Multifunctional print head for stencil printers

Abstract

A stencil printer comprises a frame, a stencil coupled to the frame, and a support assembly coupled to the frame, wherein the support assembly comprises a tool configured to support an electronic board at a printing position below the stencil. The stencil printer further comprises a print head assembly coupled to the frame in a manner configured to traverse the stencil during a printing stroke. The print head assembly comprises a squeegee blade assembly for applying solder paste onto the stencil and at least one paste cartridge. The stencil printer further comprises an end effector configured to pick up and release items from a tool tray. The stencil printer further comprises a movable cart configured to interface with the stencil printer to transport items for switching and / or replacement within the stencil printer.

Description

Technology Field

[0001] Cross-reference of related applications

[0002] The present application is based on, pursuant to 35 USC § 119(e), jointly pending U.S. Provisional Application No. 62 / 931,496, filed November 6, 2019, titled "MULTI-FUNCTIONAL PRINT HEAD FOR A STENCIL PRINTER"; U.S. Provisional Application No. 62 / 861,025, filed June 13, 2019, titled "METHOD AND SYSTEM FOR AUTOMATED CHANGEOVER AND REPLACEMENT WITHIN A STENCIL PRINTER"; U.S. Provisional Application No. 62 / 861,031, filed June 13, 2019, titled "AUTOMATED PRINTER ROBOTIC ARM"; and 2019 Claiming benefit of U.S. Provisional Patent Application No. 62 / 861,035, entitled AUTOMATED PRINTER SMART CART, filed on June 13, [Year], these applications are incorporated herein by reference in their entirety for all purposes.

[0003] Technology field

[0004] The present application generally relates to a stencil printer and a related method for printing a viscous material, e.g., solder paste, on an electronic substrate, e.g., a printed circuit board (PCB), and more specifically, to a system and method for fully automating such a stencil printer and method. Background Technology

[0005] In the manufacture of surface-mount printed circuit boards, a stencil printer may be used to print solder paste onto a circuit board. Typically, a circuit board having a pattern of pads or several other conductive surfaces on which the solder paste is to be placed is automatically fed into the stencil printer; before printing the solder paste onto the circuit board, 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. In some systems, an optical alignment system employing a vision system is used to align the circuit board with the stencil.

[0006] Once the circuit board is properly aligned with the stencil inside the printer, the circuit board is raised onto the stencil, solder paste is dispensed onto the stencil, and a wiper blade (or squeegee) moves across the stencil to force the solder paste through the holes in the stencil and onto the circuit board. As the squeegee moves across the stencil, the solder paste tends to roll in front of the blade, which induces mixing and shearing of the solder paste to facilitate filling the holes in the screen or stencil by achieving the desired viscosity. The solder paste is typically dispensed onto the stencil from a standard cartridge. Then, the stencil is separated from the circuit board, and most of the material remains on the circuit board due to adhesion between the circuit board and the solder paste. The material remaining on the surface of the stencil is removed in a cleaning process before additional circuit boards are printed.

[0007] Another process in circuit board printing involves inspecting the circuit board after solder paste has been applied to the surface of the circuit board. Inspecting the circuit board is important for determining whether a reliable electrical connection can be made. Excess solder paste can cause a short circuit, whereas too little solder paste in the proper locations can hinder electrical contact. Typically, a vision inspection system is additionally employed to provide two-dimensional or three-dimensional inspection of the solder paste on the circuit board.

[0008] Modern stencil printers require manual intervention to perform routine operations. For example, during a changeover, operators must perform many manual tasks, such as changing stencils, replacing solder paste cartridges, replacing squeegee blades, and replacing support tools. Each of these tasks requires the operator to perform the work manually. For instance, according to most stencil printers, the operator must unlock the stencil, remove the stencil, properly insert the replacement stencil, and lock the replacement stencil in place. Changeover operations can take up to 30 minutes, during which time the stencil printer does not operate, which may cause the PCB manufacturing line to stop functioning.

[0009] Additionally, the stencil printer requires manual intervention to perform replacement and / or replenishment operations. For example, the solder paste cartridge that supplies temperature-controlled solder paste to the stencil printer must be replaced after, for example, four hours or less. Items that are generally prone to wear, such as squeegee blades and stencils, may need to be replaced periodically if damaged.

[0010] One aspect of the present disclosure relates to a transport system configured to transport conversion and / or replacement items within a stencil printer. In one embodiment, the transport system comprises a frame and a translationally movable transport unit comprising one or more support structures configured to support one or more items. The translationally movable transport unit is coupled to the frame and moves perpendicularly to the frame, and the translationally movable transport unit is configured to transport one or more items to the stencil printer at a desired height.

[0011] In one embodiment, the translationally movable transporter may include a rectangular structure having an upper, lower, opposing side, open front, and open rear. The side of the structure may include slots, each slot configured to receive and support the opposing edge of a flat item comprising either a stencil or a tool tray. The translationally movable transporter further includes four vertically oriented rods located at the four corners of the structure, two upper bar members, one bar member fixed to the upper part of the structure adjacent to the open front of the structure and the other bar member fixed to the upper part adjacent to the open rear, and two lower bar members, one bar member fixed to the lower part of the structure adjacent to the open front of the structure and the other bar member fixed to the lower part adjacent to the open rear. Each bar member may include two openings formed at the opposing ends of the bar, and the openings are positioned to receive individual rods inside.

[0012] In one embodiment, one or more items may include a replacement stencil, a replacement support tool, a replacement and / or replacement squeegee blade, and a replacement and / or replacement paste cartridge.

[0013] In one embodiment, the conveying system may further include a conveying arm configured to push or retrieve items into or out of a translationally movable conveying section.

[0014] In one embodiment, one or more items may include a tool tray having a flat body and a frame having a size similar to the frame of a stencil.

[0015] In one embodiment, the tool tray may include at least one incision and at least one recess formed internally to support one or more foams.

[0016] Another aspect of the present disclosure relates to a stencil printer for printing assembly material on an electronic substrate. In one embodiment, the stencil printer comprises a frame and a stencil coupled to the frame, and the stencil has a hole formed therein. The stencil printer further comprises a support assembly coupled to the frame, and the support assembly comprises a tool configured to support the electronic substrate at a printing position below the stencil. The stencil printer further comprises a print head assembly coupled to the frame in a manner configured to traverse the stencil during a printing stroke. The print head assembly comprises a squeegee blade assembly for applying solder paste onto the stencil and at least one paste cartridge. The stencil printer further comprises an end effector configured to pick up and release an item from a tool tray.

[0017] In one embodiment, the end effector may be configured to pick up and release a squeegee blade assembly from a tool tray. The tool tray may include a spring-loaded locking mechanism for securing the squeegee blade holder of the squeegee blade assembly to the end effector. The end effector may include a rectangular body secured to the squeegee blade holder of the print head assembly by a pair of connecting rods. The end effector may further include a pair of downward extension pins, each pin having a notch. The squeegee blade holder may include an L-shaped recess formed internally, the recess having a vertical portion and a horizontal portion. The squeegee blade holder may include a spring-loaded pin received inside the horizontal portion of the recess, which is deflected toward the vertical portion of the recess by a spring. When the pin of the end effector is moved into the vertical portion of the recess, the inclined portion of the pin aligns with the corresponding inclined portion of the spring-loaded pin, so that the notch of the pin accommodates the aligning element of the spring-loaded pin, thereby causing the spring-loaded pin to move against the deflection of the spring until the squeegee blade holder of the squeegee blade assembly aligns with and is fixed to the end effector. The tool tray may further include an element that moves the spring-loaded pin from the aligning position to the unaligning position. The element may include an inclined portion, which aligns with a corresponding inclined portion formed on the spring-loaded pin to move the spring-loaded pin against the deflection of the spring until the squeegee blade assembly is released from the end effector by removing the aligning element of the spring-loaded pin from the notch of the pin.

[0018] In one embodiment, the stencil printer may further include a movable cart configured to interface with the stencil printer to transport items for switching and / or replacement within the stencil printer. The transport system may include a cart frame and a translationally movable transport unit comprising one or more support structures configured to support one or more items. The translationally movable transport unit is coupled to the cart frame and can move vertically relative to the frame, and the translationally movable transport unit is configured to transport one or more items to the stencil printer at a desired height.

[0019] In one embodiment, a movable cart may be configured to support a replacement paste cartridge. The stencil printer may further include a block having a recess configured to support each paste cartridge in an upright vertical position, and a movable support arm coupled to a frame, wherein the movable support arm is configured to support the block and move between a retracted position that stores the paste cartridge and an extended position that receives the paste cartridge from the movable cart. The end effector may include a paste cartridge mechanism having a support bracket configured to perform receiving, seating, sealing, and pressurizing of the paste cartridge to a print head assembly. The support bracket may include a base having a receiving feature designed to receive the bottom portion of the paste cartridge. The receiving feature may include two spaced-apart branches formed to a size that surrounds the narrow cylindrical portion of the paste cartridge, and the narrow cylindrical portion is positioned between two wider cylindrical portions to capture the branches between them. The support bracket of the paste cartridge mechanism may additionally include an upright member having a sealing portion configured to fix and seal the upper portion of the paste cartridge and to deliver compressed air to the paste cartridge to dispense solder paste.

[0020] In one embodiment, the end effector may include a support tool moving mechanism configured to move a support tool from a tool tray to a stencil printer. The support tool moving mechanism may include a plate mounted on a print head assembly. The plate may have four linear bearings, with a first set of linear bearings positioned vertically above and below each other on one side of the plate and a second set of linear bearings positioned vertically above and below each other on the other side of the plate. The support tool moving mechanism may further include a tool member configured to move laterally on the linear bearings. Each tool member may include a downward extension pin having a head configured to be received within a receiving feature associated with the support tool. The tool member may extend with a width wider than the support tool and be configured to move toward each other to capture the support tool between the pins while the pins are received in their respective receiving features.

[0021] In one embodiment, the housing is configured to have an interface designed to dock inside a docking station provided on a stencil printer.

[0022] In one embodiment, the stencil printer may further include a control unit, and the control unit is configured to control the operation of a movable cart based on operating parameters obtained from the control unit.

[0023] Another aspect of the present disclosure relates to a method for fully automating a switching and / or replacement process within a stencil printer. In one embodiment, the method comprises the steps of: identifying an item scheduled for replacement within the stencil printer; delivering one of a plurality of items to the stencil printer; removing the used item scheduled for replacement using an end effect that picks up and releases the item into and out of a tool tray; and installing the item among the plurality of items into the stencil printer.

[0024] In one embodiment, the item used is a consumed or partially consumed paste cartridge, and among the plurality of items, the item is a newly filled paste cartridge, and the end effector is configured to remove the consumed or partially consumed cartridge and install a new paste cartridge.

[0025] In one embodiment, the item used is a used squeegee blade, and among the plurality of items, the corresponding item is a new, clean squeegee blade assembly, and the end effector is configured to remove the used squeegee blade and install the new squeegee blade assembly.

[0026] In one embodiment, the item used is a tool used, and among the multiple items, the item is a new tool, and the end effector is configured to remove the tool used and install a new tool.

[0027] In one embodiment, the item used is a used stencil, and among the plurality of items, the corresponding item is a new stencil.

[0028] Another aspect of the present disclosure relates to a stencil printer for printing assembly material on an electronic substrate. In one embodiment, the stencil printer comprises a frame, a stencil coupled to the frame and having a hole formed therein, and a support assembly coupled to the frame. The support assembly comprises a tool configured to support the electronic substrate at a printing position below the stencil. The stencil printer further comprises a print head assembly coupled to the frame in a manner configured to traverse the stencil during a printing stroke. The print head assembly comprises a squeegee blade assembly for applying solder paste onto the stencil and at least one paste cartridge. The stencil printer further comprises an end effector configured to pick up and release an item from a tool tray.

[0029] An embodiment of the stencil printer may further comprise an end effector that picks up and releases a squeegee blade assembly from a tool tray. The tool tray may include a spring-loaded locking mechanism for securing the squeegee blade holder of the squeegee blade assembly to the end effector. The end effector may include a rectangular body secured to the squeegee blade holder of the print head assembly by a pair of connecting rods. The end effector may further include a pair of downward extension pins, each pin having a notch. The squeegee blade holder may include an L-shaped recess formed internally, the recess having a vertical portion and a horizontal portion. The squeegee blade holder may include a spring-loaded pin received inside the horizontal portion of the recess, which is deflected toward the vertical portion of the recess by a spring. When the pin of the end effector is moved into the vertical portion of the recess, the inclined portion of the pin aligns with the corresponding inclined portion of the spring-loaded pin, so that the notch of the pin accommodates the aligning element of the spring-loaded pin, and the spring-loaded pin moves against the deflection of the spring until this aligning element aligns with the squeegee blade holder of the squeegee blade assembly and is fixed to the end effector. The tool tray may further include an element that moves the spring-loaded pin from the aligning position to the unaligning position. The element may include an inclined portion, which is configured to align with a corresponding inclined portion formed on the spring-loaded pin to move the spring-loaded pin against the deflection of the spring until the squeegee blade assembly is released from the end effector by removing the aligning element of the spring-loaded pin from the notch of the pin.

[0030] The stencil printer may further include a movable cart configured to interface with the stencil printer to transport conversion and / or replacement items within the stencil printer. The movable cart may include a cart frame and a translational movable transport unit comprising one or more support structures configured to support one or more items. The translational movable transport unit may be coupled to the cart frame to move perpendicularly relative to the cart frame. The translational movable transport unit may be configured to deliver one or more items to the stencil printer at a desired height. The movable cart may be configured to support replacement paste cartridges. The stencil printer may include a block having a recess configured to support each paste cartridge in an upright collection position and a movable support arm coupled to the frame. The movable support arm may be configured to support the block and move between a retraction position that stores the paste cartridge and an extension position that receives the paste cartridge from the movable cart. The end effector may include a paste cartridge mechanism having a support bracket configured to receive, seat, seal, and pressurize a paste cartridge for a print head assembly. The support bracket may include a base having a receiving feature designed to receive the bottom portion of the paste cartridge. The receiving feature may include two spaced-apart branches formed to surround the narrow cylindrical portion of the paste cartridge, and the narrow cylindrical portion is positioned between two wider cylindrical portions to capture the branches between them. The support bracket of the paste cartridge mechanism may further include an upright member having a sealing portion configured to secure and seal the upper portion of the paste cartridge and to deliver compressed air to the paste cartridge to dispense solder paste.The end effector may include a support tool moving mechanism configured to move a support tool from a tool tray to a stencil printer. The support tool moving mechanism may include a plate mounted on a print head assembly, the plate having four linear bearings, a first set of linear bearings positioned vertically above and below each other on one side of the plate, and a second set of linear bearings positioned vertically above and below each other on the other side of the plate. The support tool moving mechanism may further include a tool member configured to move laterally on the linear bearings. Each tool member may include a downward extension pin having a head configured to be received within a receiving feature associated with the support tool. The tool member may extend with a width wider than the support tool and be configured to move toward each other to capture the support tool between the pins while the pins are received in their respective receiving features. The cart housing may be configured to have an interface designed to dock within a docking station provided on the stencil printer. The cart housing of the movable cart may include at least one pin accommodated within a guide associated with the stencil printer to register the movable cart to the stencil printer before it is fully docked with the movable cart. The stencil printer may further include a control unit, which is configured to control the operation of the movable cart based on operating parameters obtained from the control unit. The stencil printer may further include a display operably coupled to the control unit, which is configured to display the operating parameters of the movable cart. The control unit may be configured to access a database provided to continuously track items stored on the movable cart. The database may include an open application (app) architecture and may be configured to push data to the stencil printer.A movable cart may be configured to communicate with a stencil printer and / or directly with a production line to push / pull data to the stencil printer and / or the production line. A database may be configured to retrieve information about an item based on identification. A database may be configured to store additional information about an item, and / or share predictive data in case replacement and / or replenishment is required, and / or store data associated with the lot traceability of the data. Brief explanation of the drawing

[0031] The attached drawings are not required to be drawn in proportion to size. In the drawings, identical or nearly identical components depicted in various drawings are indicated by the same reference numeral. For clarity, not all components in all drawings may be labeled. FIG. 1 is a front view of a stencil printer; FIG. 2 is a front perspective view of a stencil printer; FIG. 3 is a top plan view of the stencil printer shown in FIG. 2 with a portion removed; FIG. 4 is a perspective view of a removable cart of one embodiment of the present disclosure, with the outer packaging removed to reveal the internal structure of the movable cart; FIG. 5a is a perspective view of a tool tray of one embodiment of the present disclosure; FIG. 5b is a perspective view of a tool tray supporting a squeegee blade assembly and a tool; FIG. 6 is a perspective view of a tool tray of another embodiment of the present disclosure; FIGS. 7A and FIGS. 7B are cross-sectional views of a part of the end effector of a print head assembly and a part of the squeegee blade holder of a squeegee blade assembly in a separated position and a aligned position, respectively; FIG. 7c is a cross-sectional view of an end effector and a squeegee blade holder in a matching position; FIGS. 8A and 8B are cross-sectional views of a release mechanism configured to release an end effector from a squeegee blade holder; FIGS. 9a and FIGS. 9b are perspective views of a magazine configured to support a paste cartridge in a retracted position and an extended position, respectively; FIG. 10 is a perspective view of a paste cartridge; FIGS. 11a to 11c are sequential drawings illustrating the installation of a paste cartridge on a print head assembly; FIG. 12 is a perspective view of a paste cartridge provided in a paste cartridge apparatus; FIGS. 13a to 13c are perspective views of a print head assembly configured to remove a tool from a tool tray. Specific details for implementing the invention

[0032] The present disclosure generally relates to a material dispensing machine (referred to herein as a “stensil printer,” “screen printer,” “printing machine,” or “printer”) and other equipment used in a surface mount technology (SMT) process line and configured to apply assembly materials (e.g., solder paste, conductive ink, or encapsulation materials) onto a substrate (e.g., a printed circuit board, referred herein 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 the present disclosure are described below with reference to a stensil printer used to produce printed circuit boards.

[0033] Without limiting generality, and solely for illustrative purposes, the present disclosure will now be described in detail with reference to the accompanying drawings. The use of the present disclosure is not limited to the details of the configuration and arrangement of the components presented in the description below or illustrated in the drawings. The principles described in the present disclosure may be implemented or performed in various ways, and other embodiments are possible. Furthermore, the grammar and terminology used herein are for illustrative purposes only and should not be construed as restrictive. Any reference to an example, embodiment, component, element, or act of a system or method referred to in the singular herein may also encompass an embodiment including a plural, and any plural reference to any embodiment, component, element, or act of the present disclosure may also encompass an embodiment including only a singular. References in the singular or plural form are not intended to limit the system or method, its components, acts, or elements currently disclosed. In this document, the use of “including,” “comprising,” “having,” “containing,” “involving,” and variations thereof means to encompass additional items as well as the items and their equivalents listed below. References to “or” may be interpreted as inclusive, so that any term described using “or” may indicate one, more than one, or all of the terms described. Furthermore, in the event of any inconsistency in the use of terms between this document and the documents cited herein by reference, the use of terms in the cited references complements the use in this document; in the event of an incompatible discrepancy, the use of terms in this document prevails.

[0034] For the sake of example, embodiments of the present disclosure will now be described with reference to a stencil printer used to print assembly materials, such as solder paste, onto a circuit board. However, those skilled in the art will understand that embodiments of the present disclosure are not limited to a stencil printer that prints solder paste onto a circuit board, but may be used for other applications requiring the dispensing of other viscous assembly materials, such as adhesives and encapsulating agents. For example, the device may be used to print epoxy for use as an underfill for chip-scale packages. Furthermore, the stencil printer according to the embodiments of the present disclosure is not limited to a printer that prints assembly materials onto a circuit board, but includes a printer used to print other materials onto various substrates, such as semiconductor wafers. Additionally, the terms screen and stencil may be used interchangeably herein to describe a device of a printer that defines a pattern to be printed on a substrate. In certain embodiments, the stencil printer may include a Momentum® or Edison™ series stencil printer platform provided by ITW Electronic Assembly Equipment, located in Hopkinton, Massachusetts. An exemplary stencil printer is collectively designated as 5 in FIG. 1. In this embodiment, the stencil printer (5) is a Momentum® series stencil printer platform provided by ITW Electronic Assembly Equipment, located in Hopkinton, Massachusetts.

[0035] Referring to FIG. 2, a stencil printer of one embodiment of the present disclosure is generally denoted as 10. As illustrated, the stencil printer (10) includes a frame (12) that supports the components of the stencil printer. The components of the stencil printer may include, in part, a control unit (14), a display (16), a stencil (18), and a print head or print head assembly, generally denoted as 20, configured to apply solder paste in a manner described in more detail below.

[0036] As illustrated in FIG. 2 and described below, the stencil and the print head assembly may be appropriately coupled to the frame (12) or otherwise connected. 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) allows the print head assembly (20) to move in the y-axis direction under the control of the control unit (14) and allows pressure to be applied to the print head assembly as the print head assembly aligns with the stencil (18). In a specific embodiment, the print head assembly (20) may be positioned over the stencil (18) and may be lowered in the z-axis direction to make contact with the stencil and align it in a sealed manner.

[0037] The stencil printer (10) may also include a conveyor system having rails (not shown) for transporting a printed circuit board (referred herein as “printed wiring board”, “substrate”, or “electronic substrate”) to a printing position of the stencil printer. The rails may be referred to herein as a “tractor feed mechanism,” and the tractor feed mechanism is configured to feed, load, or otherwise transport the circuit board to a working area of ​​the stencil printer, which may be referred herein as a “print nest,” and to unload the circuit board from the print nest.

[0038] Additionally, referring to FIG. 3, the stencil printer (10) is provided with a support assembly (28) for supporting a circuit board (29) (shown by a dotted line), the support assembly raises the circuit board and secures the circuit board so that the circuit board is stable during the printing operation. In a specific embodiment, the board support assembly (28) may further include a specific board support system, e.g., a solid support, a plurality of pins, or a flexible tool, which is positioned under the circuit board when the circuit board is in the printing position. The board support system may also be partially used to support an internal area of ​​the circuit board to prevent bending or warping of the circuit board during the printing operation.

[0039] In one embodiment, the print head assembly (20) may be configured to receive solder paste from a source, such as a solder paste cartridge, which supplies solder paste to the print head assembly during printing operation. Instead of a cartridge, other methods for supplying solder paste may be employed. For example, solder paste may be placed between blades or passively from an external source. Additionally, in a specific embodiment, the control unit (14) may be configured to use a personal computer equipped with a suitable operating system, such as the Microsoft Windows® operating system provided by Microsoft Corporation, along with application-specific software for controlling the operation of the stencil printer (10). The control unit (14) may also be networked with a master control unit used to control a production line for manufacturing circuit boards.

[0040] In one configuration, the stencil printer (10) operates as follows: A circuit board (29) is loaded onto the stencil printer (10) using a conveyor rail. A support assembly (28) raises and secures the circuit board (29) to a 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 the 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) places solder paste through the hole in the stencil (18) and onto the circuit board (29). Once the print head assembly has completely traversed the stencil (18) across the hole, 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 from the stencil printer (10) and transported so that the 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 to come into contact with the stencil and is moved across the stencil (18) in the opposite direction to the direction used for the first circuit board.

[0041] An imaging system (30) may be provided for the purpose of aligning the stencil (18) with the circuit board (29) before printing and for inspecting the circuit board after printing. In one embodiment, the imaging system (30) may be positioned between the stencil (18) and the support assembly (28) on which the circuit board is supported. The imaging system (30) is coupled to an imaging gantry (32) for moving the imaging system. In one embodiment, the imaging gantry (32) may be coupled to a frame (12) and includes a beam extending between the side rails of the frame (12) to allow the imaging system (30) to move back and forth over the circuit board (29) in the y-axis direction. The imaging gantry (32) may further include a transport device configured to accommodate the imaging system (30) and move along the length of the beam in the x-axis direction. The configuration of the imaging gantry (32) used to move the imaging system (30) is well known in the solder paste printing industry. According to this arrangement, the imaging system (30) may be positioned at any location below the stencil (18) and above the circuit board (29) to capture images of predefined areas of the circuit board or the stencil, respectively.

[0042] After applying solder paste to the circuit board one or more times, excess solder paste may accumulate on the bottom of the stencil (18), and a stencil wiper assembly, indicated by 34 overall, may move under the stencil to remove the excess solder paste. In another embodiment, the stencil (18) may move over the stencil wiper assembly.

[0043] As mentioned above, stencil printers require manual intervention to perform replacement and / or replenishment operations on specific parts. For example, a typical stencil must be replaced after a certain period of time, e.g., 4 hours. Additionally, it is necessary to replace the stencil for a separate production run. Furthermore, the solder paste cartridge that supplies temperature-controlled solder paste to the stencil printer must be replaced, for example, after a period of less than 4 hours. A separate production run may require a different solder paste material. Another item requiring periodic replacement is the squeegee blade, which may wear out during use. Finally, the tool used to support the substrate at the printing position may be replaced when changing from one production product to another.

[0044] A system and method for replacing a tool used to support a substrate at a printing position comprises the steps of retrieving a new tool from a tool storage room for a new production run or due to a defect detected in an existing tool, and transferring the new tool to one of several stencil printers. On the production line, the used tool is removed from the stencil printer, and a new tool is inserted into the stencil printer and secured for use. The used tool is transferred to a station, where the tool is inspected and, if recoverable, cleaned for reuse. If there is a defect, the tool is reliably disposed of. Once cleaned, the tool is transferred back to the tool storage room, where the tool is prepared for use during the same or a different production run.

[0045] A system and method for replacing a squeegee blade or a pair of squeegee blades comprises the steps of retrieving a new squeegee blade from a squeegee blade storage room for a new production run or due to a defect detected in an existing squeegee blade, and transferring the new squeegee blade to one of several stencil printers. On the production line, the used squeegee blade is removed from the stencil printer, and a new squeegee blade is inserted into the stencil printer and secured for use. The used squeegee blade is transferred to a station, where the squeegee blade is inspected and, if recoverable, cleaned for reuse. If a defect is found, the squeegee blade is reliably disposed of. Once cleaned, the squeegee blade is transferred back to the squeegee blade storage room, where the squeegee blade is prepared for use during the same or different production runs.

[0046] A system and method for replacing a paste cartridge for a new production run or due to the depletion of an existing paste cartridge includes the step of retrieving a new paste cartridge from a paste cartridge storage room and transferring the new paste cartridge to one of several stencil printers. The stencil printer may be part of a single production line used to manufacture printed circuit boards or may be part of multiple production lines. The number of stencil printers may vary. The storage of paste cartridges in the storage room and the transfer of paste cartridges must occur in a temperature and / or climate-controlled environment suitable for preserving the solder paste contained within the solder paste cartridges. In the production line, a "consumed" or used paste cartridge is removed from the stencil printer, and a "filled" or new paste cartridge is inserted into the stencil printer and secured for use. The consumed paste cartridge is transferred to a station, where the paste cartridge is stored (since it has not been fully used) or stored for recycling. Once stored or recycled, the paste cartridge is transferred back to the paste cartridge storage room, where the paste cartridge is prepared for use during the same or different production run.

[0047] The embodiments of the present disclosure relate to a transport system configured to automate a switching process for a stencil printer and to implement one or more of the systems and methods described herein. In one embodiment, the transport system includes a movable cart configured to be aligned with the 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 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 a replacement support tool, a replacement squeegee blade, a replenishment squeegee blade, a replacement solder paste cartridge, and a replenishment solder paste cartridge. For example, during switching, the stencil printer must be reconfigured to produce different items. Accordingly, a new support tool for receiving different substrates, a new blade having a different length, and a different type of solder paste may be employed inside the stencil printer to produce different products.

[0048] The conversion process described herein can be achieved by a single movable cart configured to replace and / or replenish each item. In other embodiments, more than one movable cart may be provided.

[0049] The above-mentioned movable cart or another movable cart is configured to support a predetermined number of tools used to support a printed circuit board at a printing location, selected for a production run expected during a specific date or period. The movable cart and / or stencil printer may be configured to identify the support tools, store the support tools, transfer the support tools to and from the stencil printer, inspect the support tools, and interface with the stencil printer. The movable cart may also be configured to remove used parts, such as support tools, from the stencil printer.

[0050] The above-mentioned movable cart or other movable cart is configured to support a predetermined number of squeegee blades selected for a production run expected on a specific date or during a specific period. The movable cart and / or stencil printer may be configured to identify the squeegee blades, store the squeegee blades, transfer the squeegee blades to and from the stencil printer, inspect the squeegee blades, and interface with the stencil printer. The movable cart may also be configured to remove used parts, such as squeegee blades, from the stencil printer.

[0051] The above-mentioned movable cart or other movable cart is configured to support a predetermined number of paste cartridges selected for production runs expected during a specific date or period. The movable cart and / or stencil printer may be configured to identify the paste cartridges, store the paste cartridges in a suitable environment, transfer the paste cartridges to and from the stencil printer, inspect the paste cartridges, and interface with the stencil printer. The movable cart may also be configured to remove used parts, such as paste cartridges, from the stencil printer. Furthermore, the movable cart may be configured to store the paste cartridges for an extended period. In one embodiment, long-term storage of the solder paste may be achieved by cooling at 0°C to 10°C (32°F to 50°F). The paste cartridges may be stored at a location within the movable cart to maintain this temperature range. In another embodiment, the movable cart may be configured to preheat the paste cartridges before use to prepare the cartridges for use in the stencil printer.

[0052] Referring to FIG. 4, in one embodiment, a movable cart, denoted as 40 in its entirety, comprises a frame or housing (42) configured to support replacement and / or supplementary items. As illustrated, the frame (42) is generally rectangular and is supported on wheels or casters (not illustrated). In one embodiment, the movable cart (40) is configured to be moved manually by an operator by pushing the frame (42) of the movable cart. In this embodiment, the movable cart (40) may be configured to have a push bar or handle. In another embodiment, the movable cart (40) is configured to be moved automatically by remote control or by an automated control unit associated with the movable cart, the stencil printer (10), the production line, and / or some other dedicated control unit. In this embodiment, the movable cart (40) may include wheels driven by a suitable motor and drive train, and a control unit associated with the movable cart, the stencil printer (10), the production line, and / or some other dedicated control unit is configured to control the movable cart. A movable cart (40) may additionally include one or more sensors and / or vision systems, such as a camera, to guide the movable cart, for example, from a storage room to a stencil printer.

[0053] A movable cart (40) includes a translational transport unit, collectively denoted as 44, which may be configured to support one or more items such as a replacement stencil, a replacement support tool, a replacement and / or replacement squeegee blade, and a replacement and / or replacement paste cartridge. The translational transport unit (44) includes a rectangular structure (46) having an upper (48), a lower (50), opposing sides (52, 54), an open front, and an open rear. The sides (52, 54) of the structure (46) may each include a slot, collectively denoted as 56, and each slot is configured to receive and support an opposing edge of a flat item such as a stencil (18), or a tool tray, collectively denoted as 60 in the illustrated embodiment. The structure (46) may be configured to receive multiple items, for example, 10 or more. The space between the slots (56) may be formed to a size for receiving a standard stencil frame inside.

[0054] A translationally movable transport unit (44) additionally includes four vertically oriented rods, each labeled 62, located at the four corners of the structure (46). As illustrated, the upper part of the structure (46) includes two bar members (64, 66), one bar member (64) is fixed to the upper part (48) of the structure adjacent to the open front of the structure, and the other bar member (66) is fixed to the upper part adjacent to the open rear. Similarly, the lower part of the structure (46) includes two bar members (64a, 66a), one bar member (64a) is fixed to the lower part (50) of the structure adjacent to the open front of the structure, and the other bar member (66a) is fixed to the lower part adjacent to the open rear. Each bar member (64, 64a and 66, 66a) includes two openings formed at opposite ends of the bar, and the openings are positioned to accommodate individual rods inside. According to this arrangement, the structure (46) can move vertically relative to the load (62) to raise and lower the structure. A suitable mechanism may be provided to raise and lower the structure (46) under the control of the control unit. For example, a ball screw drive assembly may be provided to move the structure (46) to position a “shelf” defined by a slot (56) adjacent to the stencil printer (10). The “shelf” may be specifically designed to support a tool tray (60) which may be configured to support items including, but not limited to, new and used support tools, new and used squeegee blades, and new and consumed / used paste cartridges. Some shelves may include a tool tray (60) designated as a “clean shelf” to support clean or new items ready for use inside the stencil printer (10).Some shelves may include tool trays (60) designated as "dirty shelves" to support used items to be taken from the stencil printer (10). As mentioned above, the spaces between the slots (56) may be spaced apart from each other at a specific distance to accommodate various items. For example, the shelves may be spaced 3 / 8 inch to 1½ inches apart from each other to accommodate the thickness of the stencil frame and tool tray.

[0055] A movable cart (40) may be configured to have one or more devices used to transfer items from the movable cart to the stencil printer (10) and from the stencil printer to the movable cart. For example, the device may include a transfer arm (68) configured to push the stencil (18) and the tool tray (60) into the movable cart (40) and retrieve them from the movable cart (40), respectively. For example, as shown in FIG. 4, the transfer arm (68) pushes the tool tray (60) away from the movable cart (40) and positions the tool tray to be received by the stencil printer. Any suitable mechanism, such as a ball screw drive assembly, may be provided to move the transfer arm.

[0056] Referring to FIGS. 5a and 5b, the tool tray (60) comprises a rectangular or square frame (70) and a flat body (72). The frame (70) may be formed to a size that replicates the frame of the stencil (18). In one embodiment, the tool tray (60) may be manufactured from a lightweight yet strong material, such as an aluminum alloy. As shown in FIG. 5a, the body (72) of the tool tray (60) may include several cutouts, each labeled 74, and several recesses, each labeled 76, to accommodate a support tool and a squeegee blade assembly, respectively. As shown in FIG. 5b, the cutouts (74) are configured to accommodate and secure a support tool, each labeled 78, which is provided to support the electronic substrate (29) during the stencil printing operation. The concave portion (76) is configured to receive and secure the squeegee blade assembly, each marked 80, which is used by the print head assembly (20) to perform stencil printing operations.

[0057] As noted, the tool tray (60) has substantially the same shape factor as the stencil to allow for handling and storage / retrieval of the tool tray in substantially the same manner as the stencil. The movable cart (40) and the tool tray (60) are particularly suitable for handling the stencil and the tool tray in a general manner. The movable cart (40) is configured to partially transport the tool tray (60) from the movable cart to the stencil printer (10), and the stencil printer is configured to receive the tool tray for the remainder of the time. For example, a transfer arm (68) can be used to push the tool tray (60) away from the transport unit (44) and retrieve the tool tray to the transport unit.

[0058] In some embodiments, the tool tray (60) may include a reference point that can be observed by the imaging system (30) of the stencil printer (10) to establish alignment of parts and positions on the tool tray. An alignment method for the tool tray (60) may be employed by photographing and analyzing the reference point position.

[0059] Referring to FIG. 6, the print head assembly (20) of the stencil printer (10) includes an end effector (82) that can be configured to pick up and release an item from a tool tray (60). As previously described, 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 a control unit (14). The print head assembly (20) is configured to move in the z-axis direction as previously described.

[0060] In one embodiment, the end effector (82) may be configured to lift and release the squeegee blade assembly (80). The end effector (82) is configured to align and separate the squeegee blade assembly (80) without a tool for attaching and removing the squeegee blade assembly from the print head assembly (20). As illustrated, the tool tray (60) is configured to have a spring-loaded locking mechanism for securing the squeegee blade holder of the squeegee blade assembly (80) to the end effector (82) of the print head assembly (20). A method for manually lifting and dropping the squeegee blade assembly (80) without requiring an additional axis or actuator may be performed by the end effector (82).

[0061] Referring to FIGS. 7a through 7c, the end effector (82) includes a rectangular body (84) that is secured to the print head assembly (20) by a pair of connecting rods, each labeled 86. The end effector (82) further includes a pair of downward extension pins (Fig. 7C), each labeled 88, and each pin has a notch (90) for which its use will be described as the description of the mechanism progresses. The squeegee blade assembly (80) includes a holder (92) having an L-shaped recess (94) formed inside. The recess (94) includes a vertical portion (94a) and a horizontal portion (94b). The mechanism includes a spring-loaded pin (96) that is received inside the horizontal portion (94b) of the recess (94), which is deflected toward the vertical portion (94a) of the recess by a spring (98).

[0062] FIGS. 7A and 7B illustrate a pin (88) of an end effector (82) that enters the vertical portion (94a) of a recess (94). As the pin (88) enters the vertical portion (94a) of the recess (94), the inclined portion of the pin aligns with the corresponding inclined portion of a spring-loaded pin (96). Due to the downward movement of the pin (88), the spring-loaded pin (96) moves against the deflection of the spring (98) until the notch (90) of the pin accommodates the aligning element (100) of the spring-loaded pin and aligns with the holder (92) of the squeegee blade assembly (80) to secure it to the end effector (82). FIG. 7C illustrates two pins (88) that are secured by individual spring-loaded pins (96) to secure the holder (92) of the squeegee blade assembly (80). In this position, the end effector (82) secures the squeegee blade assembly (80) so that the squeegee blade assembly can be employed to perform a stencil printing operation.

[0063] FIGS. 8A and 8B illustrate a pin (88) of an end effector (82) that is withdrawn from the vertical portion (94a) of the recess (94). An upward protruding element (102) is provided on the tool tray (60) to move the spring-loaded pin (96) from the matching position shown in FIGS. 7B and 7C to the separation position shown in FIG. 7A. Referring to FIG. 8A, the inclined portion of the element (102) aligns with the corresponding inclined portion formed on the spring-loaded pin (96). As the end effector (82) moves downward toward the element (102), the spring-loaded pin (96) is moved against the deflection of the spring (98) until the matching element (100) of the spring-loaded pin is removed from the notch (90) of the pin (88) and the squeegee blade assembly (80) is released from the end effector (82) shown in FIG. 8B. The element (102) maintains a spring-loaded pin (96) in a separated position, thereby allowing the holder (92) of the squeegee blade assembly (80) to be released.

[0064] In some embodiments, the end effector (82) may employ a magnet to align with the magnetic material associated with the squeegee blade assembly (80) in order to secure and release the squeegee blade assembly to the print head assembly (20).

[0065] Referring again to FIG. 4, a movable cart (40) includes a replacement paste cartridge, each labeled 110. As illustrated, the paste cartridge (110) is supported on the paste cartridge waiting area of ​​the movable cart (40), otherwise referred to as the "on-deck-circle," which allows the stencil printer (10) to continuously supply solder paste for uninterrupted operation. Referring to FIG. 9a and FIG. 9b, the frame (12) of the stencil printer (10) includes a block (114) having a recess configured to support the paste cartridge (110) in an upright vertical position when receiving the paste cartridge from the movable cart (40). The block (114) is fixed to a movable support arm (116), which is coupled to the frame (12) of the stencil printer (10) and configured to move from a retracted position to an extended position. Each paste cartridge (110) is supported by a cylindrical half-wall (118) for lateral support of the paste cartridge to help maintain the paste cartridge in a vertical position. Although the block (114) shown in FIGS. 9a and 9b is configured to support two paste cartridges (110), the block may be configured to support any number of paste cartridges.

[0066] FIG. 9a shows a block (114) and a movable support arm (116) in a retracted position where the stencil printer (10) stores a paste cartridge (110). FIG. 9b shows a block (114) and a movable support arm (116) in an extended position where the paste cartridge (110) can be transferred from a movable cart (40) to the block. Any suitable mechanism, such as a ball screw drive assembly, may be provided to move the movable support arm (116).

[0067] In some embodiments, the paste cartridge (110) may be supplied manually by hand onto the block (114) of the stencil printer (10) without a movable cart.

[0068] Referring to FIG. 10, even when a movable cart (40) is not present, a plurality of paste cartridges (110) may be provided in a magazine (112) of “N” paste cartridges that allow operation of the stencil printer (10), including paste switching(s). The number of paste cartridges (110) provided by the magazine (112) may be determined by the logistics requirements of the stencil printer (10) and a specific use case.

[0069] Referring to FIGS. 11a through 11c, a process for installing a paste cartridge (110) on a print head assembly (20) is illustrated sequentially. The print head assembly (20) includes a paste cartridge mechanism comprising a support bracket (120) configured to receive, seat, seal, and pressurize the paste cartridge (110) for the print head assembly (20). As illustrated, the support bracket (120) includes a base (122) having a receiving feature (124) designed to receive a bottom portion of the paste cartridge (110). In the illustrated example, the receiving feature (124) includes two spaced-apart branches formed to surround a narrow cylindrical portion of the paste cartridge (110). The narrow cylindrical portion is positioned between two wider cylindrical portions to capture the branches. The print head assembly (20) is configured to move to the paste cartridge (110) to secure the paste cartridge to the support bracket (120) of the paste cartridge mechanism by operating the print head assembly gantry (22).

[0070] The support bracket (120) of the paste cartridge mechanism further includes an upright member (126) configured to fix, seal, and pressurize the upper portion of the paste cartridge (110). The upright member (126) includes a sealing portion (128) designed to seal the upper portion of the paste cartridge (110). Once the paste cartridge (110) is seated in the receiving feature (124) of the base (122), the base is configured to move upward in the manner shown in FIG. 11b and FIG. 11c to seal the pneumatic connection of the paste cartridge (110) to the sealing portion (128). Once pressurized, the paste cartridge (110) is ready to perform a dispensing operation. Any suitable mechanism may be employed to move the base (122) upward and downward, respectively, to align the paste cartridge (110) with the sealing portion (128) and to separate it from the sealing portion (128). For example, a pneumatic assembly (130) may be provided to move the base (122). Another pneumatic cylinder (132) may be employed to lower the entire cylinder assembly during the dispensing operation. In one embodiment, the pneumatic cylinder (132) provides power for the up-and-down movement of the print head assembly (20) in the z-axis direction. After the paste cartridge (110) is lifted and sealed against the sealing portion (128), the paste cartridge may be pressurized when it is necessary to dispense solder paste. This assembly connection is made through the upright member (126) and the sealing portion (128).

[0071] FIG. 12 illustrates a paste cartridge (110) fixed and sealed by a paste cartridge mechanism. Thus, the paste cartridge mechanism can seat and seal the paste cartridge (110). The paste cartridge mechanism may be configured to accommodate paste cartridges or paste containers of various sizes.

[0072] In some embodiments, each paste cartridge (110) includes a one-dimensional barcode label that completely wraps around the paste cartridge, thereby allowing the barcode to be read in all orientations relative to the tube.

[0073] Referring to FIGS. 13a through 13c, a support tool moving mechanism is generally denoted as 140 and is configured to move a support tool (78) from a tool tray (60) to a stencil printer (10). As illustrated, the support tool moving mechanism (140) includes a plate (142) mounted on a print head assembly (20). The plate (142) is provided with four linear bearings, each denoted as 144, wherein a first set of linear bearings is positioned vertically above and below each other on one side of the plate and a second set of linear bearings is positioned vertically above and below each other on the other side of the plate. Each set of linear bearings (144) is provided with a tool member (146) configured to move laterally on the linear bearings. Any suitable mechanism may be employed to move the tool member (146). For example, a ball screw drive assembly may be provided to move the tool member (146) along the linear bearings. In one embodiment, the mechanism may be powered by a drive assembly that supplies power for the up-and-down movement of the print head assembly (20) in the z-axis direction. It includes a downward extension pin (148) having a head configured such that each tool member (146) is received within a receiving feature (150) associated with a support tool (78).

[0074] FIG. 13a illustrates a pin (148) of a tool member (146) that is received in an individual pair of feature portions (150) of a support tool (78). The tool member (146) may extend a wider width than the support tool (78) and may move toward each other to capture the support tool (78) between the pins through the receiving feature portions (150). The tool tray (60) may include an internally formed recess located adjacent to the support tool (78) so that the pin (148) may be positioned laterally adjacent to the receiving feature portions (150) of the support tool (78). FIG. 13b illustrates a print head assembly (20) that rises in the z-axis direction to pick up the support tool (78). A mechanism used to pick up and drop the support tool (78) may be configured to align with the support tool to secure the support tool, and may include a magnet to facilitate the attachment and detachment of the support tool from the tool member. As illustrated, an opening, e.g., a cut (74), is provided in the tool tray (60) to facilitate access to the support tool of the stencil printer (10) from the print head assembly (20) while the tool tray is in the stencil printer.

[0075] According to this arrangement, a movable cart (40) is configured to support a predetermined number of support tools (78) used to support a printed circuit board (29) at a printing position. The movable cart (40) and the stencil printer (10) interact to identify the support tools (78), store the support tools, transfer the support tools to and from the stencil printer, inspect the support tools, and interface with the stencil printer. The movable cart (40) and the stencil printer (10) also interact to remove used parts, such as the support tools (78), from the stencil printer.

[0076] In some embodiments, multiplexing the motion axes within the movable cart (40) can minimize the cost and complexity of the drive system. The drive unit may reside within the movable cart (40) or the stencil printer (10).

[0077] In some embodiments, the print head assembly (20) may pick up and place the support tool (78). The same print head assembly (20) may pick up and drop the squeegee blade assembly (80).

[0078] In some embodiments, the mechanism used to manage the support tool or plate (78), the squeegee blade assembly (80), and the paste cartridge (110) may be provided on another gantry, such as an imaging system gantry (32) or a stencil wiper assembly gantry, instead of the print head assembly gantry (22).

[0079] A movable cart (40) may be configured to have an interface designed to dock within a docking station provided on a stencil printer (10). In one embodiment, the interface of the movable cart is configured to dock within the docking station of the stencil printer (10) from both a mechanical interface and an electronic communication interface. In a specific embodiment, the movable cart may be configured to have a unique mechanical interface that pairs with the unique mechanical interface of the stencil printer (10). The unique mechanical interface may include geometric features. In another embodiment, the movable cart may be configured to have a pin that is received within a guide associated with the stencil printer (10) to register the movable cart to the stencil printer before it is fully docked with the movable cart. The pin and the guide may be interchanged with the pin provided on the stencil printer (10) and the guide provided on the movable cart. Other types of guides, such as electric / magnetic guides, vision guides, sensors, latches, etc., may be used. When a movable cart is docked inside the docking station of a stencil printer (10), it can be physically aligned with the stencil printer or separated from the stencil printer.

[0080] In some embodiments, a movable cart may be configured to clean the squeegee blade by cleaning or otherwise removing the used paste from the squeegee blade.

[0081] In some embodiments, a movable cart may be configured to change the used squeegee blade by releasing the squeegee blade from the print head (20) and placing the used squeegee blade on an open shelf of the movable cart. A new squeegee blade is taken from the movable cart and mounted on the print head (20) of the stencil printer (10).

[0082] In some embodiments, the movable cart includes a control unit configured to control the operation of the movable cart based on operation parameters obtained by the control unit. The control unit may be configured to communicate with the control unit (14) of the stencil printer (10) and / or a control unit associated with the production line. In one embodiment having multiple movable carts, a plurality of control units provided on each movable cart may be employed, in which the control units communicate with each other via a Controller Area Network (CAN) bus or other types of networks. In other embodiments, a master control unit may be provided to control the operation of the control units of the movable carts. A display operably coupled to the control unit may be provided on each movable cart. The display is configured to display operation parameters of the movable cart, such as, but not limited to, the number of clean and used stencils, the number of filled and consumed / used paste cartridges, the number of new and used squeegee blades, and / or the number of new and used tools. A suitable monitor may be provided to obtain this information. Alternatively, or in addition to the above-described embodiment, operating parameters may be displayed on a display (16) provided inside the stencil printer (10) and / or on a display associated with a production line.

[0083] In another embodiment, the movable cart may be controlled by a control unit (14) of the stencil printer (10) and / or a control unit associated with the production line. The control unit may be one or more control units dedicated to the movable cart.

[0084] In some embodiments, a device for manipulating an item for material identification on a movable cart and a scanner for scanning and identifying the item may be included. For example, in the case of a paste cartridge, the movable cart may be configured to include a pinch wheel for rotating the paste cartridge to align a code or a predetermined identification mark provided on the paste cartridge with a scanner provided on the movable cart. The system is configured to associate the material identification associated with the paste cartridge with a recipe, production time, etc., for the stencil printer (10). In one embodiment, a barcode for item identification may be implemented. For example, the barcode may include a 1D scanner for UPC codes, a 2D scanner for QRC codes, a printed label applied to the item, or a laser-etched label etched on the item. In another embodiment, an RFID system for item identification may be implemented. For example, the RFID system may include an RFID tag applied to the item and an RFID reader associated with the movable cart (40) or the stencil printer (10). When using an RFID system, a line-of-site (LOS) is not required between the reader and the item. Furthermore, there is no need to perform scanning to identify all items inside a movable cart. In other embodiments, an imaging or vision system for item identification may be implemented. The vision system may be an imaging system similar to the imaging system (30) associated with the stencil printer (10), and may be associated on the stencil printer, outside the stencil printer, or on the movable cart.

[0085] In some embodiments, a database is provided to track items stored on a movable cart. In one embodiment, the database may include an open application (app) architecture and may be configured to push data to a stencil printer (10). The movable cart (40) may be configured to communicate with the stencil printer (10) to push / pull data to the stencil printer and / or the production line, or to communicate directly with the production line. The database may contain work information or material information. The database may additionally communicate with a manufacturing execution system (MES) associated with the production line, the stencil printer (10), or both. The MES system may be configured to identify materials required for production execution. The movable cart may be configured to communicate with the MES system to coordinate the transport of items to the stencil printer (10).

[0086] The database may additionally be configured to retrieve information about items based on identification, for example, a barcode number. In one embodiment, a central management system may be provided in which a stencil printer (10) and / or a movable cart (40) is programmed to receive materials from the movable cart. The movable cart (40) is programmed to update the database to identify materials on the movable cart and to load information from a network associated with the movable cart and / or stencil printer (10) into the database associated with the movable cart and / or stencil printer (10).

[0087] Additionally, the database may be configured to store additional information, such as usage and consumption. The database may be configured to store information at a nearby or distant location, and may be configured to store data associated with one or more production runs. For example, the database may be configured to acquire and store data that includes, but is not limited to, traceability of stencils, paste cartridges, squeegee blades and tools, paste usage, cycles, etc.

[0088] The database may be configured to share predictive data when replacement / replenishment is required. For example, regarding the storage of information on paste cartridges, the database may be configured to perform one or more of the following: store information on when the paste cartridges need to be replenished; perform specific functions if the paste cartridges are low on paste; trigger an alarm and / or report that the paste cartridges are low on paste; transmit a signal to an inventory management system associated with the stencil printer (10) and / or production line; perform an analysis of consumable usage based on operating parameters, actual usage, and upstream / downstream equipment activity; predict change or maintenance (for the stencil printer and / or movable cart (40)); and show the correlation of multiple sites to predict when the paste cartridges need to be replaced. The database may be configured to share predictive data for other changeable / consumable items such as stencils, paste cartridges, squeegee blades, and tools.

[0089] The database may be configured to store data associated with lot traceability. Additionally, RFID or mechanical keying of the substrate or stencil frame is provided to ensure accurate alignment / orientation / direction / front-back / up-down when the item is inserted into the stencil printer (10). This information may be used to verify accurate orientation and / or fit before the item is transferred from the warehouse and / or before the item is installed in the stencil printer (10). This function may be performed by an inexpensive reader.

[0090] In some embodiments, the movable cart may be configured to store materials. The movable cart may be flexibly configured to accommodate where materials come and where materials go. Additionally, the movable cart may be configured to identify the location where specific materials are located on the movable cart. In certain embodiments, whether by automatic or manual transport, the location is at a distance or near on the movable cart and / or stencil printer (10). As mentioned above, the movable cart may be configured to control environmental parameters. For example, the movable cart may be configured to control the temperature of the paste contained within the paste cartridges by cooling stored paste cartridges, heating paste cartridges ready for use, and cooling paste cartridges that have been used but still contain paste. The movable cart may additionally be configured to predict when to start heating / cooling the paste cartridges based on upcoming production, track storage lifespan, and individually control each paste cartridge at an appropriate temperature and at an accurate time. In other embodiments, the movable cart may include a cartridge shooter for moving the paste cartridges. The movable cart can additionally be configured to control humidity to avoid condensation. The movable cart can additionally be configured to operate in a clean environment, for example, a standard mechanical interface (SMIF) environment.

[0091] In some embodiments, a movable cart may be configured to perform inventory management. Specifically, the movable cart may be configured to identify the location of materials, the amount of materials used, the method of using materials, and the time of using materials, associate the materials and information about the materials with a customer's inventory management system, and track the type of materials consumed per one or multiple substrates.

[0092] In some embodiments, a movable cart may be configured to organize items stored on the movable cart. As mentioned above, in one embodiment, a single movable cart may be provided to store, transfer, and transport a number of resources, including but not limited to stencils, paste cartridges, squeegee blades, and tools. In another embodiment, the movable cart may be configured to store, transfer, and transport a single resource or item to a stencil printer (10). For example, the movable cart may be configured to store a number of stencils. The movable cart may be configured to service a number of production lines. In another embodiment, the movable cart may be configured to service a single stencil printer (10).

[0093] In some embodiments, a movable cart may be configured to transfer items from the movable cart to the stencil printer (10) and from the stencil printer to the movable cart, taking into account the height difference between the movable cart and the stencil printer. The transfer may be automated or manual. In one embodiment, the movable cart may be moved or remotely controlled by an automated guided vehicle (AVG) technology associated with the movable cart. In another embodiment, the movable cart may be configured to move autonomously. In another embodiment, the movable cart may be configured to move manually. In yet another embodiment, the movable cart may be configured to move items stored on the movable cart automatically and / or manually. For example, the movable cart may be configured to move items automatically and may provide a interruption to a pre-planned activity in which items are moved manually.

[0094] In some embodiments, the timing associated with performing the transfer function of the movable cart can be programmed to account for shift changes, e.g., personnel changes, scheduled maintenance, on-demand activities, e.g., recipe changes, and predicted events (timed replacement). The timing can be programmed to meet the balance control requirements of multiple lines using one or more movable carts and to meet the real-time on-demand material supply demands of the production line.

[0095] In some embodiments, a movable cart is configured to perform inspection. For example, the movable cart may inspect items on the cart and items outside the cart, including stencils, paste cartridges, squeegee blades, and tools. In one embodiment, a vision system associated with the movable cart may be configured to acquire images of the items. Together with a control unit, the vision system may be configured to inspect cleanliness, damage, wear, and identifiable readability (e.g., if a barcode label is worn, dirty, or torn). The vision system may employ any type of 2D, 3D, or color camera.

[0096] In some embodiments, the interface and docking station may be configured to have a clamping system for holding a movable cart in place relative to the stencil printer (10). For example, a magnetic clamping system may be employed.

[0097] In some embodiments, the stencil printer (10) may be configured to have a plurality of docking stations, for example, five docking stations. The docking stations may be provided on the front of the stencil printer (10) or on the rear of the stencil printer.

[0098] A movable cart and / or stencil printer (10) may be configured to verify whether the movable cart can be docked and interfaced with the stencil printer. In one embodiment, verification may be provided to determine whether the movable cart is in the correct position and is ready to interface with the stencil printer (10). This verification process may 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 identified in close proximity. If it is incorrect, the movable cart (40) may be configured to activate an alarm and / or send a warning to the operator if there is incorrect or damaged material on the movable cart.

[0099] In some embodiments, the movable cart may be configured to have an actuating device or actuator for moving items in and out of the movable cart once the movable cart is docked to the stencil printer. An embodiment of the actuator may be implemented in the movable cart, the stencil printer (10), or both. In other embodiments, items may be manually loaded and unloaded from the movable cart.

[0100] In some embodiments, a movable cart may be configured to interface with a production line. According to this embodiment, an operator of the production line can confirm the exact location of the movable cart on the stencil printer (10) and notify the receipt of the movable cart.

[0101] In some embodiments, a movable cart may be configured to communicate with a selected machine inside the production line via a stencil printer (10), a production line, and / or an open platform. The communication system may include a wired system, a wireless system (via a common network, mesh, Bluetooth, Wi-Fi, Zigbee, WAN, Node, Li-Fi, etc.), a combination of wired and wireless systems, and an infrared (IR) system.

[0102] In some embodiments, the movable cart may be configured to have a dedicated power source. In one embodiment, the movable cart includes a battery configured to supply power to automated components provided on the movable cart, for example, a mechanism used to move a stencil in and out of the movable cart, a mechanism used to move a paste cartridge in and out of the movable cart, a mechanism used to move a squeegee blade in and out of the movable cart, and a mechanism used to move a tool in and out of the movable cart. In another embodiment, the movable cart may be configured to have an uninterruptible power source. The power may be configured to support operation while "docking" (high voltage of the stencil printer when docked, or low voltage when undocking). The power may be configured to recharge the battery for autonomous operation, for example, from the power provided by the stencil printer (10).

[0103] In some embodiments, a movable cart may be configured to function with a stencil printer (10). For example, the movable cart may be configured to provide a handshaking function with the stencil printer (10) before delivering an item, such as "Please give me stencil #1234." The movable cart and the stencil printer (10) may be configured to have a reference library for communication protocols and / or things that can be consumed. The movable cart may be configured to determine whether the movable cart has the correct item. The handshaking function may be configured to ensure the correct delivery of an item, such as "Here is stencil #1234," and / or the subsequent delivery of an item, such as "Now I have stencil #1234." In one embodiment, a mobile device may be configured to scan and identify items on the movable cart and, for example, determine whether the item is ready to be used, whether cleaning is required, etc.

[0104] In some embodiments, the movable cart may be configured to handle errors associated with handling and retrieving items on the movable cart. For example, the movable cart may be configured to detect incomplete operations by one party, incomplete delivery of items, e.g., stuck or jammed items, missing deliveries such as "I delivered stencil #1234. Do you not have it?", and manual intervention or invalidation such as "I will help you." In one embodiment, a control unit associated with the movable cart may be configured to perform electrostatic discharge control, data recovery, and / or security operations.

[0105] In some embodiments, the movable cart may be configured to have a higher level of capability. In addition to indexing all equipment to the correct height, it is necessary to pull or push all equipment toward the stencil printer gantry to which the movable cart is to be attached.

[0106] In some embodiments, the existing stencil printer gantry, rails, and print head of the stencil printer (10) may be configured to reciprocate the item in and out.

[0107] In some embodiments, the print head (20) of the stencil printer (10) may be configured to lift and reciprocate a support tool.

[0108] In some embodiments, the movable cart may be configured to have a paste cartridge indexer on the top of the movable cart to load / unload paste cartridges.

[0109] In some embodiments, a movable cart may be configured to communicate with a stencil printer (10), a production line, and a warehouse associated with the production line.

[0110] In some embodiments, the movable cart may be configured to have an electric / pneumatic interface.

[0111] In some embodiments, a movable cart may be configured to track new and used consumables, e.g., solder paste cartridges, on the movable cart, including location, temperature, and other data.

[0112] In some embodiments, a movable cart may be configured to store and supply stencils during the production run.

[0113] In some embodiments, a movable cart may be configured to verify and ensure that the squeegee blade is associated with the stencil to ensure part compatibility during transition.

[0114] In some embodiments, the squeegee blade may include a disposable blade that is a plastic molded blade.

[0115] In some embodiments, a movable cart may be configured to scan all consumables with a suitable scanning device, such as a barcode reader or an RFID reader.

[0116] In some embodiments, the movable cart may be configured to have an indexing mechanism for properly positioning consumables.

[0117] In some embodiments, the movable cart may be configured to have a bypass switch for separating the movable cart from the stencil printer (10) if there is a problem with the movable cart.

[0118] In some embodiments, the movable cart may be configured to be moved manually or by an automated guided vehicle (AGV).

[0119] In some embodiments, a movable cart may be configured to dock with and interface with a stencil printer (10).

[0120] In some embodiments, a movable cart may be configured to provide service to a plurality of stencil printers (10).

[0121] In some embodiments, the movable cart may be configured exclusively for a single consumable item, e.g., a stencil, or a number of consumable / conversion items.

[0122] In some embodiments, a movable cart may be configured to transport and provide consumables to be cleaned at a remote station.

[0123] In some embodiments, the movable cart may be configured to be recharged in a storage room associated with the warehouse.

[0124] In some embodiments, the movable cart may be configured to be climate-controlled actively or passively.

[0125] In some embodiments, the movable cart may be configured to be controlled by an application (app) capable of smartphone integration.

[0126] As used herein, "automated" or "fully automated" switching describes replacing or replenishing items without human intervention.

[0127] As used herein, "partially automated" switching describes replacing or replenishing items with some or limited human intervention.

[0128] As used herein, "transfer" or "transferring" describes moving an item from one location to another, either manually or using a machine.

[0129] As used herein, "to install" or "installing" describes the process of placing an item in a location ready for use.

[0130] As mentioned above, a movable cart can be employed to replace other items inside the stencil printer. For example, the stencil wiper assembly includes consumables, such as paper and solvent, that can be automatically replaced by the movable cart.

[0131] The concepts disclosed herein may be employed in other types of equipment used to manufacture electronic boards, including dispensers, pick-and-place machines, reflow ovens, wave soldering machines, selective soldering machines, inspection stations, and cleaning stations. For example, the concept of paste cartridge replacement may be employed in a dispenser used to dispense viscous materials. In another example, the concept of tool replacement may be employed in a pick-and-place machine and a dispenser used to mount electronic components onto an electronic board. In another example, the concept of item replacement may be used to replace solder inside a wave soldering machine and a selective soldering machine, and to clean products inside a cleaning station.

[0132] Although various aspects of at least one embodiment have been described as such, it should be understood by those skilled in the art that various changes, modifications, and improvements may readily occur. Such changes, modifications, and improvements are intended to constitute part of the present disclosure and are intended to be within the scope of the present disclosure. Accordingly, the foregoing description and drawings are merely illustrative.

Claims

Claim 1 A stencil printer for printing assembly material on an electronic board, comprising: a frame; a stencil coupled to the frame and having a hole formed therein; a support assembly coupled to the frame, comprising a tool configured to support the electronic board at a printing position below the stencil; a print head assembly coupled to the frame in a manner configured to traverse the stencil during a printing stroke, comprising a squeegee blade assembly for applying solder paste onto the stencil and at least one paste cartridge; an end effector configured to pick up and release an item and comprising a pair of downward extension pins; and a tool tray comprising an item having a spring-loaded locking mechanism, wherein the spring-loaded locking mechanism is actuated by a pair of downward extension pins of the end effector to secure the item to the end effector in a manner that allows the item to be releasedly fixed within the tool tray. Claim 2 A stencil printer according to claim 1, wherein the item is a squeegee blade assembly, and a pair of downward extension pins of an end effector are configured to pick up and release the squeegee blade assembly from a tool tray. Claim 3 In claim 2, the spring-loaded locking mechanism is provided in the squeegee blade holder of the squeegee blade assembly in a stencil printer. Claim 4 A stencil printer according to claim 3, wherein the end effector comprises a rectangular body fixed to a squeegee blade holder of a print head assembly by a pair of connecting rods. Claim 5 A stencil printer according to claim 3, wherein each pin of a pair of downward extension pins has a notch. Claim 6 A stencil printer according to claim 5, wherein the squeegee blade holder includes an L-shaped recess formed internally, and the recess has a vertical portion and a horizontal portion. Claim 7 A stencil printer according to claim 6, wherein the squeegee blade holder further comprises a spring-loaded pin that is deflected toward the vertical portion of the recess by a spring and received inside the horizontal portion of the recess. Claim 8 A stencil printer according to claim 7, wherein when the pin of the end effector is moved into the vertical portion of the concave portion, the inclined portion of the pin aligns with the corresponding inclined portion of the spring-loaded pin, and the notch of the pin accommodates the aligning element of the spring-loaded pin, so that the spring-loaded pin moves against the deflection of the spring until the squeegee blade holder of the squeegee blade assembly aligns with and is fixed to the end effector. Claim 9 A stencil printer according to claim 8, wherein the tool tray further comprises an element that moves a spring-loaded pin from a mating position to an unmatting position. Claim 10 A stencil printer according to claim 9, wherein the element comprises an inclined portion, the inclined portion being configured to align with a corresponding inclined portion formed on a spring-loaded pin to move the spring-loaded pin against the deflection of the spring until the squeegee blade assembly is released from the end effector by removing the mating element of the spring-loaded pin from the notch of the pin. Claim 11 A stencil printer according to claim 1, wherein the stencil printer further comprises a movable cart configured to interface with the stencil printer to transport items for switching and / or replacement within the stencil printer, the movable cart comprises a cart frame and a translationally movable transport unit comprising one or more support structures configured to support one or more items, the translationally movable transport unit coupled to the cart frame and moving vertically relative to the frame, and the translationally movable transport unit configured to transport one or more items to the stencil printer at a desired height. Claim 12 A stencil printer according to claim 11, wherein the movable cart is configured to support a replacement paste cartridge. Claim 13 In claim 12, the stencil printer further comprises a block having a recess configured to support each paste cartridge in an upright vertical position, and a movable support arm coupled to a frame, wherein the movable support arm is configured to support the block and move between a retraction position that stores the paste cartridge and an extension position that receives the paste cartridge from a movable cart. Claim 14 A stencil printer according to claim 13, wherein the end effector comprises a paste cartridge mechanism having a support bracket configured to receive, seat, seal, and pressurize a paste cartridge for a print head assembly. Claim 15 A stencil printer according to claim 14, wherein the support bracket comprises a base having a receiving feature designed to receive the bottom portion of a paste cartridge. Claim 16 A stencil printer according to claim 15, wherein the receiving feature comprises two spaced-apart branches formed to surround a narrow cylindrical portion of a paste cartridge, and the narrow cylindrical portion is positioned between two wider cylindrical portions to capture the branches therebetween. Claim 17 A stencil printer according to claim 16, wherein the support bracket of the paste cartridge mechanism further comprises an upright member having a sealing portion configured to fix and seal the upper portion of the paste cartridge and to deliver compressed air to the paste cartridge to dispense solder paste. Claim 18 A stencil printer according to claim 11, wherein the end effector comprises a support tool moving mechanism configured to move a support tool from a tool tray to a stencil printer. Claim 19 A stencil printer according to claim 18, wherein the support tool moving mechanism comprises a plate mounted on a print head assembly, the plate comprises four linear bearings, the first set of linear bearings being positioned vertically above and below each other on one side of the plate and the second set of linear bearings being positioned vertically above and below each other on the other side of the plate. Claim 20 A stencil printer according to claim 19, wherein the support tool moving mechanism further comprises a tool member configured to move laterally on a linear bearing. Claim 21 A stencil printer according to claim 20, wherein each tool member comprises a downward extension pin having a head configured to be received within a receiving feature portion associated with a support tool. Claim 22 A stencil printer according to claim 21, wherein the tool member extends with a wider width than the support tool and is configured to move toward each other to capture the support tool between the pins while the pins are received in each receiving feature. Claim 23 In claim 11, a stencil printer in which the cart frame is configured to have an interface designed to dock inside a docking station provided on the stencil printer. Claim 24 A stencil printer according to claim 11, wherein the cart frame comprises at least one pin received inside a guide associated with the stencil printer for registering the movable cart to the stencil printer before fully docking with the movable cart. Claim 25 In claim 11, the stencil printer further comprises a control unit, wherein the control unit is configured to control the operation of a movable cart based on operating parameters obtained from the control unit. Claim 26 A stencil printer according to claim 25, further comprising a display operably coupled to a control unit, wherein the display is configured to display operating parameters of a movable cart. Claim 27 In claim 25, a stencil printer in which the control unit is configured to access a database provided to continuously track items stored on a movable cart.

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