System and method for combined wave soldering flow design

Abstract

To provide a method for adjusting the flow of a solder wave of a wave soldering machine.SOLUTION: A wave soldering station includes a solder pot having a reservoir of solder material, a flow conduit positioned within the reservoir of the solder pot, and a wave soldering nozzle assembly coupled to the flow conduit. The wave soldering nozzle assembly has a solder distribution baffle configured to create a solder wave, a throttle gate coupled to the flow conduit and configured to move from an open position to allow full flow of solder through the solder distribution baffle and a closed position to block a portion of the flow of solder through the solder distribution baffle, and an exit wing coupled to the flow conduit and configured to move from a lowered position to allow increased solder flow and a raised position to reduce solder flow. A controller controls the movement of the throttle gate and the exit vanes.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates generally to apparatus and methods for manufacturing printed circuit boards and for assisting in the process of soldering metal to integrated circuit boards, and more particularly to wave soldering machines and related methods having wave solder nozzle assemblies configured to control solder flow. [Background technology]

[0002] In the manufacture of printed circuit boards, electronic components can be mounted on them by a process known as "wave soldering." In a typical wave soldering machine, a conveyor moves printed circuit boards (sometimes called "PCBs") on an inclined path through a flux application station, a preheat station, and finally a wave soldering station. At the wave soldering station, a wave of solder is ejected (by a pump) upward through a wave solder nozzle and contacts the portion of the printed circuit board to be soldered.

[0003] A typical wave solder nozzle has a nozzle configured to control the flow of solder produced by a wave soldering machine. The process of adjusting the solder flow can be difficult and poses risks to an operator tasked with making such adjustments in a solder pot filled with molten solder. It is also desirable to minimize dross created by the solder flow on the nozzle. Summary of the Invention

[0004] One aspect of the present disclosure relates to a wave soldering machine for performing wave soldering operations on printed circuit boards. In one embodiment, the wave soldering machine includes a housing and a conveyor coupled to the housing. The conveyor is configured to deliver (pump) printed circuit boards through the housing. The wave soldering machine further includes a wave soldering station coupled to the housing. The wave soldering station includes a solder pot having a reservoir of solder material, a flow conduit positioned within the reservoir of the solder pot, and a wave soldering nozzle assembly coupled to the flow conduit. The wave soldering nozzle assembly includes a solder distribution baffle configured to generate a solder wave, a throttle gate coupled to the flow conduit and configured to move from an open position to allow complete flow of solder through the solder distribution baffle and a closed position to block a portion of the solder flow through the solder distribution baffle, and an exit vane coupled to the flow conduit and configured to move from a lowered position to allow increased solder flow and a raised position to reduce solder flow. The wave soldering machine further includes a controller coupled to the wave soldering station that controls movement of the throttle gate and exit vanes to control solder flow.

[0005] An embodiment of the wave soldering machine may further include configuring the wave soldering nozzle assembly to include a core frame supported by the flow conduit. The core frame may be configured to support a solder dispensing baffle. The outlet vanes may be rotatable about hinges relative to the nozzle core frame to move the outlet vanes between lowered and raised positions. The wave solder nozzle assembly may further include an outlet vane actuator connected to the outlet vane and coupled to a controller. The outlet vane actuator may be configured to adjust the position of the outlet vane between the lowered and raised positions. The outlet vane actuator may be connected to the outlet vane by a linkage, the linkage including at least one rotation link having a first end rotatably coupled to an end of the outlet vane and a second end rotatably coupled to an actuator arm of the outlet vane actuator. The linkage may further include a crossbar extending perpendicular to the at least one rotation link and rotatably coupled to the at least one rotation link, and at least one connecting link connecting the crossbar to the actuator arm and extending perpendicular to the crossbar. The at least one connecting link may be connected to the actuator arm by an actuator block. The throttle gate may include a plate and a hinge pin hingedly secured to the nozzle core frame. The wave soldering nozzle assembly may further include a throttle gate actuator configured to move the throttle gate between an open position and a closed position. The wave soldering nozzle assembly may further include a link secured to a movement mechanism coupled to the throttle plate. The movement mechanism may be coupled to an arm secured to the hinge pin of the throttle gate.

[0006] Another aspect of the present disclosure relates to a wave soldering station of a wave soldering machine configured to perform wave soldering operations on printed circuit boards. In one embodiment, the wave soldering station includes a solder pot having a reservoir of solder material, a flow conduit positioned within the reservoir of the solder pot, and a wave soldering nozzle assembly coupled to the flow conduit. The wave soldering nozzle assembly includes a solder distribution baffle configured to generate a solder wave, a throttle gate coupled to the flow conduit and configured to move from an open position to allow full flow of solder through the solder distribution baffle and a closed position to block a portion of the solder flow through the solder distribution baffle, and an exit vane coupled to the flow conduit and configured to move from a lowered position to allow increased solder flow and a raised position to decrease solder flow. A controller coupled to the wave soldering station is configured to control movement of the throttle gate and the exit vane to control the solder flow.

[0007] An embodiment of the wave soldering station may further include configuring the wave soldering nozzle assembly to include a core frame supported by the flow conduit. The core frame may be configured to support a solder dispensing baffle. The outlet vanes may be rotatable about hinges relative to the nozzle core frame to move the outlet vanes between lowered and raised positions. The wave solder nozzle assembly may further include an outlet vane actuator connected to the outlet vane and coupled to a controller. The outlet vane actuator may be configured to adjust the position of the outlet vane between the lowered and raised positions. The outlet vane actuator may be connected to the outlet vane by a linkage, the linkage including at least one rotation link having a first end rotatably coupled to an end of the outlet vane and a second end rotatably coupled to an actuator arm of the outlet vane actuator. The linkage may further include a crossbar extending perpendicular to the at least one rotation link and rotatably coupled to the at least one rotation link, and at least one connecting link connecting the crossbar to the actuator arm and extending perpendicular to the crossbar. The at least one connecting link may be connected to the actuator arm by an actuator block. The throttle gate may include a plate and a hinge pin hingedly secured to the nozzle core frame. The wave soldering nozzle assembly may further include a throttle gate actuator configured to move the throttle gate between an open position and a closed position. The wave soldering nozzle assembly may further include a link secured to a movement mechanism coupled to the throttle plate. The movement mechanism may be coupled to an arm secured to the hinge pin of the throttle gate.

[0008] Yet another aspect of the present disclosure relates to a method for adjusting a solder wave flow of a wave solder nozzle assembly of a wave soldering machine. In one embodiment, the method includes delivering solder material to a wave solder nozzle assembly having a solder distribution baffle configured to produce a solder wave, a throttle gate coupled to a flow conduit and configured to move from an open position to allow full flow of solder through the solder distribution baffle and a closed position to block a portion of the solder flow through the solder distribution baffle, and exit wings coupled to the flow conduit and configured to move from a lowered position to allow increased solder flow and a raised position to decrease solder flow, adjusting the flow of the solder wave with a throttle gate actuator connected to the throttle gate to adjust the position of the throttle gate and an exit wing actuator coupled to the exit wing to adjust the position of the exit wing relative to a nozzle core frame, and performing a wave soldering operation on a printed circuit board.

[0009] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in various figures is represented by a like reference numeral. For purposes of clarity, not every component may be labeled in every figure. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of a wave soldering machine. [Figure 2] FIG. 1 is a side view of a wave soldering machine with the outer packaging removed to reveal the internal components of the wave soldering machine. [Figure 3] FIG. 1 is a perspective view of a wave soldering station according to one embodiment of the present disclosure. [Figure 4] 1 is a cross-sectional view of a wave soldering station with the wave soldering assembly separated from the solder pot of the wave soldering station. [Figure 5] FIG. 1 is a perspective view of a wave soldering assembly. [Figure 6] FIG. 2 is another perspective view of the wave soldering assembly. [Figure 7] FIG. 1 is an exploded perspective view of a wave soldering assembly. [Figure 8] FIG. 10 is a side view of the wave soldering assembly showing the exit wings in the lowered position. [Figure 9] FIG. 10 is a side view of the wave soldering assembly showing the exit wings in a raised position. [Figure 10] FIG. 10 is a side view of the wave soldering assembly showing the throttle gate in a closed position. [Figure 11] FIG. 10 is a side view of the wave soldering assembly showing the throttle gate in the open position. [Figure 12] FIG. 10 is an enlarged cross-sectional view of the outlet vane in a raised position and the throttle gate in an open position. [Figure 13] FIG. 10 is an enlarged cross-sectional view of the outlet vane in the lowered position and the throttle gate in the closed position. [Figure 14] 13 is a cross-sectional view similar to FIG. 12 showing solder flow through the wave soldering assembly. [Figure 15] 14 is a cross-sectional view similar to FIG. 13 showing solder flow through the wave soldering assembly. [Figure 16] 15 is a cross-sectional view similar to FIGS. 12 and 14 showing the flow of solder through the wave soldering assembly and a printed circuit board passing over the solder wave. FIG. [Figure 17] 16 is a cross-sectional view similar to FIGS. 13 and 15 showing the flow of solder through the wave soldering assembly and a printed circuit board passing over the solder wave. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The present disclosure is capable of other embodiments and of being practiced or carried out in various ways. Moreover, the phraseology and terminology used in this disclosure is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," "having," "containing," "involving," and variations thereof in this disclosure is intended to encompass the previously listed items and equivalents thereof as well as additional items.

[0012]

[0003] Embodiments of the present disclosure relate to controlling the flow of molten solder on a nozzle to optimize the flow of a solder wave. One objective is to provide the ability to adjust the contact of the solder wave with a printed circuit board. Another objective is to adjust the solder flow at the exit of the solder wave to optimize soldering characteristics. A further objective is to automate these adjustments and enable computer control to eliminate the need for human intervention when adjustments are necessary based on the product being processed.

[0013] For illustrative purposes, and with reference to FIG. 1 , embodiments of the present disclosure will be described below with respect to a wave soldering machine, generally designated 10, used to apply solder to printed circuit boards 12. Wave soldering machine 10 is one of several machines in a printed circuit board manufacturing / assembly line. As shown, wave soldering machine 10 includes a housing or frame 14 adapted to house the machine's components. A conveyor 16 is arranged to deliver printed circuit boards to be processed by wave soldering machine 10. Upon entering wave soldering machine 10, each printed circuit board 12 travels along an inclined path (e.g., 6 degrees relative to horizontal) along conveyor 16 through tunnel 18, which includes a flux application station, generally designated 20, and a preheat station, generally designated 22, to condition the printed circuit board for wave soldering. Once conditioned (i.e., heated), printed circuit board 12 travels to a wave soldering station, generally designated 24, which applies solder material to the printed circuit board. A controller 26 is provided to automate the operation of several stations of the wave soldering machine 10, including, but not limited to, the fluxing station 20, the preheating station 22, and the wave soldering station 24, in a known manner.

[0014] Referring to FIG. 2 , the flux application station 20 is configured to apply flux to printed circuit boards moving on the conveyor 16 through the wave soldering machine 10. The preheating station includes several preheaters (e.g., preheaters 22a, 22b, and 22c) designed to gradually increase the temperature of printed circuit boards moving through the tunnel 18 and along the conveyor 16 to prepare the printed circuit boards for the wave soldering process. As shown, and as described in more detail below, the wave soldering station 24 includes a wave solder nozzle assembly in fluid communication with a reservoir of solder material. A pump is provided within the reservoir to deliver molten solder material from the reservoir to the wave soldering nozzle assembly. Once soldered, the printed circuit boards exit the wave soldering machine 10 via the conveyor 16 to another station in the production line, such as a pick-and-place machine.

[0015] In some embodiments, the wave soldering machine 10 can further include a flux management system, generally designated 28, that removes volatile contaminants from the tunnel 18 of the wave soldering machine. As shown in FIG. 2, the flux management system 28 is located below the preheat station 22. In one embodiment, the flux management system is supported by the housing 14 within the wave soldering machine and in fluid communication with the tunnel 18, which is shown schematically in FIG. 2. The flux management system 28 is configured to receive contaminated gas from the tunnel 18, treat the gas, and return clean gas to the tunnel. The flux management system 28 is particularly configured to remove volatile contaminants from the gas, particularly in an inert atmosphere.

[0016] Embodiments of the present disclosure relate to varying the contact length (also referred to as "dwell time"), which is the amount of time the PCB is in contact with the solder wave. Because PCBs vary in size, mass, shape, composition, etc., resulting in a wide range of process windows, a "one size fits all" approach to dwell time is not necessarily the most effective approach. If the soldering process is not effectively optimized, it can lead to solder defects that result in rework or scrap.

[0017] Additionally, embodiments of the present disclosure relate to optimizing wave solder flow for printed circuit boards 12. When processing printed circuit boards 12, it is desirable to control the speed of the solder flow (Vs) to approximate the speed of the printed circuit board 12 as it exits the solder wave (Vpcb). When these two speeds are equal, the likelihood of soldering defects, particularly solder bridging, is significantly reduced. If the speed is not optimized, the resulting defects may require rework or scrap.

[0018] 3 and 4, in one embodiment, the wave soldering station 24 includes a solder pot 30 defining a reservoir 32 configured to contain molten solder. In one embodiment, the solder pot 30 is a box-shaped structure that supports the components of the wave soldering station 24, including a flow conduit 34 having one or more chambers within the reservoir 32. The flow conduit 34 is designed to deliver pressurized molten solder to an opening or nozzle of a wave soldering nozzle assembly, generally designated 36. As described in more detail below, the wave soldering nozzle assembly 36 is configured to transport the molten solder to the bottom of the printed circuit board 12 and enable a smooth flow of the solder back to the reservoir 32. Specifically, the wave soldering nozzle assembly 36 is capable of adjusting the height and width of the solder wave when performing a wave soldering operation.

[0019] The wave soldering station 24 further includes a pump impeller 38 positioned within the reservoir 32 of the solder pot 30 adjacent to the inlet provided in the flow conduit 34. The pump impeller 38 pressurizes the molten solder within the reservoir 32 and pumps the molten solder vertically within the reservoir to the wave soldering nozzle assembly 36. In one embodiment, the pump impeller 38 is a centrifugal pump that is suitably sized to pump the molten solder to the nozzle of the wave soldering nozzle assembly 36. The wave soldering nozzle assembly 36 is configured to generate the solder wave provided for attaching components onto the circuit board 12 in the methods described herein and to optimize dwell time during processing.

[0020] exit wing 5-7, the wave solder nozzle assembly 36 includes a nozzle core frame having two end walls 40, 42 and first and second longitudinal side walls 44, 46 extending between the end walls. As shown, the nozzle core frame may further include a number of cross support elements, indicated at 48, extending between the first and second longitudinal side walls 44, 46. The nozzle core frame also directs solder flow through a nozzle defined between the first and second longitudinal side walls.

[0021] The nozzle assembly 36 further includes an exit wing 50 for controlling the solder flow on the rear of the nozzle of the solder wave generated by the wave soldering machine 10. The exit wing 50 is hingedly secured to the second longitudinal sidewall 46 of the nozzle core frame by a hinge 52 to enable adjustment of the flow of the solder wave exiting the nozzle of the nozzle core frame. The exit wing 50 is rotatable about the hinge 52 by an actuator 54 via a linkage. The actuator 54 is sometimes referred to in this disclosure as a first actuator or an exit wing actuator. As described in more detail below, the position of the exit wing 50 relative to the nozzle core frame can be controlled in real time by controlling the longitudinal displacement of an actuator arm 56 of the actuator 54; therefore, the flow of the solder wave on the rear of the nozzle is decreased or increased by raising and lowering the exit wing, respectively.

[0022] The actuator 54 is secured to the solder pot 30 by an actuator support frame 58, which is secured to the sidewall of the solder pot 30 by suitable fasteners, such as bolts. Alternatively, the actuator support frame 58 can be secured to the solder pot 30 by other methods, such as welding or rivets. As shown, the actuator 54 is secured to the actuator support frame 58, which is configured to rigidly support the actuator relative to the solder pot 30. The actuator 54 is positioned adjacent to the wave solder nozzle assembly 36 and forms part of an assembly for adjusting the position of the exit wings 50 of the wave solder nozzle assembly 36 relative to the nozzle core frame via a linkage coupled to the exit wings and the actuator. The actuator 54 includes an actuator arm 56 coupled to the linkage by an actuator block 60. The linkage is described in more detail below.

[0023] In one embodiment, the actuator 54 is a linear actuator, such that the actuator arm 56 moves longitudinally. The actuator block 60 connects the actuator arm 56 to the connecting link 62 of the linkage, transmitting motion from the actuator arm to the connecting link. Thus, longitudinal movement of the actuator arm 56 causes the actuator block 60 and connecting link 62 to move longitudinally in the same direction as the actuator arm. In some embodiments, the actuator 54 and connecting link 62 are oriented such that the actuator arm moves the connecting link horizontally. In certain embodiments, the actuator 54 comprises an electromechanical actuator that provides movement to adjust the position of the exit vane 50. The actuator 54 is driven by computerized machine software (supported by the controller 26) and incorporates an encoder that can relay position instructions to the machine software. Via the controller 26, the actuator 54 can be controlled in real time to achieve a desired position of the exit vane 50. The controller 26 is in communication with the actuator 54 and is configured to cause the actuator to adjust the position of the exit vane 50 during operation of the wave soldering machine 10. And, the actuator 54 is configured to receive commands from the controller 26 that cause the actuator 54 to adjust the position of the exit vanes 50 during operation of the wave soldering machine 10 .

[0024] In one embodiment, the outlet vane 50 includes a first end coupled to the nozzle core frame second longitudinal sidewall 46 by a hinge 52 and a second end coupled to an actuator 54 via a rotational link 64 of a linkage such that the actuator can rotate the second end of the outlet vane about the hinge at the first end of the outlet vane. Rotating the outlet vane 50 about the hinge 52 changes the flow of a solder wave passing over the outlet vane. In particular, rotating the outlet vane 50 so that the second end of the outlet vane moves upward to a raised position decreases the flow of the solder wave over the outlet vane, and rotating the outlet vane so that the second end of the outlet vane moves downward to a lowered position increases the flow of the solder wave over the outlet vane.

[0025] As described above, the linkage allows the actuator 54 to adjust the position of the outlet vane 50 relative to the nozzle core frame. In particular, the linkage allows the actuator arm 56 of the actuator 54 to move longitudinally to adjust the angle of the top surface of the outlet vane 50 relative to the horizontal. In one embodiment, the linkage includes a rotation link 64, a crossbar 66, and a connecting link 62. The rotation link 64 is coupled to the second end of the outlet vane 50 by the crossbar 66, and the crossbar 66 is coupled to the actuator block 60 by the connecting link 62.

[0026] The rotation link 64 has a first end rotatably coupled to the second end of the outlet vane 50 and a second end rotatably coupled to the crossbar 66. The crossbar 66 extends perpendicular to the rotation link 64. The connecting link 62 has a first end coupled to the crossbar 66 and a second end coupled to the actuator block 60. The connecting link 62 extends perpendicular to the crossbar 66 and parallel to the actuator arm 56. When the upper surface of the outlet vane 50 extends substantially horizontally, the crossbar 66 is located below the outlet vane and longitudinally between the first end of the outlet vane and the second end of the outlet vane.

[0027] Longitudinal displacement of the actuator arm 56 causes the exit vane 50 to rotate about the hinge 52. The axial direction of the actuator arm 56 is parallel to the axial direction of the connecting link 62. Thus, the actuator arm 56 is configured to move the connecting link 62 horizontally along the axis of the direction of the actuator arm 56. Because the crossbar 66 is coupled to the connecting link 62, extension or contraction of the actuator arm 56 results in translation of the crossbar. Because the rotation link 64 is rotatably coupled to the crossbar 66 and secures the actuator 54 and the wave solder assembly 36 to the solder pot 30, this translation of the crossbar results in rotation of the exit vane 50.

[0028] 8 and 9, the actuator arm 56 is shown in an extended position in FIG. 8 and in a retracted position in FIG. 9. The second end of the exit vane 50 is shown lower (in a lowered position) in FIG. 8 than in FIG. 9 (in a raised position). A back gate 68 is secured to the second end of the exit vane 50. The controller 26 is configured to adjust the orientation of the exit vane 50 to vary the flow of solder on the back gate 68 of the exit vane. The controller 26 is configured to achieve optimal soldering characteristics of the wave nozzle assembly 36. Optimal soldering characteristics are achieved when there is no flow on the back gate 68 when the conveyor 16 is not carrying components to be soldered, such as PCBs, onto the wave solder assembly 36. However, when a PCB carried by the conveyor 16 enters the solder wave, solder begins to flow on the back gate 68 at a speed equal to the speed of the PCB along the conveyor 16. When the PCB exits the wave, solder flow on the back gate again stops.

[0029] Although the above description of solder flow relates to a PCB being carried by the conveyor 16, similar solder flow occurs when other components to be soldered are carried by the conveyor 16 over the wave solder nozzle assembly 36.

[0030] The orientations of the outlet vanes 50 shown in Figures 8 and 9 are just two example orientations of the outlet vanes 50. The rotation range of the outlet vanes 50 can be selected according to desired performance parameters of the system, such as the desired wave height range. In various embodiments, the rotation range of the outlet vanes 50 can extend beyond the orientations shown in Figures 8 and 9.

[0031] throttle gate 5-7 , the wave soldering nozzle assembly 36 further includes an elongated solder distribution baffle 70 secured to the first longitudinal sidewall 44 of the nozzle core frame. The solder distribution baffle 70 is secured to the first longitudinal sidewall 44 with screws, for example, through openings located on the input side of the baffle. In one embodiment, one side of the solder distribution baffle 70, the input side, is secured to or integrally formed with the first longitudinal sidewall 44, and the other side of the solder distribution baffle, the output side, is secured to or integrally formed with the second longitudinal sidewall 46. In one embodiment, the solder distribution baffle 70 includes a pattern of elongated openings to allow molten solder to flow through the body of the solder distribution baffle.

[0032] The wave soldering nozzle assembly 36 further includes a throttle gate 72 hingedly secured to the end walls 40, 42 of the nozzle core frame. As shown, the throttle gate 72 is secured to the nozzle core frame on the input side of the wave soldering nozzle assembly 36 and is configured to selectively block a portion of the solder distribution baffle 70 to reduce the amount of solder entering the solder distribution baffle. As shown, the throttle gate 72 is located on the input side of the nozzle assembly, although it is understood that it may be positioned elsewhere, such as on the mid or output side. The throttle gate 72 is coupled to a movement mechanism, generally designated 74, which is coupled to an actuator 76 for moving the throttle gate 72 between an open position and a closed position. The actuator 76 may be referred to in this disclosure as a second actuator or a throttle gate actuator.

[0033] Specifically, the throttle gate 72 comprises one or more plates disposed along the length of the solder distribution baffle 70. In one embodiment, a single plate is sized to block or otherwise prevent solder flow through openings in the solder distribution baffle along the length of the solder distribution baffle. The throttle gate 72 is hingedly secured to the nozzle core frame end walls 40, 42 by a hinge pin 78. As best shown in FIG. 5 , an end of the hinge pin 78 extends through an opening in each of the nozzle core frame end walls 42. The hinge pin 78 is fixedly secured to an arm 80 having an outwardly extending pin 82. This configuration is such that rotating the throttle gate 72 causes the arm 80 to rotate about the axis of the hinge pin 78. The other end of the hinge pin may or may not include a similar arm.

[0034] The movement mechanism 74 is a generally U-shaped structure having a front wall 84 facing the second longitudinal sidewall 46 of the nozzle core frame and two side walls 86, 88 facing the respective end walls 40, 42 of the nozzle core frame. The movement mechanism 74 is designed to move laterally (horizontally) relative to the nozzle core frame. The front wall 84 includes an opening configured to receive a connecting link 62 coupled to the outlet vane actuator 54. The movement mechanism 74 is coupled to a throttle gate actuator 76 configured to provide lateral movement of the movement mechanism. The movement mechanism 74 can be controlled in real time by controlling the longitudinal displacement of an actuator arm 90 of the actuator 76 and, therefore, the movement of the throttle gate 72 between the open and closed positions. Similar to the outlet vane actuator 54, the actuator is secured to the solder pot 30 by an actuator support frame 58. The throttle gate actuator 76 is positioned adjacent to the outlet vane actuator 54 and forms part of an assembly for adjusting the position of the throttle gate 72. The actuator 76 includes an actuator arm 90 coupled to a linkage by an actuator block 92 .

[0035] Like the outlet vane actuator 54, the throttle gate actuator 76 is a linear actuator, thus the actuator arm 90 moves longitudinally. An actuator block 92 connects the actuator arm 90 to a connecting link 94 of the linkage, transferring motion from the actuator arm to the connecting link. The other end of the connecting link 94 is fixed to the front wall 84 of the movement mechanism 74. Thus, longitudinal movement of the actuator arm 90 causes the actuator block 92 and connecting link 94 to move longitudinally in the same direction as the actuator arm. In some embodiments, the actuator 76 and connecting link 94 are oriented such that the actuator arm 90 moves the connecting link horizontally. In certain embodiments, the actuator 76 includes an electromechanical actuator that provides motion to adjust the position of the throttle gate 72. The actuator 76 is driven by computer-controlled machine software (supported by the controller 26) and incorporates an encoder that can relay position instructions to the machine software. Via the controller 26, the actuator 76 can be controlled in real time to achieve a desired position of the throttle gate 72. The controller 26 is in communication with the actuator 76 and is configured to cause the actuator to adjust the position of the throttle gate 72 during operation of the wave soldering machine 10. The actuator 76 is then configured to receive commands from the controller 26 that cause the actuator 76 to adjust the position of the throttle gate 72 during operation of the wave soldering machine 10.

[0036] The side wall 88 of the movement mechanism 74 is coupled to the arm 80 of the throttle gate 72. As best shown in FIG. 5 , the outwardly extending pin 82 extends through a slot 96 formed in the side wall 88. As mentioned above, the other side wall 86 may or may not be similarly configured. This configuration is such that lateral (horizontal) movement of the movement mechanism 74 moves the throttle gate 72 between its open and closed positions. Two slots are further formed in each side wall 86, 88, each receiving a pin to guide movement of the movement mechanism 74 relative to the wave solder nozzle assembly 36. A connecting link 94 is fixed to the front wall 84 of the movement mechanism 74. Thus, when the connecting link 94 is extended by the throttle gate actuator 76, the front wall 84 of the movement mechanism 74 is positioned against the second longitudinal side wall 46 of the nozzle core frame. In this position, the throttle gate 72 is in an open position. When the connecting link 94 is retracted by the throttle gate actuator 76, the front wall 84 of the moving mechanism 74 is spaced from the second longitudinal side wall 46 of the nozzle core frame. In this position, the throttle gate 72 is in a closed position.

[0037] Longitudinal displacement of the actuator arm 90 causes the throttle gate 72 to rotate about the hinge pin 78. The axial direction of the actuator arm 90 is parallel to the axial direction of the connecting link 94. Thus, the actuator arm 90 is configured to move the connecting link 94 horizontally along the axis of the actuator arm's direction. Because the front wall 84 of the movement mechanism 74 is coupled to the connecting link 94, extension or contraction of the actuator arm 90 causes the movement mechanism to translate.

[0038] 10 and 11, the actuator arm 90 associated with the throttle gate actuator 76 is shown in a retracted position in FIG. 10 and in an extended position in FIG. 11. With further reference to FIGS. 12 and 13, FIGS. 11 and 12 show the throttle gate 72 in an open position. FIGS. 10 and 13 show the throttle gate 72 in a closed position. The controller 26 is configured to adjust the position of the throttle gate 72 to control the flow of solder through the solder distribution baffle 70, thereby optimizing solder contact time. The controller 26 is configured to achieve optimal soldering characteristics for the wave nozzle assembly 36. As previously mentioned, controlling the throttle gate 72, in addition to controlling the operation of the outlet vanes 50, helps to achieve optimal soldering characteristics.

[0039] As described above, the first actuator 54 is configured to control the exit vane 50 to control the flow of solder over the exit vane back gate 68 and optimize solder joint formation. This feature reduces solder bridging defects during the wave soldering process. The second actuator 76 is configured to control the throttle gate 72 to control the flow through the solder distribution baffle 70 and optimize solder contact time. This feature reduces copper melting during the wave soldering process.

[0040] 14, extending the second actuator 76 rotates the throttle gate 72 to an open position. Opening the throttle gate 72 increases solder flow, indicated by arrow A, through the solder distribution baffle 70, thereby extending the contact time of the printed circuit board moving over the solder wave. Additionally, retracting the first actuator 54 pivots the exit vanes 50 to a raised position. The exit vanes 50 rise due to the increased solder flow caused by the open throttle gate 72.

[0041] 15, retracting the second actuator 76 rotates the throttle gate 72 to a closed position. Closing the throttle gate 72 reduces solder flow, indicated by arrow B, through the solder distribution baffle 70, thereby reducing the contact time of the printed circuit board moving over the solder wave. Additionally, extending the first actuator 54 pivots the exit vanes 50 to a lowered position. The exit vanes 50 lower due to the reduced solder flow caused by the closed throttle gate 72.

[0042] Referring to FIG. 16, which shows the throttle gate 72 in the open position and the exit vanes 50 in the raised position, as shown in FIG. 14, a printed circuit board is shown moving over the solder wave along direction C. As discussed above, the printed circuit board 12 moves over the solder wave over a maximum contact length D. The throttle gate 72 and exit vanes 50 are controlled (by the controller 26) to match the speed of the printed circuit board (Vpcb) to the speed of the solder flow (Vs). As discussed above, when these two speeds (Vpcb and Vs) are equal, the likelihood of soldering defects, particularly solder bridging, is significantly reduced. If the speeds are not optimized, the resulting defects may require rework or scrap.

[0043] Referring to Figure 17, which shows the throttle gate 72 in the closed position and the exit vanes 50 in the lowered position shown in Figure 15, the printed circuit board 12 is shown moving over the solder wave along direction E. As discussed above, the printed circuit board 12 moves over the solder wave over a minimum contact length F. The throttle gate 72 and exit vanes 50 are controlled (by the controller 26) to match the speed of the printed circuit board (Vpcb) to the speed of the solder flow (Vs).

[0044] In some embodiments, the wave solder nozzle assembly 36 further comprises a dross damper secured to the nozzle frame and configured to reduce turbulence as the solder returns to the reservoir 32, thereby reducing solder balls that may form in the reservoir. One or more nitrogen tubes may be provided to create an inert atmosphere during the wave soldering process.

[0045] In some embodiments, a shroud extends around the wave solder nozzle assembly 36. In some embodiments, the shroud surrounds the wave solder nozzle assembly and creates a substantially gas-impermeable inert atmosphere surrounding the solder wave. In some embodiments, the shroud is substantially nitrogen-impermeable. The shroud includes two sealed openings through which the connecting links extend. Each sealed opening has an inner surface that substantially sealingly engages the outer surface of a respective one of the connecting links. Each connecting link has a substantially constant cross-section over the portion of the connecting link that passes through the sealed opening, allowing the connecting links to substantially form a gas-impermeable seal with the inner surface of the respective sealed opening. In some embodiments, the inner surface of each sealed opening is annular, and the outer surface of each connecting link has a matching circular profile such that the inner surface substantially sealingly engages the outer surface as each connecting link moves along the axial direction of the connecting link through the sealed opening.

[0046] The present disclosure also provides a method for adjusting the flow of a solder wave in a wave solder nozzle assembly of a wave soldering machine. In some embodiments, the method can be performed using the wave soldering station 24 described above or a wave soldering machine 10 equipped with the wave soldering station 24.

[0047] In some embodiments, the method includes delivering solder material to a wave solder nozzle assembly 36 comprising a nozzle core frame and an exit wing hingedly attached to the nozzle core frame, adjusting the flow of the solder wave by causing a linear actuator connected to the exit wing to adjust the orientation of the exit wing relative to the nozzle core frame, and performing a wave soldering operation on a printed circuit board.

[0048] In some embodiments, adjusting the solder wave flow is achieved by rotating the exit vane relative to the nozzle core frame by a linkage coupled to the linear actuator and the exit vane. In some embodiments, the linkage comprises a connecting link and a rotating link, and the method includes causing translation of the connecting link along a motion axis of the linear actuator to cause rotation of the rotating link.

[0049] In some embodiments, the method includes creating a substantially gas-impermeable atmosphere above the solder wave. In some embodiments, this is accomplished by a shroud surrounding the wave soldering station 24. The shroud includes at least one sealed opening through which each connecting link of the linkage extends. In some embodiments, the shroud includes two sealed openings. A first one of the connecting links extends through a first one of the sealed openings, and a second one of the connecting links extends through a second one of the sealed openings. An inner surface of each sealed opening is in substantial sealing engagement with an outer surface of a respective connecting link.

[0050] In some embodiments of the method, the actuator is coupled to a controller 26 that controls the movement of the linear actuator.

[0051] As used in this disclosure, "solder wave height" describes the vertical dimension of the solder wave.

[0052] Various controllers can perform the various operations discussed above. For example, as discussed above, a controller such as controller 26 can control, among other operations, components of the wave soldering machine 10, including the wave soldering station 24. Using data stored in associated memory and / or storage, the controller can execute one or more instructions stored on one or more non-transitory computer-readable media that the controller may comprise and / or be coupled to, which may result in the data being manipulated. In some examples, the controller can include one or more processors or other types of controllers. In one example, the controller is or includes at least one processor. In another example, the controller performs at least some of the operations discussed above using application-specific integrated circuits tailored to perform specific operations in addition to, or instead of, a general-purpose processor. As illustrated by these examples, examples according to the present disclosure can perform the operations described in this disclosure using many specific combinations of hardware and software, and the present disclosure is not limited to any particular combination of hardware and software components. Examples of the present disclosure may include computer program products configured to perform the methods, processes, and / or operations discussed above. The computer program product may be or may include one or more controllers and / or processors configured to execute instructions for performing the methods, processes, and / or actions discussed above.

[0053] According to embodiments, the solder flow through the nozzle can be controlled to reduce or even prevent dross recirculation through the nozzle. Dross is reduced by reducing the width of the solder wave. According to embodiments, the width of the solder wave can be reduced.

[0054] In some embodiments, the wave soldering nozzle assembly further comprises a dross box secured to the nozzle frame and configured to further reduce solder balls that may form in the reservoir by reducing turbulence as the solder returns to the reservoir.

[0055] In some embodiments, one or more nitrogen tubes may be provided to create an inert atmosphere during the wave soldering process.

[0056] In some embodiments, the minimum and maximum contact can be varied.

[0057] As used in this disclosure, "solder wave width" describes the cross-sectional dimension of the actual solder wave, and "contact length" describes the distance on the PCB that is in contact with the wave at any given time. As used in this disclosure, the term "length" refers to the contact length parallel to the direction of PCB movement. As used in this disclosure, the term "height" refers to the height of the solder wave above the solder distribution baffle.

[0058] Having thus described several aspects of at least one embodiment of this disclosure, it should be understood that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of this disclosure. Accordingly, the foregoing description and drawings are by way of example only.

Claims

1. 1. A wave soldering machine for performing a wave soldering operation on a printed circuit board, comprising: Housing and a conveyor coupled to the housing, the conveyor configured to deliver a printed circuit board through the housing; a wave soldering station coupled to the housing, a solder pot having a reservoir of solder material; a flow conduit positioned within the reservoir of the solder pot; a wave soldering nozzle assembly coupled to the flow conduit, the wave soldering nozzle assembly including: a solder distribution baffle configured to create a solder wave; a throttle gate coupled to the flow conduit, the throttle gate configured to move from an open position to allow complete flow of solder through the solder distribution baffle and from a closed position to block a portion of the solder flow through the solder distribution baffle; and an exit vane coupled to the flow conduit, the exit vane configured to move from a lowered position to allow increased solder flow and from a raised position to decrease solder flow; a wave soldering station comprising: a controller coupled to the wave soldering station for controlling movement of the throttle gate and the exit vanes to control solder flow; A wave soldering machine comprising:

2. 10. The wave soldering machine of claim 1, wherein the wave soldering nozzle assembly further comprises a core frame supported by the flow conduit, the core frame configured to support the solder distribution baffle.

3. 3. The wave soldering machine of claim 2, wherein the exit wings are hingedly rotatable relative to the nozzle core frame to move the exit wings between the lowered position and the raised position.

4. 4. The wave soldering machine of claim 3, wherein the wave solder nozzle assembly further comprises an exit wing actuator connected to the exit wing and coupled to the controller, the exit wing actuator configured to adjust the position of the exit wing between the lowered position and the raised position.

5. 5. The wave soldering machine of claim 4, wherein the exit vane actuator is connected to the exit vane by a linkage, the linkage comprising at least one rotation link having a first end rotatably coupled to an end of the exit vane and a second end rotatably coupled to an actuator arm of the exit vane actuator.

6. 6. The wave soldering machine of claim 5, wherein the linkage further comprises: a crossbar extending perpendicular to the at least one rotation link, the crossbar being rotatably coupled to the at least one rotation link; and at least one connecting link coupling the crossbar to the actuator arm, the at least one connecting link extending perpendicular to the crossbar, the at least one connecting link being connected to the actuator arm by an actuator block.

7. 5. The wave soldering machine of claim 4, wherein the throttle gate comprises a plate and a hinge pin hingedly secured to the nozzle core frame.

8. 8. The wave soldering machine of claim 7, wherein the wave soldering nozzle assembly further comprises a throttle gate actuator configured to move the throttle gate between the open position and the closed position.

9. 9. The wave soldering machine of claim 8, wherein the wave soldering nozzle assembly further comprises a link fixed to a movement mechanism, the movement mechanism being coupled to the throttle plate.

10. The wave soldering machine of claim 9 , wherein the movement mechanism is coupled to an arm fixed to the hinge pin of the throttle gate.

11. 1. A wave soldering station of a wave soldering machine configured to perform a wave soldering operation on a printed circuit board, comprising: a solder pot having a reservoir of solder material; a flow conduit positioned within the reservoir of the solder pot; a wave soldering nozzle assembly coupled to the flow conduit, the wave soldering nozzle assembly including: a solder distribution baffle configured to create a solder wave; a throttle gate coupled to the flow conduit, the throttle gate configured to move from an open position to allow complete flow of solder through the solder distribution baffle and from a closed position to block a portion of the solder flow through the solder distribution baffle; and an exit vane coupled to the flow conduit, the exit vane configured to move from a lowered position to allow increased solder flow and from a raised position to decrease solder flow; Equipped with a controller coupled to the wave soldering station configured to control movement of the throttle gate and the exit vanes to control solder flow; Wave soldering station.

12. The wave soldering station of claim 11 , wherein the wave soldering nozzle assembly further comprises a core frame supported by the flow conduit, the core frame configured to support the solder distribution baffle.

13. 13. The wave soldering station of claim 12, wherein the exit wings are hingedly rotatable relative to the nozzle core frame to move the exit wings between the lowered position and the raised position.

14. 14. The wave soldering station of claim 13, wherein the wave solder nozzle assembly further comprises an outlet wing actuator connected to the outlet wing and coupled to the controller, the outlet wing actuator configured to adjust the position of the outlet wing between the lowered position and the raised position.

15. 15. The wave soldering station of claim 14, wherein the exit vane actuator is connected to the exit vane by a linkage comprising at least one rotation link having a first end rotatably coupled to an end of the exit vane and a second end rotatably coupled to an actuator arm of the exit vane actuator.

16. 16. The wave soldering station of claim 15, wherein the linkage further comprises: a crossbar extending perpendicular to the at least one rotating link, the crossbar being rotatably coupled to the at least one rotating link; and at least one connecting link coupling the crossbar to the actuator arm, the at least one connecting link extending perpendicular to the crossbar, the at least one connecting link being connected to the actuator arm by an actuator block.

17. The wave soldering station of claim 14 , wherein the throttle gate comprises a plate and a hinge pin hingedly secured to the nozzle core frame.

18. 18. The wave soldering station of claim 17, wherein the wave soldering nozzle assembly further comprises a throttle gate actuator configured to move the throttle gate between the open position and the closed position.

19. 20. The wave soldering station of claim 18, wherein the wave soldering nozzle assembly further comprises a link secured to a movement mechanism, the movement mechanism being coupled to the throttle plate.

20. 20. The wave soldering station of claim 19, wherein the movement mechanism is coupled to an arm secured to the hinge pin of the throttle gate.

21. 1. A method for adjusting a solder wave flow in a wave solder nozzle assembly of a wave soldering machine, comprising: delivering solder material to a wave solder nozzle assembly having a solder distribution baffle configured to produce a solder wave; a throttle gate coupled to the flow conduit, the throttle gate configured to move from an open position to allow complete flow of solder through the solder distribution baffle and from a closed position to block a portion of the solder flow through the solder distribution baffle; and an exit vane coupled to the flow conduit, the exit vane configured to move from a lowered position to allow increased solder flow and from a raised position to decrease solder flow; adjusting the solder wave flow with a throttle gate actuator connected to the throttle gate for adjusting a position of the throttle gate and an outlet vane actuator coupled to the outlet vane for adjusting a position of the outlet vane relative to the nozzle core frame; performing a wave soldering operation on the printed circuit board; A method comprising:

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