GBX Update June 16 2021

Hi everyone! Here are the GBX R&D updates from the past month:


Manufacturing Rail Rollers In House

For all the hopper gantry designs, the gantry movement is enabled by rollers that slide within rails mounted in the X and Y directions. The rollers are purchased from PBC Linear, and they consist of a block to which two standard and one eccentric bearing are attached. The rollers are fitted to the rail by adjusting the position of the eccentric bearing.

To save cost and to customize the geometry of the rollers, the standard and eccentric bearings were purchased separately, and the roller block was designed for machining in-house. The new design simplifies the rollers in the Y direction by replacing the current two small, purchased rollers into a single long roller with two standard and two eccentric bearings. The new roller spans the entire Y length of the endtruck, and the increased length gives more stability against movement in axes other than the Y direction.

The X roller was similarly updated, with its length extended to span the entire hopper trolley. The X roller has two standard and one eccentric bearing.


Modular GBX Nozzles

Gigabot X has four standard nozzle sizes-- 0.4mm, 0.8mm, 1.75mm, and 2.85mm-- and additional custom nozzle sizes can be machined. The 0.4mm and 0.8mm nozzles are standard E3D nozzles with an M6 threading, the same nozzles used in many commercial desktop 3D printers. To install them on GBX, there is a machined adapter that screws on to the end of the extruder barrel on one end, and is tapped with M6 threading on the other end to accept a standard E3D nozzle. By contrast, the 1.75mm and 2.85mm nozzles were previously machined out of the same nozzle blank as the adapter, and they screwed directly onto the extruder barrel. This meant that to obtain an adequate seal to prevent leaking during printing, a ⅝” wrench and a vise grip were necessary to put enough torque into the nozzle to tighten it onto the extruder barrel.

The nozzle may be changed out for the following reasons:

  • Switching nozzle sizes
  • Troubleshooting a clogged nozzle
  • Replacing a nozzle for general maintenance

To make it easier to change the nozzle, the larger 1.75mm and 2.85mm nozzles were redesigned to mimic the 0.4mm and 0.8mm nozzles, allowing all nozzle sizes to interface with the M6 tapped hole of the machined adapter. This reduces the number of tools necessary to change the nozzle, and reduces the time from 0.5 - 1 hours to a few minutes. The 1.75mm and 2.85mm nozzles are machined from 0.8mm hardened steel nozzles by drilling out a larger orifice and adding a flat. The dimensions of the flat are determined by the nozzle size, layer width, and layer height using the calculations from this source.


re:3D has started managing firmware versions for various printers on Github. The most recent stable firmware version is 4.2.3, which was extensively tested on in-house printers at re:3D’s Houston office before its release in Q4 2019. Since then, 4.2.3 has been uploaded on all outgoing customer printers.

At the beginning of 2021, GBX 4.2.4 firmware was developed and hosted on re:3D’s Github account. The 4.2.4 version is still in development and testing stages, but since it is hosted on Github, it can be viewed and downloaded by anyone willing to use the most recent, unstable firmware version. Github also makes it easier to track firmware changes between different versions, making it in-line with re:3D’s culture of being open-source.

The changes in the GBX 4.2.4 firmware over the 4.2.3 firmware include:

  • Infrastructure for eventual integration of a touchscreen to replace the Viki interface
  • Customized settings for Terabot X
  • Updated build volumes
  • Updated preheat temperature settings for PET, PLA, PC, and TPU
  • A purging routine to purge material from the Viki menu
  • Revised menu options to remove filament-specific settings
  • Changing heater block numbering from 1, 2, 3 to 0, 1, 2 in all Viki menus to match Simplify 3D’s tool numbering system, which indexes from 0.
  • Dual extrusion code to accommodate an additional motor for an active feeding system, to be used to improve feeding flake into the GBX extruder
  • Updated pin assignments
  • New jerk and acceleration settings to improve print quality


GBX 1.4 Simplify 3D Profile

Like the firmware versions, the Simplify 3D profiles created by re:3D are also moving onto Github for version management. The most recent stable version is GBX 1.3, and the current version in development is GBX 1.4, which is available on re:3D’s Github account.

Changes between 1.3 and 1.4 profiles include updated:

  • Temperatures
  • Part cooling settings
  • Start script
  • Ooze settings
  • Top layers
  • Infill
  • Build size


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