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[0041]Certain embodiments of this application relate to the use of prefabricated support structures in 3D printing. These supports may be full model contacting supports used in deposition and extrusion-based 3D printing techniques, supports which are ultimately removed from the finished object. In some embodiments, the supports may be scaffolds, lattices, or lightweight structures, or other support configurations known in the art. By manufacturing and utilizing prefabricated support structures, several benefits to the 3D printing process are realized. For example, utilizing the prefabricated supports disclosed herein results in reduced or even eliminated waste of materials. This savings of materials results from the ability for the prefabricated supports to be used to manufacture multiple parts instead of only a single part. The prefabricated supports may also improve the performance and use of single nozzle 3D printers. This is because the use of prefabricated supports allows a single-nozzle printer to extrude different materials for the model and the support. Because the support and the object are not printed at the same time, the appropriate material can be selected for each. By utilizing different materials for the support and the object itself, the support and the model do not need to be printed in a single build process. Because they can be printed in separate build processes, a separating layer may be inserted between the support and the model which makes it easier to separate them after the object has been printed. In addition, some embodiments relate to the use of supports which form substrates upon which an object is manufactured. These substrates may also be prefabricated supports structures which are integrated into the manufactured object (as opposed to being separated from the object as is the case in traditional supports).
[0042]Certain embodiments of this application relate to systems and methods which use conformal layers to avoid inter-layer weakness in objects made using additive manufacturing processes. In particular, curved-layer fused deposition modeling technology may be utilized to provide advantages such as smoother surface finishing, control over the flexibility, torsional rigidity, and shear strength in various parts of the object which are customized not only to the anatomy of the user, but also may be customized for a specified activity. In various embodiments, the objects may include items of footwear such as insoles or midsoles. In other embodiments, the objects may be seat cushions or head rests. In general, the inventive embodiments disclosed herein may be utilized in connection with various types of customized cushioning or objects with curved surfaces, such as those designed based on anatomical characteristics of the user. In certain embodiments, systems and methods which use conformal layers to avoid inter-layer weakness in objects made using additive manufacturing processes may further utilize prefabricated support structures as discussed herein. For example, the prefabricated support structure may include a curved surface corresponding to a curved surface of an object to be manufactured, and conformal layers may be used to form the object on the prefabricated support structure. In certain aspects, “curved surfaces” may refer to all kinds of curved surfaces including, but not limited to, ruled surfaces, single curved surfaces, double curved surfaces, non-uniform rational basis splines (NURBS), etc. For example, a curved surface may be curved with respect to the Z axis (e.g., perpendicular to a build platform), may be curved with respect to the Z-axis and curved with respect to one or more of the X-axis and Y-axis (e.g., curved in the X-Y plane), curved with respect to one or more of the X-axis and Y-axis (e.g., curved in the X-Y plane), etc.
[0043]FIGS. 1A and 1B provide examples of some of the shortcomings in the current uses of supports which have been identified by the inventors. FIG. 1A is an example of an object 100 printed using an additive manufacturing device. This particular object 100 was printed using object supports in a fused deposition modelling (“FDM”) process. As is known in the art, an FDM process constructs three-dimensional objects directly from 3D CAD data. A temperature-controlled head extrudes thermoplastic material layer by layer. A typical FDM process starts with importing an STL file of a model into a pre-processing software. This model is oriented and mathematically sliced into horizontal layers varying from +/−0.01-50 mm thickness. A support structure is created where needed, based on the position and geometry of the part. After reviewing the path data and generating the toolpaths, the data is downloaded to the FDM machine which prints the object.
[0044]An FDM printer typically operates in X, Y and Z axes, drawing the model one layer at a time. This process is similar to how a hot glue gun extrudes melted beads of glue. The temperature-controlled extrusion head is fed with thermoplastic modeling material that is heated to a semi-liquid state. The head extrudes and directs the material with precision in ultrathin layers onto a fixtureless base. The result of the solidified material laminating to the preceding layer is a plastic 3D model built up one strand at a time. Once the part is completed, the support columns are removed and the surface is finished.
[0045]In the example shown in FIG. 1A, the supports have been removed from the object, but the removal of the support was not complete. Thus, the support has left a considerable amount of residue 102, which detracts from both the appearance and the quality of the finished object. Although this residue may be removed using post-processing such as sanding, for example, it illustrates one difficulty in utilizing object supports which are made from the same material as the manufactured object. In addition, using the same material for support and object makes it more difficult to remove the support. In some cases, the support may not be able to be removed at all—especially where the support contacting area is quite large and flat. In order to avoid large and flat contacting areas, to ensure that the support can be removed from the object, the contact area may be reduced. But in these instances, the surface quality of the supported area often decreases dramatically.
[0046]FIG. 1B is an example of another problematic object built using conventional support techniques. In this example, the object 120 has been built using a dual-nozzle device. The dual nozzle device built the support 122 using a first material. The object 120 is built using a second material. Although the use of different materials may make the separation of the support from the object easier, there are drawbacks with this technique as well. First, the dual-nozzle printer is more expensive and more complex to operate. This expense and complexity can make it difficult for less sophisticated users to print objects using supports. Moreover, material can trickle or seep out of one nozzle and interfere with the material extruded from the other nozzle as shown in FIG. 1B. In this particular example, the material used to make the support has seeped into the object itself. This seeped material 126 negatively impacts the appearance and quality of the finished object.
[0047]In addition to the shortcomings identified by the inventors as shown in FIGS. 1A and 1B, the inventors have recognized additional deficiencies. For example, some support generation techniques seek to reduce the volume of the support as much as possible to save time and material. However, the more the volume of the support is reduced, the greater the risk that the support will fail, resulting in a failed build process. Some techniques also seek to reduce the density of the support in order to save material and time. A reduction in density also leads to a weaker support and reduced quality of the support in how conventional supports are used in 3D printing. Recognizing these problems, the inventors conceived of a new approach to generating and using supports.
[0048]FIG. 2 provides a high level illustration of this new approach. In particular, FIG. 2 shows a high level process 200 by which a prefabricated support can be used to build an object using additive manufacturing, and also to remove the built object from the support when the build process is complete. A prefabricated/predefined support 202 is manufactured based on the design of the object/model to be printed. As will be discussed in detail below, the prefabricated support 202 may take various forms and be manufactured using various manufacturing methods. In some embodiments, the prefabricated support 202 may be manufactured using an additive manufacturing device such as a 3D printer. In these implementations, the prefabricated support may be manufactured in accordance with a support structure generated which is based directly on the shape and structure of the object to be printed. In other implementations, the prefabricated support may be manufactured using conventional manufacturing methods.
[0049]As illustrated in FIG. 2, the predefined support 202 may be formed and placed in the additive manufacturing device. The object to be built may be manufactured as a series of layers 204 deposited on top of the support 202. Depending on the type of additive manufacturing device used, layers may be deposited using an extrusion device 206 such as a print nozzle. Alternatively, where the additive manufacturing device utilizes powder melting or liquid curing, the layers may be formed using laser scanner or other similar technology. Once the extrusion device 206 has completed depositing layers to build the finished model, the model 208 may be removed from the support 202 as shown. In the use of conventional supports, at this stage the support would typically be discarded. According to certain embodiments, the support 202 may be reinserted into the machine and used again to manufacture another identical and/or similar object. This process can be repeated time and time again, each time saving considerable material and time during the build process because the support need not be re-created.
[0050]In certain embodiment, as discussed, substrates may also be prefabricated supports structures which are integrated into the manufactured object (as opposed to being separated from the object as is the case in traditional supports). Accordingly, in certain aspects, once the extrusion device 206 has completed depositing layers the finished model may include both model 208 and support 202 integrated together. The finished model including model 208 and support 202 may be removed from the additive manufacturing device. In certain embodiments, another predefined support 202 may be formed and placed in the additive manufacturing device for building another object.
[0051]Turning now to FIG. 3, an example of a static prefabricated support 302 with a completed object 304 is shown. The static prefabricated support 302 may generally be any type of support structure capable of providing necessary support to an object as it is manufactured within an additive manufacturing device. The static prefabricated support 302 may be manufactured using 3-D printing, tooling, vacuum casting, injection molding, or any other manufacturing technology. The static prefabricated support 302 may be made from various materials, including plastic, metal, wood, or other material.
[0052]In this example of the static prefabricated support 302, the support has been placed in a specific position on the build platform of the additive manufacturing device. This position is determined based on the design file associated with the object to be built. Once the prefabricated support 302 has been appropriately placed on the build platform, the additive manufacturing device may then begin the process of depositing and/or creating layers of the object 304 until the object has been completed. Thus, the use of static prefabricated supports such as support 302 may be beneficial in situations where multiple objects need to be produced, but it is impractical or cost prohibitive to create a mold or cast to manufacture the object (such as object 304) using conventional manufacturing methods. By utilizing the static prefabricated support 302, a significant amount of time and material may be saved each time a copy of the object 304 is made.
[0053]As discussed briefly above, the use of prefabricated supports may provide improved separation between the manufactured object and the support. FIG. 4 shows an example of how this improved separation may be achieved using the prefabricated supports. In this particular example, a separating layer or interface 406 is placed between a prefabricated support 402 and the object 404. More specifically, a separating layer 406 may be applied on top of the support prior to beginning the build process. The separating layer 406 may take various forms. In some embodiments, the separating layer 406 may be a masking material such as painters tape, for example. In other embodiments, a separating layer may be some form of a lubricant such as hairspray or some other coating which provides adequate stability for the object while still allowing for easy separation. In still other embodiments, a thin layer of intermediate material may be printed on top of the predefined support. For example, in a dual nozzle manufacturing device, one of the nozzles may extrude the intermediate material as a separating layer 406, and then the object 404 may be printed using the other nozzle. Of course, a skilled artisan will appreciate that embodiments may be practiced using a single nozzle device whereby materials are switched after printing the separating layer 406.
[0054]Although the prefabricated supports may be static in nature such as shown in FIG. 3, in some embodiments dynamic prefabricated supports may be utilized. FIGS. 5A and 5B provide an illustration of how dynamic prefabricated supports may be used (and re-used) to manufacture objects using an additive manufacturing device. Turning first to FIG. 5A, an implementation using dynamic beams 502 is shown. Here, a series of beams of varying height are combined on the platform in order to produce the desired shape of the support. As shown, the dynamic beams 502 may have varying heights which are positioned in order to follow the contour of the object to be printed. The beams 502 may have square edges. As a result, in order to have a free-form shape support, additional supporting material 504 may be printed on top of the dynamic beams 502 in order to conform to the actual shape of the object 506.
[0055]Turning to FIG. 5B, an illustration of how the additional supporting material 504 may be created is shown. Here, the extrusion nozzles 508 moves along the contour of the dynamic beams 502 and deposits layers of material which collectively form the additional supporting material 504 that may be used to support the object. Typically, this additional supporting material will be made from a different material than the dynamic beams 502. Utilizing a different material for the additional supporting material 504 allows for easier separation of the printed object from the dynamic beams 502. The additional supporting material 504 may also be formed of a different material than the object itself in order to provide easier separation from the manufactured object. However, in certain implementations such as single-nozzle 3-D printing devices, the additional supporting material 504 may be made from the same material as the printed object 506.
[0056]Turning back to FIG. 5A, the dynamic beams 502 may be a set of beams that is separate from the build platform and placed in the build platform to provide the support structure. If the dynamic beams 502 are separate from the build platform, the build platform in the additive manufacturing device may be configured to receive the adjustable beams and hold them in place during the build process. In some embodiments, 3-D modeling software may be configured to indicate which dynamic beams 502 should be positioned in which locations of the build platform. The build platform may be divided into a grid-like pattern such that the 3-D modeling software can output a vector location to indicate the specific location on the build platform that a dynamic beam 502 of a particular height should be placed. Alternatively, the beams may be part of the build platform itself, resulting in an adjustable build platform. In these embodiments, the build platform may be formed of a grid of beams attached to an actuation device that can raise or lower the beams according to commands from a control computer. Thus, when needed supports are generated by the 3-D modeling software, the dynamic build platform may be configured to maneuver its dynamic beams in such a way as to conform to the determined support structure.
[0057]The use of prefabricated support structures may also provide benefits with respect to building strategy. In particular, when utilizing prefabricated support structures, the build process may use traditional “flat” layering (such as fused deposition modeling), but it also may allow for the use of curved or conformal layering which may provide for improved structural integrity throughout the object. In some embodiments, a blend of flat layering and curved layering may be utilized. Accordingly, in certain embodiments, systems and methods which use conformal layers as described herein may make use of prefabricated support structures. For example, curved layers of such objects that use conformal layers may be built upon prefabricated support structures having a corresponding curved surface. Turning now to FIG. 6A, an example of traditional flat layering on top of the prefabricated support is shown. In this example, a static prefabricated support 602 is placed in the build area of an additive manufacturing device. The additive manufacturing device deposits a series of flat layers 604A on top of the prefabricated support 602. Utilizing a “flat” build strategy, nine different layers are needed to build the object 604A. Utilizing curved layering, as shown in FIG. 6B, a reduced number of layers are needed, resulting in an improved structural integrity and shorter printing time. As shown in FIG. 6B, the same object is printed using only five curved layers 604B. Thus utilizing the prefabricated support 602, an object may be first produced using flat layers, and then later produced using curved layers, without needing to change or generate a new support structure.
[0058]Various embodiments may be practiced within a system for designing and manufacturing 3D objects. Turning to FIG. 7, an example of a computer environment suitable for the implementation of 3D object design and manufacturing is shown. The environment includes a system 700. The system 700 includes one or more computers 702a-702d, which can be, for example, any workstation, server, or other computing device capable of processing information. In some aspects, each of the computers 702a-702d can be connected, by any suitable communications technology (e.g., an internet protocol), to a network 705 (e.g., the Internet). Accordingly, the computers 702a-702d may transmit and receive information (e.g., software, digital representations of 3-D objects, commands or instructions to operate an additive manufacturing device, etc.) between each other via the network 705.
[0059]The system 700 further includes one or more additive manufacturing devices (e.g., 3-D printers) 706a-706b. As shown the additive manufacturing device 706a is directly connected to a computer 702d (and through computer 702d connected to computers 702a-702c via the network 705) and additive manufacturing device 706b is connected to the computers 702a-702d via the network 705. Accordingly, one of skill in the art will understand that an additive manufacturing device 706 may be directly connected to a computer 702, connected to a computer 702 via a network 705, and/or connected to a computer 702 via another computer 702 and the network 705.
[0060]It should be noted that though the system 700 is described with respect to a network and one or more computers, the techniques described herein also apply to a single computer 702, which may be directly connected to an additive manufacturing device 706.
[0061]FIG. 8 illustrates a functional block diagram of one example of a computer of FIG. 7. The computer 702a includes a processor 810 in data communication with a memory 820, an input device 830, and an output device 840. In some embodiments, the processor is further in data communication with an optional network interface card 860. Although described separately, it is to be appreciated that functional blocks described with respect to the computer 802a need not be separate structural elements. For example, the processor 810 and memory 820 may be embodied in a single chip.
[0062]The processor 810 can be a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any suitable combination thereof designed to perform the functions described herein. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
[0063]The processor 810 can be coupled, via one or more buses, to read information from or write information to memory 820. The processor may additionally, or in the alternative, contain memory, such as processor registers. The memory 820 can include processor cache, including a multi-level hierarchical cache in which different levels have different capacities and access speeds. The memory 820 can also include random access memory (RAM), other volatile storage devices, or non-volatile storage devices. The storage can include hard drives, optical discs, such as compact discs (CDs) or digital video discs (DVDs), flash memory, floppy discs, magnetic tape, and Zip drives.
[0064]The processor 810 also may be coupled to an input device 830 and an output device 840 for, respectively, receiving input from and providing output to a user of the computer 702a. Suitable input devices include, but are not limited to, a keyboard, buttons, keys, switches, a pointing device, a mouse, a joystick, a remote control, an infrared detector, a bar code reader, a scanner, a video camera (possibly coupled with video processing software to, e.g., detect hand gestures or facial gestures), a motion detector, or a microphone (possibly coupled to audio processing software to, e.g., detect voice commands). Suitable output devices include, but are not limited to, visual output devices, including displays and printers, audio output devices, including speakers, headphones, earphones, and alarms, additive manufacturing devices, and haptic output devices.
[0065]The processor 810 further may be coupled to a network interface card 860. The network interface card 860 prepares data generated by the processor 810 for transmission via a network according to one or more data transmission protocols. The network interface card 860 also decodes data received via a network according to one or more data transmission protocols. The network interface card 860 can include a transmitter, receiver, or both. In other embodiments, the transmitter and receiver can be two separate components. The network interface card 860, can be embodied as a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any suitable combination thereof designed to perform the functions described herein.
[0066]FIG. 9 illustrates a process 900 for manufacturing a 3-D object or device. As shown, at step 905, a digital representation of the object is designed using a computer, such as the computer 702a. For example, 2-D or 3-D data may be input to the computer 702a for aiding in designing the digital representation of the 3-D object. Continuing at step 910, information is sent from the computer 702a to an additive manufacturing device, such as additive manufacturing device 706, and the device 706 commences the manufacturing process in accordance with the received information. At step 915, the additive manufacturing device 706 continues manufacturing the 3-D object using suitable materials, such as a liquid resin (for stereolithography applications, for example), powder (for sintering applications), thermoplastic (for fused deposition modelling), or some other suitable 3-D printing material. Further, at step 920, the 3-D object is generated.
[0067]These suitable materials may include, but are not limited to a photopolymer resin, polyurethane, methyl methacrylate-acrylonitrile-butadiene-styrene copolymer, resorbable materials such as polymer-ceramic composites, metal, metal alloy, etc. Examples of commercially available materials are: DSM Somos® series of materials 7100, 8100, 9100, 9420, 10100, 11100, 12110, 14120 and 15100 from DSM Somos; ABSplus-P430, ABSi, ABS-ESD7, ABS-M30, ABS-M30i, PC-ABS, PC ISO, PC, ULTEM 9085, PPSF and PPSU materials from Stratasys; Accura Plastic, DuraForm, CastForm, Laserform and VisiJet line of materials from 3D-Systems; the PA line of materials, PrimeCast and PrimePart materials and Alumide and CarbonMide from EOS GmbH, Aluminum, CobaltChrome and Stainless Steel materials, MarangingSteel, Nickel Alloy, and Titanium. The VisiJet line of materials from 3-Systems may include Visijet Flex, Visijet Tough, Visijet Clear, Visijet HiTemp, Visijet e-stone, Visijet Black, Visijet Jewel, Visijet FTI, etc. Examples of other materials may include Objet materials, such as Objet Fullcure, Objet Veroclear, Objet Digital Materials, Objet Duruswhite, Objet Tangoblack, Objet Tangoplus, Objet Tangoblackplus, etc. Another example of materials may include materials from the Renshape 5000 and 7800 series.
[0068]The embodiments described herein may be implemented using a fused deposition modelling (“FDM”) device. FIG. 10A is block diagram providing an example of an FDM device 1000 which may be used in connection with one or more embodiments. As shown, the FDM device 1000 includes a build platform 1002 which may be moveable along a Z-axis, driven by a Z-axis motor (not shown). The FDM device 1000 may also include a liquefier head 1004 which has one or more extrusion nozzles 1006. In this example, the liquefier head 1004 includes two extrusion nozzles 1006. The extrusion nozzles 1006 may be configured to extrude different materials—for example, a build material and a support material. The different extrusion nozzles may also be configured to extrude two different build materials. Some FDM devices 1000 may include more than two extrusion nozzles 1006. The liquefier head 1004 receives build and/or support material 1008 from one or more spools 1010. As stated above, the material may be a thermoplastic material. The material is spooled into the liquefier head 1004, where it is heated into a liquid or partially-liquid form and extruded through the extrusion nozzles 1006.
[0069]The extrusion nozzles may be driven by one or more motors (not shown) along the X-axis and Y-axis. Thus, the extrusion nozzles 1006 can be moved to the appropriate location over the build platform to deposit the build and/or support material 1008 in the appropriate location according to design of the part to be printed. In some implementations, the liquefier head (or liquefier heads) may be configured to also move along the Z-axis. In these implementations, build platform may remain stationary during the build process. The FDM device 1000 may also include a foam slab 1012 or some other base material that is placed on top of the build platform prior to beginning a build process. The foam slab is typically used to hold the object firmly in place while it is being printed. As shown in the example of FIG. 10A, an FDM device may print a part 1014 that includes support 1016. The part 1014 may be printed from one nozzle 1006 using the build material spool, while the supports 1016 may be printed from the other nozzle 1006 using the support material spool. In addition, the FDM device 1000 may also include multiple nozzles with build material, with each nozzle having a different build material with different material properties. Alternatively, the FDM device may be a single nozzle device in which the support is printed using a first material, and the build material is then changed out to print the object on top of the support.
[0070]Although the embodiments described herein are generally described in the context of fused deposition modelling printing, a skilled artisan will appreciate that other types of 3-D printing devices may be used to implement the inventions described herein. For example, various embodiments may be practiced using a stereolithography apparatus. FIG. 10B illustrates an exemplary stereolithography manufacturing apparatus 1020 for generating a three-dimensional (3-D) object. The stereolithography apparatus 1020 includes a reservoir 1022 that may hold a volume of liquid, such as a resin used to build the 3-D object. The stereolithography apparatus 1020 further includes a transport system 1024 that may be used to transport the liquid from the reservoir 1022 to an object coater head 1026. The transport system may include one or more tubes, pipes, or hoses configured to transport the liquid from the reservoir 1022. In some embodiments, the transport system 404 may include metal or plastic materials, such as ultra-high molecular weight polyethylene (UHMWPE), polyacrylate (PA), polyvinyl chloride (PVC), or any other suitable material. Although this particular example provides a stereolithography apparatus with a transport system, a skilled artisan will appreciate that other types of stereolithography apparatuses may not use a transport system to transport resin to a build platform. Rather, the build platform may instead be configured to sink into the reservoir during the building process.
[0071]The stereolithography apparatus 1020 may further include a guiding structure in the reservoir 1022 configured to guide a flow of the liquid from the reservoir 1022 to the transport system 1024. For example, the structure may include a series of tubes or plates that are placed to strategically direct the flow of the liquid to the transport system 1024. The apparatus 1020 also may include a building area where the liquid resin is deposited. The building area typically includes a building area support upon which the 3D object is built.
[0072]The stereolithography apparatus 1020 further includes a light source. The light source is typically included for the purpose of polymerizing the liquid to form a 3D object. The light source may take various forms. In some embodiments, the light source may be an electromagnetic light source, such as an ultra-violet (UV) light source, an infrared (IR) light source. In general, the light source may be any type of laser beam capable of solidifying the liquid.
[0073]In some implementations, the stereolithography apparatus 1020 may include at least one pump used to pump the liquid from the reservoir 1022 to the object coater head 1026. For example, a positive displacement pump and/or a centrifugal-type pump may be used. In some embodiments, the pump may include a filter unit to add further filtration to the liquid resin prior to being deposited to the building area. In some aspects, the pump may provide a defined flow (e.g., 0.5-40 liters/min) that may be fixed or regulated via an active feedback loop. For example, the feedback loop may be direct based upon flow measurements. As another example, the feedback may be indirect using measurements of the thickness of the layers being deposited in the additive manufacturing process.
[0074]The stereolithography apparatus 1020 may be used to generate one or more 3D objects layer by layer. The stereolithography machine 1020, for example, may utilize a liquid resin (e.g., a photopolymer resin) to build an object a layer at a time, such as by depositing the resin from the object coater head 1026 in the form of a curtain. In these implementations, the object coater head 1026 may