Wave soldering machine, and method of generating solder wave having desired width

Abstract

To provide a wave soldering machine, and a method of generating a solder wave having a desired width.SOLUTION: A wave soldering machine is configured to perform a wave soldering operation on a printed circuit board. The wave soldering machine includes a housing, a conveyor coupled to the housing, and a wave soldering station coupled to the housing. The conveyor is configured to deliver a printed circuit board through the housing. The wave soldering station includes a solder pot with a reservoir of a solder material, a flow duct positioned in the reservoir of the solder pot, and a wave soldering nozzle assembly coupled to the flow duct. The wave soldering nozzle assembly has a solder distribution baffle configured to create a solder wave. The wave soldering nozzle assembly is configured to control the width of the solder wave through the solder distribution baffle to produce a maximum width solder wave and a minimum width solder wave.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

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

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

[0004] One aspect of the 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 comprises a housing and a conveyor coupled to the housing. The conveyor is configured to deliver the printed circuit board through the housing. The wave soldering machine further comprises a wave soldering station coupled to the housing. The wave soldering station comprises a solder pot having a reservoir of solder material, a flow conduit positioned within the reservoir of the solder pot, and a wave soldering nozzle assembly coupled to the flow conduit. The wave soldering nozzle assembly has a solder distribution baffle configured to create a solder wave. The wave soldering nozzle assembly is configured to control a width of the solder wave passing through the solder distribution baffle to create a maximum width solder wave and a minimum width solder wave.

[0005] An embodiment of the wave soldering machine may further include configuring the wave soldering nozzle assembly to include a core frame supported by the flow conduit and configured to support the solder distribution baffle. The wave soldering nozzle assembly may further include at least two nozzle plates. Each nozzle plate may be configured to move relative to the solder distribution baffle between an open position in which solder flows through the solder distribution baffle and the nozzle plate and a closed position in which solder is prevented from flowing through the solder distribution baffle and the nozzle plate. The wave soldering nozzle assembly may further include, for each nozzle plate, an actuator configured to move the nozzle plate between the open and closed positions. The wave soldering nozzle assembly may further include, for each nozzle plate, a link configured to secure the actuator to the nozzle plate. The actuator may be secured to the solder pot by an actuator support. The actuator may be coupled to a controller that controls the movement of the actuator. The wave soldering nozzle assembly may further include four nozzle plates disposed along a width of the solder distribution baffle. The solder distribution baffle and each nozzle plate may include a pattern of openings that allow solder to pass through the solder distribution baffle and nozzle plate, respectively.

[0006] The wave soldering nozzle assembly may further comprise at least two nozzle plates. Each nozzle plate may be configured to rotate relative to the solder distribution baffle between an open position in which solder flows through the solder distribution baffle and the nozzle plate and a closed position in which solder is prevented from flowing through the solder distribution baffle and the nozzle plate. The wave soldering nozzle assembly may further comprise, for each nozzle plate, an actuator configured to rotate the nozzle plate between the open and closed positions. The wave soldering nozzle assembly may further comprise, for each nozzle plate, a link configured to secure the actuator to the nozzle plate and configured to rotate the nozzle plate between the open and closed positions. The actuator may be coupled to a controller that controls movement of the actuator. The wave soldering nozzle assembly may further comprise three nozzle plates disposed along a width of the solder distribution baffle. The solder distribution baffle comprises a pattern of openings that allow solder to pass through the solder distribution baffle.

[0007] The wave soldering station may further comprise at least two pump impellers positioned within the reservoir of the solder pot adjacent the flow conduit. The flow conduit may comprise at least two chambers. Each pump impeller may be in fluid communication with a respective chamber. The flow of solder within each chamber of the at least two chambers may be controlled by a respective pump impeller of the at least two pump impellers. Each pump impeller of the at least two pump impellers may comprise a centrifugal pump that pumps the 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 of the at least two chambers may include an inlet connected to a respective pump impeller. Each pump impeller of the at least two pump impellers may be coupled to a controller that controls the flow of solder provided by the pump impeller.

[0008] Another aspect of the 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 reservoir of solder material, a flow conduit positioned within the reservoir of the solder pot, and a wave soldering nozzle assembly coupled to the flow conduit. The wave soldering nozzle assembly has a solder distribution baffle configured to create a solder wave. The wave soldering nozzle assembly is configured to control the width of the solder wave passing through the solder distribution baffle to create a maximum width solder wave and a minimum width solder wave.

[0009] An embodiment of the wave soldering station may further include configuring the wave soldering nozzle assembly to further comprise a core frame supported by the flow conduit and configured to support the solder distribution baffle. The wave soldering nozzle assembly may further comprise at least two nozzle plates. Each nozzle plate may be configured to move relative to the solder distribution baffle between an open position in which solder flows through the solder distribution baffle and the nozzle plate and a closed position in which solder is prevented from flowing through the solder distribution baffle and the nozzle plate. The wave soldering nozzle assembly may further comprise, for each nozzle plate, an actuator configured to move the nozzle plate between the open and closed positions. The wave soldering nozzle assembly may further comprise, for each nozzle plate, a link configured to secure the actuator to the nozzle plate. The actuator may be secured to the solder pot by an actuator support. The actuator may be coupled to a controller to control movement of the actuator. The wave soldering nozzle assembly may further comprise four nozzle plates disposed along a width of the solder distribution baffle. The solder distribution baffle and each nozzle plate may include a pattern of openings that allow solder to pass through the solder distribution baffle and nozzle plate, respectively.

[0010] The wave soldering nozzle assembly may further comprise at least two nozzle plates. Each nozzle plate may be configured to rotate relative to the solder distribution baffle between an open position in which solder flows through the solder distribution baffle and the nozzle plate and a closed position in which solder is prevented from flowing through the solder distribution baffle and the nozzle plate. The wave soldering nozzle assembly may further comprise, for each nozzle plate, an actuator configured to rotate the nozzle plate between the open and closed positions. The wave soldering nozzle assembly may further comprise, for each nozzle plate, a link configured to secure the actuator to the nozzle plate and configured to rotate the nozzle plate between the open and closed positions. The actuator may be coupled to a controller that controls movement of the actuator. The wave soldering nozzle assembly may further comprise three nozzle plates disposed along a width of the solder distribution baffle. The solder distribution baffle may comprise a pattern of openings that allow solder to pass through the solder distribution baffle.

[0011] The wave soldering station may further comprise at least two pump impellers positioned within the reservoir of the solder pot adjacent the flow conduit. The flow conduit may comprise at least two chambers. Each pump impeller may be in fluid communication with a respective chamber. The flow of solder within each chamber of the at least two chambers may be controlled by a respective pump impeller of the at least two pump impellers. Each pump impeller of the at least two pump impellers may comprise a centrifugal pump that pumps the 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 of the at least two chambers may include an inlet connected to a respective pump impeller. Each pump impeller of the at least two pump impellers may be coupled to a controller that controls the flow of solder provided by the pump impeller.

[0012] Yet another aspect of the present disclosure relates to a method for adjusting a width of a solder wave of a wave soldering nozzle assembly of a wave soldering machine. In one embodiment, the method includes delivering solder material to a wave soldering nozzle assembly having a solder distribution baffle, adjusting the width of the solder wave with the wave soldering nozzle assembly by selectively delivering solder to portions (or parts) of the solder distribution baffle, and performing a wave soldering operation on a printed circuit board.

[0013] An embodiment of the method may further include adjusting a width of the solder wave by moving one of the at least two nozzle plates. Each nozzle plate may be configured to move relative to the solder distribution baffle between an open position in which solder flows through the solder distribution baffle and the nozzle plate and a closed position in which solder is prevented from flowing through the solder distribution baffle and the nozzle plate. The wave soldering nozzle assembly may further include, for each nozzle plate, an actuator configured to move the nozzle plate between the open and closed positions. The method may further include controlling the actuator with a controller.

[0014] Adjusting the width of the solder wave can be accomplished 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 in which solder flows through the solder distribution baffle and the nozzle plate and a closed position in which solder is prevented from flowing through the solder distribution baffle and the nozzle plate. The wave soldering nozzle assembly can further include, for each nozzle plate, an actuator configured to rotate the nozzle plate between the open and closed positions. The method can further include controlling the actuator with a controller.

[0015] Adjusting the width of the solder wave can be accomplished by selectively controlling at least two pump impellers positioned in a reservoir of a solder pot of the wave soldering station. The wave soldering station can include a flow conduit having at least two chambers. Each pump impeller can be in fluid communication with a respective chamber. The flow of solder in each chamber of the at least two chambers can be controlled by a respective pump impeller of the at least two pump impellers. Each pump impeller of the at least two pump impellers can include a centrifugal pump that pumps the molten solder to the wave soldering nozzle assembly. The at least two pump impellers can include three pump impellers. The at least two chambers can include three chambers. Each chamber of the at least two chambers can include an inlet connected to a respective pump impeller. The method can further include controlling each pump impeller of the at least two pump impellers with a controller.

[0016] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in each figure is represented by a like reference numeral. For purposes of clarity, not every component is labeled in every drawing. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view of a wave soldering machine. [Diagram 2] FIG. 2 is a side view of the wave soldering machine with the outer packaging removed to reveal the internal components of the wave soldering machine. [Diagram 3] FIG. 2 is a cross-sectional view of a wave soldering station according to one embodiment of the present disclosure. [Figure 4]FIG. 2 is a perspective view of a wave soldering station showing a printed circuit board disposed adjacent the wave soldering station. [Diagram 5] FIG. 2 is an exploded perspective view of a wave soldering station. [Figure 6] FIG. 2 is a perspective view of a wave soldering nozzle assembly of a wave soldering station. [Figure 7] FIG. 2 is an exploded perspective view of a wave soldering nozzle assembly. [Figure 8] FIG. 2 is a top view of the wave soldering nozzle assembly showing a printed circuit board disposed adjacent to the wave soldering nozzle assembly. [Figure 9] A cross-sectional view of a portion of a wave soldering nozzle assembly showing the plate of the wave soldering nozzle assembly in a closed position. [Figure 10] 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. [Figure 11] A cross-sectional view of a portion of a wave soldering nozzle assembly showing the plate of the wave soldering nozzle assembly in an open position. [Figure 12] FIG. 2 is a cross-sectional view of a wave soldering station according to another embodiment of the present disclosure. [Figure 13] FIG. 2 is a perspective view of a wave soldering station. [Figure 14] FIG. 2 is an exploded perspective view of a wave soldering station. [Figure 15] FIG. 2 is an exploded perspective view of a wave soldering nozzle assembly of the wave soldering station. [Figure 16] A cross-sectional view of a portion of a wave soldering nozzle assembly showing the plate of the wave soldering nozzle assembly in an open position. [Figure 17]A cross-sectional view of a portion of a wave soldering nozzle assembly showing the plate of the wave soldering nozzle assembly in a closed position. [Figure 18] FIG. 2 is a cross-sectional view of a wave soldering station according to another embodiment of the present disclosure. [Figure 19] FIG. 2 is a perspective view of a wave soldering station. [Figure 20] FIG. 2 is an exploded perspective view of a wave soldering station. [Figure 21] FIG. 2 is a top view of a portion of a wave soldering nozzle assembly of a wave soldering station. [Figure 22] FIG. 2 is a perspective view of a portion of a wave soldering nozzle assembly of a wave soldering station. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The disclosure is capable of other embodiments and of being practiced or carried out in various ways. Moreover, the terms and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," "having," "containing," "involving," and variations thereof herein are intended to encompass the preceding listed items and equivalents thereof as well as additional items.

[0019] Embodiments of the present disclosure relate to controlling the flow of molten solder over a nozzle to vary the width of the solder wave. One objective is to provide the ability to adjust (reduce) the width of the solder wave to reduce dross created by the solder wave. A further objective is to automate this adjustment and allow computer control to eliminate the need for human intervention when adjustments are necessary based on the product being processed.

[0020] For illustrative purposes, and with reference to FIG. 1, an embodiment of the disclosure will be described below with respect to a wave soldering machine, generally indicated at 10, used to apply solder to a printed circuit board 12. The wave soldering machine 10 is one of several machines in a printed circuit board manufacturing / assembly line. As shown, the wave soldering machine 10 includes a housing or frame 14 adapted to house the components of the machine. A conveyor 16 is arranged to deliver the 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 an inclined path (e.g., 6 degrees relative to the horizontal) along the conveyor 16 through a tunnel 18 that includes a flux application station, generally indicated at 20, and a preheat station, generally indicated at 22, to condition the printed circuit board for wave soldering. Once conditioned (i.e., heated), the printed circuit board 12 travels to a wave soldering station, generally indicated at 24, which applies solder material to the printed circuit board. A controller 26 is provided to automate the operation of several stations of the wave soldering machine 10, including, but not limited to, the flux application station 20, the preheat station 22, and the wave soldering station 24, in a known manner.

[0021] Referring to FIG. 2, the flux application station 20 is configured to apply flux to the printed circuit boards moving on the conveyor 16 through the wave soldering machine 10. The preheating station includes several preheaters (e.g., preheaters 22a, 22b, and 22c) designed to gradually increase the temperature of the printed circuit boards moving along the conveyor 16 through the tunnel 18 to prepare the printed circuit boards for the wave soldering process. As shown, and as will be described in more detail below, the wave soldering station 24 includes a wave solder nozzle assembly in fluid communication with a reservoir of solder material. A pump is provided within the reservoir to deliver the molten solder material from the reservoir to the wave soldering nozzle assembly. Once soldered, the printed circuit boards exit the wave soldering machine 10 via the conveyor 16 to another station in the manufacturing line, such as a pick-and-place machine.

[0022] In some embodiments, the wave soldering machine 10 may further include a flux management system, generally indicated at 28, that removes volatile contaminants from the tunnel 18 of the wave soldering machine. As shown in FIG. 2, the flux management system 28 is located below the preheat station 22. In one embodiment, the flux management system is supported by the housing 14 within the wave soldering machine and in fluid communication with the tunnel 18, which is shown diagrammatically in FIG. 2. The flux management system 28 is configured to receive contaminated gas from the tunnel 18, treat the gas, and return clean gas to the tunnel. The flux management system 28 is particularly configured to remove volatile contaminants from the gas, particularly in an inert atmosphere.

[0023] The embodiments of the present disclosure relate to minimizing dross associated with molten solder. Different combinations of tin, lead, and other metals are used to make lead-based and lead-free solders. Dross is a mass of solid impurities floating on the surface of the molten solder or dispersed within the molten solder. In the case of solder, dross tends to form on the surface of the molten metal, which is tin-based, and oxidized impurities create the dross.

[0024] Sliding solder nozzle plate design 3 and 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 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 more detail below, the wave soldering nozzle assembly 36 is configured to convey the molten solder to the bottom of the printed circuit board 12 and allows for a smooth flow of the solder back to the reservoir 32. In particular, the wave soldering nozzle assembly 36 is capable of adjusting the height and width of the solder wave when performing a wave soldering operation.

[0025] The wave soldering station 24 further includes a pump impeller 38 positioned within the reservoir 32 of the solder pot 30 adjacent an inlet provided within the flow conduit 34. The pump impeller 38 pressurizes the molten solder within the reservoir 32 and pumps the molten solder vertically within the reservoir to the wave soldering nozzle assembly 36. In one embodiment, the pump impeller 38 is a centrifugal pump that is suitably sized to pump the molten solder to the nozzle of the wave soldering nozzle assembly 36. The wave soldering nozzle assembly 36 is configured to generate the solder wave provided for attaching components onto the circuit board 12 in the methods described herein and to optimize dwell time during processing.

[0026] 5 and 6, the wave soldering nozzle assembly 36 is coupled to four actuators, namely actuators 40a, 40b, 40c, 40d, for variably adjusting the width of the solder wave during a wave soldering operation to increase or decrease the contact length of the solder wave. The actuators 40a, 40b, 40c, 40d are secured to the solder pot 30 by an actuator support frame 42, which is secured to a side wall of the solder pot by suitable fasteners such as bolts. The actuator support frame 42 may alternatively be secured to the solder pot 30 in another manner, such as by welding. As shown, the actuators 40a, 40b, 40c, 40d are secured to the actuator support frame 42, which is configured to rigidly support the actuators relative to the solder pot 30. The actuators 40a, 40b, 40c, 40d are positioned next to the wave soldering nozzle assembly 36 and form part of an assembly for adjusting the nozzle of the wave soldering nozzle assembly by respective connecting links 44a, 44b, 44c, 44d that are coupled to the respective actuators to provide movement for variably adjusting the nozzle opening width of the wave soldering nozzle assembly. In a particular embodiment, each actuator 40a, 40b, 40c, 40d includes an electromechanical actuator that provides movement for adjusting the nozzle opening width. The actuators 40a, 40b, 40c, 40d incorporate encoders that are driven by computerized machine software (supported by the controller 26) and can relay position indications to the machine software.

[0027] 7 and 8, the wave soldering nozzle assembly 36 includes a nozzle core 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 core frame 48 may further include a number of cross support elements, each indicated at 58, extending between the first longitudinal support element 54 and the second longitudinal support element 56. The nozzle core frame 48 also directs 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 core 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 or load side 64 of the solder distribution baffle 60 is secured to or formed integrally with the first longitudinal support element 54 and the opposite side or discharge side 66 of the solder distribution baffle is secured to or formed integrally with the second longitudinal support element 56. In one embodiment, the solder distribution baffle 60 includes a unique pattern of elongated openings that allow molten solder to flow through the baffle.

[0028] The wave soldering nozzle assembly 36 further comprises four solder nozzle plates 62a, 62b, 62c, 62d secured to respective links 44a, 44b, 44c, 44d and moved by respective actuators 40a, 40b, 40c, 40d. Each solder nozzle plate 62a, 62b, 62c, 62d comprises the same unique pattern of elongated apertures. The unique hole pattern design incorporated into the solder distribution baffle and solder nozzle plate creates a uniform parallel wave across the entire solder contact area while maintaining a 6 degree liquid molten solder plane parallel to the 6 degree plane of the conveyor 16 carrying the circuit board 12. As shown, each solder nozzle plate 62a, 62b, 62c, 62d is moved by its respective actuator 40a, 40b, 40c, 40d to control the flow of molten solder through the solder distribution baffle 60 and the solder nozzle plate.

[0029] In some embodiments, the wave soldering nozzle assembly 36 further comprises a dross box secured to the nozzle frame and configured to reduce solder balls that may form in the reservoir by reducing turbulence as the solder returns to the reservoir 32. One or more nitrogen tubes may be provided to create an inert atmosphere during the wave soldering process.

[0030] 9 shows a solder nozzle plate, for example solder nozzle plate 62a, in a fully extended position such that the solder nozzle plate nearly completely overlaps solder distribution baffle 60, thereby preventing molten solder from flowing through the nozzle. As shown, the flow of molten solder is prevented from passing through solder distribution baffle 60.

[0031] 10 illustrates a solder nozzle plate, for example, solder nozzle plate 62c, in a first partially extended position such that the solder nozzle plate partially overlaps the solder distribution baffle 60 and partially allows molten solder to flow through the nozzle. As shown, the flow of molten solder can partially pass through the solder distribution baffle 60 and the solder nozzle plate 62c. The printed circuit board 12 passing over the solder wave 64 has minimal contact with the solder wave 64.

[0032] 11 illustrates a solder nozzle plate, e.g., solder nozzle plate 62b and / or solder nozzle plate 62d (as shown), in a second partially extended position such that the solder nozzle plate barely overlaps the solder distribution baffle, allowing the molten solder to flow completely through the nozzle. As shown, the flow of molten solder can pass completely through the solder distribution baffle 60 and the solder nozzle plate 62d. The printed circuit board 12 passing over the solder wave 66 makes maximum contact with the solder wave 66.

[0033] As a result, the solder wave can be controlled by opening and closing solder nozzle plates 62a, 62b, 62c, 62d. For example, by closing solder nozzle plates 62a, 62d and opening solder nozzle plates 62b, 62c, the solder wave can be controlled such that the solder wave extends through solder distribution baffle 60 at the middle of the solder distribution baffle. This setup significantly reduces the width of the solder wave, thereby reducing dross.

[0034] Flow Throttle Design 12 and 13, in another embodiment, the wave soldering station 24 includes a solder pot 70 that defines a reservoir 72 configured to contain molten solder. In one embodiment, the solder pot 70 is a box-shaped structure that supports the 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 designated 76. The wave soldering nozzle assembly 76 is configured to convey the molten solder to the bottom of the printed circuit board 12 and allows for a smooth flow of the solder back to the reservoir 72. In particular, the wave soldering nozzle assembly 76 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 78 positioned within the reservoir 72 of the solder pot 70 adjacent an inlet provided within the flow conduit 74. The pump impeller 78 pressurizes the molten solder within the reservoir 72 and pumps the molten solder vertically within the reservoir to a wave soldering nozzle assembly 76. In one embodiment, the pump impeller 78 is a centrifugal pump that is suitably 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 the solder wave provided for attaching components onto the circuit board 12 in the methods described herein and to optimize dwell time during processing.

[0036] 14 and 15, the wave soldering nozzle assembly 76 is coupled to three actuators, namely actuators 80a, 80b, and 80c, which disrupt the flow of molten solder to portions of the wave soldering nozzle assembly. The actuators 80a, 80b, and 80c are secured to the solder pot 70 by an actuator support frame 82, which is secured to a sidewall of the solder pot 70 by suitable fasteners, such as bolts. The actuator support frame 82 may alternatively be secured to the solder pot 70 in another manner, such as by welding. As shown, the actuators 80a, 80b, and 80c are secured to the actuator support frame 82, which is configured to rigidly support the actuators relative to the solder pot 70. The actuators 80a, 80b, 80c are positioned next to the wave soldering nozzle assembly 76 and form part of an assembly for adjusting the nozzle of the wave soldering nozzle assembly by respective connecting links 84a, 84b, 84c which are coupled to the respective actuators. In a particular embodiment, each actuator 80a, 80b, 80c includes an electromechanical actuator that provides movement to adjust the nozzle opening width. The actuators 80a, 80b, 80c incorporate encoders that are driven by computerized machine software (supported by the controller 26) and can relay position indications to the machine software.

[0037] The wave soldering nozzle assembly 76 includes a nozzle core 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 core frame 88 may further include a number 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 core frame 88 also directs solder flow 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 core frame 88. The solder distribution baffle 100 is secured to the first and second longitudinal support elements 94, 96 with screws that pass through openings along the sides of the solder distribution baffle. In one embodiment, the solder distribution baffle 100 includes a unique pattern of elongated openings that allow molten solder to flow through the baffle.

[0038] The wave soldering nozzle assembly further comprises three solid solder nozzle plates 102a, 102b, 102c secured to respective links 84a, 84b, 84c and moved by respective actuators 80a, 80b, 80c. Each solder nozzle plate 102a, 102b, 102c is solid in structure and configured to block the flow of molten solder when extended beneath the solder distribution baffle 100. As shown, each solder nozzle plate 102a, 102b, 102c is moved by its respective actuator 80a, 80b, 80c to block or otherwise inhibit the flow of molten solder through the solder distribution baffle 100.

[0039] 16, a solder nozzle plate, e.g., solder nozzle plate 102b, is hingedly attached to the second longitudinal support element 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 element 96 of the wave soldering nozzle assembly 76. Specifically, a link, e.g., link 84b, is pivotally secured to the solder nozzle plate 102, and when an actuator, e.g., actuator 80b, is extended, the link 84b positions the solder nozzle plate 102b in the open position. In the open position, molten solder is free to flow through the solder distribution baffle 100, creating a solder wave 104.

[0040] 17, actuator 80b is retracted, which in turn retracts link 84b and moves solder nozzle plate 102b to a closed position in which solder nozzle plate 102b extends to first longitudinal support element 94 of wave soldering nozzle assembly 76. As shown, solder nozzle plate 102b is positioned adjacent solder distribution baffle 100. In this position, molten solder is shielded or otherwise prevented from flowing through solder distribution baffle 100.

[0041] As a result, the solder wave can be controlled by opening and closing the solder nozzle plates 102a, 102b, 102c. For example, by closing the solder nozzle plates 102a, 102c and opening the solder nozzle plate 102b, the solder wave can be controlled such that the wave extends through the solder distribution baffle 100 at the middle of the solder distribution baffle. This setting significantly reduces the width of the solder wave, thereby reducing dross. The nozzle plates 102a, 102b, 102c can be manipulated by respective actuators 80a, 80b, 80c to achieve a partially open position and reduce the height of the solder wave on the solder distribution baffle 100.

[0042] Solder Pump Control Design 18 and 19, in another embodiment, the wave soldering station 24 includes a solder pot 110 that defines a reservoir 112 configured to contain molten solder. In one embodiment, the solder pot 110 is a box-shaped structure that supports the 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 designated 116. The wave soldering nozzle assembly 116 is configured to convey the molten solder to the bottom of the printed circuit board 12 and allows for a smooth flow of the solder back to the reservoir 112. In particular, the wave soldering nozzle assembly 116 is capable of adjusting the height and width of the solder wave when performing a wave soldering operation.

[0043] 20, the wave soldering nozzle assembly 116 includes a nozzle core 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 core frame 118 may further include a number 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 core frame 118 also directs solder flow 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 core frame 118. The solder distribution baffle 130 is secured to the first and second longitudinal support elements 124, 126 with screws that pass through openings along the sides of the solder distribution baffle. In one embodiment, the solder distribution baffle 130 includes a unique pattern of elongated openings that allow molten solder to flow through the baffle.

[0044] The wave soldering station 24 further comprises three pump impellers 132a, 132b, 132c positioned within the reservoir 112 of the solder pot 110 adjacent the flow conduit 114. The pump impellers 132a, 132b, 132c pressurize the molten solder within the reservoir 112 and pump the molten solder vertically within the reservoir to the flow conduit 114 and to the wave soldering nozzle assembly 116. In one embodiment, each pump impeller 132a, 132b, 132c is a centrifugal pump that is suitably 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 for attaching components onto the circuit board 12 in a manner described below, as well as to optimize dwell time during processing.

[0045] 21 and 22, the flow conduit includes three chambers 134a, 134b, 134c, each with an inlet 136a, 136b, 136c connected to a respective pump impeller. In the illustrated example, pump impeller 132a is connected to chamber 134a by inlet 136a, pump impeller 132b is connected to chamber 134b by inlet 136b, and pump 132c is connected to chamber 134c by inlet 136c. Thus, the flow of molten solder into the solder distribution baffle 130 is controlled by controlling pump impellers 132a, 132b, 132c. The flow of molten solder through chambers 134a, 134b, 134c can be independently controlled by controlling pump impellers 132a, 132b, 132c.

[0046] As a result, by operating pump impellers 132a, 132b, 132c, the solder wave can be controlled. For example, by shutting off pump impellers 132a, 132b and operating pump impeller 132c, the solder wave can be controlled such that the wave extends through solder distribution baffle 130 at the middle of the solder distribution baffle. This setup significantly reduces the width of the solder wave, thereby reducing dross.

[0047] Various 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, among other operations. Using data stored in associated memory and / or storage, the controller can execute one or more instructions stored in one or more non-transitory computer-readable media that the controller may comprise and / or be coupled to, which may result in the data being manipulated. In some examples, the controller can include one or more processors or other types of controllers. In one example, the controller is or includes at least one processor. In another example, the controller performs at least a portion of the operations discussed above using application specific integrated circuits tailored to perform specific operations in addition to or instead of a general purpose processor. As illustrated by these examples, examples according to the present disclosure can perform the operations described herein using many specific combinations of hardware and software, and the present disclosure is not limited to any particular combination of hardware and software components. Examples of the present disclosure can include computer program products configured to perform the methods, processes, and / or operations discussed above. The computer program product may be or may include one or more controllers and / or processors configured to execute instructions for performing the methods, processes, and / or operations discussed above.

[0048] According to the embodiments, the solder flow through the nozzle can be controlled to reduce or even prevent recirculation of dross through the nozzle.Dross is reduced by reducing the width of the solder wave. According to the embodiments, the width of the solder wave can be reduced.

[0049] In some embodiments, the wave soldering nozzle assembly further comprises a dross box secured to the nozzle frame and configured to further reduce solder balls that may form in the reservoir by reducing disturbances as the solder returns to the reservoir.

[0050] In some embodiments, one or more nitrogen tubes may be provided to create an inert atmosphere during the wave soldering process.

[0051] In some embodiments, the minimum and maximum contact can be varied.

[0052] As used herein, "solder wave width" describes the cross-sectional dimension of the actual solder wave, and "contact length" describes the distance on the PCB that is in contact with the wave at any given time. As used herein, the term "length" refers to the contact length parallel to the direction of PCB movement.

[0053] Having thus described several aspects of at least one embodiment of the present disclosure, it should be understood that various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of this disclosure. Accordingly, the foregoing description and drawings are by way of example only.

Claims

1. 1. A wave soldering machine for performing a wave soldering operation on a printed circuit board, comprising: Housing and a conveyor coupled to the housing and configured to deliver a printed circuit board through the housing; a wave soldering station coupled to the housing, the wave soldering station including a solder pot having a reservoir of solder material, a flow conduit positioned within the reservoir of the solder pot, and a wave soldering nozzle assembly coupled to the flow conduit, the wave soldering nozzle assembly having a solder distribution baffle configured to produce a solder wave; Equipped with the wave soldering nozzle assembly is configured to selectively deliver solder material to multiple portions of the solder distribution baffle to create a solder wave having a desired width; Wave soldering machine.

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

3. 3. The wave soldering machine of claim 2, wherein the wave soldering nozzle assembly further includes four nozzle plates disposed along a width of the solder distribution baffle, each nozzle plate configured to move relative to the solder distribution baffle between an open position in which solder material flows through the solder distribution baffle and the nozzle plate, and a closed position in which solder material is prevented from flowing through the solder distribution baffle and the nozzle plate.

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

5. The wave soldering machine of claim 4 , wherein the wave soldering nozzle assembly further comprises, for each nozzle plate, a link configured to secure the actuator to the nozzle plate.

6. The wave soldering machine of claim 4 , wherein the actuator is coupled to a controller that controls movement of the actuator.

7. 4. The wave soldering machine of claim 3, wherein the solder distribution baffle and each nozzle plate includes a pattern of openings that allow solder material to pass through the solder distribution baffle and each nozzle plate, respectively.

8. 3. The wave soldering machine of claim 2, wherein the wave soldering nozzle assembly further includes three nozzle plates disposed along a width of the solder distribution baffle, each nozzle plate configured to rotate relative to the solder distribution baffle between an open position in which solder material flows through the solder distribution baffle and the nozzle plate, and a closed position in which solder material is prevented from flowing through the solder distribution baffle and the nozzle plate.

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

10. 10. The wave soldering machine of claim 9, wherein the wave soldering nozzle assembly further includes, for each nozzle plate, a link 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 of claim 9 , wherein the actuator is coupled to a controller that controls the movement of the actuator.

12. 10. The wave soldering machine of claim 9, wherein the solder distribution baffle includes a pattern of openings that allow solder material to pass through the solder distribution baffle.

13. 2. The wave soldering machine of claim 1, wherein the wave soldering station further includes three pump impellers positioned within the reservoir of the solder pot adjacent to the flow conduit, the flow conduit including three chambers, each pump impeller in fluid communication with a respective chamber, and a flow of solder material within each of the three chambers being controlled by a respective one of the three pump impellers.

14. 14. The wave soldering machine of claim 13, wherein each pump impeller of the three pump impellers includes a centrifugal pump that pumps the solder material to the wave soldering nozzle assembly.

15. 14. The wave soldering machine of claim 13, wherein each of the three chambers includes an inlet connected to a respective pump impeller.

16. 14. The wave soldering machine of claim 13, wherein each pump impeller of the three pump impellers is coupled to a controller that controls the flow of solder material provided by the pump impeller.

17. 1. A method for producing a solder wave having a desired width, comprising: Delivering solder material to a wave soldering nozzle assembly including a solder distribution baffle; selectively delivering solder material to portions of the solder distribution baffle to create a solder wave having a desired width; performing a wave soldering operation on the printed circuit board; A method comprising:

18. 18. The method of claim 17, further comprising selectively delivering solder material to multiple portions of the solder distribution baffle by moving one of four nozzle plates, each nozzle plate configured to move relative to the solder distribution baffle between an open position in which solder material flows through the solder distribution baffle and the nozzle plate, and a closed position in which solder material is prevented from flowing through the solder distribution baffle and the nozzle plate.

19. 18. The method of claim 17, further comprising selectively delivering solder material to multiple portions of the solder distribution baffle by rotating one of three nozzle plates, each nozzle plate configured to rotate relative to the solder distribution baffle between an open position in which solder material flows through the solder distribution baffle and the nozzle plate, and a closed position in which solder material is prevented from flowing through the solder distribution baffle and the nozzle plate.

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

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