3D Printer Ashtar D (Draft)

Status: just a draft

Ashtar D (Classic XY)

Updates:

  • 2021/01/14: very experimental IDEX upgrade option added
  • 2021/01/08: starting with details of Y belt/pulley (non-)printable parts
  • 2020/12/28: beautifying X & Y motor and pulley mounts with rcube(), rcylinder() and chainhull()
  • 2020/12/25: starting with some basic parametric enclosure, refining some details
  • 2020/12/24: X & Y motor mounts as well X & Y pulley mounts done
  • 2020/12/23: starting with Ashtar C frame and transforming it to classic X/Y head, X/Y motor mounts and pulleys mounts missing

Introduction

After the Core XY of Ashtar C I thought to convert it to a more classic kinematic X/Y head with two dedicated NEMA17 motors for each axis – independent XY. Mostly using the same frame setup with 500mm alu extrusions, same V-carriages/modules as before, but reposition both motors to dedicate for X and Y axis now. The main goal is to achieve 400x400mm print area with 500mm alu extrusions.

Ashtar D (Classic XY)

  • X motor & Y motor
  • no XY frame tension
  • shorter belts
  • one moving motor (Y-wise)

Ashtar C (Core XY)

  • Core XY with motor A & B
  • XY frame tension
  • long belts
  • no moving motors

Draft

  • Bare without mounts
  • X = max, Y = 0
  • X = max, Y = max
  • With X & Y motor mounts and X & Y pulley mounts
  • Including 3 Bowden extruders and LCD controller
  • 3 Bowden extruders and LCD controller
  • Parametric enclosure for Ashtar D, moving LCD controller in front bottom

After the rough design was OK, with X = 0 .. max and Y = 0 .. max and maintaining max of printable area, I went ahead and did basic Y motor mount and X motor mount, and I was designing the pieces in OpenSCAD, the ad_[xy]mount(type="motor" or "pulley") and I changed the 42×42 interface for NEMA17 to pulley holder which made it quite a fast design – so motor-side and pulley-side are very similar made with the same OpenSCAD module:

Y Motor Mount

  • ad_ymount(type=”pulley”) in the front, and ad_ymount(type=”motor”) in the back

At Y = max + Y margin (beyond print bed, but not yet touching anything else):

  • At Y = max+ Y margin
  • Back view
  • Top view

X Motor Mount

Exploring the X & Y minimum, how X carriage can as close as possible with the part cooler attached:

  • At X = -12, Y = 0
  • At X = -12, Y = 0
  • At X = -12, Y = -10

X & Y Motors / Axis

  • Ashtar D: Y carriage with X motor mount and X pulley (on the other side)
    Y motor mount and shaft extender and Y pulley
  • Ashtar D: Y pulley mount and X pulley mount on Y carriage (in the front)

Specifications

  • Build Volume: ~380 x 400 x 380mm (not yet finalized)
  • Frame: 17x 500mm 2020 alu profiles
    • 14x 500mm 2020 T-slot alu profiles
    • 3x 500mm 2020 V-slot alu profiles
  • T-Slot 2020
  • V-Slot 2020
  • V wheel

Issues to Resolve

  • mounting X motor, resolved
    • mounting X pulleys, done
  • mounting Y motor, resolved
    • mounting Y pulleys, done
    • using M6 or M5 smooth or threaded rod to extend Y motor shaft
  • Y belt mount to carriage, done
  • positioning: extruders, controller, power-supply (like Ashtar C)
  • positioning: X, Y and Z end-switches
  • tuning toward 400x400x400mm build volume with 500mm 2020 alu profiles
  • build printer
  • print tests
  • release parts
  • release code

Gallery

Classic XY vs Core XY

Compared to Ashtar C Core XY the Ashtar D is less elegant, more complex parts but better setup using the rather thin 2020 alu profiles for such a big build volume.

  • Ashtar C: Core XY
  • Ashtar D: Classic XY
  • Ashtar C: Core XY
  • Ashtar D: Classic XY

Sharp vs Rounded Edges

  • Sharp edges of X & Y motor & pulley mounts
  • Round edges of X & Y motor & pulley mounts

The round edges are achieved by replacing cube([x,y,z]) with rcube([x,y,z],r) and in conjunction with chainhull() { } the round edges propagate. Actual prints will show if any drawbacks appear, e.g. it introduces some small overhangs, but they might be disregarded at small radiuses/radii.

Toward Elegance

  • Just cube()
  • Using rcube()
  • Using cylinder() & cube()
  • Using rcylinder() & rcube()
  • Final version, using rcylinder() and rcube()

IDEX Option

In order to provide Dual Independent Extrusion (IDEX) a 2nd belt and motor is required, yet, the Y carriage is quite delicate in this current setup but after some pondering I think I came up with an elegant solution: the main idea is to utilize the NEMA 17 shaft as axis for 2nd belt idler:

  • Reusing NEMA 17 shaft as axis for idler
  • Reusing NEMA 17 shaft as axis for idler (see through)

and then rotate the same Y carriage on the other side:

Since the entire Ashtar D design is still just a draft, this IDEX setup is also very experimental in nature and only actual build will tell if it’s feasible.

  • Ashtar D
  • Ashtar D IDEX
  • Ashtar D
  • Ashtar D IDEX

Gallery

Z Axis & Motors

It has been tested successfully with Ashtar C, so I use the same setup again:

Ashtar C/D: Z Axis / Motor
  • Ashtar C/D: Z motor mount
  • Ashtar C/D: Z motor and Z axis

Parts

Printable Parts

  • 1x ad_xmount-type=motor
  • 1x ad_xmount-type=pulley
  • 1x ad_ymount-type=motor
  • 1x ad_ymount-type=pulley
  • 1x ad_ypulley-left
  • 1x ad_ypulley-right

Note: the new parts aren’t released yet until I used them in a test setup.

Non-Printable Parts

  • 2x 625ZZ bearings ID=5mm
    • 2x for 1x ad_ymount-type=pulley
  • 12x 629ZZ bearings ID=6mm
    • 8x for 4x Z thread holder (2x bottom)
    • 4x for 4x Z thread holder (top)
  • nx pulleys (dimension not yet determined)
    • 2x (5mm hole) for 2x Z motors
    • 1x (5mm hole) for 1x X motor
    • 2x (5mm hole) for 1x Y motor, 1x ad_ymount-type=pulley
    • 4x (6mm hole) for Z threaded rods
  • nx idlers (with 3 or 5mm hole)
    • 2x (3mm hole) for 1x ad_ypulley-left, 1x ad_ypulley-right
  • ~520 mm M5 smooth or threaded rod (Y shaft extension)

Enclosure

Developing some enclosure, either attach to the Z beams – as one side is free to fasten pieces and use acrylic sheets – or enclose entire frame, like with

or doing my own approach, something like this:

  • Acrylic enclosure (draft)
  • White enclosure (draft)
  • Acrylic enclosure, 3 extruders, LCD controller

With the enclosure the display must be reachable, and therefore likely be on the front and longer wires from the controller board, which most likely resides on the back right side as with Ashtar C.

  • Ultimaker S5
  • Makerbot Replicator
  • Creality CR5
  • Creality Ender 6

Ashtar D (Classic XY)

  • Build Volume: 380 x 400 x 380mm (57.7Kcm3 / 57.7L) = 100%
  • Device Dimension: 590 x 650 x 620mm (237Kcm3 / 237L)
  • Build vs Device Volume: 4.11

Creality CR5

  • Build Volume: 300 x 225 x 380mm (25.6Kcm3 / 25.6L) = 44%
  • Device Dimension: 530 x 487 x 621mm (160Kcm3 / 160L)
  • Build vs Device Volume: 6.25

Ultimaker S5

  • Build Volume: 320 x 240 x 300mm (23.0Kcm3 / 23L) = 40%
  • Device Dimension: 495 x 585 x 780mm (225Kcm3 / 225L)
  • Build vs Device Volume: 9.78

Creality Ender 6

  • Build Volume: 250 x 250 x 400mm (25.0kcm3 / 25L) = 43%
  • Device Dimension: 495 x 495 x 650mm (159Kcm3 / 159L)
  • Build vs Device Volume: 6.36

Ashtar D and Ultimaker S5 device volumes are nearly the same, 237Kcm3 vs 225Kcm3, but Ashtar D would print more than the double of the volume – so it would be volume-wise more efficient. Creality CR5 and Creality Ender 6 are more volume efficient than the Ultimaker S5, but not as good Ashtar D. Let’s see if I can keep this advantage for the final implementation.

References

  • Ultimaker S5: different XY head design using smooth rods, head: XY, bed: Z, build volume: 330 x 240 x 300mm, swapable hotends/printcores; priced at EUR/USD 6,500+ (2020/12)
  • Makerbot Replicator: head: XY, bed: Z, build volume: 295 x 195 x 165mm, priced EUR/USD 2,400 (2020/12)
  • Creality CR5: blatant copy of Ultimaker 2, S3 & S5 case design, head: XY, bed: Z, build volume: 300 x 225 x 380mm, priced EUR/USD 1,500 (2020/12)
  • Creality Ender 6: low cost Core XY, head: XY, bed: Z, build volume: 250 x 250 x 400mm, priced EUR/USD 500 (2020/12)

See Also (Ashtar Series & Parts)