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The FabMX 3D printer was designed to handle the (quite heavy) FabMX Pellet Extruder while keeping the printer compact and affordable.
Therefore this printer moves the print bed in two axes (a xy table) so the heavy extruder only has to be moved up and down (z axis).
It uses OpenBuilds linear actuators with modifications.

Specs:

• Build volume:  165mm x 165mm x 150mm
• Based on Laser4DIY Low Profile XY Table
• Uses 2 OpenBuilds NEMA17 V-Slot Actuators with Lead Screw for x and y axes (with modifications)
• plus 1 Open Builds C-Beam Linear Actuator for z axis

License

This FabMX 3D Printer with XY table is licensed under the CERN-OHL-P v2.

Parts List

Off-the-shelf parts

Custom parts

The custom parts are stored in this GitHub repository; https://github.com/ProjectFabMX/FabMX-3D-Printer

The "end plates" are made of 3 layers of lasercut aluminium, which are aligned and held together by M3 screws. It is also possible to have them CNC milled as one piece, but we chose laser cutting as it is much cheaper to get them produced this way.

Part Locations: 

Assembly

General notes:

• Please see included STEP file where the individual parts go.
• There are different types of slot t-nuts: slide-in and drop-in types. The slide-in type can only be inserted from the ends of the profile. If you have these types, make sure you insert the t-nuts at the right places before screwing on the endplates, otherwise they cannot be inserted any more
• Make sure the motor orientation is correct, i.e. the cable connector is on the correct side. See STEP file.
• The lasercut holes in the aluminium plates are often too small. Drill them out to have the right sizes so that the screws go through. The only exception are 4 holes in the bed plate (see below). These holes need an M3 thread to be cut into.

X and Y axes

• Start with assembling the "end plates". They are made of 3 layers of lasercut aluminium, which are aligned and held together by M3 screws and M3 on the inside. These screws and nuts are not included in the STEP.
• The wheels (we need 8 for build) consist of 4 parts: The wheel itself, 2 ball bearings and a shim. The shim goes between the 2 ball bearings. The wheel package can contain an addition shim and a lock nut, which are NOT needed for the wheels. Also see wheel build video here: https://openbuildspartstore.com/xtreme-solid-v-wheel-kit/
• The wheels are attached with 6mm spacers, with standard spacers on one side and eccentric spacers on the other side of the sled. The eccentric spacers can be used to increase the force the wheels press onto the beams.
• Cut an M3 thread into these holes in the bed plate:
  
  
  
• The heat bed holder plate (4 "arms", round shape) has to be connected with the bed plate using distance sleeves and M3x25 flat head screws. For these screws to sit flush, the holes in the head bed holder plate have to be count sunk.
  
  

Heat bed

• The heat bed is mounted on the heat bed holder plate using springs and tensioning nuts
  

Z axis

• Assemble the z-axis by connecting it to the extruder using the laser cut parts (see step file, self explanatory) 

Base

• After assembly, the X-Y-table is mounted on a separate linear rail, eventually connects the table and the z-axis
  • Therefore, four holes have to be drilled into the 20x80mm rail in order to be able to connect it to the table. (See step-file and drawing for measurements)
  • The exact position of the X-Y-table can still be adjusted later on
  • The connection of the z-axis to the rail is fairly easy and can be seen in the step file. Use the laser cut trapezoidal parts. 

Position of holes according to explanation above

• Once all components are mounted, the heat bed is moved to the maximum position towards the z-axis. Then, when assured the relative position between extruder (z-axis) and bed suits the functionality of the printer, the table can be fastened onto the connection rail.

Screenshot of CAD-Model as reference.

Copyright FabLab München e.V. 2023-2024

This source describes Open Hardware and is licensed under the CERN-OHL-P v2

You may redistribute and modify this documentation and make products using it under the terms of the CERN-OHL-P v2 (https:/cern.ch/cern-ohl).
This documentation is distributed WITHOUT ANY EXPRESS OR IMPLIED WARRANTY, INCLUDING OF MERCHANTABILITY, SATISFACTORY QUALITY AND FITNESS FOR A  PARTICULAR PURPOSE.
Please see the CERN-OHL-P v2 for applicable conditions