System and method for controlling solder flow in crest welder

Abstract

A wave soldering machine is configured to perform a wave soldering operation on a printed circuit board. The crest welder includes a housing and a transfer device coupled to the housing. The conveying device is configured to convey the printed circuit board through the housing. The crest welder further includes a crest soldering station coupled to the housing. The wave soldering station includes a solder tank having a solder reservoir, a flow conduit positioned 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 dispensing baffle configured to generate solder waves. The wave soldering nozzle assembly is configured to control a width of a solder wave passing through the solder dispensing baffle to produce a maximum width solder wave and a minimum width solder wave.

Description

Background of the Invention 1. Technical Field

[0002] 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 solder flow. 2. Background technology

[0003] In the manufacture of printed circuit boards, electronic components can be mounted to the printed circuit board by 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 is caused (by a pump) to flow upward through a wave soldering nozzle and contact the portion of the printed circuit board to be soldered.

[0004] A typical wave soldering 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 the operator responsible for making such adjustments to a solder pot filled with molten solder. It is also desirable to minimize the dross generated by the solder flow over the nozzle. Summary of the invention

[0005] 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 convey 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 pot having a solder reservoir, a flow conduit positioned in 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 dispensing baffle configured to generate a solder wave. The wave soldering nozzle assembly is configured to control the width of the solder wave through the solder dispensing baffle to generate a maximum width solder wave and a minimum width solder wave.

[0006] Embodiments of the wave soldering machine may further include configuring the wave soldering nozzle assembly to include an inner frame supported by the flow conduit and configured to support a solder distribution baffle. The wave soldering nozzle assembly may further include at least two nozzle plates. Each nozzle plate may be configured to move between an open position and a closed position relative to the solder distribution baffle, in which the solder flows through the solder distribution baffle and the nozzle plate, and in which the solder is inhibited from flowing through the solder distribution baffle and the nozzle plate. The wave soldering nozzle assembly may further include an actuator for each nozzle plate, the actuator being configured to move the nozzle plate between an open position and a closed position. The wave soldering nozzle assembly may further include a connecting rod for each nozzle plate, the connecting rod being configured to fix the actuator to the nozzle plate. The actuator may be fixed to the solder pot by an actuator support. The actuator may be connected to a controller to control the movement of the actuator. The wave soldering nozzle assembly may further include four nozzle plates arranged along the width of the solder distribution baffle. The solder distribution shield and each nozzle plate may each include a pattern of openings to enable solder to pass through the solder distribution shield and the nozzle plates.

[0007] The wave soldering nozzle assembly may further include at least two nozzle plates. Each nozzle plate may be configured to rotate between an open position and a closed position relative to the solder distribution baffle, in which the solder flows through the solder distribution baffle and the nozzle plate, and in which the solder is inhibited from flowing through the solder distribution baffle and the nozzle plate. The wave soldering nozzle assembly may further include an actuator for each nozzle plate, the actuator being configured to rotate the nozzle plate between the open position and the closed position. The wave soldering nozzle assembly may further include a connecting rod for each nozzle plate, the connecting rod being configured to fix the actuator to the nozzle plate and being configured to rotate the nozzle plate between the open position and the closed position. The actuator may be connected to a controller to control the movement of the actuator. The wave soldering nozzle assembly may further include three nozzle plates arranged along the width of the solder distribution baffle. The solder distribution baffle includes an opening pattern to enable solder to pass through the solder distribution baffle.

[0008] The wave soldering station may further include at least two pump impellers positioned adjacent to the flow conduit in the reservoir of the solder pot. The flow conduit may include at least two chambers. Each pump impeller may be in fluid communication with the corresponding chamber. The solder flow in each of the at least two chambers may be controlled by the corresponding pump impeller in the at least two pump impellers. Each pump impeller in the at least two pump impellers may include a centrifugal pump to pump molten solder to the wave soldering nozzle assembly. The at least two pump impellers may include three pump impellers. The at least two chambers may include three chambers. Each chamber in the at least two chambers may include an inlet connected to the corresponding pump impeller. Each pump impeller in the at least two pump impellers may be coupled to a controller to control the solder flow provided by the pump impeller.

[0009] Another aspect of the present disclosure relates to a wave soldering station of a wave soldering machine. The wave soldering station is configured to perform a wave soldering operation on a printed circuit board. In one embodiment, the wave soldering station includes a solder pot having a solder reservoir, a flow conduit positioned in 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 dispensing baffle configured to generate a solder wave. The wave soldering nozzle assembly is configured to control the width of the solder wave passing through the solder dispensing baffle to generate a maximum width solder wave and a minimum width solder wave.

[0010] Embodiments of the wave soldering station may further include further configuring the wave soldering nozzle assembly to include an inner frame supported by the flow conduit and configured to support the solder dispensing baffle. The wave soldering nozzle assembly may further include at least two nozzle plates. Each nozzle plate may be configured to move between an open position and a closed position relative to the solder dispensing baffle, in which the solder flows through the solder dispensing baffle and the nozzle plate, and in which the solder is inhibited from flowing through the solder dispensing baffle and the nozzle plate. The wave soldering nozzle assembly may further include an actuator for each nozzle plate, the actuator being configured to move the nozzle plate between the open position and the closed position. The wave soldering nozzle assembly may further include a connecting rod for each nozzle plate, the connecting rod being configured to fix the actuator to the nozzle plate. The actuator may be fixed to the solder pot by an actuator support. The actuator may be connected to a controller to control the movement of the actuator. The wave soldering nozzle assembly may further include four nozzle plates arranged along the width of the solder dispensing baffle. The solder distribution shield and each nozzle plate may each include a pattern of openings to enable solder to pass through the solder distribution shield and the nozzle plates.

[0011] The wave soldering nozzle assembly may further include at least two nozzle plates. Each nozzle plate may be configured to rotate between an open position and a closed position relative to the solder distribution baffle, in which the solder flows through the solder distribution baffle and the nozzle plate, and in which the solder is inhibited from flowing through the solder distribution baffle and the nozzle plate. The wave soldering nozzle assembly may further include an actuator for each nozzle plate, the actuator being configured to rotate the nozzle plate between the open position and the closed position. The wave soldering nozzle assembly may further include a connecting rod for each nozzle plate, the connecting rod being configured to fix the actuator to the nozzle plate and being configured to rotate the nozzle plate between the open position and the closed position. The actuator may be connected to a controller to control the movement of the actuator. The wave soldering nozzle assembly further includes three nozzle plates arranged along the width of the solder distribution baffle. The solder distribution baffle may include an opening pattern to enable solder to pass through the solder distribution baffle.

[0012] The wave soldering station may further include at least two pump impellers positioned adjacent to the flow conduit in the reservoir of the solder pot. The flow conduit may include at least two chambers. Each pump impeller may be in fluid communication with the corresponding chamber. The solder flow in each of the at least two chambers may be controlled by the corresponding pump impeller in the at least two pump impellers. Each pump impeller in the at least two pump impellers may include a centrifugal pump to pump molten solder to the wave soldering nozzle assembly. The at least two pump impellers may include three pump impellers. The at least two chambers may include three chambers. Each chamber in the at least two chambers may include an inlet connected to the corresponding pump impeller. Each pump impeller in the at least two pump impellers may be coupled to a controller to control the solder flow provided by the pump impeller.

[0013] Another aspect of the present disclosure relates to a method for adjusting the width 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 including a solder dispensing shield; adjusting the width of the solder wave with the wave soldering nozzle assembly by selectively delivering solder to multiple portions of the solder dispensing shield; and performing a wave soldering operation on a printed circuit board.

[0014] Embodiments of the method may further include adjusting the width of the solder wave by moving one of the at least two nozzle plates. Each nozzle plate may be configured to move between an open position and a closed position relative to the solder dispensing baffle, in which the solder flows through the solder dispensing baffle and the nozzle plate, and in which the solder is inhibited from flowing through the solder dispensing baffle and the nozzle plate. The wave soldering nozzle assembly may further include an actuator for each nozzle plate, the actuator being configured to move the nozzle plate between the open position and the closed position. The method may further include controlling the actuator with a controller.

[0015] Adjusting the width of the solder wave can be achieved by rotating one of the at least two nozzle plates. Each nozzle plate can be configured to rotate relative to the solder distribution baffle between an open position and a closed position, in which the solder flows through the solder distribution baffle and the nozzle plate, and in which the solder is inhibited from flowing through the solder distribution baffle and the nozzle plate. The wave soldering nozzle assembly can further include an actuator for each nozzle plate, the actuator being configured to rotate the nozzle plate between the open position and the closed position. The method can further include controlling the actuator with a controller.

[0016] Adjusting the width of the solder wave can be achieved by selectively controlling at least two pump impellers positioned in a reservoir of a solder tank of a wave soldering station. The wave soldering station may include a flow conduit having at least two chambers. Each pump impeller may be in fluid communication with a corresponding chamber. The solder flow in each of the at least two chambers may be controlled by a corresponding pump impeller in the at least two pump impellers. Each of the at least two pump impellers may include a centrifugal pump to pump molten solder to a wave soldering nozzle assembly. The at least two pump impellers may include three pump impellers. The at least two chambers may include three chambers. Each of the at least two chambers may include an inlet connected to a corresponding pump impeller. The method may further include controlling each of the at least two pump impellers with a controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The 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 the same reference numeral. For the purpose of clarity, not every component may be labeled in every figure. In the drawings:

[0018] Figure 1 It is a three-dimensional picture of a wave soldering machine;

[0019] Figure 2 is a side view of a wave soldering machine with the outer shell removed to expose the internal components of the wave soldering machine;

[0020] Figure 3 is a cross-sectional view of a wave soldering station of an embodiment of the present disclosure;

[0021] Figure 4 is a perspective view of a wave soldering station showing a printed circuit board disposed adjacent to the wave soldering station;

[0022] Figure 5 It is an exploded perspective view of a wave soldering station;

[0023] Figure 6 is a perspective view of a wave soldering nozzle assembly of a wave soldering station;

[0024] Figure 7 It is an exploded perspective view of the wave soldering nozzle assembly;

[0025] Figure 8 is a top view of a wave soldering nozzle assembly showing a printed circuit board disposed adjacent to the wave soldering nozzle assembly;

[0026] Fig. 9 is a cross-sectional view of a portion of a wave soldering nozzle assembly showing a plate of the wave soldering nozzle assembly in a closed position;

[0027] Fig.10is a cross-sectional view of a portion of a wave soldering nozzle assembly showing a plate of the wave soldering nozzle assembly in a partially open position;

[0028] Fig.11 is a cross-sectional view of a portion of a wave soldering nozzle assembly showing a plate of the wave soldering nozzle assembly in an open position;

[0029] Fig.12 is a cross-sectional view of a wave soldering station of another embodiment of the present disclosure;

[0030] Fig.13 It is a three-dimensional picture of the wave soldering station;

[0031] Fig.14 It is an exploded perspective view of a wave soldering station;

[0032] Fig.15 is an exploded perspective view of a wave soldering nozzle assembly of a wave soldering station;

[0033] Fig.16 is a cross-sectional view of a portion of a wave soldering nozzle assembly showing a plate of the wave soldering nozzle assembly in an open position;

[0034] Fig.17 is a cross-sectional view of a portion of a wave soldering nozzle assembly showing a plate of the wave soldering nozzle assembly in a closed position;

[0035] Fig.18 is a cross-sectional view of a wave soldering station of another embodiment of the present disclosure;

[0036] Fig.19 It is a three-dimensional picture of the wave soldering station;

[0037] Fig. 20 It is an exploded perspective view of a wave soldering station;

[0038] Fig.21 is a top view of a portion of a wave soldering nozzle assembly of a wave soldering station; and

[0039] Fig. 22 A perspective view of a portion of a wave soldering nozzle assembly of a wave soldering station. DETAILED DESCRIPTION

[0040] The present disclosure is not limited in its application to the construction details and component arrangements set forth in the following description or shown in the accompanying drawings. The present disclosure can have other embodiments and can be practiced or implemented in various ways. Likewise, the wording and terminology used herein are for the purpose of description 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.

[0041] Embodiments of the present disclosure relate to controlling the flow of molten solder over a nozzle in order to vary the width of a solder wave. One object is to provide the ability to adjust (reduce) the width of a solder wave in order to reduce dross produced by the solder wave. Another object is to automate this adjustment and allow computer control to eliminate the need for human intervention when adjustments are needed based on the product being processed.

[0042] For illustrative purposes, and with reference to Figure 1 , embodiments of the present disclosure will now be described with reference to a wave soldering machine, generally designated 10, for performing solder coating on a printed circuit board 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 suitable for housing 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., six degrees relative to the horizontal) through a channel 18 to condition the printed circuit board for wave soldering, including a fluxing station generally designated 20 and a preheating station generally designated 22 on the channel. Once conditioned (i.e., heated), the printed circuit board 12 travels to a wave soldering station generally designated 24 to apply solder to the printed circuit board. The controller 26 is configured to automate the operation of the various 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.

[0043] 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 a plurality of preheaters (e.g., preheaters 22a, 22b, and 22c) 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 disposed 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 arrives at another station (e.g., a pick-and-place machine) disposed in the production line.

[0044] 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 2As shown, the flux management system 28 is positioned 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.

[0045] Embodiments of the present disclosure relate to minimizing dross associated with molten solder. Different combinations of tin, lead, and other metals are used to produce leaded solder and lead-free solder. Dross is a mass of solid impurities floating on the surface of or dispersed within the molten solder. For solder, dross tends to form on the surface of tin-based molten metals, and oxidized impurities in the metal produce dross.

[0046] Sliding solder nozzle plate design

[0047] 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 contain molten solder. In one embodiment, the solder pot 30 is a box-shaped structure that supports the various components of the wave soldering station 24, including a flow conduit 34 within the reservoir 32, the flow conduit having one or two chambers. The flow conduit 34 is designed to deliver pressurized molten solder to an opening or nozzle of a wave soldering nozzle assembly, generally indicated at 36. As will be described in more detail below, the wave soldering nozzle assembly 36 is configured to direct the molten solder to the bottom of the printed circuit board 12 via a channel 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.

[0048] The wave soldering station 24 further includes a pump impeller 38 positioned within the reservoir 32 of the solder pot 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 a 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 downtime during processing.

[0049] Additional references Figure 5 and Figure 6, the wave soldering nozzle assembly 36 is coupled to four actuators (actuators 40a, 40b, 40c, 40d) to variably adjust the width of the solder wave during the wave soldering operation to increase or decrease the contact length of the solder wave. The actuators 40a, 40b, 40c, 40d are fixed to the solder pot 30 by an actuator support frame 42, which is fixed to the side wall of the solder pot by suitable fasteners (e.g., bolts). Alternatively, the actuator support frame 42 can be fixed to the solder pot 30 by another method (e.g., welding). As shown, the actuators 40a, 40b, 40c, 40d are fixed to the actuator support frame 42, which is configured to firmly support the actuator relative to the solder pot 30. Actuators 40a, 40b, 40c, 40d are positioned beside and form part of the wave soldering nozzle assembly 36 to adjust the nozzle of the wave soldering nozzle assembly through corresponding connecting rods 44a, 44b, 44c, 44d, which are connected to their corresponding actuators to provide movement to variably adjust the nozzle opening width of the wave soldering nozzle assembly. In some embodiments, each actuator 40a, 40b, 40c, 40d includes an electromechanical actuator that implements the movement for adjusting the nozzle opening width. The actuators 40a, 40b, 40c, 40d are driven by computer-controlled machine software (supported by the controller 26) and include encoders that can communicate position indications to the machine software.

[0050] refer to Figure 7 and Figure 8 , the wave soldering nozzle assembly 36 includes a nozzle inner frame 48 having two end walls 50, 52, a first longitudinal support element 54 and a second longitudinal support element 56 extending between the end walls. As shown, the nozzle inner frame 48 may further include a plurality of transverse support elements, each indicated at 58, extending between the first longitudinal support element 54 and the second longitudinal support element 56. The nozzle inner frame 48 also directs the solder flow through a nozzle throat defined between the first longitudinal support element 54 and the second longitudinal support element 56. The wave soldering nozzle assembly 36 further includes an elongated solder distribution baffle 60 secured to the first longitudinal support element 54 of the nozzle inner frame 48. The solder distribution baffle 60 is secured to the first longitudinal support element 54, for example, by screws through five openings located on the loading side of the baffle. In one embodiment, one side (i.e., loading side 64) of solder distribution baffle 60 is secured to or integrally formed with first longitudinal support member 54, and the other side (i.e., unloading side 66) of solder distribution baffle is secured to or integrally formed with second longitudinal support member 56. In one embodiment, solder distribution baffle 60 includes a unique pattern of elongated openings to allow molten solder to flow through the baffle.

[0051] The wave soldering nozzle assembly 36 further includes four solder nozzle plates 62a, 62b, 62c, 62d, which are fixed to corresponding connecting rods 44a, 44b, 44c, 44d and moved by corresponding actuators 40a, 40b, 40c, 40d. Each solder nozzle plate 62a, 62b, 62c, 62d includes an elongated opening of the same unique pattern. The unique hole pattern design incorporated into the solder distribution baffle and the solder nozzle plate produces uniform, parallel waves over the entire solder contact area while maintaining a six-degree liquid molten solder plane parallel to the six-degree plane of the conveyor 16 that conveys the circuit board 12. As shown, each solder nozzle plate 62a, 62b, 62c, 62d is moved by its corresponding actuator 40a, 40b, 40c, 40d to control the flow of molten solder through the solder distribution baffle 60 and the solder distribution baffle.

[0052] In some embodiments, the wave soldering nozzle assembly 36 further includes a scum box that is fixed to the nozzle frame and is configured to reduce turbulence as the solder travels back to the reservoir 32, thereby reducing solder beads that may form in the reservoir. One or more nitrogen gas pipes may be provided to create an inert atmosphere during the wave soldering process.

[0053] Fig. 9 The solder nozzle plate (eg, solder nozzle plate 62a) is shown in a fully extended position so that the solder nozzle plate almost completely overlaps the solder dispensing shield 60 to inhibit molten solder from flowing through the nozzle. As shown, molten solder is prevented from flowing through the solder dispensing shield 60.

[0054] Fig.10 The solder nozzle plate (e.g., solder nozzle plate 62c) is shown in a first partially extended position so that the solder nozzle plate partially overlaps the solder dispensing baffle 60 to partially allow molten solder to flow through the nozzle. As shown, the molten solder flow can partially pass through the solder dispensing baffle 60 and the solder nozzle plate 62c. The printed circuit board 12 passing through the solder wave 64 has minimal contact with the solder wave 64.

[0055] Fig.11 The solder nozzle plate (e.g., solder nozzle plate 62b and / or solder nozzle plate 62d as shown) is shown in a second partially extended position so that the solder nozzle plate barely overlaps the solder dispensing baffle to allow molten solder to flow completely through the nozzle. As shown, the molten solder flow is able to completely pass through the solder dispensing baffle 60 and the solder nozzle plate 62d. The printed circuit board 12 passing through the solder wave 66 has the most contact with the solder wave 66.

[0056] The result is that the solder wave can be controlled by opening and closing the solder nozzle plates 62a, 62b, 62c, 62d. For example, the solder wave can be controlled so that the solder wave extends through the solder dispensing barrier 60 in the middle of the solder dispensing barrier by closing the solder nozzle plates 62a, 62d and opening the solder nozzle plates 62b, 62c. With this arrangement, dross is also reduced because the width of the solder wave is significantly reduced.

[0057] Restrictor design

[0058] refer to Fig.12 and Fig.13 In another embodiment, the wave soldering station 24 includes a solder pot 70 defining a reservoir 72 configured to contain molten solder. In one embodiment, the solder pot 70 is a box-shaped structure that supports components of the wave soldering station 24, including a flow conduit 74 having one or more chambers within the reservoir 72. The flow conduit 74 is designed to deliver pressurized molten solder to an opening or nozzle of a wave soldering nozzle assembly, generally indicated at 76. The wave soldering nozzle assembly 76 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 72. Specifically, the wave soldering nozzle assembly 76 is capable of adjusting the height and width of the solder wave when performing a wave soldering operation.

[0059] The wave soldering station 24 further includes a pump impeller 78 positioned within the reservoir 72 of the solder pot 70 adjacent to an inlet disposed in the flow conduit 74. The pump impeller 78 pressurizes the molten solder in the reservoir 72 to vertically pump the molten solder within the reservoir to a wave soldering nozzle assembly 76. In one embodiment, the pump impeller 78 is a centrifugal pump that is appropriately sized to pump the molten solder to the nozzle of the wave soldering nozzle assembly 76. The wave soldering nozzle assembly 76 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 downtime during the process.

[0060] Additional references Fig.14 and Fig.15, the wave soldering nozzle assembly 76 is coupled to three actuators (actuators 80a, 80b, 80c) to cut off the flow of molten solder to the various parts of the wave soldering nozzle assembly. The actuators 80a, 80b, 80c are fixed to the solder pot 70 by an actuator support frame 82, which is fixed to the side wall of the solder pot 70 by suitable fasteners (e.g., bolts). Alternatively, the actuator support frame 82 can be fixed to the solder pot 70 by another method (e.g., welding). As shown, the actuators 80a, 80b, 80c are fixed to the actuator support frame 82, which is configured to firmly support the actuator relative to the solder pot 70. Actuators 80a, 80b, 80c are positioned beside and form part of the wave soldering nozzle assembly 76 to adjust the nozzle of the wave soldering nozzle assembly through corresponding connecting rods 84a, 84b, 84c, which are connected to their corresponding actuators. In some embodiments, each actuator 80a, 80b, 80c includes an electromechanical actuator that provides movement for adjusting the width of the nozzle opening. The actuators 80a, 80b, 80c are driven by computer-controlled machine software (supported by the controller 26) and incorporate encoders that can pass position indications to the machine software.

[0061] The wave soldering nozzle assembly 76 includes a nozzle inner frame 88 having two end walls 90, 92, a first longitudinal support element 94 and a second longitudinal support element 96 extending between the end walls. As shown, the nozzle inner frame 88 may further include a plurality of transverse support elements, each indicated at 98, extending between the first longitudinal support element 94 and the second longitudinal support element 96. The nozzle inner frame 88 also directs the flow of solder through a nozzle throat defined between the first longitudinal support element 94 and the second longitudinal support element 96. The wave soldering nozzle assembly 76 further includes an elongated solder distribution baffle 100 secured to the first longitudinal support element 94 and the second longitudinal support element 96 of the nozzle inner frame 88. The solder distribution baffle 100 is secured to the first longitudinal support element 94 and the second longitudinal support element 96 with screws passing through openings provided along the sides of the solder distribution baffle. In one embodiment, the solder distribution baffle 100 includes a unique pattern of elongated openings to allow molten solder to flow through the baffle.

[0062] The wave soldering nozzle assembly further includes three solid solder nozzle plates 102a, 102b, 102c, which are fixed to corresponding connecting rods 84a, 84b, 84c and moved by corresponding actuators 80a, 80b, 80c. Each solder nozzle plate 102a, 102b, 102c is solid in construction and is configured to block the flow of molten solder when the solder nozzle plate extends below the solder distribution baffle 100. As shown, each solder nozzle plate 102a, 102b, 102c is moved by its corresponding actuator 80a, 80b, 80c to block or otherwise inhibit the flow of molten solder through the solder distribution baffle 100.

[0063] refer to Fig.16 , a solder nozzle plate (e.g., solder nozzle plate 102b) is hingedly attached to the second longitudinal support member 96 of the wave soldering nozzle assembly 76. As shown, the solder nozzle plate 102b is in an open position, in which the solder nozzle plate 102b is positioned against the second longitudinal support member 96 of the wave soldering nozzle assembly 76. Specifically, a connecting rod (e.g., connecting rod 84b) is pivotally fixed to the solder nozzle plate 102, and when the actuator (e.g., actuator 80b) is extended, the connecting rod 84b positions the solder nozzle plate 102b in the open position. In the open position, molten solder can freely flow through the solder dispensing baffle 100 to generate a solder wave 104.

[0064] refer to Fig.17 , the actuator 80b is retracted, thereby retracting the link 84b and moving the solder nozzle plate 102b to the closed position, in which the solder nozzle plate 102b is extended to the first longitudinal support member 94 of the wave solder nozzle assembly 76. As shown, the solder nozzle plate 102b is positioned adjacent to the solder dispensing baffle 100. In this position, the flow of molten solder through the solder dispensing baffle 100 is blocked or otherwise inhibited.

[0065] The result is that the solder wave can be controlled by opening and closing the solder nozzle plates 102a, 102b, 102c. For example, the solder wave can be controlled so that the solder wave extends through the solder dispensing shutter 100 in the middle of the solder dispensing shutter by closing the solder nozzle plates 102a, 102c and opening the solder nozzle plate 102b. With this arrangement, dross is also reduced because the width of the solder wave is significantly reduced. The nozzle plates 102a, 102b, 102c can be manipulated by the respective actuators 80a, 80b, 80c to a partially open position to reduce the height of the solder wave on the solder dispensing shutter 100.

[0066] Solder Pump Control Design

[0067] refer to Fig.18 and Fig.19In another embodiment, the wave soldering station 24 includes a solder pot 110 defining a reservoir 112 that is configured to contain molten solder. In one embodiment, the solder pot 110 is a box-shaped structure that supports the various components of the wave soldering station 24, including a flow conduit 114 having three chambers within the reservoir 112. The flow conduit 114 is designed to deliver pressurized molten solder to an opening or nozzle of a wave soldering nozzle assembly, generally indicated at 116. The wave soldering nozzle assembly 116 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 112. Specifically, the wave soldering nozzle assembly 116 is capable of adjusting the height and width of the solder wave when performing a wave soldering operation.

[0068] Additional references Fig. 20 , the wave soldering nozzle assembly 116 includes a nozzle inner frame 118 having two end walls 120, 122, a first longitudinal support element 124 and a second longitudinal support element 126 extending between the end walls. As shown, the nozzle inner frame 118 may further include a plurality of transverse support elements, each indicated at 128, extending between the first longitudinal support element 124 and the second longitudinal support element 126. The nozzle inner frame 118 also directs the flow of solder through a nozzle throat defined between the first longitudinal support element 124 and the second longitudinal support element 126. The wave soldering nozzle assembly 116 further includes an elongated solder distribution baffle 130 secured to the first longitudinal support element 124 and the second longitudinal support element 126 of the nozzle inner frame 118. The solder distribution baffle 130 is secured to the first longitudinal support element 124 and the second longitudinal support element 126 with screws passing through openings provided along the sides of the solder distribution baffle. In one embodiment, the solder distribution baffle 130 includes a unique pattern of elongated openings to allow molten solder to flow through the baffle.

[0069] The wave soldering station 24 further includes three pump impellers 132a, 132b, 132c positioned within the reservoir 112 of the solder pot 110 adjacent to the flow conduit 114. The pump impellers 132a, 132b, 132c pressurize the molten solder in the reservoir 112 to vertically pump the molten solder in the reservoir to the flow conduit 114 and the wave soldering nozzle assembly 116. In one embodiment, each pump impeller 132a, 132b, 132c is a centrifugal pump that is appropriately sized to pump the molten solder to the nozzle of the wave soldering nozzle assembly 116. The wave soldering nozzle assembly 116 is configured to generate a solder wave that is provided to attach components to the circuit board 12 in a manner described below, and optimizes downtime during processing.

[0070] Additional references Fig.21 and Fig. 22, the flow conduit includes three chambers 134a, 134b, 134c, each chamber including an inlet 136a, 136b, 136c connected to a corresponding pump impeller. In the example shown, pump impeller 132a is connected to chamber 134a through inlet 136a, pump impeller 132b is connected to chamber 134b through inlet 136b, and pump 132c is connected to chamber 134c through inlet 136c. Therefore, the flow of molten solder to the solder distribution baffle 130 is controlled by controlling the pump impellers 132a, 132b, 132c. The flow of molten solder through the chambers 134a, 134b, 134c can be independently controlled by controlling the pump impellers 132a, 132b, 132c.

[0071] The result is that the solder wave can be controlled by operating the pump impellers 132a, 132b, 132c. For example, the solder wave can be controlled so that the solder wave extends through the solder dispensing barrier 130 in the middle of the solder dispensing barrier by shutting off the pump impellers 132a, 132b and operating the pump impeller 132c. With this arrangement, dross is also reduced because the width of the solder wave is significantly reduced.

[0072] A variety of different controllers can perform a variety of different 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) in addition to other operations. Using data stored in an associated memory and / or storage device, the controller can execute one or more instructions stored on one or more non-transient computer-readable media, which the controller can include and / or be connected to, which can generate manipulation data. In some examples, the controller may 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 in place of a general-purpose processor, the controller uses a dedicated integrated circuit to perform at least a portion of the operations discussed above, which is customized to perform specific operations. As shown by these examples, many specific combinations of hardware and software can be used according to examples of the present disclosure to perform the operations described herein, and the present disclosure is not limited to any specific combination of hardware and software components. Examples of the present disclosure may 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.

[0073] 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.

[0074] In some embodiments, the wave soldering nozzle assembly further includes a scum box secured to the nozzle frame and configured to reduce turbulence as the solder travels back to the reservoir, thereby further reducing solder beads that may form within the reservoir.

[0075] In some embodiments, one or more nitrogen gas lines may be provided to create an inert atmosphere during the wave soldering process.

[0076] In some embodiments, the minimum contact and maximum contact may vary.

[0077] 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.

[0078] Thus, having described several aspects of at least one embodiment of the present disclosure, it will be appreciated that various changes, modifications and improvements will readily occur to those skilled in the art. Such changes, modifications and improvements are intended to be a part of the present disclosure and are intended to fall within the spirit and scope of the present disclosure. Therefore, the previous description and 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; as well as a wave soldering station coupled to the housing, the wave soldering station comprising a solder pot having a solder reservoir, a flow conduit positioned in the reservoir of the solder pot, and 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, The wave soldering nozzle assembly is configured to selectively deliver solder to multiple portions of the solder dispensing baffle to generate a solder wave having a desired width.

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

3. The wave soldering machine according to claim 2, wherein: The wave soldering nozzle assembly further includes four nozzle plates arranged along the width of the solder dispensing baffle, each nozzle plate being configured to move relative to the solder dispensing baffle between an open position and a closed position, wherein the open position allows solder to flow through the solder dispensing baffle and the nozzle plate, and the closed position inhibits solder from flowing through the solder dispensing baffle and the nozzle plate.

4. The wave soldering machine according to claim 3, wherein: The wave soldering nozzle assembly further includes an actuator for each nozzle plate, the actuator being configured to move the nozzle plate between the open position and the closed position.

5. The wave soldering machine according to claim 4, wherein: The wave soldering nozzle assembly further includes, for each nozzle plate, a tie rod configured to secure the actuator to the nozzle plate.

6. The wave soldering machine according to claim 4, wherein: The actuator is coupled to a controller to control movement of the actuator.

7. The wave soldering machine according to claim 3, wherein: The solder distribution shield and each nozzle plate each include an opening pattern to enable solder to pass through the solder distribution shield and the nozzle plates.

8. The wave soldering machine according to claim 2, wherein: The wave soldering nozzle assembly further includes three nozzle plates arranged along the width of the solder dispensing baffle, each nozzle plate being configured to rotate relative to the solder dispensing baffle between an open position and a closed position, wherein the open position allows solder to flow through the solder dispensing baffle and the nozzle plate, and the closed position inhibits solder from flowing through the solder dispensing baffle and the nozzle plate.

9. The wave soldering machine according to claim 8, wherein: The wave soldering nozzle assembly further includes an actuator for each nozzle plate, the actuator being configured to rotate the nozzle plate between the open position and the closed position.

10. The wave soldering machine according to claim 9, wherein: The wave solder nozzle assembly further includes, for each nozzle plate, a linkage configured to secure the actuator to the nozzle plate and configured to rotate the nozzle plate between the open position and the closed position.

11. The wave soldering machine according to claim 9, wherein: The actuator is coupled to a controller to control movement of the actuator.

12. The wave soldering machine according to claim 9, wherein: The solder distribution dam includes an opening pattern to enable solder to pass through the solder distribution dam.

13. The wave soldering machine according to claim 1, wherein: The wave soldering station further includes three pump impellers, which are positioned in the reservoir of the solder pot adjacent to the flow duct, and wherein the flow duct includes three chambers, each pump impeller is fluidly connected to a corresponding chamber, and the flow of solder in each of the three chambers is controlled by a corresponding pump impeller among the three pump impellers.

14. The wave soldering machine according to claim 13, wherein: Each of the three pump impellers includes a centrifugal pump to pump the solder to the wave solder nozzle assembly.

15. The wave soldering machine according to claim 13, wherein: Each of the three chambers comprises an inlet connected to a respective pump impeller.

16. The wave soldering machine according to claim 13, wherein: Each of the three pump impellers is coupled to a controller to control the flow of solder provided by the pump impeller.

17. A method of producing a solder wave having a desired width, the method comprising: delivering solder to a wave soldering nozzle assembly including a solder dispensing baffle; selectively delivering solder to portions of the solder dispensing shield to produce a solder wave having a desired width; as well as Performing a wave soldering operation on a printed circuit board.

18. The method of claim 17, further comprising selectively delivering solder to multiple portions of the solder distribution baffle by moving one of four nozzle plates, each nozzle plate being configured to move relative to the solder distribution baffle between an open position and a closed position, wherein the open position allows solder to flow through the solder distribution baffle and the nozzle plate, and the closed position prevents solder from flowing through the solder distribution baffle and the nozzle plate.

19. The method of claim 17, further comprising selectively delivering solder to multiple portions of the solder distribution baffle by rotating one of three nozzle plates, each nozzle plate being configured to rotate relative to the solder distribution baffle between an open position and a closed position, wherein the open position allows solder to flow through the solder distribution baffle and the nozzle plate, and the closed position prevents solder from flowing through the solder distribution baffle and the nozzle plate.

20. The method of claim 17, further comprising selectively delivering solder to multiple portions of the solder dispensing baffle by selectively controlling three pump impellers positioned within a reservoir of a solder tank and in fluid communication with corresponding chambers along a width of the solder dispensing baffle.

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