Category: Adventures in modern manufacturing: 3d printing

3D printing, additive manufacturing, fused deposition modeling…it’s a bit of a minefield at times. So a few random tips, collected as recalled or experienced…

In your slicer, find the first layer speed setting and cut it to 50%. The first layer is crucial so make sure it gets laid down properly. PrusaSlicer and Cura both offer this so take advantage of it.

I hope this link doesn’t go stale: it’s a much better way to dial in a first layer, especially for the Prusa with its live Z offset. Takes just a few minutes and is better than the supplied first layer calibration or any home-brew array of squares at different offsets.

Adhesion issues on metal beds can often be resolved with soap and water…a drop of dish soap, a good scrub with a scouring pad, rinse and dry. It’s not a bad thing for glass beds either. Get in the habit of doing that at the start and solve adhesion issues before they start.

Bed leveling is easier with receipt paper, that thin thermal stuff you get from most stores these days. Thinner than copy paper and easier to work with…(h/t my much more experienced 3D model making pal Ken)

Metal beds > glass beds, for me anyway. Easier part removal through faster cooling and the ability to flex the bed and pop the pieces off.

Slower/higher quality is better. The time for a print to complete happens once. The moments when you look at something rough and raggedy-looking last as long as the part does. Go for quality.

As a test print/project, find the tool holder for your model on whatever model site you like and make it. Having those tools handy is good and it’s a good test of the machine’s capabilities. More useful than a benchy…

A camera to monitor the process is good and if you are going that far, may as well go with Octoprint. See an earlier post on that.

On purchasing choices…

Having worked with machines from AnyCubic, Creality, and Prusa (loaned as it wasn’t working), I would buy AnyCubic again before the others. Dual Z-axis machines > single Z, for stability and alignment. More expensive, as you need another motor as well as the hardware, but one less thing to worry about. Only the Prusa MK3S  has bed levelling (a misnomer: it doesn’t level the bed so much as map it out and work from that map) but that doesn’t mean I have never had to mess with the setup. As much or more than the other two; in fact I would say more than the AnyCubic i3 Mega S, the least sophisticated of the three.

The Prusa and Creality Ender 3 are quieter: the Prusa is silent when it’s not actively working, as as the Mega S now that the internal fans have been replaced with Noctuas. Noisy while working but silent once they cool down. The fan on the Ender is all you hear and the internal fans cannot be turned off with gcode commands so replacing them may be on the agenda.

AnyCubic and Creality both offer machines that can sell for  as little as $100. You don’t get automatic feeding or runout detection at the low end but you can live without those. And they can be added: all these machines are hackable. Bed leveling/mesh mapping can be added as well.

The Prusa MK3S looks and sounds like a great machine and when it worked, it was great. Lots of control/visibility into the process, adjustable speeds and temps and Z-offset, plus active firmware development, all good things. But I have some to think of it like an old European sports car…great when it works but plagued by gremlins when it doesn’t. A naff thermistor meant the bed temps were low and uneven which made adhesion touch and go. The extruder has issues with blobs and uneven filament deposition which either would leave turds on the work pieces or worse, knock the pieces over by being unable to clear the layer at which it was working. Took awhile to work that one out but I haven’t found a solution or anything beyond that symptom.

The Ender was beset with manufacturing issues. The Z-axis had to be shimmed with cardboard (helpfully provided in the packing materials) before the extruder would move freely. The adjustment of the X-axis is a bit subjective which can be confusing. The bed needs regular leveling, sometimes between jobs on the same day. Not sure it that the X-axis sagging or if the bed is actually drifting. A dual Z-axis machine would be better but also not $100.

The AnyCubic is ugly, has a crummy touchscreen interface (a natural fit for Octoprint), unsupported/has old firmware, but with the replacement of the glass bed for a magnetic metal one and the replacement of the internal fans, it’s actually pretty solid. Noisy — the steppers and controllers sound almost musical — and the UI is annoying: you still have to use it to load/unload filament. But it does have automated loading and runout detection, as well as being a dual-Z machine. You can upgrade firmware but my one attempt at that rendered it inoperable for 2-3 weeks until I was able to revert whatever happened. I think I will leave it alone.

For all that, it’s pretty reliable. The bed doesn’t move/need adjusting, it came with a spare hotend and a better set of tools that other two machines, and it mostly just works.

A time lapse from Octoprint/octolapse:

To make the magic happen, you need a Raspberry π board with PSU, an SD card (8Gb is plenty), and a camera. All of that can be had for well under $100, closer to $60 if you are careful. The Raspberry π cameras are fine but other options exist from Arducam and Inland. I have had three Raspberry π cameras fail in a month so I am not inclined to advocate for them. An Arducam model I bought to test worked first time and has given me no trouble. They both fit in the same size case and as bonus the ArduCam has a status light to let you know it’s working.

If you go with Raspberry π, the Camera Module 2 is what you will most likely want, as it is well-tested and supported. If you find the camera does not work or that the Raspberry π board doesn’t see it as connected, reboot the board and see if that clears it up. The command line methods for detecting the camera are not available if OctoPrint is running, so lsmod and friends are not there for you. But by the same token any Linux or other FOSS experience you have will come in handy.

You’ll need a case for the Raspberry π and the camera…so many options. I chose this one which has versions for the 3 and 4 boards. For the camera mount, I recommend something that mounts to the X-axis and can be adjusted to frame different points of view. For monitoring active jobs you want something that will cover the full print bed but for time lapses you want to shoot straight across the X-axis. Aiming straight back on the Y-axis or at 45° also work, if you can find a mount that allows it.. You might want to choose an articulated model in that case since the time lapse process will push the bed into the shot on each layer change. So something like this if you don’t want to make your own. Look on thingiverse as well…the kind that clip onto the QR code on the Ender are a good choice.

Which Raspberry π should you get? I have tried the 3 and 4 and have no preference. A model 3 with 1Gb of RAM is perfectly fine and at $35 (currently) it’s pretty friendly. The 4 can be had at the same price, if you can get one. The one drawback for the 3 is the USB micro B PSU, where the 4 and newer models use USB C. It was an issue for me as the case I initially chose for the 3 didn’t allow the PSU to be plugged in easily. The 4 is about $20 more at this writing (with 4Gb RAM: not a lot of choices sometimes, they are often in short supply).

You will need a USB cable to connect your Raspberry π to your printer. Many of them use the A/B type like a conventional printer so you likely have one. The Ender also uses the Micro B 🙄 so you may need to get one of those. Monoprice is a great place for cheap cables and has all kinds. Here’s one for $1.49.

Getting the Raspberry π imaged and setup and octoprint installed is documented at the Raspberry π site and at Octoprint and will be more up to date, but the short summary is to download the imager from Raspberrypi.com and let it set up your SD card. You can set up your hostname for the Raspberry π, your login info, WiFi credentials, and all of that in the imaging process. Put it in the Raspberry π board, and fire it up, do all the setup that is documented at Octoprint. Once it’s installed and you have logged in, install the Octolapse plugin. Hit the wrench icon to set up OctoPrint for the printer it will be controlling.

In the OptoLapse plugin these settings should deliver a timelapse video with the extruder out of the frame, letting the workpiece appear to grow out of the build plate as in the video above. Lighting and framing might be bigger challenges than the technology.

You can get more sophisticated with snapshot commands embedded in the gcode but I have not explored that. You will need to step through some options for OctoLapse (in the OptoLapse tab) based on the slicer you use: the automatic setting doesn’t actually work. OctoLapse will cancel any job you submit if you don’t fill out all the information about layer height, retraction distance/speed, etc. Save yourself some time and hassle by doing that.

If you use different slicers (Cura vs PrusaSlicer, for example) it might be worth setting different printer profiles that take that into account. So you may need separate Ender/Cura and Ender/PrusaSlicer profiles as the printer destination. That way OctoLapse knows when to trigger the snapshot function regardless of how you created the gcode file.