System and method for combined wave soldering flow design

Abstract

A wave soldering station includes a solder tank having a solder reservoir, a flow conduit disposed in the reservoir of the solder tank, and a wave soldering nozzle assembly coupled to the flow conduit. The wave soldering nozzle assembly has: a solder distribution baffle configured to generate solder waves; a throttle gate coupled to the flow conduit and configured to move from an open position allowing the flow of solder to completely pass through the solder dispensing baffle and a closed position inhibiting a portion of the flow of solder from passing through the solder dispensing baffle; and an outlet wing plate coupled to the flow conduit and configured to move from a lowered position that increases the flow of solder and from a raised position that decreases the flow of solder. A controller is configured to control movement of the throttle gate and the outlet flap to control solder flow.

Description

Background of the Invention 1. Technical Field

[0001] The present disclosure relates generally to apparatus and methods for manufacturing printed circuit boards and for aiding in the process of soldering metal to integrated circuit boards, and more particularly to a wave soldering machine and related methods having a wave soldering nozzle assembly configured to control the flow of solder. 2. Background Technology

[0002] In the manufacture of printed circuit boards, electronic components can be mounted to the printed circuit board using a process known as "wave soldering." In a typical wave soldering machine, a printed circuit board (sometimes referred to as a "PCB") is moved on an inclined path by a conveyor, passing through a fluxing station, a preheating station, and finally a wave soldering station. At the wave soldering station, a wave of solder (via a pump) is forced upward through a wave soldering nozzle and into contact with the portion of the printed circuit board to be soldered.

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

[0004] One aspect of the present disclosure relates to a wave soldering machine for performing a wave soldering operation on a printed circuit board. In one embodiment, the wave soldering machine includes a housing and a conveyor coupled to the housing. The conveyor is configured to transport the printed circuit board through the housing. The wave soldering machine further includes a wave soldering station coupled to the housing. The wave soldering station includes a solder tank having a solder reservoir, a flow conduit disposed in the reservoir of the solder tank, and a wave soldering nozzle assembly coupled to the flow conduit. The wave soldering nozzle assembly includes: a solder dispensing baffle configured to generate a solder wave; a throttle gate coupled to the flow conduit and configured to move from an open position and a closed position, wherein the open position allows the solder flow to completely pass through the solder dispensing baffle and the closed position prohibits a portion of the solder flow from passing through the solder dispensing baffle; and an outlet flap coupled to the flow conduit and configured to move from a lowered position to increase the solder flow rate and from a raised position to reduce the solder flow rate. The wave soldering machine further includes a controller coupled to the wave soldering station to control movement of the throttle gate and the outlet vane to control solder flow.

[0005] Embodiments of the wave soldering machine may further include configuring the wave soldering nozzle assembly to have a core frame supported by a flow conduit. The core frame may be configured to support a solder dispensing baffle. The outlet flap may rotate about a hinge relative to the nozzle core frame to move the outlet flap between a lowered position and a raised position. The wave soldering nozzle assembly may further include an outlet flap actuator connected to the outlet flap and coupled to a controller. The outlet flap actuator may be configured to adjust the position of the outlet flap between a lowered position and a raised position. The outlet flap actuator may be connected to the outlet flap via a linkage mechanism comprising at least one rotating link having a first end rotatably coupled to one end of the outlet flap and a second end rotatably coupled to an actuator arm of the outlet flap actuator. The linkage mechanism may further include: a crossbar extending perpendicular to the at least one rotating link and rotatably coupled to the at least one rotating link; and at least one connecting rod connecting the crossbar to the actuator arm and extending perpendicular to the crossbar. The at least one connecting rod may be connected to the actuator arm via an actuator segment. 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 linkage secured to a motion mechanism coupled to the throttle plate. The motion 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 a wave soldering operation on a printed circuit board. In one embodiment, the wave soldering station includes a solder tank having a solder reservoir, a flow conduit disposed in the reservoir of the solder tank, and a wave soldering nozzle assembly coupled to the flow conduit. The wave soldering nozzle assembly includes: a solder dispensing baffle configured to generate a solder wave; a throttle gate coupled to the flow conduit and configured to move from an open position and a closed position, wherein the open position allows the solder flow to completely pass through the solder dispensing baffle and the closed position inhibits a portion of the solder flow from passing through the solder dispensing baffle; and an outlet flap coupled to the flow conduit and configured to move from a lowered position that allows an increase in solder flow and from a raised position that reduces the solder flow. A controller coupled to the wave soldering station is configured to control the movement of the throttle gate and the outlet flap to control the solder flow.

[0007] Embodiments of the wave soldering station may further include configuring the wave soldering nozzle assembly to include a core frame supported by a flow conduit. The core frame may be configured to support a solder dispensing baffle. The outlet flap may rotate about a hinge relative to the nozzle core frame to move the outlet flap between a lowered position and a raised position. The wave soldering nozzle assembly may further include an outlet flap actuator connected to the outlet flap and coupled to a controller. The outlet flap actuator may be configured to adjust the position of the outlet flap between a lowered position and a raised position. The outlet flap actuator may be connected to the outlet flap via a linkage mechanism comprising at least one rotating link having a first end rotatably coupled to one end of the outlet flap and a second end rotatably coupled to an actuator arm of the outlet flap actuator. The linkage mechanism may further include: a crossbar extending perpendicular to the at least one rotating link and rotatably coupled to the at least one rotating link; and at least one connecting rod connecting the crossbar to the actuator arm and extending perpendicular to the crossbar. The at least one connecting rod may be connected to the actuator arm via an actuator segment. 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 linkage secured to a motion mechanism coupled to the throttle plate. The motion mechanism may be coupled to an arm secured to the hinge pin of the throttle gate.

[0008] Another aspect of the present disclosure relates to a method for regulating the flow of a solder wave of a wave soldering nozzle assembly of a wave soldering machine. In one embodiment, the method includes: delivering solder to a wave soldering nozzle assembly, the wave soldering nozzle assembly comprising: a solder dispensing baffle configured to generate a solder wave; a throttle gate coupled to a flow conduit and configured to move between an open position allowing solder flow to fully pass through the solder dispensing baffle and a closed position inhibiting a portion of the solder flow from passing through the solder dispensing baffle; and an outlet vane coupled to the flow conduit and configured to move between a lowered position for increasing solder flow and a raised position for reducing solder flow; regulating the flow of the solder wave by adjusting a position of the throttle gate via a throttle gate actuator coupled to the throttle gate and a position of the outlet vane relative to a nozzle core frame via an outlet vane actuator coupled to the outlet vane; and performing a wave soldering operation on a printed circuit board. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0010] Figure 1 It is a three-dimensional diagram of a wave soldering machine;

[0011] Figure 2 is a side view of a wave soldering machine with the outer cover removed to expose the internal components of the wave soldering machine;

[0012] Figure 3 is a perspective view of a wave soldering station according to an embodiment of the present disclosure;

[0013] Figure 4 is a cross-sectional view of a wave soldering station with the wave soldered components separated from the solder pot of the wave soldering station;

[0014] Figure 5 It is a three-dimensional diagram of a wave soldered assembly;

[0015] Figure 6 Here is another perspective view of a wave soldered assembly;

[0016] Figure 7 It is an exploded perspective view of the wave soldering assembly;

[0017] Figure 8 is a side view of a wave soldered assembly showing the exit flap in a lowered position;

[0018] Figure 9 is a side view of a wave soldering assembly showing the exit flap in a raised position;

[0019] Figure 10 is a side view of a wave soldering assembly showing the throttle gate in the closed position;

[0020] Figure 11 is a side view of a wave soldering assembly showing the throttle gate in the open position;

[0021] Figure 12 is an enlarged cross-sectional view of the outlet vane in a raised position and the throttle gate in an open position;

[0022] Figure 13 is an enlarged cross-sectional view of the outlet vane in the lowered position and the throttle gate in the closed position;

[0023] Figure 14 is similar to Figure 12 a cross-sectional view showing solder flow through a wave soldered assembly;

[0024] Figure 15 is similar to Figure 13 a cross-sectional view showing solder flow through a wave soldered assembly;

[0025] Figure 16 is similar to Figure 12 and Figure 14 a cross-sectional view showing solder flowing through a wave soldering assembly and a printed circuit board passing through the solder wave; and

[0026] Figure 17 is similar to Figure 13 and Figure 15 A cross-sectional view showing solder flowing through a wave soldered assembly and a printed circuit board passing through the solder wave. DETAILED DESCRIPTION

[0027] The present disclosure is not limited in its application to the details of the construction and arrangement of the components set forth in the following description or shown in the accompanying drawings. The present disclosure can have other embodiments and can be put into practice or implemented in various ways. Likewise, the wording and terminology used herein are for descriptive purposes and should not be considered as limiting. The use of "comprises," "comprising," "having," "containing," "involving," and variations thereof herein is intended to encompass the items listed thereafter and their equivalents as well as other items.

[0028] Embodiments of the present disclosure relate to controlling the flow of molten solder over a nozzle in order to optimize the flow of a solder wave. One objective is to provide the ability to adjust the contact of a printed circuit board with the solder wave. Another objective is to adjust the solder flow at the exit of the solder wave to optimize soldering characteristics. Another objective is to automate this adjustment and allow computer control so that adjustments are made based on the product being processed without the need for human intervention.

[0029] For demonstration purposes and reference Figure 1Embodiments of the present disclosure will now be described with reference to a wave soldering machine, generally designated 10, for applying solder to printed circuit boards 12. The wave soldering machine 10 is one of several machines in a printed circuit board production / assembly line. As shown, the wave soldering machine 10 includes a housing or frame 14 adapted to house the various components of the machine. The arrangement allows a conveyor 16 to transport printed circuit boards to be processed by the wave soldering machine 10. Upon entering the wave soldering machine 10, each printed circuit board 12 travels along the conveyor 16 along an inclined path (e.g., at an angle of six degrees relative to the horizontal) through a channel 18 to condition the printed circuit board for wave soldering. The channel includes a fluxing station, generally designated 20, and a preheating station, generally designated 22. Once conditioned (i.e., heated), the printed circuit boards 12 proceed to a wave soldering station, generally designated 24, for solder to be applied to the printed circuit board. The controller 26 is configured 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 well-known manner.

[0030] refer to Figure 2 The fluxing station 20 is configured to apply flux to the printed circuit board as the printed circuit board travels through the wave soldering machine 10 on the conveyor 16. The preheating station includes several preheaters (e.g., preheaters 22a, 22b, and 22c) that are designed to incrementally increase the temperature of the printed circuit board as the printed circuit board travels through the channel 18 along the conveyor 16 to prepare the printed circuit board for the wave soldering process. As shown and described in more detail below, the wave soldering station 24 includes a wave soldering nozzle assembly in fluid communication with a solder reservoir. A pump is provided in the reservoir to transport molten solder from the reservoir to the wave soldering nozzle assembly. Once soldering is completed, the printed circuit board leaves the wave soldering machine 10 via the conveyor 16 and goes to another station (e.g., a pick-and-place machine) provided in the production line.

[0031] In some embodiments, the wave soldering machine 10 may further include a flux management system, generally indicated at 28, to remove volatile contaminants from the channel 18 of the wave soldering machine. Figure 2 As shown, the flux management system 28 is arranged below the preheating station 22. In one embodiment, the flux management system is supported by the housing 14 within the wave soldering machine and is in fluid communication with the channel 18. Figure 2 The flux management system 28 is configured to receive contaminated gas from the channel 18, process the gas, and return clean gas to the channel. The flux management system 28 is particularly configured to remove volatile contaminants from the gas, especially under an inert atmosphere.

[0032] Embodiments of the present disclosure involve varying the contact length (also known as "dwell time"), which is the amount of time a PCB is in contact with the solder wave. The wide variety of PCB sizes, weights, shapes, compositions, and so on, impacts the range of the process window; therefore, a "one-size-fits-all" approach to dwell time is not always the most efficient approach. A soldering process that is not effectively optimized can result in solder defects that lead to rework or scrap.

[0033] Further, embodiments of the present disclosure relate to optimizing the flow of the solder wave relative to the printed circuit board 12. When processing the printed circuit board 12, it is desirable to control the velocity of the solder flow (Vs) so that it approaches the velocity of the printed circuit board 12 as it exits the solder wave (Vpcb). When these two velocities are equal, the likelihood of solder defects, particularly solder bridging, is significantly reduced. When the velocity is not optimized, the resulting defects may require rework or scrapping.

[0034] refer to Figure 3 and Figure 4 In one embodiment, the wave soldering station 24 includes a solder pot 30 that defines a reservoir 32 configured to hold 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 will be described in greater detail below, the wave soldering nozzle assembly 36 is configured to direct the molten solder to the bottom of the printed circuit board 12 and allow the solder to flow smoothly back into 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.

[0035] The wave soldering station 24 further includes a pump impeller 38 disposed within the reservoir 32 of the solder tank 30 adjacent to an inlet disposed in the flow conduit 34. The pump impeller 38 pressurizes the molten solder in the reservoir 32 to vertically pump the molten solder within the reservoir to the wave soldering nozzle assembly 36. In one embodiment, the pump impeller 38 is a centrifugal pump that is appropriately 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 a solder wave that is provided to attach components to the circuit board 12 in the manner described herein and to optimize dwell time during processing.

[0036] outlet wing

[0037] Additional references Figures 5 to 7The wave soldering nozzle assembly 36 includes a nozzle core frame having two end walls 40, 42, a first longitudinal side wall 44 and a second longitudinal side wall 46, each extending between the end walls. As shown, the nozzle core frame may further include a plurality of transverse support members, generally designated 48, extending between the first longitudinal side wall 44 and the second longitudinal side wall 46. The nozzle core frame also directs the flow of solder through the nozzle defined between the first longitudinal side wall and the second longitudinal side wall.

[0038] The nozzle assembly 36 further includes an outlet wing 50 to control the solder flow of the solder wave generated by the wave soldering machine 10 on the rear of the nozzle. In order to allow adjustment of the flow of the solder wave leaving the nozzle of the nozzle core frame, the outlet wing 50 is hingedly fixed to the second longitudinal side wall 46 of the nozzle core frame by a hinge 52. The outlet wing 50 can be rotated about the hinge 52 via an actuator 54 via a linkage mechanism. The actuator 54 is sometimes referred to as the first actuator or the outlet wing actuator in this article. As described in more detail below, the position of the outlet wing 50 relative to the nozzle core frame can be controlled in real time by controlling the longitudinal displacement of the actuator arm 56 of the actuator 54, and the flow of the solder wave on the rear of the nozzle can be controlled to increase or decrease respectively by raising and lowering the outlet wing.

[0039] The actuator 54 is fixed to the solder pot 30 by an actuator support frame 58, which is fixed to the side wall of the solder pot 30 by suitable fasteners (e.g., bolts). Alternatively, the actuator support frame 58 can be fixed to the solder pot 30 by another method (e.g., welding or riveting). As shown, the actuator 54 is fixed to the actuator support frame 58, which is configured to firmly support the actuator relative to the solder pot 30. The actuator 54 is arranged next to the wave soldering nozzle assembly 36 and forms a part of the assembly to adjust the position of the outlet wing 50 of the wave soldering nozzle assembly 36 relative to the nozzle core frame via a linkage mechanism connected to the outlet wing and the actuator. The actuator 54 includes an actuator arm 56, which is connected to the linkage mechanism by an actuator segment 60. The linkage mechanism is described in more detail below.

[0040] In one embodiment, actuator 54 is a linear actuator, so actuator arm 56 moves in the longitudinal direction. Actuator section 60 connects actuator arm 56 to connecting rod 62 of linkage mechanism, so that motion is transferred from actuator arm to connecting rod. Therefore, the longitudinal movement of actuator arm 56 makes actuator section 60 and connecting rod 62 move in the longitudinal direction identical with actuator arm. In certain embodiments, actuator 54 and connecting rod 62 are oriented so that actuator arm moves connecting rod in the horizontal direction. In certain embodiments, actuator 54 includes an electromechanical actuator that provides motion for the position adjustment of outlet wing plate 50. Actuator 54 is driven by computer-controlled machine software (supported by controller 26) and includes an encoder, which can forward position indication to machine software. Actuator 54 can be controlled in real time via controller 26 to achieve the desired position of outlet wing plate 50. The controller 26 is in communication with the actuator 54 and is configured to cause the actuator to adjust the position of the outlet flap 50 during operation of the wave soldering machine 10. In turn, the actuator 54 is configured to receive commands from the controller 26 during operation of the wave soldering machine 10 to cause the actuator 54 to adjust the position of the outlet flap 50.

[0041] In one embodiment, the outlet flap 50 includes a first end coupled to the second longitudinal sidewall 46 of the nozzle core frame via a hinge 52 and a second end coupled to an actuator 54 via a rotating link 64 of a linkage mechanism, such that the actuator can cause the second end of the outlet flap to rotate about the hinge at the first end of the outlet flap. Rotating the outlet flap 50 about the hinge 52 changes the flow rate of the solder wave passing through the outlet flap. Specifically, rotating the outlet flap 50 so that the second end of the outlet flap moves upward to a raised position reduces the flow rate of the solder wave on the outlet flap, while rotating the outlet flap so that the second end of the outlet flap moves downward to a lowered position increases the flow rate of the solder wave on the outlet flap.

[0042] As described above, the linkage mechanism allows the actuator 54 to adjust the position of the outlet vane 50 relative to the nozzle core. Specifically, the linkage mechanism allows the actuator arm 56 of the actuator 54 to move longitudinally to adjust the angle of the upper surface of the outlet vane 50 relative to the horizontal. In one embodiment, the linkage mechanism includes a rotating link 64, a crossbar 66, and a connecting rod 62. The rotating link 64 is coupled to the second end of the outlet vane 50 via the crossbar 66, which is in turn coupled to the actuator section 60 via the connecting rod 62.

[0043] The rotating link 64 has a first end and a second end. The first end is rotatably coupled to the second end of the outlet vane 50, and the second end is rotatably coupled to the crossbar 66. The crossbar 66 extends perpendicular to the rotating link 64. The connecting rod 62 has a first end coupled to the crossbar 66 and a second end coupled to the actuator section 60. The connecting rod 62 extends perpendicular to the crossbar 66 and parallel to the actuator arm 56. When the upper surface of the outlet vane 50 extends generally horizontally, the crossbar 66 is located below the outlet vane and longitudinally between the first and second ends of the outlet vane.

[0044] Longitudinal displacement of the actuator arm 56 enables the outlet flap 50 to rotate about the hinge 52. The axial direction of the actuator arm 56 is parallel to the axial direction of the connecting rod 62. Thus, the actuator arm 56 is configured to move the connecting rod 62 in a horizontal direction along an axis of the actuator arm 56. Because the crossbar 66 is coupled to the connecting rod 62, extension or retraction of the actuator arm 56 causes the crossbar to translate. Because the rotating link 64 is rotatably coupled to the crossbar 66 and because the actuator 54 and the wave soldering assembly 36 are fixed to the solder pot 30, this translation of the crossbar causes the outlet flap 50 to rotate.

[0045] refer to Figure 8 and Figure 9 , the actuator arm 56 is shown as Figure 8 In the extended position, Figure 9 The second end of the outlet wing 50 is in the retracted position. Figure 8 is shown as Figure 9 6 (lowered position). The rear gate 68 is fixed to the second end of the outlet wing 50. The controller 26 is configured to adjust the orientation of the outlet wing 50 to change the solder flow on the rear gate 68 of the outlet wing. The controller 26 is configured to achieve optimal soldering characteristics of the wave soldering nozzle assembly 36. When the conveyor 16 is not carrying parts to be soldered (such as PCBs) on the wave soldering assembly 36, the optimal soldering characteristics are achieved when no solder flows over the rear gate 68. However, once the PCB carried by the conveyor 16 enters the solder wave, the solder begins to flow through the rear gate 68 at the same speed as the speed of the PCB along the conveyor 16. Once the PCB leaves the solder wave, the solder flow on the rear gate stops again.

[0046] Although the above description of solder flow relates to the conveyor 16 carrying PCBs, similar solder flow can occur on the wave solder nozzle assembly 36 for other parts to be soldered carried by the conveyor 16.

[0047] Figure 8 and Figure 9The orientations of the outlet vane 50 shown are only two examples of orientations of the outlet vane. The range of rotation of the outlet vane 50 can be selected based on the desired system performance parameters (e.g., the desired wave height range). In various embodiments, the range of rotation of the outlet vane 50 can be extended to Figure 8 and Figure 9 Orientations other than those shown.

[0048] Throttle gate

[0049] Return Reference Figures 5 to 7 The wave soldering nozzle assembly 36 further includes an elongated solder distribution baffle 70 secured to the first longitudinal side wall 44 of the nozzle core frame. The solder distribution baffle 70 is secured to the first longitudinal side wall 44, for example, with screws, through openings located on the loading side of the baffle. In one embodiment, one side (i.e., the loading side) of the solder distribution baffle 70 is secured to or integrally formed with the first longitudinal side wall 44, and the other side (i.e., the unloading side) of the solder distribution baffle is secured to or integrally formed with the second longitudinal side wall 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.

[0050] The wave soldering nozzle assembly 36 further includes a throttle gate 72, which is hingedly secured to the end walls 40, 42 of the nozzle core holder. As shown, the throttle gate 72 is secured to the nozzle core holder on the loading side of the wave soldering nozzle assembly 36 and is configured to selectively block a portion of the solder dispensing baffle 70 to reduce the amount of solder entering the solder dispensing baffle. As shown, the throttle gate 72 is located on the loading side of the nozzle assembly, but it will be understood that the throttle gate can be located elsewhere, such as in the middle or on the unloading side. The throttle gate 72 is coupled to a motion mechanism, generally designated 74, which in turn is coupled to an actuator 76 to move the throttle gate 72 between an open position and a closed position. The actuator 76 is sometimes referred to herein as a second actuator or a throttle gate actuator.

[0051] Specifically, the throttle gate 72 includes one or more plates disposed along the length of the solder dispensing baffle 70. In one embodiment, the individual plates are sized to block or otherwise prevent solder flow along the length of the solder dispensing baffle through an opening in the solder dispensing baffle. The throttle gate 72 is hingedly secured to the end walls 40, 42 of the nozzle core holder by hinge pins 78. Figure 5As best shown, one end of a hinge pin 78 extends through an opening in the corresponding end wall 42 of the nozzle cartridge. The hinge pin 78 is securely fastened to an arm 80 having an outwardly extending pin 82. This arrangement allows the arm 80 to rotate about the axis of the hinge pin 78 as the throttle gate 72 rotates. The other end of the hinge pin may or may not include a similar arm.

[0052] The motion mechanism 74 is a generally U-shaped structure having a front wall 84 facing the second longitudinal side wall 46 of the nozzle core frame and two side walls 86, 88 facing the corresponding end walls 40, 42 of the nozzle core frame, respectively. The motion mechanism 74 is designed to move laterally (horizontally) relative to the nozzle core frame. The front wall 84 includes an opening that is configured to receive the connecting rod 62 coupled to the outlet flap actuator 54. The motion mechanism 24 is coupled to the throttle gate actuator 76, which is configured to provide lateral movement of the motion mechanism. The motion mechanism 74, and therefore the movement of the throttle gate 72 between the open and closed positions, can be controlled in real time by controlling the longitudinal displacement of the actuator arm 90 of the actuator 76. Like the outlet flap actuator 54, the actuator is secured to the solder pot 30 via the actuator support frame 58. The throttle gate actuator 76 is located alongside 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 mechanism via an actuator segment 92.

[0053] Like the outlet flap actuator 54, the throttle gate actuator 76 is a linear actuator, so the actuator arm 90 moves in the longitudinal direction. The actuator segment 92 connects the actuator arm 90 to the connecting rod 94 of the linkage mechanism to transmit motion from the actuator arm to the connecting rod. The other end of the connecting rod 94 is fixed to the front wall 84 of the motion mechanism 74. Therefore, the longitudinal movement of the actuator arm 90 causes the actuator segment 92 and the connecting rod 94 to move in the same longitudinal direction as the actuator arm. In some embodiments, the actuator 76 and the connecting rod 94 are oriented so that the actuator arm 90 moves the connecting rod in the horizontal direction. In certain embodiments, the actuator 76 includes an electromechanical actuator that provides motion for position adjustment of the throttle gate 72. The actuator 76 is driven by computer-controlled machine software (supported by the controller 26) and includes an encoder that can transmit position indications to the machine software. The actuator 76 can be controlled in real time via the controller 26 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. In turn, the actuator 76 is configured to receive commands from the controller 26 during operation of the wave soldering machine 10 to cause the actuator 76 to adjust the position of the throttle gate 72.

[0054] The side wall 88 of the movement mechanism 74 is connected to the arm 80 of the throttle gate 72. Figure 5 As best shown in FIG. 8 , the outwardly extending pin 82 extends through a slot 96 formed in the side wall 88. As previously described, the other side wall 86 may or may not be similarly configured. This arrangement enables lateral (horizontal) movement of the motion mechanism 74 to move the throttle gate 72 between its open and closed positions. Each side wall 86, 88 further includes two slots formed therein, each receiving a pin to guide movement of the motion mechanism 74 relative to the wave soldering nozzle assembly 36. A connecting rod 94 is secured to the front wall 84 of the motion mechanism 74. Thus, when the connecting rod 94 is extended by the throttle gate actuator 76, the front wall 84 of the motion mechanism 74 is positioned against the second longitudinal side wall 46 of the nozzle core. In this position, the throttle gate 72 is in the open position. When the connecting rod 94 is retracted by the throttle gate actuator 76, the front wall 84 of the motion mechanism 74 is spaced apart from the second longitudinal side wall 46 of the nozzle core. In this position, the throttle gate 72 is in the closed position.

[0055] The longitudinal displacement of the actuator arm 90 enables 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 rod 94. Therefore, the actuator arm 90 is configured to move the connecting rod 94 in a horizontal direction along the axis of the actuator arm. Since the front wall 84 of the kinematic mechanism 74 is coupled to the connecting rod 94, the extension or retraction of the actuator arm 90 causes the kinematic mechanism to translate.

[0056] refer to Figure 10 and Figure 11 , the actuator arm 90 associated with the throttle actuator 76 is Figure 10 is shown in the retracted position and in Figure 11 is shown in the extended position. Figure 12 and Figure 13 , Figure 11 and Figure 12 The throttle gate 72 is shown in an open position. Figure 10 and Figure 13 The throttle gate 72 is shown 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 dispensing baffle 70, thereby optimizing the solder contact time. The controller 26 is configured to achieve optimal soldering characteristics for the wave nozzle assembly 36. As previously described, control of the throttle gate 72, along with controlling the operation of the outlet vane 50, helps achieve optimal soldering characteristics.

[0057] As previously described, the first actuator 54 is configured to control the outlet flap 50 to control the flow of solder over the outlet flap's rear gate 68, thereby optimizing 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 dispensing baffle 70, thereby optimizing solder contact time. This feature reduces copper dissolution during the wave soldering process.

[0058] refer to Figure 14 , second actuator 76 extends, rotating throttle gate 72 to the open position. Opening throttle gate 72 increases the solder flow rate through solder dispensing baffle 70, as indicated by arrow A, thereby extending the contact time of the printed circuit board traveling along the solder wave. Furthermore, first actuator 54 retracts, pivoting outlet flap 50 to the raised position. Due to the increased solder flow rate caused by opening throttle gate 72, outlet flap 50 rises.

[0059] refer to Figure 15 , second actuator 76 retracts, rotating throttle gate 72 to the closed position. Closing throttle gate 72 reduces the solder flow through solder dispensing baffle 70, as indicated by arrow B, thereby reducing the contact time of the printed circuit board traveling along the solder wave. Furthermore, first actuator 54 extends, pivoting outlet flap 50 to the lowered position. Due to the reduced solder flow caused by closing throttle gate 72, outlet flap 50 is lowered.

[0060] refer to Figure 16 , which shows Figure 14 , the throttle gate 72 in the open position and the outlet wing 50 in the raised position are shown, showing the printed circuit board traveling along the direction C on the solder wave. As previously described, the printed circuit board 12 travels a maximum contact length D on the solder wave. The throttle gate 72 and the outlet wing 50 are controlled (by the controller 26) to match the speed of the printed circuit board (Vpcb) with the speed of the solder flow (Vs). As previously described, when these two speeds (Vpcb and Vs) are equal, the possibility of soldering defects, particularly solder bridging, is significantly reduced. When the speed is not optimized, the resulting defects may require rework or scrapping.

[0061] refer to Figure 17 , which shows Figure 15 , with the throttle gate 72 shown in the closed position and the outlet flap 50 in the lowered position, the printed circuit board 12 is shown traveling on the solder wave in the direction E. As described above, the printed circuit board 12 travels on the solder wave a minimum contact length F. The throttle gate 72 and the outlet flap 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).

[0062] In some embodiments, the wave soldering nozzle assembly 36 further includes a scum damper that is fixed to the nozzle frame and is configured to reduce turbulence as the solder flows back toward the reservoir 32, thereby reducing solder balls that may form in the reservoir. One or more nitrogen gas lines may be provided to create an inert atmosphere during the wave soldering process.

[0063] In some embodiments, the shield extends around the wave soldering nozzle assembly 36. In some embodiments, the shield surrounds the wave soldering nozzle assembly to form a substantially airtight inert atmosphere around the solder wave. In some embodiments, the shield is substantially impermeable to nitrogen. The shield includes two sealed openings through which the connecting rods extend. Each sealed opening has an inner surface that is substantially sealed in engagement with the outer surface of a corresponding connecting rod. Since each connecting rod has a substantially constant cross-section over a portion through which the connecting rod passes the sealed opening, the connecting rod is able to substantially form an airtight seal with the inner surface of the corresponding sealed opening. In some embodiments, the inner surface of each sealed opening is annular, and the outer surface of each connecting rod has a matching circular profile so that the inner surface is substantially sealed in engagement with the outer surface when each connecting rod moves through the sealed opening along the axial direction of the connecting rod.

[0064] The present disclosure also provides a method for adjusting the flow rate of a solder wave of a wave soldering nozzle assembly of a wave soldering machine. In some embodiments, the method can be performed using a wave soldering station 24 or a wave soldering machine 10 including the wave soldering station 24.

[0065] In some embodiments, the method includes delivering solder to a wave soldering nozzle assembly 36 comprising a nozzle core frame and an outlet wing hingedly attached to the nozzle core frame; adjusting a flow rate of the solder wave by causing a linear actuator connected to the outlet wing to adjust an orientation of the outlet wing relative to the nozzle core frame; and performing a wave soldering operation on a printed circuit board.

[0066] In some embodiments, flow rate regulation of the solder wave is achieved by rotating the outlet vane relative to the nozzle core through a linkage mechanism coupled to the linear actuator and the outlet vane. In some embodiments, the linkage mechanism includes a connecting rod and a rotating link, and the method includes translating the connecting rod along an operating axis of the linear actuator to rotate the rotating link.

[0067] In some embodiments, the method includes forming a substantially airtight atmosphere over the solder wave. In some embodiments, this is achieved by a shield surrounding the wave soldering station 24. The shield includes at least one sealed opening through which a corresponding connecting rod of the linkage extends. In some embodiments, the shield includes two sealed openings. A first connecting rod extends through the first sealed opening, and a second connecting rod extends through the second sealed opening. An inner surface of each sealed opening is in substantially sealing engagement with an outer surface of the corresponding connecting rod.

[0068] In some embodiments of the method, the actuator is coupled to a controller 26 that is used to control the movement of the linear actuator.

[0069] As used herein, "solder wave height" describes the vertical dimension of the solder wave.

[0070] A variety of different controllers can perform the various operations discussed above. For example, as discussed above, a controller (such as controller 26) can control components of the wave soldering machine 10 (including the wave soldering station 24) and perform other operations. Using data stored in associated memory and / or storage devices, the controller can execute one or more instructions stored on one or more non-transitory computer-readable media, which the controller can include and / or be connected to, which can generate manipulation data. In some examples, the controller can include one or more processors or other types of controllers. In one example, the controller is at least one processor or includes at least one processor. In another example, in addition to or instead of a general-purpose processor, the controller uses an application-specific integrated circuit to perform at least a portion of the operations discussed above, which is customized to perform specific operations. As illustrated by these examples, many specific combinations of hardware and software can be used to perform the operations described herein according to examples of the present disclosure, and the present disclosure is not limited to any specific combination of hardware and software components. Examples of the present disclosure can include a computer program product that is configured to perform the methods, processes, and / or operations discussed above. The computer program product may be or include one or more controllers and / or processors configured to execute instructions to perform the methods, processes, and / or operations discussed above.

[0071] For each embodiment, the solder flow through the nozzle can be controlled to reduce or even prevent dross from recirculating through the nozzle. By reducing the width of the solder wave, dross is reduced. Each embodiment can reduce the width of the solder wave.

[0072] In some embodiments, the wave soldering nozzle assembly further includes a scum box secured to the nozzle housing and configured to reduce turbulence as the solder reflows toward the reservoir, thereby further reducing solder balls that may form within the reservoir.

[0073] In some embodiments, one or more nitrogen gas lines may be provided to create an inert atmosphere during the wave soldering process.

[0074] In some embodiments, the minimum contact and maximum contact may vary.

[0075] As used herein, "solder wave width" describes the cross-sectional dimensions of the actual solder wave, and "contact length" describes the distance on the PCB that the solder wave is in contact with at any given point in time. As used herein, the term "length" refers to the contact length parallel to the direction of travel of the PCB. As used herein, the term "height" refers to the height of the solder wave above the solder dispensing barrier.

[0076] Having thus described several aspects of at least one embodiment of the present disclosure, it will be appreciated that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be a part of this disclosure and are intended to fall within the spirit and scope of this disclosure. Therefore, the foregoing description and accompanying drawings are intended only as examples.

Claims

1. A wave soldering machine for performing a wave soldering operation on a printed circuit board, the wave soldering machine comprising: case; a conveyor coupled to the housing, the conveyor configured to transport a printed circuit board through the housing; A wave soldering station is coupled to the housing, the wave soldering station comprising: a solder pot having a solder reservoir, a flow conduit arranged in the reservoir of the solder pot, a wave soldering nozzle assembly coupled to the flow conduit, the wave soldering nozzle assembly having: a solder dispensing baffle configured to generate a solder wave; a throttle gate coupled to the flow conduit and configured to move from an open position that allows solder flow to completely pass through the solder dispensing baffle and a closed position that inhibits a portion of the solder flow from passing through the solder dispensing baffle; and an outlet flap coupled to the flow conduit and configured to move from a lowered position that increases solder flow and from a raised position that reduces solder flow; and A controller is coupled to the wave soldering station to control movement of the throttle gate and the outlet flap to control the solder flow.

2. The wave soldering machine according to claim 1, wherein: The wave solder nozzle assembly further includes a core frame supported by the flow conduit and configured to support the solder distribution baffle.

3. The wave soldering machine according to claim 2, wherein: The outlet vane is rotatable relative to the nozzle core frame about a hinge to move the outlet vane between the lowered position and the raised position.

4. The wave soldering machine according to claim 3, wherein: The wave solder nozzle assembly further includes an outlet flap actuator connected to the outlet flap and coupled to the controller, the outlet flap actuator being configured to adjust a position of the outlet flap between the lowered position and the raised position.

5. The wave soldering machine according to claim 4, wherein: The outlet flap actuator is connected to the outlet flap via a linkage mechanism comprising at least one rotating link having a first end rotatably coupled to one end of the outlet flap and a second end rotatably coupled to an actuator arm of the outlet flap actuator.

6. The wave soldering machine according to claim 5, wherein: The linkage mechanism further includes a cross bar extending perpendicularly to the at least one rotating link and rotatably coupled to the at least one rotating link; and at least one connecting rod coupling the cross bar to the actuator arm and extending perpendicularly to the cross bar, the at least one connecting rod being connected to the actuator arm via an actuator segment.

7. The wave soldering machine according to claim 4, wherein: The throttle gate includes a plate and a hinge pin hingedly secured to the nozzle core.

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

9. The wave soldering machine according to claim 8, wherein: The wave soldering nozzle assembly further includes a linkage mechanism secured to a motion mechanism coupled to the throttle plate.

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

11. A wave soldering station of a wave soldering machine configured to perform a wave soldering operation on a printed circuit board, the wave soldering station comprising: a solder pot having a solder reservoir; a flow conduit disposed in the reservoir of the solder pot; as well as a wave soldering nozzle assembly coupled to the flow conduit, the wave soldering nozzle assembly having: a solder dispensing baffle configured to generate a solder wave; a throttle gate coupled to the flow conduit and configured to move from an open position and a closed position, the open position permitting solder flow to completely pass through the solder dispensing baffle and the closed position inhibiting a portion of the solder flow from passing through the solder dispensing baffle; and an outlet vane coupled to the flow conduit and configured to move from a lowered position to increase solder flow and from a raised position to decrease solder flow, Wherein, a controller coupled to the wave soldering station is configured to control movement of the throttle gate and the outlet flap to control the solder flow.

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

13. The wave soldering station of claim 12, wherein: The outlet vane is rotatable relative to the nozzle core frame about a hinge to move the outlet vane between the lowered position and the raised position.

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

15. The wave soldering station of claim 14, wherein: The outlet flap actuator is connected to the outlet flap via a linkage mechanism comprising at least one rotating link having a first end rotatably coupled to one end of the outlet flap and a second end rotatably coupled to an actuator arm of the outlet flap actuator.

16. The wave soldering station of claim 15, wherein: The linkage mechanism further includes a cross bar extending perpendicularly to the at least one rotating link and rotatably coupled to the at least one rotating link; and at least one connecting rod coupling the cross bar to the actuator arm and extending perpendicularly to the cross bar, the at least one connecting rod being connected to the actuator arm via an actuator segment.

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

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

19. The wave soldering station of claim 18, wherein: The wave soldering nozzle assembly further includes a linkage mechanism secured to a motion mechanism coupled to the throttle plate.

20. The wave soldering station of claim 19, wherein: The kinematic mechanism is coupled to an arm that is fixed to the hinge pin of the throttle gate.

21. A method for adjusting the flow rate of a solder wave of a wave soldering nozzle assembly of a wave soldering machine, the method comprising: delivering solder to a wave soldering nozzle assembly comprising: a solder dispensing baffle configured to generate a solder wave; a throttle gate coupled to a flow conduit and configured to move from an open position that allows solder flow to completely pass through the solder dispensing baffle and a closed position that inhibits a portion of the solder flow from passing through the solder dispensing baffle; and an outlet flap coupled to the flow conduit and configured to move from a lowered position that increases solder flow and from a raised position that reduces solder flow; adjusting the flow rate of the solder wave by adjusting the position of the throttle gate by a throttle gate actuator connected to the throttle gate and adjusting the position of the outlet vane relative to the nozzle core holder by an outlet vane actuator coupled to the outlet vane; and Performing wave soldering operations on printed circuit boards.

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