Dual Function Tooling Tray for Stencil Printers

Abstract

A dual-function tooling tray for a stencil printer includes a peripheral frame, a first frame member spaced from a first side of the peripheral frame, a second frame member spaced from a second side of the peripheral frame, and a third frame member extending between the first and second frame members and secured to the first and second frame members. The third frame member is configured to support at least one squeegee blade assembly. The tooling tray further includes a first support secured to the first frame member and a second support secured to the second frame member. The first and second supports are configured to support a tooling plate. The tooling tray further includes a third support secured to the first frame member and a fourth support secured to the second frame member. The third and fourth supports are configured to support a tooling plate.

Description

[Technical Field]

[0001] 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 particularly to systems and methods for replacing items in stencil printers with dual-function tooling trays. [Background technology]

[0002] 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 will 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 printer's stencil or screen before printing the solder paste onto the circuit board. In some systems, an optical alignment system embodying an imaging or vision system is used to align the circuit board with the stencil.

[0003] 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 (i.e., 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 mixes and shears the solder paste to achieve the 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, and the majority of the material remains on the circuit board due to the adhesion between the circuit board and the solder paste. The material remaining on the surface of the stencil is removed in a cleaning process before additional circuit boards are printed.

[0004] Another process in printing circuit boards involves inspecting the circuit board after solder paste has been deposited on the surface of the circuit board. Inspecting the circuit board is important to determine whether a clean electrical connection can be made. Too much solder paste can cause a short circuit, while too little solder paste in the right location can prevent electrical contact. Typically, imaging inspection systems are also utilized to provide two-dimensional or three-dimensional inspection of the solder paste on the circuit board.

[0005] Modern stencil printers require manual intervention to perform routine operations. For example, during changeover, an operator must perform many manual tasks, such as changing stencils, replacing solder paste cartridges, replacing squeegee blades, and replacing support tooling. Each of these tasks requires the operator to perform the task manually. For example, in most stencil printers, the operator must unlock the stencil, remove the stencil, properly insert the replacement stencil, and lock the replacement stencil in place. Changeover operations can take as long as 30 minutes, during which time the stencil printer is not operational, potentially resulting in an idle PCB fabrication line. Summary of the Invention

[0006] One aspect of the present disclosure relates to a dual-function tooling tray for a stencil printer. In one embodiment, the tooling tray includes a peripheral frame having four sides, a first frame member spaced apart from a first side of the peripheral frame, a second frame member spaced apart from a second side of the peripheral frame, the first and second sides of the peripheral frame being parallel to each other, and a third frame member extending between the first and second frame members and secured to the first and second frame members. The third frame member is configured to support at least one squeegee blade assembly. The tooling tray further includes a first support secured to the first frame member and a second support secured to the second frame member. The first support and the second support are configured to collectively support a tooling plate. The tooling tray further includes a third support secured to the first frame member and a fourth support secured to the second frame member, the third support and the fourth support configured to collectively support a tooling plate.

[0007] Embodiments of the tooling tray may further include positioning the first support and the second support adjacent a third side of the perimeter frame and positioning the third support and the fourth support adjacent a fourth side of the perimeter frame. The first support and the second support may be spaced apart from each other by a predetermined distance sufficient to support a tooling plate. The third support and the fourth support may be spaced apart from each other by a predetermined distance sufficient to support a tooling plate. The tooling tray may further include a first support member connected at one end to the first side of the perimeter frame and at an opposite end to the first frame member. The tooling tray may further include a second support member connected at one end to the second side of the perimeter frame and at an opposite end to the second frame member. The first support, the second support, the third support, and the fourth support each include a feature configured to engage a mating feature associated with (attached to) the tooling plate to support the tooling plate. The feature may be a pin, and the mating feature may be an opening sized to receive the pin. At least one of the first support and the second support and at least one of the third support and the fourth support may each include a fiducial configured to be detected by an imaging system. The third frame member may be perpendicular to the first frame member and the second frame member. The third frame member may include at least one squeegee blade assembly support structure. The third frame member may further include a drip tray. The drip tray may be secured to a bottom surface of the third frame member. The perimeter frame may be configured to be engaged by a gripper associated with a print head of a stencil printer.

[0008] Another aspect of the present disclosure relates to a method for replacing items in a stencil printer. In one embodiment, the method includes providing a tooling tray including a new tooling support and a new squeegee blade assembly support, and a used tooling support and a used squeegee blade assembly support, the tooling tray including a new tooling plate on the new tooling support and a new squeegee blade assembly on the new squeegee blade assembly support; removing (dismounting, removing) the used squeegee blade from a print head of the stencil printer; and removing the used squeegee blade assembly from the tooling tray. positioning a used squeegee blade assembly on a support portion; removing the used tooling plate from the support assembly of the stencil printer; positioning the used tooling plate on the used tooling support portion of the tooling tray; removing a new squeegee blade assembly from the tooling tray; installing the new squeegee blade assembly on a print head of the stencil printer; removing the new tooling plate from the tooling tray; and installing the new tooling plate on the support assembly of the stencil printer.

[0009] Embodiments of the method may further include transferring the tooling tray to the stencil printer and moving the tooling tray within the stencil printer. Moving the tooling tray may be accomplished by a gripper mechanism associated with a printhead of the stencil printer. Transferring the tooling tray to the stencil printer may include moving the tooling tray by a movable cart employed to transfer and remove the stencils and tooling tray from the stencil printer. The method may further include verifying the position of the tooling tray. Verifying the position of the tooling tray may include capturing an image of the tooling tray together with a fiducial provided on the tooling tray.

[0010] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in various figures is represented by a like reference numeral. For clarity, not every component may be labeled in every drawing. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a front perspective view of the stencil printer. [Figure 2] FIG. 2 is a front view of the stencil printer. [Figure 3] FIG. 3 is a top view, with portions removed, of the stencil printer shown in FIG. 2. [Figure 4A] FIG. 1 is a perspective view of a dual function tooling tray according to an embodiment of the present disclosure. [Figure 4B] FIG. 4B is a top view of the tooling tray shown in FIG. 4A, including a detail of a portion of the tooling tray showing the fiducials. [Figure 5A] FIG. 1 is a perspective view of a tooling tray showing a first (new) tooling and a first (new) squeegee blade assembly supported by the tooling tray. [Figure 5B] FIG. 5B is a top view of the tooling tray shown in FIG. 5A. [Figure 6A] FIG. 1 is a perspective view of a tooling tray showing a first (new) tooling, a first (new) squeegee blade assembly, and a second (used) squeegee blade assembly supported by the tooling tray. [Figure 6B] FIG. 6B is a top view of the tooling tray shown in FIG. 6A. [Figure 7A] FIG. 1 is a perspective view of a tooling tray showing a first (new) tooling, a first (new) squeegee blade assembly, a second (used) squeegee blade assembly, and a second (used) tooling supported by the tooling tray. [Figure 7B] FIG. 7B is a top view of the tooling tray shown in FIG. 7A. [Figure 8A] FIG. 1 is a perspective view of a portion of a tooling tray and a gripper shown in spaced apart relationship relative to the tooling tray. [Figure 8B] 8B is a perspective view of a portion of the tooling tray shown in FIG. 8A and a gripper shown engaged with the tooling tray. [Figure 9A] FIG. 1 is a perspective view of a tooling tray showing a first (new) tooling, a second (used) squeegee blade assembly, and a second (used) tooling supported by the tooling tray. [Figure 9B] FIG. 9B is a top view of the tooling tray shown in FIG. 9A. [Figure 9C] 9A and 9B, showing a first (new) tooling, a second (used) squeegee blade assembly, a second (used) tooling, and a frame member of the tooling tray manipulated by the gripper, all supported by the tooling tray. [Figure 9D] FIG. 9D is a top view of the tooling tray shown in FIG. 9C. [Figure 10A]FIG. 10 is a perspective view of the tooling tray showing a second (used) squeegee blade assembly and a second (used) tooling supported by the tooling tray. [Figure 10B] FIG. 10B is a top view of the tooling tray shown in FIG. 10A. [Figure 11A] FIG. 1 is a perspective view of the modified tooling. [Figure 11B] FIG. 11B is a top view of the modified tooling shown in FIG. 11A. [Figure 12A] FIG. 1 is an enlarged perspective view of a gripper according to an embodiment of the present disclosure. [Figure 12B] FIG. 12B is an enlarged side elevational view of the gripper shown in FIG. 12A. [Figure 13A] FIG. 1 is an enlarged perspective view of a portion of a printhead assembly of a stencil printer showing the gripper. [Figure 13B] FIG. 13B is a rear elevation view of a portion of the printhead assembly shown in FIG. 13A. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present disclosure relates generally to material dispensing machines (referred to herein 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) onto substrates (e.g., referred to herein as "electronic substrates," "circuit boards," "boards," "PCBs," "PCB substrates," "substrates," or "PCB boards") or to perform other operations such as inspection, rework, or placement of electronic components onto substrates. Specifically, embodiments of the present disclosure are described below with reference to stencil printers used to fabricate printed circuit boards.

[0013] By way of example only and not limitation, 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 this disclosure may be used in other embodiments and may be practiced or carried out in various ways. Furthermore, the phraseology and terminology used herein are for purposes of description and should not be considered limiting. Any reference to system and method examples, embodiments, components, elements, or operations referred to in the singular herein can also encompass embodiments that include the plural, and any reference to any embodiment, component, element, or operation referred to in the plural herein can also encompass embodiments that include only the singular. References in the singular or plural are not intended to limit the systems or methods, their components, operations, or elements disclosed herein. The use of the terms "including," "comprising," "having," "containing," "with," and variations thereof herein is meant to encompass the items listed thereafter, as well as equivalents thereof and additional items. References to "or / or" may be construed as inclusive such that any term described with "or / or" may refer to any of one, more than one, and all of the described terms. Additionally, in the event of an inconsistency in the usage of a term between this application document and a document incorporated by reference, the usage of the term in the document incorporated by reference is supplementary to the usage in this application document, and in the event of an inconsistency resulting in a conflict, the usage of the term in the application document shall control.

[0014] For illustrative purposes, the following embodiments of the present disclosure will be described with reference to a stencil printer used to print assembly materials, such as solder paste, onto circuit boards. However, those skilled in the art will appreciate that the present disclosure is not limited to stencil printers that print solder paste onto circuit boards, but can also be used in other applications requiring the dispensing of other adhesive assembly materials, such as glues and encapsulants. For example, the device can be used to print epoxies used as underfill for chip-scale packages. Furthermore, the stencil printers of the present disclosure are not limited to those that print assembly materials onto circuit boards, but also include those used to print other materials onto various substrates, such as semiconductor wafers. Additionally, the terms screen and stencil are used interchangeably herein to describe devices within the printer that define the pattern printed on the substrate. In certain embodiments, the stencil printer may include a Momentum™ or Edison™ series stencil printer platform offered by ITW Electronic Assembly Equipment of Hopkinton, Massachusetts. An exemplary stencil printer is generally indicated at 5 in FIG. 1 . In this embodiment, the stencil printer 5 is a Momentum™ series stencil printer platform offered by ITW Electronic Assembly Equipment of Hopkinton, Massachusetts.

[0015] 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 stencil printer's components, 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 described in more detail below.

[0016] As shown in FIG. 2 and described below, the stencil and printhead assembly can be coupled or otherwise connected to frame 12, as appropriate. In one embodiment, printhead assembly 20 can be mounted on printhead assembly gantry 22, which can be mounted on frame 12. Printhead assembly gantry 22 allows printhead assembly 20 to move in the y-axis direction under the control of controller 14 and to engage and apply pressure to the stencil 18. In certain embodiments, printhead assembly 20 can rest above stencil 18 and can be lowered in the z-axis direction to contact and form a seal with the stencil.

[0017] Stencil printer 10 may also have a conveyor system having rails (not shown) for transporting printed circuit boards (sometimes referred to herein as "printed wiring boards," "boards," or "electronic boards") to a printing position within the stencil printer. The rails may be referred to herein 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 herein as a "print nest."

[0018] 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 printing operations. In certain embodiments, the substrate support assembly 28 can further include a specific substrate support system, such as a rigid support, multiple pins, or flexible tooling, that is positioned below the circuit board when it is in the printing position. The substrate support system can be used in part to support an interior region of the circuit board to prevent bending or warping of the circuit board during printing operations.

[0019] In one embodiment, the printhead assembly 20 can be configured to receive solder paste from a supply source, such as a dispenser, e.g., a solder paste cartridge, that provides the solder paste to the printhead assembly during printing operations. Instead of cartridges, other methods of supplying solder paste can be utilized. For example, the solder paste can be manually deposited between 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 for fabricating circuit boards.

[0020] In one configuration, the stencil printer 10 operates as follows: A circuit board 29 is loaded into the stencil printer 10 using conveyor rails. The support assembly 28 raises and secures the circuit board 29 in the printing position. The printhead assembly 20 is then lowered in the z-axis direction until the printhead assembly blade contacts the stencil 18 with the desired pressure. The printhead assembly 20 is then moved in the y-axis direction across the stencil 18 by the printhead assembly 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 from the stencil, and the circuit board 29 is lowered back onto the conveyor rails. The circuit board 29 is then released and transported from the stencil printer 10, allowing a second circuit board to 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.

[0021] An imaging system 30 can be provided for the purposes 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 can 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 can be coupled to the frame 12 and have a beam extending between the side rails of the frame 12, providing back and forth movement of the imaging system 30 above the circuit board 29 in the y-axis direction. The imaging gantry 32 can further include a carriage device that houses the imaging system 30 and is configured to 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 imaging system 30 is configured to be positioned anywhere below the stencil 18 and above the circuit board 29 to capture images of predetermined areas of the circuit board or stencil, respectively.

[0022] 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.

[0023] As mentioned above, stencil printers have traditionally required manual intervention to replace and / or replenish certain parts. For example, a typical stencil requires replacement after a certain period of time, e.g., four hours. Stencils also require replacement for separate production runs. Additionally, solder paste cartridges, which supply temperature-controlled solder paste to stencil printers, require replacement over time, e.g., within four hours. Separate production runs may require different types of solder paste material. Another item requiring periodic replacement is the squeegee blade, which wears out with use. And finally, tooling used to support the substrate at the print station is replaced when changing from one production run to another.

[0024] In one embodiment, a method for replacing stencils and / or items located on a tooling tray can include providing clean stencils and / or items on a movable cart when a request for new stencils and / or items on the tooling tray is made for a new production run or due to wear on the existing stencils and / or items. In the production line, "dirty" or used stencils and / or items are removed from the stencil printer, and "clean" or new stencils and / or items are inserted from the movable cart into the stencil printer and secured for use. The dirty stencils and / or items are transported to a cleaning station where the stencils and / or items are cleaned and prepared for reuse. Once cleaned, the stencils and / or items can be transported back to the stencil printer or storage room, where the stencils and / or items can be reused in the same or a different production run.

[0025] A specially designed tooling tray may be provided to accommodate the transport of new and used squeegee blade assemblies and tooling within the stencil printer. Referring to Figures 4A and 4B, in one embodiment, the tooling tray is generally designated 40. As shown, the tooling tray 40 includes a square-shaped peripheral frame generally designated 42 having four sides: a first side 44, a second side 46 parallel to the first side, a third side 48 connected to the ends of the first and second sides, and a fourth side 50 connected to the opposite ends of the first and second sides. In one embodiment, the tooling tray 40 is the same size and shape as the stencil 18 of the stencil printer 10. The tooling tray 40 further includes a first frame member 52 spaced apart from the first side 44 of the perimeter frame 42 and extending between a third side 48 and a fourth side 50 of the perimeter frame, and a second frame member 54 spaced apart from the second side 46 of the perimeter frame and extending between the third side 48 and the fourth side 50 of the perimeter frame. As shown, the first side 44 of the perimeter frame 42, the first frame member 52, the second frame member 54, and the second side 46 of the perimeter frame are parallel to one another.

[0026] Tooling tray 40 further includes a third frame member 56 extending between and secured to first and second frame members 52, 54. In one embodiment, third frame member 56 includes two spaced apart rails 56a, 56b, each configured to support a squeegee blade assembly. Specifically, first rail 56a of third frame member 56 includes a squeegee blade assembly support structure 58 configured to support a squeegee blade assembly, preferably a new squeegee blade assembly. Second rail 56b of third frame member 56, spaced from first rail 56a, includes a squeegee blade assembly support structure 62 configured to support a squeegee blade assembly, preferably a used squeegee blade assembly.

[0027] As shown, the third frame member 56 is perpendicular to the first frame member 52 and the second frame member 54. Additionally, the third frame member 56 includes a drip tray 64 for collecting solder paste that may drip from a used squeegee blade assembly. As shown, the drip tray 64 extends between the first rail 56a and the second rail 56b of the third frame member 56. It is known that a used squeegee blade may contain excess solder paste that has been expelled onto the squeegee blade assembly, and if the excess solder paste drips from the squeegee blade assembly, it may drip onto working or operating members of the stencil printer 10 or onto a printed circuit board supported by the stencil printer, such as circuit board 29. This is undesirable. In one embodiment, the drip tray 64 is secured to the bottom surface of the third frame member 56 below the squeegee blade assembly support structures 58, 62.

[0028] The tooling tray 40 further includes a first support 66 secured to the first frame member 52 and a second support 68 secured to the second frame member 54 adjacent the third side 48 of the perimeter frame 42. The first support 66 and the second support 68 are configured to together support tooling. Specifically, the first support 66 and the second support 68 both extend inward relative to their respective frame members 52, 54. In the illustrated embodiment, the first support 66 and the second support 68 are positioned adjacent the third side 48 of the perimeter frame 42. Depending on the size of the tooling, the first support 66 and the second support 68 are spaced apart from each other by a predetermined distance sufficient to support the tooling. In the illustrated embodiment, the first support 66 and the second support 68 are configured to support new tooling.

[0029] The first support 66 includes a support tab 70 extending in a direction toward the second support 68. The support tab 70 includes a feature extending upward (along the z-axis) from the support tab. This feature is configured to engage a mating feature on one side of the tooling, e.g., new tooling, to support the tooling. In one embodiment, this feature embodies a pin 72, and the mating feature embodies an opening formed in the bottom surface of the support tab on one side of the tooling. The structure of the tooling is shown and described in more detail with reference to FIGS. 11A and 11B. The first support 66 further includes a smaller support tab 74 spaced from the support tab 70 and extending in a direction toward the second support 68.

[0030] Similarly, the second support 68 includes a support tab 76 extending toward the first support 66. The support tab 76 includes a feature extending upward (along the z-axis) from the support tab. This feature is configured to engage with a mating feature on the opposite side of the tooling to support the tooling. In one embodiment, this feature embodies a pin 78, and the mating feature embodies an opening formed in the bottom surface of the support tab on the opposite side of the tooling. The second support 68 also includes a smaller support tab 80 spaced apart from the support tab 76 and extending toward the first support 66. This configuration enables the support tab 70 and smaller support tab 74 of the first support 66 and the support tab 76 and smaller support tab 80 of the second support 68, respectively, to hold the tooling in the correct position for transfer from the tooling tray 40 to the stencil printer 10.

[0031] The tooling tray 40 further includes a third support 82 secured to the first frame member 52 and a fourth support 84 secured to the second frame member 54 adjacent the fourth side 50 of the peripheral frame 42. The third support 82 and the fourth support 84 are configured to support tooling together. Specifically, the third support 82 and the fourth support 84 both extend inward relative to their respective frame members 52, 54. In the illustrated embodiment, the third support 82 and the fourth support 84 are positioned adjacent the fourth side 50 of the peripheral frame 42. Depending on the size of the tooling, the third support 82 and the fourth support 84 are spaced apart from each other by a predetermined distance sufficient to support the tooling. In the illustrated embodiment, the third support 82 and the fourth support 84 are configured to support used tooling.

[0032] The third support 82 and the fourth support 84 are configured in a manner similar to the configurations of the first support 66 and the second support 68, respectively. The third support 82 includes a support tab 86 extending toward the fourth support 84. The support tab 86 includes a feature extending upward (along the z-axis) from the support tab. This feature is configured to engage with a mating feature on one side of tooling, e.g., used tooling, to support the tooling. In one embodiment, this feature embodies a pin 88, and the mating feature embodies an opening formed in the bottom surface of the support tab on one side of the tooling. The third support 82 also includes a smaller support tab 90 spaced from the support tab 86 and extending toward the fourth support 84. Similarly, the fourth support 84 includes a support tab 92 extending toward the third support 82. The support tab 92 includes a feature extending upward (along the z-axis) from the support tab. This feature is configured to engage with a mating feature on the opposite side of the tooling to support the tooling. In one embodiment, this feature embodies a pin 94, and the mating feature embodies an opening formed in the bottom surface of the support tab on the opposite side of the tooling. The fourth support 84 also includes a smaller support tab 96 spaced from the support tab 92 and extending in a direction toward the third support 82. This configuration enables the support tab 86 and smaller support tab 90 of the third support 82 and the support tab 92 and smaller support tab 96 of the fourth support 84, respectively, to hold the tooling in the correct position for transfer from the stencil printer 10 to the tooling tray 40.

[0033] 4B , in some embodiments, the first support 66 of the tooling tray 40 includes a fiducial 100 configured to be detected by a vision system, such as the imaging system 30 of the stencil printer 10. The fiducial 100 may be provided on the bottom surface of the support tab 70 of the first support 66, directly below the feature or pin 72. Similarly, the second support 68 may include an optional fiducial configured to be detected by the imaging system. This fiducial may be provided on the bottom surface of the support tab 76 of the second support 68, directly below the feature or pin 78. Providing two fiducials allows for more accurate positioning of new tooling on the first support 66 and the second support 68 before removal from the tooling tray.

[0034] Similarly, in some embodiments, the third support 82 includes a fiducial similar to fiducial 100 configured to be detected by an imaging system. This fiducial may be provided on the bottom surface of the support tab 86 of the third support 82, directly below the feature or pin 88. Similarly, the fourth support 84 may include an optional fiducial configured to be detected by an imaging system. This fiducial may be provided on the bottom surface of the support tab 92 of the fourth support 84, directly below the feature or pin 94. As with the first support 66 and the second support 68, the provision of two fiducials allows for more accurate positioning of used tooling on the third support 82 and the fourth support 84 when positioned on a tooling tray.

[0035] To help stabilize the tooling tray 40, the tooling tray includes a first support member 102 connected at one end to the first side 44 of the surrounding frame 42 and at an opposite end to the first frame member 52, and a second support member 104 connected at one end to the second side 46 of the surrounding frame 42 and at an opposite end to the second frame member 54. As shown, each of the first support member 102 and the second support member 104 is positioned intermediate the respective frame members 52, 54. The support members 102, 104 help stabilize the first frame member 52 and the second frame member 54 relative to the surrounding frame 42.

[0036] 5A and 5B, tooling tray 40 is shown supporting new tooling 110 and a new squeegee blade assembly including a front squeegee blade subassembly 120a and a rear squeegee blade subassembly 120b. Front squeegee blade subassembly 120a and rear squeegee blade subassembly 120b may collectively be referred to as squeegee blade subassemblies 120. As shown, new tooling 110 is supported by first support 66 and second support 68, front squeegee blade subassembly 120a is supported by squeegee blade assembly support structure 58 on first rail 56a of third frame member 56, and rear squeegee blade subassembly 120b is supported by squeegee blade assembly support structure 62 on second rail 56b of the third frame member. In one embodiment, when manually transferring the tooling tray 40 to the stencil printer, the tooling tray is pushed into the stencil printer a predetermined distance, for example, 70 millimeters (mm), from the fully inserted position. In another embodiment, the tooling tray 40 is pushed to a known position and then moved to the 70 mm position using a gripper mechanism associated with the stencil printer, as shown with reference to Figures 8A, 8B, 12A, 12B, 13A, and 13B. In another embodiment, when transferring the tooling tray 40 to the stencil printer using an automated delivery device, for example, a mobile cart, the tooling tray is retracted from the sleeve of the automated delivery device into the stencil printer to a position 70 mm from the fully inserted position.

[0037] 6A and 6B, the tooling tray 40 is shown supporting a used squeegee blade assembly, including a front squeegee blade subassembly 130a and a rear squeegee blade subassembly 130b, supported by the squeegee blade assembly support structure 58 on the first rail 56a and the squeegee blade assembly support structure 62 on the second rail 56b of the third frame member 56, respectively, in addition to the new tooling 110 and new squeegee blade assembly 120 shown in FIGS. 5A and 5B. The front squeegee blade subassembly 130a and the rear squeegee blade subassembly 130b may collectively be referred to as squeegee blade subassemblies 130. As shown, a drip tray 64 prevents unwanted solder paste from dripping into the stencil printer's interior compartment. In one embodiment, a gripper mechanism may be used to position and align the tooling tray 40 prior to receiving the used squeegee blade assembly 130.

[0038] 7A and 7B, tooling tray 40 is shown supporting used tooling 140 supported by third support portion 82 and fourth support portion 84, in addition to new tooling 110, new squeegee blade assembly 120, and used squeegee blade assembly 130 shown in Figures 6A and 6B. Tooling tray 40 is fully loaded with new tooling 110, used tooling 140, and new squeegee blade assembly 120 and used squeegee blade assembly 130.

[0039] 8A, 8B and 12A, 12B, 13A, and 13B, in one embodiment, a gripper mechanism, generally designated 150, includes a pair of spaced apart gripper arms 152, 154 designed to engage and move the tooling tray 40 (and stencil). As shown, each gripper arm 152, 154 includes a downwardly extending toe portion 156 and a downwardly extending middle portion 158, which together define a recess 160 sized to receive a detent portion 162 of the tooling tray 40 in the manner shown in FIGS. 8A and 8B. Specifically, the gripper arms 152 of the gripper mechanism 150 are spaced apart from the tooling tray 40 with the recess 160 positioned above the tooling tray's detent portion 162. The gripper arms 152 of the gripper mechanism 152 engage the peripheral frame 42 of the tooling tray 40, with detent portions 162 of the tooling tray received in recesses 160 in the gripper arms. Each gripper arm 152, 154 further includes a downwardly extending heel portion 164 that is used to slide or move the tooling tray 40 (or stencil) by engaging the peripheral frame 42.

[0040] 9A and 9B, the tooling tray 40 as shown in Figures 7A and 7B is shown with a new squeegee blade assembly 120 removed from the tooling tray and installed in the printhead assembly of the stencil printer. The tooling tray 40 is positioned and aligned for removing the new squeegee blade assembly 120 and positioning the assembly in the stencil printer. With the new squeegee blade assembly 120 removed, there is space to remove and position the new tooling 110 in the stencil printer.

[0041] 9C and 9D, when additional capacity in the tooling tray 40 is desired, the frame members 56 are repositioned within the tooling tray by tooling pins, each indicated at 60, associated with the printhead and printhead gantry. This additional space creates room for new tooling 110 to be removed and placed into the stencil printer.

[0042] 10A and 10B, the tooling tray 40 as shown in FIGS. 9A and 9B is now shown with a new tooling 110 removed from the tooling tray and installed on the substrate support of the stencil printer. The tooling tray 40 is ready to be completely removed from the stencil printer. A gripper mechanism 150 is employed to move the tooling tray 40 to a desired position where it can be removed from the stencil printer manually or by an automated delivery device.

[0043] 11A and 11B, an exemplary tooling is generally designated 170. As shown, tooling 170 includes a rectangular tooling plate 172 and two outwardly extending support tabs 174, 176 provided on opposite ends of the tooling plate. Each support tab 174 includes a respective opening 178, 180, as described above. Each opening is sized to receive a respective pin, e.g., pins 72, 78 of first support 66 and second support 68, respectively, from the tooling tray.

[0044] 12A, 12B, 13A, and 13B, gripper arms 152, 154 of gripper mechanism 150 are configured to allow new tooling 110 to be picked up and placed, for example, by printhead assembly 20, along with the squeegee blade assembly, while being pulled therethrough.

[0045] An exemplary sequence for changing items in a stencil printer is described below. A specific sequence of item removal and replacement is preferred to efficiently utilize the stencil printer's capabilities for automated replacement of stencils, squeegee blades, and work holder tooling. The sequence order has been developed within and around the physical constraints of the stencil printer. It should be understood that the sequence for changing items in a stencil printer disclosed herein can be adapted to any custom needs of a stencil printer or mobile cart.

[0046] The printhead and printhead gantry are used to transport and precisely position the tooling tray. The tooling tray is configured to hold the squeegee blade assembly and tooling used in the stencil printer. When the printhead and printhead gantry position the tooling tray in the stencil printer using printer imaging registration, the squeegee blade assembly and tooling may be transferred to or from the tooling tray using the printer printhead gantry. In one embodiment, an imaging system, e.g., imaging system 30, may be used to take an image of the tooling tray and determine the location of the tooling tray by using printer imaging registration software associated with a controller, e.g., controller 14.

[0047] A complete stencil printer replaceable item change requires removing the stencil and removing the squeegee blade assembly and tooling from the stencil printer, followed by removing the new squeegee blade assembly and tooling and inserting the new stencil into the printer. In one embodiment, the sequence for changing items in a stencil printer, a method that defines the order of the sequence for an automated printer tooling change, is as follows: The existing stencil is removed from the stencil printer.

[0048] A tooling tray is inserted into the stencil printer using the printhead and printhead gantry. The tooling tray includes new tooling and a new squeegee blade assembly. The tooling tray may be delivered to the stencil printer by an operator or by a movable cart. The position of the tooling tray is verified by using imaging alignment verification software associated with the controller. As described above, an imaging system may be employed to take an image of the tooling tray and send the image to the controller for verification. Additionally, the imaging system may be used to position the tooling tray so that it is precisely aligned with devices on the printhead, such as tooling pins associated with the printhead.

[0049] After determining the location of the tooling tray, the squeegee blade assembly is removed from the printhead of the stencil printer and placed into the tooling tray. The tooling is then removed from the stencil printer. Specifically, by using tooling pins associated with the printhead and printhead gantry, the tooling is picked up and placed into the tooling tray. Once the squeegee blade assembly and tooling are placed in the tooling tray, the process of loading a new squeegee blade assembly and new tooling may begin.

[0050] As described above, the tooling tray contains a new squeegee blade assembly and new tooling intended to replace the used squeegee blade assembly and used tooling previously removed from the stencil printer. The new squeegee blade assembly is then picked up and installed on the printhead. The new tooling is then placed on the stencil printer's work holder table, e.g., support assembly 28, by using tooling pins associated with the stencil printer's printhead and printhead gantry. After installing the new squeegee blade assembly and new tooling, the tooling tray is removed from the stencil printer.

[0051] A new stencil is inserted into the stencil printer, at which point the sequence for replacing items in the stencil printer is complete.

[0052] The movable cart may be configured to deliver and remove the stencil and tooling tray from the stencil printer. For example, in one embodiment, the stencil printer may be configured to move the stencil and tooling tray to an appropriate position where the movable cart is configured to complete the removal. The stencil and / or tooling tray may be moved and positioned within the stencil printer by tooling pins associated with the printhead and printhead gantry. Specifically, the tooling pins may be used to engage the stencil and / or tooling tray and move the stencil and / or tooling tray laterally within the stencil printer.

[0053] As used herein, "automated" or "fully automated" changeover describes replacing or replenishing items without human intervention.

[0054] As used herein, "partially automated" changeover describes replacing or replenishing items with some or limited human intervention.

[0055] As used herein, "transport" or "transporting" describes the manual or mechanical movement of an item from one location to another.

[0056] As used herein, "install" or "installing" describes the process of placing an item in a location ready for use.

[0057] As mentioned above, the movable cart can be utilized to change other items within the stencil printer, for example, the stencil wiper assembly includes consumables such as paper and solvent that can be automatically changed by the movable cart.

[0058] The concepts disclosed herein 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, and inspection stations. For example, concepts related to replacing paste cartridges may be utilized in dispensers used to dispense viscous materials. In another example, concepts related to replacing tooling may be utilized in dispensers and pick-and-place machines used to attach electronic components to electronic boards. In another example, concepts related to replacing items may be utilized to replace solder in wave soldering machines and selective soldering machines, and to clean products in cleaning stations.

[0059] 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. 1. A dual function tooling tray for a stencil printer, comprising: a perimeter frame having four sides; a first frame member spaced from a first side of the perimeter frame; a second frame member spaced from a second side of the perimeter frame, the first side and the second side of the perimeter frame being parallel to one another; a third frame member extending between and secured to the first and second frame members, the third frame member configured to support at least one squeegee blade assembly; and a first support secured to the first frame member and a second support secured to the second frame member, the first support and second support being configured to collectively support a tooling plate; a third support secured to the first frame member and a fourth support secured to the second frame member, the third support and the fourth support being configured to collectively support a tooling plate; A tooling tray.

2. 2. The tooling tray of claim 1, wherein the first support and the second support are positioned adjacent a third side of the perimeter frame, and the third support and the fourth support are positioned adjacent a fourth side of the perimeter frame.

3. 3. The tooling tray of claim 2, wherein the first support portion and the second support portion are spaced apart from each other by a predetermined distance sufficient to support the tooling plate.

4. 4. The tooling tray of claim 3, wherein the third support and the fourth support are spaced apart from each other by a predetermined distance sufficient to support the tooling plate.

5. 10. The tooling tray of claim 1, further comprising a first support member connected at one end to the first side of the perimeter frame and at an opposite end to the first frame member.

6. 6. The tooling tray of claim 5, further comprising a second support member, said second support member connected at one end to said second side of said perimeter frame and at an opposite end to said second frame member.

7. 2. The tooling tray of claim 1, wherein the first support, the second support, the third support, and the fourth support each include a feature configured to engage a mating feature associated with the tooling plate to support the tooling plate.

8. The tooling tray of claim 7 , wherein the feature is a pin and the mating feature is an opening sized to receive the pin.

9. 8. The tooling tray of claim 7, wherein at least one of the first support and the second support and at least one of the third support and the fourth support each include a fiducial configured to be detected by an imaging system.

10. The tooling tray of claim 1 , wherein the third frame member is perpendicular to the first frame member and the second frame member.

11. The tooling tray of claim 1 , wherein the third frame member includes at least one squeegee blade assembly support structure.

12. The tooling tray of claim 11 , wherein the third frame member further includes a drip tray.

13. 13. The tooling tray of claim 12, wherein the drip tray is secured to a bottom surface of the third frame member.

14. The tooling tray of claim 1 , wherein the perimeter frame is configured to be engaged by a gripper associated with a printhead of a stencil printer.

15. 1. A method for replacing an item in a stencil printer, comprising: providing a tooling tray including a new tooling support and a new squeegee blade assembly support, and a used tooling support and a used squeegee blade assembly support, the tooling tray including a new tooling plate on the new tooling support and a new squeegee blade assembly on the new squeegee blade assembly support; removing a used squeegee blade from a print head of the stencil printer; positioning the used squeegee blade assembly on the used squeegee blade assembly support of the tooling tray; removing a used tooling plate from a support assembly of the stencil printer; positioning the used tooling plate on the used tooling support of the tooling tray; removing the new squeegee blade assembly from the tooling tray; installing the new squeegee blade assembly on the print head of the stencil printer; removing the new tooling plate from the tooling tray; placing the new tooling plate on the support assembly of the stencil printer; A method comprising:

16. 16. The method of claim 15, further comprising: presenting the tooling tray to the stencil printer; and moving the tooling tray within the stencil printer.

17. The method of claim 16 , wherein moving the tooling tray is accomplished by a gripper mechanism associated with the printhead of the stencil printer.

18. 17. The method of claim 16, wherein transferring the tooling tray to the stencil printer includes moving the tooling tray by a movable cart employed to transfer and remove the stencils and tooling tray from the stencil printer.

19. The method of claim 15 further comprising verifying the position of the tooling tray.

20. 20. The method of claim 19, wherein verifying the position of the tooling tray includes capturing an image of the tooling tray along with a fiducial provided on the tooling tray.

Images