System and method for replacing items within a stencil printer

Abstract

The method of replacing items in a stencil printer includes removing the used stencil from the stencil printer, inserting an empty tooling tray into the stencil printer, removing the used squeegee blade from the print head, positioning the used squeegee blade within the empty tooling tray, removing the used tooling from the support assembly, positioning the used tooling within the empty tooling tray, removing the tooling tray having the used squeegee blade and the used tooling from the stencil printer, inserting a loaded tooling tray into the stencil printer, wherein the loaded tooling tray has a new squeegee blade and new tooling, installing the new tooling on the support assembly, installing the new squeegee blade on the print head, removing the loaded tooling tray from the stencil printer, and installing a new stencil on the stencil printer.

Description

Technical Field

[0001] This application relates generally to stencil printers and related methods for printing a viscous material, such as solder paste, onto an electronic substrate, such as a printed circuit board (PCB), and more particularly to a system and method for exchanging items (articles, parts) within a stencil printer.

Background Art

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

[0003] In the above printer, when the circuit board is properly aligned with the stencil, the circuit board is raised up to the stencil and solder paste is ejected onto the stencil. A wiper blade (i.e., squeegee) traverses the stencil and extrudes the solder paste through the holes of the stencil onto the circuit board. As the squeegee moves across the stencil, the solder paste tends to spread out in front of the blade. This results in desirable mixing and shearing of the solder paste and a desired viscosity is obtained to facilitate filling the holes of the screen, i.e., the stencil. The solder paste is typically ejected from a standard cartridge onto the stencil. Thereafter, the stencil is separated from the circuit board, and most of the material remains on the circuit board by 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 further circuit boards are printed.

[0004] Another process when printing a circuit board involves inspecting the circuit board after the solder paste has been deposited on the surface of the circuit board. Inspecting the circuit board is important to determine if a clean electrical connection can be formed. Too much solder paste can cause a short circuit, while too little solder paste in the appropriate locations can prevent electrical contact. Generally, a vision inspection system is further utilized to provide a 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 switching, the operator has to perform many manual tasks such as changing the stencil, replacing the solder paste cartridge, replacing the squeegee blade, and replacing the support tooling. In each of these tasks, the operator has to perform the task manually. For example, in most stencil printers, the operator has to unlock the stencil, remove the stencil, properly insert the replacement stencil, and lock the replacement stencil in place. The switching operation can take about 30 minutes, during which the stencil printer is not operating, resulting in the PCB production line not running.

Summary of the Invention

[0006] One aspect of the present disclosure relates to a method for replacing items within a stencil printer. In one embodiment, the method includes removing a used stencil from the stencil printer, inserting an empty tooling tray into the stencil printer, removing a used squeegee blade from the print head of the stencil printer, positioning the used squeegee blade within the empty tooling tray, removing used tooling from the support assembly of the stencil printer, positioning the used tooling within the empty tooling tray, removing the tooling tray having the used squeegee blade and the used tooling from the stencil printer, inserting a loaded tooling tray into the stencil printer, wherein the loaded tooling tray has a new squeegee blade and new tooling, installing the new tooling on the support assembly of the stencil printer, installing the new squeegee blade on the print head of the stencil printer, removing the loaded tooling tray from the stencil printer, and installing a new stencil on the stencil printer.

[0007] The method embodiments can further include verifying the position of an empty tooling tray when inserting the empty tooling tray into the stencil printer. Verifying the position of the empty tooling tray can include capturing an image of the empty tooling tray and determining the position of the empty tooling tray using vision alignment verification software. Capturing an image of the empty tooling tray can be realized by the imaging system of the stencil printer. The vision alignment verification software may be associated with (attached to) the controller of the stencil printer. Inserting a loaded tooling tray into the stencil printer can include capturing an image of the loaded tooling tray and determining the position of the loaded tooling tray using vision alignment verification software. Capturing an image of the loaded tooling tray can be realized by the imaging system of the stencil printer. The vision alignment verification software may be associated with the controller of the stencil printer. Removing a used stencil, inserting an empty tooling tray, removing a tooling tray having a used squeegee blade and used tooling, inserting a loaded tooling tray, removing a loaded tooling tray, and installing a new stencil can be realized by using tooling pins associated with the print head and print head gantry of the stencil printer. A movable cart can be employed to pass and remove the stencil and tooling tray from the stencil printer. The movable cart can include an interface configured to interact with a docking station associated with the stencil printer. The empty tooling tray can include supports for a front squeegee blade and a rear squeegee blade and a support for the tooling. The method can be executed without the need for human intervention.The method can further 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.

[0008] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or substantially identical component shown in the various figures is represented by like reference numerals. For clarity, not all components may be labeled in all of the drawings.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

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Figure 8

Modes for Carrying Out the Invention

[0010] This disclosure relates generally to material application machines (referred to herein as "stencil printers", "screen printers", "printing machines", or "printers") and other equipment that are utilized in a surface mount technology (SMT) process line to apply assembly materials (e.g., solder paste, conductive ink, or encapsulation materials) onto a substrate (e.g., a printed circuit board referred to in this application (this document) as an "electronic substrate", "circuit board", "board", "PCB", "PCB substrate", "substrate", or "PCB board"), or to perform other operations such as inspection, rework, or placement of electronic components onto the substrate. Specifically, embodiments of this disclosure are described below with reference to a stencil printer used to fabricate printed circuit boards.

[0011] For purposes of illustration only and not of limitation, the present disclosure will now be described in detail with reference to the accompanying drawings. The present disclosure is not limited to the details of construction and the arrangement of components set forth in the following description or shown in the drawings with respect to its application. The principles described herein may be used in other embodiments and may be practiced or carried out in various ways. Also, the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. Any reference to an example, embodiment, component, element, or act of a system and method referred to herein in the singular is intended to include embodiments that include a plurality thereof, and any reference to a plurality of any embodiment, component, element, or act herein is intended to include embodiments that include only a single one thereof. References in the singular or plural are not intended to limit the systems or methods, their components, acts, or elements disclosed herein. Use of the terms “including,” “comprising,” “having,” “containing,” “involving,” and variations thereof herein is meant to encompass the item(s) listed before the term and their equivalents and additional items. References to “or / and” are to be construed as inclusive such that any term described using “or / and” can indicate any single one of the terms described, more than one of the terms described, and all of the terms described. Additionally, where there is inconsistency in the usage of terms between this application document and documents incorporated by reference as part of this application, the usage of terms in the documents incorporated by reference as part of this application is supplementary to the usage in this application document, and where the inconsistency causes a contradiction, the usage of terms in this application document is valid.

[0012] For purposes of illustration, embodiments of the present disclosure will be described below with reference to a stencil printer used to print an assembly material such as solder paste onto a circuit board. However, those skilled in the art will understand that the embodiments of the present disclosure are not limited to a stencil printer that prints solder paste onto a circuit board, but can be used in other applications that require the dispensing of other viscous assembly materials such as adhesives and encapsulation materials. For example, the apparatus can be used to print an epoxy used as an underfill for a chip scale package. Further, the stencil printer of the embodiments of the present disclosure is not limited to printing an assembly material onto a circuit board, but includes those used to print other materials onto various substrates such as semiconductor wafers. Also, the terms screen and stencil can be used interchangeably in the present application to describe devices within a printer that define a pattern to be printed on a substrate. In certain embodiments, the stencil printer can include the Momentum™ or Edison™ series of stencil printer platforms provided by ITW Electronic Assembly Equipment of Hopkinton, Massachusetts. An exemplary stencil printer is generally shown at 5 in FIG. 1. In this embodiment, the stencil printer 5 is an Edison™ series of stencil printer platforms provided by ITW Electronic Assembly Equipment of Hopkinton, Massachusetts.

[0013] Referring to FIG. 2, a stencil printer of an embodiment of the present disclosure is generally indicated at 10. As shown, the stencil printer 10 has a frame 12 that supports the components of the stencil printer. The components of the stencil printer can include, among other things, a controller 14, a display 16, a stencil 18, and a print head or print head assembly. The print head or print head assembly is generally indicated at 20 and is configured to apply solder paste in a manner described in more detail below.

[0014] As shown in FIG. 2 and as described below, the stencil and the print head assembly can be connected to the frame 12 as appropriate or otherwise connected. In one embodiment, the print head assembly 20 can be mounted on a print head assembly gantry 22, and the print head assembly gantry 22 can be mounted on the frame 12. The print head assembly gantry 22 enables the print head assembly 20 to move in the y-axis direction under the control of the controller 14 and to apply pressure to the print head assembly by engaging the stencil 18. In certain embodiments, the print head assembly 20 can be placed above the stencil 18 and lowered in the z-axis direction to contact the stencil and form a seal with the stencil.

[0015] The stencil printer 10 can also have a conveyor system having rails (not shown) for transporting a printed circuit board (which may be referred to herein as a "printed wiring board", "substrate", or "electronic substrate") 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 a circuit board to a working area of the stencil printer, which may be referred to herein as a "print nest", and to unload the circuit board from the print nest.

[0016] In addition, referring to FIG. 3, the stencil printer 10 has a support assembly 28 that supports a circuit board 29 (shown in dashed lines). The support assembly 28 raises and fixes the circuit board so that the circuit board is stable during the printing operation. In certain embodiments, the substrate support assembly 28 can further include a specific substrate support system, such as a rigid support, a plurality of pins, or flexible tooling, etc., and the substrate support system is positioned below the circuit board when the circuit board is in the printing position. The substrate support system can be used in part to support the internal region of the circuit board to prevent bending or warping of the circuit board during the printing operation.

[0017] In one embodiment, the print head assembly 20 can be configured to receive solder paste from a dispenser, such as a solder paste cartridge, etc., that provides the solder paste to the print head assembly during the printing operation. Instead of a cartridge, other methods of supplying solder paste may be utilized. For example, the solder paste can be manually deposited between the blades or from an external source. In addition, in certain embodiments, the controller 14 can use a personal computer having a suitable operating system, such as the Microsoft Windows® operating system provided by Microsoft Corporation, and be configured to control the operation of the stencil printer 10 using application-specific software. The controller 14 can be network-connected to a master controller used to control a production line for manufacturing circuit boards.

[0018] In one configuration, the stencil printer 10 operates as follows. The circuit board 29 is carried into the stencil printer 10 using a conveyor rail. The support assembly 28 raises and fixes the circuit board 29 to the printing position. Then, the print head assembly 20 is lowered in the z-axis direction until the blade of the print head assembly contacts the stencil 18 with a desired pressure. Then, the print head assembly 20 is 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 onto the circuit board 29 through the holes in the stencil 18. When the print head assembly completely traverses the stencil 18 across the holes, the print head assembly is lifted from the stencil and the circuit board 29 is lowered back onto the conveyor rail. The circuit board 29 is released and conveyed from the stencil printer 10, whereby a second circuit board can be carried into the stencil printer. To print on the second circuit board 29, the print head assembly is lowered in the z-axis direction to contact the stencil and is moved across the stencil 18 in the direction opposite to that used for the first circuit board.

[0019] An imaging system 30 can be provided for the purpose of aligning the stencil 18 with 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 connected to an imaging gantry 32 for moving the imaging system. In one embodiment, the imaging gantry 32 can be connected to the frame 12, has a beam extending between the side rails of the frame 12, and provides a reciprocating movement to the imaging system 30 above the circuit board 29 in the y-axis direction. The imaging gantry 32 can further include a carriage device for housing 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 for moving the imaging system 30 is known in the art of solder paste printing. The imaging system 30 can be positioned at any position below the stencil 18 and above the circuit board 29 such that images of predetermined regions of the circuit board or the stencil can be taken respectively.

[0020] After the solder paste has been applied to the circuit board one or more times, excess solder paste can accumulate on the bottom of the stencil 18, and a stencil wiper assembly generally indicated at 34 can move under the stencil to remove the excess solder paste. In other embodiments, the stencil 18 can move above the stencil wiper assembly.

[0021] As described above, conventionally, a stencil printer has required manual intervention to perform the replacement and / or replenishment operations of certain parts. For example, a typical stencil needs to be replaced after a certain period, e.g., after 4 hours. Also, the stencil needs to be replaced for separate production runs. In addition, the solder paste cartridge that supplies the temperature-controlled solder paste to the stencil printer needs to be replaced over time, e.g., within 4 hours. Different types of solder paste materials may be required for separate production runs. Another item that requires regular replacement is the squeegee blade, which wears out during use. And finally, the tooling used to support the substrate at the printing position is replaced when changing from one production item to another.

[0022] In one embodiment, a method for replacing a stencil and / or item disposed on a tooling tray may include providing a clean stencil and / or item on a movable cart when a new stencil and / or item on the tooling tray is requested for a new production run or due to wear of an existing stencil and / or item. In 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 fixed for use. The dirty stencil and / or item is transported to a cleaning station that prepares the stencil and / or item for reuse by cleaning it. Once cleaned, the stencil and / or item can be transported back to the stencil printer or a storage room, and the stencil and / or item can be reused during the same or different production runs.

[0023] Embodiments of the present disclosure relate to a delivery system configured to automate or partially automate a switching process for a stencil printer and to implement one or more of the methods described herein. In one embodiment, the delivery system has a movable cart configured to engage with a stencil printer and to supply and receive replacement and replenishment parts and materials to and from the stencil printer. For example, the stencil printer can have a docking station configured to receive the movable cart. The docking station can have an interface that enables the movable cart to communicate with the stencil printer. A single movable cart can be configured to have switching stencils and / or replacement stencils. During switching, for example, the stencil printer must be reconfigured to produce different items. Thus, a new stencil can be utilized within the stencil printer to produce different products.

[0024] The switching process described herein can be realized by a single movable cart configured to exchange and / or replenish each item. In other embodiments, two or more movable carts can be provided. For example, for stencil switching, 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 stencils, store stencils, transport stencils to and from the stencil printer, inspect stencils, and interface with the stencil printer. The movable cart can also be configured to remove used parts, such as stencils, from the stencil printer.

[0025] Embodiments of the present disclosure further relate to a delivery system configured to automate a replenishment process for a stencil printer. In one embodiment, the delivery system has a movable cart configured to engage a stencil printer and supply and receive replacement and replenishment parts and materials to and from the stencil printer. For example, the stencil printer can have a docking station configured to receive the movable cart. The docking station can have an interface that enables the movable cart to communicate with the stencil printer. A single movable cart can be configured to have a switching stencil and a replacement stencil.

[0026] The replenishment process described in the present application may be implemented by a single movable cart configured to replenish replenishable items. In other embodiments, two or more movable carts may be provided. For example, for stencil replenishment, the movable cart is configured to support a plurality of replacement solder paste cartridges. The movable cart and / or the stencil printer may be configured to identify, store, transport to and from the stencil printer, inspect, and interface with the stencil printer a replacement solder paste cartridge.

[0027] Referring to FIG. 4, a movable cart generally designated 200 in an embodiment of the present disclosure removes and replaces items such as stencils, squeegee blades, and tooling from a stencil printer generally designated 205 and delivers the items to, for example, a cleaning station. When new items are required for a new production run or due to wear of existing items, clean items are conveyed by the movable cart 200 to the stencil printer 205. "Dirty" or used items are removed from the stencil printer 205, and "clean" or new items are inserted into and secured in the stencil printer for use. The dirty items are removed from the stencil printer 205 and new items are replaced within the stencil printer. These functions may be performed by the movable cart 200.

[0028] Similar to the stencil printer 10, the stencil printer 205 may be configured to include a docking station 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 may be configured with a mating interface designed to dock within the docking station provided in the stencil printer 205. This configuration is such that the movable cart 200 is configured to dock within the docking station of the stencil printer 205 from both the mechanical interface and the electronic device communication interface. The movable cart 200 may be configured with a unique mechanical interface that mates with the unique mechanical interface of the stencil printer 205. The unique mechanical interface may include geometric features. The movable cart 200 may be configured with pins that can be received within a guide associated with the stencil printer 205 to align the movable cart with the stencil printer in order to fully dock the movable cart. Other types of guides such as electrical / magnetic guides, visual guides, sensors, latches, etc. may be used.

[0029] Referring to FIG. 5, a sequence for exchanging items within a stencil printer, such as the stencil printer 205, is shown and described below. In order to efficiently utilize the capabilities of the stencil printer for the automated replacement of stencils, squeegee blades, and work holder tooling, the removal and replacement of specific sequences of items is preferred. The order of the sequence is developed within and around the physical constraints of the stencil printer. It should be understood that the sequence for exchanging items within the stencil printer disclosed in the present application can be adapted to any custom needs of the stencil printer or the movable cart.

[0030] The print head and print head gantry are used to transfer and accurately position the tooling tray. The tooling tray is configured to hold squeegee blades and tooling used within a stencil printer. When the print head and print head gantry use printer vision alignment to position the tooling tray within the stencil printer, the squeegee blades and tooling can be transferred from or to the tooling tray using the printer print head gantry. In one embodiment, an imaging system, such as imaging system 30, is used to take an image of the tooling tray, and the location of the tooling tray can be determined by using printer vision alignment software associated with a controller, such as controller 14.

[0031] Changing the replaceable items of a complete stencil printer requires removing the stencil, removing the squeegee blades and tooling from the stencil printer, subsequently loading new squeegee blades and tooling, and inserting a new stencil into the printer. Referring to FIG. 5 showing a method 500 for defining the sequence of exchanging items within a stencil printer, the sequence order for an automated printer tooling change is as follows. At 502, the existing stencil is removed from the stencil printer.

[0032] 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 passed to the stencil printer by an operator or may be passed to the stencil printer by a movable cart. The position of the tooling tray is verified by using vision alignment verification software associated with the controller. As described above, an imaging system may be employed to take an image of the empty tooling tray and transmit the image to the controller for verification.

[0033] After determining the location of the tooling tray, the front and rear squeegee blades are removed and placed within the tooling tray. Next, the tooling is picked up and placed within the tooling tray by using tooling pins associated with the print head and the print head gantry. When the squeegee blades and the tooling are placed in the tooling tray, the tooling tray is removed from the stencil printer.

[0034] At 506, the 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 passed to the stencil printer by an operator or may be passed to the stencil printer by a movable cart. Specifically, the loaded tooling tray includes new front and rear squeegee blades and a new tooling intended to replace the used squeegee blades and the used tooling previously removed from the stencil printer, or any combination required for the process. Next, the tooling tray is positioned within the stencil printer by using vision alignment verification software of the stencil printer associated with the controller. Similar to the positioning of the empty tooling tray, an imaging system may be employed to take an image of the loaded tooling tray and transmit the image to the controller for verification.

[0035] Next, a new tooling is placed on the workholder table of the stencil printer, such as on the support assembly 28, by using tooling pins associated with the print head and the print head gantry of the stencil printer. Next, 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.

[0036] At 508, a new stencil is inserted into the stencil printer. At this point, the sequence of exchanging items in the stencil printer is completed.

[0037] The movable cart may be configured to pass the stencil and the tooling tray and remove them from the stencil printer. For example, in one embodiment, the stencil printer may be configured to move the stencil and the tooling tray to an appropriate position where the movable cart can complete the removal. The stencil and / or the tooling tray may be moved and positioned within the stencil printer by tooling pins associated with the print head and the print head gantry. Specifically, the tooling pins may be engaged with the stencil and / or the tooling tray and used to move the stencil and / or the tooling tray laterally within the stencil printer.

[0038] Referring to FIG. 6, an empty tooling tray is shown at 600. As shown, the tooling tray 600 includes supports 602 for the front and rear squeegee blades. The tooling tray 600 further includes a support 604 for the tooling.

[0039] Referring to FIG. 7, the tooling tray 600 is shown in a state of supporting a front squeegee blade and a rear squeegee blade, indicated at 702, on a support portion 602. The tooling tray 600 is further shown in a state of supporting a tooling 704 on a support portion 604. The tooling tray 600 may be configured to support any type of item that needs to be replaced within the stencil printer.

[0040] In some embodiments, the tooling tray 600 includes a rectangular or square frame and a planar body. The frame may be sized to replicate the frame of a stencil, such as stencil 18. The tooling tray 600 may be made of a lightweight yet strong material such as an aluminum alloy. The body of the tooling tray 600 includes a support portion 602 for the squeegee blade and a support portion 604 for the tooling. As described above, the tooling tray 600 may be sized and shaped to have substantially the same form factor as the stencil to enable handling and storage / retrieval of the tooling tray in substantially the same manner as the stencil. For example, the tooling tray 600 may be customized to a particular size, such as 15 inches (about 38.1 cm) × 15 inches (about 38.1 cm), 20 inches (about 50.8 cm) × 20 inches (about 50.8 cm), 23 inches (about 58.4 cm) × 23 inches (about 58.4 cm), and 29 inches (about 73.7 cm) × 29 inches (about 73.7 cm). The stencil printer 205 and the mobile cart 200 are particularly suitable for handling the stencil and the tooling tray in a common manner. The mobile cart 200 is configured to partially deliver the tooling tray 600 from the mobile cart to the stencil printer 205, and the stencil printer is configured to receive the remaining portion of the tooling tray. For example, a transport arm may be used to push the tooling tray 600 away from the carriage of the mobile cart 200 and to retrieve the tooling tray into the mobile cart.

[0041] In some embodiments, the tooling tray 600 may include fiducials that can be viewed by the imaging system of the stencil printer 10, such as the imaging system 30, to establish alignment between the parts and the locations on the tooling tray. A method of aligning and verifying the tooling tray 600 by capturing and analyzing the location of the fiducials may be employed.

[0042] Referring to FIG. 8, the print head assembly of the stencil printer, such as the print head assembly 20, generally includes an end effector 800, which may be configured to pick up and release items from the tooling tray 600. As described above, in the stencil printer 10, the print head assembly 20 is mounted on a print head assembly gantry 22 that 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.

[0043] In one embodiment, the end effector 800 may be configured to pick up and release the squeegee blade 702. The end effector 800 is configured to engage and disengage the squeegee blade 702 without the assistance of tools to attach and remove the squeegee blade from the print head assembly 20. In one embodiment, the tooling tray 600 may be configured with a spring-biased locking mechanism for fixing the squeegee blade holder of the squeegee blade 702 to the end effector 800 of the print head assembly 20. A method of passively picking up and dropping off the squeegee blade 702 without requiring additional axes or actuators may be performed by the end effector 800.

[0044] In one embodiment, the end effector 800 includes a rectangular body 802 that is fixed to the print head assembly 20 by pairs of connecting rods, each indicated at 804. The end effector 800 may further be configured with a pair of downwardly extending pins configured to releasably secure the squeegee blade 702 in the manner shown in FIG. 8. The pins may also be used to manipulate the stencil and / or tooling tray by moving it laterally within the stencil printer.

[0045] In some embodiments, the empty tooling tray and the loaded tooling tray may embody a single tooling tray configured to support a new front squeegee blade and rear squeegee blade and new tooling, as well as used squeegee blades and used tooling previously removed from the stencil printer.

[0046] In some embodiments, the movable cart 200 is configured to receive a tooling tray configured to store items such as squeegee blades, tooling, and / or paste pans at a desired location, such as a horizontal position, within the cleaner.

[0047] In some embodiments, the movable cart has a controller, and the controller is adapted to control the operation of the movable cart based on the operation parameters obtained by the controller. The controller can be configured to communicate with the controller of the stencil printer and / or the controller associated with the production line. In one embodiment having a plurality of movable carts, the controller can embody a plurality of controllers provided in each movable cart that communicate with each other via a Controller Area Network (CAN) bus or other types of networks. In other embodiments, a master controller can be provided to control the operation of the controller of the movable cart. Each movable cart can be provided with a display operably connected to the controller. The display is adapted to display the operation parameters of the movable cart, such as, but not limited to, a clean stencil and the number of items provided on the used stencil or the tooling tray. To obtain such information, a suitable monitor can be provided. Alternatively, or in addition to the foregoing embodiments, the operation parameters may be displayed on a display provided in the stencil printer and / or a display associated with the production line.

[0048] In other embodiments, the movable cart can be controlled by the controller of the stencil printer and / or the controller associated with the production line. The controller can be a controller dedicated to one or more movable carts.

[0049] In some embodiments, the material identification for items on the mobile cart can include a device for manipulating the items and a scanner for scanning and identifying the items. In one embodiment, a barcode for identifying the items can be implemented. For example, the barcode can include a 1D scanner for UPC codes, a 2D scanner for QR codes, a printed label attached to the item, or a laser etching label etched on the item. In another embodiment, an RFID system for identifying the items can be implemented. For example, the RFID system can include an RFID tag attached to the item and an RFID reader associated with the mobile cart. By using the RFID system, a line-of-site between the reader and the item is not required. Also, scanning for identifying all items within the mobile cart is not required. In another embodiment, an imaging or vision system for identifying the items can be implemented. The vision system can be a similar imaging system as the imaging system 30 associated with the stencil printer 10 and can be associated on the stencil printer, outside the stencil printer, or on the mobile cart.

[0050] In some embodiments, a database is provided to track items stocked on a movable cart. In one embodiment, the database can include an open application (App) architecture and can be configured to push data to a stencil printer. The movable cart can be configured to communicate with the stencil printer to push / pull data to / from the stencil printer and / or the production line, or can be configured to communicate directly with the production line. The database can include job information or material information. The database can further 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 coordinate the delivery of items to the stencil printer.

[0051] The database can be further configured to retrieve information about items based on identification information, such as a barcode number. In one embodiment, a central management system can be provided that programs the stencil printer and / or the movable cart to receive materials from the movable cart. The movable cart is programmed to update the database to identify materials on the movable cart and to load information from the network into a database associated with the movable cart and / or the stencil printer, and the information is further associated with the MES system.

[0052] The database can be further configured to store additional information, such as usage and consumption amounts. 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 acquire and store data including, but not limited to, the traceability of stencils and / or tooling trays.

[0053] The database can be configured to share prediction data when exchange / supplementation is necessary. For example, for storing information regarding stencils and / or tooling trays, the database can be configured to perform one or more operations. The database can be configured to share prediction data for other changeable / consumable items such as stencils and / or tooling trays.

[0054] The database can be configured to store data associated with lot traceability. In addition, when these items are inserted into the stencil printer, an RFID on the plate or mechanical keying or the stencil frame of the stencil is provided so that the alignment, orientation, direction, front-back, top-bottom (up-down) are surely correct. This information can be used to verify the correct orientation and / or fitting before the item is transported from the warehouse and / or before the item is installed on the stencil printer. This function can be executed by a low-cost reader.

[0055] In some embodiments, the movable cart can be configured to store materials. The movable cart can be configured to have flexibility to adapt to where the materials come from and where the materials go. In addition, the movable cart can be configured to identify where on the movable cart a particular material is located. In a particular embodiment, the location is remote, local, on the movable cart, and / or on the stencil printer, regardless of whether it is an automatic delivery or a manual delivery.

[0056] In some embodiments, the movable cart can be configured to perform inventory management. Specifically, the movable cart can identify where the materials are located, how much the materials are used, how the materials are used, and when the materials are used, associate the materials and information about the materials with a customer inventory management system, and be configured to track the type of material consumed per panel or per lot of panels.

[0057] In some embodiments, the mobile cart can be configured to organize items stored on the mobile cart. As described above, in one embodiment, without limitation, one mobile cart can be provided to store, transport, and deliver a plurality of resources including stencils and / or tooling trays. In another embodiment, the mobile cart can be configured to store a single resource or item and transport and deliver it to a stencil printer. For example, the mobile cart can be configured to store a plurality of stencils and / or tooling trays. The mobile cart can be configured to serve multiple production lines. In another embodiment, the mobile cart can be configured to serve one stencil printer.

[0058] In some embodiments, the mobile cart can be configured to transport items from the mobile cart to the stencil printer and from the stencil printer to the mobile cart, and can be configured to take into account the elevation difference between the mobile cart and the stencil printer. The transportation can be automated or manual. In one embodiment, the mobile cart can be moved by automated guided vehicle (AGV) technology associated with the mobile cart or can be remotely controlled. In another embodiment, the mobile cart can be configured to move autonomously. In another embodiment, the mobile cart can be configured to be moved manually. In yet other embodiments, the mobile cart can be configured to automatically and / or manually move items stored on the mobile cart. For example, the mobile cart can be configured to automatically move items and can be prepared for interruptions to pre-planned activities in which items are moved manually.

[0059] In some embodiments, the timing associated with the execution of the transport function of the mobile cart can be programmed to take into account shift changes, such as the operator's shift, scheduled maintenance, on-demand activities, such as recipe changes, and precursor events (just-in-time replacement). The timing can be programmed to meet multiple line balance control requirements using one or more mobile carts and to meet the demand for real-time on-demand material supply on the production line.

[0060] In some embodiments, the mobile cart is configured to perform inspections. For example, the mobile cart can inspect items on and off the cart, including stencils and / or tooling trays. In one embodiment, the vision system associated with the mobile cart can be configured to obtain an image of the item. The vision system in conjunction with the controller can be configured to inspect for cleanliness, damage, wear, and readability of identification information, such as whether a barcode label is worn, not clean, or torn. The vision system can embody any type of 2D, 3D, or color camera.

[0061] In some embodiments, the movable cart is configured to interface with the stencil printer from both a mechanical interface and an electrical communication interface. In one embodiment, the movable cart can be configured to have a unique mechanical interface that mates with the unique mechanical interface of the stencil printer. The unique mechanical interface can be a geometric feature. In another embodiment, the movable cart can be configured to have pins that are received within a guide associated with the stencil printer to align the movable cart with the stencil printer before fully docking the movable cart. The pins and the guide can be reversed, with the pins provided on the stencil printer and the guide provided within the movable cart. Other types of guides can be used, such as electrical / magnetic guides, visual guides, sensors, latches, etc.

[0062] In some embodiments, the interface and docking station can be configured to have a clamping system that holds the movable cart in place relative to the stencil printer. For example, a magnetic clamping system can be utilized.

[0063] In some embodiments, the stencil printer can be configured to have a plurality of docking stations, for example, five docking stations. The docking stations can be provided at the front of the stencil printer or at the rear of the stencil printer.

[0064] The movable cart and / or the stencil printer can be configured to verify whether the movable cart can dock and interface with the stencil printer. In one embodiment, the verification can be provided to confirm whether the movable cart is in the appropriate position and ready to interface with the stencil printer. This verification process can further determine whether the correct material is on the movable cart and whether the movable cart material information can be received from the MES system or locally identified. If not, the movable cart can be configured to activate an alarm and / or warn the operator if incorrect or damaged material is on the movable cart.

[0065] In some embodiments, the movable cart can be configured to have an actuating device or actuator that moves items onto and off of the movable cart when the movable cart is docked to the stencil printer. Embodiments of the actuator can be implemented on the movable cart, the stencil printer. In another embodiment, the items can be manually loaded and unloaded with respect to the movable cart.

[0066] In some embodiments, the movable cart can be configured to interface with the production line. According to this embodiment, the operator of the production line can confirm the correct location of the movable cart on the stencil printer and be aware of the acceptance.

[0067] In some embodiments, the mobile cart can be configured to communicate with a stencil printer, a production line, and / or selected machines within the production line via an open platform. The communication system can include a wired system, a wireless system (via a common network, mesh, Bluetooth®, Wi-Fi, Zigbee®, WAN, Nodes, Li-Fi, etc.), a combination of wired and wireless systems, and an infrared (IR) system.

[0068] In some embodiments, the mobile cart can be configured to have a dedicated power source. In one embodiment, the mobile cart has a battery configured to power automated components provided within the mobile cart, such as a mechanism used to move a stencil and / or a tooling tray in and out of the mobile cart. In other embodiments, the mobile cart can be configured to have an uninterruptible power supply. The power source can be configured to support operation while "docked" (high voltage from the stencil printer when docked, low voltage when undocked). The power source can be configured to recharge for autonomous operation, for example, recharge the battery from the power provided by the stencil printer.

[0069] In some embodiments, the movable cart can be configured to function with a stencil printer. For example, the movable cart can be configured to provide a handshake function with the stencil printer 10, such as "Please give me stencil #1234", before transferring an item. The movable cart and the stencil printer can be configured to have a communication protocol and / or a library reference regarding what is consumable. The movable cart can be configured to determine whether the movable cart has the correct item. The handshake function can be configured to ensure the correct transfer of the item, such as "Here is stencil #1234", and / or to ensure the subsequent transfer of the item, such as "I have stencil #1234". In one embodiment, the mobile device can be configured to scan and identify the items within the movable cart and to determine, for example, whether the items are ready for use, whether cleaning is required, etc.

[0070] In some embodiments, the movable cart can be configured to handle errors related to the handling and removal of items within the movable cart. For example, the movable cart can be configured to detect incomplete actions by a party, incomplete transfer of items, such as snagging or jamming of items, dropping of transferred items, such as "I passed you stencil #1234, do you have it?", and manual intervention or manual override, such as "Let me help". In one embodiment, the controller associated with the movable cart can be configured to perform electrostatic discharge control, data recovery, and / or protection.

[0071] In some embodiments, the movable cart can be configured to have higher capabilities. In addition to indexing all devices to the correct height, the movable cart may need to pull in / push out all devices for attaching a machine gantry.

[0072] In some embodiments, the existing machine gantry, rails, and print heads of the stencil printer can be configured to load and unload items.

[0073] In some embodiments, the movable cart can be configured to communicate with the stencil printer, the production line, and the warehouse associated with the production line.

[0074] In some embodiments, the movable cart can be configured to have an electrical / air interface.

[0075] In some embodiments, the movable cart can be configured to track new and used consumables on the movable cart, such as stencils and / or tooling trays, including location, temperature, and other data.

[0076] In some embodiments, the movable cart can be configured to store and supply items on the stencil and / or tooling tray over the duration of the production run.

[0077] In some embodiments, the movable cart can be configured to scan all consumables using a suitable scanning device such as a barcode reader or RFID reader.

[0078] In some embodiments, the movable cart can be configured to have an indexing mechanism to properly position the consumables.

[0079] In some embodiments, the movable cart can be configured to have a bypass switch to disconnect the movable cart from the stencil printer 10 if there is a problem with the movable cart.

[0080] In some embodiments, the movable cart can be configured to be moved by a manual or an automated guided vehicle (AGV).

[0081] In some embodiments, the movable cart can be configured to dock and interface with a stencil printer.

[0082] In some embodiments, the movable cart can be configured for use with multiple stencil printers.

[0083] In some embodiments, the movable cart can be configured to be dedicated to one consumable item, such as a stencil, or multiple consumable / switching items.

[0084] In some embodiments, the movable cart can be configured to transport and deliver consumables to be cleaned at a remote station.

[0085] In some embodiments, the movable cart can be configured to be replenished in a storage room associated with a warehouse.

[0086] In some embodiments, the movable cart can be configured to be actively or passively environmentally controlled.

[0087] In some embodiments, the movable cart can be configured to be controlled by a smartphone-integratable application (App).

[0088] As used herein, "automated" or "fully automated" switching describes the replacement or replenishment of items without human intervention.

[0089] As used herein, "partially automated" switching describes the replacement or replenishment of items with some or limited human intervention.

[0090] As used herein, "transport" or "transporting" describes moving an item from one location to another, either manually or using a machine.

[0091] As used herein, "install" or "installing" describes the process of placing an item in a location where it is ready for use.

[0092] As described above, the mobile cart can be used to replace other items within the stencil printer. For example, the stencil wiper assembly includes consumables such as paper and solvent that can be automatically replaced by the mobile cart.

[0093] The concepts disclosed herein may be utilized in other types of equipment used to fabricate electronic substrates, including dispensers, pick-and-place machines, reflow ovens, wave soldering machines, selective soldering machines, and inspection stations. For example, the concept related to the replacement of a paste cartridge can be utilized in a dispenser used to dispense a viscous material. In another example, the concept related to the replacement of a tooling can be utilized in a dispenser and a pick-and-place machine used to attach electronic components to an electronic substrate. In another example, the concept related to the replacement of an item can be utilized in the replacement of solder within a wave soldering machine and a selective soldering machine, and in the cleaning of products within a cleaning station.

[0094] Thus, although some aspects of at least one embodiment have been described, it is understood that various modifications, variations, and improvements will readily occur to those skilled in the art. Such modifications, variations, and improvements are intended to be part of this disclosure and are intended to be within the scope of this disclosure. Accordingly, the foregoing description and drawings are by way of example only.

Claims

1. A method for replacing items in a stencil printer, comprising: removing a used stencil from the stencil printer; inserting an empty tooling tray into the stencil printer; removing a used squeegee blade from the print head of the stencil printer; positioning the used squeegee blade within the empty tooling tray; removing a used tooling from the support assembly of the stencil printer; positioning the used tooling within the empty tooling tray; removing the tooling tray having the used squeegee blade and the used tooling from the stencil printer; inserting a loaded tooling tray having a new squeegee blade and new tooling into the stencil printer; installing the new tooling on the support assembly of the stencil printer; installing the new squeegee blade on the print head of the stencil printer; removing the loaded tooling tray from the stencil printer; installing a new stencil on the stencil printer. A method as described above.

2. The method according to claim 1, wherein inserting the empty tooling tray into the stencil printer includes verifying the position of the empty tooling tray.

3. The method according to claim 2, wherein verifying the position of the empty tooling tray includes capturing an image of the empty tooling tray and determining the position of the empty tooling tray using visual alignment verification software.

4. The method according to claim 3, wherein capturing an image of the empty tooling tray is realized by an imaging system of the stencil printer.

5. The method according to claim 3, wherein the visual alignment verification software is associated with a controller of the stencil printer.

6. Inserting the loaded tooling tray into the stencil printer includes capturing an image of the loaded tooling tray and determining the position of the loaded tooling tray using vision alignment verification software, the method according to claim 2.

7. Capturing an image of the loaded tooling tray is realized by the imaging system of the stencil printer, the method according to claim 6.

8. The vision alignment verification software is associated with the controller of the stencil printer, the method according to claim 6.

9. Removing the used stencil, inserting the empty tooling tray, removing the tooling tray having the used squeegee blade and the used tooling, inserting the loaded tooling tray, removing the loaded tooling tray, and installing the new stencil are realized by using the tooling pins associated with the print head and the print head gantry of the stencil printer, the method according to claim 1.

10. A movable cart is employed to pass and remove the stencil and the tooling tray from the stencil printer, the method according to claim 1.

11. The movable cart includes an interface, and the interface is configured to interact with a docking station associated with the stencil printer, the method according to claim 10.

12. The empty tooling tray includes supports for a front squeegee blade and a rear squeegee blade and a support for tooling, the method according to claim 1.

13. The method is executed without the need for human intervention, the method according to claim 1.

14. The method according to claim 1 further includes 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.

15. The empty tooling tray and the loaded tooling tray embody a single tooling tray, the method according to claim 1.

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