BACKGROUND OF THE DISCLOSURE

1. Field of Invention

This application relates generally to stencil printers and related methods to print viscous materials, e.g., solder paste, on an electronic substrate, e.g., a printed circuit board (PCB), and more particularly to systems and methods for replacing items in a stencil printer.

2. Discussion of Related Art

In manufacturing a surface-mount printed circuit board, 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 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 or screen of the stencil printer prior to printing solder paste onto the circuit board. In some systems, an optical alignment system embodying a vision system is used to align the circuit board with the stencil.

Once the circuit board has been properly aligned with the stencil in the printer, the circuit board is raised to the stencil, solder paste is dispensed onto the stencil, and a wiper blade (or squeegee) traverses the stencil to force the solder paste through apertures in the stencil and onto the circuit board. As the squeegee is moved across the stencil, the solder paste tends to roll in front of the blade, which desirably causes mixing and shearing of the solder paste so as to attain a desired viscosity to facilitate filling of the apertures in the screen or stencil. The solder paste typically is dispensed onto the stencil from a standard cartridge. The stencil is then separated from the circuit board and the adhesion between the circuit board and the solder paste causes most of the material to stay on the circuit board. Material left on the surface of the stencil is removed in a cleaning process before additional circuit boards are printed. Another process in the printing of circuit boards involves inspection of the circuit boards after solder paste has been deposited on the surface of the circuit boards. Inspecting the circuit boards is important for determining that clean electrical connections can be made. An excess of solder paste can lead to shorts, while too little solder paste in appropriate positions can prevent electrical contact. Generally, the vision inspection system is further employed to provide a two-dimensional or a three-dimensional inspection of the solder paste on the circuit board.

Present day stencil printers require manual intervention to perform routine operations. For example, during a changeover, an operator must perform many manual tasks, such as changing a stencil, replacing a solder paste cartridge, replacing squeegee blades, and replacing support tooling. Each of these tasks require the operator to manually perform the task. For example, with most stencil printers, the operator must unlock the stencil, remove the stencil, properly insert a replacement stencil, and lock the replacement stencil in place. A changeover operation can take as long as 30 minutes, during which the stencil printer is not operating, which may result in the PCB fabrication line not operating.

SUMMARY OF THE DISCLOSURE

One aspect of the present disclosure is directed to a method for replacing items in a stencil printer. In one embodiment, the method comprises: removing a used stencil from the stencil printer; inserting an empty tooling tray into the stencil printer; removing used squeegee blades from a print head of the stencil printer; positioning the used squeegee blades in the empty tooling tray; removing used tooling from a support assembly of the stencil printer; positioning the used tooling in the empty tooling tray; removing the tooling tray having the used squeegee blades and the used tooling from the stencil printer; inserting a loaded tooling tray into the stencil printer, the loaded tooling tray having new squeegee blades and new tooling; installing the new tooling on the support assembly of the stencil printer; installing the new squeegee blades on the print head of the stencil printer; removing the loaded tooling tray from the stencil printer; and installing a new stencil in the stencil printer. Embodiments of the method further may include when inserting the empty tooling tray into the stencil printer, verifying a position of the empty tooling tray. Verifying the position of the empty tooling tray may include capturing an image of the empty tooling tray and determining a position of the empty tooling tray with vision registration verification software. Capturing an image of the empty tooling tray may be achieved by an imaging system of the stencil printer. The vision registration verification software may be associated with a controller of the stencil printer. Inserting the loaded tooling tray into the stencil printer may include capturing an image of the loaded tooling tray and determining a position of the loaded tooling tray with vision registration verification software. Capturing an image of the loaded tooling tray may be achieved by an imaging system of the stencil printer. The vision registration verification software may be associated with a controller of the stencil printer. Removing the used stencil, inserting the empty tooling tray, removing the tooling tray having the used squeegee blades and the used tooling, inserting the loaded tooling tray, removing the loaded tooling tray, and installing the new stencil may be achieved by using the tooling pins associated with the print head and a print head gantry of the stencil printer. A movable cart may be employed to present and remove stencils and tooling trays from the stencil printer. The movable cart may include an interface configured interact with a docking station associated with the stencil printer. The empty tooling tray may include a support for front and rear squeegee blades and a support for tooling. The method may be performed without the need of human intervention. The method further may include identifying an item by obtaining an image of the item and verifying whether the item is the correct item based on a predetermined identification mark.

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 numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings:

FIG. 1 is a front perspective view of a stencil printer; FIG. 2 is a front view of a stencil printer;

FIG. 3 is a top plan view of the stencil printer illustrated in FIG. 2 with portions removed;

FIG. 4 is a perspective view of a movable cart of an embodiment of the present disclosure, the movable cart being proximate to a stencil printer;

FIG. 5 is a flow chart showing a sequence of replacing items in a stencil printer;

FIG. 6 is a perspective view of an empty tooling tray;

FIG. 7 is a perspective view of a tooling tray having squeegee blades and tooling; and

FIG. 8 is a perspective view of the tooling tray having squeegee blades and tooling and an end effector used to secure the squeegee blades.

DETAILED DESCRIPTION OF THE DISCLOSURE

The present disclosure relates generally to material application machines (referred to herein as “stencil printers,” “screen printers,” “printing machines,” or “printers”) and other equipment utilized in a surface mount technology (SMT) process lines and configured to apply an assembly material (e.g., solder paste, conductive ink, or encapsulation material) onto a substrate (e.g., a printed circuit board, referred to herein as an “electronic substrate,” a “circuit board,” a “board,” a “PCB,” a “PCB substrate,” a “substrate,” or a “PCB board”) or to perform other operations, such as inspection, rework, or placement of electronic components onto a substrate. Specifically, embodiments of the present disclosure are described below with reference to stencil printers used to produce printed circuit boards.

For the purposes of illustration only, and not to limit the generality, the present disclosure will now be described in detail with reference to the accompanying figures. This 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 set forth in this disclosure are capable of other embodiments and of being practiced or carried out in various ways. Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. Any references to examples, embodiments, components, elements or acts of the systems and methods herein referred to in the singular may also embrace embodiments including a plurality, and any references in plural to any embodiment, component, element or act herein may also embrace embodiments including only a singularity. References in the singular or plural form are not intended to limit the presently disclosed systems or methods, their components, acts, or elements. The use herein of “including,” “comprising,” “having,” “containing,” “involving,” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. References to “or” may be construed as inclusive so that any terms described using “or” may indicate any of a single, more than one, and all of the described terms. In addition, in the event of inconsistent usages of terms between this document and documents incorporated herein by reference, the term usage in the incorporated reference is supplementary to that of this document; for irreconcilable inconsistencies, the term usage in this document controls.

For purposes of illustration, embodiments of the present disclosure will now be described with reference to a stencil printer used to print an assembly material, such as solder paste, onto a circuit board. One skilled in the art will appreciate, however, that embodiments of the present disclosure are not limited to stencil printers that print solder paste onto circuit boards, but rather, may be used in other applications requiring dispensing of other viscous assembly materials, such as glues and encapsulents. For example, the apparatus may be used to print epoxy for use as underfill for chip-scale packages. Further, stencil printers in accordance with embodiments of the present disclosure are not limited to those that print assembly materials on circuit boards, but rather, include those used for printing other materials on a variety of substrates, such as semiconductor wafers. Also, the terms screen and stencil may be used interchangeably herein to describe a device in a printer that defines a pattern to be printed onto a substrate. In certain embodiments, the stencil printer may include a Momentum® or an Edison™ series stencil printer platform offered by ITW Electronic Assembly Equipment of Hopkinton, Massachusetts. An exemplary stencil printer is generally designated at 5 in FIG. 1. In this embodiment, the stencil printer 5 is a Edison™ series stencil printer platform offered by ITW Electronic Assembly Equipment of Hopkinton, Massachusetts.

Referring to FIG. 2, there is generally indicated at 10 a stencil printer of an embodiment of the disclosure. As shown, the stencil printer 10 includes a frame 12 that supports components of the stencil printer. The components of the stencil printer may include, in part, a controller 14, a display 16, a stencil 18, and a print head or print head assembly, generally indicated at 20, which is configured to apply the solder paste in a manner described in greater detail below.

As shown in FIG. 2 and described below, the stencil and the print head assembly may be suitably coupled or otherwise connected to the frame 12. In one embodiment, the print head assembly 20 may be mounted on a print head assembly gantry 22, which may be mounted on the frame 12. The print head assembly gantry 22 enables the print head assembly 20 to be moved in the y-axis direction under the control of the controller 14 and to apply pressure on the print head assembly as it engages the stencil 18. In a certain embodiment, the print head assembly 20 may be placed over the stencil 18 and may be lowered in the z-axis direction into contact with the stencil to make a seal with the stencil.

The stencil printer 10 may also include a conveyor system having rails (not shown) for transporting a printed circuit board (sometimes referred to as a “printed wiring board,” “substrate,” or “electronic substrate” herein) to a print position in the stencil printer. The rails sometimes may be referred to herein as a “tractor feed mechanism,” which is configured to feed, load or otherwise deliver circuit boards to the working area of the stencil printer, which may be referred to herein as a “print nest,” and to unload circuit boards from the print nest.

Referring additionally to FIG. 3, the stencil printer 10 has a support assembly 28 to support the circuit board 29 (shown in dashed lines), which raises and secures the circuit board so that it is stable during a print operation. In certain embodiments, the substrate support assembly 28 further may include a particular substrate support system, e.g., a solid support, a plurality of pins or flexible tooling, which is positioned beneath the circuit board when the circuit board is in the print position. The substrate support system may be used, in part, to support the interior regions of the circuit board to prevent flexing or warping of the circuit board during the print operation.

In one embodiment, the print head assembly 20 may be configured to receive solder paste from a source, such as a dispenser, e.g., a solder paste cartridge, that provides solder paste to the print head assembly during the print operation. Other methods of supplying solder paste may be employed in place of the cartridge. For example, solder paste may be manually deposited between the blades or from an external source. Additionally, in a certain embodiment, the controller 14 may be configured to use a personal computer having a suitable operating system, such as a Microsoft Windows® operating system provided by Microsoft Corporation, with application specific software to control the operation of the stencil printer 10. The controller 14 may be networked with a master controller that is used to control a production line for fabricating circuit boards.

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 to a print position. The print head assembly 20 is then lowered in the z-axis direction until blades of the print head assembly contact the stencil 18 at a desired pressure. The print head assembly 20 is then moved in the y-axis direction across the stencil 18 by the print head assembly gantry 22. The print head assembly 20 deposits solder paste through apertures in the stencil 18 and onto the circuit board 29. Once the print head assembly has fully traversed the stencil 18 across the apertures, the print head 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 may be loaded into the stencil printer. To print on the second circuit board 29, the print head assembly is lowered in the z-axis direction into contact with the stencil and moved across the stencil 18 in the direction opposite to that used for the first circuit board.

An imaging system 30 may be provided for the purposes of aligning the stencil 18 with the circuit board 29 prior to printing and to inspect the circuit board after printing. In one embodiment, the imaging system 30 may be disposed between the stencil 18 and the support assembly 28 upon which a circuit board is supported. The imaging system 30 is coupled to an imaging gantry 32 to move the imaging system. In one embodiment, the imaging gantry 32 may be coupled to the frame 12, and includes a beam that extends between side rails of the frame 12 to provide back and forth movement of the imaging system 30 over the circuit board 29 in a y-axis direction. The imaging gantry 32 further may include a carriage device, which houses the imaging system 30, and is configured to move along the length of the beam in an x-axis direction. The construction of the imaging gantry 32 used to move the imaging system 30 is well known in the art of solder paste printing. The arrangement is such that the imaging system 30 may be located at any position below the stencil 18 and above the circuit board 29 to capture an image of predefined areas of the circuit board or the stencil, respectively.

After one or more applications of the solder paste to circuit boards, excess solder paste may accumulate at the bottom of the stencil 18 and a stencil wiper assembly, generally indicated at 34, and may move beneath the stencil to remove the excess solder paste. In other embodiments, the stencil 18 may be moved over the stencil wiper assembly.

As mentioned above, stencil printers have traditionally required manual intervention to perform replacement of certain parts and/or replenishment operations. For example, a typical stencil requires replacement after a certain period of time, e.g., four hours. Also, stencils need replacement for separate production runs. In addition, solder paste cartridges, which supply temperature-controlled solder paste to the stencil printer, require replacement over time, e.g., within four hours or less. A separate production run may require a different type of solder paste material. Another item requiring periodic replacement is squeegee blades, which are subject to wearing during use. And finally, tooling used to support a substrate in a print position is subject to replacement when changing from one production product to another.

In one embodiment, a method of replacing a stencil and/or items placed on tooling trays may include, when a request for a new stencil and/or item on a tooling tray is made, either for a new production run or because of wear on an existing stencil and/or item, a clean stencil and/or item is provided on a movable cart. At the production line, the “dirty” or used stencil and/or item is removed from the stencil printer and the “clean” or new stencil and/or item is inserted into the stencil printer from the movable cart and secured for use. The dirty stencil and/or item is transported to a cleaning station where the stencil and/or item is cleaned and ready for reuse. Once cleaned, the stencil and/or item may be transported back to the stencil printer or a stockroom, where the stencil and/or can be reused during the same or different production run.

Embodiments of the present di closure are directed to a delivery system that is configured to automate or partially automate a changeover process for a stencil printer and to implement one or more of the methods described herein. In one embodiment, the delivery system includes a movable cart that is configured to engage a stencil printer to supply and receive replacement and replenishment parts and materials to the stencil printer. For example, the stencil printer may include a docking station that is configured to receive the movable cart. The docking station may include an interface that enables the movable cart to communicate with the stencil printer. A single movable cart may be configured to include changeover stencils and/or replacement stencils. During a changeover, for example, the stencil printer must be reconfigured to produce different items. Thus, a new stencil may be employed within the stencil printer to produce a different product.

The changeover process described herein can be achieved by a single movable cart that is configured to replace and/or replenish each item. In other embodiments, more than one movable cart can be provided. For example, for stencil changeover, the movable cart is configured to support a predetermined number of stencils. The movable cart and/or the stencil printer can be configured to identify the stencils, store the stencils, transport the stencils to and from the stencil printer, inspect the stencils, and interface with the stencil printer. The movable cart also may be configured to remove used parts, such as stencils, from the stencil printer.

Embodiments of the present disclosure are further directed to a delivery system that is configured to automate a replenishment process for a stencil printer. In one embodiment, the delivery system includes a movable cart that is configured to engage a stencil printer to supply and receive replacement and replenishment parts and materials to the stencil printer. For example, the stencil printer may include a docking station that is configured to receive the movable cart. The docking station may include an interface that enables the movable cart to communicate with the stencil printer. A single movable call may be configured to include changeover stencils and replacement stencils.

The replenishment process described herein can be achieved by a single movable cart that is configured to replenish replenishable items. In other embodiments, more than one movable cart can be provided. For example, for stencil replenishment, the movable cart is configured to support several replacement solder paste cartridges. The movable cart and/or the stencil printer can be configured to identify the replacement solder paste cartridge, store the cartridges, transport the cartridges to and from the stencil printer, inspect the cartridges, and interface with the stencil printer.

Referring to FIG. 4, a movable cart, generally indicated at 200, of an embodiment of the present disclosure is configured to remove and replace items, such as stencils, squeegee blades, and tooling, from a stencil printer, generally indicated at 205, and deliver the items to a cleaning station, for example. When a request for a new item is required, either for a new production run or because of wear on an existing item, a clean item is transported by the movable cart 200 to the stencil printer 205. The “dirty” or used item is removed from the stencil printer 205 and the “clean” or new item is inserted into the stencil printer and secured for use. The dirty item is removed from the stencil printer 205 and a new item is replaced within the stencil printer. These functions can be performed by the movable cart 200.

As with stencil printer 10, the stencil printer 205 can be configured to include a docking station that is configured to receive the movable cart 200. The docking station may include an interface that enables the movable cart 200 to communicate with the stencil printer 205. The movable cart 205 can be configured with a mating interface, which is designed to dock within a docking station provided on the stencil printer 205. The arrangement is such that the movable cart 200 is configured to dock within a docking station of the stencil printer 205, both from a mechanic interface and an electronics communication interface. The movable cart 200 can be configured with a unique mechanical interface that mates with unique mechanical interfaces of the stencil printer 205. The unique mechanical interfaces can include geometric features. The movable cart 200 can be configured with pins that are capable of being received within guides associated with the stencil printer 205 to register the movable call with the stencil printer to fully dock the movable cart. Other types of guides can be used, such as electric al/magnetic guides, vision guides, sensors, latches, etc.

Referring to FIG. 5, a sequence of replacing items within a stencil printer, such as stencil printer 205, is shown and described below. To efficiently utilize the capabilities of the stencil printer for the automated exchange of the stencil, the squeegee blades, and work holder tooling, a specific sequence of removing and replacing items is preferred. The order of sequence was developed within and around the physical constraints of the stencil printer. It should be understood that the sequence of replacing items within the stencil printer disclosed herein can be adapted to suit any custom needs of the stencil printer or the movable cart.

The print head and the print head gantry are used to transfer and precisely position a tooling tray. The tooling tray is configured to hold the squeegee blades and the tooling used within the stencil printer. When the print head and the print head gantry position the tooling tray within the stencil printer using printer vision registration, the squeegee blades and the tooling can be transferred from or to the tooling tray using the printer print head gantry. In one embodiment, the imaging system, e.g., imaging system 30, can be used to take an image of the tooling tray and the determine the location of the tooling tray by using the printer vision registration software associated with the controller, e.g., controller 14.

A full stencil printer change of replaceable items requires removal of stencil and unloading squeegee blades and tooling from the stencil printer and subsequently loading new squeegee blades and tooling and inserting a new stencil into the printer. With reference to FIG. 5, which shows a method 500 that specifies a sequence of replacing items in the stencil printer, the order of sequence for the automated printer change of tooling is as follows. At 502, the existing stencil is removed from the stencil printer.

At 504, an empty tooling tray is inserted into the stencil printer using the print head and the print head gantry. The empty tooling tray may be presented to the stencil printer by the operator or by the movable cart. The position of the tooling tray is verified by using the vision registration verification software associated with the controller. As mentioned above, the imaging system can be employed to take an image of the empty tooling tray and send the image to the controller for verification.

After determining the location of the tooling tray, the front and rear squeegee blades and removed and placed into the tooling tray. Next the tooling is picked up and placed into the tooling tray by using tooling pins associated with the print head and the print head gantry. Once the squeegee blades and the tooling are placed in the tooling tray, the tooling tray is removed from the stencil printer.

At 506, a loaded tooling tray is inserted into the stencil printer using the print head and the print head gantry of the stencil printer. The loaded tooling tray may be presented to the stencil printer by the operator or by the movable cart. Specifically, the loaded tooling tray includes new front and rear squeegee blades and new tooling that are intended to replace the used squeegee blades and the used tooling that were previously removed from the stencil printer or any combination needed for the process. Next, the tooling tray is positioned within the stencil printer using the stencil printer vision registration verification software associated with the controller. As with positioning the empty tooling tray, the imaging system can be employed to take an image of the loaded tooling tray and send the image to the controller for verification.

Next, the new tooling is placed on the stencil printer work holder table, e.g., the support assembly 28, by using the tooling pins associated with the print head and the print head gantry of the stencil printer. Next, the new front and rear squeegee blades are picked up and installed on the print head. After installing the new tooling and squeegee blades, the tooling tray is removed from the stencil printer.

At 508, the new stencil is inserted into the stencil printer. The sequence of replacing items in the stencil printer is completed at this point.

The movable cart can be configured to present and remove stencils and tooling trays from the stencil printer. For example, in one embodiment, the stencil printer can be configured to move the stencil and the tooling tray to a suitable position in which the movable cart is configured to complete the removal. The stencil and/or the tooling tray can be moved and positioned within the stencil printer by the tooling pins associated with the print head and the print head gantry. Specifically, the tooling pins can be used to engage the stencil and/or the tooling tray to laterally move the stencil and/or tooling tray within the stencil printer.

Referring to FIG. 6, an empty tooling tray is indicated at 600. As shown, the tooling tray 600 includes a support 602 for front and rear squeegee blades. The tooling tray 600 further includes a support 604 for tooling.

Referring to FIG. 7, the tooling tray 600 is shown supporting front and rear squeegee blades, together indicated at 702 on support 602. The tooling tray 600 further is shown supporting tooling 704 on support 604. The tooling tray 600 can be configured to support any type of item requiring replacement within the stencil printer.

In some embodiments, the tooling tray 600 includes a rectangular or square frame and a planar body. The frame can be sized to replicate the frame of a stencil, e.g., stencil 18. The tooling tray 600 can be fabricated from lightweight yet strong material, such as an aluminum alloy. The body of the tooling tray 600 includes the support 602 for the squeegee blades and the support 604 for the tooling. As noted, the tooling tray 600 can be sized and shaped to be substantially the same in form-factor as a stencil to permit handling and storage/retrieval of the tooling tray in substantially the same manner as a stencil. For example, the tooling tray 600 can be customized for a certain size, e.g., 15 inch by 15 inch, 20 inch by 20 inch, 23 inch by 23 inch, and 29 inch by 29 inch. The stencil printer 205 and the movable cart 200 are particularly suited to handle stencils and tooling trays in a common manner. The movable cart 200 is configured to partially deliver the tooling tray 600 from the movable cart to the stencil printer 205, and the stencil printer is configured to receive the tooling tray the rest of the way. For example, a transport arm can be used to push the tooling tray 600 away from a carriage of the movable cart 200 and to retrieve the tooling tray into the movable cart.

In some embodiments, the tooling tray 600 can include fiducials, which can be viewed by the imaging system, e.g., imaging system 30 of the stencil printer 10, to establish alignment to the parts and locations on the tooling tray. A method of aligning and verifying the tooling tray 600 can be employed by capturing and analyzing fiducial locations.

Referring to FIG. 8, the print head assembly of the stencil printer, e.g., print head assembly 20, includes an end effector generally indicated at 800, which can be configured to pick up and release items from the tooling tray 600. As previously described, with stencil printer 10, the print head assembly 20 is mounted on the print head assembly gantry 22, which moves the print head assembly in the y-axis direction under the control of the controller 14. The print head assembly 20 is configured to move in the z-axis direction as described above.

In one embodiment, the end effector 800 can be configured to pick up and release squeegee blades 702. The end effector 800 is configured to engage and disengage the squeegee blades 702 without the aid of tools to attach and remove the squeegee blades from the print head assembly 20. In one embodiment, the tooling tray 600 can be configured with a spring-loaded locking mechanism to secure a squeegee blade holder of the squeegee blades 702 to the end effector 800 of the print head assembly 20. A method of passively picking up and dropping off squeegee blades 702 without needing additional axes or actuators can be performed by the end effector 800.

In one embodiment, the end effector 800 includes a rectangularly- shaped body 802 that is secured to the print head assembly 20 by a pair of connecting rods, each indicated at 804. The end effector 800 further can be configured with a pair of downwardly extending pins, which are configured to releasably secure the squeegee blades 702 in the manner shown in FIG. 8. The pins can also be used to manipulate a stencil and/or tooling tray by moving the stencil and/or tooling tray laterally within the stencil printer.

In some embodiments, the empty tooling tray and the loaded tooling tray can embody a single tooling tray that is configured to support new front and rear squeegee blades and new tooling and used squeegee blades and the used tooling that were previously removed from the stencil printer. In some embodiments, the movable cart 200 is configured to receive a tooling tray that is configured to store items, such as squeegee blades, tooling, and/or paste pans into cleaner in a desired position, such as a horizontal position.

In some embodiments, the movable cart includes a controller that is adapted to control the operation of the movable cart based on operational parameters obtained by the controller. The controller can be configured to communicate with the controller of the stencil printer and/or a controller associated with the production line. In one embodiment having multiple movable carts, the controller may embody a plurality of controllers provided in each movable cart that communicates with one another over a controller area network (CAN) Bus or other type of network. In other embodiments, a master controller may be provided to control the operation of the controllers of the movable carts. Each movable cart may be provided with a display, which is operably coupled to the controller. The display is adapted to display the operational parameters of the movable cart, such as, but not limited to, the number of clean and used stencils or items provided on tooling trays. Suitable monitors may be provided to acquire such information. Alternatively, or in addition to the foregoing embodiment, the operational parameters may be displayed on the display provided within the stencil printer, and/or a display associated with the production line.

In other embodiments, the movable cart may be controlled by the controller of the stencil printer and/or a controller associated with the production line. The controller can be a controller dedicated to one or more movable carts.

In some embodiments, material identification for items on the movable cart can include a device to manipulate the item and a scanner to scan and identify the item. In one embodiment, a barcode to identify the items can be implemented. For example, the barcode can include a ID scanner for UPC codes, a 2D scanner for QRC codes, a printed label applied on the item or a laser etched label etched on the item. In another embodiment, an RFID system to identify the items can be implemented. For example, the RFID system can include an RFID tag applied to the item and an RFID reader associated with the movable cart. With an RFID system, line-of-site between the reader and the item is not required. Moreover, scanning is not required to identify all items within the movable cart. In another embodiment, an imaging or vision system to identify the items can be implemented. The vision system could be an imaging system similar to the imaging system 30 associated with the stencil printer 10, and can be associated on the stencil printer, off the stencil printer or on the movable cart.

In some embodiments, a database is provided to keep track of items stocked on the movable cart. In one embodiment, the database may include an open application (App) architecture and be configured to push data to the stencil printer. The movable cart can be configured to communication with the stencil printer to push/pull data to stencil printer and/or the production line or configured to communicate with the production line directly. The database can include job information or material information. The database further can communicate with a manufacturing execution system (MES) associated with the production line, the stencil printer, or both. The MES system can be configured to know which materials are required for a production run. The movable cart can be configured to communicate with the MES system to adjust delivery of items to the stencil printer.

The database further can be configured to retrieve information about items based on identification, e.g., a barcode number. In one embodiment, a central management system can be provided in which the stencil printer and/or the movable cart is programmed to accept material coming from movable cart. The movable cart is programmed to update the database to identify the materials on the movable cart, load information into the database associated with the movable cart and/or the stencil printer from a network, which is tied back to the MES system.

The database further can be configured to store additional information, such as usage and consumption. The database can be configured to store information locally or remotely, and can be configured to store data associated with one or more production runs. For example, the database can be configured to obtain and store data including but not limited to traceability of stencils and/or tooling trays.

The database can be configured to share prediction data when replacement/replenishment is needed. For example, with respect to storing information related to stencils and/or tooling trays, the database can be configured to perform one or more operation. The database can be configured to share prediction data for other changeable/consumable items, such as for the stencils and/or tooling trays.

The database can be configured to store data associated with lot traceability. In addition, RFID or mechanical keying of a board or a stencil frame of the stencil is provided to ensure correct alignment/orientation/direction/front-back/top-bottom when these items are inserted into the stencil printer. This information can be used to verify correct orientation and/or fit before the items are transported from the warehouse and/or before the items are installed in the stencil printer. A low-cost reader can perform this function.

In some embodiments, the movable cart can be configured to store materials. The movable cart can be configured to be flexible to accommodate where the materials come from and where the materials go to. In addition, the movable cart can be configured to identify where a particular material is located on the movable cart. In certain embodiments, the location, whether by auto delivery or manual delivery, is remote, local, on the movable cart, and/or on the stencil printer.

In some embodiments, the movable cart can be configured to perform inventory control. Specifically, the movable cart can be configured to identify where material is located, how much material is used, how the material is used, when the material is used, tie the material and information about the material to a customer inventory control system, and track material type consumed per board or lots of boards.

In some embodiments, the movable cart can be configured to organize items stored on the movable cart. As mentioned above, in one embodiment, one movable cart can be provided to store, transport and deliver multiple resources, including but not limited to stencils and/or tooling trays. In another embodiment, the movable cart can be configured to store, transport and deliver a single resource or item to the stencil printer. For example, the movable cart can be configured to store multiple stencils and/or tooling trays. The movable cart can be configured to service multiple production lines. In another embodiment, the movable cart can be configured to service one stencil printer.

In some embodiments, the movable cart can be configured to transport items from the movable cart to the stencil printer and from the stencil printer to the movable cart, and be able to account for elevation differences between the movable cart and the stencil printer. The transportation can be automated or manual. In one embodiment, movable carl can be moved by automatically guided vehicle (AVG) technology associated with the movable cart or remotely controlled. In another embodiment, the movable cart can be configured to move autonomously. In another embodiment, the movable cart can be configured to be moved manually. In yet another embodiment, the movable cart can be configured to move items stored on the movable cart automatically and/or manually. For example, the movable cart can be configured to move items automatically, and can provide for an interruption of a pre-planned activity in which the items are moved manually.

In some embodiments, timing associated with performing transportation functions of the movable cart can be programmed to account for shift change, e.g., a personnel shift, scheduled maintenance, on demand activities, e.g., a recipe change, and predictive events (just-in-time replacements). The timing can be programmed to meet multiple line balance control requirements, with one or more movable carts and to meet real-time on- demand material supply demands on the production line.

In some embodiments, the movable cart is configured to perform inspection. For example, the movable cart can inspect on cart and off cart items including stencils and/or tooling trays. In one embodiment, a vision system associated with the movable cart can be configured to obtain images of the items. The vision system in conjunction with the controller, can be configured to inspect for cleanliness, damage, wear, and identification readability, e.g., is the barcode label worn, dirty or torn. The vision system can embody any type of 2D, 3D or color camera.

In some embodiments, the movable cart is configured to interface with the stencil printer, both from a mechanical interface and an electronics communication interface. In one embodiment, the movable cart can be configured with a unique mechanical interface that mates with a unique mechanical interface of the stencil printer. The unique mechanical interfaces can be geometric features. In another embodiment, the movable cart can be configured with pins that are received within guides associated with the stencil printer to register the movable cart with the stencil printer prior to fully docking the movable cart. The pins and guides can be reversed, with the pins provided on the stencil printer and the guides provided in the movable cart. Other types of guides can be used, such as electric al/magnetic guides, vision guides, sensors, latches, etc.

In some embodiments, the interface and the docking station can be configured with a clamping system to maintain the movable cart in place with respect to the stencil printer. For example, a magnetic clamping system can be employed.

In some embodiments, the stencil printer can be configured with multiple docking stations, e.g., five docking stations. The docking station can be provided at a front of the stencil printer or at a back of the stencil printer.

The movable cart and/or the stencil printer can be configured to verify whether the movable cart can be docked and interface with the stencil printer. In one embodiment, verification can be provided to confirm that the movable cart is in position and ready to interface with the stencil printer. This verification process can further determine whether correct materials are on the movable cart and whether the movable cart material information can be received from MES system, or locally identified. If not correct, the movable cart can be configured to activate an alarm and/or alert an operator if wrong or damaged materials are on the movable cart.

In some embodiments, the movable cart can be configured with actuation devices or actuators to move items onto and off of the movable cart once the movable cart is docked to the stencil printer. Embodiments of the actuators can be implemented on the movable cart, the stencil printer. In another embodiment, the items can be manually loaded and unloaded from the movable cart.

In some embodiments, the movable cart can be configured to interface with a production line. With this embodiment, the operator of the production line can confirm the correct location and acknowledge receipt of the movable cart on the stencil printer.

In some embodiments, the movable cart can be configured to communicate with the stencil printer, the production line, and/or select machines within the production line via an open platform. Communication systems can include a wired system, a wireless system (through a common network, mesh, Bluetooth, Wi-Fi, Zigbee, WAN, Nodes, Li- Fi, etc.), a combination of wired and wireless systems, and infrared (IR) system. In some embodiments, the movable cart can be configured with a dedicated power source. In one embodiment, the movable cart includes a battery configured to power automated components provided in the movable cart, e.g., mechanisms used to move stencils and/or tooling trays into and out of the movable cart. In other embodiments, the movable cart can be configured with an uninterruptible power supply. The power source can be configured to support actuation while “docked” (high-voltage from stencil printer when docked, otherwise low-voltage when undocked). The power source can be configured to recharge for autonomous operations, e.g., recharge a battery from power provided by the stencil printer.

In some embodiments, the movable cart can be configured to function with the stencil printer. For example, the movable cart can be configured to provide a handshaking function with the stencil printer 10 prior to a transfer of an item, e.g., “please give me stencil #1234.” The movable cart and the stencil printer can be configured with a communication protocol and/or a library reference on what is available to consume. The movable cart can be configured to determine whether the movable cart has correct items. The handshaking function can be configured to ensure the correct transfer of an item, e.g., “here’s stencil #1234,” and/or the subsequent transfer of an item, e.g., “I now have stencil #1234.” In one embodiment, a mobile device can be configured to scan and identify items in the movable cart, and determine, for example, whether the items are ready for use, require cleaning, etc.

In some embodiments, the movable cart can be configured to address errors associated with handling and recovering items in the movable cart. For example, the movable cart can be configured to detect an incomplete action by one party, an incomplete transfer of an item, e.g., a stuck or jammed item, a dropped transfer, e.g., “I passed stencil #1234 to you, don’t you have it?,” and a manual intervention or override, e.g., “here, let me help you.” In one embodiment, a controller associated with the movable cart can be configured to perform static discharge control, data recovery and/or security. In some embodiments, the movable cart can be configured with a higher level of capability. In addition to indexing all the equipment to the correct height, the movable carl would need to pull in/push out all equipment for machine gantries to attach.

In some embodiments, existing machine gantries, rails and print head of the stencil printer can be configured to shuttle items in and out.

In some embodiments, the movable cart can be configured to communication with the stencil printer, the production line and a warehouse associated with the production line.

In some embodiments, the movable cart can be configured with an electric al/pneumatic interface.

In some embodiments, the movable cart can be configured to track consumables - new and used on the movable cart, e.g., stencils and/or tooling trays, including location, temperature and other data.

In some embodiments, the movable cart can be configured to store and supply stencils and/or items on tooling trays for duration of a production run.

In some embodiments, the movable cart can be configured to scan all consumables with a suitable scanning device, such as a barcode reader or RFID reader.

In some embodiments, the movable cart can be configured with an indexing mechanism to properly locate consumables.

In some embodiments, the movable cart can be configured with a bypass switch to disconnect the movable cart from the stencil printer 10 if the movable cart has an issue.

In some embodiments, the movable cart can be configured to be moved manually or by an automated guided vehicle (AGV).

In some embodiments, the movable cart can be configured to dock and interface with the stencil printer.

In some embodiments, the movable cart can be configured to service multiple stencil printers.

In some embodiments, the movable cart can be configured to be dedicated to one consumable item, e.g., stencils, or multiple consumable/changeover items. In some embodiments, the movable cart can be configured to transport and present the consumables to be cleaned at a remote station.

In some embodiments, the movable call can be configured to be refilled at a stockroom associated with a warehouse.

In some embodiments, the movable cart can be configured to be climate controlled, either actively or passively.

In some embodiments, the movable cart can be configured be controlled by an application (App) capable for smartphone integration.

As used herein, an “automated” or “fully automated” changeover describes the replacement or replenishment of an item without human intervention.

As used herein, a “partially automated” changeover describes the replacement or replenishment of an item with some or limited human intervention.

As used herein, “transport” or “transporting” describes moving an item from one position to another, either manually or with a machine.

As used herein, “install” or “installing” describes the process of placing an item in a position ready for use.

As mentioned above, the movable cart can be employed to replace other items within the stencil printer. For example, the stencil wiper assembly includes consumables, e.g., paper and solvent, which can be automatically replaced by the movable cart.

The concepts disclosed herein may be employed in other types of equipment used to fabricate electronic substrates, including dispensers, pick-and-place machines, reflow ovens, wave soldering machines, selective solder machines, and inspection stations. For example, the concepts directed to replacing paste cartridges can be employed in dispensers used to dispense viscous material. In another example, the concepts directed to replacing tooling can be employed in dispensers and in pick-and-place machines used to mount electronic components onto electronic substrates. In another example, the concepts directed to replacing items can be employed in replacing solder within wave soldering and selective soldering machines and cleaning product within cleaning stations.

Having thus described several aspects of at least one embodiment, it is to be appreciated 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 the disclosure. Accordingly, the foregoing description and drawings are by way of example only.

What is claimed is: