T-REX 300 – A completely new printer based on a old one

T REX 300 3D printer - Front view render — Front view render

The T-REX 300 3D printer is based on the design of the Profabb Gate XL printer . The Gate LE is a very old design which was made a few years ago when the rep-rap printers were getting popular in my country. It required many modifications to improve numerous construction errors.

I decided to share this project, because some of the parts / modifications might be useful for someone that owns this printer. There are so many modifications that I’ve decided to give this project / construction a new name (there are only a few parts left from the previous printer).

The design of the entire printer was made in the Autodesk Inventor software. During the design process I needed to reverse engineer all dimensions of the original parts. Then I’ve designed new parts that were intended for transplantation. Everything was measured with use of calipers and other very complicated measuring devices.

Definitely the hardest thing to do was to properly design the X-end and X-axis carriage, so that no significant changes to the printer’s frame would be required. The whole process took about 2 weeks of free time. It’s safe to say that it would be much easier to build a new printer from scratch than to redesign the old one.

Overall, I’ve designed and built a new printer over here.

NOTE: There are missing parts in most of the renders (bearings,bolts,nuts etc.).

NOTE2: This article is not fully finished yet, (I need to rewrite some paragraphs, because I’m not happy with this article in its current form).

Below I will try to describe everything as good as I can:

List of modifications in comparison to the old printer:

Y-axis platform linear bearings mount block were redesigned, the previous ones were too weak. New two-part clamps printed with ABS filament effectively stiffen connection between steel platform and the bearing itself. Everything fits the old holes in the steel platform. In addition, the Y axis platform has been lowered by a few millimeters (Build area has got expanded in Z-axis direction):

T REX 300 3D printer - Y axis platform bearings brackets — Y axis platform bearings brackets

T REX 300 3D printer - Y axis render — Y axis render

Y-axis belt idler assembly has been reinforced with use of some CNC- milled aluminium angles. Previously, the whole thing was bolted down to the frame with use of only one screw. (this bolt was bending slightly when the belt was fully tensioned ):

T REX 300 3D printer - Y axis belt idler (2 flange bearings) — Y axis belt idler

I’ve also designed a new enclosure for the Ramps in the way it fits nicely to the printer frame. All wires can be hidden inside so that none of them is visible. There are also some vent holes and a place for 120 mm fan just to improve the cooling of some active parts (Mosfets etc.). Everything is assembled with use of some M3 screws.

T REX 300 3D printer - Ramps cable management — Ramps cable management

I’ve designed new Z-axis stepper motors mounting brackets. They are made of 3 mm thick aluminium plate that was laser cut. Previous mounting brackets that were 3D-printed were bending too much.

T REX 300 3D printer - Z axis stepper motor mount — Z axis stepper motor mount

T REX 300 3D printer - Z axis stepper motor mount 2 — Z axis stepper motor mount 2

T REX 300 3D printer - Z axis stepper motor mount render — Z axis stepper motor mount render

X-End’s were redesigned in the way that they are much more rigid when comparing to the old 3D-printed ones. These new X-ends are based on laser cut aluminium backplates to which everything is bolted down. X axis stepper motor mount bracket is integrated into the X-end backplate. Because of that it isn’t bending when the belt is fully tensioned.

T REX 300 3D printer - X axis front view — X axis front view

T REX 300 3d printer - X end z axis leadscrew mount — X end z axis leadscrew mount

I’ve designed a nice spool holder which can be easily adjusted to fit almost any filament spool that is available on the market. Friction between the spool and the holder can be adjusted so that filament doesn’t unwind by itself.

T REX 300 3D printer - Filament spool holder — Filament spool holder

T REX 300 3D printer - Filament spool holder 2 — Filament spool holder 2

Extruder assembly has been completely redesigned. I’ve added a 3:1 gearbox based on HTD3M timing belt just to increase the holding torque and step resolution available at the output. Everything was designed in the way that no build volume was lost (without interference with old parts). This extruder was designed to fit a genuine E3D v6 hotend. The filament is pressed against the hobbed bolt with use of two springs. Tension of these springs can be easily adjusted with 2 M3 screws that are located at the side of it.

T REX 300 3D printer - X axis carriage front view — X axis carriage front view

T REX 300 3D printer - Geared extruder HTD3M belt — Geared extruder HTD3M belt

T REX 300 3D printer - X axis carriage rear view — X axis carriage rear view

New modular X-axis carriage is based on four linear bearings. In the previous design there were only 3 linear bearings which were a bit loose (I felt this “looseness” when I was moving the whole carriage with my hand). It is made of 2 3D printed halves that connect together with use of 6 M3 bolts/screws.

T REX 300 3D printer - X axis carriage render — X axis carriage render

I’ve also designed a simpler version of the extruder that has no gearbox and the springs don’t press the filament against the hobbed gear (it stays in a fixed position):

T REX 300 3D printer - Direct extruder render — Direct extruder render

On the new X-axis carriage there are many holes that allow you to attach many accessories very easily (for ex. a laser,cooling fan,leveling sensor,servo etc.):