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dr4wbac_ (tem, nikl, jakob)

Alternative Names

  • Drawback
  • Pencil Punk
  • HacksyDraw

Requirements

  • size for painting a3 paper
  • capstan drive
  • h bot for movement
  • easily to assemble / disassemble
    • removable thread of the capstan drive

Roadmap

Syntax: 1, 2, 1.1
- task 1 and 2 are independent from each other
- task 1.1 can only be executed after task 1
  • 1 cad & assemble all parts
  • 1.1 print parts (until friday ev)
  • 2 power electronics
    • 2.1 user interface (svg to motor control code)
  • 3 toolpath planning: svg in -> toolpath out
  • 100 make video

availability friday

  • matthias 9 bis 14.30, ab 18.00
  • niklas 15.00 bis ...
  • jakob ab 10.00

next steps

  • friday 12.00: all single parts modeled
  • friday 15.00: all parts assembled (the other person does driver)

References

Other drawing bots

  • https://watercolorbot.com/
  • axidraw

Mechanical Design

  - main.FCStd (full assembly)
  - skeleton.FCStd (skeleton containing spreadsheet)
  - component
    - component.FCStd (assembly of component)
    - component_part.FCStd (part of the component)
    - component_part_2 (assembly that is a part of component)
      - component_part_2.FCStd
  • keep folder structure as flat as possible
  • Have everything as .FCStd. Convert if needed.
  • one FCStd file per part/assembly

BOM

take 3d models from urumbot

model in cad or find 3d models from somewher else, e.g. from here

probabably easy to get

    1. v-bearing (5x)
    1. capstan (2x) (take from urumbot) ✅
    1. idler (2x) (take from urumbot) ✅
  • 7.1) extrusion vertical (1x) ✅
  • 7.2) extrusion horizontal (1x) ✅
    1. stepper motor (2x) ✅
    1. wire (1x)
    1. servo motor ✅

probably model ourselfs

    1. mounting plate v bearing (1x)
    1. sledge ✅ + assemble it (2x)
    1. extrusion cap head (1x)
    1. flexture
    1. mounting plate servo (1x)
    1. mounting plate stepper motor (2x)
    1. pcbs

do not model

    1. motor enclosure right (1x) (DEPRECATED)
    1. motor enclosure left (1x) (DEPRECATED)
    1. sledge case (1x) (DEPRECATED)

todo (jakob)

  • capstan drive urumbot durchlesen

to ask ferdi

  • what do you think of our design?
    • you somehow have to attach the two carriers. do that in 4 points. maybe print clamps for that
    • for the upper carrier, design something on your own. reason is, you need to add somehow the v wheels
  • which material do we take for attaching motors and v bearings to the end of the extrusions?
    • alimunum sheets. thickness 4 to 5mm (we have 5mm, 41mm width). they are in the top right shelf next to the carvera
  • any ideas for aufnahme of the pencil?
  • wie geht man bei pcbs vor? erst pcbs entwerfen oder nimmt man irgendein mock?
    • einfach nen quader reinklatschen
  • wie macht man das kabel fest?
    • siehe fahrrad baudenzug

design changes

  • removing 9 to place v bearings on same level as vertical extrusion
  • to do that we have to put v bearings at the end of the extrusion caps
  • do not use motor end caps but use metal or 3d printed plastic caps. ask ferdi, maybe also acrylic

Motor Driver

  • https://www.digikey.com/en/products/detail/texas-instruments/DRV8428PWPR/13563046
  • not in the lab. ordered
  • actually, they are in the lab
  • alternative: hbot firmware together with ramps
  • we fonud those at the 3d printer in the hackspace: https://www.allegromicro.com/~/media/Files/Datasheets/A4988-Datasheet.ashx
  • can you use different stepper drivers in one project?

Toolpaths

  • gcode to motor action
  • urumbu uses https://github.com/SeanP2001/Urumbu_USB_Stepper_Motor
  • if urumbu is used, use sampo stuff: https://gitlab.com/fab-lab-oulu/sampo
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