Patent Publication Number: US-2023158742-A1

Title: High speed additive manufacturing apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of Taiwanese Patent Application No. 110143089 filed on Nov. 19, 2021, the contents of which are incorporated herein by reference in their entirety. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to an additive manufacturing apparatus, and more particularly to a high-speed additive manufacturing apparatus including a two-dimensional array of light sources having unaligned arrangement in adjacent rows for performing a high-speed additive manufacturing process. 
     Description of the Related Art 
     An additive manufacturing technology (also named three-dimensional printing) is a process that includes the following steps: constructing a three-dimensional model of a product, dividing the three-dimensional model into multiple horizontal layers, and forming the product layer by layer according to the designed horizontal layers of the three-dimensional model. A product having complicated shape or high manufacturing cost produced by traditional processing methods can be manufactured by the additive manufacturing technology. Therefore, the additive manufacturing technology has been highly valued by industrial enterprises in recent years. 
     The additive manufacturing technology mainly includes seven kinds of processes, the fused deposition modeling (FDM), the vat photopolymerization (SLA, DLP), the powder bed fusion (SLS, DMLS), the binder jetting (3DPG), the material jetting, the laminated object manufacturing (LOM), and the direct energy deposition (DED), wherein the powder bed fusion process utilizes laser beam being spotted on raw material in a powder bed, which is also named laser sintering method including selective laser sintering (SLS) and direct metal laser sintering (DMLS). The raw material of powder is molten by the laser beam and then solidified to form the designed shape of one layer. As the product is formed layer by layer in the powder bed, the powdery raw material provides support for the half-made product during the additive manufacturing process, and thus no support structure is needed to be designed for the three-dimensional model of the product, and thus the accomplished product has a higher strength. For the reasons above, people pay more and more attentions to the application of the additive manufacturing technology. 
     The conventional laser sintering method for powdery raw material uses a single laser source for sintering process, wherein the single laser source moves along a predetermined path for sintering the powdery raw material in the powder bed to form the product layer by layer. However, such a process sintering the raw material with a single laser source has a very low formation rate, and the production capability is thus considerably limited. 
     BRIEF SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a high-speed additive manufacturing apparatus including a two-dimensional array of sintering light source assemblies which moves and sinters the raw material to construct designed layers of the product at a high forming rate, thereby solving the problem of low formation rate caused by utilization of a single laser source in the conventional laser powder sintering method. 
     The invention provides a high-speed additive manufacturing apparatus. The high-speed additive manufacturing apparatus in accordance with an exemplary embodiment of the invention includes a main body including a printing tank and a raw material tank adjacent to the printing tank; a sintering module including a plurality of sintering light source assemblies, wherein each of the sintering light source assemblies has a light beam emitting end disposed in the main body, the light beam emitting end emits a sintering light beam, the light beam emitting end is configured to move above the printing tank along a first direction, the light beam emitting ends of the sintering light source assemblies are arranged in a plurality of rows oriented along a second direction perpendicular to the first direction, and each of the light beam emitting ends in one row is unaligned with the light beam emitting ends in adjacent rows in the first direction; a product carrying member disposed in the printing tank, wherein a product is formed on the product carrying member, and the product carrying member is configured to move along a third direction in the printing tank; a raw material carrying member disposed in the raw material tank, wherein the raw material carrying member is configured to move along the third direction in the raw material tank; and a raw material wiper configured to move in the printing tank and the raw material tank. 
     In another exemplary embodiment, each of the sintering light source assemblies includes a light emitting member, a light beam guiding member and an optical collimator disposed at the light beam emitting end, the light emitting member emits a light guided by the light beam guiding member to pass through the optical collimator so as to form the sintering light beam. 
     In yet another exemplary embodiment, each of the sintering light source assemblies further includes an adapter, the light beam guiding member includes a first guiding section connected to the light emitting member at one end, and a second guiding section connected to the optical collimator at one end, the first guiding section is connected to the adapter at the other end, and the second guiding section is connected to the adapter at the other end. 
     In another exemplary embodiment, the sintering module further includes a collimator holder parallel to the product carrying member, the collimator holder has a plurality of first positioning holes in which the optical collimators are disposed respectively, the first positioning holes are arranged in a plurality of rows, and each of the first positioning holes in one row is unaligned with the first positioning holes in adjacent rows in the first direction. 
     In yet another exemplary embodiment, the sintering module further includes a guiding member holder having a plurality of second positioning holes, each of the second positioning holes corresponds to a plurality of the first positioning holes, and each of the second positioning holes accommodates a plurality of light beam guiding members. 
     In another exemplary embodiment, the guiding member holder is disposed above the collimator holder, the guiding member holder includes a plurality of securing plates correspondingly disposed in the second positioning holes, the sintering module further includes a plurality of bundling members corresponding to the second positioning holes, a plurality of the light beam guiding members are bundled by one of the bundling members and disposed in one of the second positioning holes, and each of the securing plates secures one of the bundling members in one of the second positioning holes. 
     In yet another exemplary embodiment, the sintering module further includes a movable seat configured to move along the first direction on the main body, the collimator holder and the guiding member holder are disposed on the movable seat, the movable seat has a light-passing opening corresponding to the first positioning holes, and the raw material wiper is disposed on one side of the movable seat. 
     In another exemplary embodiment, the high-speed additive manufacturing apparatus further includes a control module, wherein the control module includes a controller, a plurality of converters and a plurality of driving circuits, the controller has a plurality of input-output ports, the converters are connected to the input-output ports and the driving circuits, the driving circuits drive the light emitting members, the controller outputs control signals through the input-output ports according to a timing scheme, and the control signals are converted to driving signals transmitted to the driving circuits to drive the light emitting members. 
     In yet another exemplary embodiment, the control signals are digital signals, and the driving signals are pulse width modulation signals. 
     In another exemplary embodiment, the high-speed additive manufacturing apparatus further includes a position detector disposed in the main body and configured to detect a position of the light beam emitting end and generate a detecting signal transmitted to the controller, the controller generates the control signals according to the detecting signal. 
     The high-speed additive manufacturing apparatus of the present invention includes a two-dimensional array of sintering light source assemblies of which the light beam emitting ends in adjacent rows are unaligned, and the light beam emitting ends can scan multiple linear regions constituting one designed layer. After the two-dimensional array of the light beam emitting ends of the sintering module moves along the first direction only in one stroke, one designed layer of the product is accomplished. Therefore, the product is manufactured by the high-speed additive manufacturing apparatus of the present invention at a very high forming rate. 
     A detailed description is given in the following embodiments with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
         FIG.  1    is a perspective view of an embodiment of a high-speed additive manufacturing apparatus of the present invention; 
         FIG.  2    is a perspective view of a portion of the high-speed additive manufacturing apparatus of  FIG.  1   ; 
         FIG.  3    is a top view of  FIG.  2   ; 
         FIG.  4    is a perspective view of a portion of a sintering module of the high-speed additive manufacturing apparatus of the present invention; 
         FIG.  5    is a schematic view of a light beam emitting end of the sintering module; 
         FIGS.  6  to  8    are schematic views of the light beam emitting end of the sintering module performing a sintering process for raw material; 
         FIG.  9    is a schematic view of a sintering light source assembly of the high-speed additive manufacturing apparatus of the present invention; 
         FIG.  10    is perspective view of a collimator holder and a guiding member holder disposed on a movable seat of the high-speed additive manufacturing apparatus of the present invention; 
         FIG.  11    is a schematic view of the collimator holder and the collimators equipped thereon of the high-speed additive manufacturing apparatus of the present invention; 
         FIG.  12    is a top view of  FIG.  11   ; and 
         FIG.  13    is a schematic view of a controller of the high-speed additive manufacturing apparatus of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims. 
     Referring to  FIGS.  1 ,  2 ,  3  and  4   , an embodiment of a high-speed additive manufacturing apparatus of the present invention is disclosed. The high-speed additive manufacturing apparatus of the present embodiment includes a main body  10  and a movable seat  20 . The main body  10  includes a printing tank  11  and a raw material tank  12  adjacent to the printing tank  11 . The printing tank  11  and the raw material tank  12  are disposed on an operation surface of a top portion of the main body  10 . Powdery raw material, such as plastic powder or metal powder, is stored in the raw material tank  12 . The movable seat  20  is disposed on the operation surface, and configured to move above the printing tank  11  and the raw material tank  12  along a first direction X through a first servo motor  21 . 
     The high-speed additive manufacturing apparatus of the present embodiment further includes a product carrying member  30  and a raw material carrying member  40 . The product carrying member  30  is disposed in the printing tank  11  and constitute a bottom of the printing tank  11 . The product carrying member  30  is moved along a third direction Z by a second servo motor  31  disposed on a bottom of the main body  10 . The raw material carrying member  40  is disposed in the raw material tank  12  and constitute a bottom of the raw material tank  12 . The raw material carrying member  40  is moved along the third direction Z by a third servo motor  41  disposed on a bottom of the main body  10 . The product carrying member  30  and the raw material carrying member  40  are moved in opposite directions during the additive manufacturing process. The product carrying member  30  moves downwards (in the −Z direction) as the product is formed layer by layer, whereby the powdery raw material can be supplied to spread on the printing tank  11  layer by layer. The raw material carrying member  40  move upwards (in the +Z direction) for the supplement of the powdery raw material to the printing tank  11 . The high-speed additive manufacturing apparatus of the present embodiment further includes a raw material wiper  50  disposed on the movable seat  20 . The raw material wiper  50  is exemplarily a powder roller disposed at one side of the movable seat  20  and moved with the movable seat  20 . The raw material wiper  50  is disposed on the right side of the movable seat  20 . The movable seat  20  moves across the raw material tank  12  and the printing tank  11  sequentially from the left side of raw material tank  12 , whereby the raw material wiper  50  moves across the raw material tank  12  and the printing tank  11  sequentially along with the movable seat  20  to spread the powdery raw material to the printing tank  11  from the raw material tank  12 . 
     The high-speed additive manufacturing apparatus of the present embodiment further includes a sintering module  60 . The sintering module  60  includes a plurality of sintering light source assemblies  61 . Each of the sintering light source assemblies  61  includes a light beam emitting end  611  disposed on the movable seat  20  and located on the right side of the raw material wiper  50 . The light beam emitting end  611  is moved with the movable seat  20  above the printing tank  11  along the first direction X. When the movable seat  20  moves from left to right, the raw material wiper  50  pushes the powdery raw material from the raw material tank  12  into the printing tank  11 , and afterwards the light beam emitting end  611  moves thereacross and scans the printing tank  11 . The light beam emitting end  611  emits a sintering light beam. The sintering light beam passes through a light-passing opening  22  formed on the movable seat  20  (referring to  FIG.  10   ) and spots on the raw material spread on the printing tank  11 . The raw material is molten by the sintering light beam and then solidified to form the designed layer of the product. 
     Referring to  FIGS.  5 ,  6 ,  7  and  8   , the light beam emitting ends  611  of the sintering light source assemblies  61  are arranged in a plurality of rows oriented along a second direction Y perpendicular to the first direction X. Each light beam emitting end  611  in one row is unaligned with the light beam emitting ends  611  in adjacent rows in the first direction X. The two-dimensional array of the light beam emitting ends  611  moves along the first direction X during the additive manufacturing process. As shown in  FIG.  6   , when the first row of the light beam emitting ends  611  passes through a one-dimensional printing region oriented in the second direction Y, the laser beam from light beam emitting ends  611  sinters the raw material in some specific positions, whereby a shaped region A is formed. Afterwards, as shown in  FIG.  7   , when the second row of the light beam emitting ends  611  passes through the same one-dimensional printing region, the laser beam from the light beam emitting ends  611  sinters the raw material in other specific positions, whereby a shaped region B is formed. Similarly, as shown in  FIG.  8   , when the third row of the light beam emitting ends  611  passes through the same one-dimensional printing region, the laser beam from the light beam emitting ends  611  sinters the raw material in yet other positions, whereby a shaped region C is formed. Therefore, as the three rows of the light beam emitting ends  611  forms the shaped regions A, B and C, a desired shape constituted by the shaped regions A, B and C oriented in the second direction Y is formed. In this way, when the two-dimensional array of the light beam emitting ends  611  moves along the first direction X, a desired shape of a layer is formed by combination of multiple shapes formed in multiple one-dimensional printing regions oriented in the second direction Y. Therefore, the two-dimensional array of the light beam emitting ends  611  moves in one stroke can completely form the whole structure of one layer of the product, thereby realizing an additive manufacturing process of high forming rate. The two-dimensional array of the light beam emitting ends  611  includes hundreds of light beam emitting ends  611 . The structure of the light source assembly  61  and the structure for securing the light source assembly  61  to the sintering module  60  is described as follows. 
     Referring to  FIG.  9   , an embodiment of the light source assembly  61  of the sintering module  60  is disclosed. Each light source assembly  61  includes a light emitting member  612 , a light beam guiding member  613  and an optical collimator  614 . The optical collimator  614  is disposed at the light beam emitting end  611 . The light emitting member  612  emits a light, and the emitted light is guided by the light beam guiding member  613  to pass through the optical collimator  614  so as to form the sintering light beam. The light emitting member  612  of the present embodiment is a laser diode, the light beam guiding member  613  of the present embodiment is an optical fiber, and the optical collimator  614  includes a lens set. Each light source assembly  61  further includes an adapter  615 . The light beam guiding member  613  includes a first guiding section  6131  and a second guiding section  6132 . The first guiding section  6131  is connected to the light emitting member  612  at one end, and the second guiding section  6132  is connected to the optical collimator  614  at one end. The first guiding section  6131  is connected to the adapter  615  through a connector at the other end, and the second guiding section  6132  is also connected to the adapter  615  through a connector at the other end. The connector is exemplarily a FC/PC connector. The first guiding section  6131  and the second guiding section  6132  is connected to the adapter  615  through FC/PC connectors. As the light beam guiding member  613  is constituted by the first guiding section  6131  and the second guiding section  6132 , the part related to the light emitting member  612  (the first guiding section  6131 ) or the part related to the optical collimator  614  (the second guiding section  6132 ) is selectively replaced depending on the maintenance condition. It is not necessary to replace the entire light beam guiding member  613  as what is done for the conventional equipment, thereby reducing the maintenance cost. 
     Referring to  FIGS.  10 ,  11  and  12   , the sintering module  60  further includes a collimator holder  62  which is plate-shaped, disposed in the movable seat  20  and parallel with the product carrying member  30 . The collimator holder  62  has a plurality of first positioning holes  621  in which the optical collimators  614  are disposed respectively. The first positioning holes  621  correspond to the light-passing opening  22  of the movable seat  20 , whereby the sintering light beam passes through the light-passing opening  22  and spots on the powdery raw material in the printing tank  11 . The first positioning holes  621  are arranged in a plurality of rows to constitute a two-dimensional array. Each first positioning hole  621  in one row is unaligned with the first positioning holes  621  in adjacent rows along the first direction X, whereby the optical collimators  614  are arranged in a manner that each optical collimator  614  in one row is unaligned with the optical collimators  614  in other rows along the first direction X. 
     The sintering module  60  further includes a guiding member holder  63  disposed on the movable seat  20  and located above the collimator holder  62 . The guiding member holder  63  has a plurality of second positioning holes  631 . One second positioning hole  631  corresponds to a plurality of first positioning holes  621 . A plurality of the light beam guiding members  612  connected to a plurality of the optical collimators  614  are collectively accommodated in one second positioning hole  631 . Therefore, each second positioning hole  631  accommodates a plurality of the light beam guiding members  612 . In the present embodiment, each second positioning hole  631  accommodates eight pieces of the light beam guiding member  612 . Moreover, the sintering module  60  further includes a plurality of bundling members  64 . Each bundling member  64  bundles a plurality of light beam guiding members  613  in one second positioning hole  631 . The guiding member holder  63  further includes a plurality of securing plates  632 . Slots  633  are formed on opposite inner walls of each second positioning hole  631 , and the securing plate  632  is inserted into the slots  633 , whereby the securing plate  632  and the inner walls of the second positioning hole  631  hold the bundling member  64  to secure the bundling member  64  in the second positioning hole  631 . 
     The sintering module  60  further includes an assistant holder  65  disposed above the collimator holder  62  and located between the collimator holder  62  and the guiding member holder  63 . The assistant holder  65  has a plurality of third positioning holes  651  aligned with the first positioning holes  621 . The end of the optical collimator  614  connected to the light beam guiding member  613  is disposed in the third positioning hole  651 , whereby the optical collimator  614  is positioned in the collimator holder  62  and the assistant holder  65 . 
     Referring to  FIG.  13   , the high-speed additive manufacturing apparatus of the present embodiment further includes a control module  70 . The control module  70  includes a controller  71 , a plurality of converters  72  and a plurality of driving circuits  73 . The controller  71  has a plurality of input-output ports, and the converters  72  are connected to the input-output ports and the driving circuits  73 . The driving circuits  73  drive the light emitting members  612 . The controller  71  of the present embodiment is the digital output module R1-EC70X2 produced by Delta Electronics. Inc., which has thirty-two input-output ports. The controller  71  outputs control signals through the input-output ports according to a timing scheme. The control signals are converted to driving signals by the converters  72 . The driving signals are transmitted to the driving circuits  73  to drive the light emitting members  612 . The converter  72  of the present embodiment is the chip of Tamega 2560, which converts the digital control signals from the controller  71  to pulse width modulation (PWM) signals, thereby driving the light emitting member  612 . 
     Referring to  FIG.  4    again, the high-speed additive manufacturing apparatus of the present embodiment further includes a position detector  80  disposed on the main body  10  and the movable seat  20 . The position detector  80  is configured to detect the position of the movable seat  20  (light beam emitting end  611 ) and generate a detecting signal which is transmitted to the controller  71 . The controller  71  generates the control signal according to the detecting signal, i.e. the controller  71  generates the control signals to control light intensity of the light emitting members  612  according to the position of the movable seat  20  detected by the position detector  80 . The position detector  80  of the present embodiment is an optical ruler. 
     The high-speed additive manufacturing apparatus of the present embodiment further includes a human-machine interface including a stepping mode and a moving mode. The human-machine interface is executed by application program installed in the apparatus and displayed on a display device. A user can input operation parameters through the human-machine interface, such as the moving speeds and displacements of the movable seat  20 , the product carrying member  30  and the raw material carrying member  40  in each stroke. 
     The high-speed additive manufacturing apparatus of the present invention includes a two-dimensional array of sintering light source assemblies of which the light beam emitting ends in adjacent rows are unaligned, and the light beam emitting ends can scan multiple linear regions constituting one designed layer. After the two-dimensional array of the light beam emitting ends of the sintering module moves along the first direction only in one stroke, one designed layer of the product is accomplished. Therefore, the product is manufactured by the high-speed additive manufacturing apparatus of the present invention at a very high forming rate. 
     While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.