Patent Publication Number: US-2020290392-A1

Title: Printer device using acoustic levitation

Description:
TECHNICAL FIELD 
     The present disclosure relates to a printing apparatus using acoustic levitation. 
     BACKGROUND ART 
     3D printer technology is technology capable of fabricating complex structures in a short time by stacking layers corresponding to drawings made using computer-aided design (CAD) without cutting. Recently, beyond prototyping, this technology is being actively utilized in industries such as medical, automotive, ships, and footwear. 
     3D printers include a stereolithography apparatus (SLA) method using the principle in which, when a laser beam is irradiated to a photo-curing resin, a scanned portion is cured, a selective laser sintering (SLS) method using the principle in which, instead of a photo-curing resin, a functional polymer or metal powder is used in the SLA and is sintered and molded by irradiating a laser beam thereto, a fused deposition modeling (FDM) method, and a digital light processing (DLP) method using the principle in which light is irradiated to the lower portion of a reservoir in which a photo-curing resin is stored to partially cure the photo-curing resin. 
     With the development of such 3D printer technologies, the importance of technologies for improving the precision of an output is increasing. 
     DESCRIPTION OF EMBODIMENTS 
     Technical Problem 
     The present disclosure provides a printing apparatus for printing a target object by using acoustic levitation. 
     Solution to Problem 
     The present disclosure provides a printing apparatus using acoustic levitation, the printing apparatus including an acoustic levitation unit, which includes at least one acoustic wave generator and is configured to generate an acoustic field to levitate at least one printing material and form print layers having specific patterns; a material supply unit configured to supply the printing material; and a placing unit, which includes a plate, wherein the print layers are sequentially stacked on the plate. 
     Advantageous Effects of Disclosure 
     A printing apparatus using acoustic levitation according to embodiments of the present disclosure may form a printing material in a specific pattern while the printing material is being levitated by using acoustic waves. Therefore, the printing material may be precisely controlled, and thus a precise printing may be performed. Particularly, in a printing apparatus using acoustic levitation according to embodiments of the present disclosure, sensitive printing materials having viscoelasticity may be formed in specific patterns without physical contact, and thus a target object may be printed by using various materials. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a printing apparatus using acoustic levitation according to an embodiment of the present disclosure. 
         FIG. 2  is a partial cross-sectional view of the printing apparatus using the acoustic levitation of  FIG. 1 . 
         FIG. 3  is a block diagram showing the printing apparatus using the acoustic levitation of  FIG. 1 . 
         FIG. 4  is a schematic view of a portion of a printing apparatus using acoustic levitation according to another embodiment of the present disclosure. 
     
    
    
     BEST MODE 
     According to an aspect of the present disclosure, a printing apparatus using acoustic levitation, the printing apparatus includes an acoustic levitation unit, which includes at least one acoustic wave generator and is configured to generate an acoustic field to levitate at least one printing material and form print layers having specific patterns; a material supply unit configured to supply the printing material; and a placing unit, which includes a plate, wherein the print layers are sequentially stacked on the plate. 
     According to an embodiment of the present disclosure, the printing apparatus may further include a photo-curing unit configured to cure the print layers stacked on the plate by irradiating light toward a path in which the plate moves. 
     According to an embodiment of the present disclosure, the printing apparatus may further include a control unit configured to generate pattern information of the print layers according to a stacking order by using shape information regarding a target object to be fabricated and thickness information of the printing material and control the acoustic levitation unit to generate the acoustic field in correspondence to the pattern information. 
     According to an embodiment of the present disclosure, when the placing unit approaches within a pre-set distance or closer to the acoustic levitation unit, the control unit may drop the print layer by controlling the acoustic levitation unit. 
     According to an embodiment of the present disclosure, the printing apparatus may further include a vertical driving unit configured to move the plate up and down. 
     According to an embodiment of the present disclosure, the material supply unit may be provided adjacent to the acoustic levitation unit to supply the printing material toward the acoustic field. 
     According to an embodiment of the present disclosure, the material supply unit may be connected to the acoustic levitation unit and supplies the printing material to the acoustic levitation unit, and the acoustic levitation unit may simultaneously generate the acoustic field and supplies the printing material to the acoustic field. 
     According to another aspect of the present disclosure, a printing apparatus using acoustic levitation, the printing apparatus includes an acoustic levitation unit, which includes one or more acoustic wave generators and a planar driving unit configured to move the acoustic wave generators in at least one of a first direction and a second direction crossing the first direction and is configured to generate an acoustic field to levitate one or more printing materials; a placing unit including a plate on which the printing material is placed; and a control unit configured to control the acoustic levitation unit, such that the printing material is placed on the plate in correspondence to shape information regarding a target object to be fabricated. 
     According to an embodiment of the present disclosure, the control unit may generate pattern information of print layers according to a stacking order by using shape information regarding the target object to be fabricated and thickness information of the printing material and control the acoustic levitation unit to generate the acoustic field in correspondence to the pattern information or to move the acoustic wave generators. 
     According to an embodiment of the present disclosure, the printing apparatus may further include a material supply unit provided adjacent to the acoustic levitation unit and configured to supply the printing material toward the acoustic field. 
     According to an embodiment of the present disclosure, the printing apparatus may further include a material supply unit connected to the acoustic levitation unit to supply the printing material to the acoustic levitation unit, wherein the acoustic levitation unit may simultaneously generate the acoustic field and supply the printing material to the acoustic field. 
     According to an embodiment of the present disclosure, the printing apparatus may further include a photo-curing unit configured to cure the printing material stacked on the plate by irradiating light toward a path in which the plate moves. 
     According to an embodiment of the present disclosure, the printing apparatus may further include a vertical driving unit configured to move the plate up and down. 
     Other aspects, features, and advantages will become apparent from the following drawings, claims, and detailed description of the present disclosure. 
     Mode of Disclosure 
     The present disclosure may include various embodiments and modifications, and embodiments thereof will be illustrated in the drawings and will be described herein in detail. The effects and features of the present disclosure and the accompanying methods thereof will become apparent from the following description of the embodiments, taken in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments described below, and may be embodied in various modes. 
     Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. In the drawings, the same elements are denoted by the same reference numerals, and a repeated explanation thereof will not be given. 
     It will be understood that although the terms “first”, “second”, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These elements are only used to distinguish one element from another. 
     As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     It will be further understood that the terms “comprises” and/or “comprising” used herein specify the presence of stated features or components, but do not preclude the presence or addition of one or more other features or components. 
     It will be understood that when a layer, region, or component is referred to as being “formed on” another layer, region, or component, it can be directly or indirectly formed on the other layer, region, or component. That is, for example, intervening layers, regions, or components may be present. 
     Sizes of elements in the drawings may be exaggerated for convenience of explanation. In other words, since sizes and thicknesses of components in the drawings are arbitrarily illustrated for convenience of explanation, the following embodiments are not limited thereto. 
     When a certain embodiment may be implemented differently, a specific process order may be performed differently from the described order. For example, two consecutively described processes may be performed substantially at the same time or performed in an order opposite to the described order. 
     In the specification, when a film, region, or component is connected to another film, region, or component, the films, regions, or components may not only be directly connected, but may also be indirectly connected via an intervening film, region, or component therebetween. For example, when a film, region, component is electrically connected to another film, region, or component, the films, regions, or components may not only be directly electrically connected, but may also be indirectly electrically connected via an intervening film, region, or component therebetween. 
       FIG. 1  is a schematic view of a printing apparatus  10  using acoustic levitation according to an embodiment of the present disclosure,  FIG. 2  is a partial cross-sectional view of the printing apparatus  10  using acoustic levitation of  FIG. 1 , and  FIG. 3  is a block diagram of the printing apparatus  10  using acoustic levitation of  FIG. 1 . 
     Referring to  FIGS. 1 to 3 , the printing apparatus  10  using acoustic levitation according to an embodiment of the present disclosure may include an acoustic levitation unit  110 , a material supply unit  120 , a placing unit  130 , a photo-curing unit  140 , and a control unit  150 . 
     The acoustic levitation unit  110  includes one or more acoustic wave generators  111  and may create an acoustic field AF to levitate one or more printing materials d. The acoustic levitation unit  110  may include a planar driving unit (not shown) that moves the acoustic wave generator  111  in at least one of a first direction (y direction) and a second direction (x direction) crossing the first direction (y direction). 
     For example, the acoustic levitation unit  110  may include rails R 1  and R 2  that guide the acoustic wave generator  111  in the first direction (y direction), and the planar driving unit (not shown) may move the acoustic wave generator  111  along the rails R 1  and R 2 . Therefore, the acoustic levitation unit  110  may scan along the x-y plane by moving while the printing material d is being levitated, and thus a print layer having a particular pattern may be formed and placed on the placing unit  130  described below. 
     Levitation using acoustic waves is a technique for levitating a material in a medium by using the radiation pressure of acoustic waves in high-density acoustic waves in the medium. The acoustic levitation unit  110  may include a first acoustic levitation unit  110 A and a second acoustic levitation unit  1106  that are arranged to face each other. The first acoustic levitation unit  110 A and the second acoustic levitation unit  1106  may each include one or more acoustic wave generators  111 . Here, the acoustic wave generator  111  is a unit for generating acoustic waves and may be, for example, an ultrasonic transducer. 
     The first acoustic levitation unit  110 A and the second acoustic levitation unit  1108  include a plurality of acoustic wave generators  111  arranged at constant intervals as illustrated, and, by adjusting the emission intensity of acoustic waves from the acoustic wave generators  111 , may generate an acoustic field AF for levitating a printing material. The acoustic field AF generates radiation pressure, which is a pressure that levitates an object as acoustic waves generated by the plurality of acoustic wave generators  111  cross one another. The acoustic levitation unit  110  may control the emission intensity of acoustic waves generated by the plurality of acoustic wave generators  111  and generate the acoustic field AF, thereby forming printing materials d in a particular pattern while the printing materials d are being levitated. 
     The material supply unit  120  may supply the printing material d. In one embodiment, the material supply unit  120  may be provided adjacent to the acoustic levitation unit  110  and supply the printing material d toward the acoustic field AF. At this time, in one embodiment, the printing material d may include a photo-curing material including an acrylic group. The printing apparatus  10  using acoustic levitation according to an embodiment of the present disclosure may perform a printing process by photo-curing the printing material d that is levitated and patterned. However, the present disclosure is not necessarily limited thereto. In another embodiment, the printing material d may be cured by using heat or the printing material d may be cured by using both methods. 
     Meanwhile, the printing material d may include a polymer material having viscoelasticity. Polymer materials constituting a polymer solution may include at least one selected from a group including polypropylene, polyethylene, polystyrene, polyethylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, poly-m-phenylene terephthalate, poly-p-phenylene isofuratate, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, polyvinylidene chloride-acrylate copolymer, polyacrylonitrile, polyacrylonitrile-methacrylate copolymer, polycarbonate, polyarylate, polyester carbonate, nylon, aramid, polycaprolactone, polylactic acid, polyglycolic acid, collagen, polyhydroxybutyric acid, polyvinyl acetate, and polypeptide, but the present disclosure is not limited thereto. In another embodiment, the printing material d may include metal powders used for  3 -dimensional printing. 
     In another embodiment, the material supply unit  120  may be connected to the acoustic levitation unit  110  and supply the printing material d to the acoustic levitation unit  110 . The material supply unit  120  may include a storage unit  121  for storing the printing material d and a supply tube  123  for guiding the printing material d from the storage unit  121  to the acoustic levitation unit  110 . 
     At this time, the acoustic levitation unit  110  may generate the acoustic field AF and supply the printing material d to the acoustic field AF simultaneously. For example, although not shown, the acoustic levitation unit  110  may include an accommodating portion for accommodating the printing material d supplied from the material supply unit  120  and a dispenser for supplying a certain amount of the printing material d from the accommodating portion to the acoustic field AF. As illustrated, a hole h may be formed at the center of the acoustic wave generator  111 , and the dispenser may supply a certain amount of the printing material d to the acoustic field AF through the hole h. 
     The placing unit  130  includes a plate  131  located under the acoustic levitation unit  110 , and the printing material d may be stacked on the plate  131 . The placing unit  130  further includes a vertical driving unit  133  that moves the plate  131  up and down, and thus the plate  131  may be moved reciprocally toward the acoustic levitation unit  110 . The printing material d may be levitated at a specific position by the acoustic levitation unit  110  and then placed on the plate  131 . The specific position described above may be determined based on shape information of a target object to be fabricated, and a print layer M 1  corresponding to the shape information of the target object may be formed on the plate  131 . 
     Meanwhile, the placing unit  130  may further include a heat supply unit (not shown) for supplying heat to the printing material d stacked on the plate  131 . In an embodiment of the present disclosure, in case of printing by using a heat-curable printing material d, the printing material d may be stacked on the plate  131  and cured simultaneously by supplying heat to the printing material d through the heat supply unit (not shown). 
     On the other hand, in the case of using a printing material d including a photo-curing material, the printing apparatus  10  using acoustic levitation according to an embodiment of the present disclosure may include the photo-curing unit  140 . The photo-curing unit  140  may cure the printing material d placed on the plate  131  or the above-described print layer M 1  by irradiating light toward a path in which the plate  131  moves. The photo-curing unit  140  may include, for example, one or more UV lamps. The UV lamps may be, as illustrated, arranged at a constant interval on a path in which the plate  131  moves up and down. 
     The control unit  150  may store shape information of a target object to be fabricated. The shape information of the target object to be fabricated may be provided by using an external device, such as a laser scanning device. The control unit  150  may control the acoustic levitation unit  110 , such that the printing material d is placed on the plate  131  of the placing unit  130  in correspondence to the shape information of the target object to be fabricated. 
     In detail, the control unit  150  may generate pattern information of the print layer M 1  according to a stacking order by using information regarding the thickness of the printing material d known in advance and the shape information. The control unit  150  divides the target object into a plurality of print layers M 1  in the heightwise direction (z direction) in correspondence to the thickness of the printing material d and then generates pattern information of each print layer M 1 . The control unit  150  may control the acoustic levitation unit  110 , such that the printing material d levitated by the acoustic levitation unit  110  may be positioned in correspondence to the above-described pattern information of the print layers M 1 . In other words, the control unit  150  may control the acoustic levitation unit  110  to generate the acoustic field AF corresponding to the pattern information or move the acoustic wave generator in the first direction (y direction) or the second direction (x direction). 
     Also, the control unit  150  may control the placing unit  130 , such that the printing material d levitated by the acoustic levitation unit  110  may be placed on the plate  131 . When one print layer M 1  is formed on the plate  131  by the acoustic levitation unit  110 , the control unit  150  may control the vertical driving unit  133  to move the plate  131  away from the acoustic levitation unit  110 . The control unit  150  controls the photo-curing unit  140  while the plate  131  is moving, thereby curing the print layer M 1  by irradiating light to the print layer M 1  formed on the plate  131 . 
     Then, the control unit  150  moves the plate  131  toward the acoustic levitation unit  110  again and controls the vertical driving unit  133 , such that a new print layer M 1  is placed on the cured print layer M 1 . The target object may be completed by repeating the above-stated operations. 
       FIG. 4  is a schematic view of a portion of a printing apparatus  10 - 1  using acoustic levitation according to another embodiment of the present disclosure. The printing apparatus  10 - 1  using acoustic levitation according to another embodiment is the same as the printing apparatus  10  using acoustic levitation according to the previous embodiment, except for the acoustic levitation unit  110  and the control unit  150 . Therefore, descriptions identical to those already given above will be omitted. 
     Referring to  FIGS. 3 and 4 , the printing apparatus  10 - 1  using acoustic levitation according to another embodiment of the present disclosure may include the acoustic levitation unit  110 , the material supply unit  120 , the placing unit  130 , the photo-curing unit  140 , and the control unit  150 . 
     The acoustic levitation unit  110  includes one or more acoustic wave generators  111  and may generate the acoustic field AF to levitate one or more printing materials d to form the print layer M 1  having a specific pattern. At this time, unlike in the previous embodiment, the acoustic levitation unit  110  according to another embodiment forms a plurality of printing materials d into one print layer and placing the print layer on the placing unit  130 , instead of scanning and printing the printing material d. 
     The acoustic levitation unit  110  includes a plurality of acoustic wave generators  111  and, as illustrated, may be arranged to surround the printing material d. The acoustic levitation unit  110  each includes a plurality of acoustic wave generators  111  arranged at a constant interval and, by controlling the emission intensity of acoustic waves from the acoustic wave generators  111 , may generate the acoustic field AF for levitating the printing material d. The acoustic levitation unit  110  according to another embodiment may form the plurality of printing materials d into the print layer M 1  including a specific pattern and levitate the same through the plurality of acoustic wave generators  111  arranged therearound. 
     The material supply unit  120  may supply the printing material d. In one embodiment, the material supply unit  120  may be provided adjacent to the acoustic levitation unit  110  and supply a printing material (the printing material d?) toward the acoustic field AF. In another embodiment, the material supply unit  120  may be connected to the acoustic levitation unit  110  and supply the printing material d to the acoustic levitation unit  110 . 
     The placing unit  130  includes a plate  131  located under the acoustic levitation unit  110 , and the print layer M 1  may be stacked on the plate  131 . The print layers M 1  may be sequentially stacked to form a target object M 0  to be fabricated. The placing unit  130  further includes a vertical driving unit  133  that moves the plate  131  up and down, and thus the plate  131  may be moved reciprocally toward the acoustic levitation unit  110 . 
     The control unit  150  may generate pattern information of the print layer M 1  according to a stacking order by using shape information of the target object M 0  to be fabricated and information regarding the thickness of the printing material d. The control unit  150  may control the acoustic levitation unit  110  to generate the acoustic field AF in correspondence to the pattern information. 
     At this time, the control unit  150  may drop the print layer M 1  by controlling the acoustic levitation unit  110  when the placing unit  130  approaches within a pre-set distance or closer to the acoustic levitation unit  110 . In other words, the printing apparatus  10 - 1  using acoustic levitation according to another embodiment of the present disclosure may generate the acoustic field AF to form the print layers M 1  having specific patterns and sequentially dropping and placing the print layers M 1  on the placing unit  130 , thereby completing the target object M 0 . 
     When the print layer M 1 , which is levitated by the acoustic levitation unit  110 , is dropped and placed on the plate  131 , the control unit  150  may control the vertical driving unit  133  to move the plate  131  away from the acoustic levitation unit  110 . The control unit  150  controls the photo-curing unit  140  while the plate  131  is moving, thereby curing the print layer M 1  by irradiating light to the print layer M 1  formed on the plate  131 . The control unit  150  may complete the target object M 0  by repeating the above-stated operations. 
     As described above, a printing apparatus using acoustic levitation according to embodiments of the present disclosure may form a printing material in a specific pattern while the printing material is being levitated by using acoustic waves. Therefore, the printing material may be precisely controlled, and thus a precise printing may be performed. Particularly, in a printing apparatus using acoustic levitation according to embodiments of the present disclosure, sensitive printing materials having viscoelasticity may be formed in specific patterns without physical contact, and thus a target object may be printed by using various materials. 
     While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the present disclosure is not limited to the disclosed example embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of protection of the present disclosure should be determined by the technical idea of the appended claims. 
     INDUSTRIAL APPLICABILITY 
     According to an embodiment of the present disclosure, a printing apparatus using acoustic levitation effect is provided. Also, embodiments of the present disclosure may be applied to industrial 3D printing apparatuses.