Rostock
Release status: working
| Description | Rostock is a delta robot 3D printer prototype.
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Rostock is a delta robot 3D printer prototype, built in 2012 by Johann in Seattle, USA.
Design Goals
- Build volume: 200x200x400 mm (8x8x16 inches)
- Footprint: 300x350 mm (12x14 inches)
- Print surface: 200x200 mm heated glass which never moves
- Mass of end effector with hotend: less than 50 grams
- Positioning speed: up to 800 mm/s in all 3 directions
- Positioning accuracy: at least 30 steps/mm in all 3 directions
- Simplicity: fewer than 200 parts
- Hardware cost: less than $500 USD
Bill of Materials
See #Links for full BOM spreadsheet with vendors.
- Stepper motors: 4x NEMA 17 (3 positioning, 1 extruder).
- Timing belt pulleys: 3x GT2 plastic pulleys with 40 teeth, smaller would probably work better.
- Timing belt: 3x 1524 mm GT2 belt (2 mm pitch). Closed loops or open end is okay.
- Smooth rod: 6x 762x8 mm precision smooth rod. Drill rod is probably okay too.
- The length of belts and rods can be changed in the firmware.
- Ball bearings: 4x 608ZZ, 3x F608ZZ, 1x MR105ZZ. If you can't find F608ZZ, use 608ZZ with printed plastic flange.
- If using smaller pulleys, replace 608 (8x22x7 mm) with 688 (8x16x6 mm) or similar.
- Linear bearings: 6x LM8UU.
- Plastic parts: printed from PLA on Prusa Mendel.
- Fasteners: stainless steel, mostly M3 (some M4 and M8).
- Hotend: MakerGear hotend for 1.75 mm filament, 0.5 mm nozzle.
- Filament drive: Airtripper's direct drive extruder.
- Top and bottom frame: hand-cut plywood (300x350 mm baltic birch).
- Endstops: 3x ZM micro switch (pin plunger, no lever). You need only 3 top endstops. The bottom endstops are not necessary and will be removed from the design soon.
- Electronics: RAMPS 1.4 or any other RepRap board.
- Firmware: Modified Marlin (see #Links). This is a pretty hacky proof of concept. Hopefully we will have better firmware soon.
- Software: Same as other RepRap printers, e.g. OpenSCAD, Slic3r (see [1] for recommended settings), Printrun.
Tips and Tricks
Print with pronsole.py instead of pronterface.py if your prints have warts. They may be caused by Pronterface redrawing the G-code view while printing, which creates significant delay between segments. My modified Marlin firmware generates many shorter lines for each G1 command, so the Marlin look-ahead buffer will run empty if you don't send the next G1 command ASAP.
Future
The following improvements are planned for future versions:
- Remove bottom endstops because the top endstops are already micro-adjustable.
- Enable high-speed lift (Z motion) during retraction for travel moves.
- Use smaller timing belt pulleys and idler bearings.
- Use open end timing belt instead of requiring closed loops.
- Create a Mini Rostock variation with 120x120x120 mm build volume.
- Use OpenBeam aluminum extrusion instead of plywood frame.
- Use OpenRail (or hybrid roller slide directly on OpenBeam) instead of LM8UU and smooth rods.
- Experiment with dual extruders.
