Patent Description:
<CIT> describes a method for manufacturing a porous mold using an additive manufacturing process, the mold comprising a tool wall part having holes provided with a plurality of channels.

The invention is set out in independent claim <NUM> for a non-transitory computer-readable medium and corresponding independent method claim <NUM>.

Disclosed herein are computer-readable media, methods, and apparatuses that that identify within a curved section in a digital model of an item to be 3D fabricated, consecutive pores along the curved section that fail to comply with a predefined constraint. The item to be 3D fabricated is a device in a forming tool and/or a transfer tool. The forming tool may include a forming mold and a forming screen and the transfer tool may include a transfer mold and a transfer screen. In some examples, the item may be the forming screen, which may be mounted to an existing forming mold. The item may also or alternatively be the transfer screen, which may be mounted to an existing transfer mold. The predefined constraint includes an inter-pore distance constraint, an inter-pore cross-sectional area constraint, or a combination thereof. In addition, based on the identification of the consecutive pores along the curved section that fail to comply with the predefined constraint, the digital model is modified to remove at least some of the identified pores to cause remaining pores along the curved section to comply with the predefined constraint.

In some instances, pores may be arranged on a flattened version of an item such that the pores are evenly spaced with respect to each other. This may be done as placement of the pores in this manner may be computationally more efficient than placing the pores on the un-flattened version of the item. However, when the item is un-flattened, the even spacing of the pores may result in some of the pores, especially in a curved section, to fail to comply with the predefined constraint.

A processor executes a decimation operation to reduce a number of pores at a certain location of the digital model to thus cause the remaining pores comply with the predefined constraint. The certain location of the digital model may be a curved section having a radius of curvature that falls below a certain radius. In one example, the execution of the decimation operation may include both the removal and movement of some of the remaining pores to cause the remaining pores to be positioned at similar distances with respect to each other. In addition, the processor may sequentially execute the decimation operations on multiple portions of the pores, in which the multiple portions of the pores may include portions of the pores that intersect with an inner surface of the curved section, portions of the pores that intersect with an outer surface of the curved section, and portions of the pores that intersect with a central portion of the curved section. By sequentially executing the decimation operations on the multiple portions of the pores, the pores may be arranged such that none of the portions of the pores fail to comply with the predefined constraint.

According to examples disclosed herein, the processor modifies a digital model of an item to be 3D fabricated to remove some pores identified as failing to comply with a predefined constraint and to cause the remaining pores to comply with the predefined constraint. Particularly, the processor may execute a process that may reduce the number of pores in a curved section of the digital model <NUM> and may increase spaces between the pores in the curved section.

Through implementation of the features of the present disclosure, a processor may execute instructions to remove some of the pores and to move some or all of the remaining pores in a curved section of a digital model of an item to be 3D fabricated such that the remaining pores may comply with a predefined constraint. In one regard, the processor may execute the instructions to check whether an original placement of the pores comply with the predefined constraint, and if not, to take some actions to cause the pores to comply with the predefined constraint. By causing the remaining pores to comply with the predefined constraint, the item may be fabricated according to the modified digital model such that the item may have a reduced number or no areas that may have mechanical strengths that may be below certain levels. As a result, the item may be fabricated to be stronger and more durable, which may extend the life of the item.

A technical issue associated with conventional methods for modeling items with pores may be that the pores in curved sections may come too close to each other as the radius of curvature decreases, resulting in potential points of failures at the curved sections. Similar types of problems may exist if pores are only evaluated across a single surface or the center of the item as, for instance, some portions of the pores may be sufficiently spaced apart from each other while other portions of the pores may be too close to each other. However, conventional methods for modeling of items with pores that do not result in the potential points of failure may be computationally intensive, particularly when there are large numbers, e.g., thousands, tens of thousands, millions, etc., of pores as these methods may require the individual placements of the pores.

Through implementation of the features of the present disclosure to reduce the number of pores and the movement of the remaining pores at a curved section, the pores may be arranged in a digital model through use of a relatively simple layout of pores and the placements of the pores at the curved section may be modified to comply with a predefined constraint. The modification of the pores at the curved section may be computationally less intensive than the conventional methods discussed herein while preventing or eliminating potential points of failure at the curved sections.

Reference is first made to <FIG>, <FIG>, <FIG>. <FIG> shows a block diagram of an example computer-readable medium <NUM> that has stored thereon computer-readable instructions for modifying a digital model <NUM> of an item <NUM> to remove some pores identified as failing to comply with a predefined constraint. <FIG> shows a diagram <NUM>, which includes a processor <NUM> that may execute the computer-readable instructions stored on the example computer-readable medium <NUM> on the digital model <NUM> of the item <NUM> to generate a modified digital model <NUM>. <FIG>, respectively, depict, cross-sectional side views of example items <NUM>, in which the example items <NUM> include components of a forming tool <NUM> and/or a transfer tool <NUM>. It should be understood that the example computer-readable medium <NUM> depicted in <FIG>, the example processor <NUM> depicted in <FIG>, and/or the example items <NUM> depicted in <FIG> may include additional attributes and that some of the attributes described herein may be removed and/or modified without departing from the scopes of the example computer-readable medium <NUM>, the example processor <NUM>, and/or the example items <NUM>.

The computer-readable medium <NUM> may have stored thereon computer-readable instructions <NUM>-<NUM> that a processor, such as the processor <NUM> depicted in <FIG>, may execute. The computer-readable medium <NUM> may be an electronic, magnetic, optical, or other physical storage device that contains or stores executable instructions. The computer-readable medium <NUM> may be, for example, Random Access memory (RAM), an Electrically Erasable Programmable Read-Only Memory (EEPROM), a storage device, an optical disc, and the like. Generally speaking, the computer-readable medium <NUM> may be a non-transitory computer-readable medium, in which the term "non-transitory" does not encompass transitory propagating signals.

The processor <NUM> may fetch, decode, and execute the instructions <NUM> to obtain a digital model <NUM> of an item <NUM> to be fabricated by a three-dimensional (3D) fabrication system <NUM>. The digital model <NUM> of the item <NUM>, may be a 3D computer model of the item <NUM>, such as a computer aided design (CAD) file, or other digital representation of the item <NUM>. In addition, the processor <NUM> obtains (or equivalently, access, receive, or the like) the digital model <NUM> of the item <NUM> from a data store (not shown) or some other suitable source. In some examples, the digital model <NUM> of the item <NUM> may be generated using a CAD program or another suitable design program.

According to examples, and with reference to <FIG>, the item <NUM> may be a device that may be employed in the fabrication of a wet part <NUM> from a slurry <NUM> of a liquid and material elements. In some examples, the liquid may be water or another type of suitable liquid in which pulp material, e.g., paper, wood, fiber crops, bamboo, or the like, may be mixed into the slurry <NUM>. The material elements may be, for instance, fibers of the pulp material.

<FIG> respectively show a cross-sectional side view of a forming tool <NUM>, in which a portion of the forming tool <NUM> has been placed within a volume of the slurry <NUM>, and a cross-sectional side view of a transfer tool <NUM> that may remove the wet part <NUM> from the forming screen <NUM>. As shown in <FIG>, the forming tool <NUM> may include a forming mold <NUM> and a forming screen <NUM>, in which the forming screen <NUM> may overlay the forming mold <NUM>. As shown in <FIG>, the transfer tool <NUM> may include a transfer mold <NUM> and a transfer screen <NUM>. The forming tool <NUM> and the transfer tool <NUM> may be parts of a machine that is to form molded fiber parts from the slurry <NUM>. As discussed herein, the item <NUM> may be equivalent to any of the forming screen <NUM>, the forming mold <NUM>, the transfer mold <NUM>, and/or the transfer screen <NUM>. In some examples, however, the transfer tool may not include the transfer screen <NUM>.

In some examples, the forming mold <NUM> and/or the transfer mold <NUM> may be removably mounted onto respective supporting structures (not shown) such that, for instance, the forming mold <NUM> may be moved independently from the transfer mold <NUM>. Moreover, the forming mold <NUM> and the forming screen <NUM> may be fabricated to have shapes to which the wet part <NUM> may be molded when formed on the forming screen <NUM>. Likewise, the transfer mold <NUM> and the transfer screen <NUM> may be fabricated to have shapes that may engage multiple surfaces of the wet part <NUM> formed on the forming screen <NUM>. The transfer screen <NUM> may have a shape that is complementary to the shape of the forming screen <NUM>.

As shown, the forming mold <NUM> may be formed to have a relatively larger thickness than the forming screen <NUM> and the transfer mold <NUM> may be formed to have a relatively larger thickness than the transfer screen <NUM>. In some examples, the transfer screen <NUM> and the forming screen <NUM> may have the same or similar thicknesses and/or the transfer mold <NUM> and the forming mold <NUM> may have the same or similar thicknesses. The larger thicknesses of the forming mold <NUM> and the transfer mold <NUM> may cause the forming mold <NUM> and the transfer mold <NUM> to be substantially more rigid than the forming screen <NUM> and the transfer screen <NUM>. The forming mold <NUM> may thus provide structural support for the forming screen <NUM> and the transfer mold <NUM> may provide structural support for the transfer screen <NUM>.

In some examples, different versions of the forming screen <NUM> may be mounted to the forming mold <NUM> to form wet parts <NUM> having different details. For instance, a first forming screen <NUM> may include a first feature that may be imprinted onto the wet part <NUM> as a first detail and a second forming screen <NUM> may include a second feature that may be imprinted onto the wet part <NUM> as a second detail, in which the first detail and the second detail may be 3D logos, predefined embossed textures, embossed text, embossed designs, and/or the like. In this regard, different details may be added to the wet part <NUM> through the use of different forming screens <NUM>, while using the same forming mold <NUM>, which may simplify the formation of wet parts <NUM> having various details.

Likewise, different versions of the transfer screen <NUM> may be mounted to the transfer mold <NUM> to imprint different details onto a surface (or multiple surfaces) of the wet parts <NUM>. For instance, a first transfer screen <NUM> may include a first feature that may be imprinted onto the wet part <NUM> as a first detail when the first transfer screen <NUM> is engaged with the wet part <NUM> and a second transfer screen <NUM> may include a second feature that may be imprinted onto the wet part <NUM> as a second detail when the second transfer screen <NUM> is engaged with the wet part <NUM>. The first feature and the second feature may each be a positive, a negative, or a combination of both, relief formed in their respective transfer screens <NUM>. The first detail and the second detail may also include 3D logos, predefined 3D textures, 3D text, 3D designs, and/or the like. In this regard, different details may be formed on the wet part <NUM> through the use of different transfer screens <NUM>, while using the same transfer mold <NUM>, which may also simplify the formation of wet parts <NUM> having various details. In some examples, the features on the transfer screen <NUM> may be complementary versions of features on the forming screen <NUM> such that, for instance, a common detail may be formed on both opposite surfaces on the wet part <NUM>. In one regard, having such a paired transfer screen <NUM> and forming screen <NUM> may help enhance the quality of such details on formed wet parts <NUM>.

The forming mold <NUM> and/or the forming screen <NUM> may include a mechanism for the forming screen <NUM> to be mounted to the forming mold <NUM>. Likewise, the transfer mold <NUM> and/or the transfer screen <NUM> may include a mechanism for the transfer screen <NUM> to be mounted to the transfer mold <NUM>. In either case, the mechanism may include mechanical fasteners, detents, and/or the like to enable the forming screen <NUM> to be removably mounted onto the forming mold <NUM> and/or the transfer screen <NUM> to be removably mounted onto the transfer mold <NUM>. The mechanism that mounts the forming screen <NUM> to the forming mold <NUM> and/or that mounts the transfer screen <NUM> to the transfer mold <NUM> may be a quick release mechanism to enable the forming screen <NUM> and/or the transfer screen <NUM> to easily be released from the respective forming mold <NUM> and transfer mold <NUM>. This may facilitate replacement of the forming screen <NUM> and/or the transfer screen <NUM> for maintenance purposes and/or for screens <NUM>, <NUM> having different features to be employed in the formation of wet parts <NUM>.

As also shown in <FIG>, each of the forming mold <NUM>, the forming screen <NUM>, the transfer mold <NUM>, and the transfer screen <NUM> may include respective pores <NUM>, <NUM>, <NUM>, <NUM> that may extend completely through respective top and bottom surfaces of the forming mold <NUM>, the forming screen <NUM>, the transfer mold <NUM>, and the transfer screen <NUM>. The pores <NUM>, <NUM> respectively in the forming screen <NUM> and the transfer screen may be significantly smaller than the pores <NUM>, <NUM> respectively in the forming mold <NUM> and the transfer mold <NUM>. In addition, a plurality of structural features, such as pillars (not shown) may be provided between the surfaces of the forming mold <NUM> and the forming screen <NUM> and between the transfer mold <NUM> and the transfer screen <NUM> that are respectively adjacent and face each other to enable liquid to flow laterally between the forming mold <NUM> and the forming screen <NUM> and between the transfer mold <NUM> and the transfer screen <NUM>. As some of the pores <NUM> in the forming screen <NUM> may not directly align with the pores <NUM> in the forming mold <NUM> and some of the pores <NUM> in the transfer screen <NUM> may not directly align with the pores <NUM> in the transfer mold <NUM>, the channels formed by the structural features may enable liquid to flow through those pores <NUM>, <NUM> in addition to the pores <NUM>, <NUM> that are directly aligned with the respective pores <NUM>, <NUM>.

Although not shown, the forming tool <NUM> may be in communication with a plenum to which a vacuum source may connected such that the vacuum source may apply a vacuum pressure through the pores <NUM>, <NUM>. When the vacuum pressure is applied through the pores <NUM>, <NUM>, some of the liquid in the slurry <NUM> may be suctioned through the pores <NUM>, <NUM> and may flow into the plenum as denoted by the arrows <NUM>. As the liquid flows through the pores <NUM>, <NUM>, the forming screen <NUM> may prevent the material elements in the slurry <NUM> from flowing through the pores <NUM>. That is, the pores <NUM> may have sufficiently small dimensions, e.g., diameters or widths, that may enable the liquid to flow through the pores <NUM> while blocking the material elements from flowing through the pores <NUM>. In one regard, the diameters or widths of the pores <NUM> may be sized based on sizes of the material elements, e.g., fibers, in the slurry <NUM>. By way of particular example, the pores <NUM> may have diameters of around <NUM>. However, in some instances, the pores <NUM> may have irregular shapes as may occur during 3D fabrication processes.

Over a period of time, which may be a relatively short period of time, e.g., about a few seconds, less than about a minute, less than about five minutes, or the like, the material elements may build up on the forming screen <NUM>. Particularly, the material elements in the slurry <NUM> may be accumulated and compressed onto the forming screen <NUM> into the wet part <NUM>. The wet part <NUM> may take the shape of the forming screen <NUM>. In addition, the thickness and density of the wet part <NUM> may be affected by the types and/or sizes of the material elements in the slurry <NUM>, the length of time that the vacuum pressure is applied while the forming mold <NUM> and the forming screen <NUM> are placed within the volume of the slurry <NUM>, etc. That is, for instance, the longer that the vacuum pressure is applied while the forming mold <NUM> and the forming screen <NUM> are partially immersed in the slurry <NUM>, the wet part <NUM> may be formed to have a greater thickness.

After a predefined period of time, e.g., after the wet part <NUM> having desired properties has been formed on the forming screen <NUM>, the forming mold <NUM> and the forming screen <NUM> may be removed from the volume of slurry <NUM>. For instance, the forming mold <NUM> may be mounted to a movable mechanism that may move away from the volume of slurry <NUM>. In some examples, the movable mechanism may rotate with respect to the volume such that rotation of the movable mechanism may cause the forming mold <NUM> and the forming screen <NUM> to be removed from the volume of slurry <NUM>. In other examples, the movable mechanism may be moved laterally with respect to the volume of slurry <NUM>. As the forming mold <NUM> and the forming screen <NUM> are removed from the volume, some of the excess slurry <NUM> may come off of the wet part <NUM>. However, the wet part <NUM> may have a relatively high concentration of liquid.

Following the formation of the wet part <NUM> on the forming screen <NUM> and movement of the forming screen <NUM> and the wet part <NUM> out of the volume of slurry <NUM>, the transfer tool <NUM> may be moved such that the transfer screen <NUM> may contact the wet part <NUM> on the forming screen <NUM>. That is, for instance, the transfer mold <NUM> may be attached to a movable mechanism (not shown), in which the movable mechanism may cause the transfer mold <NUM> and the transfer screen <NUM> to move toward the forming screen <NUM>. In some examples, the transfer tool <NUM> may be moved to cause the transfer screen <NUM> to be in contact with the wet part <NUM> prior to the wet part <NUM> being de-watered while on the forming screen <NUM>, e.g., within a few seconds of the wet part <NUM> being removed from the volume of slurry <NUM>. In one regard, the transfer tool <NUM> may engage the wet part <NUM> relatively quickly after formation of the wet part <NUM>, which may enable the transfer tool <NUM> to remove the wet part <NUM> relatively quickly and the forming tool <NUM> to be inserted into the volume of slurry <NUM> to form a next wet part <NUM>.

In addition, the transfer tool <NUM> may be in communication with a plenum to which a vacuum source may be connected such that the vacuum source may apply a vacuum pressure through the pores <NUM>, <NUM> while the wet part <NUM> is in contact with the transfer screen <NUM>. The vacuum source may be the same or a different vacuum source to which the forming tool <NUM> may be in communication. The vacuum pressure applied through the forming tool <NUM> may be terminated or reversed (e.g., applied in the opposite direction) while the vacuum pressure is applied through the transfer tool <NUM>. As such, the wet part <NUM> may be biased toward the transfer tool <NUM> as opposed to the forming tool <NUM>. While the wet part <NUM> is biased toward the transfer tool <NUM>, the transfer tool <NUM> may be moved away from the forming tool <NUM> such that the transfer tool <NUM> may remove the wet part <NUM> from the forming tool <NUM>.

As shown in <FIG>, the transfer screen <NUM> may include pores <NUM> across multiple surfaces of the transfer screen <NUM>. In some examples, the pores <NUM> may be positioned deterministically in the transfer screen <NUM> to cause pressure to be applied substantially evenly across the transfer screen <NUM> when the vacuum pressure is applied. As a result, pressure may be applied substantially evenly across the surface of the wet part <NUM> that is in contact with the transfer screen <NUM>. This may prevent the application of increased pressure at a particular location on the surface of the wet part <NUM>, which may prevent the wet part <NUM> from being damaged by the application of the pressure onto the wet part <NUM> through the transfer screen <NUM>. Additionally, this may enable the transfer tool <NUM> to remove wet parts <NUM> having a vertically or substantially vertically extending (e.g., zero draft) surface (or surfaces) from the forming screen <NUM> as the pressure may be sufficient to overcome frictional and other forces applied by the forming screen <NUM> onto the wet part <NUM>.

When the wet part <NUM> is in contact with the transfer screen <NUM>, the wet part <NUM> may include some of the liquid from the slurry <NUM>. In addition, when the vacuum pressure is applied through the pores <NUM>, <NUM>, some of the liquid in the wet part <NUM> may be suctioned through the pores <NUM>, <NUM> and may flow into the plenum as denoted by the arrows <NUM>. As the liquid flows through the pores <NUM>, <NUM>, the transfer screen <NUM> may prevent the material elements in the wet part <NUM> from flowing through the pores <NUM>. That is, the pores <NUM> may have sufficiently small dimensions, e.g., diameters or widths, that may enable the liquid to flow through the pores <NUM> while blocking the material elements from flowing through the pores <NUM>. In one regard, the diameters or widths of the pores <NUM> may be sized based on sizes of the material elements, e.g., fibers, in the slurry <NUM>. By way of particular example, the pores <NUM> may have diameters of around <NUM> or smaller. However, in some instances, the pores <NUM> may have irregular shapes as may occur during 3D fabrication processes.

In one regard, the application of the vacuum pressure through the pores <NUM>, <NUM> may de-water the wet part <NUM> by removing some of the liquid from the wet part <NUM>. As a result, when the wet part <NUM> undergoes drying, for instance, in an oven, the amount of energy and/or the amount of time to dry the wet part <NUM> may significantly be reduced.

In another regard, the application of vacuum pressure through the pores <NUM>, <NUM> may cause the material elements at the surface of the wet part <NUM> that is contact with the transfer screen <NUM> to have a greater density than the material elements closer to the center of the wet part <NUM>. As a result, the wet part <NUM> may resist warpage during drying of the wet part <NUM>, for instance, in an oven, due to a greater level of symmetrical shrinkage afforded by the denser surface matching the similarly dense surface on the forming screen <NUM> side of the wet part <NUM>. Additionally, the surface may be relatively smoother than when the wet part <NUM> is allowed to de-water without the application of pressure onto the surface of the wet part <NUM>.

As the liquid flows through the pores <NUM>, <NUM>, the transfer screen <NUM> the material elements in the wet part <NUM> may be prevented from flowing through the pores <NUM>. That is, the pores <NUM> may have sufficiently small dimensions, e.g., diameters or widths, that may enable the liquid to flow through the pores <NUM> while blocking the material elements from flowing through the pores <NUM>. In one regard, the diameters or widths of the pores <NUM> may be sized based on sizes of the material elements, e.g., fibers, in the slurry <NUM>.

According to examples, the pores <NUM>, <NUM> may respectively be positioned in the forming mold <NUM> and the forming screen <NUM> and may have properties, e.g., sizes and/or shapes, such that wet part <NUM> may be formed with predefined characteristics. For instance, the pores <NUM>, <NUM> may be positioned and may have certain properties to cause the wet part <NUM> to be formed to have an intended thickness (or thicknesses) throughout the wet part <NUM>. By way of particular example, the pores <NUM>, <NUM> may be positioned and may have certain properties to cause thicknesses of the wet part <NUM> to be consistent throughout the wet part <NUM>. As another example, the pores <NUM>, <NUM> may be positioned and may have certain properties to cause the wet part <NUM> to be formed without an area having a thickness that is below a certain threshold thickness, e.g., a thickness at which a weak point may be formed in the wet part <NUM>.

According to examples, the pores <NUM>, <NUM> may respectively be positioned in the transfer mold <NUM> and the transfer screen <NUM> and may have properties, e.g., sizes and/or shapes, such that pressure may be applied onto the wet part <NUM> as described herein. For instance, the pores <NUM>, <NUM> may be positioned and may have certain properties to cause pressure to be evenly applied across multiple surfaces of the wet part <NUM>. As other examples, the pores <NUM>, <NUM> may be positioned and may have certain properties to enable sufficient pressure to be applied across the multiple surfaces of the wet part <NUM> to suction liquid from the wet part <NUM> without, for instance, damaging the wet part <NUM>.

In some examples, the positions and/or properties of the pores <NUM>, <NUM>, <NUM>, and/or <NUM> may be determined through implementation of an algorithm that the processor <NUM> may execute. For instance, the algorithm may be a packing algorithm that may cause a maximum number of pores <NUM>, <NUM>, <NUM>, and/or <NUM> to respectively be added while causing the forming mold <NUM>, the forming screen <NUM>, the transfer mold <NUM>, and/or the transfer screen <NUM> to have certain levels of mechanical strength, e.g., to prevent weak points. In this example, the algorithm may be a sphere or ellipsoid packing algorithm or other suitable algorithm for determining placements of the pores <NUM>, <NUM>, <NUM>, and/or <NUM>.

As another example, the algorithm may be a packing algorithm that may position similarly sized pores <NUM> evenly across the forming mold <NUM> and/or similarly sized pores <NUM> evenly across the forming screen <NUM>. In this example, the processor <NUM> may execute the algorithm to place an array of pores <NUM> across a flattened version of the forming mold <NUM> or an array of pores <NUM> across a flattened version of the forming screen <NUM>. Similarly, the packing algorithm may position similarly sized pores <NUM> across the transfer mold <NUM> and/or similarly sized pores <NUM> across the transfer screen <NUM>. In this example, the processor <NUM> may execute the algorithm to place an array of pores <NUM> across a flattened version of the transfer mold <NUM> or an array of pores <NUM> across a flattened version of the forming screen <NUM>.

By placing the pores <NUM>, <NUM>, <NUM>, and/or <NUM> across the flattened versions, the processing resources and/or time consumed to arrange the pores <NUM>, <NUM>, <NUM>, and/or <NUM> may be reduced as compared with the processing resources and/or time consumed to implement other types of packing algorithms as the other types of packing algorithms may be more computationally intensive than the algorithm of this example. In any regard, following placement of the pores <NUM>, <NUM>, <NUM>, and/or <NUM>, the processor <NUM> may cause the digital model <NUM> of the item <NUM> (e.g., the forming mold <NUM>, the forming screen <NUM>, the transfer mold <NUM>, and/or the transfer screen <NUM>) to include a curved section <NUM> or multiple curved sections <NUM>.

In any of the examples described herein, the algorithm may cause the pores <NUM> to be placed with respect to each other such that the pores <NUM> comply with a predefined constraint with respect to other pores <NUM>. The algorithm may similarly cause the pores <NUM> to be placed with respect to each other such that the pores <NUM> comply with a predefined constraint with respect to other pores <NUM>, the pores <NUM> to be placed with respect to each other such that the pores <NUM> comply with a predefined constraint with respect to other pores <NUM>, and/or the pores <NUM> to be placed with respect to each other such that the pores <NUM> comply with a predefined constraint with respect to other pores <NUM>.

The predefined constraint is an inter-pore distance constraint, an inter-pore cross-sectional area constraint, or a combination thereof. The inter-pore distance constraint is a constraint that is directed to a minimum distance between adjacent pores. The minimum distance corresponds to a minimum distance at which the material between the adjacent pores meets a predefined minimum strength level. The inter-pore cross-sectional area constraint is a constraint that is directed to a minimum cross-sectional area between adjacent pores. The minimum cross-sectional area corresponds to a minimum cross-sectional area at which the material between the adjacent pores meets a predefined minimum strength level. The inter-pore distance constraint and/or the inter-pore cross-sectional area constraint may be determined based on testing and/or or modeling of various inter-pore distances and/or various inter-pore cross-sectional areas and determining the minimum distance and/or minimum cross-sectional area from results of the testing and/or modeling.

With reference back to <FIG>, an enlarged version of the curved section <NUM> in the item <NUM> is depicted, in which the curved section <NUM> includes a plurality of pores <NUM>. As discussed herein, the item <NUM> represents a portion of any of the forming mold <NUM>, the forming screen <NUM>, the transfer mold <NUM>, and the transfer screen <NUM> depicted in <FIG>. In addition, the pores <NUM> may represent any of the pores <NUM>, <NUM>, <NUM>, and <NUM> depicted in <FIG>.

In some instances, such as when the angle of curvature of the curved section <NUM> falls below a certain angle, some of the pores <NUM> may violate the predefined constraint. That is, while the digital model <NUM> of the item <NUM> was in a flattened state such that the curved section <NUM> was flat, the pores <NUM> may have complied with the predefined constraint. However, when the curved section <NUM> is formed again in the digital model <NUM>, some of the pores <NUM> in the curved section <NUM> may violate the predefined constraint as the portions of the pores <NUM> along the inner surface <NUM> of the curved section <NUM> may be relatively closer to each other than the portions of the pores <NUM> along the outer surface <NUM> of the curved section. As discussed herein, the processor <NUM> may remove some of the pores <NUM> in the curved section <NUM> and may space the remaining pores <NUM> to cause the pores <NUM> in the curved section to meet the predefined constraint.

With particular reference to <FIG> and <FIG>, the processor <NUM> may fetch, decode, and execute the instructions <NUM> to identify within the digital model <NUM>, consecutive pores <NUM> along the curved section <NUM> that fail to comply with a predefined constraint. As discussed herein, the predefined constraint includes an inter-pore distance constraint, an inter-pore cross-sectional area constraint, or a combination thereof. For instance, the processor <NUM> may identify the locations of the pores <NUM>, which may be represented as points or pores in the digital model <NUM>, and based on the identified locations, may determine if any of the pores <NUM> fails to comply with the predefined constraint. In making this determination, the processor <NUM> may identify the locations of certain portions of the pores <NUM>, such as, the portions of the pores <NUM> that are along the inner surface <NUM> of the curved section <NUM>, the portions of the pores <NUM> that are along the outer surface <NUM> of the curved section <NUM>, and/or the portions of the pores <NUM> that are along a central portion <NUM> of the curved section <NUM>. The central portion <NUM> of the curved section <NUM> may extend centrally between the inner surface <NUM> and the outer surface <NUM> as shown in <FIG>.

By way of example, the processor <NUM> may determine that a first pore <NUM> may fail to comply with the predefined constraint with respect to a second pore <NUM> and that the second pore <NUM> may violate the predefined constraint with respect to the first pore <NUM>. The processor <NUM> may make this determination based on the distances between centers of the pores <NUM> and <NUM> along the inner surface <NUM>, the distances between centers of the pores <NUM> and <NUM> along the outer surface <NUM>, and/or the distances between centers of the pores <NUM> and <NUM> along the central portion <NUM>. In other examples, the processor <NUM> may make this determination based on the distances between respective edges of the pores <NUM> and <NUM>. In some examples in which the predefined constraint is an inter-pore constraint, the processor <NUM> may determine that the first pore <NUM> and the second pore <NUM> may violate the inter-pore constraint based on the identified distance between portions of the first pore and the second pore <NUM>. In some examples in which the predefined constraint is an inter-pore cross-sectional area constraint, the processor <NUM> may determine the cross-sectional area between the first pore <NUM> and the second pore <NUM>.

The processor <NUM> may fetch, decode, and execute the instructions <NUM> to, based on the identification of the consecutive pores <NUM>, <NUM> along the curved section <NUM> that fail to comply with the predefined constraint, modify the digital model <NUM> to remove at least some of the identified pores <NUM>, <NUM> to cause remaining pores <NUM> along the curved section <NUM> to comply with the predefined constraint. Particularly, for instance, the processor <NUM> executes a decimation operation on the pores <NUM> that are identified as failing to comply with the predefined constraint to remove some of the pores <NUM>. In performing the decimation operation, the processor <NUM> removes some of the pores <NUM> (or may combine some of the pores <NUM>) and may move some of the remaining pores <NUM> to cause distances between the remaining pores <NUM> to be averaged with respect to each other. That is, the processor <NUM> may space the remaining pores <NUM> with respect to each other such that the distances between adjacent ones of the remaining pores <NUM> are constant with respect to each other. For instance, the processor <NUM> may space the remaining pores <NUM> with respect to each other such that the distances of the centers of the remaining pores <NUM> are the same with respect to each other.

According to examples, the processor <NUM> may execute the decimation operation on multiple portions of the pores <NUM> to ensure that each of the pores <NUM> at the multiple portions comply with the predefined constraint. The multiple portions may include portions that are along the inner surface <NUM>, portions that are along the outer surface <NUM>, and portions that are along the central portion <NUM> of the curved section <NUM>. That is, for instance, the processor <NUM> may execute the decimation operation to modify the digital model <NUM> to remove at least some of the identified pores <NUM> to cause remaining pores along the curved section <NUM> to comply with the predefined constraint following identification of the consecutive pores <NUM> based on the determined locations at which the consecutive pores intersect with one of the inner surface <NUM>, the outer surface <NUM>, and the central portion <NUM>. By way of example, the processor <NUM> may execute the decimation operation based on the determined locations at which the consecutive pores intersect with the central portion <NUM>.

In a second execution of the decimation operation, the processor <NUM> may identify consecutive pores <NUM> along the curved section <NUM> that fail to comply with the predefined constraint based on the determined locations at which the consecutive pores <NUM> intersect with another one of the inner surface <NUM>, the outer surface <NUM>, and the central portion <NUM>. By way of example, the processor <NUM> may execute the decimation operation based on the determined locations at which the consecutive pores intersect with the outer surface <NUM>. In addition, the processor <NUM> modify the digital model <NUM> to remove at least some of the identified pores <NUM> to cause remaining pores along the curved section <NUM> to comply with the predefined constraint following identification of the consecutive pores <NUM> based on the determined locations at which the consecutive pores intersect with the other one of the inner surface <NUM>, the outer surface <NUM>, and the central portion <NUM> (e.g., the outer surface <NUM>).

In a third execution of the decimation operation, the processor <NUM> may, following modification of the digital model <NUM> to remove at least some of the identified pores <NUM> to cause remaining pores <NUM> along the curved section <NUM> to comply with the predefined constraint, identify consecutive pores <NUM> along the curved section that fail to comply with the predefined constraint based on the determined locations at which the consecutive pores intersect with a last one of the inner surface <NUM>, the outer surface <NUM>, and the central portion <NUM> (e.g., the inner surface <NUM>).

As shown in <FIG>, a modified digital model <NUM> of the item <NUM> may include a fewer number of pores <NUM> than the original digital model <NUM>, in which the placements of the pores <NUM> may comply with the predefined constraint. In addition, the centers of the pores <NUM>, e.g., along the central portion <NUM>, may be averaged with respect to each other.

According to examples, the processor <NUM> may send the modified digital model <NUM> to the 3D fabrication system <NUM>, in which the 3D fabrication system <NUM> is to fabricate the item <NUM> with the plurality of pores <NUM> placed in compliance with the predefined constraint. The processor <NUM> may also send the modified digital model <NUM> to a controller or processor of the 3D fabrication system <NUM>, which may process or otherwise use the modified digital model <NUM> to fabricate the item <NUM>. In other examples, the processor <NUM> may be the controller or processor of the 3D fabrication system <NUM>.

In some examples, the processor <NUM> may be part of an apparatus <NUM>, which may be a computing system such as a server, a laptop computer, a tablet computer, a desktop computer, or the like. The processor <NUM> may be a semiconductor-based microprocessor, a central processing unit (CPU), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), and/or other suitable hardware device. The apparatus <NUM> may also include a memory that may have stored thereon computer-readable instructions (which may also be termed computer-readable instructions) that the processor <NUM> may execute. The memory may be an electronic, magnetic, optical, or other physical storage device that contains or stores executable instructions. The memory may be, for example, Random Access memory (RAM), an Electrically Erasable Programmable Read-Only Memory (EEPROM), a storage device, an optical disc, and the like. The memory, which may also be referred to as a computer-readable storage medium, may be a non-transitory computer-readable storage medium, where the term "non-transitory" does not encompass transitory propagating signals.

The 3D fabrication system <NUM> may be any suitable type of additive manufacturing system. Examples of suitable additive manufacturing systems may include systems that may employ curable binder jetting onto build materials (e.g., thermally or UV curable binders), ink jetting onto build materials, selective laser sintering, stereolithography, fused deposition modeling, etc. In a particular example, the 3D fabrication system <NUM> may form the item <NUM> by binding and/or fusing build material particles together. In any of these examples, the build material particles may be any suitable type of material that may be employed in 3D fabrication processes, such as, a metal, a plastic, a nylon, a ceramic, an alloy, and/or the like. Generally speaking, higher functionality/performance transfer screens <NUM> may be those with the smallest pore size to block fibers of smaller sizes, and hence some 3D fabrication system technologies may be more suited for generating the transfer screens <NUM> than others.

Turning now to <FIG>, there is shown a flow diagram of an example method <NUM> for modifying a digital model <NUM> of an item <NUM> to remove some pores <NUM> identified as failing to comply with a predefined constraint and to cause the remaining pores along the curved section <NUM> to comply with the predefined constraint. It should be understood that the method <NUM> depicted in <FIG> may include additional operations and that some of the operations described therein may be removed and/or modified without departing from the scope of the method <NUM>. The description of the method <NUM> is also made with reference to the features depicted in <FIG> for purposes of illustration. Particularly, the processor <NUM> may execute some or all of the operations included in the method <NUM>.

At block <NUM>, the processor <NUM> obtains a digital model <NUM> of an item <NUM> to be fabricated by a 3D fabrication system <NUM>. As discussed herein, the digital model <NUM> may include a plurality of pores <NUM> or a plurality of pores <NUM> are to be added algorithmically to the digital model <NUM>, in which the pores <NUM> traverse a curved section <NUM> of the digital model <NUM>. In addition, at block <NUM>, the processor <NUM> identifies consecutive pores <NUM> along the curved section <NUM> and at block <NUM>, the processor <NUM> determines whether any of the consecutive pores <NUM> fails to comply with a predefined constraint, in which the predefined constraint include an inter-pore distance constraint, an inter-pore cross-sectional area constraint, or a combination thereof.

At block <NUM>, the processor <NUM>, based on at least one of the pores <NUM> failing to comply with the predefined constraint, modifies the digital model <NUM> to remove at least some of the identified pores <NUM> to cause remaining pores <NUM> along the curved section <NUM> to comply with the predefined constraint. At block <NUM>, the processor <NUM> causes a 3D fabrication system <NUM> to fabricate the item <NUM> according to the modified digital model <NUM>. The processor <NUM> may send the modified digital model <NUM> to the 3D fabrication system <NUM> and a controller or a processor of the 3D fabrication system <NUM> may fabricate the item <NUM> according to the modified digital model <NUM>. In other examples, the processor <NUM> may be a processor of the 3D fabrication system <NUM> and the processor <NUM> may control the 3D fabrication system <NUM> to fabricate the item <NUM> according to the modified digital model <NUM>. The fabricated item <NUM> may be used to form wet parts <NUM>, e.g., molded fiber articles.

As discussed herein, the curved section <NUM> may include an inner surface <NUM> and an outer surface <NUM> and the processor <NUM> may execute decimation operations on multiple portions of the pores <NUM> to, for instance, verify that the multiple portions of the pores <NUM> comply with the predefined constraint. In addition, the processor may identify a central portion <NUM> of the curved section <NUM>, in which the central portion may extend centrally between the inner surface <NUM> and the outer surface <NUM>. The processor <NUM> may also determine locations at which the consecutive pores <NUM> intersect with the inner surface <NUM>, the outer surface <NUM>, and the central portion <NUM>. In addition, the processor <NUM> may identify the consecutive pores <NUM> along the curved section <NUM> that fail to comply with the predefined constraint based on the determined locations at which the consecutive pores <NUM> intersect with one of the inner surface <NUM>, the outer surface <NUM>, and the central portion <NUM>.

Following identification of the consecutive pores <NUM> based on the determined locations at which the consecutive pores <NUM> intersect with one of the inner surface <NUM>, the outer surface <NUM>, and the central portion <NUM>, and modification of the digital model <NUM> to remove of at least some of the identified pores, the processor <NUM> may modify the digital model <NUM> to move some of the remaining pores <NUM> to cause distances between the remaining pores <NUM> to be averaged with respect to each other. Following modification of the digital model to move some of the remaining pores, the processor <NUM> may identify consecutive pores <NUM> along the curved section <NUM> that fail to comply with the predefined constraint based on the determined locations at which the consecutive pores <NUM> intersect with another one of the inner surface <NUM>, the outer surface <NUM>, and the central portion <NUM>. In addition, the processor <NUM> may modify the digital model <NUM> to remove some of the remaining pores <NUM> and following modification of the digital model <NUM> to remove some of the remaining pores <NUM>, the processor <NUM> may modify the digital model <NUM> to move some of the remaining pores <NUM> to cause distances between the remaining pores <NUM> to be averaged with respect to each other.

Following modification of the digital model <NUM> to move some of the remaining pores <NUM>, the processor <NUM> may identify the consecutive pores <NUM> along the curved section <NUM> that fail to comply with the predefined constraint based on the determined locations at which the consecutive pores <NUM> intersect with a last one of the inner surface <NUM>, the outer surface <NUM>, and the central portion <NUM>. In addition, the processor <NUM> may modify the digital model <NUM> to move some of the remaining pores <NUM> to cause distances between the remaining pores <NUM> to be averaged with respect to each other. The processor causes the 3D fabrication system <NUM> to fabricate the item <NUM> based on the modified digital model <NUM>.

With reference back to block <NUM>, based on a determination that the curved section <NUM> does not include consecutive pores that fail to comply with the predefined constraint, at block <NUM>, the processor <NUM> may maintain the pore <NUM> placements. In addition, the processor <NUM> causes the 3D fabrication system <NUM> to fabricate the item <NUM> based on the digital model <NUM>.

Some or all of the operations set forth in the method <NUM> may be contained as utilities, programs, or subprograms, in any desired computer accessible medium. In addition, the method <NUM> may be embodied by computer programs, which may exist in a variety of forms. For example, the method <NUM> may exist as computer-readable instructions, including source code, object code, executable code or other formats. Any of the above may be embodied on a non-transitory computer readable storage medium.

Examples of non-transitory computer readable storage media include computer system RAM, ROM, EPROM, EEPROM, and magnetic or optical disks or tapes. It is therefore to be understood that any electronic device capable of executing the above-described functions may perform those functions enumerated above.

Reference is now made to <FIG>. <FIG> shows a block diagram of an example computer-readable medium <NUM> that may have stored thereon computer-readable instructions for modifying a digital model <NUM> of an item <NUM> to remove some pores identified as failing to comply with a predefined constraint and to cause the remaining pores to comply with the predefined constraint. <FIG> shows diagram <NUM>, which includes a processor <NUM> that may execute the computer-readable instructions stored on the computer-readable medium <NUM> depicted in <FIG> on the digital model <NUM> of the item <NUM>. <FIG>, respectively, depict, diagrams of an example flattened digital model <NUM> at various stages of processing. It should be understood that the example computer-readable medium <NUM> depicted in <FIG>, the example processor <NUM> depicted in <FIG>, and/or the example flattened digital model <NUM> depicted in <FIG> may include additional attributes and that some of the attributes described herein may be removed and/or modified without departing from the scopes of the example computer-readable medium <NUM>, the example processor <NUM>, and/or the example flattened digital model <NUM>.

<FIG> include reference numerals that are the same as reference numerals used in <FIG>. It should be understood that like reference numerals correspond to the same elements in all of the figures. Accordingly, elements corresponding to reference numerals that have previously been described are not described again in detail with respect to <FIG>.

Generally speaking, the processor <NUM> may execute the instructions <NUM>-<NUM> in instances in which a curved section <NUM> has a small angle of curvature that may result in some of the pores <NUM> in the curved section <NUM> to fail to comply with a predefined constraint. Particularly, the processor <NUM> may execute the instructions to remove or reduce a number of the pores <NUM> in the curved section <NUM> such that the reduced number of the pores <NUM> may be arranged to comply with the predefined constraint.

The processor <NUM> may fetch, decode, and execute the instructions <NUM> to determine a length <NUM> of an inner surface <NUM> of a curved section <NUM> of a digital model <NUM> of a developable portion of an item <NUM> to be fabricated by a 3D fabrication system <NUM>. The developable portion of the item <NUM> may be a portion of the item <NUM> that includes a single curvature surface that may be digitally unrolled to be flat and then rolled back to its original shape without distortion. In addition, the length <NUM> of the inner surface <NUM> may correspond to a distance that extends from a first point that is at an intersection between an initial portion of the curved section <NUM> as denoted by the dashed line <NUM> and the inner surface <NUM> and a second point that is at an intersection between a final portion of the curved section <NUM> as denoted by the dashed line <NUM> and the inner surface <NUM>. The initial portion of the curved section <NUM> may be a portion at which the curved section begins to curve from a flat section and the final portion of the curved section <NUM> may be a portion at which the curve in the curved section <NUM> ends.

The processor <NUM> may fetch, decode, and execute the instructions <NUM> to determine a length <NUM> of an outer surface <NUM> of the curved section <NUM>. The length <NUM> of the outer surface <NUM> may correspond to a distance that extends from a first point that is at an intersection between an initial portion of the curved section <NUM> as denoted by the dashed line <NUM> and the outer surface <NUM> and a second point that is at an intersection between a final portion of the curved section <NUM> as denoted by the dashed line <NUM> and the outer surface <NUM>.

The processor <NUM> may fetch, decode, and execute the instructions <NUM> to calculate a ratio of the length <NUM> of the inner surface <NUM> and the length <NUM> of the outer surface <NUM>.

The processor <NUM> may fetch, decode, and execute the instructions <NUM> to digitally flatten the digital model <NUM> and the instructions <NUM> to identify a span <NUM> in the flattened digital model <NUM> corresponding to the curved section <NUM>. A cross-sectional view of the flattened digital model <NUM> including the identified span <NUM> is depicted in <FIG>. As shown in <FIG>, the span <NUM> may correspond to the initial portion of the curved section <NUM> as denoted by the dashed line <NUM> and the final portion of the curved section <NUM> as denoted by the dashed line <NUM>.

The processor <NUM> may fetch, decode, and execute the instructions <NUM> to scale down the identified span <NUM> in one dimension according to the calculated ratio. That is, for instance, the length of the span <NUM> may be multiplied by the calculated ratio of the inner surface length <NUM> to the outer surface length <NUM>. As the calculated ratio is less than one, the length of the span <NUM> will be reduced as shown in <FIG>, which shows a scaled-down span <NUM>. In addition, the length of the span <NUM> may be reduced in a dimension at which the curved section <NUM> extends, e.g., perpendicular to the axis about which the curved section <NUM> is angled. In reducing the length of the span <NUM>, the portions of the flattened digital model <NUM> outside of the span <NUM> may not be reduced.

The processor <NUM> may fetch, decode, and execute the instructions <NUM> to apply a layout <NUM> of a plurality of pores <NUM> across the flattened digital model <NUM> with the scaled-down span <NUM>. A top view of the flattened digital model <NUM> with the scaled-down span <NUM> and the layout <NUM> of the pores <NUM> are depicted in <FIG>. As shown, the layout <NUM> may include the plurality of pores <NUM> arranged to be evenly spaced with respect to each other across the flattened digital model <NUM>. In other examples, however, the layout <NUM> may include other arrangements of pores <NUM>, e.g., sections having different concentrations of pores <NUM> with respect to each other. In addition, although the layout <NUM> is depicted as pores <NUM>, the layout <NUM> may instead depict points, which may be replaced with pores <NUM> at a later stage.

It should be noted that the scaled-down span <NUM> may include a fewer number of pores <NUM> than the original span <NUM> when the layout <NUM> is overlaid on the flattened digital model <NUM>. In some examples, the processor <NUM> may return the scaled-down span <NUM> back to the original size, while maintaining the number of pores <NUM> as identified in the scaled-down span <NUM>. In addition, the pores <NUM> in the span <NUM> with the reduced number of pores <NUM> may be spaced apart from each other, for instance, such that the pores <NUM> are evenly spaced apart from neighboring pores <NUM>. As the size of the span <NUM> may be larger than the scaled-down span <NUM>, the pores <NUM> in the span <NUM> may now have greater spacings between the pores <NUM> as shown in <FIG>.

The processor <NUM> may fetch, decode, and execute the instructions <NUM> to modify the digital model <NUM> by providing the applied layout <NUM> of the plurality of pores <NUM> on the digital model <NUM> to cause pores <NUM> in the curved section <NUM> to comply with a predefined constraint. That is, the processor <NUM> may modify the digital model <NUM> to generate a modified digital model <NUM> as shown in <FIG>, in which the modified digital model <NUM> may include pores <NUM> that may be spaced further apart from each other than the digital model <NUM>. The processor <NUM> may digitally roll up the developable portion with the curved section scaled back to an initial size while maintaining a number of pores applied to the scaled down span <NUM> as shown in <FIG>. The modified digital model <NUM> may be the rolled up version of the flattened digital model <NUM> depicted in <FIG>.

The processor <NUM> may fetch, decode, and execute the instructions <NUM> to cause a 3D fabrication system <NUM> to fabricate the item <NUM> according to the modified digital model <NUM>. Thus, the processor <NUM> may cause the item <NUM>, which, as discussed herein, is a forming mold <NUM>, a forming screen <NUM>, a transfer mold <NUM>, and/or a transfer screen <NUM>, to be fabricated with pores <NUM> as arranged in the modified digital model <NUM>.

Claim 1:
A non-transitory computer-readable medium (<NUM>, <NUM>) on which is stored computer-readable instructions that when executed by a processor (<NUM>), cause the processor (<NUM>) to:
obtain a digital model (<NUM>) of an item (<NUM>) to be fabricated by a three-dimensional (3D) fabrication system (<NUM>), the digital model (<NUM>) including either a plurality of pores or the digital model (<NUM>) to be processed to algorithmically add a plurality of pores to the digital model (<NUM>), wherein the pores traverse a curved section (<NUM>) of the digital model (<NUM>);
identify within the digital model (<NUM>), pores along the curved section (<NUM>) that fail to comply with a predefined constraint, wherein the predefined constraint comprises an inter-pore distance constraint, an inter-pore cross-sectional area constraint, or a combination thereof, wherein the inter-pore distance constraint is a minimum distance at which the material between adjacent pores meets a predefined minimum strength level and the inter-pore cross-sectional area constraint is a minimum cross-sectional area at which the material between adjacent pores meets the predefined minimum strength level;
based on the identification of the pores along the curved section (<NUM>) that fail to comply with the predefined constraint, modify the digital model (<NUM>) by executing a decimation operation on the pores that are identified as failing to comply with the predefined constraint to remove at least some of the identified pores to cause remaining pores along the curved section (<NUM>) to comply with the predefined constraint; and
cause the 3D fabrication system (<NUM>) to fabricate the item (<NUM>) according to the modified digital model (<NUM>),
wherein the item (<NUM>) to be fabricated comprises a forming mold (<NUM>), a forming screen (<NUM>), a transfer mold (<NUM>), a transfer screen, or a combination thereof.