Squeegee drip collection system for stencil printer

A squeegee drip collection system is configured to receive assembly material from at least one squeegee blade of the print head assembly. The squeegee drip collection system includes a paste shield coupled to the print head gantry and configured to be moved between a retracted position in which the paste shield is spaced from the at least one squeegee blade and an extended position in which the paste shield is positioned under the at least one squeegee blade. The squeegee drip collection system further includes a paste shield removal assembly configured to uncouple the paste shield from the print head gantry and to remove the paste shield.

RELATED APPLICATION

This application relates to U.S. patent application Ser. No. 17/469,996 titled “COMPONENT LOADING VERIFICATION SYSTEM AND METHOD”, by Patsy A. Mattero and Steven R. Foster, filed on even date herewith, which is incorporated herein by reference in their entirety for all purposes.

BACKGROUND OF THE DISCLOSURE

1. Field of Invention

This application relates generally to stencil printers and related methods to print viscous materials, e.g., solder paste, on an electronic substrate, e.g., a printed circuit board (PCB), and more particularly to systems and methods for catching and containing excess material that drips from a squeegee blade during operation.

2. Discussion of Related Art

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

Once the circuit board has been properly aligned with the stencil in the printer, the circuit board is raised to the stencil, solder paste is dispensed onto the stencil, and a wiper blade (or squeegee) traverses the stencil to force the solder paste through apertures in the stencil and onto the circuit board. As the squeegee is moved across the stencil, the solder paste tends to roll in front of the blade, which desirably causes mixing and shearing of the solder paste so as to attain a desired viscosity to facilitate filling of the apertures in the screen or stencil. The solder paste typically is dispensed onto the stencil from a standard cartridge. The stencil is then separated from the circuit board and the adhesion between the circuit board and the solder paste causes most of the material to stay on the circuit board. Material left on a bottom surface of the stencil is removed in a cleaning process before additional circuit boards are printed.

One issue is preventing solder paste from dripping off the squeegee blades during operation and contaminating the operational workspace. During operation, solder paste can inadvertently drip off of the squeegee blades when traversing the stencil printer, falling on the stencil or the electronic substrate support.

SUMMARY OF THE DISCLOSURE

One aspect of the present disclosure is directed to a stencil printer for printing an assembly material on an electronic substrate. In one embodiment, the stencil printer comprises a frame, a stencil coupled to the frame, the stencil having apertures formed therein, and a support assembly coupled to the frame, the support assembly being configured to support the electronic substrate. The stencil printer further comprises a print head gantry coupled to the frame, a print head assembly supported by the print head gantry in such a manner that the print head assembly is configured to traverse the stencil during print strokes, and a squeegee drip collection system configured to receive assembly material from at least one squeegee blade of the print head assembly. The squeegee drip collection system includes a paste shield coupled to the print head gantry and configured to be moved between a retracted position in which the paste shield is spaced from the at least one squeegee blade and an extended position in which the paste shield is positioned under the at least one squeegee blade. The squeegee drip collection system further includes a paste shield removal assembly configured to uncouple the paste shield from the print head gantry and to remove the paste shield.

Embodiments of the stencil printer further may include the paste shield having a flat bottom wall, a front wall, a back wall and two side walls that create a shallow receptacle to receive solder paste from the at least one squeegee blade. The print head gantry may include an elongate beam that rides along rails provided on the frame. The elongate beam of the print head gantry may include at least one linear bearing that extends in a horizontal direction. The paste shield removal assembly may include at least one tooling member configured to move laterally on the at least one linear bearing. The at least one tooling member may include a downwardly extending pin having an end configured to be received within a receiving feature associated with the paste shield. The paste shield may include at least one receiving feature configured to be engaged by the pin of the at least one tooling member to engage and move the paste shield. The at least one tooling member may include two spaced-apart tooling members, each including a pin, a first tooling member being configured to move laterally on a first linear bearing and a second tooling member being configured to move laterally on a second linear bearing. The at least one receiving feature may include two receiving features, one for each tooling member, with the first and second tooling members being received in respective receiving features of the paste shield to releasably secure the paste shield. The squeegee drip collection assembly further may include at least one extension mechanism configured to move the paste shield between the retracted position and the extended position. The at least one extension mechanism may include a bracket secured to the print head gantry and an extension member that is mounted on the bracket. The extension member may include a cylinder mounted to the bracket and a rod that is reciprocally received within the piston. Each rod may include an end that is received within at least one receiving feature of the paste shield. The paste shield may be configured with a spring-loaded locking mechanism to secure the paste shield to the at least one extension mechanism within the at least one receiving feature. The stencil printer further may include a controller coupled to the print head gantry, the print head assembly and the squeegee drip collection system. The controller may be configured to control the movement of the paste shield between the retracted position and the extended position and to perform an operation to replace the paste shield.

Another aspect of the present disclosure is directed to a method of removing a paste shield configured to collect assembly material from a squeegee of a print head gantry. In one embodiment, the method comprises: positioning at least one tooling member adjacent at least one receiving feature of a paste shield; moving the paste shield toward the at least one tooling member by at least one extension mechanism; positioning the at least one tooling member within the at least one receiving feature of the paste shield to release the paste shield from the at least one extension mechanism; and supporting the paste shield with the at least one tooling member.

Embodiments of the method further include positioning the at least one tooling member within the at least one receiving feature includes positioning a downwardly extending pin of at least one tooling member within the receiving feature and triggering a spring-loaded locking mechanism to release the paste shield from the at least one extension mechanism. The at least one tooling member may include two spaced-apart tooling members, each including a pin. The at least one receiving feature may include two receiving features, with the two tooling members being received in respective receiving features of the paste shield to secure the paste shield. The at least one extension mechanism may include a bracket secured to the print head gantry and an extension member that is mounted on the bracket. The at least one extension member may include a cylinder mounted to the bracket and a rod that is reciprocally received within the piston, each rod having a head that is received within a receiving feature of the paste shield. The paste shield may be configured with a spring-loaded locking mechanism to secure the paste shield to the at least one extension mechanism.

Yet another aspect of the present disclosure is directed to a squeegee drip collection system configured to receive assembly material from at least one squeegee blade of the print head assembly. The squeegee drip collection system includes a paste shield coupled to the print head gantry and configured to be moved between a retracted position in which the paste shield is spaced from the at least one squeegee blade and an extended position in which the paste shield is positioned under the at least one squeegee blade. The squeegee drip collection system further includes a paste shield removal assembly configured to uncouple the paste shield from the print head gantry and to remove the paste shield.

DETAILED DESCRIPTION OF THE DISCLOSURE

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

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

Embodiments of the present disclosure will now be described with reference to a stencil printer used to print an assembly material, such as solder paste, onto a circuit board. One skilled in the art will appreciate, however, that embodiments of the present disclosure are not limited to stencil printers that print solder paste onto circuit boards, but rather, may be used in other applications requiring dispensing of other viscous assembly materials, such as glues and encapsulents. For example, the apparatus may be used to print epoxy for use as underfill for chip-scale packages. Further, stencil printers in accordance with embodiments of the present disclosure are not limited to those that print assembly materials on circuit boards, but rather, include those used for printing other materials on a variety of substrates, such as semiconductor wafers. Also, the terms screen and stencil may be used interchangeably herein to describe a device in a printer that defines a pattern to be printed onto a substrate. In certain embodiments, the stencil printer may include a Momentum® or an Edison™ series stencil printer platform offered by ITW Electronic Assembly Equipment of Hopkinton, Mass. An exemplary stencil printer is generally designated at5inFIG.1. In this embodiment, the stencil printer5is a Momentum® series stencil printer platform offered by ITW Electronic Assembly Equipment of Hopkinton, Mass.

Referring toFIG.2, there is generally indicated at10a stencil printer of an embodiment of the disclosure. As shown, the stencil printer10includes a frame12that supports components of the stencil printer. The components of the stencil printer may include, in part, a controller14, a display16, a stencil18, and a print head or print head assembly, generally indicated at20, which is configured to apply the solder paste in a manner described in greater detail below.

As shown inFIG.2and described below, the stencil and the print head assembly may be suitably coupled or otherwise connected to the frame12. In one embodiment, the print head assembly20may be mounted on a print head assembly gantry, generally indicated at22, sometimes referred to as a “print head gantry,” which may be mounted on the frame12. The print head assembly20includes a print head having squeegee blades, which are configured to move across the stencil18during a print operation. Specifically, the print head is configured to dispense solder paste (or another viscous material) on the stencil18and the squeegee blades are configured to force the solder paste through apertures formed in the stencil. The print head gantry22enables the print head assembly20to be moved in the y-axis direction under the control of the controller14and to apply pressure on squeegee blades of the print head assembly as it engages the stencil18. In a certain embodiment, the print head assembly20may be placed over the stencil18and may be lowered in the z-axis direction into contact and sealingly engage the stencil.

The stencil printer10may also include a conveyor system having rails (not shown) for transporting a printed circuit board (sometimes referred to as a “printed wiring board,” “substrate,” or “electronic substrate” herein) to a print position in the stencil printer. The rails sometimes may be referred to herein as a “tractor feed mechanism,” which is configured to feed, load or otherwise deliver circuit boards to the working area of the stencil printer, which may be referred to herein as a “print nest,” and to unload circuit boards from the print nest.

Referring additionally toFIG.3, the stencil printer10has a support assembly28to support the circuit board29(shown in dashed lines), which raises and secures the circuit board so that it is stable during a print operation. In certain embodiments, the substrate support assembly28further may include a particular substrate support system, e.g., a solid support, a plurality of pins or flexible tooling, which is positioned beneath the circuit board when the circuit board is in the print position. The substrate support system may be used, in part, to support the interior regions of the circuit board to prevent flexing or warping of the circuit board during the print operation.

In one embodiment, the print head assembly20may be configured to receive solder paste from a source, such as a dispenser, e.g., a solder paste cartridge, that provides solder paste to the print head assembly during the print operation. Other methods of supplying solder paste may be employed in place of the cartridge. For example, solder paste may be manually deposited between the blades or from an external source. Additionally, in a certain embodiment, the controller14may be configured to use a personal computer having a suitable operating system, such as a Microsoft Windows® operating system provided by Microsoft Corporation, with application specific software to control the operation of the stencil printer10. The controller14may be networked with a master controller that is used to control a production line for fabricating circuit boards.

In one configuration, the stencil printer10operates as follows. A circuit board29is loaded into the stencil printer10using the conveyor rails. The support assembly28raises and secures the circuit board29to a print position. The print head assembly20is then lowered in the z-axis direction until blades of the print head assembly contact the stencil18at a desired pressure. The print head assembly20is then moved in the y-axis direction across the stencil18by the print head gantry22. The print head assembly20deposits solder paste through apertures in the stencil18and onto the circuit board29. Once the print head assembly has fully traversed the stencil18across the apertures, the print head assembly is lifted off the stencil and the circuit board29is lowered back onto the conveyor rails. The circuit board29is released and transported from the stencil printer10so that a second circuit board may be loaded into the stencil printer. To print on the second circuit board29, the print head assembly is lowered in the z-axis direction into contact with the stencil and moved across the stencil18in the direction opposite to that used for the first circuit board.

An imaging system30may be provided for the purposes of aligning the stencil18with the circuit board29prior to printing and to inspect the circuit board after printing. In one embodiment, the imaging system30may be disposed between the stencil18and the support assembly28upon which a circuit board is supported. The imaging system30is coupled to an imaging gantry32to move the imaging system. In one embodiment, the imaging gantry32may be coupled to the frame12, and includes a beam that extends between side rails of the frame12to provide back-and-forth movement of the imaging system30over the circuit board29in a y-axis direction. The imaging gantry32further may include a carriage device, which houses the imaging system30, and is configured to move along the length of the beam in an x-axis direction. The construction of the imaging gantry32used to move the imaging system30is well known in the art of solder paste printing. The arrangement is such that the imaging system30may be located at any position below the stencil18and above the circuit board29to capture an image of predefined areas of the circuit board or the stencil, respectively.

After one or more applications of the solder paste to circuit boards, excess solder paste may accumulate at the bottom of the stencil18and a stencil wiper assembly, generally indicated at34, and may move beneath the stencil to remove the excess solder paste. In other embodiments, the stencil18may be moved over the stencil wiper assembly.

Referring toFIG.4, the print head assembly20is mounted on the print head gantry22to provide movement in the y-axis direction under the control of the controller14. The print head gantry22includes an elongate beam36that rides along rails38,40(FIG.3) provided on the frame12of the stencil printer10. The beam36includes a plate42having two groups of linear bearings44,46that extend in a horizontal direction on the plate, with top linear bearings44a,44bbeing disposed above bottom linear bearings46a,46b. The purpose of the linear bearings44a,44b,46a,46bwill be described in greater detail below. The print head assembly20includes a print head48, which is coupled to the beam36of the print head gantry22. Specifically, the print head48is mounted on a carriage50fixedly mounted on the plate42. Thus, the print head gantry22provides movement of the print head48in the y-axis direction to perform the print strokes described herein. The print head48includes a squeegee blade assembly indicated at52to roll solder paste along the stencil in the manner described above. In one embodiment, the squeegee blade assembly52includes two squeegee blades, with viscous material, e.g., solder paste, disposed between the squeegee blades.

As mentioned above, solder paste can build up on squeegee blades of the squeegee blade assembly52. Unwanted solder paste drip from the squeegee blades can contaminate the operational workspace of the stencil printer10during operation. For example, when changing a stencil, such as stencil18, solder paste can drip off the squeegee blades onto the replacement stencil. Such contamination can cause defective printing operations on electronic substrates processed through the stencil printer. Aspects of the present disclosure are directed to collecting excess solder paste from squeegee blades of the squeegee blade assembly52during operation of the stencil printer10.

Referring toFIGS.5-9, embodiments of the print head assembly20further includes a squeegee drip collection system, which is configured to prevent unwanted solder paste from dripping from squeegee blades of the squeegee blade assembly52of the print head assembly20onto the stencil18during operation of the stencil printer10. The squeegee drip collection system further is configured to remove a full or otherwise contaminated paste shield from the print head gantry of the stencil printer and install a new, clean paste shield.

Specifically, the squeegee drip collection system is capable of extending and retracting a collection device, such as a paste shield, under the squeegee blades to claim or collect solder paste that drips from the squeegee blades during downtime. For example, when replacing a stencil, such as stencil18, the squeegee blades assembly52of the print head48are raised from the stencil and the paste shield of the squeegee drip collection system is deployed to collect and retain the solder paste that drips from the squeegee blades. Once the stencil18is replaced, the paste shield of the squeegee drip collection system is retracted to enable the squeegee blades from the print head48to be lowered onto the stencil18. Once full, as mentioned above, the squeegee drip collection system is configured to automatically replace a full paste shield with a new, clean paste shield.

It should be understood that the squeegee drip collection system can be utilized during other operations, including replacing tooling on the substrate support assembly, replacing squeegee blades from the squeegee blade assembly, to name a few.

Referring additionally toFIG.10, the squeegee drip collection system includes a paste shield, generally indicated at60, which can be coupled to the print head assembly20or the print head gantry22. In one embodiment, the paste shield60includes a flat bottom wall62, a front wall64, a back wall66and two side walls68,70that create a relatively shallow receptacle to receive solder paste from the squeegee blades of the squeegee blade assembly52. In another embodiment, the paste shield60includes the bottom wall62only. The front wall64includes first and second receiving features72,74that each extends beyond a peripheral edge of the front wall. In one embodiment, the receiving features72,74are part of a structure76that is secured to the paste shield60. The purpose of the receiving features72,74will be described in greater detail as the description of the squeegee drip collection system proceeds. As shown, the paste shield60has a length that generally corresponds with or is slightly longer than a length of the squeegee blades of the squeegee blade assembly52. The length and width of the paste shield60can be determined based on the size and shape of the squeegee blades of the squeegee blade assembly52.

In one embodiment, the squeegee drip collection system further includes at least one extension mechanism that is used to extend the paste shield60under the squeegee blades of the squeegee blade assembly52during operation. In the shown embodiment, two, spaced apart extension mechanisms, generally indicated at80,82, are provided to releasably secure and laterally move the paste shield60under the squeegee blades of the squeegee blade assembly52. Specifically, the extension mechanisms80,82are configured to be received in third and fourth receiving features provided in the bottom wall62or in the support structure76of the paste shield, which are positioned adjacent the first and second receiving features72,74, respectively.

FIGS.5and6illustrate the extension mechanisms80,82extending the paste shield60to the extended position to position the paste shield under the squeegee blades of the squeegee blade assembly52. The extension mechanisms80,82are configured to retract the paste shield60to enable the squeegee blade assembly52to be lowered onto the stencil18without interfering with the squeegee blade assembly. The construction of each extension mechanism80,82and the third and fourth receiving features will be described with reference toFIGS.13A-13C.

Referring back toFIGS.5-9, the collection system further includes the plate42that is mounted on the print head gantry22. The plate42includes the two pairs of linear bearings44a,44band46a,46b. As shown, linear bearings44a,46aare configured to support a first tooling member, generally indicated at86, and linear bearings44b,46bare configured to support a second tooling member, generally indicated at88, with the tooling members being configured to move laterally on their respective pairs of linear bearings.

Any suitable mechanism can be employed to move the tooling members86,88laterally along the linear bearings44a,46aand44b,46b, respectively. For example, in one embodiment, a ball screw drive assembly can be employed to move the tooling members86,88along the linear bearings44a,46aand44b,46b, respectively. In some embodiments, the ball screw drive assembly provided to move the tooling members86,88along the linear bearings44a,46aand44b,46b, respectively, can also power an up-and-down movement of the print head48in the z-axis direction. As mentioned above, the print head48of the print head assembly20is configured to be lowered to engage the stencil18during a print operation and raised to disengage the stencil when not performing a print operation. When lowered, the print head48applies pressure on the squeegee blade assembly52as the squeegee blade assembly sealingly engages the stencil18.

Referring toFIGS.10and11, the first tooling member86includes a first housing90secured to linear bearings44a,46a, with the first housing being configured to ride along the linear bearings in lateral directions. The first tooling member86further includes a first downwardly extending pin92disposed in a first pneumatic cylinder98mounted on the first housing90, the first pin having an end configured to be received within one of the receiving features, e.g., the first receiving feature72, of the paste shield60described in greater detail below.

Similarly, the second tooling member88includes a second housing94secured to linear bearings44b,46b, with the second housing being configured to ride along the linear bearings in lateral directions. The second tooling member88further includes a second downwardly extending pin96disposed in a second pneumatic cylinder100mounted on the second housing94, the second pin having an end configured to be within the other receiving feature, e.g., the second receiving feature74, of the paste shield60. The receiving features72,74of the paste shield60are configured to be engaged by the pins92,96of the first and second tooling members,86,88, respectively, to engage and move the paste shield.

The first pneumatic cylinder98and the second pneumatic cylinder100are configured to drive the up-and-down movement of the first pin92within the first housing90and the second pin96within the second housing94, respectively. The first pneumatic cylinder98and the second pneumatic cylinder100are coupled to the controller14and a pneumatic source to control the up-and-down movement of the pins92,96independently of one another.

In one embodiment, referring toFIG.7, the pins92,96of the tooling members86,88are received in respective first and second receiving features72,74of the paste shield60. The tooling members86,88can be moved to a width that is approximate to a width of the first and second receiving features72,74of the paste shield60. Once positioned in front of the first and second receiving features72,74of the paste shield60, the paste shield is moved toward the tooling members86,88by the extension mechanisms80,82so that the ends of the tooling members are received within respective receiving features of the paste shield to secure the paste shield to the tooling members. The tooling members86,88can be positioned by moving them along the linear bearings44a,46aand44b,46b, respectively. Further, the pins92,96of the tooling members86,88can be lengthened or shortened to achieve a proper elevation of the ends of the pins with respect to the first and second receiving features72,74. The print head assembly20is configured to be moved in the y-axis direction by the print head gantry22to engage and move the paste shield60. This position shown inFIGS.8and9.

It should be understood that the pins of the tooling members86,88can employ various mechanisms used to engage and move the paste shield60. In the shown embodiment, the pins92,96of the tooling members86,88have ends that are respectively received in the first and second receiving features72,74of the paste shield60. For example, the pins92,96of the tooling members86,88can each include magnets to facilitate attachment and detachment of the paste shield from the tooling members to lift and move the paste shield60.

Referring toFIGS.12A-12C, as mentioned above, the tooling members86,88can be configured to pick up and release the paste shield60. Specifically, the tooling members86,88are configured to toolessly engage and disengage the first and second receiving features72,74of the paste shield60to disengage the paste shield from the extension mechanisms80,82and to secure and remove the paste shield. As will be described in greater detail below, the paste shield60can be configured with a spring-loaded locking mechanism to secure the paste shield to the extension mechanisms80,82. A method of passively picking up and dropping off the paste shield60without needing additional axes or actuators can be performed by the tooling members86,88.

As shown inFIG.12A, for both pins92,96of tooling members86,88, as the end of the pin enters a recess of its respective receiving feature72or74, the pin causes a spring-loaded mechanism110to move against the bias of a spring to release the extension mechanism80or82from the paste shield60. Thus, the arrangement is such that as the ends of the pins92,96enter their respective third and fourth receiving features, the extension members80,82are released from the third and fourth receiving features. Once positioned, the pins92,96of the tooling members86,88are secured to the paste shield60to support the paste shield as the extension mechanisms80,82are extricated from the paste shield.

Referring toFIGS.13A-13C, each extension mechanism80,82includes a bracket114that is secured to the carriage50of the print head gantry22and an extension member116that is mounted on the bracket. As shown, in one embodiment, the extension member116includes a cylinder118mounted to the bracket114and a rod120that is reciprocally received within the cylinder. An air supply (not shown) can be connected to the cylinder118to provide the reciprocating movement of the rod120within the cylinder. The rods120of the extension members80,82are used to extend and retract the paste shield60under the squeegee blade assembly52.

Each rod120further can be configured to include an end that is received within the respective third and fourth receiving features of the paste shield60.FIG.12Billustrates the end of the rod120configured to be removed from a receiving feature122of the paste shield60.FIG.12Cillustrates the end of the rod120configured to be captured by the receiving feature122of the paste shield60.

Embodiments of the present disclosure include a method of capturing solder paste that potential can drip from squeegee blades of the squeegee blade assembly52of the print head48during operation. In one embodiment, the method includes moving the paste shield60from a retracted position to an extended position under the squeegee blades of the squeegee blade assembly52. The method further includes the ability to replace the paste shield60by use of the tooling members86,88.

In one embodiment, a method of removing the paste shield60from the squeegee blade assembly52includes positioning the tooling members86,88adjacent the receiving features72,74of the paste shield, moving the paste shield60toward the tooling members by86,88the extension mechanisms80,82, positioning the tooling members86,88within respective receiving features72,74to release the paste shield60from the extension mechanisms80,82, and supporting the paste shield60with the tooling members86,88. Although two tooling members86,88, two receiving features72,74and two extension members80,82are shown and described herein, any number of tooling members, receiving features and extension members can be provided to perform the methods described herein.

The system and related methods disclosed herein may be performed under the control of controller14. Specifically, the controller14can be configured to know when to move the paste shield and when to replace the paste shield.

In some embodiments, existing stencil printer gantries, rails and print head of the stencil printer10can be configured to shuttle items in and out, including the paste shield.

In some embodiments, the print head assembly20of the stencil printer10can be configured to move and shuttle a paste shield.

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

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

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

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

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

The concepts disclosed herein may be employed in other types of equipment used to fabricate electronic substrates, including dispensers, pick-and-place machines, reflow ovens, wave soldering machines, selective solder machines, inspection stations, and cleaning stations. For example, the concepts directed to recapturing materials can be employed in soldering and wave soldering machines and in cleaning stations.