Toolchanging Printers Get A Nozzle Hanky Like No Other

When it comes to toolchanging 3D printers, idle nozzles tend to drool. Cleaning out that nozzle goo, though, is critical before switching them into use. And since switching nozzles can happen hundreds of timesĀ per print, having a rock-solid cleaning solution is key to making crisp clean parts. [Kevin Mardirossian] wasn’t too thrilled with the existing solutions for cleaning, so he developed the Pebble Wiper, a production worthy nozzle wicking widget that’s wicked away nozzles thousands of times flawlessly.

With a little inspiration from [BigBrain3D’s] retractable purge mechanism, [Kevin] is first purging tools onto a brass brad. Rather than have filament extrude into free space, it collects into a small bloblike “pebble” that cools quickly into a controlled shape. From here, after one quick flick with a servo arm and a small wipe with a silicone basting brush, the nozzle is ready to use. The setup might sound simple, but it’s the result of thousands and thousands of tests with the goal of letting no residual ooze attach itself to the actual part being printed. And that’s after [Kevin] put the time into scratch-building his own toolchanging 3D printer to test it on first. Finally, he’s kindly made the files available online on Github for other hackers’ tinkering and mischief.

So how well does it work? Judging by the results he’s shared, we think spectacularly. Since adopting it, he’s dropped any sacrificial printing artefacts on the bed entirely and been able to consistently pull off stunning multimaterial prints flawlessly with no signs of residual nozzle drool. While toolchanging systems have been great platforms for hacking and exploration, [Kevin’s] Pebble Wiper takes these machines one step closer at hitting “production-level” of reliability that minimizes waste. And who knows? Maybe all those pebbles can be sized to be ground up, remade into filament, and respooled back into usable filament?

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Fail Of The Week: The 3D Printer Nozzle Wipe That Won’t

Some of you will be familiar with the idea of using a brush as a nozzle wipe on a 3D printer. The idea is that passing the hot end over the brush cleans any stray plastic from the nozzle, ensuring that those plastic bits don’t end up in unwelcome places. [Mark Rehorst] attempted to implement a nozzle brush system in his own printer, but hasn’t so far been successful.

One of the things [Mark] makes is 3D printed lamp shades and this led to his experiments in setting up an automatic nozzle cleaner. Despite best efforts, the hot ends of 3D printers can occasionally accumulate bits of molten plastic which can sometimes end up deposited on the print. Because the lamp shades are so thin and so big, having a charred blob end up on the print is pretty unwelcome. Having the nozzle automatically wiped clean would be a very handy feature, but is proving to be a troublesome one.

[Mark] based his design on a small, dense wire brush used for cleaning the print nozzle of a Stratasys printer. Sadly, he found no combination of motion or brush height that got the nozzle reliably clean every time. Sometimes a blob would be dislodged, but the hot end would pick it back up again on subsequent passes. You can see it in slow motion from a variety of angles in the video below.

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