Abstract:
Various embodiments regarding systems and mechanisms for 3D printer and scanner devices. In accordance with an example embodiment, there is provided a print head assembly for a 3D printer which uses filament, including: a print head; a motor drive to control flow of the filament through the print head; and at least two idlers to provide traction between the motor drive gear and the filament.

Description:
CROSS-REFERENCE 
       [0001]    This application claims the benefit of the filing date of U.S. Provisional Patent Application Ser. No. 62/096,335 filed Dec. 23, 2014 entitled 3D PRINTER AND SCANNER MECHANISMS, the contents of which are hereby expressly incorporated by reference into the Detailed Description of the Drawings herein below. 
     
    
     FIELD 
       [0002]    The present application describes various embodiments regarding systems and mechanisms for 3D printer and scanner devices. 
       BACKGROUND 
       [0003]    It is desirable to reduce unwanted printer head movement. Unwanted printer head movement can result in parts with incorrect geometry and poor surface finish. Unwanted printer head movement reduces the accuracy of the printer. 
         [0004]    Other difficulties with existing systems, methods and techniques may be appreciated in view of the Detailed Description of the Drawings herein below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    Embodiments will now be described by way of examples with reference to the accompanying drawings, in which like reference numerals are used to indicate similar features, and in which: 
           [0006]      FIG. 1 a    shows an isometric view of 3D printer  1 . 
           [0007]      FIG. 1 b    shows front view of 3D printer  1 . 
           [0008]      FIG. 1 c    shows a detail view from  FIG. 1   b.    
           [0009]      FIG. 2  shows a front view of prior art filament motor drive. 
           [0010]      FIG. 3  is a section view from  FIG. 1   b.    
           [0011]      FIG. 4  is a detail view from  FIG. 1   b.    
           [0012]      FIG. 5 a    is an isometric view of 3D printer  1  showing roller bearings  27  with some components hidden. 
           [0013]      FIG. 5 b    is a front view of the assembly shown in  FIG. 5   a.    
           [0014]      FIG. 5 c    is a section from  FIG. 5   b.    
           [0015]      FIG. 6 a    is an isometric view of 3D printer  1  with some components hidden. 
           [0016]      FIG. 6 b    is a front view of 3D printer  1  shown in  FIG. 6   a.    
           [0017]      FIG. 6 c    is a side view of 3D printer  1  shown in  FIG. 6   a.    
           [0018]      FIG. 7 a    is an isometric view of the assembly shown in  FIG. 6 a    with XZ axis assembly  43  disengaged from elevator brackets  55 . 
           [0019]      FIG. 7 b    is a detail view from  FIG. 7   a.    
           [0020]      FIG. 8 a    is a rear top isometric view of XZ axis assembly  43  with some components hidden. 
           [0021]      FIG. 8 b    is a rear bottom isometric view of the assembly shown in  FIG. 8   a.    
           [0022]      FIG. 8 c    is a bottom view of XZ axis assembly  43 . 
           [0023]      FIG. 9 a    is a rear top isometric view of XZ axis assembly  43  with plates hidden. 
           [0024]      FIG. 9 b    is a rear view of the assembly shown in  FIG. 9   a.    
           [0025]      FIG. 9 c    is a section view from  FIG. 9   b.    
           [0026]      FIG. 10 a    is a rear isometric view of 3D printer  1  with the spool and spool tray hidden. 
           [0027]      FIG. 10 b    is a detail view from  FIG. 10   a.    
           [0028]      FIG. 10 c    is a top view of 3D printer  1  shown in  FIG. 10   a.    
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]      FIGS. 1 a -1 c    show 3D printer  1 . Print head assembly  3  is mounted on filament motor  5 . Print head assembly  3  has twin idlers  7  to provide traction of motor drive gear  9  on filament  11 . Print head assembly  3  has drive gear  9  and two idlers  7 . The presence of two idlers  7  applying pressure, via clutch  13  with springs  15 , onto filament  11  causes filament to bend around drive gear  9 , increasing the surface contact area, and increasing the traction on filament  11  being pushed into nozzle  17 . 
         [0030]    The print head shown in these drawings may be replaced with a laser, mill or other tool. 
         [0031]      FIG. 2  shows a prior art filament motor drive gear  19  with single idler  21 . The configuration relies on one tangential location of contact due to the normal force applied by the single idler  21  onto filament  11 , thereby reducing the traction on filament  11  being pushed into the nozzle. 
         [0032]      FIG. 3  is a section view from  FIG. 1 b   . Printer head assembly  3  width is limited to the width of filament motor  5 . No part of printer head assembly  3  extends beyond the vertical sides of filament motor  5 . Prior art printers have not limited the width of the printer head assembly. Prior art printer head assemblies often have components that extend to the left or right of the motor—filament clutch levers and cooling fans often exceed the width motor. Clutch button  21 , nor fan, nor drive idlers  7  extend beyond the motor  5  width unlike other 3D printers. By limiting the width of the printer head assembly  3  to the width of the filament motor  5 , for a given width of structure  23  the range of motion of the print head assembly is maximized—there are no components that extend to hit the structure  23  or other internal components  25  and limit the range of motion. This feature increases the ratio of build area to printer footprint which is advantageous for the user who can produce bigger parts while taking up less desk space compared to the competition. Similarly the volume of the printer is minimized for a given print area which is advantageous for storage and shipping. 
         [0033]      FIG. 4  is a detail view from  FIG. 1 b    showing roller bearing  27  supporting build platform  29  at the outer extremity.  FIGS. 5 a -5 c    show 3D printer  1  and roller bearings  27  (build platform  29  and YZ axis coverplates are hidden for clarity). Build platform  29  is supported by Y rail linear bearing mounting plate  31  and two roller bearings  27 , one on either side. Y rail  33  and roller bearings  27  are mounted to YZ axis assembly plate  35 . Roller bearings  27  serve to reduce deflection of build platform  29  on either side of the Y rail  33 . This additional support allows build platform  29  to have less structure and be lighter weight. Bearings  27  are mounted directly below the line of travel  37  of extrusion nozzle  17  where it is most important to limit deflection and produce a higher quality part. 
         [0034]      FIGS. 6 a -6 c    show 3D printer  1  with shell housing and Z motor mount brackets removed for clarity. 3D printer  1  has four linear bearings  39  traveling on four bearing rods  41  for vertical travel of XZ axis assembly  43  including print head assembly  3 . Z motors  45  drive lead screws  47  via nuts  46  and control vertical travel of the XZ axis assembly  43 . Y motor  49  drives belt  51  which drives linear bearing  53 , mounting plate  31  and build platform  29  riding on Y rail  33 . 
         [0035]      FIG. 7 a -7 b    show 3D printer  1  with XZ axis assembly  43  disengaged from elevator brackets  55 .  FIGS. 8 a -8 c    show XZ axis assembly  43  with CPU enclosure and circuit boards removed for clarity. XZ axis assembly  43  is removable from elevator brackets  55  and printer  1  without tools. First, ribbon cable (not shown) is removed from XZ axis assembly  43  ports  57 . By reaching beneath XZ axis assembly plate  59  with fingers, aircraft cable actuator  61  is tensioned to release the assembly  43 . Aircraft cable  61  is strung between spring loaded pins  63 . By pulling aircraft cable  61 , spring loaded pins  63  retract from holes  65  in plates  69  of elevator brackets  55 . XZ axis assembly  43  is pulled from elevator brackets  55  and printer  1 . To install XZ axis assembly  43  into elevator brackets  55 , vertical lateral plates  67  of XZ axis assembly plate  59  straddle vertical plates  69  of elevator bracket  55  and horizontal plate  71  of XZ axis assembly plate  59  is inserted into slots  73  at back end of elevator brackets  55 . Spring loaded pins  63  are retracted in the same manner as they were for removal. When spring loaded pins  63  lines up with holes  65  in elevator brackets  55 , pins  63  are released and secure XZ axis assembly  43  to elevator brackets  55 . 
         [0036]    Slots  73  are the same height as plate  71  thickness, providing a tight fit. Plate  71  in slots  73  in conjunction with pins  63  in holes, prevent XZ axis assembly  43  from moving vertically as well as fore and aft. 
         [0037]    Plates  67  of XZ axis assembly plate  59  extend over top of the vertical plates  69  of elevator brackets  55 . The tight tolerance of the width between plates  67  in relation to the distance between the elevator bracket plates  69  prevent horizontal side to side movement. 
         [0038]      FIGS. 9 a -9 c    show XZ axis assembly  43  with plates removed for clarity. Counterweight  75  is fixed to counterweight belt  77  which runs on idler pulleys  79  of X belt  81 . Counterweight  75  is mounted on linear bearing  83  which runs on bearing rod  85 . Bearing rod  85  is fixed at both ends to XZ axis assembly plate  59  (not shown). Counterweight  75  has the same (or lesser or greater) mass as filament motor assembly  89  which includes filament motor  5 , linear rail bearing  87  and print head assembly  3 . Counterweight  75  is on the side of the belt opposite filament motor assembly  89  so it moves in the opposite direction to that of the filament motor assembly  89  and serves to cancel (or minimize) horizontal inertia forces being transferred to the XZ axis assembly plate  59  during acceleration and deceleration of filament motor assembly  89  and minimize deflection and vibration of XZ axis assembly plate  59  and filament motor assembly  89  thus improving print quality. 
         [0039]    X drive belt  81  is on the same plane as X rail  91  thereby reducing unwanted torque which can cause assembly deflection or vibration that can reduce print quality. If the planes are in close proximity to each other the same is true. 
         [0040]    XZ axis assembly plate  59  has micro roller switches  93  that zero XZ axis assembly plate  59  relative to build platform  29  before each print. They extend beneath XZ axis assembly  43  in  6   c ,  6   f ,  8   a  and  8   b . Each switch  93 , when tripped, causes Z motor  45  on its respective side to stop. This ensures that both sides of XZ axis assembly  43  are at a prescribed distance from build platform  29  and that XZ axis assembly plate  59  is parallel to it and specifically due to the position of switches  93  relative to nozzle  17 , nozzle  17  is zeroed and the line of travel of nozzle  17  is parallel to build platform  29 . This alignment is necessary to ensure that nozzle  17  is close enough to build platform  29  to accurately lay the first layer of the part on build platform  29  but also ensuring that nozzle  17  does not collide with build platform  29 . 
         [0041]    Manual zeroing of the XZ axis assembly plate  59  is also possible.  FIGS. 10 a -10 c    show 3D printer  1  with the spool and spool tray removed. The top of lead screw  47  is accessible to the user. Slot recess  95  on the top of lead screw  47  receives a flat-blade screwdriver. If for any reason manual zeroing is required, a screwdriver can be used to rotate lead screw  47  to position nozzle  17  to the correct distance from build platform  29  and align front lower edge  97  of XZ axis assembly plate  59  parallel to build platform  29 . 
         [0042]    Variations may be made to some example embodiments, which may include combinations and sub-combinations of any of the above. The various embodiments presented above are merely examples and are in no way meant to limit the scope of this disclosure. Variations of the example embodiments described herein will be apparent to persons of ordinary skill in the art, such variations being within the intended scope of the present disclosure. In particular, features from one or more of the above-described embodiments may be selected to create alternative embodiments comprised of a sub-combination of features which may not be explicitly described above. In addition, features from one or more of the above-described embodiments may be selected and combined to create alternative embodiments comprised of a combination of features which may not be explicitly described above. Features suitable for such combinations and sub-combinations would be readily apparent to persons skilled in the art upon review of the present disclosure as a whole. The subject matter described herein intends to cover and embrace all suitable changes in technology.