Component loading verification system and method

Abstract

A stencil printer for printing assembly materials on an electronic substrate includes a frame, a stencil coupled to the frame, the stencil having an aperture formed therein, a support assembly coupled to the frame, the support assembly configured to support the electronic substrate, a print head gantry coupled to the frame, and a print head assembly supported by the print head gantry in a manner such that the print head assembly is configured to traverse the stencil during a print stroke. The stencil printer further includes a verification system for determining whether an item placed within the stencil printer is properly installed within the stencil printer.

Description

[0001] Cross-references to related applications

[0002] This application relates to U.S. Patent Application Serial No. __________, filed on the same day by William A. Losiewicz, entitled “SQUEEGEE DRIPCOLLECTION SYSTEM FOR STENCIL PRINTER” (Attorney’s File No. M2010-735619(70054)), which is incorporated herein by reference in its entirety for all purposes. Background of the Invention

[0003] 1. Field of Invention

[0004] This application generally relates to stencil printing machines and related methods for printing viscous materials (e.g., solder paste) on electronic substrates (e.g., printed circuit boards (PCBs)), and more particularly to systems and methods for capturing and containing excess material that drips from a squeegee blade during operation. 2. Background Technology

[0006] In the manufacture of surface-mount printed circuit boards (PCBs), a stencil printer is used to print solder paste onto the circuit board. Typically, a circuit board with pad patterns or other conductive surfaces on which solder paste will be deposited is automatically fed into the stencil printer; and one or more holes or marks (called “reference points”) on the circuit board are used to properly align the circuit board with the stencil printer’s template or screen before the solder paste is printed onto the circuit board. In some systems, an optical alignment system implemented as an imaging system is used to align the circuit board with the template.

[0007] Once the circuit board is correctly aligned with the stencil in the printing press, it is raised onto the stencil. Solder paste is dispensed onto the stencil, and a squeegee blade (or scraper) traverses the stencil to force the solder paste through the orifices in the stencil onto the circuit board. As the scraper moves across the stencil, the solder paste tends to roll in front of the blade, which appropriately causes mixing and shearing of the solder paste to achieve the desired viscosity for filling the orifices in the screen or stencil. The solder paste is typically dispensed from a standard cassette onto the stencil. The stencil is then separated from the circuit board, and the adhesion between the circuit board and the solder paste leaves most of the material on the circuit board. The material remaining on the bottom surface of the stencil is removed during a cleaning process before printing another circuit board.

[0008] Before operating a stencil printer, all components installed or otherwise loaded within the printer must be correctly positioned. For example, during stencil printing operations, the toolboard supporting the electronic substrate must be correctly loaded into the printer without interference between the imaging system and the tool or other component. Summary of the Invention

[0009] One aspect of this disclosure relates to a stencil printing machine for printing assembly material on an electronic substrate. In one embodiment, the stencil printing machine includes: a frame; a stencil connected to the frame, the stencil having orifices formed therein; a support assembly connected to the frame, the support assembly being configured to support the electronic substrate; a printhead gantry connected to the frame; and a printhead assembly supported by the printhead gantry in such a way that the printhead assembly is configured to traverse the stencil during a printing stroke. The stencil printing machine further includes a verification system for determining whether an article placed within the stencil printing machine is correctly installed within the stencil printing machine.

[0010] Embodiments of the stencil printing machine may further include configuring the printhead gantry with an elongated beam spanning a track disposed on the frame. The elongated beam of the printhead gantry may include at least one linear support extending in a horizontal direction, and wherein the verification system further includes at least one tool member configured to move laterally on the at least one linear support. The at least one tool member may include a downwardly extending pin configured to move between a fully extended position and a retracted position. The verification system may further include a controller configured to move the at least one tool member over the article and determine whether the pin of the at least one tool member is in the retracted position. The verification system may further include at least one sensor positioned on the at least one tool member. The at least one sensor may be configured to generate a first visual signal indicating that the pin of the at least one tool member is fully extended and a second visual signal indicating that the pin of the at least one tool member is retracted. The at least one tool member may include two spaced-apart tool members, each tool member including a pin. The first tool member may be configured to move laterally on a first linear support, and the second tool member may be configured to move laterally on a second linear support. The pin of the at least one tool member may have an end configured to be received within a receiving feature associated with the article. The article may include at least one receiving feature configured to engage with the pin of the at least one tool member to engage and move the article. The at least one tool member may include two spaced-apart tool members, each tool member including a pin. A first tool member may be configured to move laterally on a first linear support, and a second tool member may be configured to move laterally on a second linear support. The at least one receiving feature may include two receiving features, one for each tool member, the first tool member and the second tool member being received in the corresponding receiving feature of the article to releasably secure the article. The article may include a tool plate having a flat bottom wall configured to mate with the tool base of the stencil printing machine. The verification system may include: at least one tool component configured to move laterally on at least one linear support of the printhead gantry, the at least one tool component including a downwardly extending pin configured to move between a fully extended position and a retracted position; and a controller configured to move the at least one tool component over the article and determine whether the pin of the at least one tool component is in the retracted position.

[0011] The verification system may further include at least one sensor positioned on the at least one tool member, the at least one sensor being configured to generate a first visual signal indicating that the pin of the at least one tool member is fully extended and a second visual signal indicating that the pin of the at least one tool member is retracted. The at least one tool member may include two spaced-apart tool members, each tool member including a pin. The first tool member may be configured to move laterally on a first linear support, and the second tool member may be configured to move laterally on a second linear support.

[0012] Another aspect of this disclosure relates to a method for verifying that an article is correctly mounted in a stencil printing machine. In one embodiment, the method includes: mounting the article in the stencil printing machine; and verifying that the article is correctly mounted in the stencil printing machine.

[0013] Embodiments of the method may further include: when verifying that the article is correctly installed within the stencil printing machine, moving at least one tool member laterally above the article on at least one linear support of the printhead gantry; and determining whether the at least one tool member engages the article. The at least one tool member may include a downwardly extending pin configured to move between a fully extended position and a retracted position. Determining whether the at least one tool member engages the article may include determining whether the pin of the at least one tool member is in the retracted position. Determining whether the pin of the at least one tool member is in the retracted position may include providing a first signal indicating that the pin of the at least one tool member is fully extended and a second signal indicating that the pin of the at least one tool member is retracted. The second signal may indicate that the article is not correctly installed. The article may include a tool plate having a flat bottom wall configured to mate with a tool base of the stencil printing machine.

[0014] Another aspect of this disclosure relates to a verification system for a stencil printing machine, the verification system including an elongated beam of a printhead gantry having at least one linear support extending in a horizontal direction. The verification system includes at least one tool member configured to move laterally on the at least one linear support. The at least one tool member may include a downwardly extending pin configured to move between a fully extended position and a retracted position. The verification system may further include a controller configured to move the at least one tool member over the article and determine whether the pin of the at least one tool member is in the retracted position. The verification system may further include at least one sensor positioned on the at least one tool member. The at least one sensor may be configured to generate a first visual signal indicating that the pin of the at least one tool member is fully extended and a second visual signal indicating that the pin of the at least one tool member is retracted.

[0015] In another embodiment, the at least one tool member may include two spaced-apart tool members, each tool member including a pin. A first tool member may be configured to move laterally on a first linear support, and a second tool member may be configured to move laterally on a second linear support. The pin of the at least one tool member may have an end configured to be received within a receiving feature associated with the article. The article may include at least one receiving feature configured to engage with the pin of the at least one tool member to engage and move the article. The at least one tool member may include two spaced-apart tool members, each tool member including a pin. The first tool member may be configured to move laterally on the first linear support, and the second tool member may be configured to move laterally on the second linear support. The at least one receiving feature may include two receiving features, one for each tool member, the first tool member and the second tool member being received in the corresponding receiving feature of the article to releasably secure the article. The article may include a tool plate having a flat bottom wall configured to mate with a tool base of the stencil printing machine. The verification system may include: at least one tool member configured to move laterally on at least one linear support of the printhead gantry, the at least one tool member including a downwardly extending pin configured to move between a fully extended position and a retracted position; and a controller configured to move the at least one tool member over the article and determine whether the pin of the at least one tool member is in the retracted position. The verification system may further include at least one sensor positioned on the at least one tool member, the at least one sensor configured to generate a first visual signal indicating that the pin of the at least one tool member is fully extended and a second visual signal indicating that the pin of the at least one tool member is retracted. The at least one tool member may include two spaced-apart tool members, each tool member including a pin. The first tool member may be configured to move laterally on a first linear support, and the second tool member may be configured to move laterally on a second linear support. Attached Figure Description

[0016] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in different figures is indicated by the same reference numerals. For clarity, not every component may be labeled in each figure. In the drawings:

[0017] Figure 1 This is a front view of a template printing press;

[0018] Figure 2 This is a front-view perspective view of a template printing machine;

[0019] Figure 3 yes Figure 2 The top view of the stencil printing press shown in the image has been partially removed.

[0020] Figure 4 This is a perspective view of a printhead assembly with tool component pins, according to an embodiment of the present disclosure.

[0021] Figure 5 This is a top plan view of the printhead assembly;

[0022] Figure 6 This is another 3D view of the printhead assembly;

[0023] Figures 7 to 11 This is a front view of the printhead assembly, showing a series of positions of the tool components used to remove the stencil from the printing press and verify its position;

[0024] Figure 12 This is a front view verifying that the tool is in the correct position;

[0025] Figure 13 This is the front view of the verification tool being in an incorrect position;

[0026] Figure 14 It is a schematic diagram of the pneumatic configuration of the tool components; and

[0027] Figure 15 This is a schematic diagram of the electrical configuration of the tool components. Detailed Implementation

[0028] This disclosure generally relates to material application machines (referred to herein as “stencil printers,” “screen printers,” “printing machines,” or “printers”) and other equipment used in surface mount technology (SMT) production lines 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 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 on the substrate. Specifically, embodiments of this disclosure are described below with reference to stencil printers used to produce printed circuit boards.

[0029] This disclosure will now be described in detail with reference to the accompanying drawings for illustrative purposes only and not for limiting its generality. This disclosure is not intended to limit its application to the details of the construction and arrangement of the components set forth in the following description or shown in the accompanying drawings. The principles set forth in this disclosure can be used in other embodiments and can be practiced or performed in various ways. Similarly, the wording and terminology used herein are for descriptive purposes and should not be considered limiting. Any reference to examples, embodiments, components, elements, or actions of systems and methods mentioned herein in the singular may also cover embodiments including multiple embodiments, and any reference to any embodiment, component, element, or action mentioned herein in the plural form may also cover embodiments including only a single embodiment. Singular or plural references are not intended to limit the systems or methods currently disclosed, their components, actions, or elements. The use of “comprising,” “including,” “having,” “containing,” “involving,” and variations thereof herein is intended to cover the items listed thereafter and their equivalents, as well as other items. References to “or” can be construed as inclusive, and any term described using “or” may refer to a single term, multiple terms, or any of all terms described. Furthermore, in the event of any inconsistency between the terminology used in this document and the documents incorporated herein by reference, the terminology used in the incorporated reference shall supplement the terminology used in this document; in the event of any conflicting inconsistency, the terminology used in this document shall prevail.

[0030] Embodiments of this disclosure will now be described with reference to a stencil printer for printing assembly materials (such as solder paste) onto a circuit board. However, those skilled in the art will understand that embodiments of this disclosure are not limited to stencil printers for printing solder paste onto circuit boards, but can be used for other applications requiring the dispensing of other viscous assembly materials such as adhesives and encapsulants. For example, the apparatus can be used to print epoxy resin as an underfill for chip-scale packaging. Further, the stencil printers according to embodiments of this disclosure are not limited to those printers for printing assembly materials on circuit boards, but include those printers for printing other materials on various substrates such as semiconductor wafers. Additionally, the terms "silk screen" and "stencil" are used interchangeably herein to describe means in a printer that define a pattern to be printed onto a substrate. In some embodiments, the stencil printer may include a device supplied by ITW Electronic Assembly Equipment, Hopkinton, Massachusetts. Or Edison TM Series of template printing machine platforms. An exemplary template printing machine in... Figure 1 The overall designation is 5. In this embodiment, the stencil printing machine 5 is supplied by ITW Electronic Assembly Equipment, Inc., Hopkinton, Massachusetts. Series of template printing machine platforms.

[0031] refer to Figure 2 The stencil printer 10, generally indicated by 10, is an embodiment of the present disclosure. As shown, the stencil printer 10 includes a frame 12 that supports the components of the stencil printer. The components of the stencil printer may partially include a controller 14, a display 16, a stencil 18, and a printhead or printhead assembly, generally indicated by 20, which is configured to apply solder paste in a manner described in more detail below.

[0032] like Figure 2 As shown and described below, the stencil and printhead assembly can be suitably coupled or otherwise connected to frame 12. In one embodiment, printhead assembly 20 can be mounted on a printhead assembly gantry (generally indicated by 22, sometimes referred to as the "printhead gantry") that can be mounted on frame 12. Printhead assembly 20 includes a printhead with doctor blades configured to move across stencil 18 during printing operations. Specifically, the printhead is configured to dispense solder paste (or another adhesive material) onto stencil 18, and the doctor blades are configured to force the solder paste through orifices formed in the stencil. Printhead gantry 22 enables printhead assembly 20 to move in the y-axis direction under the control of controller 14 and to apply pressure to the doctor blades when the doctor blades of the printhead assembly engage stencil 18. In one embodiment, printhead assembly 20 can be positioned above stencil 18 and can be lowered in the z-axis direction to contact and seal against the stencil.

[0033] The stencil printing press 10 may also include a conveyor system with tracks (not shown) for transporting printed circuit boards (sometimes referred to herein as “printed wiring boards,” “substrates,” or “electronic substrates”) to printing positions within the stencil printing press. The tracks, sometimes referred to herein as “traction feed mechanisms,” are configured to feed, load, or otherwise deliver the circuit boards to the working area of ​​the stencil printing press (which may be referred to herein as “printing nests”) and unload the circuit boards from the printing nests.

[0034] For further reference Figure 3 The stencil printing machine 10 has a support assembly 28 for supporting a circuit board 29 (shown in dashed lines). This support assembly raises and secures the circuit board, stabilizing it during printing operations. In some embodiments, the substrate support assembly 28 may further include a specific substrate support system, such as a robust support member, multiple pins, or flexible tools, located below the circuit board when it is in the printing position. The substrate support system may be used in part to support internal areas of the circuit board to prevent it from flexing or warping during printing operations.

[0035] In one embodiment, the printhead assembly 20 may be configured to receive solder paste from a source (such as a dispenser, e.g., a solder paste cassette) that supplies solder paste to the printhead assembly during the printing operation. Other methods of supplying solder paste may be used instead of a solder paste cassette. For example, solder paste may be manually deposited between the blades or deposited from an external source. Additionally, in one embodiment, the controller 14 may be configured to use a suitable operating system (such as Microsoft OS provided by Microsoft Corporation). A personal computer with an operating system, having software specifically designed for applications to control the operation of the stencil printing machine 10. The controller 14 can be networked with a main controller used to control the production line for manufacturing circuit boards.

[0036] In one configuration, the stencil printer 10 operates as follows: A circuit board 29 is loaded into the stencil printer 10 using a conveyor track. A support assembly 28 raises and secures the circuit board 29 in the printing position. The print head assembly 20 is then lowered in the z-axis direction until the blades of the print head assembly contact the stencil 18 with the desired pressure. The print head assembly 20 is then moved across the stencil 18 in the y-axis direction via the print head gantry 22. The print head assembly 20 deposits solder paste onto the circuit board 29 by passing it through orifices in the stencil 18. Once the print head assembly has completely traversed the stencil 18 across the orifices, the print head assembly is lifted off the stencil and the circuit board 29 is lowered back onto the conveyor track. The circuit board 29 is released from the stencil printer 10 and conveyed so that a second circuit board can be loaded into the stencil printer. For printing on the second circuit board 29, the print head assembly is lowered in the z-axis direction to contact the stencil and moved across the stencil 18 in the opposite direction to that used for the first circuit board.

[0037] Imaging system 30 can be configured for aligning stencil 18 with circuit board 29 before printing and for inspecting the circuit board after printing. In one embodiment, imaging system 30 may be positioned between stencil 18 and support assembly 28 on which the circuit board is supported. Imaging system 30 is coupled to imaging gantry 32 to move the imaging system. In one embodiment, imaging gantry 32 may be coupled to frame 12 and include beams extending between side rails of frame 12 to allow imaging system 30 to move back and forth on circuit board 29 in the y-axis direction. Imaging gantry 32 may further include a carriage arrangement that houses imaging system 30 and is configured to move in the x-axis direction along the length of the beam. The construction of imaging gantry 32 for moving imaging system 30 is well known in the solder paste printing industry. This arrangement allows imaging system 30 to be positioned anywhere below stencil 18 and above circuit board 29 to capture images of predefined areas of the circuit board or stencil, respectively.

[0038] After one or more applications of solder paste to the circuit board, excess solder paste may accumulate at the bottom of stencil 18, and the stencil wiper assembly (generally indicated by 34) can move below the stencil to remove the excess solder paste. In other embodiments, stencil 18 can move above the stencil wiper assembly.

[0039] refer to Figures 4 to 6 The printhead assembly 20 is mounted on the printhead gantry 22 to move in the y-axis direction under the control of the controller 14. The printhead gantry 22 includes tracks 38, 40 arranged along the frame 12 of the stencil printing machine 10. Figure 3 A long beam 36 spans the plate. Beam 36 includes a plate 42 having two sets of linear supports 44, 46 extending horizontally on the plate, with the top linear supports 44a, 44b positioned above the bottom linear supports 46a, 46b. The purpose of the linear supports 44a, 44b, 46a, 46b will be described in more detail below. Printhead assembly 20 includes a printhead 48 coupled to beam 36 of printhead gantry 22. Specifically, printhead 48 is mounted on a cassette 50, which is fixedly mounted on plate 42. Thus, printhead gantry 22 moves printhead 48 in the y-axis direction to perform the printing stroke described herein. Printhead 48 includes a doctor blade assembly, indicated by 52, for rolling solder paste along the stencil in the manner described above. In one embodiment, doctor blade assembly 52 includes two doctor blades, with an adhesive material (e.g., solder paste) disposed between the doctor blades.

[0040] Embodiments of the stencil printing machine 10 relate to systems and methods for measuring whether a tool plate or other part has been correctly loaded into the stencil printing machine without interference between sub-components of the stencil printing machine (such as imaging system 30 and tools or other parts). Specifically, the stencil printing machine 10 includes tool members configured to extend and retract in the z-axis direction, mounted on printhead 20 or printhead gantry 22 to be movable in the x-axis and y-axis directions. By moving the tool members in the x, y, and z-axis directions, the stencil printing machine 10 can be configured to detect the height of parts, including the tool plate, to determine whether these parts are correctly loaded or positioned within the stencil printing machine. The tool members may be configured with limit sensors to detect whether the tool members are fully extended or retracted. The tool members may be positioned and lowered to contact the top surface of the tool or part until the limit sensors change state. A position counter may be used to record the time it takes for the limit sensors to switch from on to off, and then compared with a calibration value determined during the initial calibration of the stencil printing machine 10. This determination informs the operator of the stencil printing machine 10 whether the tool plate is correctly placed and positioned at the correct height to prevent interference between the tool plate and other components of the stencil printing machine 10 (e.g., imaging system 30). Furthermore, the stencil printing machine 10 may be configured with an "offset" adjuster to maintain the tool component in the extended position during verification.

[0041] As described above, plate 42 is mounted on printhead gantry 22. Plate 42 includes two pairs of linear supports 44a, 44b and 46a, 46b. As shown, linear supports 44a, 46a are configured to support a first tool member generally indicated by 60, and linear supports 44b, 46b are configured to support a second tool member generally indicated by 62, wherein the tool member is configured to move laterally over its respective pair of linear supports.

[0042] Any suitable mechanism can be used to move the tool components 60, 62 laterally along the linear supports 44a, 46a and 44b, 46b, respectively. For example, in one embodiment, a ball screw drive assembly can be used to move the tool components 60, 62 along the linear supports 44a, 46a and 44b, 46b, respectively. In some embodiments, the ball screw drive assembly configured to move the tool components 60, 62 along the linear supports 44a, 46a and 44b, 46b, respectively, can also move the print head 48 up and down along the z-axis. As mentioned above, the print head 48 of the print head assembly 20 is configured to be lowered during printing operations to engage the stencil 18 and raised to disengage from the stencil when no printing operations are being performed. When lowered, the print head 48 applies pressure to the doctor blade assembly 52, causing the doctor blade assembly to engage the stencil 18 in a conventionally sealed manner.

[0043] In one embodiment, the first tool member 60 includes a first housing 64 fixed to linear supports 44a, 46a, wherein the first housing is configured to span along the linear supports in a lateral direction. The first tool member 60 further includes a first downwardly extending pin 66 disposed in a first cylinder 68, the first pin having an end configured to be received within a receiving feature of an article desired to be moved by the tool member, as will be described in more detail below.

[0044] Similarly, the second tool component 62 includes a second housing 70 fixed to linear supports 44b, 46b, wherein the second housing is configured to span along the linear supports in a lateral direction. The second tool component 62 further includes a second downwardly extending pin 72 disposed in a second cylinder 74, the second pin having an end configured to also be received within a receiving feature of the article. The first cylinder 68 and the second cylinder 74 are coupled to a controller 14 and a pneumatic source to control the independent up-and-down movement of the pins 66, 72 of the tool components 60, 62, respectively.

[0045] refer to Figures 7 to 11 Embodiments of the printhead assembly 20 further include a tool plate, generally indicated by 80, configured to be loaded onto or detached from a tool base 82 of the stencil printing press 10. The tool plate 80 is configured to support an electronic substrate during printing operations. As shown, the tool base 82 may include alignment pins, each indicated by 84, configured to align the tool plate 80 with the tool base and ensure proper placement of the tool plate on the tool base. The tool plate 80 includes openings that are positioned and configured to receive the alignment pins 84 when the tool plate is placed on the tool base 82.

[0046] The tool plate 80 has a generally rectangular structure, having a flat bottom wall 86, a short front wall, a short rear wall, and two short side walls that rest on the flat surface of the tool base 82 of the base plate support assembly 28. The openings are formed on the bottom surface of the bottom wall 86 of the tool plate 80. As shown, one side wall includes a first receiving feature 96 extending beyond the peripheral edge of the side wall. Similarly, the other side wall includes a second receiving feature 98 extending beyond the peripheral edge of the side wall. The receiving features 96 and 98 are configured to engage with pin 66 of the first tool member 60 and pin 72 of the second tool member 62, respectively, to engage and move the tool plate 80.

[0047] refer to Figure 7The ends of pins 66 and 72 of tool members 60 and 62 are received in corresponding first and second receiving features 96 and 98 of tool plate 80. Tool members 60 and 62 can be moved to a width close to the width of the first and second receiving features 96 and 98 of tool plate 80. Once positioned on the corresponding sides of the first and second receiving features 96 and 98 of tool plate 80, the ends of pins 66 and 72 of tool members 60 and 62 are fully movable within the receiving features to engage and support the tool plate. These tool members can be positioned by moving tool members 60 and 62 along linear supports 44a, 46a and 44b, 46b, respectively, to accommodate tool plates with receiving features of various spacings. Furthermore, pins 66 and 72 of tool members 60 and 62 can be lengthened or shortened to achieve an appropriate height of the pin ends relative to the first and second receiving features 96 and 98. The printhead assembly 20 is configured to move in the y-axis direction via the printhead gantry 22 to engage the tool plate 80 and move it to the appropriate position above the tool base 82.

[0048] It should be understood that the ends of the pins 66 and 72 of the tool members 60 and 62 can employ various mechanisms for engaging and moving the tool plate 80. In the illustrated embodiment, the pins 66 and 72 of the tool members 60 and 62 have ends that are respectively received in a first receiving feature 96 and a second receiving feature 98 of the tool plate 80. For example, each of the pins 66 and 72 of the tool members 60 and 62 may include a magnet to facilitate attachment and detachment of the tool plate 80 from the tool members, thereby lifting and moving the tool plate.

[0049] As discussed, tool components 60, 62 can be configured to pick up and release tool plate 80. Specifically, tool components 60, 62 are configured to engage and disengage with the first receiving feature 96 and the second receiving feature 98 of tool plate 80 without the need for tools.

[0050] refer to Figure 8 The tool plate 80 is lowered to engage and sit on the tool base 82, wherein the alignment pin 84 of the tool base ( Figure 7 The tool plate 80 is received within the opening of the tool plate. As shown, the tool plate 80 rests flat on the top surface of the tool base 82. The bottom surface of the bottom wall 86 of the tool plate 80 can be configured to mate with the top surface of the tool base 82 so that the tool plate is accurately positioned on the tool base.

[0051] refer to Figure 9 In order to remove tool components 60 and 62 from the receiving features 96 and 98 of the tool plate 80, the tool components move outward relative to the tool plate. Specifically, Figure 9The first tool component 60 shown moves to the left along the linear supports 44a, 46a away from the receiving feature 96 of the tool plate 80, causing the pin 66 to disengage from the receiving feature. Similarly, Figure 9 The second tool component 62 shown moves to the right along the linear supports 44b, 46b away from the receiving feature 98 of the tool plate 80, causing the pin 72 to leave the receiving feature.

[0052] refer to Figure 10 The printing head 20 is raised so that the ends of pins 66 and 72 of tool components 60 and 62 move upward, such that the ends are positioned along a plane just above the plane of the top surface of tool plate 80. As shown, pins 66 and 72 of tool components 60 and 62 are fully extended.

[0053] refer to Figure 11 This causes tool components 60 and 62 to move inward, so that the ends of pins 66 and 72 of the tool components are positioned just above the top surface of the tool plate 80. Specifically, Figure 11 The first tool component 60 shown moves to the right along the linear supports 44a and 46a toward the second tool component 62. Similarly, Figure 11 The second tool component 62 shown moves to the left along the linear supports 44b and 46b toward the first tool component 60. As shown, the ends of the pins 66 and 72 of the tool components 60 and 62 are positioned just above the top surface of the tool plate 80.

[0054] refer to Figure 12 The verification system determines whether the tool plate 80 is correctly positioned on the tool base. As shown, the verification system includes a first sensor 110 positioned on the first tool member 60, adjacent to the first cylinder 68. The first sensor 110 is configured to detect the position of the first tool member 60 and generate a visual signal, such as red light, when the first pin 66 of the first tool member is fully extended, and another visual signal, such as white light or no light, when the first pin of the first tool member is not fully extended. The verification system further includes a second sensor 112 positioned on the second tool member 62, adjacent to the second cylinder 74. The second sensor 112 is configured to detect the position of the second tool member 62 and generate a visual signal, such as red light, when the second pin 72 of the second tool member is fully extended, and another visual signal, such as white light or no light, when the second pin of the second tool member is not fully extended. In one embodiment, the first sensor 110 and the second sensor 112 of the verification system are coupled to a controller 14 to notify the operator of the sensor status in addition to the visual signals provided by the sensors.

[0055] In some embodiments, the verification system may generate an audible signal indicating that one of pins 66 or 72 is not fully extended. Further, a notification may be generated on the display 16 of the stencil printing machine 10.

[0056] Figure 12 The verification system indicates that the tool plate 80 is correctly positioned on the tool base. As shown, pins 66 and 72 of tool components 60 and 62 are both in the fully extended position. Therefore, the visual signals or indicators of sensors 110 and 112 indicate that pins 66 and 72 are in the fully extended position. Consequently, the operator of the stencil printing machine 10 will know that the tool plate 80 is correctly positioned on the tool base by visually inspecting the first sensor 110 and the second sensor 112 or by using the display 16 connected to the controller 14.

[0057] refer to Figure 13 The verification system is shown to indicate that the tool plate 80 is not properly positioned on the tool base 82. As shown, the first pin 66 of the first tool member 60 is shown in the fully extended position. However, the second pin 72 of the second tool member 62 is not fully extended. Therefore, the visual signal or indicator of the first sensor 110 indicates that the first pin 66 of the first tool member 60 is in the fully extended position, while the visual signal of the second sensor 112 indicates that the second pin 72 of the second tool member 62 is in the retracted position. As a result, the operator of the stencil printing machine 10 will know that the tool plate 80 is not properly positioned on the tool base 82 by visually inspecting the first sensor 110 and the second sensor 112 or by using the display 16 connected to the controller 14. The display 16 can instruct the operator to correct the positioning of the tool plate 80 before a catastrophic event occurs (such as before the imaging system 30 interferes with the tool plate).

[0058] refer to Figure 14 The diagram schematically illustrates the pneumatic control of the first tool component 60 and the second tool component 62. As shown, a first regulator 120 is provided to control the airflow to the first tool component 60 and the second tool component 62, causing the first pin 66 and the second pin 72 to move downwards and extend, respectively. A second regulator 122 is provided to control the airflow to the first tool component 60 and the second tool component 62, causing the first pin 66 and the second pin 72 to move upwards and retract, respectively. A solenoid valve 124 is provided between the second regulator 122 and the first tool component 60 and the second tool component 62 to control the airflow to the tool components, thereby retracting the pins 66 and 72. The pneumatic control of the first tool component 60 and the second tool component 62 is provided by a controller 14, which is connected to the first regulator 120, the second regulator 122, and the solenoid valve 124.

[0059] refer to Figure 15The diagram schematically illustrates the electronic control of the first tool component 60 and the second tool component 62. As shown, a controller 14 is connected to a DC power supply 130 and an AC power supply 132, which are also connected to the first tool component 60 and the second tool component 62. A CAN bus module 134 is provided to control the extension and retraction of pins 66 and 72 of the tool components 60 and 62, respectively.

[0060] Embodiments of this disclosure include a method for verifying that an article (e.g., a toolboard 80) is correctly seated or positioned within a stencil printing machine 10. In one embodiment, the method includes moving the article (e.g., the toolboard 80) from a remote location to a mounting position within the stencil printing machine 10. Once in place, the method further includes verifying that the article is correctly mounted within the stencil printing machine 10.

[0061] In one embodiment, a method for verifying whether an article is correctly positioned includes: fully extending pins 66, 72 of tool components 60, 62; moving the pins above the article; and detecting whether the pins retract within their respective tool components.

[0062] The system and related methods disclosed herein can be executed under the control of controller 14. Specifically, controller 14 can be configured to know when to move an item (e.g., toolboard 80) and when to replace the item. Although the toolboard is described herein as an object of the verification system, the verification system can be used to determine whether other items are correctly installed in the template printing machine 10.

[0063] In some embodiments, the existing stencil printing machine gantry, track, and printhead of the stencil printing machine 10 can be configured to allow articles (including toolboard 80) to move back and forth.

[0064] In some embodiments, the printhead assembly 20 of the stencil printing machine 10 can be configured to move and mount the tool plate 80.

[0065] In some embodiments, each sensor (i.e., sensors 110, 112) may be implemented as an analog position sensor configured to sense magnetic flux lines from a magnet in the cylinder bore of the tool members 60, 62. The analog position sensor may interpret its linear position and convert it into an output of analog voltage, current, or fieldbus signal type, which may be sent to the controller 14 of the stencil printer 10 to be converted into a distance measurement.

[0066] In some embodiments, each sensor (i.e., sensors 110, 112) may be implemented as a laser height sensor configured to emit a beam of light that is guided to reflect off a target (e.g., a toolboard) and received to interpret height based on the deviation of the light returning to the sensor. The laser height sensor may convert this into an output of analog voltage, current, or fieldbus signal type, which may be sent to the controller 14 of the stencil printer 10 to be converted into a distance measurement.

[0067] In some embodiments, each sensor (i.e., sensors 110, 112) may be implemented as an ultrasonic sensor configured to emit sound waves that are detected bouncing off a target (e.g., a toolboard) and received to interpret altitude based on the sensor's return sound. The ultrasonic sensor may convert this into an output of analog voltage, current, or fieldbus signal type, which may be sent to the controller 14 of the stencil printer 10 to be converted into a distance measurement.

[0068] In some embodiments, each sensor (i.e., sensors 110, 112) may be implemented as a linear analog position sensor, which is an integral slider / contact assembly. The linear analog position sensor directly detects position changes and converts these changes into a specific resistance in conjunction with voltage or current sensing circuitry. The output from the linear analog position sensor can be converted into an analog voltage, current, or fieldbus signal type output, which can be sent to the controller 14 of the stencil printer 10 to be converted into a distance measurement value.

[0069] In some embodiments, each sensor (i.e., sensors 110, 112) may be implemented as a contact probe, which may be a contact point assembly. The contact probe may be mounted to a movable z-axis assembly, and when the assembly presses against a surface (e.g., a tool plate), the contact probe makes or breaks contact. In conjunction with a voltage, current, or fieldbus-type output, the state changes of the contact probe may be converted into high or low signals, and then sent to the controller 14 of the stencil printer 10 to be converted into distance measurements when coupled to a z-axis position counter.

[0070] In some embodiments, each sensor (i.e., sensors 110, 112) can be implemented as a camera positioned to acquire an image of the top surface of the tool once positioned. This image can be compared to a training image, or the comparison can be performed in real time. The region of interest can be compared to both the acquired and training images to determine if any pixels in the image have changed their state, and this is converted to distance based on mils calibrated per pixel. Any type of camera can be used to perform this function.

[0071] As used herein, “correct positioning,” “correct placement,” and / or “correct installation” means that the article is in the correct position or location within the stencil printing press, which is determined by the controller after examining data associated with one or more images taken by the imaging system or camera. This known position is within predetermined tolerances, or is determined by the known fit between the article and the part of the stencil printing press designed to receive the article.

[0072] As used in this article, “transporting” or “in transit” describes the manual or automatic movement of items from one location to another.

[0073] As used in this article, "installing" or "installing" describes the process of placing an item in a ready-to-use location.

[0074] The concepts disclosed herein can be applied to other types of equipment used to manufacture electronic substrates, including dispensers, pick-and-place machines, reflow ovens, wave soldering machines, selective soldering machines, inspection stations, and cleaning stations. For example, the concepts for recycled materials can be used in soldering and wave soldering machines as well as cleaning stations.

[0075] Therefore, having described several aspects of at least one embodiment, it will be understood that various changes, modifications, and improvements will readily occur to those skilled in the art. Such changes, modifications, and improvements are intended to be part of and fall within the scope of this disclosure. Thus, the preceding description and figures are merely examples.

Claims

1. A stencil printing machine for printing assembly materials on an electronic substrate, the stencil printing machine comprising: frame; A template connected to the frame; A support assembly connected to the frame, the support assembly being configured to support the electronic substrate; A printing head gantry connected to the frame; A printhead assembly supported by the printhead gantry, configured to traverse the template during the printing stroke; as well as A verification system is used to determine whether an item placed inside the template printing machine is correctly installed inside the template printing machine. The printhead gantry includes an elongated beam spanning a track disposed on the frame, the elongated beam of the printhead gantry including at least one linear support extending in a horizontal direction, and the verification system includes at least one tool member configured to move laterally on the at least one linear support member.

2. The template printing machine as described in claim 1, wherein, The at least one tool component includes a downwardly extending pin configured to move between a fully extended position and a retracted position.

3. The template printing machine as described in claim 2, wherein, The verification system further includes a controller configured to move the at least one tool component over the article and determine whether the pin of the at least one tool component is in the retracted position.

4. The template printing machine as described in claim 3, wherein, The verification system further includes at least one sensor positioned on the at least one tool member, the at least one sensor being configured to generate a first visual signal indicating that the pin of the at least one tool member is fully extended and a second visual signal indicating that the pin of the at least one tool member is retracted.

5. The template printing machine as described in claim 4, wherein, The at least one tool component includes two spaced-apart tool components, namely a first tool component and a second tool component, each tool component including a pin, the first tool component being configured to move laterally on a first linear support, and the second tool component being configured to move laterally on a second linear support.

6. The template printing machine as described in claim 2, wherein, The pin of the at least one tool component has an end that is configured to be received within a receiving feature associated with the article.

7. The template printing machine as described in claim 6, wherein, The article includes at least one receiving feature configured to engage with a pin of the at least one tool member to engage and move the article.

8. The template printing machine as described in claim 7, wherein, The at least one tool component includes two spaced-apart tool components, namely a first tool component and a second tool component, each tool component including a pin, the first tool component being configured to move laterally on a first linear support, and the second tool component being configured to move laterally on a second linear support, wherein the at least one receiving feature includes two receiving features, one receiving feature for each tool component, the first tool component and the second tool component receiving in the respective receiving features of the article to releasably secure the article.

9. The template printing machine as described in claim 8, wherein, The article includes a tool plate with a flat bottom wall, the tool plate being configured to mate with the tool base of the stencil printing machine. The verification system determines whether the tool plate placed inside the template printing machine is correctly installed within the template printing machine within a predetermined tolerance or fit.

10. A method for verifying whether an article is correctly installed in a template printing machine as claimed in claim 1, the method comprising: Install the article in the template printing machine; as well as Verify that the item is correctly installed in the template printing machine.

11. The method of claim 10, wherein, Verifying that the item is correctly installed in the template printing machine includes: To move the at least one tool component laterally above the article on the at least one linear support of the printhead gantry, and Determine whether the at least one tool component engages with the article.

12. The method of claim 11, wherein, The at least one tool component includes a downwardly extending pin configured to move between a fully extended position and a retracted position.

13. The method of claim 12, wherein, Determining whether the at least one tool component engages the article includes determining whether the pin of the at least one tool component is in the retracted position.

14. The method of claim 13, wherein, Determining whether the pin of the at least one tool component is in the retracted position includes providing a first signal indicating that the pin of the at least one tool component is fully extended and a second signal indicating that the pin of the at least one tool component is retracted.

15. The method of claim 14, wherein, The second signal indicates that the item is not installed correctly.

16. The method of claim 10, wherein, The article includes a tool plate with a flat bottom wall, the tool plate being configured to mate with the tool base of the stencil printing machine. Verifying whether the item is correctly installed in the template printing machine includes verifying whether the tool plate is correctly installed in the template printing machine within a predetermined tolerance or fit.

17. A stencil printing machine for printing assembly materials on an electronic substrate, the stencil printing machine comprising: frame; A template connected to the frame; A support assembly connected to the frame, the support assembly being configured to support the electronic substrate; A printing head gantry connected to the frame; A printhead assembly supported by the printhead gantry, configured to traverse the template during the printing stroke; as well as A verification system is used to determine whether an item placed inside the template printing machine is correctly installed inside the template printing machine. The verification system includes: At least one tooling member configured to move laterally on at least one linear support of the printhead gantry, the at least one tooling member including a downwardly extending pin configured to move between a fully extended position and a retracted position, and A controller configured to move the at least one tool component above the article and determine whether the pin of the at least one tool component is in the retracted position.

18. The template printing machine as claimed in claim 17, wherein, The verification system further includes at least one sensor positioned on the at least one tool member, the at least one sensor being configured to generate a first visual signal indicating that the pin of the at least one tool member is fully extended and a second visual signal indicating that the pin of the at least one tool member is retracted.

19. The template printing machine as claimed in claim 18, wherein, The at least one tool component includes two spaced-apart tool components, namely a first tool component and a second tool component, each tool component including a pin, the first tool component being configured to move laterally on a first linear support, and the second tool component being configured to move laterally on a second linear support.

Images