Stencil printer squeegee drip collection system

Abstract

The squeegee drip collection system is configured to receive assembly material from at least one squeegee blade of the printhead assembly. The squeegee drip collection system includes a paste shield coupled to the printhead gantry, the paste shield configured to be moved between a retracted position in which the paste shield is spaced apart from the at least one squeegee blade and an extended position in which the paste shield is positioned beneath the at least one squeegee blade. The squeegee drip collection system further includes a paste shield removal assembly configured to decouple the paste shield from the printhead gantry and remove the paste shield.

Description

[Technical field]

[0001] Related Applications This application is related to U.S. patent application Ser. No. (blank) by Pasty A. Mattero and Steven R. Foster, entitled “COMPONENT LOADING VERIFICATION SYSTEM AND METHOD,” filed on even date herewith, which is hereby incorporated by reference in its entirety for all purposes.

[0002] Background of the disclosure 1. Field of the invention This application relates generally to stencil printers and related methods for printing viscous materials, such as solder paste, onto electronic substrates, such as printed circuit boards (PCBs), and more specifically to systems and methods for capturing and containing excess material that drips from a squeegee blade during operation. [Background technology]

[0003] 2. Description of Related Technology In manufacturing surface mount printed circuit boards, a stencil printer can be used to print solder paste onto the circuit board. Typically, a circuit board having a pattern of pads or some other conductive surface onto which the solder paste is to be deposited is automatically fed into the stencil printer, which uses one or more small holes or marks (known as "fiducials") on the circuit board to properly align the circuit board with the stencil or screen of the stencil printer before printing the solder paste onto the circuit board. In some systems, an optical alignment system embodying a vision system is used to align the circuit board with the stencil.

[0004] In such printers, once the circuit board is properly aligned with the stencil, it is raised up to the stencil and solder paste is dispensed onto the stencil. A wiper blade (or squeegee) moves across the stencil, forcing the solder paste through the holes in the stencil and onto the circuit board. As the squeegee moves across the stencil, the solder paste tends to spread out in front of the blade. This desirably causes mixing and shearing of the solder paste to obtain a desired viscosity to facilitate filling the holes in the screen or stencil. The solder paste is typically dispensed onto the stencil from a standard cartridge. The stencil is then separated from the circuit board, with the majority of the material remaining on the circuit board due to the adhesion between the circuit board and the solder paste. The material left on the bottom surface of the stencil is removed in a cleaning process before more circuit boards are printed.

[0005] One problem is preventing solder paste from dripping off the squeegee blade and contaminating the operating workspace during operation. During operation, solder paste can inadvertently drip off the squeegee blade as it traverses the stencil printer and fall onto the stencil or electronic board support. Summary of the Invention

[0006] Disclosure Summary One aspect of the disclosure is directed to a stencil printer for printing assembly material onto an electronic substrate. In one embodiment, the stencil printer comprises a frame, a stencil coupled to the frame and having holes formed therein, and a support assembly coupled to the frame and configured to support the electronic substrate. The stencil printer further comprises a printhead gantry coupled to the frame, a printhead assembly supported by the printhead gantry such that the printhead assembly is configured to traverse the stencil during a printing stroke, and a squeegee drip collection system configured to receive assembly material from at least one squeegee blade of the printhead assembly. The squeegee drip collection system comprises a paste shield coupled to the printhead gantry, the paste shield configured to be moved between a retracted position in which the paste shield is spaced apart from the at least one squeegee blade and an extended position in which the paste shield is positioned beneath the at least one squeegee blade. The squeegee drip collection system further comprises a paste shield removal assembly configured to decouple the paste shield from the printhead gantry and remove the paste shield.

[0007] The embodiment of the stencil printer may further include a paste shield having a flat bottom wall, a front wall, a rear wall, and two side walls that create a shallow receptacle that receives solder paste from the at least one squeegee blade. The print head gantry may include an elongated beam supported along rails provided on the frame. The elongated beam of the print head gantry may include at least one horizontally extending linear bearing. The paste shield removal assembly may include at least one tooling member configured to move laterally on the at least one linear bearing. The at least one tooling member may include a downwardly extending pin having an end configured to be received within a receiving feature associated with the paste shield. The paste shield may include at least one receiving feature configured to engage the paste shield and be engaged by the pin of the at least one tooling member to move the paste shield. The at least one tooling member may include two spaced apart tooling members each having a pin, the first tooling member configured to move laterally on a first linear bearing and the second tooling member configured to move laterally on a second linear bearing. The at least one storage feature may include two storage features, one for each tooling member, the first tooling member and the second tooling member stored within the respective storage features of the paste shield to releasably secure the paste shield. The squeegee drip collection assembly may further include at least one extension mechanism configured to move the paste shield between a retracted position and an extended position. The at least one extension mechanism may include a bracket secured to the printhead gantry and an extension member mounted on the bracket. The extension member may include a cylinder mounted to the bracket and a rod reciprocally received in the piston. Each rod may have an end that is stored within at least one storage feature of the paste shield.The paste shield may be configured with a spring-loaded locking mechanism to secure the paste shield to the at least one extension mechanism within the at least one storage feature. The stencil printer may further include a controller coupled to the printhead gantry, the printhead assembly, and the squeegee drip collection system. The controller may be configured to control movement of the paste shield between the retracted position and the extended position and to perform an operation to replace the paste shield.

[0008] Another aspect of the disclosure is directed to a method of removing a paste shield configured to retrieve assembly material from a squeegee of a printhead gantry. In one embodiment, the method includes positioning at least one tooling member adjacent to at least one storage feature of the paste shield, moving the paste shield toward the at least one tooling member with at least one extension mechanism, positioning the at least one tooling member within the at least one storage feature of the paste shield to release the paste shield from the at least one extension mechanism, and supporting the paste shield with the at least one tooling member.

[0009] An embodiment of the method further includes positioning at least one tooling member in the at least one storage feature, including positioning a downwardly extending pin of the at least one tooling member in the storage feature and triggering a spring-loaded locking mechanism to release the paste shield from the at least one extension mechanism. The at least one tooling member may include two spaced apart tooling members each having a pin. The at least one storage feature may include two storage features, the two tooling members being stored in respective storage features of the paste shield to secure the paste shield. The at least one extension mechanism may include a bracket secured to the printhead gantry and an extension member mounted on the bracket. The at least one extension member may include a cylinder mounted to the bracket and a rod reciprocally received in a piston, each rod having a head stored in a storage feature of the paste shield. The paste shield may be configured with a spring-loaded locking mechanism to secure the paste shield to the at least one extension mechanism.

[0010] Yet another aspect of the present disclosure is directed to a squeegee drip collection system configured to receive assembly material from at least one squeegee blade of a printhead assembly. The squeegee drip collection system includes a paste shield coupled to the printhead gantry, the paste shield configured to be moved between a retracted position in which the paste shield is spaced apart from the at least one squeegee blade and an extended position in which the paste shield is positioned beneath the at least one squeegee blade. The squeegee drip collection system further includes a paste shield removal assembly configured to decouple the paste shield from the printhead gantry and remove the paste shield.

[0011] BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like reference numeral. For clarity, every component may not be labeled in every drawing. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a front view of the stencil printer. [Diagram 2] FIG. 2 is a front perspective view of the stencil printer. [Diagram 3] FIG. 3 is a top view of the stencil printer shown in FIG. 2 with a portion removed. [Figure 4] FIG. 1 is a perspective view of a printhead assembly according to one embodiment of the present disclosure. [Diagram 5] FIG. 2 is a perspective view of a printhead assembly having a tooling member configured to engage a paste shield provided on a support. [Figure 6] FIG. 6 is an enlarged perspective view of a tooling member of the printhead assembly shown in FIG. [Figure 7] FIG. 13 is a top perspective view of a tooling member engaging a paste shield, where a push pin is used to move the paste shield. [Figure 8] FIG. 8 is a bottom perspective view of a tooling member that engages the paste shield shown in FIG. [Figure 9] FIG. 13 is a perspective view of a tooling member supporting a paste shield. [Figure 10] FIG. 13 is an enlarged perspective view of a push pin configured to engage the paste shield. [Figure 11] FIG. 13 is an enlarged perspective view of a tooling member supporting the paste shield; [Figures 12A-12C] FIG. 13 shows an embodiment of a paste shield. [Figures 13A-13C] FIG. 13 shows an embodiment of a push pin. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Detailed Description of the Disclosure The present disclosure generally relates to material dispensing machines (referred to in this disclosure as "stencil printers," "screen printers," "printers," or "printers") and other equipment utilized in surface mount technology (SMT) process lines and configured to dispense assembly materials (e.g., solder paste, conductive ink, or encapsulant material) onto substrates (e.g., printed circuit boards, referred to in this disclosure as "electronic boards," "circuit boards," "boards," "PCBs," "PCB boards," "substrates," or "PCB plates") or to perform other operations such as inspection, rework, or placement of electronic components onto the substrates. Specifically, embodiments of the present disclosure are described below with reference to stencil printers used to make printed circuit boards.

[0014] For purposes of illustration only and not limitation of generality, the present disclosure will now be described in detail with reference to the accompanying drawings. The present disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The principles described in the present disclosure can be used in other embodiments and can be practiced or carried out in various ways. Additionally, the phraseology and terminology used in the present disclosure are for the purpose of description and should not be considered as limiting. Any reference to an example, embodiment, component, element, or operation of a system or method referred to in the present disclosure as singular can also encompass embodiments including the plural, and any reference to any embodiment, component, element, or operation in the present disclosure as plural can also encompass embodiments including only the singular. References in the singular or plural are not intended to limit the systems or methods disclosed in the present disclosure, their components, operations, or elements. The use of the terms "including," "comprising," "having," "containing," "with," and variations thereof in the present disclosure are meant to encompass the items listed therein, as well as equivalents and additional items. References to "or" can be construed as inclusive such that any term described with "or" can refer to any one, more than one, and all of the described term. Additionally, in the event of an inconsistency in the usage of a term between this disclosure and a document incorporated by reference, the usage of the term in the document incorporated by reference is supplementary to the usage of this disclosure, and in the event of an inconsistency resulting in a conflict, the usage of the term in this disclosure will control.

[0015] The embodiments of the present disclosure are described below with reference to a stencil printer used to print assembly materials, such as solder paste, onto a circuit board. However, one skilled in the art will appreciate that the embodiments of the present disclosure are not limited to stencil printers that print solder paste onto a circuit board, but can be used in other applications requiring the dispensing of other viscous assembly materials, such as glues and encapsulants. For example, the device can be used to print epoxies used as underfills for chip-scale packages. Furthermore, stencil printers according to embodiments of the present disclosure are not limited to those that print assembly materials onto circuit boards, but include those used to print other materials onto various substrates, such as semiconductor wafers. Additionally, the terms screen and stencil can be used interchangeably in this disclosure to describe devices within the printer that define the pattern printed onto the substrate. In certain embodiments, the stencil printer can include a Momentum™ or Edison™ series stencil printer platform provided by ITW Electronic Assembly Equipment, Hopkinton, Massachusetts. An exemplary stencil printer is generally designated 5 in FIG. 1. In this embodiment, the stencil printer 5 is a Momentum™ series stencil printer platform provided by ITW Electronic Assembly Equipment, Inc. of Hopkinton, Massachusetts.

[0016] 2, a stencil printer according to an embodiment of the present disclosure is generally indicated at 10. As shown, the stencil printer 10 has a frame 12 that supports the components of the stencil printer, which may include, in part, a controller 14, a display 16, a stencil 18, and a printhead or printhead assembly. The printhead or printhead assembly is generally indicated at 20 and is configured to apply solder paste in a manner that will be described in more detail below.

[0017] As shown in FIG. 2 and described below, the stencil and printhead assembly may be coupled or otherwise connected to frame 12 as appropriate. In one embodiment, printhead assembly 20 may be mounted on a printhead assembly gantry, generally indicated at 22 and sometimes referred to as a “printhead gantry,” which may be mounted on frame 12. Printhead assembly 20 includes a printhead having a squeegee blade configured to move across stencil 18 during a printing operation. In particular, the printhead is configured to eject solder paste (or another viscous material) onto stencil 18, and the squeegee blade is configured to force the solder paste through holes formed in the stencil. Printhead gantry 22 allows printhead assembly 20 to move in the y-axis direction under the control of controller 14 and to apply pressure to the squeegee blade of the printhead assembly by engaging stencil 18. In one particular embodiment, the printhead assembly 20 can be placed over the stencil 18 and lowered in the z-axis direction into contacting and sealing engagement with the stencil.

[0018] The stencil printer 10 may also have a conveyor system having rails (not shown) that transport printed circuit boards (sometimes referred to in this disclosure as "printed wiring boards," "boards," or "electronic boards") to a printing position within the stencil printer. The rails may sometimes be referred to in this disclosure as a "tractor feed mechanism." The tractor feed mechanism is configured to feed, load, or otherwise deliver the circuit boards to and from a work area of ​​the stencil printer, sometimes referred to in this disclosure as a "print nest."

[0019] 3, the stencil printer 10 includes a support assembly 28 that supports a circuit board 29 (shown in dashed lines). The support assembly 28 elevates and secures the circuit board so that it is stable during the printing operation. In certain embodiments, the substrate support assembly 28 can further include a substrate support system, such as a rigid support, multiple pins, or flexible tooling, that is positioned below the circuit board when the circuit board is in the printing position. The substrate support system can be used in part to support an interior area of ​​the circuit board to prevent bending or warping of the circuit board during the printing operation.

[0020] In one embodiment, the printhead assembly 20 can be configured to receive solder paste from a supply, such as a dispenser, e.g., a solder paste cartridge, that provides the solder paste to the printhead assembly during a printing operation. Other methods of supplying solder paste may be utilized instead of a cartridge. For example, the solder paste may be manually deposited between the blades or from an external source. Additionally, in certain embodiments, the controller 14 can be configured to control the operation of the stencil printer 10 using application specific software using a personal computer having a suitable operating system, such as the Microsoft Windows operating system provided by Microsoft Corporation. The controller 14 can be networked with a master controller used to control a production line that fabricates the circuit boards.

[0021] In one configuration, the stencil printer 10 operates as follows: A circuit board 29 is loaded into the stencil printer 10 using the conveyor rails. The support assembly 28 raises and secures the circuit board 29 in a printing position. The printhead assembly 20 is then lowered in the z-axis until the blades of the printhead assembly contact the stencil 18 with the desired pressure. The printhead assembly 20 is then moved in the y-axis across the stencil 18 by the printhead gantry 22. The printhead assembly 20 deposits solder paste onto the circuit board 29 through the holes in the stencil 18. Once the printhead assembly has completely traversed the stencil 18 across the holes, the printhead assembly is lifted off the stencil and the circuit board 29 is lowered back onto the conveyor rails. The circuit board 29 is released and transported from the stencil printer 10 so that a second circuit board can be loaded into the stencil printer. To print on the second circuit board 29, the printhead assembly is lowered in the z-axis direction into contact with the stencil and moved across the stencil 18 in the opposite direction to that used for the first circuit board.

[0022] An imaging system 30 may be provided for the purpose of aligning the stencil 18 with respect to the circuit board 29 before printing and inspecting the circuit board after printing. In one embodiment, the imaging system 30 may be disposed between the stencil 18 and the support assembly 28 on which the circuit board is supported. The imaging system 30 is coupled to an imaging gantry 32 for moving the imaging system. In one embodiment, the imaging gantry 32 may be coupled to the frame 12 and have a beam extending between the side rails of the frame 12 to provide back and forth movement of the imaging system 30 above the circuit board 29 in the y-axis direction. The imaging gantry 32 may further include a carriage device configured to house the imaging system 30 and move along the length of the beam in the x-axis direction. The structure of the imaging gantry 32 used to move the imaging system 30 is known in the art of solder paste printing. The arrangement is such that the imaging system 30 may be located anywhere below the stencil 18 and above the circuit board 29 to capture images of predetermined areas of the circuit board or stencil, respectively.

[0023] After one or more applications of solder paste to the circuit board, excess solder paste may accumulate on the bottom of the stencil 18 and a stencil wiper assembly, generally indicated at 34, may move underneath the stencil to remove the excess solder paste. In other embodiments, the stencil 18 may move over the stencil wiper assembly.

[0024] Referring to FIG. 4, the printhead assembly 20 is mounted on a printhead gantry 22 that provides movement in the y-axis direction under the control of the controller 14. The printhead gantry 22 includes an elongated beam 36 supported along rails 38, 40 (FIG. 3) that are provided on the frame 12 of the stencil printer 10. The beam 36 includes a plate 42 having two horizontally extending groups of linear bearings 44, 46, with top linear bearings 44a, 44b positioned above bottom linear bearings 46a, 46b. The purpose of the linear bearings 44a, 44b, 46a, 46b will be explained in more detail below. The printhead assembly 20 includes a printhead 48 that is coupled to the beam 36 of the printhead gantry 22. Specifically, the printhead 48 is mounted on a carriage 50 that is fixedly mounted on the plate 42. The printhead gantry 22 thus provides movement of the printhead 48 in the y-axis direction to perform print strokes as described in this disclosure. The print head 48 includes a squeegee blade (shown at 52) ​​that spreads the solder paste over the stencil as described above. In one embodiment, the squeegee blade assembly 52 includes two squeegee blades, with the viscous material, e.g., solder paste, disposed between the squeegee blades.

[0025] As discussed above, solder paste may accumulate on the squeegee blade of the squeegee blade assembly 52. ​​Unwanted dripping of solder paste from the squeegee blade may contaminate the operating workspace of the stencil printer 10 during operation. For example, when replacing a stencil, such as stencil 18, solder paste may drip from the squeegee blade onto the replacement stencil. Such contamination may result in defective printing operations on electronic boards processed through the stencil printer. Aspects of the present disclosure are directed to recovering excess solder paste from the squeegee blade of the squeegee blade assembly 52 during operation of the stencil printer 10.

[0026] 5-9, an embodiment of the printhead assembly 20 further includes a squeegee drip collection system configured to prevent undesired solder paste from dripping from the squeegee blades of the squeegee blade assembly 52 of the printhead assembly 20 onto the stencil 18 during operation of the stencil printer 10. The squeegee drip collection system is further configured to remove a full or otherwise contaminated paste shield from the printhead gantry of the stencil printer and install a new, clean paste shield.

[0027] Specifically, the squeegee drip collection system may extend and retract a collection device, such as a paste shield, under the squeegee blade to claim or collect solder paste that drips from the squeegee blade during downtime. For example, when replacing a stencil, such as stencil 18, the squeegee blade assembly 52 of the printhead 48 is raised from the stencil and the paste shield of the squeegee drip collection system is deployed to collect and hold solder paste that drips from the squeegee blade. When the stencil 18 is replaced, the paste shield of the squeegee drip collection system is retracted to allow the squeegee blade from the printhead 48 to lower onto the stencil 18. When full, as described above, the squeegee drip collection system is configured to automatically replace the full paste shield with a new, clean paste shield.

[0028] It should be understood that the squeegee drip collection system may be utilized during other operations, including changing tooling on a substrate support assembly, changing a squeegee blade from a squeegee blade assembly, to name a few.

[0029] 10, the squeegee drip collection system includes a paste shield, generally designated 60, which may be coupled to the printhead assembly 20 or printhead gantry 22. In one embodiment, the paste shield 60 includes a flat bottom wall 62, a front wall 64, a rear wall 66, and two side walls 68, 70 that create a relatively shallow receptacle or tray that receives solder paste from the squeegee blade of the squeegee blade assembly 52. ​​In another embodiment, the paste shield 60 includes only the bottom wall 62. The front wall 64 includes a first storage feature 72 and a second storage feature 74, each of which extends beyond the periphery of the front wall. In one embodiment, the storage features 72, 74 are part of a structure 76 that is secured to the paste shield 60. The purpose of the storage features 72, 74 will be explained in more detail as the description of the squeegee drip collection system proceeds. As shown, the paste shield 60 has a length that generally corresponds to or is slightly longer than the length of the squeegee blades of the squeegee blade assembly 52. ​​The length and width of the paste shield 60 can be determined based on the size and shape of the squeegee blades of the squeegee blade assembly 52.

[0030] In one embodiment, the squeegee drip collection system further comprises at least one extension mechanism used to extend the paste shield 60 beneath the squeegee blade of the squeegee blade assembly 52 during operation. In the illustrated embodiment, two spaced apart extension mechanisms, generally indicated at 80, 82, are provided for releasably securing and laterally moving the paste shield 60 beneath the squeegee blade of the squeegee blade assembly 52. ​​Specifically, the extension mechanisms 80, 82 are configured to be received within third and fourth storage features provided within the bottom wall 62 of the paste shield or within the support structure 76, the third and fourth storage features being positioned adjacent the first and second storage features 72, 74, respectively.

[0031] 5 and 6 show extension mechanisms 80, 82 that extend the paste shield 60 to an extended position to position the paste shield under the squeegee blade of the squeegee blade assembly 52. ​​The extension mechanisms 80, 82 are configured to retract the paste shield 60 to allow the squeegee blade assembly 52 to be lowered onto the stencil 18 without interfering with the squeegee blade assembly. The structure of each extension mechanism 80, 82 and the third and fourth storage features will be described with reference to Figures 13A-13C.

[0032] 5-9, the collection system further includes a plate 42 that is mounted to the printhead gantry 22. The plate 42 includes two pairs of linear bearings 44a, 44b and 46a, 46b. As shown, the linear bearings 44a, 46a are configured to support a first tooling member, generally indicated at 86, and the linear bearings 44b, 46b are configured to support a second tooling member, generally indicated at 88, that are configured to move laterally on their respective pairs of linear bearings.

[0033] Any suitable mechanism may be employed to move the tooling members 86, 88 laterally along the linear bearings 44a, 46a and 44b, 46b, respectively. For example, in one embodiment, a ball screw drive assembly may be employed to move the tooling members 86, 88 along the linear bearings 44a, 46a and 44b, 46b, respectively. In some embodiments, the ball screw drive assembly provided to move the tooling members 86, 88 along the linear bearings 44a, 46a and 44b, 46b, respectively, may also provide power for the up and down movement of the printhead 48 in the z-axis direction. As described above, the printhead 48 of the printhead assembly 20 is configured to be lowered to engage the stencil 18 during a printing operation and raised to disengage the stencil when a printing operation is not being performed. When lowered, the printhead 48 applies pressure to the squeegee blade assembly 52 as the squeegee blade assembly sealingly engages the stencil 18.

[0034] 10 and 11, the first tooling member 86 includes a first housing 90 secured to the linear bearings 44a, 46a, the first housing configured to advance laterally along the linear bearings. The first tooling member 86 further includes a first downwardly extending pin 92 disposed within a first pneumatic cylinder 98 mounted on the first housing 90, the first pin having an end configured to be received within one of the receiving features of the paste shield 60, described in more detail below, such as the first receiving feature 72.

[0035] Similarly, the second tooling member 88 includes a second housing 94 secured to the linear bearings 44b, 46b, the second housing configured to advance laterally along the linear bearings. The second tooling member 88 further includes a second downwardly extending pin 96 disposed within a second pneumatic cylinder 100 mounted on the second housing 94, the second pin having an end configured to be within another storage feature of the paste shield 60, such as the second storage feature 74. The storage features 72, 74 of the paste shield 60 are configured to be engaged by the pins 92, 96 of the first tooling member 86 and the second tooling member 88, respectively, to engage and move the paste shield.

[0036] A first pneumatic cylinder 98 and a second pneumatic cylinder 100 are configured to drive the up and down movement of a first pin 92 in the first housing 90 and a second pin 96 in the second housing 94, respectively. The first pneumatic cylinder 98 and the second pneumatic cylinder 100 are coupled to the controller 14 and a source of air pressure to control the up and down movement of the pins 92, 96 independently of one another.

[0037] In one embodiment, referring to FIG. 7, the pins 92, 96 of the tooling members 86, 88 are received in the first and second storage features 72, 74 of the paste shield 60, respectively. The tooling members 86, 88 can be moved to a width close to the width of the first and second storage features 72, 74 of the paste shield 60. When positioned in front of the first and second storage features 72, 74 of the paste shield 60, the paste shield is moved by the extension mechanisms 80, 82 toward the tooling members 86, 88, such that the ends of the tooling members are received in the respective storage features of the paste shield, securing the paste shield to the tooling members. The tooling members 86, 88 can be positioned by moving them along the linear bearings 44a, 46a and 44b, 46b, respectively. Additionally, the pins 92, 96 of the tooling members 86, 88 can be lengthened or shortened to achieve the appropriate lift of the ends of the pins relative to the first and second storage features 72, 74. The printhead assembly 20 is configured to be moved in the y-axis direction by the printhead gantry 22 to engage and move the paste shield 60. This position is shown in Figures 8 and 9.

[0038] It should be appreciated that the pins of the tooling members 86, 88 can employ a variety of mechanisms used to engage and move the paste shield 60. In the illustrated embodiment, the pins 92, 96 of the tooling members 86, 88 have ends that are received in the first and second receiving features 72, 74, respectively, of the paste shield 60. For example, the pins 92, 96 of the tooling members 86, 88 can each include a magnet to facilitate attachment and removal of the paste shield from the tooling members for lifting and moving the paste shield 60.

[0039] 12A-12C, as described above, the tooling members 86, 88 can be configured to pick up and release the paste shield 60. Specifically, the tooling members 86, 88 are configured to toolessly engage and disengage the first and second storage features 72, 74 of the paste shield 60 to disengage the paste shield from the extension mechanisms 80, 82 and secure and remove the paste shield. As described in more detail below, the paste shield 60 can be configured with a spring-loaded locking mechanism that secures the paste shield to the extension mechanisms 80, 82.

[0040] The method of passively picking up and dropping the paste shield 60 without the need for additional axes or actuators can be accomplished by tooling members 86,88.

[0041] 12A, for the pins 92, 96 of both tooling members 86, 88, as the ends of the pins enter the recesses of their respective storage features 72 or 74, the pins move the spring loaded mechanism 110 against the bias of the spring to release the extension mechanism 80 or 82 from the paste shield 60. Thus, the arrangement is such that the extension members 80, 82 are released from the third and fourth storage features as the ends of the pins 92, 96 enter their respective third and fourth storage features. Once positioned, the pins 92, 96 of the tooling members 86, 88 are secured to the paste shield 60 to support the paste shield when the extension mechanisms 80, 82 are released from the paste shield.

[0042] 13A-13C, each extension mechanism 80, 82 includes a bracket 114 secured to the carriage 50 of the printhead gantry 22 and an extension member 116 mounted on the bracket. As shown, in one embodiment, the extension member 116 includes a cylinder 118 mounted to the bracket 114 and a rod 120 reciprocally received within the cylinder. An air supply (not shown) can be connected to the cylinder 118 to provide reciprocating movement of the rod 120 within the cylinder. The rod 120 of the extension members 80, 82 is used to extend and retract the paste shield 60 under the squeegee blade assembly 52.

[0043] Each rod 120 may be further configured to include an end that is stored within a respective third and fourth storage feature of the paste shield 60. FIG 12B shows an end of the rod 120 that is configured to be removed from the storage feature 122 of the paste shield 60. FIG 12C shows an end of the rod 120 that is configured to be captured by the storage feature 122 of the paste shield 60.

[0044] An embodiment of the present disclosure includes a method for capturing solder paste that may potentially drip from the squeegee blades of the squeegee blade assembly 52 of the printhead 48 during operation. In one embodiment, the method includes moving the paste shield 60 from a retracted position to an extended position beneath the squeegee blades of the squeegee blade assembly 52. ​​The method further includes the ability to replace the paste shield 60 using tooling members 86, 88.

[0045] In one embodiment, a method of removing the paste shield 60 from the squeegee blade assembly 52 includes positioning tooling members 86, 88 adjacent storage features 72, 74 of the paste shield, moving the paste shield 60 toward the tooling members 86, 88 with the extension mechanisms 80, 82, positioning the tooling members 86, 88 within the respective storage features 72, 74 to release the paste shield 60 from the extension mechanisms 80, 82, and supporting the paste shield 60 with the tooling members 86, 88. Although two tooling members 86, 88, two storage features 72, 74, and two extension members 80, 82 are shown and described in this disclosure, any number of tooling members, storage features, and extension members may be provided to perform the methods described in this disclosure.

[0046] The systems and associated methods disclosed in this disclosure may be performed under the control of the controller 14. In particular, the controller 14 may be configured to know when to move the paste shield and when to replace the paste shield.

[0047] In some embodiments, the existing stencil printer gantry, rails and printhead of stencil printer 10 can be configured to load and unload parts including the paste shield.

[0048] In some embodiments, the printhead assembly 20 of the stencil printer 10 may be configured to move and reciprocate the paste shield.

[0049] As used in this disclosure, "automated" or "fully automated" conversion describes replacing or replenishing parts without human intervention.

[0050] As used in this disclosure, a "partially automated" conversion describes replacing or replenishing parts with some or limited human intervention.

[0051] As used in this disclosure, "transport" or "transporting" describes the moving of parts from one location to another, either manually or using a machine.

[0052] As used in this disclosure, "install" or "installing" describes the process of placing a part in a position ready for use.

[0053] As mentioned above, the movable cart can be utilized to replace other parts within the stencil printer, for example, the stencil wiper assembly includes consumables such as paper and solvent that can be automatically replaced by the movable cart.

[0054] The concepts disclosed in this disclosure may be utilized in other types of equipment used to fabricate electronic boards, including dispensers, pick and place machines, reflow ovens, wave soldering machines, selective soldering machines, inspection stations, and cleaning stations. For example, concepts directed to recapturing material can be utilized in soldering and wave soldering machines and cleaning stations.

[0055] Having thus described several aspects of at least one embodiment, it will 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 scope of this disclosure. Accordingly, the foregoing description and drawings are by way of example only.

Claims

【Claim 1】 A stencil printer for printing an assembly material on an electronic substrate, comprising: a frame; a stencil connected to the frame, the stencil having holes formed therein; a support assembly connected to the frame, the support assembly being configured to support the electronic substrate; a print head gantry connected to the frame, the print head gantry comprising an elongated beam supported along a rail provided on the frame, the elongated beam of the print head gantry including at least one linear bearing extending in a horizontal direction; a print head assembly supported by the print head gantry such that the print head assembly is configured to traverse the stencil during a printing stroke; a squeegee drip recovery system configured to receive the assembly material from at least one squeegee blade of the print head assembly, the squeegee drip recovery system including a paste shield connected to the print head gantry, the paste shield being configured to move between a retracted position spaced from the at least one squeegee blade and an extended position positioned under the at least one squeegee blade, and further including a paste shield removal assembly configured to disconnect the paste shield from the print head gantry to remove the paste shield, the paste shield removal assembly including at least one turret member configured to move laterally on the at least one linear bearing, the at least one turret member including a pin extending downwardly, the pin having an end portion configured to be received within a receiving feature associated with the paste shield; and the paste shield includes at least one receiving feature, the at least one receiving feature being configured to be engaged by the pin of the at least one turret member to engage the paste shield and move the paste shield. The at least one tooling member includes two spaced-apart tooling members, each tooling member includes a pin, the first tooling member is configured to move laterally on a first linear bearing, and the second tooling member is configured to move laterally on a second linear bearing. Stencil printer. Claim 2 A method of removing a paste shield configured to recover assembly material from a squeegee of a print head gantry, the print head gantry including at least one linear bearing extending horizontally, the method comprising: positioning at least one tooling member adjacent to at least one receiving feature of the paste shield, the at least one tooling member being configured to move laterally on the at least one linear bearing, the at least one tooling member including a pin extending downwardly and having an end, the end being configured to be received within a receiving feature associated with the paste shield for engaging the paste shield and moving the paste shield; positioning the at least one tooling member; moving the paste shield toward the at least one tooling member by at least one extension mechanism; positioning the at least one tooling member within the at least one receiving feature of the paste shield to release the paste shield from the at least one extension mechanism; supporting the paste shield with the at least one tooling member; A method comprising. Claim 3 A stencil printer for printing an assembly material on an electronic substrate, a frame; a stencil coupled to the frame, the stencil having holes formed therein; a support assembly coupled to the frame, the support assembly being configured to support the electronic substrate; a print head gantry coupled to the frame, the print head gantry including an elongated beam supported along a rail provided on the frame, the elongated beam of the print head gantry including at least one linear bearing extending horizontally; a print head gantry; A printhead assembly supported by the printhead gantry such that the printhead assembly is configured to traverse the stencil during a printing stroke, A squeegee drip recovery system configured to receive assembly material from at least one squeegee blade of the printhead assembly, A paste shield coupled to the printhead gantry and configured to be moved between a retracted position in which the paste shield is spaced from the at least one squeegee blade and an extended position in which the paste shield is positioned under the at least one squeegee blade, A paste shield removal assembly configured to decouple and remove the paste shield from the printhead gantry, the paste shield removal assembly including at least one turret member configured to move laterally on at least one linear bearing, the at least one turret member including a pin having an end configured to be received within a receiving feature associated with the paste shield, A squeegee drip recovery system including, Comprising, The paste shield includes at least one receiving feature, the at least one receiving feature being configured to be engaged by the pin of the at least one turret member to engage and move the paste shield, A stencil printer.

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