Component Loading Verification System and Method

Abstract

A stencil printer for printing assembly material onto an electronic substrate includes a frame, a stencil coupled to the frame and having holes formed therein, a support assembly coupled to the frame and configured to support the electronic substrate, a printhead gantry coupled to the frame, and a printhead assembly supported by the printhead gantry such that the printhead assembly is configured to traverse the stencil during a printing stroke. The stencil printer further includes a verification system that determines whether an article placed in the stencil printer is properly installed in the stencil printer.

Description

[Technical field]

[0001] Related Applications This application is related to U.S. patent application Ser. No. (blank) by William A. Losiewicz, entitled "SQUEEGEE DRIP COLLECTION SYSTEM FOR STENCIL PRINTER," 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, and one or more small holes or marks (known as "fiducials") on the circuit board are used 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 an imaging 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] Components that are mounted or otherwise loaded into the stencil printer must be properly positioned before the stencil printer is operated. For example, the tooling plate that supports the electronic board during the stencil printing operation must be precisely loaded into the stencil printer so that there is no interference between the imaging system and the tooling or other components. Summary of the Invention

[0006] Disclosure Summary One aspect of the present disclosure is directed to a stencil printer for printing an assembly material onto an electronic substrate. In one embodiment, the stencil printer includes a frame, a stencil coupled to the frame and having holes formed therein, a support assembly coupled to the frame and configured to support the electronic substrate, a printhead gantry coupled to the frame, and a printhead assembly supported by the printhead gantry such that the printhead assembly is configured to traverse the stencil during a printing stroke. The stencil printer further includes a verification system that determines whether an article placed in the stencil printer is properly installed in the stencil printer.

[0007] An embodiment of the stencil printer may further include configuring a print head gantry with an elongated beam that travels along rails provided on the frame. The elongated beam of the print head gantry may include at least one linear bearing extending horizontally, and the verification system 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 configured to move between a fully extended (extended) position and a retracted position. The verification system may further include a controller configured to move the at least one tooling member over the article and determine whether the pin of the at least one tooling member is in the retracted position. The verification system may further include at least one sensor positioned on the at least one tooling member. The at least one sensor may be configured to generate a first visual signal indicative of the pin of the at least one tooling member being fully extended and a second visual signal indicative of the pin of the at least one tooling member being retracted. The at least one tooling member may include two spaced apart tooling members each with a pin. The first tooling member may be configured to move laterally on a first linear bearing and the second tooling member may be configured to move laterally on a second linear bearing. The pin of the at least one tooling member may have an end configured to be stored within a storage feature associated with the article. The article may include at least one storage feature configured to be engaged by the pin of the at least one tooling member to engage and move the article. The at least one tooling member may include two spaced apart tooling members each with a pin. The first tooling member may be configured to move laterally on a first linear bearing and the second tooling member may be 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, and the first and second tooling members are stored within the respective storage features of the article to releasably secure the article. The article may include a tooling plate having a flat bottom wall configured to mate with a tooling base of the stencil printer. The verification system may include at least one tooling member configured to move laterally on at least one linear bearing of the print head gantry and including a downwardly extending pin configured to move between a fully extended position and a retracted position, and a controller configured to move the at least one tooling member over the article and determine whether the pin of the at least one tooling member is in the retracted position. The verification system may further include at least one sensor positioned on the at least one tooling member, the at least one sensor configured to generate a first visual signal indicative of the pin of the at least one tooling member being fully extended and a second visual signal indicative of the pin of the at least one tooling member being retracted. The at least one tooling member can include two spaced apart tooling members each comprising a pin, The first tooling member can be configured to move laterally on a first linear bearing and the second tooling member can be configured to move laterally on a second linear bearing.

[0008] Another aspect of the present disclosure is directed to a method of verifying whether an article is properly installed in a stencil printer. In one embodiment, the method includes installing an article in the stencil printer and verifying whether the article is properly installed in the stencil printer.

[0009] An embodiment of the method may further include, when verifying whether the article is properly installed in the stencil printer, moving at least one tooling member laterally over the article on at least one linear bearing of the printhead gantry and determining whether the at least one tooling member engages the article. The at least one tooling member may include a downwardly extending pin configured to move between a fully extended position and a retracted position. Determining whether the at least one tooling member engages the article may include determining whether the pin of the at least one tooling member is in a retracted position. Determining whether the pin of the at least one tooling member is in a retracted position may include providing a first signal indicative of the pin of the at least one tooling member being fully extended and a second signal indicative of the pin of the at least one tooling member being retracted. The second signal may indicate that the article is not properly installed. The article may include a tooling plate having a flat bottom wall configured to mate with a tooling base of the stencil printer.

[0010] Yet another aspect of the disclosure is directed to a verification system for a stencil printer comprising an elongated beam of a printhead gantry having at least one horizontally extending linear bearing. The verification system comprises at least one tooling member configured to move laterally on the at least one linear bearing. The at least one tooling member can comprise a downwardly extending pin configured to move between a fully extended position and a retracted position. The verification system can further comprise a controller configured to move the at least one tooling member over the article and determine whether the pin of the at least one tooling member is in the retracted position. The verification system can further comprise at least one sensor positioned on the at least one tooling member. The at least one sensor can be configured to generate a first visual signal indicative of the pin of the at least one tooling member being fully extended and a second visual signal indicative of the pin of the at least one tooling member being retracted.

[0011] In another embodiment, the at least one tooling member can comprise two spaced apart tooling members each comprising a pin. The first tooling member can be configured to move laterally on a first linear bearing, and the second tooling member can be configured to move laterally on a second linear bearing. The pin of the at least one tooling member can have an end configured to be stored within a storage feature associated with the article. The article can comprise at least one storage feature configured to be engaged by the pin of the at least one tooling member to engage and move the article. The at least one tooling member can include two spaced apart tooling members each comprising a pin. The first tooling member can be configured to move laterally on a first linear bearing, and the second tooling member can be 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, and the first and second tooling members are stored within the respective storage features of the article to releasably secure the article. The article may include a tooling plate having a flat bottom wall configured to mate with a tooling base of the stencil printer. The verification system may include at least one tooling member configured to move laterally on at least one linear bearing of the print head gantry and including a downwardly extending pin configured to move between a fully extended position and a retracted position, and a controller configured to move the at least one tooling member over the article and determine whether the pin of the at least one tooling member is in the retracted position. The verification system may further include at least one sensor positioned on the at least one tooling member, the at least one sensor configured to generate a first visual signal indicative of the pin of the at least one tooling member being fully extended and a second visual signal indicative of the pin of the at least one tooling member being retracted.The at least one tooling member can include two spaced apart tooling members each comprising a pin, The first tooling member can be configured to move laterally on a first linear bearing and the second tooling member can be configured to move laterally on a second linear bearing.

[0012] 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]

[0013] [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. 2 is a perspective view of a printhead assembly having a tooling member pin according to one embodiment of the present disclosure. [Diagram 5] FIG. 2 is a top view of the printhead assembly. [Figure 6] FIG. 2 is another perspective view of the printhead assembly. [Figure 7] 11A-11C are front views of the printhead assembly showing a series of positions of the tooling members to remove and verify the position of the tooling of the stencil printer. [Figure 8] 11A-11C are front views of the printhead assembly showing a series of positions of the tooling members to remove and verify the position of the tooling of the stencil printer. [Figure 9] 11A-11C are front views of the printhead assembly showing a series of positions of the tooling members to remove and verify the position of the tooling of the stencil printer. [Figure 10]11A-11C are front views of the printhead assembly showing a series of positions of the tooling members to remove and verify the position of the tooling of the stencil printer. [Figure 11] 11A-11C are front views of the printhead assembly showing a series of positions of the tooling members to remove and verify the position of the tooling of the stencil printer. [Figure 12] FIG. 13 is a front view of verifying that the tooling is in the proper position. [Figure 13] FIG. 13 is a front view of verifying that the tooling is in an improper position. [Figure 14] FIG. 13 is a schematic diagram of the pneumatic configuration of the tooling member. [Figure 15] FIG. 2 is a schematic diagram of the electrical configuration of the tooling member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] 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.

[0015] 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" may be construed as inclusive such that any term described with "or" may refer to any one, more than one, and all of the described term. Additionally, in the event of inconsistencies in the usage of a term between this document and any document incorporated by reference into this disclosure, the usage of the term in the document incorporated by reference into this disclosure is supplementary to the usage in this document, and in the event of any inconsistencies, the usage of the term in this document shall prevail.

[0016] 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.

[0017] 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.

[0018] 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 can be lowered in the z-axis direction into contacting and sealing engagement with the stencil.

[0019] 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 circuit boards to and from a work area of ​​the stencil printer, sometimes referred to in this disclosure as a "print nest."

[0020] 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.

[0021] 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 printing operations. 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.

[0022] 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.

[0023] 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.

[0024] 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 travel underneath the stencil to remove the excess solder paste. In other embodiments, the stencil 18 may travel above the stencil wiper assembly.

[0025] 4-6, 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.

[0026] The embodiments of the stencil printer 10 are directed to systems and methods for determining whether a tooling plate or other part is loaded correctly into the stencil printer and there is no interference between subassemblies of the stencil printer, such as the imaging system 30 and the tooling or other part. Specifically, the stencil printer 10 includes a tooling member configured to extend and retract in the z-axis direction, the tooling member mounted to the print head 20 or print head gantry 22 to allow movement in the x-axis direction and the y-axis direction. By moving the tooling member in the x-axis direction, the y-axis direction, and the z-axis direction, the stencil printer 10 can be configured to detect the height of components, including the tooling plate, to determine whether these components are properly loaded or positioned in the stencil printer. The tooling member can be configured with limit sensors that detect whether the tooling member is fully extended or retracted. The tooling member can be positioned and lowered to contact a top surface of the tooling or part until the limit sensor changes state. A position counter can be employed to count when the limit sensors transition from on to off and then compared to a calibration value determined when the stencil printer 10 is initially calibrated. This determination can inform the operator of the stencil printer 10 that the tooling plate is correctly positioned and positioned at the correct height to prevent it from interfering with other components of the stencil printer 10, such as the imaging system 30. Additionally, the stencil printer 10 can be configured with a "bias" regulator to maintain the tooling members in an extended position when verification is being performed.

[0027] As described above, a plate 42 is attached 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 60, and the linear bearings 44b, 46b are configured to support a second tooling member, generally indicated at 62, which are configured to move laterally on their respective pairs of linear bearings.

[0028] Any suitable mechanism may be employed to move the tooling members 60, 62 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 60, 62 along the linear bearings 44a, 46a and 44b, 46b, respectively. In some embodiments, the ball screw drive assembly provided to move the tooling members 60, 62 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 52 sealingly engages the stencil 18 in a conventional manner.

[0029] In one embodiment, the first tooling member 60 comprises a first housing 64 secured to the linear bearings 44a, 46a, the first housing configured to advance laterally along the linear bearings. The first tooling member 60 further comprises a first downwardly extending pin 66 disposed within a first pneumatic cylinder 68, the first pin having an end configured to be received within a storage feature of an item desired to be moved by the tooling member, described in more detail below.

[0030] Similarly, the second tooling member 62 includes a second housing 70 secured to the linear bearings 44b, 46b, the second housing configured to advance laterally along the linear bearings. The second tooling member 62 further includes a second downwardly extending pin 72 disposed within a second pneumatic cylinder 74, the second pin having an end also configured to reside within the storage feature of the item. The first pneumatic cylinder 68 and the second pneumatic cylinder 74 are coupled to the controller 14 and a pneumatic source to control the up and down movement of the pins 66, 72 of the tooling members 60, 62, respectively, independently of one another.

[0031] 7-11, an embodiment of the printhead assembly 20 includes a tooling plate, generally indicated at 80, configured to be loaded onto and removed from a tooling base 82 of the stencil printer 10. The tooling plate 80 is provided to support an electronic substrate during a printing operation. As shown, the tooling base 82 may include alignment pins, each indicated at 84, that are provided to align the tooling plate 80 and ensure that the tooling plate 80 is accurately positioned on the tooling base. The tooling plate 80 includes openings positioned and configured to receive the alignment pins 84 when the tooling plate is positioned on the tooling base 82.

[0032] The tooling plate 80 is a generally rectangular structure having a flat bottom wall 86 that rests on the flat surface of the tooling base 82 of the substrate support assembly 28, a short front wall, a short back wall, and two short side walls. The openings mentioned above are formed in the bottom surface of the bottom wall 86 of the tooling plate 80. As shown, one side wall includes a first storage feature 96 that extends beyond the periphery of the side wall. Similarly, the other side wall includes a second storage feature 98 that extends beyond the periphery of the side wall. The storage features 96, 98 are configured to be engaged by the pins 66, 72 of the first and second tooling members 60, 62, respectively, to engage the tooling plate 80 and move the tooling plate 80.

[0033] 7, the ends of the pins 66, 72 of the tooling members 60, 62 are accommodated within the first and second storage features 96, 98, respectively, of the tooling plate 80. The tooling members 60, 62 can be moved to a width that approximates the width of the first and second storage features 96, 98 of the tooling plate 80. When positioned on either side of the first and second storage features 96, 98 of the tooling plate 80, the ends of the pins 66, 72 of the tooling members 60, 62 are moved completely within the storage features to engage and support the tooling plate. The tooling members 60, 62 can be positioned by moving along the linear bearings 44a, 46a and 44b, 46b, respectively, to accommodate tooling plates having various spacings of storage features. Additionally, the pins 66, 72 of the tooling members 60, 62 can be lengthened or shortened to achieve the appropriate elevation of the ends of the pins relative to the first and second storage features 96, 98. The printhead assembly 20 is configured to be moved in the y-axis direction by the printhead gantry 22 to engage the tooling plate 80 and move the tooling plate 80 to the appropriate position above the tooling base 82.

[0034] It should be appreciated that the ends of the pins 66, 72 of the tooling members 60, 62 can employ a variety of mechanisms used to engage and move the tooling plate 80. In the illustrated embodiment, the pins 66, 72 of the tooling members 60, 62 have ends that are received in a first storage feature 96 and a second storage feature 98, respectively, of the tooling plate 80. For example, the pins 66, 72 of the tooling members 60, 62 can each include a magnet to facilitate attachment and removal of the tooling plate 80 from the tooling members for lifting and moving the tooling plate.

[0035] As discussed above, the tooling members 60, 62 can be configured to pick up and release the tooling plate 80. Specifically, the tooling members 60, 62 are configured to engage and disengage the first and second storage features 96, 98 of the tooling plate 80 toolessly.

[0036] 8, tooling plate 80 is lowered into engagement and seating on tooling base 82 with tooling base alignment pins 84 (FIG. 7) received within openings in the tooling plate. As shown, tooling plate 80 rests flat on the upper surface of tooling base 82. The bottom surface of bottom wall 86 of tooling plate 80 can be configured to mate with the upper surface of tooling base 82 to provide precise positioning of the tooling plate on the tooling base.

[0037] 9, to remove the tooling members 60, 62 from the storage features 96, 98 of the tooling plate 80, the tooling members are moved outwardly relative to the tooling plate. Specifically, the first tooling member 60 shown in FIG. 9 is moved leftward along the linear bearings 44a, 46a away from the storage feature 96 of the tooling plate 80 such that the pin 66 is cleared away from the storage feature. Similarly, the second tooling member 62 shown in FIG. 9 is moved rightward along the linear bearings 44b, 46b away from the storage feature 98 of the tooling plate 80 such that the pin 72 is cleared from the storage feature.

[0038] 10, the printhead 20 is raised to move the ends of the pins 66, 72 of the tooling members 60, 62 upwardly so that the ends of the pins 66, 72 of the tooling members 60, 62 are positioned along a plane that is directly above the plane of the upper surface of the tooling plate 80. As shown, the pins 66, 72 of the tooling members 60, 62 are fully extended.

[0039] 11, the tooling members 60, 62 are moved inwardly such that the ends of the tooling member pins 66, 72 are disposed just above the upper surface of the tooling plate 80. Specifically, the first tooling member 60 shown in FIG. 11 is moved to the right along the linear bearings 44a, 46a toward the second tooling member 62. Similarly, the second tooling member 62 shown in FIG. 11 is moved to the left along the linear bearings 44b, 46b toward the first tooling member 60. As shown, the ends of the tooling members 60, 62 pins 66, 72 are disposed just above the upper surface of the tooling plate 80.

[0040] 12, a verification system for determining whether the tooling plate 80 is properly positioned on the tooling base. As shown, the verification system includes a first sensor 110 positioned on the first tooling member 60 adjacent to the first pneumatic cylinder 68. The first sensor 110 is configured to detect the position of the first tooling member 60 and generate a visual signal, e.g., a red light, when the first pin 66 of the first tooling member is fully extended, and generate another visual signal, e.g., a white light or no light, when the first pin of the first tooling member is not fully extended. The verification system further includes a second sensor 112 positioned on the second tooling member 62 adjacent to the second pneumatic cylinder 74. The second sensor 112 is configured to detect the position of the second tooling member 62 and generate a visual signal, such as a red light, when the second pin 72 of the second tooling member is fully extended and generate another visual signal, such as a white light or no light, when the second pin of the second tooling member is not fully extended. In one embodiment, the first sensor 110 and the second sensor 112 of the verification system are coupled to the controller 14 to notify an operator of the status of the sensors beyond the visual signal provided by the sensors.

[0041] In some embodiments, the verification system can generate an audible signal that one of the pins 66, 72 is not fully extended, and a notification can be generated on the display 16 of the stencil printer 10.

[0042] 12 illustrates a verification system that indicates that the tooling plate 80 is properly seated on the tooling base. As illustrated, the pins 66, 72 of the tooling members 60, 62 are in a fully extended position. Thus, a visual signal or indicator of the sensors 110, 112 indicates the fully extended position of the pins 66, 72. As a result, an operator of the stencil printer 10 will know, through visual confirmation of the first sensor 110 and the second sensor 112, or through the display 16 coupled to the controller 14, that the tooling plate 80 is properly seated on the tooling base.

[0043] 13, a verification system is shown that indicates that the tooling plate 80 is not properly seated on the tooling base 82. As shown, the first pin 66 of the first tooling member 60 is shown in a fully extended position. However, the second pin 72 of the second tooling member 62 is not fully extended. Thus, a visual signal or indicator of the first sensor 110 indicates the fully extended position of the first pin 66 of the first tooling member 60, and a visual signal of the second sensor 112 indicates the shortened position of the second pin 72 of the second tooling member 62. As a result, an operator of the stencil printer 10 will know, through visual confirmation of the first sensor 110 and the second sensor 112, or through the display 16 coupled to the controller 14, that the tooling plate 80 is not properly seated on the tooling base 82. The display 16 can prompt the operator to correct the seating of the tooling plate 80 before a catastrophic event occurs, such as the imaging system 30 interfering with the tooling plate.

[0044] 14, the pneumatic control of the first tooling member 60 and the second tooling member 62 is shown generally. As shown, a first regulator 120 is provided to control the air flow to the first tooling member 60 and the second tooling member 62 to provide downward movement and extension of the first pin 66 and the second pin 72, respectively. A second regulator 122 is provided to control the air flow to the first tooling member 60 and the second tooling member 62 to provide upward movement and retraction of the first pin 66 and the second pin 72, respectively. A solenoid valve 124 is provided between the second regulator 122 and the first tooling member 60 and the second tooling member 62 to control the air flow to the tooling members to provide retraction of the pins 66, 72. Pneumatic control of first tooling member 60 and second tooling member 62 is provided by a controller 14 which is coupled to a first regulator 120 , a second regulator 122 , and a solenoid valve 124 .

[0045] 15, there is shown a schematic of the electronic controls for the first tooling member 60 and the second tooling member 62. As shown, the controller 14 is coupled to a DC power supply 130 and an AC power supply 132 which are coupled to the first tooling member 60 and the second tooling member 62. A CAN bus module 134 is provided for controlling the extension and retraction of the pins 66, 72 of the tooling members 60, 62, respectively.

[0046] An embodiment of the present disclosure includes a method for verifying whether an article, such as a tooling plate 80, is properly seated or positioned within a stencil printer 10. In one embodiment, the method includes moving an article, such as a tooling plate 80, from a remote location to an installed location within the stencil printer 10. Once in the proper location, the method further includes verifying whether the article is properly installed within the stencil printer 10.

[0047] In one embodiment, a method for verifying whether an article is properly positioned includes fully extending the pins 66, 72 of the tooling members 60, 62, moving the pins over the article, and detecting whether the pins are retracted into their respective tooling members.

[0048] 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 an article, such as the tooling plate 80, and when to replace the article. Although the tooling plate is described in this disclosure as the subject of the verification system, the verification system may be used to determine whether other articles are properly installed in the stencil printer 10.

[0049] In some embodiments, the existing stencil printer gantry, rails and printhead of stencil printer 10 can be configured to load and unload articles including tooling plate 80 .

[0050] In some embodiments, the printhead assembly 20 of the stencil printer 10 can be configured to move and place the tooling plate 80 .

[0051] In some embodiments, each sensor, i.e., sensors 110, 112, may embody an analog position sensor configured to sense magnetic flux lines from magnets in pneumatic cylinder bores of tooling members 60, 62. The analog position sensor may interpret that linear position and convert it to an analog voltage, current, or fieldbus signal type output that may be sent to the controller 14 of the stencil printer 10 and converted to a distance measurement.

[0052] In some embodiments, each sensor, i.e., sensors 110, 112, may embody a laser height sensor configured to emit a beam of light that is directed to reflect off a target, e.g., a tooling plate, and received to interpret the height based on the deviation of the returning light to the sensor. The laser height sensor may convert this to an analog voltage, current, or fieldbus signal type output that may be sent to the controller 14 of the stencil printer 10 and converted to a distance measurement.

[0053] In some embodiments, each sensor, i.e., sensors 110, 112, may embody an ultrasonic sensor configured to emit sound waves that are detected as bouncing off a target, e.g., a tooling plate, and received to interpret a height based on the sensor's return sound. The ultrasonic sensor may convert this into an analog voltage, current, or fieldbus signal type output that may be sent to the controller 14 of the stencil printer 10 and converted into a distance measurement.

[0054] In some embodiments, each sensor, i.e., sensors 110, 112, may embody a linear analog position sensor that is an integrated slider / contact assembly. A linear analog position sensor directly detects changes in position and converts these changes into a specific resistance combined with a voltage or current sensing circuit. The output from the linear analog position sensor may be converted into an analog voltage, current, or fieldbus signal type output that may be sent to the controller 14 of the stencil printer 10 and converted into a distance measurement.

[0055] In some embodiments, each sensor, i.e., sensors 110, 112, may embody a contact probe, which may be a contact point assembly. The contact probe may be attached to a movable z-axis assembly, and when the assembly is pressed against a surface, e.g., a tooling plate, the contact probe makes or breaks contact. In combination with a voltage, current, or fieldbus type output, the change in state of the contact probe may be converted to a high or low signal that may then be sent to the controller 14 of the stencil printer 10 and, when coupled with a z-axis position counter, may be converted to a distance measurement.

[0056] In some embodiments, each sensor, i.e., sensors 110, 112, may embody a camera that is positioned to capture images across the top surface of the tooling once positioned. The images may be compared to trained images or may be compared in real time. Regions of interest may be compared to the captured images and trained images to determine if any pixels of the images have changed their state and converted to distance based on calibrated mils per pixel. Any type of camera may be used to perform this function.

[0057] As used in this disclosure, "properly positioned," "properly seated," and / or "properly installed" mean that the article is in the proper place or location within the stencil printer as determined by the controller after reviewing data associated with one or more images captured by an imaging system or camera, such known location being within a predetermined tolerance or due to a known fit between the article and a portion of the stencil printer designed to receive the article.

[0058] As used in this disclosure, "transport" or "transporting" describes the manual or automatic movement of an item from one location to another.

[0059] As used in this disclosure, "install" or "installing" describes the process of placing an item in a location ready for use.

[0060] 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.

[0061] 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

1. A stencil printer for printing an assembly material on an electronic substrate, comprising: a frame; a stencil connected to the frame; a support assembly connected to the frame and configured to support the electronic substrate; a print head gantry connected to the frame; 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 verification system for determining whether an article disposed within the stencil printer is properly installed within the stencil printer; and wherein the print head assembly includes an elongate beam that travels along a rail provided on the frame, the elongate beam of the print head gantry includes at least one linear bearing extending in a horizontal direction, and the verification system includes at least one turret member configured to move laterally on the at least one linear bearing. A stencil printer.

2. A method for verifying whether an article is properly installed within the stencil printer according to Claim 1, comprising: installing an article within the stencil printer; and verifying whether the article is properly installed within the stencil printer. A method.

3. A stencil printer for printing an assembly material on an electronic substrate, comprising: a frame; a stencil connected to the frame; a support assembly connected to the frame and configured to support the electronic substrate; a print head gantry connected to the frame; 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 verification system for determining whether an article disposed within the stencil printer is properly installed within the stencil printer; and wherein the verification system is At least one turret member configured to move laterally on at least one linear bearing of the print head gantry, the at least one turret member including a pin extending downward and configured to move between a fully extended position and a retracted position. A controller configured to move the at least one turret member over the article, the controller determining whether the pin of the at least one turret member is in the retracted position. A stencil printer including the same.

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