The Hangprinter v4 is a an open-source RepRap 3D printer with a minimalist design. It utilizes a tethered printing head suspended on cables, allowing for mid-air printing without the constraints of a traditional build volume.

Our FAST lab has an upgraded Hangprinter v4 once nicknamed "Smooth Operator", though, no one really calls it that or even knows of the nick name.

Project Links

Main Project Page:'s_Hangprinter_v4



For questions regarding the project, please contact Janik.

Short preview of the Hangprinter v4 printing a shelf


After construction and assembly started with Ravneet in the summer of 2022, Janik has taken the torch and became the sole maintainer and operator of the machine.

Our hangprinter is built with the same parts and procedure outlined by Tobben in the Hangprinter v4 documentation. Any changes or alterations from the generic build are outlined below in Upgrades and Modifications section.

Technical Notes

The hangprinter kinematics act on a Cartesian axis system (x,y,z).

To address individual motors (with the kinematics bypass h2 command for example talked about lower down), the A line/anchor is the x axis, B is y, C is z, and the up/down lines aka the D-line is the u-axis. The extruder is always the e-axis.

In the past, our hangprinter has utilized a hemera extruder with a supervolcano hotend but now uses the E3D Revo™ High Flow Hotside.

Notable Commands

Use the GCode dictionary as a bible.

G92 x# y# z#

This "Set User Position" command lets you (once the hangprinter is positioned at the origin) home it as the origin with g92 x0 y0 z0. This basically tells the machine, "HEY! You current position is x# y# z# [whatever #'s you entered]".

G90 vs G91

G90 is "Set to Absolute Positioning", meaning, all following commands will be referencing absolute positions. So if G1 x10 y10 is entered next, the machine will go TO x10 y10.

G91 on the other hand is "Set to Relative Positioning". Meaning the same G1 x10 y10 entered after would go an ADDITIONAL 10 in the x and an ADDITIONAL 10 in the y relative to where the tool head is now.

G1 x# y# z#

G1, mentioned above, is the "Controlled linear move" command. Aka the move command. So something like g1 x10 (after g91) would move the tool head another +10 in the x axis. This command also applies to the u-axis and the e-axis (extruder).

Photo Gallery

Video Gallery

VIDEOS HERE: FAST's Hangprinter v4 videos

Upgrades and Modifications

Upgraded PSU

PSU upgraded to SE-1000-24 (24VDC at 41.7A - 1000W).

Upgraded Triangle

The triangle chassis is upgraded to use 2040 aluminum extrusion rather than the wooden beams. All CAD available in the Onshape link.

Triangle Duet Toolboard

To keep a clean (and easily swappable) wire harness between the main duet and the triangle chassis, we opted to use a Duet 3 Toolboard 1LC on the triangle. This allows for all extruder steppers, heaters, and fans to be controlled via a CAN bus and all power run through two extra wires.

This is designed to make it easy to swap tools (each tool having its own 1LC that will be connected and disconnected) on the triangle. In our case, between a filament and pellet extruder.

Blog and Updates

First Print on the Rebuilt Smooth Operator, June 5th 2024

Some ways through upgrades (still ways to go) and construction, with an initial manual calibration and absolutely no tuning or slicer adjustments, Rav and Janik rushed to start a print just to see the machine work some magic. The result: a very rough benchy. No where close to the result the team is working towards, but rather evidence they are along the right path.

Little history run down as of May 10th, 2024

Following its initial construction in the summer and fall of 2022, the hangprinter has undergone gradual tuning. However, during the fall/winter of 2023, the lab room which housed the hangprinter was unavailable for constructions and hence the printer had been taken down. Now with the lab open again, the trio of Janik, Rav, and Troy are preparing some repairs and upgrades before once again rehanging the machine.

FA info icon.svg Angle down icon.svg Page data
Keywords hangprinter, fast, western, free appropriate sustainability technology
Authors Jahangir (Janik) Abdullayev
License CC-BY-SA-4.0
Organizations FAST
Language English (en)
Related 0 subpages, 3 pages link here
Impact page views
Created March 24, 2024 by Jahangir (Janik) Abdullayev
Modified June 6, 2024 by Jahangir (Janik) Abdullayev
Cookies help us deliver our services. By using our services, you agree to our use of cookies.