My 3D Printing Lab
- JD Wallace
- Dec 28, 2020
- 4 min read
Updated: Jan 1, 2021
In around 2014 I discovered 3D printing and had a ton of fun with the hobby. I recently came back to it after a few years of inactivity. A lot has changed and I'm still working to catch up, but wanted to document what I have learned so far. I'm sure there are plenty of new tools I've not even discovered yet; and I'll continue to experiment as I learn more, but for now I'm pretty satisfied with this setup.
Printer
Printrbot Simple Metal (1403) w/ Heated XL Bed Upgrade
A 2014 design, built like a tank. Discontinued and no longer supported, but still a wonderful machine. With new high quality printers still going for $1,000 or more; it's great to be able to continue to enjoy the hobby with this 6 year old printer. The Printrbot is a typical fused filament fabrication (FFF) style printer.
An 8 bit microcontroller board that shipped with the bed upgrade. This controller receives input from the thermistors, end-stops, and bed probe; provides power to the extruder and bed heaters; and drives the stepper motors that position the nozzle and extrudes the filament.
Firmware
The Printrbot's Printrboard originally shipped with a customized fork of Marlin 1.0 firmware. I've discovered the latest build of Marlin 2.0 not only works great, it's a serious enhancement in capability over the original; breathing new life into this older printer. It does require a bit of work to get this firmware installed, but I've written a tutorial here. The Marlin firmware is responsible for accepting g-code print commands and translating them into the right combination of coordinated hardware commands that will result in a clean print.
Controller
OctoPrint running on Raspberry Pi 4 8GB
The Printrboard built into the Printrbot is fully capable of driving all of the necessary hardware, and can even manage its own print jobs from g-code files loaded into the on-board microSD card reader. It's far more convenient however to have a more powerful computer managing higher level functions like job management and remote access. I could dedicate a traditional PC to this task; but OctoPrint running on a small Raspberry Pi offers a lot of features in a tiny package. The Raspberry Pi 4 8GB model might even be overkill for the job; but at only $75 it's an easy investment and ensures I'll have plenty of power to install any of the more than 250 plug-ins available for OctoPrint.
If you're looking for a more economical option, the RPi 4 2GB model is only $35 and OctoPrint will also run on any RPi 3B or newer you happen to have lying around.
Slicer
Most 3D models used in 3D printing are saved as STL files. These files describe the shape of the object, but lack any of the necessary detail to tell a printer how to print them. Software called a "slicer" is used to translate these STL files into g-code commands the fused filament fabrication printer can understand. In effect, it "slices" the model into layers and plots a linear path for the printer nozzle to follow in order to build each layer out of the extruded material. 3D models could be shared in raw g-code format, but since each 3D-printer could have a unique combination of capabilities, filament parameters, and print preferences; it makes far more sense to custom slice each model.
PrusaSlicer is a fork of the Slic3r project which is developed and optimized for the Prusa3D brand of printers. PrusaSlicer seems to have developed at a faster pace than the original Slic3r code it was forked from; likely due to the financial support afforded to it by Prusa Research. Despite being optimized for their own printers, I find it still works very well for my Printrbot.
Other Upgrades
The heated bed upgrade for my Printrbot originally shipped with a piece of Kapton tape to be applied to the print surface (it's the orange material in the first photo above). The Kapton was a big improvement over the blue painter's tape I had previously been using to help with print adhesion, however over time it had become scratched and damaged in a few places and needed to be replaced.
While researching a replacement for my damaged Kapton tape, I came across several references to a material called PEI that had gained in popularity as a print surface. I was able to find a sheet large enough to cover my entire print bed with adhesive pre-attached for only $14. I've only tried a few prints with it so far, but the results look pretty good.
A note on installation. I found several cheaper offerings for PEI sheets, but upon closer investigation realized they did not include adhesive. I could have purchased and installed adhesive on my own; but for $14 it was worth it to me to not have to worry about getting the lamination right. I also found it incredibly easy to cut the sheet to the proper size. I used a rotary paper trimmer first and then once the sheet was installed I used an x-acto knife to clean up the edge. The slightly more rigid nature of the PEI as compared to Kapton make it very easy to install without trapping any air bubbles.
My Printrbot was an earlier model that shipped with the Ubis 13 (a.k.a. Ubis Ceramic) hot end. The Ubis 13S is a compatible but improved version that is still be available, but you'll need to add a cooling fan which I've documented in this post.
Z-Axis Conversion
The Printrbot Simple Metal includes one proprietary consumable part that will eventually fail. The delrin z-nut that is threaded onto the 5mm z-axis screw will start to wear out over time and cause wobble or even worse, failure of travel in the z-axis. There is no longer a source for the original replacement part, but I do have a couple of options.
I can of course just print a replacement, and in fact I have done just that and stashed it in my spare parts bin just as a backup; however I'm not confident the tolerances would be precise enough to actually work.
The better solution, and the one I'm currently working to implement is to completely replace the z-axis screw with one that has a machined nut that will stand up to wear longer and presumably result in more stability for z-axis movements. This process has been documented by others here, and here. I'll document my own upgrade in another post once the parts have arrived.
Comments