For questions, specifically, about the Kossel family of printers. Questions about Delta printers in general have their own tag.

This tag is for questions, specifically, about the Kossel family of printers. Questions about printers, in general, have their own tag.

The Kossel 3D printer is a parametric delta printer, based o the Rostock 3D printer. From RepRapWiki - Kossel:

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.

The original printer has spawned a number of derivatives, which differ mainly in their size, but which are fundamentally the same design. Again, from RepRapWiki - Kossel:


There are several printers in the Kossel family.

Legacy Kossel

  • Spectra line instead of timing belt.
  • 623 bearings running directly on vertical 15 x 15 mm aluminum extrusion like 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.

There are other (generally larger) designs, from other contributors, namely from Terence and David Crocker, amongst others.

The original aims of this specific delta style printer design, as opposed to the more traditional cartesian style designs which are out there are:

Design Goals

  • Zero backlash.
  • Type: Delta printer
  • 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: unheated 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 (autoleveling).

(Source: RepRapWiki - Kossel)