As desktop 3D printers have inched towards something resembling the mainstream, manufacturers have upped their game across the board. Even the quality of filament that you can get today is far better than what was on the market in the olden days, back when a printer made out of laser-cut birch wasn’t an uncommon sight at the local makerspace. Now, even the cheap rolls are wound fairly well and are of a consistent diameter. For most folks, you just need to pick a well-reviewed brand, buy a roll, and get printing.
But as with everything else, there are exceptions. Some people are producing their own filaments, or want to make sure their extrusion rate is perfectly calibrated. For those that need the capability, the WInFiDEL from [Sasa Karanovic] can detect filament diameter in real-time while keeping the cost and complexity as low as possible. Even better, with both the hardware and software released as open source, it makes an excellent starting point for further development and customization.
[ArduinoNmore] took an interesting approach to designing a counter intended to accurately display how many meters of filament a 3D printer has used. The Filamentmeter looks a little bit like a 3D printed handheld tally counter (or lap counter) but instead of a button to advance each digit, the readout represents how many meters of filament have gone through the extruder.
Driving the digit rotation from the extruder motor itself means that even retractions are accounted for.
At first glance it may look like there is a motor hidden inside, or that the device is somehow sensing the filament directly. But it’s actually the movement of the extruder motor that drives the device. A small spur gear attached to the printer’s extruder drives a series of gears that advance the digits. This means that retractions — small reverses of the extruder motor during printing — are properly accounted for in the total, which is a nice touch.
[ArduinoNmore] designed this for the Ender 3, and the Filamentmeter relies on a specific extruder design and orientation to work properly. Of course, since it’s 3D printed, modifying the design for your own purposes should be pretty straightforward.
Curious? The design is being sold for a few bucks, and there is a free test piece one can print and use to confirm whether the design will work before mashing the buy button. Non-free printable 3D models can be a world of buyer beware, but test pieces and solid documentation are good ways to give buyers confidence in your work.
The insides of the unit are really quite intricate, with a clockwork-type elegance to them. You can see it all in the short video, embedded below.
When the Prusa i3 MK3 was released in 2017, it was marketed as being “bloody smart” thanks to the impressive number of sensors that had been packed into the printer. The update wasn’t really about improving print quality over the MK2, but rather to make the machine easier to use and more reliable. There was a system for resuming prints that had stopped during a power outage, a thermometer so the firmware could compensate against thermal drift in the inductive bed sensor, RPM detection on all of the cooling fans, and advanced Trinamic stepper drivers that could detect when the printer had slipped or gotten stuck.
The optical filament sensor of the Prusa i3 MK3.
But the most exciting upgrade of all was the new filament sensor. Using an optical encoder similar to what you’d find in a mouse, the Prusa i3 MK3 could detect when filament had been inserted into the extruder. This allowed the firmware to pause the print if the filament had run out, a feature that before this point was largely unheard of on consumer-grade desktop 3D printers. More than that, the optical encoder could also detect whether or not the filament was actually moving through the extruder.
In theory, this meant the MK3 could sense problems such as a jammed extruder or a tangle in the filament path that was keeping the spool from unrolling. Any other consumer 3D printer on the market would simply continue merrily along, not realizing that it wasn’t actually extruding any plastic. But the MK3 would be able to see that the filament had stalled and alert the user. The capabilities of the optical filament sensor represented a minor revolution in desktop 3D printing, and combined with the rest of the instrumentation in the MK3, promised to all but eradicate the heartbreak of failed prints.
Fast forward to February of 2019, and the announcement of the Prusa i3 MK3S. This relatively minor refresh of the printer collected up all the incremental tweaks that had been made during the production of the MK3, and didn’t really add any new features. Though it did delete one: the MK3S removed the optical encoder sensor used in the MK3, and with it the ability to sense filament movement. Users would have to decide if keeping the ability to detect clogs and tangles was worth giving up all of the other improvements offered by the update.
But why? What happened in those three years that made Prusa Research decide to abandon what promised to be a huge usability improvement for their flagship product? The answer is an interesting look at how even the cleverest of engineering solutions don’t always work as expected in the real-world.
If you have had a 3D printer for awhile, you know the heartbreak of coming in to check on an 8-hour print only to find that in hour 7 you ran out of filament (or the filament broke) and your printer has been dutifully moving around for no reason. [Chuck Hellebuyck] knows and he decided to make a filament sensor he found on Thingiverse.
Finding a part on Thingiverse and printing it probably doesn’t warrant much attention. But if you watch the video, below, it is a good example of how things from Thingiverse don’t always meet your needs. The microswitch [Chuck] had was bigger than the design used. So he loaded the STL file into TinkerCAD and fixed it. He shows you exactly how he did it. That’s a useful skill because you never know when you’ll need to modify some part you’ve found on the Internet.
It doesn’t happen that often, but this is the last time that [Lucas] comes back from hours of unattended 3D printing to find a large portion of plastic spaghetti mess and a partly disassembled Kossel. The crash sensor he designed will now safely halt the printer if it detects that something went wrong during the print.
