reflow oven

Abstract

The present application discloses a reflow soldering furnace. The reflow soldering furnace includes a heating zone, a cooling zone, a barrier exhaust zone, an exhaust channel, an exhaust power device and a detection device. The heating zone includes a heating zone inlet and a heating zone outlet. The cooling zone includes a cooling zone inlet and a cooling zone outlet. The barrier exhaust zone is located between the heating zone outlet and the cooling zone inlet. The inlet of the exhaust channel is connected to the barrier exhaust zone. The exhaust power device is arranged on the exhaust channel. The detection device is arranged on the exhaust channel and is used to detect the parameters of the gas in the exhaust channel, and the parameters of the gas reflect the blockage condition of the exhaust power device. The reflow soldering furnace of the present application can ensure that the gas containing flux is sufficiently extracted in the barrier exhaust zone, thereby ensuring the production quality of the circuit board and improving the qualified rate of the circuit board.

Description

Technical Field

[0001] The present application relates to the field of welding, and in particular to a reflow oven. Background Art

[0002] A reflow oven is used to solder components onto circuit boards. Specifically, it has a heating zone and a cooling zone. The heating zone heats the circuit board, melting the solder paste (e.g., tin paste) onto the board into a liquid state. The cooling zone solidifies the liquid solder paste into a solid state, solidifying it in selected areas on the circuit board to solder the electronic components to the board. Summary of the Invention

[0003] Exemplary embodiments of the present application can solve at least some of the above-mentioned problems. For example, the present application provides a reflow soldering furnace. The reflow soldering furnace includes a heating zone, a cooling zone, a barrier exhaust zone, an exhaust channel, an exhaust power device and a detection device. The heating zone includes a heating zone inlet and a heating zone outlet. The cooling zone includes a cooling zone inlet and a cooling zone outlet. The barrier exhaust zone is located between the heating zone outlet and the cooling zone inlet. The inlet of the exhaust channel is connected to the barrier exhaust zone. The exhaust power device is arranged on the exhaust channel. The detection device is arranged on the exhaust channel for detecting the parameters of the gas in the exhaust channel, and the parameters of the gas reflect the blockage condition of the exhaust power device.

[0004] According to the reflow soldering furnace of the present application, the reflow soldering furnace further includes a control device. The control device is communicatively connected to the detection device. The detection device is configured to send a detection signal to the control device, and the control device is configured to receive the detection signal sent by the detection device.

[0005] According to the reflow oven of the present application, the control device is communicatively connected with the exhaust power device, and the control device is configured to control the opening and closing of the exhaust power device.

[0006] According to the reflow soldering furnace of the present application, the reflow soldering furnace further includes an audible or visual alarm device. The audible or visual alarm device is communicatively connected to the control device, and the control device is configured to control the audible or visual alarm device to emit an audible or visual message based on the detection signal received from the detection device.

[0007] According to the reflow soldering furnace of the present application, the reflow soldering furnace further comprises a heating device, wherein the heating device is configured to heat the exhaust power device.

[0008] According to the reflow oven of the present application, the control device is communicatively connected to the heating device, and the control device is configured to control the turning on and off of the heating device according to the detection signal provided by the detection device.

[0009] According to the reflow oven of the present application, the heating device includes an electric heating wire, and the electric heating wire is arranged around the exhaust power device.

[0010] According to the reflow oven of the present application, the detection device includes a flow detection device for detecting the flow of the gas in the exhaust channel.

[0011] According to the reflow oven of the present application, the detection device includes a pressure detection device for detecting the pressure of the gas in the exhaust channel.

[0012] According to the reflow oven of the present application, the exhaust power device includes a vacuum generator, a fan or a pump.

[0013] The reflow oven of the present application can ensure that the gas containing flux is sufficiently extracted in the barrier exhaust zone, thereby ensuring the production quality of the circuit board and improving the qualified rate of the circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] These and other features and advantages of the present application may be better understood by reading the following detailed description with reference to the accompanying drawings, in which like reference numerals refer to like parts throughout, wherein:

[0015] Figure 1 is a simplified system diagram of a reflow oven according to one embodiment of the present application;

[0016] Figure 2 yes Figure 1 A simplified schematic diagram of an embodiment of a control device;

[0017] Figure 3 The control device is Figure 1 Schematic diagram of the control flow of the heating device of the reflow oven shown;

[0018] Figure 4A A three-dimensional diagram of a pipe wall of a conventional exhaust power device without a heating device;

[0019] Figure 4B for Figure 4A The exhaust power device shown has a pipe wall along Figure 4A Section view along section line AA;

[0020] Figure 5A A three-dimensional diagram of a pipe wall of the exhaust power device of the present application provided with a heating device;

[0021] Figure 5B for Figure 5A The exhaust power device shown has a pipe wall along Figure 5A Section view along section line BB;

[0022] Figure 6 is a simplified system diagram of a reflow oven according to another embodiment of the present application. DETAILED DESCRIPTION

[0023] The various embodiments of the present application will be described below with reference to the accompanying drawings which form a part of this specification. In the following drawings, the same parts use the same figure numbers, and similar parts use similar figure numbers.

[0024] Figure 1 FIG. 1 is a simplified system diagram of a reflow oven 1 according to an embodiment of the present application. Figure 1 As shown, the reflow oven 1 includes a heating zone 10, a barrier exhaust zone 16, and a cooling zone 18. The heating zone 10 includes a heating zone inlet 151 and a heating zone outlet 152. The barrier exhaust zone 16 includes a barrier exhaust zone inlet 153 and a barrier exhaust zone outlet 154. The cooling zone 18 includes a cooling zone inlet 155 and a cooling zone outlet 156. The barrier exhaust zone 16 is disposed between the heating zone 10 and the cooling zone 18. More specifically, the barrier exhaust zone 16 is disposed between the heating zone outlet 152 and the cooling zone inlet 155. The barrier exhaust zone inlet 153 communicates with the heating zone outlet 152, and the barrier exhaust zone outlet 154 communicates with the cooling zone inlet 155. The barrier exhaust zone 16 includes a barrier exhaust zone exhaust outlet 159 for allowing gas in the reflow oven 1 to exhaust the reflow oven 1, thereby preventing heat from the heating zone 10 from being transferred to the cooling zone 18.

[0025] The reflow oven 1 also includes a furnace chamber and a conveyor assembly (not shown). The furnace chamber is disposed transversely through the heating zone 10, the barrier exhaust zone 16, and the cooling zone 18, thereby providing fluid communication between the heating zone 10, the barrier exhaust zone 16, and the cooling zone 18. The conveyor assembly is disposed within the furnace chamber and also transversely through the heating zone 10, the barrier exhaust zone 16, and the cooling zone 18. The conveyor assembly is used to carry circuit boards, allowing them to enter the reflow oven 1 through the heating zone entrance 151, pass through the heating zone 10, the barrier exhaust zone 16, and the cooling zone 18, and then exit the reflow oven 1 through the cooling zone exit 156.

[0026] Specifically, the heating zone 10 and the cooling zone 18 may each include a plurality of sub-areas. Figure 1In the illustrated embodiment, the heating zone 10 includes ten sub-zones. These ten sub-zones include a relatively cool zone 12 and a relatively hot zone 14. The temperature of the relatively hot zone 14 is higher than that of the relatively cool zone 12. The relatively cool zone 12 includes two preheating zones 17. The relatively hot zone 14 includes four uniform temperature zones 13 and four peak temperature zones 15. The preheating zones 17, the uniform temperature zones 13, and the peak temperature zones 15 are arranged adjacent to each other. The heating zone 10 is used to provide a higher temperature to the circuit board than room temperature. The cooling zone 18 includes four cooling sub-zones 11. The cooling zone 18 is used to provide a lower temperature to the circuit board than that of the heating zone 10.

[0027] After the circuit board enters the reflow soldering furnace 1 through the heating zone entrance 151, the circuit board can be gradually heated in the preheating zone 17 and the uniform temperature zone 13. At least a portion of the flux in the solder paste on the circuit board will vaporize. In the peak zone 15, the circuit board continues to be heated and the solder paste melts. Next, the circuit board passes through the barrier exhaust zone 16. In the barrier exhaust zone 16, the high-temperature gas escaping from the heating zone outlet 152 is discharged through the barrier exhaust zone exhaust outlet 159, so that the cooling zone 18 can maintain a lower temperature without being affected by the high-temperature gas escaping from the heating zone outlet 152. After passing through the barrier exhaust zone 16, the circuit board is conveyed into the cooling zone 18. In the four cooling sub-zones 11, the solder paste is cooled and solidified on the welding area of the circuit board, thereby connecting the electronic components to the circuit board.

[0028] The reflow oven 1 further includes an exhaust duct 115 and an exhaust power unit 102. The exhaust duct 115 includes an exhaust duct inlet 161 and an exhaust duct outlet 162. The exhaust duct inlet 161 is connected to the barrier exhaust zone exhaust outlet 159, thereby connecting the exhaust duct 115 to the barrier exhaust zone 16. The exhaust power unit 102 is disposed on the exhaust duct 115 and is used to provide power to draw gas out of the barrier exhaust zone 16. As an example, the exhaust power unit 102 may be a vacuum generator, a pump, or a blower.

[0029] More specifically, exhaust channel 115 includes a first exhaust channel 171 and a second exhaust channel 172. The inlet of first exhaust channel 171 is exhaust channel inlet 161 of exhaust channel 115, which is connected to barrier exhaust zone exhaust outlet 159. The outlet of first exhaust channel 171 is connected to the inlet of exhaust power device 102. The inlet of second exhaust channel 172 is connected to the outlet of exhaust power device 102. The outlet of second exhaust channel 172 is exhaust channel outlet 162 of exhaust channel 115.

[0030] The reflow oven 1 further includes a control device 120. The control device 120 is in communication with the exhaust power device 102. The control device 120 can control the exhaust power device 102 to be turned on and off.

[0031] The reflow oven 1 also includes a detection device 111. The detection device 111 is arranged on the exhaust channel 115, and is used to detect the parameters of the gas in the exhaust channel 115, and the parameters of the gas can reflect the blockage condition of the exhaust power device 102. In an embodiment of the present application, the detection device 111 is arranged on the first exhaust channel 171. The detection device 111 is a pressure difference detection device, which is used to detect the difference between the pressure of the gas in the exhaust channel 115 and the atmospheric pressure at the position where the pressure difference detection device is located. The control device 120 is communicatively connected to the detection device 111. The detection device 111 is capable of providing a detection signal to the control device 120. The control device 120 is configured to be able to receive the detection signal emitted by the detection device 111.

[0032] The reflow oven 1 also includes a heating device 132. The heating device 132 is arranged to heat the exhaust power device 102. The control device 120 is communicatively connected to the heating device 132. The control device 120 can receive a detection signal provided by the detection device 111 and control the opening and closing of the heating device 132 based on the detection signal. As an example, the heating device 132 can include an electric heating wire 133, which is arranged around the exhaust power device 102. When the electric heating wire 133 is energized, the electrical energy can be converted into thermal energy, thereby heating the exhaust power device 102 and the gas flowing through the exhaust power device 102.

[0033] Through long-term observation, the inventors discovered that after a reflow oven has been running for an extended period, residue remains on the soldered circuit boards exiting the cooling zone. Analysis revealed that this residue is liquid flux or solid rosin contained in the flux. The presence of this residue can reduce the quality of the circuit boards. The amount of this residue increases after the reflow oven has been running for extended periods, even reducing the yield rate of the circuit boards. A comprehensive analysis of the overall operation of the reflow oven revealed that this residue also occurs on the inner wall of the furnace chamber in the cooling zone (i.e., the inner side of the furnace shell), with a higher concentration on the inner wall of the furnace chamber in the cooling zone, near the barrier exhaust zone. This accumulated residue can drip onto the circuit boards, leaving residue on them. The inventors further analyzed and determined that this is caused by a blockage in the exhaust power unit. Specifically, the temperature in the heating zone is high, typically reaching 280°C. Because the first exhaust duct is fluidically connected to the barrier exhaust zone, it is typically coated with thermal insulation material. However, the exhaust power unit is often exposed to ambient air. The temperature difference between the ambient air and the temperature in the heating zone can reach 100°C. When the flux gas is extracted from the furnace and contacts the exhaust power unit, the temperature drops rapidly, causing the flux gas to condense into solid flux and adhere to the inner wall of the exhaust power unit. Over time, the flow area of the exhaust power unit decreases due to the adhesion of the flux solid. This affects the exhaust efficiency of the exhaust zone, causing the flux gas generated in the heating zone and unable to be sufficiently extracted from the furnace by the exhaust power unit to enter the cooling zone, preferentially entering the cooling zone near the heating zone. After the temperature of the flux gas gradually decreases in the cooling zone, it solidifies into a solid and adheres to the walls of the cooling zone. Some of it condenses on the circuit boards passing through the cooling zone, thereby reducing the processing quality of the circuit boards.

[0034] The heating device 132 in the reflow oven 1 of the present application can heat the exhaust power device 102, thereby causing the solidified flux inside the exhaust power device 102 to heat up again and become gas. When the heating device 132 is turned on, the exhaust power device 102 also remains turned on, allowing the flux gas to be discharged from the exhaust power device 102. The exhaust power device 102 in the reflow oven 1 of the present application can extract a sufficient amount of flux gas from the furnace, effectively preventing the flux gas from condensing into solid flux and preventing the flux gas from entering the cooling zone 18, thereby ensuring the production quality of the circuit board and significantly improving the qualified rate of the circuit board.

[0035] Figure 2 yes Figure 1 A simplified schematic diagram of an embodiment of the control device 120 is shown in FIG. Figure 2As shown, the control device 120 includes a bus 202, a processor 204, an input interface 206, an output interface 208, and a memory 214 having a control program 216. Each component of the control device 120, including the processor 204, the input interface 206, the output interface 208, and the memory 214, is communicatively connected to the bus 202, so that the processor 204 can control the operation of the input interface 206, the output interface 208, and the memory 214. Specifically, the memory 214 is used to store programs, instructions, and data, and the processor 204 reads programs, instructions, and data from the memory 214 and can write data to the memory 214.

[0036] Input interface 206 receives external signals and data via connection 218, including detection signals and data from detection device 111. Output interface 208 sends external control signals via connection 222, including on / off control signals to heating device 132 and exhaust power unit 102. The memory 214 of control device 120 stores control programs and data such as pre-set target settings. Various parameters can be pre-set during the manufacturing process or manually input or imported at the time of use.

[0037] Figure 3 The control device 120 is Figure 1 The control flow diagram of the heating device 132 of the reflow oven 1 is shown. Figure 3 The program of the flow chart shown in FIG is stored in the memory 214 of the control device 120. The control process can control the opening and closing of the heating device 132 according to the detection signal sent by the detection device 111.

[0038] like Figure 3 As shown, in step 301, processor 204 detects whether exhaust power device 102 is currently operating. In other words, processor 204 detects whether exhaust power device 102 has been activated. If exhaust power device 102 is not currently operating, processor 204 proceeds to step 301. If exhaust power device 102 is currently operating, processor 204 proceeds to step 303.

[0039] In step 303 , the processor 204 obtains the current pressure difference value from the detection device 111 . The processor 204 then proceeds to step 304 .

[0040] In step 304, processor 204 determines whether the current pressure differential value is lower than the first set pressure differential value. If the current pressure differential value is not lower than the first set pressure differential value (i.e., the current pressure differential value is higher than or equal to the first set pressure differential value), processor 204 proceeds to step 303. If the current pressure differential value is lower than the first set pressure differential value, processor 204 proceeds to step 306.

[0041] In step 306 , the processor 204 turns on the heating device 132 . The processor 204 then moves the operation to step 308 .

[0042] In step 308 , the processor 204 obtains the current pressure difference value from the detection device 111 . The processor 204 then proceeds to step 310 .

[0043] In step 310, the processor 204 determines whether the current pressure differential value is higher than the second set pressure differential value. If the current pressure differential value is not higher than the second set pressure differential value (i.e., the current pressure differential value is lower than or equal to the second set pressure differential value), the processor 204 proceeds to step 309. If the current pressure differential value is higher than the second set pressure differential value, the processor 204 proceeds to step 312.

[0044] In step 312, the processor 204 turns off the heating device 132. The processor 204 then ends the control process.

[0045] It should be noted that in Figure 3 In the illustrated embodiment, the exhaust power device 102 is also operated while the heating device 132 is in operation. This is because, generally, when the exhaust power device 102 is in operation, the flux gas will flow through the exhaust power device 102 and solidify on the exhaust power device 102. However, those skilled in the art will appreciate that the heating device 132 may also be turned on when the exhaust power device 102 is not in operation to remove the flux solids adhering to the exhaust power device 102.

[0046] As an example, the first set pressure difference value can be 80Pa, and the second set pressure value can be 180Pa. When the current pressure difference value is lower than the first set pressure difference value of 80Pa, it means that the exhaust power device 102 cannot provide sufficient suction capacity. At this time, it is necessary to turn on the heating device 132 to heat the flux solids in the exhaust power device 102 to turn them into flux gas. As the flux solids are heated and turned into flux gas, the flux solids attached to the exhaust power device 102 gradually decrease, the airflow flow area of the exhaust power device 102 increases, and the current pressure difference value also increases. When the current pressure difference value is higher than the second set pressure value of 180Pa, it means that the exhaust power device 102 can provide at least 180Pa of suction capacity. At this time, the exhaust power device 102 can provide sufficient suction capacity, and the heating device 132 can be turned off.

[0047] It should be noted that although 80 Pa is set as the first set pressure differential value and 180 Pa is set as the second set pressure value in this application, those skilled in the art will understand that the first set pressure differential value and the second set pressure value can be set specifically according to the operating conditions of the reflow oven 1. In addition, the first set pressure differential value can be different from the second set pressure value, or the first set pressure differential value can be equal to the second set pressure value (i.e., the first set pressure differential value is equal to the second set pressure value).

[0048] It should also be noted that, although the detection device 111 in the embodiment of the present application is a pressure differential detection device (e.g., a pressure differential sensor), those skilled in the art will appreciate that the detection device 111 may also be a pressure detection device (e.g., a pressure sensor) for detecting the pressure of the gas in the exhaust passage 115. Those skilled in the art will also appreciate that the detection device 111 may also be a flow detection device (e.g., a flow sensor) for detecting the flow of gas in the exhaust passage 115. The blockage condition in the exhaust power device 102 is determined based on the flow value of the gas in the exhaust passage 115, thereby setting a first set flow value and a second set flow value (the first set flow value may be equal to the second set flow value) to control the opening and closing of the heating device 132.

[0049] Figure 4A This is a three-dimensional diagram of the pipe wall of a traditional exhaust power device without a heating device. Figure 4B for Figure 4A The exhaust power device shown has a pipe wall along Figure 4A The cross-section view along the middle section line AA. The dotted shadows represent the flux solids attached to the wall. Figures 4A-4B As can be seen in the figure, the flow area of the exhaust power device will be reduced by nearly 70%. This will greatly reduce the speed of flux gas discharged from the furnace and reduce the qualified rate of circuit boards.

[0050] Figure 5A This is a three-dimensional diagram of the pipe wall of the exhaust power device of the present application provided with a heating device. Figure 5B for Figure 5A The exhaust power device shown has a pipe wall along Figure 5A The cross-section view along the middle section line BB. The dotted shadows represent the flux solids attached to the wall. Figures 5A-5B It can be seen that there is almost no flux solid attached to the wall of the exhaust power device, which can ensure that the actual flow area of the exhaust power device is consistent with its designed flow area, thereby ensuring the speed at which the flux gas is discharged from the furnace and greatly improving the qualified rate of the circuit board.

[0051] Figure 6FIG. 4 is a simplified system diagram of a reflow oven 6 according to another embodiment of the present application. Figure 6 Reflow oven 6 with Figure 1 The same parts of the reflow oven 1 are not described here. Figure 1 The differences of the reflow oven 1 are: Figure 6 The reflow oven 6 includes an auditory or visual alarm device 611, but does not include a heating device for heating the exhaust power device 102. The auditory or visual alarm device 611 is communicatively connected to the control device 120. The control device 120 is configured to control the auditory or visual alarm device 611 to emit auditory or visual information based on the detection signal received from the detection device 111. Specifically, when the control device 120 receives a gas parameter from the detection device 111 and determines that the gas parameter reflects that the exhaust power device 102 is blocked, the control device 120 will send a signal to the auditory or visual alarm device 611. The auditory or visual alarm device 611 is capable of emitting auditory or visual information to alarm the operator. As an example, the auditory or visual alarm device 611 includes a chirping device, a warning device or a display device. When the operator sees the alarm issued by the auditory or visual alarm device 611, the exhaust power device 102 can be removed and replaced with a new exhaust power device, thereby ensuring the actual flow area of the exhaust power device to ensure the speed at which the flux gas is discharged from the furnace and greatly improve the qualified rate of the circuit board.

[0052] Although only some features of the present application have been illustrated and described herein, various modifications and variations may be made by those skilled in the art. It should be understood that the appended claims are intended to cover all such modifications and variations that fall within the spirit and scope of the present application.

Claims

1. A reflow oven, characterized in that: The reflow oven comprises: a heating zone, the heating zone comprising a heating zone inlet and a heating zone outlet; a cooling zone, the cooling zone comprising a cooling zone inlet and a cooling zone outlet; a barrier exhaust zone, the barrier exhaust zone being located between the outlet of the heating zone and the inlet of the cooling zone; an exhaust channel, wherein an inlet of the exhaust channel is connected to the barrier exhaust area; an exhaust power device, the exhaust power device being arranged on the exhaust passage; a detection device, the detection device being disposed on the exhaust passage and configured to detect parameters of the gas in the exhaust passage, wherein the parameters of the gas reflect a blockage condition of the exhaust power device; and A heating device is configured to heat the exhaust power device in response to a parameter of the gas reflecting a blockage condition of the exhaust power device, so that the flux solid causing the blockage of the exhaust power device is heated to flux gas and then discharged.

2. The reflow oven according to claim 1, wherein Also includes: a control device, the control device being communicatively connected to the detection device; The detection device is configured to send a detection signal to the control device, and the control device is configured to be able to receive the detection signal sent by the detection device.

3. The reflow oven according to claim 2, wherein: The control device is in communication with the exhaust power device, and is configured to control the opening and closing of the exhaust power device.

4. The reflow oven according to claim 2, wherein Also includes: An auditory or visual alarm device is communicatively connected to the control device, and the control device is configured to control the auditory or visual alarm device to emit auditory or visual information according to the detection signal received from the detection device.

5. The reflow oven according to claim 2, wherein: The control device is communicatively connected to the heating device, and the control device is configured to control the turning on and off of the heating device according to the detection signal provided by the detection device; Wherein, when the control device detects that the exhaust power device is running, the control device turns on the heating device.

6. The reflow oven according to claim 1, wherein: The heating device includes an electric heating wire, and the electric heating wire is arranged around the exhaust power device.

7. The reflow oven according to claim 1, wherein: The detection device includes a flow detection device for detecting the flow of gas in the exhaust channel.

8. The reflow oven according to claim 1, wherein: The detection device includes a pressure detection device for detecting the pressure of the gas in the exhaust channel.

9. The reflow oven according to claim 1, wherein: The exhaust power device includes a vacuum generator, a fan or a pump.

10. The reflow oven according to claim 1, wherein: The exhaust channel includes a first exhaust channel and a second exhaust channel, the exhaust power device is located between the first exhaust channel and the second exhaust channel, and the detection device is arranged on the first exhaust channel.

11. The reflow oven according to claim 2, wherein: The control device includes a processor, and the control process of the heating device by the control device includes: When the processor detects that the exhaust power device has been started, the processor obtains a current pressure difference value from the detection device; When the processor determines that the current pressure difference value is lower than a first set pressure difference value, the processor turns on the heating device.

12. A reflow oven, characterized in that: The reflow oven comprises: a heating zone, the heating zone comprising a heating zone inlet and a heating zone outlet; a cooling zone, the cooling zone comprising a cooling zone inlet and a cooling zone outlet; a barrier exhaust zone, the barrier exhaust zone being located between the outlet of the heating zone and the inlet of the cooling zone; an exhaust channel, wherein an inlet of the exhaust channel is connected to the barrier exhaust area; an exhaust power device, the exhaust power device being arranged on the exhaust passage; Heating device; and a detection device, which is arranged on the exhaust passage and is used to detect the pressure of the gas in the exhaust passage, wherein when the pressure of the gas is lower than a threshold value reflecting the blockage condition of the exhaust power device, the heating device is turned on to heat the exhaust power device, so that the flux solid causing the blockage of the exhaust power device is heated to flux gas and then discharged, and when the pressure of the gas is higher than the threshold value, the heating device is turned off.

Images