'Meter' Large Scale Printer
Chronological Project Progression
Timeline overview:
I designed the printer via. CAD in January 2021, began cutting and drilling the aluminum rails sometime around March, and have been sporadically printing components when needed via. both FDM and SLA throughout the entirety of the project. I spent time this summer implementing the tensioners and more mechanical aspects. There was also a learning curve involved in setting up the software hardware interfaces, and learning to configure for RepRap using GCODE commands.
Above: The current state of the printer. The foreseeable remaining tasks before completion are brief: I need to print and install the two plane bed tensioner, and possibly remodel the Y-axis belt tensioner, but this is not explicitly necessary, it would just make operation more convenient.
Endstop Programming & Configuration
X-axis testing
Y-axis testing
Z-axis testing
Redesigning Bed Roller Tensioners
I will be printing these via. FDM
The knobs will be tightened by turning them clockwise this time
Having the ability to control up/ down is very important for bed leveling. I didn't have an adequate way to do this before this change.
Implementing Redesigned Print Head
Designed the cooling ducts and fan brackets and printed them in resin.
The brackets sit on an E3D Hemera, which should allow me to print at a high flowrate.
Redesigning Print Head
Planning to print in resin to allow exceedingly thin walls and lack of stringing throughout internal air ducting.
The heatsink fan has an integrated limit switch bumper.
Ducting allows cold air to solidify molten plastic at a greater rate, increasing performance in printing overhangs and difficult geometry in general.
Initial Motion Testing
Z-Axis
Y-Axis- it took me awhile to get here, as prior to this, I was not able to program GCODE, not to mention the difficulties I initially faced in connecting the control board to a router via. a virtual terminal.
Installing Bed Tensioner
One side fully assembled.
The easy tensioning mechanism.
Designing the Bed Tensioner
This apparatus is meant to keep the print bed secured on the Y-axis rails.
Twisting the knobs pushes the rollers out via tension in the spring, pressing them firmly onto the aluminum rails.
Y-axis print bed assembly- I've yet to mount the rollers.
Lining up the X-axis on the Z rails.
X-axis mounted- properly tensioning the rollers was done via. elliptical bolts on the innermost rollers.
Z-axis screw placeholders with the X-axis mounted up.
Design, Implementation of Y-axis Motor and Tensioner Mounts
Although it is arguably easier to design and assemble, a disadvantage of my cartesian design is the weight (in the form of the print bed and the print itself) that must be carried along the Y-axis. To facilitate this weight, as of now I'm using two 40-42 NEMA stepper motors in a belt drive configuration.
Installing the Y-axis Rails
Installation tool.
Installed.
Printing the brackets.
All done.
Designing and Printing Print Head and Drive
An important aspect of my large format printer will be print speeds- I intend to print primarily from LW-PLA, a doped version of PLA with heat-released foaming components that allow volume expansion as a function of the heat block temperature. In order to reliably print using an expanding filament, not to mention at a respectable rate, the backpressure on the nozzle must be fairly high. The direct drive's proximity to the extruder ensures this feed pressure is maintained- a Bowden tube, in comparison, seems to dampen this pressure.
This is my first crack at a direct drive system- there are plenty of commercially available designs out there, and I may switch to one of those depending on how successful I am with this version.
Building Frame
The difficult part of this was achieving the precision needed when drilling the holes, and tapping the threading for the screws that hold things together. Having never really worked with aluminum before, this was a learning curve, but it worked out.
The completed base frame section of the printer, currently on the floor of my shed. I will need to get creative to house this thing.
The extent of what I've put together so far- the rest relies on printed parts, and my printers are tied up making rocket components at the moment.
Design and Exigence
By and large, when 3D printing an assembly, more parts means more attachment points, more attachment points means more surfaces, more surfaces mean greater volume, and finally, greater volume means greater weight. Therefore, the less parts, the lighter the aircraft, and the more control I have over weight distribution. Due to this, I have designed and recently begun constructing a printer capable of producing parts in the range of 960x600x960mm. Printers of this size are often coreXY as opposed to cartesian due to the efficiency disadvantages of mobilizing large and heavy parts on the Y axis. I went for a cartesian design for cost and construction reasons. CoreXY printers require more advanced control boards and the frames generally require a great deal more slotted framing.