Stencil printer cover

Abstract

The stencil printer includes a frame, a stencil, a support assembly, a print head, and a print head assembly. The print head assembly is supported by a print head gantry such that it is configured to traverse the stencil during the printing stroke. The support assembly supports an electronic substrate at a printing position under the stencil. The print head assembly includes a print head squeegee blade assembly configured to spread solder paste along the stencil. The stencil printer further includes a cover coupled to the frame so as to surround the operating members of the stencil printer including the stencil, the support assembly, the print head gantry, and the print head assembly. The cover includes an elongate opening formed therein and a movable door configured to selectively close the elongate opening. The elongate opening is sized to allow the stencil and / or the tool tray to pass through.

Description

Technical Field

[0001] The present application generally relates to a stencil printer for printing a viscous material, such as solder paste, onto an electronic substrate, such as a printed circuit board (PCB), and related methods, and more particularly, to a system and method for replacing components within the stencil printer.

Background Art

[0002] When manufacturing a surface mount printed circuit board, a stencil printer can be used to print solder paste onto the circuit board. Typically, a circuit board having a pattern of pads or some other conductive surface, on which the solder paste will be deposited, is automatically fed into the stencil printer, and one or more small holes or marks (known as "fiducials") on the circuit board are used to properly align the circuit board with the stencil or screen of the stencil printer before printing the solder paste onto the circuit board. In some systems, an optical alignment system embodying a vision system is used to align the circuit board with the stencil.

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

[0004] Another process in printing the circuit board involves inspecting the circuit board after the solder paste has been deposited on the surface of the circuit board. Inspecting the circuit board is important to determine if a clean electrical connection can be formed. Too much solder paste may cause a short circuit, while too little solder paste in the appropriate locations may prevent electrical contact. Generally, a vision inspection system is further utilized to provide two-dimensional or three-dimensional inspection of the solder paste on the circuit board.

[0005] Modern stencil printers require manual intervention to perform routine operations. For example, during switching, the operator has to perform many manual tasks such as changing the stencil, replacing the solder paste cartridge, replacing the squeegee blade, and replacing the support tool. In each of these tasks, the operator has to perform the task manually. For example, in most stencil printers, the operator has to unlock the stencil, remove the stencil, properly insert the replacement stencil, and lock the replacement stencil in place. The switching operation can take about 30 minutes, during which the stencil printer is not operating, resulting in the PCB manufacturing line not running.

Summary of the Invention

[0006] One aspect of the present disclosure relates to a stencil printer for printing assembly materials on an electronic substrate. In one embodiment, the stencil printer includes a frame, a stencil coupled to the frame, a support assembly coupled to the frame, a print head gantry coupled to the frame, and a print head assembly supported by the print head gantry such that the print head assembly is configured to traverse the stencil during a printing stroke. The stencil has a plurality of holes formed therein. The support assembly is configured to support the electronic substrate at a printing position below the stencil. The print head assembly includes a print head having a squeegee blade assembly configured to spread solder paste along the stencil. The stencil printer further includes a cover coupled to the frame so as to surround the operating members of the stencil printer including the stencil, the support assembly, the print head gantry, and the print head assembly. The cover includes an elongated opening formed therein and a movable door configured to selectively close the elongated opening. The elongated opening is sized to allow the stencil and / or the tool tray to pass through.

[0007] Embodiments of the stencil printer may further include a cover hingedly attached to the frame of the stencil printer, the cover being movable between a closed position and an open position. The cover may include a cover frame and at least one panel fixed to the cover frame. A movable door may be slidably coupled to the cover frame to enable movement of the movable door relative to the cover between a closed position and an open position. The movable door may include a movable door frame and at least one panel fixed to the movable door frame. The cover may include a linear slide mounted to the cover frame of the cover. The movable door may include a mounting bracket fixed to the movable door frame of the movable door. The cover may include a first linear slide fixed to the cover frame of the cover on one side of the movable door and a second linear slide fixed to the cover frame of the cover on the other side of the movable door. The movable door may include at least one first mounting bracket fixed to the movable door frame of the movable door on one side of the movable door and at least one second mounting bracket fixed to the movable door frame of the movable door on the other side of the movable door. The cover may include a pneumatic interlock assembly for fixing the position of the movable door in the closed position. The pneumatic interlock assembly may include an interlock latch provided on one of the movable door and the cover and an interlock cylinder provided on the other of the movable door and the cover. The interlock cylinder may be configured to releasably fix the interlock latch to fix the movable door in the closed position. The pneumatic interlock assembly may include a safety switch transmitter provided on one of the movable door and the cover and a safety switch receiver provided on the other of the movable door and the cover to ensure that the movable door is in the closed position prior to operating the stencil printer. The movable door may be configured to be moved by at least one lift bracket associated with (attached to) a movable cart. The movable door may be an access panel hingedly attached to the frame of the movable door. The access panel may be configured to be manually operated between an open position and a closed position.

[0008] Another aspect of the present disclosure relates to a cover for a stencil printer used to print assembly materials on an electronic substrate. In one embodiment, the cover includes a cover frame and a panel fixed to the cover frame. The cover includes an elongated opening formed therein and a movable door configured to selectively close the elongated opening. The elongated opening is sized to allow a stencil and / or tool tray to pass through.

[0009] The embodiment of the cover may further include hingedly attaching the cover to the frame of the stencil printer, and the cover is movable between a closed position and an open position. The movable door may be slidably coupled to the cover frame to enable movement of the movable door relative to the cover between a closed position and an open position. The movable door may include a movable door frame and at least one panel fixed to the movable door frame. The cover may include a linear slide mounted to the cover frame of the cover. The movable door may include a mounting bracket fixed to the movable door frame of the movable door. The cover may include a first linear slide fixed to the cover frame of the cover on one side of the movable door and a second linear slide fixed to the cover frame of the cover on the other side of the movable door. The movable door may include at least one first mounting bracket fixed to the movable door frame of the movable door on one side of the movable door and at least one second mounting bracket fixed to the movable door frame of the movable door on the other side of the movable door. The cover may include a pneumatic interlock assembly for fixing the position of the movable door in the closed position. The pneumatic interlock assembly includes an interlock latch provided on one of the movable door and the cover and an interlock cylinder provided on the other of the movable door and the cover, and the interlock cylinder is configured to releasably fix the interlock latch to fix the movable door in the closed position. The pneumatic interlock assembly according to claim 21, further comprising a safety switch transmitter provided on one of the movable door and the cover and a safety switch receiver provided on the other of the movable door and the cover, to ensure that the movable door is in the closed position prior to operating the stencil printer. The movable door may be configured to be moved by at least one lift bracket associated with the movable cart. The movable door may include an access panel hingedly attached to the frame of the movable door. The access panel may be configured to be manually operated between an open position and a closed position.

[0010] Yet another aspect of the present disclosure relates to a method of passing (providing) a stencil or component within a stencil printer. In one embodiment, the method includes inserting the stencil and / or tool tray into an elongated opening provided in a cover of the stencil printer.

[0011] An embodiment of the method may further include moving a movable door configured to close the elongated opening using a lift bracket of a movable cart. The method may further include manually moving an access panel of the movable door to an open position so as to enable insertion of the stencil and / or tool tray into the elongated opening.

[0012] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or substantially identical component shown in various figures is represented by like reference numerals. For clarity, not all components may be labeled in all drawings.

Brief Description of the Drawings

[0013]

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Mode for Carrying Out the Invention

[0014] The present disclosure comprehensively relates to a material coating machine (referred to herein as a "stencil printer", "screen printer", "printer", or "printing machine") and other equipment that is used in a surface mount technology (SMT) process line and is configured to apply an assembly material (e.g., solder paste, conductive ink, or encapsulation material) onto a substrate (e.g., referred to 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 stencil printer used to fabricate printed circuit boards.

[0015] For purposes of illustration only, and not to limit generality, the present disclosure will now be described in detail with reference to the accompanying drawings. The present disclosure is not limited to the details of the configurations and arrangements of components set forth in the following description or shown in the drawings with respect to its application forms. The principles described in the present disclosure can be used in other embodiments and can be practiced or carried out in various ways. Also, the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. Any reference to an example, embodiment, component, element, or operation of a system and method referred to herein in the singular includes embodiments that include a plurality thereof, and any reference to a plurality of any embodiment, component, element, or operation herein can include embodiments that include only a single one thereof. References in the singular or plural forms are not intended to limit the systems or methods, their components, operations, or elements disclosed herein. The use of the terms “including,” “comprising,” “having,” “containing,” “accompanied by,” and variations thereof herein means including the item(s) listed before, equivalents thereof, and additional item(s). References to “or / alternatively” can be construed as inclusive such that any term described using “or / alternatively” can indicate any one, more than one, and all of the terms so described. Additionally, where the usage of terms is not consistent between this specification and documents that form a part hereof by reference, the usage of terms in the documents forming a part hereof is supplementary to the usage in this specification, and where the non - consistency results in a contradiction, the usage of terms in this specification is valid.

[0016] For purposes of illustration, embodiments of the present disclosure will be described below with reference to a stencil printer used to print an assembly material, such as solder paste, onto a circuit board. However, those skilled in the art will understand that the embodiments of the present disclosure are not limited to a stencil printer that prints solder paste onto a circuit board, but can be used in other applications that require the dispensing of other adhesive assembly materials, such as glue and encapsulation materials. For example, the apparatus can be used to print an epoxy used as an underfill for a chip scale package. Further, the stencil printers of the embodiments of the present disclosure are not limited to those that print an assembly material onto a circuit board, but include those used to print other materials onto various substrates, such as semiconductor wafers. Also, the terms screen and stencil can be used interchangeably in this specification to describe devices within a printer that define a pattern to be printed on a substrate. In certain embodiments, the stencil printer can include a Momentum™ or Edison™ series stencil printer platform provided by ITW Electronic Assembly Equipment of Hopkinton, Massachusetts. An exemplary stencil printer is generally designated by 5 in FIG. 1. In this embodiment, the stencil printer 5 is a Momentum™ series stencil printer platform provided by ITW Electronic Assembly Equipment of Hopkinton, Massachusetts.

[0017] Referring to FIG. 2, a stencil printer of an embodiment of the present disclosure is generally indicated at 10. As shown, the stencil printer 10 has a frame 12 that supports the components of the stencil printer. The components of the stencil printer can include, among other things, a controller 14, a display 16, a stencil 18, and a print head or print head assembly. The print head or print head assembly is generally indicated at 20 and is configured to apply solder paste in a manner described in more detail below.

[0018] As shown in FIG. 2 and as described below, the stencil and the print head assembly can be connected to the frame 12 as appropriate or otherwise connected. In one embodiment, the print head assembly 20 can be mounted on a print head assembly gantry 22, and the print head assembly gantry 22 can be mounted on the frame 12. By the print head assembly gantry 22, the print head assembly 20 can be moved in the y-axis direction under the control of the controller 14 and can apply pressure to the print head assembly by engaging the stencil 18. In certain embodiments, the print head assembly 20 can be placed above the stencil 18 and can descend in the z-axis direction to contact and sealingly engage the stencil.

[0019] The stencil printer 10 can also have a conveyor system having rails (not shown) for transporting a printed circuit board (which may be referred to herein as a "printed wiring board", "substrate", or "electronic substrate") to a printing position within the stencil printer. The rails may be referred to herein as a "tractor feed mechanism". The tractor feed mechanism is configured to feed, load, or otherwise deliver a circuit board to a working area of the stencil printer, which may be referred to herein as a "print nest", and to unload the circuit board from the print nest.

[0020] Referring additionally to FIG. 3, the stencil printer 10 has a support assembly 28 that supports a circuit board 29 (shown in dashed lines). The support assembly 28 raises and fixes the circuit board so that the circuit board is stable during the printing operation. In certain embodiments, the substrate support assembly 28 can further include a specific substrate support system, such as a rigid support, a plurality of pins, or a flexible tool, etc., and the substrate support system is positioned below the circuit board when the circuit board is in the printing position. The substrate support system can be partially used to support the internal region of the circuit board to prevent bending or warping of the circuit board during the printing operation.

[0021] In one embodiment, the print head assembly 20 can be configured to receive solder paste from a source, such as a dispenser, for example, a solder paste cartridge, that provides the solder paste to the print head assembly during the printing operation. Instead of a cartridge, other methods of supplying the solder paste may be utilized. For example, the solder paste can be manually deposited between the blades or from an external source. Additionally, in certain embodiments, the controller 14 can be configured to use a personal computer having a suitable operating system, such as the Microsoft Windows® operating system provided by Microsoft Corporation, and use application-specific software to control the operation of the stencil printer 10. The controller 14 can be network-connected to a master controller used to control a production line for manufacturing circuit boards.

[0022] In one configuration, the stencil printer 10 operates as follows. The circuit board 29 is carried into the stencil printer 10 using a conveyor rail. The support assembly 28 raises and fixes the circuit board 29 to the printing position. Then, the print head assembly 20 is lowered in the z-axis direction until the blade of the print head assembly contacts the stencil 18 with a desired pressure. Then, the print head assembly 20 is moved in the y-axis direction across the stencil 18 by the print head assembly gantry 22. The print head assembly 20 deposits solder paste onto the circuit board 29 through a plurality of holes in the stencil 18. When the print head assembly completely traverses the stencil 18 across the holes, the print head assembly is lifted from the stencil and the circuit board 29 is lowered back onto the conveyor rail. The circuit board 29 is released and conveyed from the stencil printer 10, whereby a second circuit board can be carried into the stencil printer. To print on the second circuit board 29, the print head assembly is lowered in the z-axis direction to contact the stencil and is moved across the stencil 18 in a direction opposite to that used for the first circuit board.

[0023] An imaging system 30 can be provided for the purpose of aligning the stencil 18 with the circuit board 29 before printing and inspecting the circuit board after printing. In one embodiment, the imaging system 30 can be disposed between the stencil 18 and the support assembly 28 on which the circuit board is supported. The imaging system 30 is connected to an imaging gantry 32 for moving the imaging system. In one embodiment, the imaging gantry 32 can be connected to the frame 12, has a beam extending between the side rails of the frame 12, and provides a forward and backward movement to the imaging system 30 above the circuit board 29 in the y-axis direction. The imaging gantry 32 can further have a carriage device for accommodating the imaging system 30 and is configured to move along the length of the beam in the x-axis direction. The structure of the imaging gantry 32 used for moving the imaging system 30 is known in the art of solder paste printing. The imaging system 30 can be positioned at any position below the stencil 18 and above the circuit board 29 such that images of predetermined regions of the circuit board or the stencil can be taken respectively.

[0024] After the solder paste has been applied to the circuit board one or more times, excess solder paste can accumulate at the bottom of the stencil 18, and a stencil wiper assembly generally indicated at 34 can move below the stencil to remove the excess solder paste. In other embodiments, the stencil 18 can move above the stencil wiper assembly.

[0025] As described above, the stencil printer requires manual intervention to perform the replacement and / or replenishment operations of certain components. For example, a typical stencil needs to be replaced after a certain period, e.g., after 4 hours. Also, the stencil needs to be replaced for separate production runs. In addition, the solder paste cartridge that supplies the temperature-controlled solder paste to the stencil printer needs to be replaced over time, e.g., within 4 hours. Different solder paste materials may be required for separate production runs. Another component that requires periodic replacement is the squeegee blade that wears out during use. And finally, the tool used to support the substrate at the printing position is replaced when changing from one production item to another.

[0026] In one embodiment, the method of replacing the stencil and / or components disposed on the tool tray can include that when a new stencil and / or component on the tool tray is required for a new production run or due to wear of the existing stencil, a clean stencil and / or component is provided on the movable cart. In the production line, the "dirty" or used stencil and / or component is removed from the stencil printer, and the "clean" or new stencil and / or component is inserted into the stencil printer from the movable cart and fixed for use. The dirty stencil and / or component can then be conveyed to a cleaning station that cleans the stencil and / or component in preparation for reuse. Once cleaned, the stencil and / or component can be conveyed back to the stencil printer or storage room and reused during the same or different production runs.

[0027] Embodiments of the present disclosure relate to a delivery system configured to automate the switching process for a stencil printer and to implement one or more of the methods described herein. In one embodiment, the delivery system has a movable cart configured to engage with a stencil printer and to supply and receive replacement and replenishment parts and materials to and from the stencil printer. For example, the stencil printer can have a docking station configured to receive the movable cart. The docking station can have an interface that enables the movable cart to communicate with the stencil printer. A single movable cart can be configured to have switching stencils and / or replacement stencils. During switching, for example, the stencil printer has to be reconfigured to produce different articles. Thus, a new stencil can be utilized within the stencil printer to produce different products.

[0028] The switching process described herein can be realized by a single movable cart configured to replace and / or replenish each part. In other embodiments, two or more movable carts can be provided. For example, for stencil switching, the movable cart is configured to support a predetermined number of stencils. The movable cart and / or the stencil printer can be configured to identify, store, transport to and from the stencil printer, inspect, and interface with the stencil printer. The movable cart can also be configured to remove used parts, such as stencils, from the stencil printer.

[0029] Embodiments of the present disclosure further relate to a delivery system configured to automate the replenishment process for a stencil printer. In one embodiment, the delivery system has a movable cart configured to engage with the stencil printer and supply and receive replacement and replenishment parts and materials to and from the stencil printer. For example, the stencil printer can have a docking station configured to receive the movable cart. The docking station can have an interface that enables the movable cart to communicate with the stencil printer. A single movable cart can be configured to have a switching stencil and a replacement stencil.

[0030] Referring to FIG. 4, a stencil printer, generally designated 100, is substantially identical to the stencil printer 10 described above, unless otherwise explained. The stencil printer 100 includes a cover, generally designated 102, hingedly secured to the frame of the stencil printer for movement from an open position where the interior of the stencil printer is accessible to a closed position shown where the operating members of the stencil printer described above are enclosed. In certain embodiments, the cover 102 of the stencil printer 100 is made from a metal frame 104 having panels embodying a see-through material, such as plexiglass, each generally designated 106, to enable an operator to view the working components of the stencil printer 100 during operation.

[0031] As shown, cover 102 includes an elongated slot 108 that allows components positioned in the stencil and tool tray to be inserted into and removed from stencil printer 100. Cover 102 further includes a movable door, generally designated 110, that is slidably mounted along opposite ends of the elongated slot and sized to surround the elongated slot when in the closed position. Movable door 110 is configured to move up and down relative to the cover. In one embodiment, movable door 110 includes an access panel 111 that is hingedly attached to the frame 104 of the cover and allows an operator to manually insert and remove components through the elongated slot 108.

[0032] Figure 4 shows access panel 111 of movable door 110 in the open position such that components on the tool tray, such as a stencil or squeegee blade and tools, can be inserted into and removed from the stencil printer. Specifically, when access panel 111 of movable door 110 is in the open position, elongated slot 108 functions as a mail slot that allows for a partially automated exchange of components including the stencil, squeegee blade, and tools. The operator can pass the stencil and / or tool tray through the elongated slot, and an end effector or tool loading / unloading mechanism associated with the print head of stencil printer 100 removes and returns the stencil and / or tool tray to the operator. Figure 5 shows an operator passing a component through elongated slot 108 into stencil printer 100, with access panel 111 shown in the open position.

[0033] During product exchange, the software associated with the controller of the stencil printer 100 prompts the operator to load or exchange the required part(s) and guides the operator through the process step by step. Once loaded and ready to resume production, the stencil printer 100 scans each newly added part to verify that the correct parts for the print job have been loaded prior to continuing.

[0034] FIG. 6 shows the access panel 111 of the movable door 110 shown in the closed position surrounding the working components of the stencil printer. As described in more detail below, the movable door 110 of the cover 102 may be configured to be lifted by a movable cart (described below), allowing the movable cart to interface with the stencil printer 100 such that the stencil printer can place or remove a printed circuit board (PCB) support tool, squeegee blade, and / or stencil while maintaining inaccessibility to any operator interface inside the stencil printer. FIG. 7 shows an operator standing in front of the movable door 110 with the access panel 111 and the movable door shown in the closed position.

[0035] Referring to FIGS. 8 and 9, a movable cart, generally designated 200, is shown in a docking position relative to the stencil printer 100. As will be described in more detail below, the movable cart 200 includes at the front of the movable cart a lift bracket for lifting the movable door 110 of the cover 102 of the stencil printer 100 to open the movable door. The movable cart 200 is docked to the stencil printer 100, and the lift bracket at the front of the movable cart is provided to engage the lower surface of the movable door 110 of the cover 102. The movable cart 200 is powered at this point, and the door interlock assembly associated with the movable door 110 is disabled. Based on parts being added or removed from the stencil printer 100, the controller of the stencil printer determines, for example, which shelves in the movable cart 200 will align with the stencil shelves in the stencil printer. The movable cart 200 passively lifts the movable door 110 to the required height in the z-axis direction, and when in place, the movable cart is prompted to be ready to receive one or more parts being loaded into or unloaded from the stencil printer 100. For example, when prompted to unload a stencil, the stencil is unloaded from the stencil printer 100 directly in the y-axis direction into the movable cart 200, the movable cart stores the stencil, and then indexes directly in the z-axis direction to receive the next part(s) being loaded or unloaded. The next part may be another stencil and / or a part such as a tool on the tool tray and / or a squeegee blade, or an empty tool tray.

[0036] Figure 10 shows the movable door 110 of the cover 102 of the stencil printer 100 in the maximum open position or fully open position. In this position, the elongated slot 108 can accommodate up to four shelves of the movable cart 200. Depending on the requirements for the stencil printer, the stencil and / or tool tray can be carried in or out in the y-axis direction from the stencil printer 100 to the movable cart 200, or from the movable cart to the stencil printer. The movable cart 200 may be configured to index the shelves of the movable cart in the z-axis direction to perform the next required operation until the switching sequence is complete. When completed, the movable cart 200 is configured to move the shelf supporting the stencil and / or tool tray to the home position in the y-axis direction. Next, the movable cart 200 is configured to move the shelf to the home position in the z-axis direction so that the stencil printer 100 can resume production. At this point, the movable door 110 of the cover 102 of the stencil printer 100 is interlocked for the operator's safety.

[0037] The movable cart 200 may remain docked to the stencil printer 100 or may be removed when the loading or unloading is complete.

[0038] Referring to FIGS. 11 and 12, the cover 102 of the stencil printer 100 is shown being removed from the stencil printer 100. As described and illustrated above, the cover 102 includes an L-shaped frame 104 having an end hingedly attached to the frame of the stencil printer 100 by a hinge 112. A portion of the L-shaped frame 104 has a first solid panel 106a and another portion of the L-shaped frame has a second transparent panel 106b that extends vertically when the cover 102 is in the closed position. In one embodiment, the hinge 112 is mounted at the upper rear of the frame of the stencil printer 100 and is attached to the cross member of the frame 104 of the cover 102.

[0039] Referring to FIG. 12, the movable door 110 is configured to move vertically inside the cover 102. In one embodiment, the movable door 110 includes a rectangular frame 110a having a see-through panel 110b and an access panel 111. As described above, the access panel 111 is hingedly connected to the frame 110a along the bottom end of the access panel. The cover 102 includes two linear slides, each indicated by 114, one slide being attached to the frame 104 of the cover on the left hand side inside the cover, and the other slide being attached to the frame of the cover on the right hand side inside the cover. The linear slides 114 are attached to the movable door 110 using four mounting brackets, each indicated by 116, enabling the movable door to move vertically up and down inside the cover 102. Specifically, two mounting brackets 116 are fixed to the frame 110b of the movable door on one side of the frame, and two mounting brackets are fixed to the frame of the movable door on the other side of the frame. The mounting brackets 116 are each configured to slide along the linear slide 114, allowing the up and down movement of the movable door 110 relative to the frame 104 of the cover.

[0040] Referring to FIGS. 13 and 14, the cover 102 includes a pneumatic interlock assembly for fixing the position of the movable door 110. As shown, the pneumatic interlock assembly includes an interlock latch 120 provided on the movable door 110 and an interlock cylinder 122 provided on the cover 102. The interlock cylinder 122 is configured to releasably fix the interlock latch 120 to fix the movable door 110 in the closed position. The pneumatic interlock assembly further includes a safety switch transmitter 124 provided on the movable door 110 and a safety switch receiver 126 provided on the cover 102. The safety switch transmitter 124 and the safety switch receiver 126 are provided to ensure that the movable door 110 is in the closed position prior to operating the working components of the stencil printer 100. In another embodiment, the pneumatic interlock assembly includes a safety switch provided to detect that the door 110 is in the closed position. In one example, the safety switch may be a plunger type switch.

[0041] Referring to FIGS. 15 and 16, as described above, the movable cart 200 includes two lift brackets, each indicated at 130, which are located at the front of the movable cart and are provided to engage the lower surface of the movable door 110 of the cover 102. Although provided at the front of the movable cart 200, the two lift brackets 130 may be positioned and / or disposed relative to the movable cart in any desirable manner convenient for lifting the movable door 110. When the movable cart 200 is docked to the stencil printer 100, the two lift brackets 130 are positioned to slide under the bottom lip 132 of the frame 110a of the movable door 110 shown in FIG. 16. When the movable cart 110 is initialized and begins to move the vertical shelves on the movable cart to align with the stencil shelves in the stencil printer 100, the two brackets 130 passively lift the movable door 110, thereby optionally allowing the appropriate stencil and / or tool tray to be carried into the stencil printer or carried out of the stencil printer to the movable cart.

[0042] Referring to FIGS. 17 and 18, the access panel 111 of the movable door 110 is shown open in FIG. 17 and closed in FIG. 18. Hinges 134 are provided to enable the movement of the access panel 111 of the movable door between the open and closed positions. The hinges 134 are fixed to the frame 110a of the movable door 110 and the access panel 111. Similar hinges are also provided on the opposite side of the access panel.

[0043] The operating members of the movable door 110, including the interlock latch 120 and interlock cylinder 122, and the safety switch transmitter 124 and safety switch receiver 126, are further illustrated.

[0044] Referring to FIG. 19, the operator can open and close the access panel 111 of the movable door 110 by using the handle 136 provided on the outer surface of the access panel. The manual operation of the access panel 111 of the movable door 110 can only be performed when the switching is started and the pneumatic interlock assembly is removed. When this task is executed, the access panel 111 of the movable door 110 can be opened, thereby releasing the connection with the safety switch. When the access panel 111 of the movable door 110 is opened, the stencil printer 100 becomes substantially inoperable until the safety switch is closed.

[0045] Referring to FIGS. 20 to 22, in another embodiment, the cover 150 includes an elongated slot 152 and a movable door 154 that is slidably attached to the cover and is movable between an open position (FIG. 20) and a closed position (FIG. 21). FIG. 22 shows the opposite side of the movable door 154 with the movable door in the open position. The structures of the cover 150 and the movable door 154 are similar to the assembly of the cover 102 and the movable door 110 shown and described above. The movable door 154 is configured to move up and down automatically by either the operator or the controller of the stencil printer.

[0046] As shown in FIG. 22, the movable door 154 is fixed to the cover 150 by a first set of fixing brackets fixed to the cover. One fixing bracket 156 is fixed to the cover on one side of the elongated slot 152, and the other fixing bracket 158 is fixed to the cover on the opposite side of the elongated slot. Each bracket 156, 158 of the first set of fixing brackets includes a vertically mounted cylinder 162, 164 respectively. Each cylinder 162, 164 is guided by a vertically mounted door guide or retainer 166, 168 respectively. There is a second set of brackets attached to the movable door 154 and attached to the respective cylinder shafts of the cylinders 162, 164 to drive the up and down movement of the movable door. One bracket 170 is fixed to the movable door on one side of the movable door, and the other bracket 172 is fixed to the movable door on the opposite side of the movable door.

[0047] The movable door 154 further includes a rack and pinion type damping rotary assembly 180 so that the door safely returns to the home (closed) position when the door is lifted. In other words, the movable door can move freely in the upward or open direction, and when it is moved in the downward or closed direction, the rack and pinion type damping rotary assembly 180 resists the downward movement of the movable door to prevent the movable door from closing suddenly.

[0048] To open the movable door 154, the operator (or software associated with the controller of the stencil printer) issues a command to open the movable door. In one embodiment, the operator can enter the command on a graphical user interface (GUI) associated with the display of the stencil printer. When this is done, the stencil printer will be suppressed when the safety compliance sensor / switch 174 is disconnected from the movable door 154. The movable door 154 is fixed in a closed position that closes access to the elongated slot 152 by the interlock assembly 176 and the safety compliance sensor / switch 174.

[0049] Embodiments of the present disclosure may further include a method of facilitating the automated loading and / or replacement of required process-related components in a machine when interfaced with an automated cart.

[0050] In one embodiment, changing the replaceable parts of a complete stencil printer requires removing the stencil, unloading the squeegee blade and tools from the stencil printer, followed by loading new squeegee blades and tools, and inserting a new stencil into the printer. In one example, the sequence of replacing parts in a stencil printer includes the following order. The existing stencil is removed from the stencil printer. Next, an empty tool tray is inserted into the stencil printer using the print head and print head gantry of the stencil printer. The empty tool tray may be passed by an operator or by a mobile cart. The position of the tool tray is verified by using visual alignment verification software associated with the controller. As described above, an imaging system may be employed to take an image of the empty tool tray and transmit the image to the controller for verification.

[0051] After determining the location of the tool tray, the front and rear squeegee blades are removed and placed in the tool tray. Next, the tools are picked up and placed in the tool tray by using the tool pins associated with the print head and print head gantry. When the squeegee blades and tools are placed in the tool tray, the tool tray is removed from the stencil printer.

[0052] Next, the loaded tool tray is inserted into the stencil printer using the print head and print head gantry of the stencil printer. Here too, the loaded tool tray may be passed to the stencil printer by an operator or may be passed to the stencil printer by a movable cart. Specifically, the loaded tool tray is intended to replace the used squeegee blade and used tools previously removed from the stencil printer and includes new front and rear squeegee blades and new tools. Next, the visual alignment verification software of the stencil printer associated with the controller is used to position the tool tray within the stencil printer. Similar to the positioning of an empty tool tray, an imaging system may be employed to take an image of the loaded tool tray and transmit the image to the controller for verification.

[0053] Next, the new tool is placed on the workholder table of the stencil printer, such as on the support assembly 28, by using the tool pins associated with the print head and print head gantry of the stencil printer. Next, the new front and rear squeegee blades are picked up and installed on the print head. After installing the new tool and squeegee blades, the tool tray is removed from the stencil printer. And finally, a new stencil is inserted into the stencil printer. At this point, the sequence of replacing parts in the stencil printer is completed.

[0054] In some embodiments, the print head assembly of the stencil printer, such as print head assembly 20, may include an end effector configured to pick up and release components from the tool tray. As described above, in stencil printer 10, print head assembly 20 is mounted to a print head assembly gantry 22 that moves the print head assembly in the y-axis direction under the control of controller 14. Print head assembly 20 is configured to move in the z-axis direction as described above.

[0055] In one embodiment, the end effector may be configured to pick up and release, for example, a squeegee blade. The end effector is configured to engage and disengage the squeegee blade without tools to attach and remove the squeegee blade from the print head assembly 20. In one embodiment, the tool tray may be configured with a spring-biased locking mechanism for securing the squeegee blade holder of the squeegee blade to the end effector of the print head assembly 20. A method of passively picking up and dropping off the squeegee blade without the need for additional axes or actuators may be performed by the end effector.

[0056] In one embodiment, the end effector includes a rectangular body fixed to the print head assembly by a pair of connecting rods. The end effector may further be configured with a pair of downwardly extending pins configured to releasably secure the squeegee blade. The pins may also be used to manipulate the stencil and / or tool tray by moving the stencil and / or tool tray laterally within the stencil printer.

[0057] In one embodiment, the movable cart includes a frame or housing configured to support replacement and / or replenishment items. The frame may be generally rectangular and may be supported on wheels or casters. In one embodiment, the movable cart is configured to be manually moved by an operator by pushing on the housing of the movable cart. In this embodiment, the movable cart may be configured with a push bar or handle. In another embodiment, the movable cart is configured to be automatically moved by remote control or by an automated control associated with the movable cart, the stencil printer, the production line, and / or some other dedicated control. In this embodiment, the movable cart may include wheels driven by a suitable motor and drive train, and the control associated with the movable cart, the stencil printer, the production line, and / or some other dedicated control is configured to control the movable cart. The movable cart may further include one or more sensors and / or a vision system, such as a camera, to guide the movable cart from a storage room to, for example, a stencil printer.

[0058] As discussed, the movable cart is configured with one or more shelves for storing parts for the stencil printer. For example, these shelves may be specifically designed to support new and used stencils, and / or other parts such as new and depleted / used paste cartridges, new and used squeegee blades, and new and used tools. The one or more shelves may be configured to move vertically and index within the housing to achieve a height suitable for operating with the stencil printer. Some shelves may be designated as "clean shelves" to support clean or new parts ready for use within the stencil printer.

[0059] Some shelves may be designated as "dirty shelves" to support used parts to be removed from the stencil printer. The shelves may be spaced a specific distance from each other to receive various parts. For example, these shelves may be spaced from 3 / 8 inch (about 9.5 mm) to 1+1 / 2 inches (about 38.1 mm) from each other to accommodate the thickness of the stencil frame and / or the tool tray.

[0060] Although the shelves are shown as being oriented horizontally, it should be understood that the shelves may be arranged in a vertical orientation such that the stencil is inserted into and removed from the shelf slots within a vertical plane.

[0061] The movable cart may be configured to include one or more devices used to transfer parts from the movable cart to the stencil printer 10 and from the stencil printer to the movable cart. For example, the device may include grippers or transfer arms that assist in removing and inserting parts such as stencils from the movable cart.

[0062] The movable cart may be configured to include an interface designed to dock within a docking station provided in the stencil printer. In one embodiment, the movable cart includes an interface configured to dock within the docking station of the stencil printer from both a mechanical interface and an electronic device communication interface. In a particular embodiment, the movable cart may be configured to include a unique mechanical interface that mates with the unique mechanical interface of the stencil printer. The unique mechanical interface may include geometric features. In another embodiment, the movable cart may be configured to include pins that are received within guides associated with the stencil printer to align the movable cart with the stencil printer prior to fully docking the movable cart. Other types of guides such as electrical / magnetic guides, visual guides, sensors, latches, etc. may be used. The movable cart may physically engage with the stencil printer or may be separated from the stencil printer when docked within the docking station of the stencil printer.

[0063] In some embodiments, the movable cart has a controller, and the controller is adapted to control the operation of the movable cart based on the operation parameters obtained by the controller. The controller can be configured to communicate with the controller of the stencil printer and / or the controller associated with the production line. In one embodiment having a plurality of movable carts, the controller can embody a plurality of controllers provided in each movable cart that communicate with each other via a Controller Area Network (CAN) bus or other type of network. In other embodiments, a master controller can be provided to control the operation of the controller of the movable cart. Each movable cart can be provided with a display operably coupled to the controller. The display is adapted to display the operation parameters of the movable cart, including but not limited to a clean stencil and a used stencil or the number of parts provided on the tool tray. To obtain such information, a suitable monitor can be provided. Alternatively, or in addition to the foregoing embodiments, the operation parameters may be displayed on a display provided in the stencil printer and / or a display associated with the production line.

[0064] In other embodiments, the movable cart can be controlled by the controller of the stencil printer and / or the controller associated with the production line. The controller can be a controller dedicated to one or more movable carts.

[0065] In some embodiments, the material identification for parts on a movable cart can include a device for manipulating the parts and a scanner for scanning and identifying the parts. In one embodiment, a barcode for identifying the parts can be provided. For example, the barcode can include a 1D scanner for UPC codes, a 2D scanner for QR codes, a printed label attached to the part, or a laser etching label etched on the part. In another embodiment, an RFID system for identifying the parts can be applied. For example, the RFID system can include an RFID tag attached to the part and an RFID reader associated with the movable cart. By using the RFID system, a line-of-site between the reader and the part is not required. Also, a scan for identifying all parts within the movable cart is not required. In another embodiment, an imaging or vision system for identifying the parts can be applied. The vision system can be an imaging system similar to the imaging system 30 associated with the stencil printer 10 and can be associated on the stencil printer, outside the stencil printer, or on the movable cart.

[0066] In some embodiments, a database is provided to track parts stocked on a movable cart. In one embodiment, the database can include an open application (App) architecture and can be configured to push data to the stencil printer. The movable cart can be configured to communicate with the stencil printer to push / pull data to / from the stencil printer and / or the production line, or to communicate directly with the production line. The database can include job information or material information. The database can further communicate with a manufacturing execution system (MES) associated with the production line, the stencil printer, or both. The MES system can be configured to know which materials are required for a production run. The movable cart can be configured to communicate with the MES system to adjust the delivery of parts to the stencil printer.

[0067] The database can be further configured to retrieve information about parts based on identification information, such as barcode numbers. In one embodiment, a central management system can be provided that programs a stencil printer and / or a mobile cart to receive materials coming from the mobile cart. The mobile cart is programmed to update the database to identify materials on the mobile cart and load information from the network into the database associated with the mobile cart and / or the stencil printer, and the information is further associated with the MES system.

[0068] The database can be further configured to store additional information such as usage and consumption amounts. The database can be configured to store information locally or remotely and can be configured to store data related to one or more production runs. For example, the database can be configured to acquire and store data including, but not limited to, the traceability of stencils and / or tool trays.

[0069] The database can be configured to share predictive data when an exchange / replenishment is needed. For example, with respect to storing information about stencils and / or tool trays, the database can be configured to perform one or more operations. The database can be configured to share predictive data about other changeable / consumable parts such as stencils and / or tool trays.

[0070] The database can be configured to store data related to lot traceability. Additionally, an RFID of the board or mechanical keying or a stencil frame of the stencil is provided to ensure correct alignment, orientation, direction, front-back, and top-bottom when these components are inserted into the stencil printer. This information can be used to verify the correct orientation and / or fit before the components are transported from the warehouse and / or before the components are installed in the stencil printer. This function can be performed by a low-cost reader.

[0071] In some embodiments, the movable cart can be configured to store materials. The movable cart can be configured to have flexibility to adapt to where the materials come from and where the materials go. Additionally, the movable cart can be configured to identify where a particular material is located on the movable cart. In certain embodiments, the location is remote, local, on the movable cart, and / or on the stencil printer, regardless of whether it is an automatic delivery or a manual delivery.

[0072] In some embodiments, the movable cart can be configured to perform inventory management. Specifically, the movable cart can identify where the materials are located, how much the materials are used, how the materials are used, and when the materials are used, associate the materials and information about the materials with a customer inventory management system, and be configured to track the types of materials consumed per panel or per lot of panels.

[0073] In some embodiments, the movable cart can be configured to organize the parts stored on the movable cart. As described above, in one embodiment, although not limited, one movable cart can be provided to store, transport, and deliver a plurality of resources including, but not limited to, stencils and / or tool trays. In another embodiment, the movable cart can be configured to store a single resource or part and transport and deliver it to a stencil printer. For example, the movable cart can be configured to store a plurality of stencils and / or tool trays. The movable cart can be configured to serve multiple production lines. In another embodiment, the movable cart can be configured to serve one stencil printer.

[0074] In some embodiments, the movable cart can be configured to transport parts from the movable cart to the stencil printer and from the stencil printer to the movable cart, and can be configured to take into account the height difference between the movable cart and the stencil printer in the calculation. The transportation can be automated or manual. In one embodiment, the movable cart can be moved by autonomous vehicle (AVG) technology associated with the movable cart or can be remotely controlled. In another embodiment, the movable cart can be configured to move autonomously. In another embodiment, the movable cart can be configured to be moved manually. In still other embodiments, the movable cart can be configured to automatically and / or manually move the parts stored on the movable cart. For example, the movable cart can be configured to automatically move the parts and can be prepared for an interruption of a pre-planned activity in which the parts are moved manually.

[0075] In some embodiments, the timing associated with the execution of the transport function of the mobile cart can be programmed to take into account shift changes, such as operator shifts, scheduled maintenance, on-demand activities, such as recipe changes, and precursor events (just-in-time exchanges). The timing can be programmed to meet multiple line balance control requirements using one or more mobile carts and to meet the demand for real-time on-demand material supply on the production line.

[0076] In some embodiments, the mobile cart is configured to perform inspections. For example, the mobile cart can inspect parts on and off the cart, including stencils and / or tool trays. In one embodiment, the vision system associated with the mobile cart can be configured to obtain images of the parts. The vision system, in conjunction with the controller, can be configured to inspect cleanliness, damage, wear, and identification information readability, such as whether a barcode label is worn, unclean, or torn. The vision system can embody any type of 2D, 3D, or color camera.

[0077] In some embodiments, the mobile cart is configured to interface with a stencil printer from both a mechanical interface and an electrical communication interface. In one embodiment, the mobile cart can be configured to have a unique mechanical interface that mates with the unique mechanical interface of the stencil printer. The unique mechanical interface can be a geometric feature. In another embodiment, the mobile cart can be configured to have pins that are received within a guide associated with the stencil printer to align the mobile cart with the stencil printer before fully docking the mobile cart. The pins and the guide can be reversed, with the pins provided on the stencil printer and the guide provided within the mobile cart. Other types of guides, such as electrical / magnetic guides, vision guides, sensors, latches, etc., can be used.

[0078] In some embodiments, the interface and the docking station can be configured to have a clamping system that holds the movable cart in place relative to the stencil printer. For example, a magnetic clamping system can be utilized.

[0079] In some embodiments, the stencil printer can be configured to have a plurality of docking stations, for example, five docking stations. The docking stations can be provided at the front of the stencil printer or at the rear of the stencil printer.

[0080] The movable cart and / or the stencil printer can be configured to verify whether the movable cart can dock and interface connect with the stencil printer. In one embodiment, the verification can be provided to confirm whether the movable cart is in the appropriate position and ready to interface connect with the stencil printer. This verification process can further determine whether the correct material is on the movable cart and whether the movable cart material information can be received from the MES system or identified locally. If not, the movable cart can be configured to activate an alarm and / or warn the operator if incorrect or damaged material is on the movable cart.

[0081] In some embodiments, the movable cart can be configured to have an actuating device or actuator that moves parts onto and off of the movable cart when the movable cart is docked to the stencil printer. Embodiments of the actuator can be mounted on the movable cart, the stencil printer. In another embodiment, the parts can be manually loaded and unloaded with respect to the movable cart.

[0082] In some embodiments, the movable cart can be configured to interface with the production line. According to this embodiment, an operator of the production line can confirm the correct location of the movable cart on the stencil printer and recognize its acceptance.

[0083] In some embodiments, the movable cart can be configured to communicate with a stencil printer, a production line, and / or selected machines within the production line via an open platform. The communication system can include a wired system, a wireless system (via a common network, mesh, Bluetooth®, Wi-Fi, Zigbee®, WAN, Nodes, Li-Fi, etc.), a combination of wired and wireless systems, and an infrared (IR) system.

[0084] In some embodiments, the movable cart can be configured to have a dedicated power source. In one embodiment, the movable cart has a battery configured to supply power to automated components provided within the movable cart, for example, a mechanism used to move the stencil and / or tool tray in and out of the movable cart. In other embodiments, the movable cart can be configured to have an uninterruptible power supply. The power source can be configured to support operation while "docked" (high voltage from the stencil printer when docked, low voltage when undocked). The power source can be configured to recharge for autonomous operation, for example, recharge the battery from the power provided by the stencil printer.

[0085] In some embodiments, the movable cart can be configured to function with a stencil printer. For example, the movable cart can be configured to provide a handshake function with the stencil printer 10, such as "Please give me stencil #1234", before transferring parts. The movable cart and the stencil printer can be configured to have a communication protocol and / or a library reference regarding what is consumable. The movable cart can be configured to determine whether the movable cart has the correct parts. The handshake function can be configured to ensure the correct transfer of parts, such as "Here is stencil #1234", and / or to ensure subsequent transfer of parts, such as "I have stencil #1234". In one embodiment, the mobile device can be configured to scan and identify parts within the movable cart and to determine, for example, whether the parts are ready for use, whether cleaning is required, etc.

[0086] In some embodiments, the movable cart can be configured to handle errors related to the handling and removal of parts within the movable cart. For example, the movable cart can be configured to detect incomplete actions by a party, incomplete transfer of parts, such as snagging or jamming of parts, dropping of transferred items, such as "I passed you stencil #1234, do you have it?", and manual intervention or manual override, such as "Let me help". In one embodiment, the controller associated with the movable cart can be configured to perform electrostatic discharge control, data recovery, and / or protection.

[0087] In some embodiments, the movable cart can be configured to have higher capabilities. In addition to indexing all devices to the correct height, the movable cart may need to pull in / push out all devices for attaching a machine gantry.

[0088] In some embodiments, the existing machine gantry, rails, and print heads of a stencil printer can be configured to allow for component swapping.

[0089] In some embodiments, the mobile cart can be configured to communicate with a stencil printer, a production line, and a warehouse associated with the production line.

[0090] In some embodiments, the mobile cart can be configured to have an electrical / air interface.

[0091] In some embodiments, the mobile cart can be configured to track new and used consumables on the mobile cart, such as stencils and / or tool trays, including location, temperature, and other data.

[0092] In some embodiments, the mobile cart can be configured to store and supply components on stencils and / or tool trays over the duration of a production run.

[0093] In some embodiments, the mobile cart can be configured to scan all consumables using a suitable scanning device such as a barcode reader or an RFID reader.

[0094] In some embodiments, the mobile cart can be configured to have an indexing mechanism to properly position consumables.

[0095] In some embodiments, the mobile cart can be configured to have a bypass switch to disconnect the mobile cart from the stencil printer 10 if there is a problem with the mobile cart.

[0096] In some embodiments, the mobile cart can be configured to be moved manually or by an automated guided vehicle (AGV).

[0097] In some embodiments, the movable cart can be configured to dock and interface with a stencil printer.

[0098] In some embodiments, the movable cart can be configured to serve multiple stencil printers.

[0099] In some embodiments, the movable cart can be configured to be dedicated to one consumable part, such as a stencil, or multiple consumable / switching parts.

[0100] In some embodiments, the movable cart can be configured to transport and deliver consumables to be cleaned at a remote station.

[0101] In some embodiments, the movable cart can be configured to be replenished in a storage room associated with a warehouse.

[0102] In some embodiments, the movable cart can be configured to be actively or passively environmentally controlled.

[0103] In some embodiments, the movable cart can be configured to be controlled by a smartphone-integrable application (App).

[0104] As used herein, "automated" or "fully automated" switching describes replacing or replenishing parts without human intervention.

[0105] As used herein, "partially automated" switching describes replacing or replenishing parts with some or limited human intervention.

[0106] As used herein, "transport" or "transporting" describes moving a component from one location to another, either manually or using a machine.

[0107] As used herein, "install" or "installing" describes the process of placing a component in a location where it is ready for use.

[0108] As described above, the movable cart can be used to replace other components within 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.

[0109] The concepts disclosed herein may be utilized in other types of equipment used to fabricate electronic substrates, including dispensers, pick-and-place machines, reflow ovens, wave soldering machines, selective soldering machines, inspection stations, and cleaning stations. For example, the concept related to the replacement of a paste cartridge can be utilized in a dispenser used to dispense a viscous material. In another example, the concept directed to the replacement of tools can be utilized in a dispenser and a pick-and-place machine used to attach electronic components to an electronic substrate. In another example, the concept related to the replacement of components can be utilized for the replacement of solder in wave soldering machines and selective soldering machines, and for the cleaning of products within a cleaning station.

[0110] Thus, while some aspects of at least one embodiment have been described, it is understood that various modifications, changes, and improvements will be readily apparent to those skilled in the art. Such modifications, changes, and improvements are intended to be part of this disclosure and are intended to be within the scope of this disclosure. Accordingly, the foregoing description and drawings are by way of example only.

Claims

1. A stencil printer for printing an assembly material on an electronic substrate, comprising: a frame; a stencil coupled to the frame, the stencil having a plurality of holes formed therein; a support assembly coupled to the frame and configured to support the electronic substrate at a printing position below the stencil; a print head gantry coupled to the frame; a print head assembly supported by the print head gantry such that the print head assembly is configured to traverse the stencil during a printing stroke, the print head assembly including a print head having a squeegee blade assembly configured to spread solder paste along the stencil; a cover coupled to the frame so as to surround the operating members of the stencil printer including the stencil, the support assembly, the print head gantry, and the print head assembly, the cover including an elongated opening formed therein and a movable door configured to selectively close the elongated opening, the elongated opening being sized to permit passage of the stencil and / or a tool tray.

2. The stencil printer according to claim 1, wherein the cover is hingedly attached to the frame of the stencil printer and is movable between a closed position and an open position.

3. The stencil printer according to claim 1, wherein the cover further includes a cover frame and at least one panel fixed to the cover frame.

4. The stencil printer according to claim 3, wherein the movable door is slidably coupled to the cover frame to enable movement of the movable door relative to the cover between a closed position and an open position.

5. The stencil printer according to claim 4, wherein the movable door includes a movable door frame and at least one panel fixed to the movable door frame.

6. The cover further includes a linear slide mounted on the cover frame of the cover, and the movable door further includes a mounting bracket fixed to the movable door frame of the movable door. The stencil printer according to claim 5.

7. The cover further includes a first linear slide fixed to the cover frame of the cover on one side of the movable door, and a second linear slide fixed to the cover frame of the cover on the other side of the movable door. The stencil printer according to claim 5.

8. The movable door further includes at least one first mounting bracket fixed to the movable door frame of the movable door on one side of the movable door, and at least one second mounting bracket fixed to the movable door frame of the movable door on the other side of the movable door. The stencil printer according to claim 7.

9. The cover further includes a pneumatic interlock assembly for fixing the position of the movable door in the closed position. The stencil printer according to claim 5.

10. The pneumatic interlock assembly includes an interlock latch provided on one of the movable door and the cover, and an interlock cylinder provided on the other of the movable door and the cover. The interlock cylinder is configured to releasably fix the interlock latch to fix the movable door in the closed position. The stencil printer according to claim 9.

11. The pneumatic interlock assembly includes a safety switch for ensuring that the movable door is in the closed position prior to operating the stencil printer. The stencil printer according to claim 9.

12. The movable door is configured to be moved by at least one lift bracket associated with a movable cart. The stencil printer according to claim 1.

13. The movable door includes an access panel hingedly mounted to the frame of the movable door. The access panel is configured to be manually operated between an open position and a closed position. The stencil printer according to claim 1.

14. The stencil printer according to claim 1, wherein the movable door includes an assembly configured to provide resistance to a downward movement of the movable door.

15. A cover for a stencil printer used for printing an assembly material on an electronic substrate, a cover frame, a panel fixed to the cover frame, comprising: the cover includes an elongated opening formed in the cover and a movable door configured to selectively close the elongated opening, and the elongated opening is sized to allow the stencil and / or tool tray to pass through. Cover.

16. The cover according to claim 15, wherein the cover is hingedly attached to a frame of the stencil printer and is movable between a closed position and an open position.

17. The cover according to claim 15, wherein the movable door is slidably coupled to the cover frame to enable movement of the movable door relative to the cover between a closed position and an open position.

18. The cover according to claim 17, wherein the movable door includes a movable door frame and at least one panel fixed to the movable door frame.

19. The cover according to claim 18, wherein the cover further includes a linear slide mounted to the cover frame of the cover, and the movable door further includes a mounting bracket fixed to the movable door frame of the movable door.

20. The cover according to claim 18, wherein the cover further includes a first linear slide fixed to the cover frame of the cover on one side of the movable door and a second linear slide fixed to the cover frame of the cover on the other side of the movable door.

21. The cover according to claim 20, wherein the movable door further includes at least one first mounting bracket fixed to the movable door frame of the movable door on one side of the movable door and at least one second mounting bracket fixed to the movable door frame of the movable door on the other side of the movable door.

22. The cover according to claim 18, wherein the cover further includes a pneumatic interlock assembly for fixing the position of the movable door in the closed position.

23. The pneumatic interlock assembly includes an interlock latch provided on one of the movable door and the cover, and an interlock cylinder provided on the other of the movable door and the cover, and the interlock cylinder is configured to releasably fix the interlock latch to fix the movable door in the closed position. The cover according to claim 22.

24. The cover according to claim 22, wherein the pneumatic interlock assembly includes a safety switch for ensuring that the movable door is in the closed position prior to operating the stencil printer.

25. The cover according to claim 15, wherein the movable door is configured to be moved by at least one lift bracket associated with the movable cart.

26. The cover according to claim 15, wherein the movable door includes an access panel hingedly attached to the frame of the movable door, and the access panel is configured to be manually operated between an open position and a closed position.

27. The cover according to claim 15, wherein the movable door includes an assembly configured to resist a downward movement of the movable door.

28. A method of passing a stencil or parts within a stencil printer, inserting the stencil and / or tool tray into an elongated opening provided in a cover of the stencil printer including, method.

29. The method according to claim 28, further including moving a movable door configured to close the elongated opening with a lift bracket of a movable cart.

30. The method according to claim 29, further including manually moving an access panel of the movable door to an open position so as to enable inserting the stencil and / or tool tray into the elongated opening.

Images