recovery chamber; 45. Recovery hole; 46. Outer cover; 47. Deoxidizer; 48. Air outlet; 49. Cooling inlet; 50. Cooling outlet; 51. Recovery port; 52. Upper plate motor; 53. Upper plate frame; 54. Upper plate conveyor belt; 55. Placement trough; 56. Connecting frame; 57. Transition roller; 58. Feed sprocket; 59. Moving block; 60. Lower plate sprocket; 61. Lower plate support roller ;62. Motor seat;63. Conveying motor;64. Fixing plate;65. Tensioning spring;66. Positioning plate;67. Tensioning rod;68. Tensioning valve;69. Horizontal tensioning mechanism;70. Tilt tensioning mechanism;71. Connecting block;72. Valve body;73. Valve chamber;74. Piston;75. Overflow joint;76. Adjusting bolt;77. Overflow;78. Overflow valve block;79. Liquid inlet joint;80. Liquid inlet valve block;81. Liquid inlet spring. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0030] A reflow soldering machine, such as Figure 1 and Figure 3As shown, it includes a machine base 1, a machine cover 2, an upper plate mechanism 4, a transition mechanism 5, a conveyor chain 6, a tensioning wheel 7, a conveyor track, a plurality of temperature control devices, a plurality of cooling devices, a heat circulation system and a blanking plate 14. The machine cover 2 is installed on the machine base 1, the upper plate mechanism 4 is installed at the feed end of the machine base 1, and the transition mechanism 5 is installed between the machine base 1 and the upper plate mechanism 4. The temperature control device includes an upper temperature control device 8 and a lower temperature control device 9 symmetrically arranged above and below the conveyor track. The structures of the upper and lower temperature control devices are exactly the same and are used to heat the circuit boards to be welded on the conveyor chain 6 up and down. The cooling device includes an upper cooling device 10 and a lower cooling device 11 symmetrically arranged above and below the conveyor track. The structures of the upper and lower cooling devices are the same. Exactly the same, several temperature control devices form a preheating zone, a holding zone and a reflow zone in sequence along the welding production line, and several cooling devices form a cooling zone, which respectively preheat, hold, heat and reflow, and cool the circuit board to be welded. One or more temperature control devices between the preheating zone and the holding zone form a switching zone one, and the temperature control device of the switching zone one can be switched between the preheating zone and the holding zone. One or more temperature control devices between the holding zone and the reflow zone form a switching zone two, and the temperature control device of the switching zone two can be switched between the holding zone and the reflow zone. By changing the length of the preheating zone, the holding zone and the reflow zone through the switching zone one and the switching zone two, the proportion of the time the circuit board passes through each zone is changed, thereby meeting the welding requirements of different products. Figure 3As shown, the thermal circulation system includes a flux recovery device 27, a circulation outlet pipe 28, an exhaust gas discharge port 29, a cooling diversion tank 30, a nitrogen storage tank 31, a heating storage tank 32, an insulation storage tank 33, a preheating storage tank 34, a confluence tank 35, a circulation inlet pipe 36, a pressure relief pipe 1 37 and a pressure relief pipe 2 38. The outlet end of the flux recovery device 27 is connected to the air inlet end of the cooling diversion tank 30 through the circulation outlet pipe 28, and the other branch of the circulation pipe 28 is connected to the exhaust gas discharge port 29. The exhaust gas discharge port 29 is equipped with an exhaust gas discharge pipe 15. The outlet end of the cooling diversion tank 30 is connected to the air inlet end of the cooling zone cooling device. The cooling device The air outlet end is connected to the air inlet end of the heating storage tank 32, the nitrogen storage tank 31 is connected to the heating storage tank 32, the nitrogen storage tank 31 replenishes nitrogen for the heating storage tank 32, so that each heating zone is heated in a nitrogen environment, the air inlet end of the temperature control device of the reflux zone is connected to the air outlet end of the heating storage tank 32, the air outlet end of the temperature control device of the reflux zone is connected to the air inlet end of the insulation storage tank 33, the air inlet end of the temperature control device of the switching zone 2 is connected to the air outlet end of the heating storage tank 32 and the air outlet end of the insulation storage tank 33, and a solenoid valve is provided on each of the two connected branches. The two solenoid valves are used to control the air inlet end of the temperature control device of the switching zone 2 and the air outlet end of the heating storage tank 32 and Which of the air outlet ends of the heat preservation storage tank 33 is connected; the air outlet end of the temperature control device of the switching zone two is connected to the air inlet end of the heat preservation storage tank 33 and the air inlet end of the waste heat storage tank 34, and a solenoid valve is provided on each of the two connected branches, and the function of the solenoid valve is also to select the connection of the air outlet end of the temperature control device of the switching zone two, the air inlet end of the heat preservation zone is connected to the air outlet end of the heat preservation storage tank 33, the air outlet end of the heat preservation zone is connected to the air inlet end of the preheating storage tank 34, the air inlet end of the switching zone one is connected to the air outlet ends of the heat preservation storage tank 33 and the preheating storage tank 34, and a solenoid valve is provided on each of the two connected branches, the function of the solenoid valve is the same as above, the air outlet end of the switching zone one is connected to the preheating storage tank The air inlet end of the storage tank 34 is connected to the air outlet end of the preheating storage tank 34, and the air outlet end of the preheating zone is connected to the air inlet end of the confluence tank 35. The confluence tank 35 is connected to the flux recovery device 27 through a circulation pipe 36. The heat-insulating storage tank 33 and the preheating storage tank 34 are connected to the flux recovery device through a pressure relief pipe 1 37 and a pressure relief pipe 2 38 respectively. A pressure relief valve is provided on each of the pressure relief pipe 1 37 and the pressure relief pipe 2 38. The pressure relief valve can directly send the excess gas in the heat-insulating storage tank 33 and the preheating storage tank 34 into the flux recovery device for cooling and recovery.The above-mentioned cooling diversion tank 30, nitrogen storage tank 31, heating storage tank 32, insulation storage tank 33, preheating storage tank 34, and confluence tank 35 are all tank structures, and all include an air inlet end (connector) and an air outlet end (air outlet connector). In the entire heat circulation system, the circulating gas and the nitrogen in the nitrogen storage tank enter the heating storage tank 32 and are mixed, and then transported to the temperature control device in the reflow zone for heating, and then discharged to heat and reflow the circuit board. After heating, the high-temperature gas with flux fume is transported to the insulation storage tank 33 through the temperature control device, and then distributed from the insulation storage tank 33 to the temperature control device in the insulation zone. The temperature control device of the insulation storage tank adjusts the temperature of the gas, and after reaching its working temperature, it is ejected by the temperature control device to heat and heat the circuit board. The gas after insulation and heating is sent to the preheating storage tank through the temperature control device in the insulation zone. The preheating storage tank distributes the gas to the preheating zone at the front end, and the temperature control device in the preheating zone After the gas temperature is adjusted, it is transported to the preheating area to preheat the circuit board. Finally, the gas generated by the preheating passes through the confluence tank 35 and the circulation pipe 36, and enters the flux recovery device 27 to cool the gas and recover the flux. The flux is recycled and reused. The cooled gas is treated and then sent to the cooling diversion tank 30 through the circulation pipe 28. Part of the gas can be discharged through the tail gas discharge port 29. The cooling diversion tank 30 distributes the cooled gas to the cooling device, and the cooling device cools the circuit board after reflow soldering. During the cooling process, the gas temperature rises and is then sent to the heating storage tank 32 for recycling. The gas in the insulation storage tank 33 and the preheating storage tank 34 can be directly sent to the flux recovery device 27 through the pressure relief valve to recover the excess gas. The thermal circulation system makes full use of the temperature difference between each heating zone, and uses it after gradual natural cooling, which fully improves the overall thermal efficiency of the equipment and reduces energy consumption.

[0031] Further, such as Figure 7 As shown, the unloading end of the machine base 1 is provided with a horizontal tensioning mechanism 69 installed in the horizontal slide 12 and an inclined tensioning mechanism 70 installed in the inclined slide 13. The horizontal tensioning mechanism 69 is connected to the lower plate support roller 61 where the lower plate sprocket 60 is located and the unloading plate 14; the structure of the inclined tensioning mechanism 70 is the same as that of the horizontal tensioning mechanism 69, and the inclined tensioning mechanism 70 is connected to both ends of the support roller 61 where the other sprocket is located.

[0032] Further, such as Figure 8As shown, the horizontal tensioning mechanism 69 includes a motor base 62, a conveying motor 63, a connecting block 71, a tensioning structure and a moving block 59 and a tensioning structure on the other side of the base 1. The tensioning structure includes a fixed plate 64, a tensioning spring 65, a positioning plate 66, a tensioning rod 67, a tensioning valve 68 and a connecting block 71. The two ends of the lower plate support roller 61 pass through the horizontal slide 12 and are respectively connected to the moving block 59 and the motor base 62. The conveying motor 63 is installed on the motor base 62. The conveying motor 63 is connected to the lower plate support roller 61 by transmission. The connecting block 71 is fixed to the motor base 62 as a whole. Both sides of the blanking plate 14 pass through the water The smooth groove 12 is respectively connected to the moving block 59 and the connecting block 71. The fixed plate 64 is fixed on the base 1. The tensioning rod 67 passes through the guide hole of the fixed plate 64. One end of the tensioning rod 67 is fixedly connected to the tensioning valve 68, and the other end is connected to the moving block 59 or the connecting block 71. The positioning plate 66 is arranged on the tensioning rod 67. The tensioning rod 67 between the positioning plate 66 and the fixed plate 64 is equipped with a tensioning spring 65 in a compressed state, wherein the tensioning spring 65 increases the initial variable tensioning force, and the tensioning valve 68 is used to stably compensate for the tensioning force changes of the tensioning spring 65, so that the tensioning force of the conveying chain 6 remains stable, thereby improving the stability of the conveying process.

[0033] like Figure 9 As shown, the tensioning valve 68 includes a valve body 72, a valve chamber 73, a piston 74, a one-way valve mechanism and a relief valve mechanism. The piston 74 is installed in the valve chamber 73 of the valve body 72. The piston 74 is connected to the tensioning rod 67. The one-way valve mechanism is installed at the liquid inlet of the tensioning valve 68, and the relief valve mechanism is installed at the liquid outlet of the tensioning valve 68. The one-way valve mechanism includes an inlet valve block 80 and an inlet spring 81 installed in the one-way valve chamber. A liquid inlet joint 79 is installed on the liquid inlet of the one-way valve chamber. The relief valve mechanism includes an adjusting bolt 76, an overflow spring 77 and an overflow valve block 78 installed in the overflow valve chamber. An overflow joint 75 is installed on the liquid outlet of the overflow valve chamber. The tensioning valve 68 is used to maintain the tensioning force on the tensioning rod 67 through the overflow valve structure on the valve body.

[0034] like Figure 2As shown, the upper temperature control device 8 includes a temperature control cover 16, a temperature control chamber 17, a motor 18, a wind wheel 19, a heating tube 20, a rectifier plate 21, a temperature sensor 22, an air inlet chamber 23, an air inlet interface 24, a return chamber 25 and a return interface 26. The air inlet interface 24 is the air inlet end of the above-mentioned temperature control device, and the return interface 26 is the air outlet end of the above-mentioned temperature control device. The temperature control cover 16 is fixedly installed on the machine base 1 or the machine cover 2, and the rectifier plate 21 is fixedly installed on the machine base 1 or the machine cover 2. The motor 18 is installed at one end of the temperature control chamber 17, the motor 18 is installed at the other end of the temperature control cover 16, the wind wheel 19 is installed in the temperature control chamber 17, and the wind wheel 19 is connected to the motor 18 by transmission, the heating tube 20 and the temperature sensor 22 are installed in the temperature control chamber 17 and below the wind wheel 19, the air intake chamber 23 is set in the housing of the temperature control cover 16 installed at one end of the motor 18, and the air intake chamber 23 is connected to the temperature control chamber 17, and the air intake chamber 23 is connected to the temperature control chamber 17 by the air intake interface. The port 24 is connected to the pipeline of the heat circulation system; the reflux chamber 25 is arranged on the side wall of the temperature control cover 16, and the opening of the reflux chamber 25 is arranged on the side facing the circuit board to be processed. The reflux chamber 25 is connected to the pipeline of the heat circulation system through the reflux interface 26; the gas enters the air inlet chamber 23 from the air inlet interface 24, and then enters the temperature control chamber 17. The gas just entering the temperature control chamber 17 is heated by the heating tube 20 under the action of the wind wheel 19 and then blown to the circuit board from the air outlet of the rectifier plate 21 to heat the circuit board. The heated gas enters the reflux chamber 25 under the action of the negative pressure of the reflux chamber 25. The negative pressure of the reflux chamber 25 can be formed by adding a negative pressure fan therein, or it can be a negative pressure device installed at other positions in the heat circulation system. The negative pressure device can be installed at the air inlet end of the heating storage tank 32, the insulation storage tank 33, the preheating storage tank 34, etc. It can be specifically set and installed according to actual needs, with the purpose of enabling the gas in the entire heat circulation system to circulate.

[0035] Furthermore, except that the heating tube 20 is not provided inside the cooling device, the rest of the structure is the same as that of the temperature control device.

[0036] like Figure 5 and Figure 6As shown, the upper plate mechanism 4 includes an upper plate motor 52, an upper plate frame 3, an upper plate conveyor belt 54 and a placement slot 55. The upper plate frame 3 is composed of two parallel plate-shaped upper plate frames 53. Each upper plate frame 53 on both sides is equipped with an upper plate conveyor belt 54 arranged on the same horizontal plane. The two upper plate conveyor belts 54 are arranged on opposite sides of the upper plate frame 54. The upper plate conveyor belt 54 is connected to the upper plate motor 52 installed on one side of the upper plate frame 53. A square placement slot 55 is provided above the feeding end of the upper plate frame 53. Further, the transition mechanism 5 includes a connecting frame 56 and a transition roller 57. The connecting frame 56 is installed between the upper plate frames 53 and the upper plate rails on both sides by bolts. The two ends of the transition roller 57 are installed on the connecting frames 56 on both sides. The two ends of the transition roller 57 are directly larger than the diameter of the middle section, and the upper side sections of the two ends of the transition roller 57 are on the same plane as the belt surface of the upper plate conveyor belt 54.

[0037] like Figure 4 As shown, the flux recovery device 27 includes a recovery device shell 39, an air inlet 40, a condensation chamber 41, a condensation pipe 42, a partition 43, a recovery chamber 44, an air outlet 48, a cooling inlet 49, a cooling outlet 50 and a recovery port 51. The interior of the rotary device shell 39 is divided into an upper condensation chamber 41 and a lower recovery chamber 44 by the partition 43. The upper end portion of the condensation pipe 42 is located in the condensation chamber 41, and the lower end portion extends into the recovery chamber 44. The recovery hole 45 is arranged at the bottom of the portion of the condensation pipe 42 extending into the recovery chamber 44. The recovery port 51 is arranged at the bottom of the recovery chamber 44. The two ends of the condensation pipe 42 are respectively connected to the air inlet 40 and the air outlet 48 arranged on the outside of the recovery device shell 39. The cooling inlet 49 and the cooling outlet 50 are arranged on both sides of the condensation chamber 41. Furthermore, a deoxidizing mechanism is provided on the gas outlet 48 of the flux recovery device 27 , and the deoxidizing mechanism includes an outer cover 46 provided on the outside of the recovery device housing 39 and a deoxidizer 47 filled in the inner cavity of the outer cover 46 .

[0038] This specific embodiment is merely an explanation of the present invention and is not a limitation of the invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A reflow soldering machine, comprising a machine base (1), a machine cover (2), an upper plate mechanism (4), a transition mechanism (5), a conveyor chain (6), a tensioning wheel (7), a conveyor track, a plurality of temperature control devices, a plurality of cooling devices, a heat circulation system and a blanking plate (14), wherein the machine cover (2) is mounted on the machine base (1), the upper plate mechanism (4) is mounted at the feed end of the machine base (1), the transition mechanism (5) is mounted between the machine base (1) and the upper plate mechanism (4), the temperature control device comprises an upper temperature control device (8) and a lower temperature control device (9) symmetrically arranged above and below the conveyor track, the cooling device comprises an upper cooling device (10) and a lower cooling device (11) symmetrically arranged above and below the conveyor track, the plurality of temperature control devices sequentially constitute a preheating zone, a heat preservation zone and a reflow zone, and the plurality of cooling devices constitute a cooling zone, and the machine is characterized in that: One or more temperature control devices between the preheating zone and the insulation zone constitute a switching zone 1, and the temperature control device of the switching zone 1 can be switched between the preheating zone and the insulation zone. One or more temperature control devices between the insulation zone and the reflow zone constitute a switching zone 2, and the temperature control device of the switching zone 2 can be switched between the insulation zone and the reflow zone. The thermal circulation system includes a flux recovery device (27), a circulation outlet pipe (28), an exhaust gas discharge port (29), a cooling diversion tank (30), a nitrogen storage tank (31), a heating storage tank (32), an insulation storage tank (33), a preheating storage tank (34), a confluence tank (35), a circulation inlet pipe (36), a pressure relief pipe 1 (37) and a pressure relief pipe 2 (38). The outlet end of the flux recovery device (27) is connected to the circulation outlet pipe. (28) is connected to the air inlet of the cooling diversion tank (30), the other branch of the circulation outlet pipe (28) is connected to the tail gas exhaust port (29), the tail gas exhaust port (29) is installed with a tail gas exhaust pipe (15), the air outlet of the cooling diversion tank (30) is connected to the air inlet of the cooling device in the cooling zone, the air outlet of the cooling device is connected to the air inlet of the heating storage tank (32), the nitrogen storage tank (31) is connected to the heating storage tank (32), the air inlet of the temperature control device in the reflux zone is connected to the air outlet of the heating storage tank (32), the air outlet of the temperature control device in the reflux zone is connected to the air inlet of the insulation storage tank (33), the air inlet of the temperature control device in the switching zone 2 is connected to the air outlet of the heating storage tank (32) and the outlet of the insulation storage tank (33). The air outlet of the temperature control device of the switching zone 2 is connected to the air inlet of the heat preservation tank (33) and the air inlet of the preheating tank (34), and a solenoid valve is provided on each of the two connected branches. The air inlet of the heat preservation zone is connected to the air outlet of the heat preservation tank (33), and the air outlet of the heat preservation zone is connected to the air inlet of the preheating tank (34). The air inlet of the switching zone 1 is connected to the air outlet of the heat preservation tank (33) and the preheating tank (34), and a solenoid valve is provided on each of the two connected branches. The air outlet of the switching zone 1 is connected to the air inlet of the preheating tank (34) and the confluence tank (35), and a solenoid valve is provided on each of the two connected branches. The air inlet of the preheating zone is connected to the air outlet of the preheating tank (3 4), the air outlet end of the preheating zone is connected to the air inlet end of the confluence tank (35), the confluence tank (35) is connected to the flux recovery device (27) through the circulation inlet pipe (36), the heat preservation storage tank (33) and the preheating storage tank (34) are connected to the flux recovery device through the pressure relief pipe 1 (37) and the pressure relief pipe 2 (38), respectively, and a pressure relief valve is provided on each of the pressure relief pipe 1 (37) and the pressure relief pipe 2 (38); the discharge end of the machine base (1) is provided with a horizontal tensioning mechanism (69) installed in the horizontal slide (12) and an inclined tensioning mechanism (70) installed in the inclined slide (13), and the horizontal tensioning mechanism (69) is connected to the lower plate support roller (61) where the lower plate sprocket (60) is located and the discharge plate (14);The structure of the inclined tensioning mechanism (70) is the same as that of the horizontal tensioning mechanism (69), and the inclined tensioning mechanism (70) is connected to both ends of the support roller (61) where the other sprocket is located.

2. A reflow soldering machine according to claim 1, characterized in that: The horizontal tensioning mechanism (69) includes a motor base (62), a conveying motor (63), a connecting block (71), a tensioning structure, and a moving block (59) and a tensioning structure on the other side of the base (1). The tensioning structure includes a fixed plate (64), a tensioning spring (65), a positioning plate (66), a tensioning rod (67), a tensioning valve (68) and a connecting block (71). The two ends of the lower plate support roller (61) pass through the horizontal slide groove (12) and are respectively connected to the moving block (59) and the motor base (62). The conveying motor (63) is installed on the motor base (62). The conveying motor (63) and the lower plate support roller (61) are driven by the transmission. The connecting block (71) is fixed to the motor base (62) as a whole, and the two sides of the blanking plate (14) pass through the horizontal slide groove (12) and are respectively connected to the moving block (59) and the connecting block (71), and the fixed plate (64) is fixed on the machine base (1), and the tensioning rod (67) passes through the guide hole of the fixed plate (64), and one end of the tensioning rod (67) is fixedly connected to the tensioning valve (68), and the other end is connected to the moving block (59) or the connecting block (71), and the positioning plate (66) is set on the tensioning rod (67), and the tensioning rod (67) between the positioning plate (66) and the fixed plate (64) is provided with a tensioning spring (65) in a compressed state.

3. The reflow soldering machine according to claim 2, wherein: The tensioning valve (68) comprises a valve body (72), a valve chamber (73), a piston (74), a one-way valve mechanism and a relief valve mechanism. The piston (74) is installed in the valve chamber (73) of the valve body (72). The piston (74) is connected to the tensioning rod (67). The one-way valve mechanism is installed at the liquid inlet of the tensioning valve (68). The relief valve mechanism is installed at the liquid outlet of the tensioning valve (68). The one-way valve mechanism comprises a liquid inlet valve block (80) and a liquid inlet spring (81) installed in the one-way valve chamber. A liquid inlet joint (79) is installed on the liquid inlet of the one-way valve chamber. The relief valve mechanism comprises an adjusting bolt (76) installed in the relief valve chamber, an relief spring (77) and a relief valve block (78). An relief joint (75) is installed on the liquid outlet of the relief valve chamber.

4. The reflow soldering machine according to claim 3, wherein: The upper temperature control device (8) includes a temperature control cover (16), a temperature control chamber (17), a motor (18), a wind wheel (19), a heating tube (20), a rectifier plate (21), a temperature sensor (22), an air inlet chamber (23), an air inlet interface (24), a return chamber (25) and a return interface (26), wherein the temperature control cover (16) is fixedly mounted on the machine base (1) or the machine cover (2), the rectifier plate (21) is mounted on one end of the opening of the temperature control chamber (17), the motor (18) is mounted on the other end of the temperature control cover (16), the wind wheel (19) is mounted in the temperature control chamber (17), and the wind wheel (19) and the motor (18) are connected to each other. ) transmission connection, the heating tube (20) and the temperature sensor (22) are installed in the temperature control chamber (17) and below the wind wheel (19), the air inlet chamber (23) is arranged in the shell of the temperature control cover (16) installed at one end of the motor (18), and the air inlet chamber (23) is connected to the temperature control chamber (17), and the air inlet chamber (23) is connected to the pipeline of the heat circulation system through the air inlet interface (24); the reflux chamber (25) is arranged on the side wall of the temperature control cover (16), and the opening of the reflux chamber (25) is arranged on the side facing the circuit board to be processed, and the reflux chamber (25) is connected to the pipeline of the heat circulation system through the reflux interface (26).

5. The reflow soldering machine according to claim 4, characterized in that: The cooling device has the same structure as the temperature control device, except that no heating tube (20) is provided inside.

6. The reflow soldering machine according to claim 5, characterized in that: The upper plate mechanism (4) includes an upper plate motor (52), an upper plate frame (3), an upper plate conveyor belt (54) and a placement groove (55). The upper plate frame (3) is composed of two parallel plate-shaped upper plate frames (53). An upper plate conveyor belt (54) arranged on the same horizontal plane is installed on each of the upper plate frames (53) on both sides. The opposite sides of the two upper plate conveyor belts (54) protrude from the outer edge of the upper plate frame (53). The upper plate conveyor belt (54) is connected to the upper plate motor (52) installed on one side of the upper plate frame (53) in a transmission manner. A square placement groove (55) is opened above the feeding end of the upper plate frame (53).

7. The reflow soldering machine according to claim 6, characterized in that: The transition mechanism (5) includes a connecting frame (56) and a transition roller (57), wherein the connecting frame (56) is installed between the upper plate frame (53) and the upper plate track on both sides by bolts, and both ends of the transition roller (57) are installed on the connecting frames (56) on both sides, and the diameter of the two ends of the transition roller (57) is larger than the diameter of the middle section, and the upper side sections of the two ends of the transition roller (57) are on the same plane as the belt surface of the upper plate conveyor belt (54).

8. The reflow soldering machine according to claim 7, characterized in that: The solder flux recovery device (27) comprises a recovery device shell (39), an air inlet (40), a condensation chamber (41), a condensation pipe (42), a partition (43), a recovery chamber (44), an air outlet (48), a cooling inlet (49), a cooling outlet (50) and a recovery port (51). The interior of the recovery device shell (39) is divided into an upper condensation chamber (41) and a lower recovery chamber (44) by the partition (43). The upper end of the condensation pipe (42) is located at the cooling chamber. The lower end portion of the condensation chamber (41) extends into the recovery chamber (44), the recovery hole (45) is arranged at the bottom of the portion of the condensation tube (42) extending into the recovery chamber (44), the recovery port (51) is arranged at the bottom of the recovery chamber (44), the two ends of the condensation tube (42) are respectively connected to the air inlet (40) and the air outlet (48) arranged on the outside of the recovery device shell (39), and the cooling inlet (49) and the cooling outlet (50) are arranged on both sides of the condensation chamber (41).

9. The reflow soldering machine according to claim 8, characterized in that: A deoxidizing mechanism is provided on the air outlet (48) of the flux recovery device (27), and the deoxidizing mechanism comprises an outer cover (46) arranged outside the recovery device shell (39) and a deoxidizer (47) filled in the inner cavity of the outer cover (46).

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