WO2023115000A1

WO2023115000A1 - Reflow oven

Info

Publication number: WO2023115000A1
Application number: PCT/US2022/081804
Authority: WO
Inventors: Yuwei Wang; Yuexin CHEN; De Wei
Original assignee: Illinois Tool Works Inc.
Priority date: 2021-12-16
Filing date: 2022-12-16
Publication date: 2023-06-22
Also published as: CN116265162A; TW202342206A

Abstract

The present application discloses a reflow oven comprising: a furnace chamber, a plurality of heating units, and a delivery channel, wherein an upper suction channel, the upper exhaust channel, the lower suction channel, and the lower exhaust channel are configured such that gas discharged from the upper fan 5 exhaust port flows through the upper exhaust channel to a middle region of a delivery channel sub-region, then is sucked by the lower suction channel and delivered to the lower fan suction port, and the gas discharged from the lower fan exhaust port sequentially flows through the lower exhaust channel, the side regions of the delivery channel sub-region and the upper suction channel, and is then 10 received by the upper fan suction port. In the reflow oven of the present application, by changing the flow direction of the exhaust channel and the suction channel of the heating unit lower portion, the circuit board is simultaneously subjected to downward pressure and suction while flowing through the delivery channel sub-region so as to prevent warping and deformation of the circuit board, which greatly improves the 15 soldering yield of the circuit board and is particularly beneficial for soldering of the sheet circuit board.

Description

REFLOW OVEN

Technical Field

The present application relates to a reflow oven, and in particular to a reflow oven for sheet soldering.

Background

In the production of printed circuit boards, electronic components are typically mounted to circuit boards using a process called “reflow soldering.” In a typical reflow soldering process, a solder paste (e.g., tin paste) is deposited into a selected area on a circuit board and a wire of one or more electronic components is inserted into the deposited solder paste. The circuit board then passes through a reflow oven in which the solder paste refluxes (i.e. , is heated to a melting or reflux temperature) in a heating area and then cools in a cooling area to electrically and mechanically connect the wires of the electronic components to the circuit board. As used herein, the term “circuit board” comprises a substrate assembly of any type of electronic element, such as comprises a wafer substrate.

During the soldering process, warping of the circuit board may occur when the circuit board is heated, which makes the soldering fail to meet the requirements and affects the product yield. Especially for sheet circuit boards with thin thicknesses (e.g., 0.13 to 0.5 mm in thickness), they are more flexible and more susceptible to warping.

Summary

At least one object of the present application is to provide a reflow oven comprising: a furnace chamber; a plurality of heating units disposed side by side in the furnace chamber along a first direction, each of the heating units comprises a heating unit upper portion and a heating unit lower portion; a delivery channel extending through the plurality of heating units along the first direction and comprises a plurality of delivery channel sub-regions respectively located between the heating unit upper portion and the heating unit lower portion of each heating unit, the delivery channel sub-regions comprises in a second direction perpendicular to the first direction a middle region for passing a processing element through and side regions on opposite sides of the middle region; wherein the heating unit upper portion includes an upper fan, an upper suction channel and an upper exhaust channel, the upper fan having an upper fan suction port and an upper fan exhaust port; the heating unit lower portion includes a lower fan, a lower suction channel and a lower exhaust channel, the lower fan having a lower fan suction port and a lower fan exhaust port; wherein the upper suction channel, the upper exhaust channel, the lower suction channel and the lower exhaust channel are configured such that gas discharged from the upper fan exhaust port flows through the upper exhaust channel and blows to the middle region of the delivery channel sub-region, then is sucked by the lower suction channel and delivered to the lower fan suction port, and the gas discharged from the lower fan exhaust port sequentially flows through the lower exhaust channel, the side regions of the delivery channel sub-region and the upper suction channel, and is then received by the upper fan suction port.

According to the above, the heating unit upper portion and the heating unit lower portion of each heating unit and the delivery channel sub-region located between the heating unit upper portion and the heating unit lower portion collectively form a heated gas internal circulation passage; wherein the heated gas internal circulation passage includes a forward passage for heated gas to flow from top to bottom and a backward passage for the heated gas to flow from bottom to top, wherein the forward passage includes the upper exhaust channel, the middle region of the delivery channel sub-region and the lower suction channel, and the backward passage includes the lower exhaust channel, the side regions of the delivery channel sub-region and the upper suction channel.

According to the above, the heating unit upper portion includes an upper housing and an upper divider disposed within the upper housing, the upper fan suction port and the upper fan exhaust port are disposed within the upper housing, the upper suction channel and the upper exhaust channel are formed by the upper divider and the upper housing, the outlet of the upper exhaust channel is located directly above the middle region of the delivery channel sub-region; the heating unit lower portion includes a lower housing and a lower divider disposed within the lower housing, and the lower fan suction port and the lower fan exhaust port are disposed within the lower housing, the lower suction channel and the lower exhaust channel are formed by the lower divider and the lower housing, the inlet of the lower suction channel is located directly below the middle region of the delivery channel subregion.

According to the above, the lower fan suction port is located directly below the middle region of the delivery channel sub-region, and there is no lower divider between the lower fan suction port and the middle region of the delivery channel sub-region.

According to the above, the lower housing of the heating unit lower portion includes a pair of first direction lower side walls extending in the first direction, a pair of second direction lower side walls extending in a second direction, and a lower bottom wall, the first direction lower side walls, the second direction lower side walls and the lower bottom wall being connected to each other such that the lower housing forms a box body shape with a top opening, the lower bottom wall having a fan receiving port; the lower divider includes a transverse partition and a pair of vertical partitions located above the transverse partitions and connected to both ends of the transverse partition in the second direction, the transverse partition having a lower fan opening; wherein the transverse partition and the pair of vertical partitions are all connected to the pair of second direction lower side walls to collectively form the lower suction channel through the transverse partition, the pair of vertical partitions and the pair of second direction lower side walls, the lower fan opening forming an outlet of the lower suction channel; wherein the transverse partition is spaced from the lower bottom wall by a certain distance to form a part of the lower exhaust channel, and the pair of vertical partitions are spaced from the pair of first direction lower side walls by a certain distance, respectively, to form another part of the lower exhaust channel.

According to the above, the lower fan suction port is connected to a lower fan opening of the transverse partition, and the lower fan exhaust port is disposed between the transverse partition and the lower bottom wall and in communication with the lower exhaust channel.

According to the above, the lower housing includes a housing insertion port disposed on one of the pair of first direction lower side walls; the lower divider further includes a pair of heating element insertion ports disposed on the pair of vertical partitions, respectively; the lower divider further includes a pair of spacer rings disposed around the pair of heating element insertion ports respectively and between the pair of vertical partitions and the first direction lower side walls to isolate the lower suction channel and the lower exhaust channel while being able to receive a heating element.

According to the above, the upper housing of the heating unit upper portion includes a pair of first direction side walls extending in the first direction, a pair of second direction side walls extending in the second direction, and an upper top wall, the first direction upper side walls, the second direction upper side walls and the upper top walls being connected to each other such that the upper housing forms a box body shape with a bottom opening, the upper top wall having a fan receiving port; the upper divider includes a partition box body and a pair of partition flanges, the partition box body having a pair of box body openings at both ends in the second direction, the pair of partition flanges disposed around and extending outwardly from the pair of box body openings respectively, the top of the partition box body having an upper fan opening; the pair of partition flanges are connected to the pair of second direction upper side walls and the upper top wall, respectively, and are spaced from the pair of first direction side walls by a certain distance to form a part of the upper suction channel, another part of the upper suction channel being formed inside the partition box body, and the upper fan opening forming an outlet of the upper suction channel; the partition box body is spaced apart from the upper top wall and the pair of second direction upper side walls to form the upper exhaust channel between the pair of partition flanges, the partition box body and the upper housing.

According to the above, the upper housing includes a housing insertion port disposed on one of the pair of first direction upper side walls, and the housing insertion port and the pair of box body openings are provided to collectively receive a heating element.

According to the above, the upper fan suction port is connected to an upper fan opening of the partition box body, and the upper fan exhaust port is disposed between the partition box body and the upper top wall and is in communication with the upper exhaust channel.

Other objects and advantages of the present application will be apparent from the description of the present application hereinafter with reference to the accompanying drawings, and may help with a full understanding of the present application. Brief Description of Drawings

Fig. 1 is a schematic diagram of a reflow oven in accordance with an embodiment of the present application;

Fig. 2A is a perspective view of the front side of two heating units in the reflow oven shown in Fig. 1 ;

Fig. 2B is a perspective view of the rear side of two heating units in the reflow oven shown in Fig. 1 ;

Fig. 2C is a top view of two heating units in the reflow oven shown in Figure 1 ;

Fig. 2D is an exploded view of two heating units in the reflow oven shown in Figure 1 ;

Fig. 3A is a cross-sectional view of the two heating units of Fig. 2A along the A-A line;

Fig. 3B is a cross-sectional view of the two heating units of Fig. 2A along the B-B line;

Fig. 4 is a perspective view of an upper fan of Fig. 2A;

Fig. 5A is a perspective view of a heating unit upper portion of Fig. 2A;

Fig. 5B is a perspective view of the reversed heating unit upper portion of Fig. 5A;

Fig. 5C is an exploded view of the heating unit upper portion of Fig. 5A viewed from top down;

Fig. 5D is an exploded view of the heating unit upper portion of Fig. 5A viewed from bottom up;

Fig. 6A is a perspective view of the heating unit lower portion of Fig. 2A;

Fig. 6B is a perspective view of the reversed heating unit lower portion of Fig. 6A;

Fig. 6C is an exploded view of the heating unit lower portion of Fig. 6A viewed from top down;

Fig. 6D is an exploded view of the heating unit lower portion of Fig. 6A viewed from bottom up.

Detailed Description

Various specific embodiments of the present application will be described below with reference to the attached drawings that form a part of the present specification. It should be understood that while terms denoting orientation, such as “front,” “rear,” “upper,” “lower,” “left,” “right,” “top,” “bottom,” “inside,” “outside,” “front side,” “rear side” etc., are used in the present application to describe various exemplary structural parts and elements of the present application, these terms are used herein for convenience of illustration only and are determined based on the exemplary orientations shown in the attached drawings. Since the embodiments disclosed in the present application may be disposed in different orientations, these terms denoting orientation are for illustrative purposes only and should not be considered as limiting.

Fig. 1 is a simplified schematic diagram of an embodiment of a reflow oven

100 according to an embodiment of the present application, which is an embodiment of the reflow oven of the present application. As shown in Fig. 1 , the reflow oven 100 includes a furnace chamber 112, a delivery channel 102, a heating zone 101 , and a cooling zone 105, where the delivery channel 102, the heating zone 101 , and the cooling zone 105 are disposed in the furnace chamber 112. Gas in the heating zone

101 is heated and gas in the cooling zone 105 is cooled. The delivery channel 102 extends through the heating zone 101 and the cooling zone 105 along the length direction (i.e., a first direction x) of the furnace chamber 112. The reflow oven 100 further includes a conveying device 118 disposed in the delivery channel 102. As one example, the conveying device 118 is a belt device. The conveying device 118 is used to pass a circuit board to be processed through the furnace chamber 112 along the delivery direction, for example, from the left end of the delivery channel 102 into the furnace chamber 112, and after being soldered in the length direction of the furnace chamber 112 (i.e., the first direction x) sequentially through the heating zone 101 and the cooling zone 105, the processed circuit board is output from the right end of the delivery channel 102.

As the circuit board (especially a sheet circuit board) passes through the heating zone 101 in the delivery channel 102, the circuit board may deform due to thermal effects, making the board edge of the circuit board easy to bend to cause warping.

Specifically, the heating zone 101 includes a plurality of heating units 110 disposed side by side in the furnace chamber 112 along the length direction (i.e., the first direction x) of the furnace chamber 112. Similarly, the cooling zone 105 also includes a plurality of cooling units 103, which are disposed side by side in the furnace chamber 112 along the first direction x. As one example, in the delivery direction of the reflow oven 100, the gas temperature in each heating unit 110 gradually increases and the gas temperature in each cooling unit 103 gradually decreases. The delivery channel 102 includes a plurality of delivery channel subregions 122 disposed side by side along the first direction x and in communication with each other. Each heating unit 110 includes a heating unit upper portion 114 and a heating unit lower portion 115, the delivery channel sub-regions 122 located in the heating zone 101 being located between the respective heating unit upper portion 114 and the heating unit lower portion 115, respectively. Similarly, the delivery channel sub-regions 122 located in the cooling zone 105 are located between the respective cooling unit upper and lower portions, respectively.

The reflow oven 100 further includes a pair of blocking boxes 108 disposed on the left and right ends of the furnace chamber 112, respectively, that is, the outside of the heating zone 101 and the cooling zone 105. When the reflow oven is using an inert gas (e.g., nitrogen) as the working gas, the pair of blocking boxes 108 are used to block the heating zone 101 and the cooling zone 105 in the furnace chamber 112 from communicating with the external environment so as to prevent air in the external environment from affecting the soldering quality.

The reflow oven 100 also includes a barrier exhaust zone 109 disposed between the heating zone 101 and the cooling zone 105. The barrier exhaust zone 109 may draw or exhaust gas from the furnace chamber 112, thereby impeding or reducing volatile pollutant containing gas from the heating zone 101 from entering the cooling zone 105, and as an insulation zone isolating the high temperature heating zone 101 from the low temperature cooling zone 105.

Figs. 2Ato 2D show the general structure of two side-by-side heating units 110, with Figs. 2A and 2B being stereoscopic views of the front and back of the two heating units, Fig. 2C being a top view of the two heating units, and Fig. 2D being an exploded view of the two heating units. As shown in Figs. 2A to 2D, the two heating units 110 are arranged side by side in a housing 204 in the first direction x and supported by a bracket 217. The heating unit upper portion 114 and the heating unit lower portion 115 of each heating unit 110 are spaced apart to form the delivery channel sub-region 122. The circuit board to be processed passes sequentially through the respective delivery channel sub-regions 122 in the first direction x. As one example, in a second direction y perpendicular to the first direction x, the circuit board is placed in the middle of the conveying device 118, that is, the circuit board passes through the delivery channel 102 from a middle region of each delivery channel sub-region 122 (see middle region 341 in Fig. 3B).

A heating element 221 is provided in the heating unit 110 to heat the gas in the heating unit 110. In the present embodiment, the heating element 221 is provided in the respective heating unit upper portion 114, and the heating element in the present embodiment is a heating rod. The heating element 221 extends from an exterior of the rear side of the heating unit upper portion 114 through the housing 204 into the interior of the heating unit upper portion 114 to heat the internal gas of the heating unit upper portion 114 such that the internal gas reaches a predetermined temperature. An upper fan 219 is provided in each heating unit upper portion 114, and a lower fan 220 is provided in each heating unit lower portion 115. The upper fan 219 and the lower fan 220 collectively drive the flow of gas inside the heating unit upper portion 114 and the heating unit lower portion 115 to form an internal circulation flow of gas so that the temperature of the gas inside the heating unit 110 is uniform.

Figs. 3A and 3B show more specific structures of the two side-by-side arranged heating units 110 to illustrate the passage of gas flow inside the heating units 110. Fig. 3A shows a cross-sectional view of the heating units 110 along the A- A line and Fig. 3B shows a cross-sectional view of the heating unit 110 along the B-B line.

As shown in Figs. 3A and 3B, the upper fan 219 has an upper fan suction port 336 and an upper fan exhaust port 335 located at the bottom, and the upper fan exhaust port 335 surrounds and is disposed above the upper fan suction port 336. The lower fan 220 has a lower fan suction port 337 and a lower fan exhaust port 338 located at the top, and the lower fan exhaust port 338 surrounds and is disposed below the lower fan suction port 337. As one example, the upper fan 219 and the lower fan 220 are centrifugal fans such that the gas discharged from the exhaust ports of each fan has a certain air pressure. The specific structure of the centrifugal fan will be detailed with reference to Fig. 4. Under the drive of the upper fan 219 and the lower fan 220, the gas inside the heating unit 110 is discharged from the exhaust ports of each fan at a certain air pressure, and after flowing within the heating unit 110 according to a certain path, the gas is then inhaled into the suction ports of each fan. In particular, the heating unit upper portion 114 includes an upper housing 351 and an upper divider 352. The upper divider 352 is disposed within the upper housing 351 and separates within the upper housing 351 to form an upper suction channel 333 and an upper exhaust channel 331 . The heating unit lower portion 115 includes a lower housing 361 and a lower divider 362. The lower divider 362 is disposed within the lower housing 361 and separates within the lower housing 361 to form a lower suction channel 332 and a lower exhaust channel 334. The upper exhaust channel 331 and the lower suction channel 332 are shown in the first direction x in Fig. 3A and the upper suction channel 333 and the lower exhaust channel 334 are shown in the second direction y in Fig. 3B. In the second direction y, the delivery channel sub-region 122 includes a middle region 341 located in the middle and side regions 342 located on both sides of the central region 341 . An outlet 353 of the upper exhaust channel 331 is located directly above the middle region 341 of the delivery channel sub-region 122, and an inlet 354 of the lower suction channel 332 is located directly below the middle region 341 of the delivery channel sub-region 122. The lower fan suction port 337 is also located directly below the middle region 341 of the delivery channel sub-region 122 and there is no lower divider 362 between the lower fan suction port and the middle region 341 of the delivery channel sub-region 122 so that the lower suction channel 332 is not blocked.

As such, as shown in Fig. 3A, the gas discharged from the upper fan exhaust port 335 flows through the upper exhaust channel 331 and blows towards the middle region 341 of the delivery channel sub-region 122, and is subsequently sucked by the lower suction channel 332 and delivered to the lower fan suction port 337, and the gas discharged from the lower fan exhaust port 338 sequentially flows through the lower exhaust channel 334, the side region 342 of the delivery channel subregion 122 and the upper suction channel 333 to be received by the upper fan suction port 336.

The heating unit upper portion 114 and the heating unit lower portion 115 of each heating unit 110 and the delivery channel sub-region 122 located between the heating unit upper portion 114 and the heating unit lower portion 115 collectively form a heated gas internal circulation passage 345. The heated gas internal circulation passage 345 includes a forward passage 347 for the heated gas to flow from top to bottom as shown in Fig. 3A, and a backward passage 348 for the heated gas to flow from bottom to top as shown in Fig. 3B. That is, the forward passage 347 includes the upper exhaust channel 331 , the middle region 341 of the delivery channel subregion 122, and the lower suction channel 332, the upper exhaust channel 331 and the lower suction channel 332 communicating through the middle region 341 of the delivery channel sub-region 122. The backward passage 348 includes the upper suction passage 333, the side regions 342 of the delivery passage sub-region 122, and the lower exhaust passage 334, the upper suction passage 333 and the lower exhaust passage 334 communicating through the side regions 342 of the delivery passage sub-region 122. Thus, when the gas in the heated gas inner circulation passage 345 flows through the delivery channel sub-region 122 in different directions, the gas flows through different regions of the delivery channel sub-region 122.

When the circuit board to be processed passes through the middle region 341 of the delivery channel sub-region 122 in the first direction x, the circuit board is located in the forward passage 347 and the gas in the heating unit 110 flows from top to bottom. The air pressure of the gas flow acts on the circuit board, causing downward pressure on one side of the circuit board and downward suction on the other. This prevents warping of the circuit board by affixing the circuit board to the conveying device 118, such as a belt device, even if the circuit board is affected by thermal effects. Especially for a sheet circuit board, because of its flexibility, it is more pronounced that the pressure and suction generated by the air pressure of gas flow on the sheet circuit board avoids warping of the sheet circuit board. Moreover, for the sheet circuit board, generally the required amount of heating is not large, and the heating demand can be met by only providing the heating element 221 in the heating unit upper portion 114 without providing a heating element in the heating unit lower portion 115, and it makes the sheet circuit board more likely to have “U” shaped warping deformations in which each board edge is bent upwards. Air pressure of the gas flow acts on the edge of the sheet circuit board that is easily bent and deformed upwards, making it close to the conveying device 118 below, thus having a better effect of preventing warping and deformation.

Moreover, there is no lower divider 362 between the lower fan suction port 337 and the middle region 341 of the delivery channel sub-region 122, which can make the suction of the lower fan suction port 337 act more directly on the circuit board, so that the circuit board is flat against the conveying device 118. The heating unit 110 further includes a heating element support 326 provided in the heating unit upper portion 114 and supported on the upper divider 352, and in the present embodiment, the heating element support 326 is supported on the upper divider 352. The heating element support 326 is used to secure the end of the heating element 221 after the heating element 221 extends into the heating unit upper portion 114. This allows the heating element 221 to be fixed even if its length is long. In some other embodiments, a heating element and a heating element support may also be provided in the heating unit lower portion 115, and the heating element support may be supported on the lower divider 362.

The heating unit 110 further includes an upper multiwell plate 316 and a lower multiwell plate 313, the upper multiwell plate 316 and the lower multiwell plate 313 being uniformly disposed with a plurality of apertures. The upper multiwell plate 316 is disposed in the heating unit upper portion 114 and is disposed at the outlet 353 of the upper exhaust channel 331 . The upper multiwell plate 316 is disposed such that gas discharged from the upper exhaust channel 331 needs to flow through the upper multiwell plate 316 before it flows to the middle region 341 of the delivery channel sub-region 122 to evenly diffuse gas in the upper exhaust channel 331 towards the middle region 341 of the delivery channel sub-region 122. The lower multiwell plate 313 is provided in the heating unit lower portion 115 and is provided at the inlet 354 of the lower suction channel 332. The lower multiwell plate 313 is disposed such that gas flowing through the middle region 341 of the delivery channel sub-region 122 needs to flow through the lower multiwell plate 313 before it enters the lower suction channel 332 to evenly suck gas into the lower suction channel 332 from the middle region 341 of the delivery channel sub-region 122. By providing the upper multiwell plate 316 and the lower multiwell plate 313, the gas temperature at the middle region 341 of the delivery channel sub-region 122 is generally uniform, and the pressure and suction received by the circuit board in the middle region 341 of the delivery channel sub-region 122 is also generally uniform.

Fig. 4 illustrates a stereoscopic structure of the upper fan 219 of the present application, the lower fan 220 having a similar structure, which is not repeated herein. As shown in Fig. 4, the upper fan 219 is a centrifugal fan. The upper fan 219 has a motor part 423 and a spool 424 connected to the motor part 423. The upper fan 219 also includes a plurality of blades 439 disposed around and connected to the spool 424 spaced apart. The motor part 423 drives the spool 424 to rotate, which causes the blade 439 to rotate about the axis of the spool 424 when the spool 424 is rotated. The upper fan suction port 336 forms at the bottom of the upper fan 219 and gas can enter among these blades 439 from the upper fan suction port 336. These openings spaced in the circumferential direction by adjacent blades 439 form the upper fan exhaust ports 335 from which gas can be discharged.

When the motor part 423 drives the spool 424 to rotate, gas enters among the blades 439 axially along the spool 424 from the upper fan suction port 336 at the bottom of the upper fan 219, and the rotation of the blades 439 increases the gas pressure and changes the gas flow direction to radial so that the gas is discharged from the upper fan exhaust port 335. As such, the gas discharged from the upper fan exhaust port 335 has a certain air pressure.

Figs. 5Ato 5D show specific structures of the heating unit upper portion 114 according to one embodiment of the present application. Here, Fig. 5A is a perspective view of the heating unit upper portion 114, Fig. 5B is a perspective view of the reversed heating unit upper portion 114, Fig. 5C is an exploded view of the heating unit upper portion 114 viewed from top down, and Fig. 5D is an exploded view of the heating unit upper portion 114 viewed from bottom up.

As shown in Figs. 5Ato 5D, the upper housing 351 of the heating unit upper portion 114 is generally in the shape of a rectangular box body having a bottom opening 584 having a width direction that coincides with the first direction x and a length direction that coincides with the second direction y. The upper housing 351 includes a pair of first direction upper side walls 581 , a pair of second direction upper side walls 582, and an upper top wall 583, which are connected to each other. The pair of first direction upper side walls 581 extend along the first direction x and the pair of second direction upper side walls 582 extend along the second direction y. The upper top wall 583 has a fan receiving port 585. The upper fan 219 is mounted on the upper top wall 583, its upper fan exhaust port 335 and the upper fan suction port 336 extend through the fan receiving port 585 below the upper top wall 583, and its motor part 423 is disposed on the upper top wall 583.

The upper divider 352 includes a partition box body 586 and a pair of partition flanges 587. The partition box body 586 is roughly rectangular box body shaped with its width direction in the first direction x and its length direction in the second direction y. The partition box body 586 has a pair of box body openings 588 at both front and rear ends in the second direction y, the pair of partition flanges 587 being respectively disposed around the pair of box body openings 588 and extending outwardly from the partition box body 586. Each wall of the partition box body 586 is generally parallel to the upper housing 351 , but smaller in size than the upper housing 351 . In the present embodiment, the pair of side walls of the partition box body 586 extending along the second direction y are generally parallel to and spaced from the pair of second direction upper side walls 582 of the upper housing 351 by a certain distance, the top and bottom of the partition box body 586 are generally parallel to the upper top wall 583 of the upper housing 351 , and the top is spaced a certain distance from the upper top wall 583. A pair of partition flanges 587 are generally parallel to and spaced a certain distance from the pair of first direction upper side walls 581 of the upper housing 351 , and the pair of partition flanges 587 are connected to the second direction upper side walls 582 and the upper top wall 583. In this way, the upper suction channel 333 and the upper exhaust channel 331 can be formed by the upper divider 352 and the upper housing 351 .

Specifically, the top of the partition box body 586 has an upper fan opening 589 to which the upper fan suction port 336 of the upper fan 219 is connected so that the upper fan suction port 336 is in fluid communication with the interior of the partition box body 586 through the upper fan opening 589. The pair of partition flanges 587 respectively extend upwardly from the outer edge of the box body opening 588 to connect with the upper top wall 583 of the upper housing 351 and extend in the first direction x to connect with the pair of second direction upper side walls 582. As such, the space between the pair of partition flanges 587 and the pair of first direction upper side walls 581 forms a part of the upper suction channel 333, and the interior of the partition box body 586 forms another part of the upper suction channel 333. The upper fan opening 589 forms an outlet of the upper suction channel 333.

The upper fan exhaust port 335 of the upper fan 219 is disposed between the top of the partition box body 586 and the upper top wall 583 and is in communication with the upper exhaust channel 331 . As such, the space spaced between the top of the partition box body 586 and the upper top wall 583 of the upper housing 351 , and the space spaced between the pair of side walls extending in the second direction y of the partition box body 586 and the pair of second direction upper side walls 582 of the upper housing 351 collectively form the upper exhaust channel 331 . After the gas in the upper exhaust channel 331 is discharged from the upper fan exhaust port 335, the gas enters the space between the partition box body 586 and the upper top wall 583 and flows through the space between the partition box body 586 and the pair of second direction upper side walls 582 to the middle region 341 of the delivery channel sub-region 122.

After the gas in the upper suction channel 333 flows out of the side region 342 of the delivery channel sub-region 122, the gas enters the space between the partition flange 587 and the first direction upper side wall 581 , and then enters the interior of the partition box body 586 through the box body opening 588 and is finally received by the upper fan suction port 336.

The upper multiwell plate 316 is connected at the bottom of the upper housing 351 . In the present embodiment, the upper multiwell plate 316 is connected with the pair of partition flanges 587 in the second direction y and the upper multiwell plate 316 is connected with the pair of second direction upper side walls 582 in the first direction x. In this way, the gas in the upper exhaust channel 331 needs to flow through the upper multiwell plate 316 before being delivered to the middle region 341 of the delivery channel sub-region 122 so that the gas can spread evenly towards the middle region 341 .

A housing insertion port 590 is provided on one of the first direction upper side walls 581 of the upper housing 351 . The position of the housing insertion port 590 corresponds to the position of the box body opening 588 to collectively receive the heating element 221 . Thus, the heating element 221 is able to extend through the housing insertion port 590 and the box body opening 588 into the interior of the partition box body 586. As one example, the other end of the heating element 221 protrudes from the opposite box body opening 588.

It can be understood that those skilled in the art can also set other upper housing and upper divider structures according to specific needs, as long as the upper suction channel and upper exhaust channel corresponding to the delivery channel sub-region can be formed.

Figs. 6Ato 6D illustrate specific structures of the heating unit lower portion 115 according to one embodiment of the present application. Here, Fig. 6A is a perspective view of the heating unit lower portion 115, Fig. 6B is a perspective view of the reversed heating unit lower portion 115, Fig. 6C is an exploded view of the heating unit lower portion 115 viewed from top down, and Fig. 6D is an exploded view of the heating unit lower portion 115 viewed from bottom up.

As shown in Figs. 6Ato 6D, the shape of the lower housing 361 of the heating unit lower portion 115 is generally similar to the shape of the upper housing 351 of the heating unit upper portion 114, being a rectangular box body shape with a top opening 667 having a width direction consistent with the first direction x and a length direction consistent with the second direction y. The lower housing 361 includes a pair of first direction lower side walls 664, a pair of second direction lower side walls 665, and a lower bottom wall 666 that are mutually connected. The pair of first direction lower side walls 664 extend along the first direction x and the pair of second direction lower side walls 665 extend along the second direction y. The lower bottom wall 666 has a fan receiving port 668. The lower fan 220 is mounted on the lower bottom wall 666 with the lower fan exhaust port 338 and the lower fan suction port 337 protruding above the lower bottom wall 666 through the fan receiving port 668 from bottom to top with its motor part disposed below the lower bottom wall 666.

The lower divider 362 includes a transverse partition 669 and a pair of vertical partitions 670. The width direction of the transverse partition 669 is the first direction x and its length direction is the second direction y. The pair of vertical partitions 670 are located above the transverse partition 669 and are connected to both ends of the transverse partition 669 in the second direction y. In the present embodiment, the transverse partition 669 is generally parallel to and spaced by a certain distance from the lower bottom wall 666 of the lower housing 361 , the pair of vertical partitions 670 are generally parallel to and spaced by a certain distance from the pair of first direction lower side walls 664, and each vertical partition 670 is connected to the pair of second direction lower side walls 665. As such, the lower suction channel 332 and the lower exhaust channel 334 can be formed by the lower partition 362 and the lower housing 361 .

In particular, the transverse partition 669 extends along the first direction x to be connected with the pair of second direction lower side walls 665. The transverse partition 669 has a lower fan opening 671 to which the lower fan suction port 337 of the lower fan 220 is connected so that the lower fan suction port 337 is in fluid communication with the space above the transverse partition 669 through the lower fan opening 671 . The pair of vertical partitions 670 are formed extending upwardly from the edges of both ends of the transverse partition 669 in the second direction y, respectively, and extend along the first direction x to be connected with the pair of second direction lower side walls 665. As such, the transverse partition 669, the pair of vertical partitions 670, and the pair of second direction lower side walls 665 collectively form the lower suction channel 332. The lower fan opening 671 forms an outlet of the lower suction channel 332.

The lower fan exhaust port 338 of the lower fan 220 is disposed between the transverse partition 660 and the lower bottom wall 666 and is in communication with the lower exhaust channel 334. As such, the space spaced between the transverse partition 660 and the lower bottom wall 666 forms a part of the lower exhaust channel 334, and the space spaced between the pair of vertical partitions 670 and the pair of first direction lower side walls 664 forms another part of the lower exhaust channel 334.

After the gas in the lower exhaust channel 334 is discharged from the lower fan exhaust port 338, the gas enters the space between the transverse partition 660 and the lower bottom wall 666 and flows through the space between the pair of vertical partitions 670 and the pair of first direction lower side walls 664 to the side region 342 of the delivery channel sub-region 122.

After the gas in the lower suction channel 332 flows out of the middle region 341 of the delivery channel sub-region 122, the gas enters the space above the transverse partition 660 and is then received by the lower fan suction port 337.

The lower multiwell plate 313 is connected at the top of the lower housing 361 . In the present embodiment, the lower multiwell plate 313 is connected with the pair of vertical partitions 670 in the second direction y and the lower multiwell plate 313 is connected with the pair of second direction lower side walls 665 in the first direction x. In this way, the middle region 341 of the delivery channel sub-region 122 needs to flow through the lower multiwell plate 313 before being delivered to the lower suction channel 332, enabling the gas to be uniformly delivered from the middle region 341 to the lower suction channel 332.

A housing insertion port 672 is provided on one of the first direction lower side walls 664 of the lower housing 361 . The lower divider 362 further includes a pair of heating element insertion ports 673, which are respectively provided on the pair of vertical partitions 670. The lower divider 362 further includes a pair of spacer rings 674 disposed around the pair of heating element insertion ports 673, respectively, and between the pair of vertical partitions 670 and the corresponding first direction lower side walls 664. The position of the housing insertion port 672 corresponds to the position of the pair of heating element insertion ports 673 to collectively receive the heating element 221 .Thus, the heating element 221 is capable of passing through the housing insertion port 672 and the heating element insertion port 673 to extend over the transverse partition 669. Furthermore, the spacer ring 674 can also isolate the heating element insertion port 673 from the lower exhaust channel 334 so that the lower suction channel 332 and the lower exhaust channel 334 cannot communicate with each other through the heating element insertion port 673, whereby the lower suction channel 332 can also be isolated from the lower exhaust channel 334.

It can be understood that those skilled in the art can also set other lower housing and lower partition structures according to specific needs, as long as the lower suction channel and lower exhaust channel corresponding to the delivery channel sub-region can be formed.

In some reflow ovens, to prevent warping of the circuit board when heated, it is necessary to use a vehicle to fix the edge of the circuit board in advance, which requires a large labor cost and the process is complicated. In the reflow oven of the present application, by changing the flow direction of the exhaust channel and the suction channel of the heating unit lower portion, the circuit board is simultaneously subjected to downward pressure and suction while flowing through the delivery channel sub-region so as to prevent the circuit board from warping and deforming, which greatly improves the soldering yield of the circuit board and is particularly beneficial for soldering of the sheet circuit board. Moreover, the reflow oven of the present application eliminates the use of vehicles to pre-fix circuit boards, thus simplifying the process and reducing the labor cost of the product. In addition, the reflow oven of the present application only needs to change the structure of the lower divider of the heating unit lower portion on the basis of the heating unit structure of the existing reflow oven, and the cost of retrofitting is low.

Although the present disclosure has been described in connection with examples of the embodiments outlined above, various alternatives, modifications, variations, improvements, and/or substantial equivalents, whether known or foreseeable now or in the near future, may be apparent to those having at least ordinary skill in the art. In addition, the technical effects and/or technical problems described in the present specification are exemplary and not limiting; therefore, the disclosure in the present specification may be used to solve other technical problems and have other technical effects and/or may solve other technical problems.

Therefore, examples of embodiments of the present disclosure as set forth above are intended to be illustrative and not limiting. Various changes may be made without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is intended to include all known or earlier developed alternatives, modifications, variations, improvements and/or substantial equivalents.

Claims

CLAIMS What is claimed is:

1 . A reflow oven comprising: a furnace chamber; a plurality of heating units disposed side by side in the furnace chamber along a first direction, each of the heating units comprises a heating unit upper portion and a heating unit lower portion; a delivery channel extending through the plurality of heating units along the first direction and comprises a plurality of delivery channel sub-regions respectively located between the heating unit upper portion and the heating unit lower portion of each heating unit, the delivery channel sub-regions comprises in a second direction perpendicular to the first direction a middle region for passing a processing element through and side regions located on opposite sides of the middle region; wherein the heating unit upper portion includes an upper fan, an upper suction channel, and an upper exhaust channel, the upper fan having an upper fan suction port and an upper fan exhaust port; the heating unit lower portion includes a lower fan, a lower suction channel, and a lower exhaust channel, the lower fan having a lower fan suction port and a lower fan exhaust port; wherein the upper suction channel, the upper exhaust channel, the lower suction channel, and the lower exhaust channel are configured such that gas discharged from the upper fan exhaust port flows through the upper exhaust channel and blows to the middle region of the delivery channel sub-region, then is sucked by the lower suction channel and delivered to the lower fan suction port, and the gas discharged from the lower fan exhaust port sequentially flows through the lower exhaust channel, the side regions of the delivery channel sub-region and the upper suction channel, and is then received by the upper fan suction port.

2. The reflow oven according to Claim 1 , wherein: the heating unit upper portion and the heating unit lower portion of each heating unit and the delivery channel sub-region located between the heating unit upper portion and the heating unit lower portion collectively form a heated gas internal circulation passage; wherein the heated gas internal circulation passage includes a forward passage for heated gas to flow from top to bottom and a backward passage for the heated gas to flow from bottom to top, wherein the forward passage includes the upper exhaust channel, the middle region of the delivery channel sub-region and the lower suction channel, and the backward passage includes the lower exhaust channel, the side regions of the delivery channel sub-region and the upper suction channel.

3. The reflow oven according to Claim 2, wherein: the heating unit upper portion includes an upper housing and an upper divider disposed within the upper housing, the upper fan suction port and the upper fan exhaust port are disposed within the upper housing, the upper suction channel and the upper exhaust channel are formed by the upper divider and the upper housing, the outlet of the upper exhaust channel is located directly above the middle region of the delivery channel sub-region; the heating unit lower portion includes a lower housing and a lower divider disposed within the lower housing, and the lower fan suction port and the lower fan exhaust port are disposed within the lower housing, the lower suction channel and the lower exhaust channel are formed by the lower divider and the lower housing, the inlet of the lower suction channel is located directly below the middle region of the delivery channel sub-region.

4. The reflow oven according to Claim 3, wherein: the lower fan suction port is located directly below the middle region of the delivery channel sub-region, and there is no lower divider between the lower fan suction port and the middle region of the delivery channel sub-region.

5. The reflow oven according to Claim 4, wherein: the lower housing of the heating unit lower portion includes a pair of first direction lower side walls extending in the first direction, a pair of second direction lower side walls extending in a second direction, and a lower bottom wall, the first direction lower side walls, the second direction lower side walls and the lower bottom wall being connected to each other such that the lower housing forms a box body shape with a top opening, the lower bottom wall having a fan receiving port; the lower divider includes a transverse partition and a pair of vertical partitions located above the transverse partitions and connected to both ends of the transverse partition in the second direction, the transverse partition having a lower fan opening; wherein the transverse partition and the pair of vertical partitions are all connected to the pair of second direction lower side walls to collectively form the lower suction channel through the transverse partition, the pair of vertical partitions and the pair of second direction lower side walls, the lower fan opening forming an outlet of the lower suction channel; wherein the transverse partition is spaced from the lower bottom wall by a certain distance to form a part of the lower exhaust channel, and the pair of vertical partitions are spaced from the pair of first direction lower side walls by a certain distance, respectively, to form another part of the lower exhaust channel.

6. The reflow oven according to Claim 5, wherein: the lower fan suction port is connected to a lower fan opening of the transverse partition, and the lower fan exhaust port is disposed between the transverse partition and the lower bottom wall and in communication with the lower exhaust channel.

7. The reflow oven according to Claim 5, wherein: the lower housing includes a housing insertion port disposed on one of the pair of first direction lower side walls; the lower divider further includes a pair of heating element insertion ports disposed on the pair of vertical partitions, respectively; the lower divider further includes a pair of spacer rings disposed around the pair of heating element insertion ports respectively and between the pair of vertical partitions and the first direction lower side walls to isolate the lower suction channel and the lower exhaust channel while being able to receive a heating element.

8. The reflow oven according to Claim 4, wherein: the upper housing of the heating unit upper portion includes a pair of first direction side walls extending in the first direction, a pair of second direction side walls extending in the second direction, and an upper top wall, the first direction upper side walls, the second direction upper side walls and the upper top walls being connected to each other such that the upper housing forms a box body shape with a bottom opening, the upper top wall having a fan receiving port; the upper divider includes a partition box body and a pair of partition flanges, the partition box body having a pair of box body openings at both ends in the second direction, the pair of partition flanges disposed around and extending outwardly from the pair of box body openings respectively, the top of the partition box body having an upper fan opening; the pair of partition flanges are connected to the pair of second direction upper side walls and the upper top wall, respectively, and are spaced from the pair of first direction side walls by a certain distance to form a part of the upper suction channel, another part of the upper suction channel being formed inside the partition box body, and the upper fan opening forming an outlet of the upper suction channel; the partition box body is spaced apart from the upper top wall and the pair of second direction upper side walls to form the upper exhaust channel between the pair of partition flanges, the partition box body and the upper housing.

9. The reflow oven according to Claim 8, wherein: the upper housing includes a housing insertion port disposed on one of the pair of first direction upper side walls, and the housing insertion port and the pair of box body openings are provided to collectively receive a heating element.

10. The reflow oven according to Claim 9, wherein: the upper fan suction port is connected to an upper fan opening of the partition box body, and the upper fan exhaust port is disposed between the partition box body and the upper top wall and is in communication with the upper exhaust channel.

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