Kossel
Kossel
Release status: experimental
Kossel is a parametric delta robot 3D printer, built in 2012 by Johann in Seattle, USA, based on his Rostock prototype.
It is named after Albrecht Kossel, German biochemist and pioneer in the study of genetics. He was awarded the Nobel Prize for Physiology or Medicine in 1910 for his work in determining the chemical composition of nucleic acids, the genetic substance of biological cells.
Contents
History
There are several similar printers in the Kossel family.
Legacy Kossel
- Spectra Fishline instead of timing belt.
- 623 bearings running directly on vertical OpenBeam, 6 bearings per carriage.
- PG35L extruder directly on the end effector (moving platform).
- This design is deprecated but the source files are still available.
OpenBeam Kossel Pro
- Terence Tam's design for mass manufacturing.
- Successfully funded on Kickstarter.
- Stamped and injection molded parts instead of 3D printed.
Mini Kossel
- This is Johann's latest and stable version.
- The rest of this page describes the details of Mini Kossel.
Design Goals
- Zero backlash.
- Speed: 320 mm/s in all 3 directions.
- Resolution: 100 steps/mm in all 3 directions.
- Repeatability: better than 0.03 mm (30 micron)
- Build volume: cylindrical, 170mm diameter, 240mm height.
- Footprint: triangle, 300 mm width (240mm OpenBeam + printed corners).
- Frame height: 600 mm.
- Print surface: round glass, doesn't move.
- Mass of end effector with hotend: less than 50 grams.
- Simplicity: fewer than 200 parts.
- Hardware cost: less than $600 USD.
- Fully automatic print surface level calibration (autolevel).
Optionally scale down to fit within IATA hand luggage size limit:
- Frame height: 550 mm.
- Footprint: triangle, 270 mm width, 250 mm across (210mm OpenBeam + printed corners).
Bill of Materials
Printed parts
- 1x End effector
- 1x Retractable Z probe
- 2x Power supply bracket (optional)
- 3x Plate which includes the following parts:
- 3x Bottom vertex
- 3x Top vertex
- 3x Vertical carriage
- 6x Endstop holder
- 3x Print surface holder
At Johann's suggested settings of .2 layer height, 3 perims, 3 solid layers, 50% infill - the est. wt. of plastic is 0.4 kilos.
Frame
- 3x 600mm vertical OpenBeam or Misumi HFS3-1515
- 9x 240mm horizontal OpenBeam or Misumi HFS3-1515
- 1x Borosilicate glass print surface with 170mm diameter
Fasteners
- 100x M3x8mm stainless steel screws (frame and most connections)
- 100x M3 stainless steel nuts
- 100x M3 nyloc nuts
- 12x M3x25mm stainless steel screws (belt idlers and effector-rod attachments)
- 6x M3x35mm stainless steel screws (tensioners)
- 12x M3x16mm stainless steel screws (push rod attachment)
- 6x M2.5x12mm screws (micro switches)
- 3x M2.5x16mm (automatic bed leveling probe)
Linear motion
- 3x 400mm hardened steel rail and carriages HIWIN MGN-12H
- 3x 1164mm GT2 belt closed loop with 2mm pitch and 6mm width
- 6x F623ZZ flanged bearings 3x10x4mm (or F684ZZ 4x9x4mm for printed parts before June 21st)
- 3x GT2 pulley with 16 teeth and 2mm pitch
- 3x Kysan NEMA17 stepper motor
Diagonal push rods
- 12x Traxxas 5347 rod ends
- 12x M4x20mm set screws
- 6x 180mm Carbon tube ID=4mm
Bowden
- 1x Clear PFA tubing ID=2mm OD=4mm
- 2x Push fit connector ID=4mm with M5 thread (or bigger thread before June 21st)
Endstops
Automatic bed leveling probe
- 1x Micro switch (same as for endstops above)
- 1x Bondhus 1.5mm allen wrench
- 1x Safety pin with 2.5mm loop
- 2x Ball point pen spring
- 1x Euro-style terminal block connector
- 1x Heat shrink tubing ID=2mm
Electronics
Links
- Project blog on Tumblr
- Pictures on Flickr
- Mailing list for questions and answers
- OpenSCAD source files on GitHub for printed plastic parts.
- Modified Marlin firmware on GitHub for delta geometry on Arduino.
- Frame size calculator spreadsheet.