Stripped again, and out of tubes

I was trying out some semi-transparent blue filament from UniCoFil. The temperature tower had quite a bit of stringing, so I tried with 2mm retraction. That, unfortunately, led to stripping when the next temperature tower got to 195C. Despite trying to help the filament come out, unloading didn't work, so I had to snip the filament and open up the extruder.

TIP: When snipping the filament, do so with as much filament above the PTFE tube as possible, to more easily grab it later.

I disassembled enough to have the heater assembly free and tried a cold pull, but there wasn't enough filament sticking out to get a good grip. So I unscrewed the heatsink (this time the heatbreak didn't follow) and could get the PTFE tube out easily. Not so the filament. I tried heating the tube on the bed and then pulling, but again with not enough to pull on. Eventually I used a small hex wrench to push out out from the other end, which worked.

Then I put the PTFE tube back in the heatsink, which was a mistake. I put it so far in that I couldn't screw the heatsink onto the heatbreak, and I wasn't able to pull it out without destroying it. Fortunately, I had a second one. Need to get more replacements, and maybe just a spare of each part.

Having mounted the heatsink on the heatbreak, I could insert the PTFE tube, but not quite enough, now the end would block the gears. So I took it apart again, pushed the PTFE a bit further in, and then it looked OK from my point of view. Not so from an actual functional point of view, it was high enough to hit the gears still. It needs to be barely visible above the edge of the hole.

I tried to align it better, but it took more squeezing than it really ought to, and one I had it in, the nozzle ended up being too low, possible because I couldn't screw the heatbreak far enough in. I will order a bunch of new tubes and spare other things, take the whole shebang apart, and then try first to install from fresh with a new tube, if that doesn't work then replace the heatsink - I think the black insert inside it has gotten damaged.

Nothing good lasts forever

Hot (or rather, not so hot) on the heels of boasting of my many successful prints comes a tale of woe and sorrow! Woe! Sorrow! Or at least some technical problems.

While printing a faucet filter tool of presumably the right size for ours faucets (I was too lazy to measure), my white filament ran out. Supposedly, the printer should handle this nicely, running an unload procedure immediately. For whatever reason, it didn't, just letting the filament continue through until it was past the drive and thus the point of no return. Apparently, but I didn't know at the time, it's feasible to just feed in more filament immediately, but I tried re-running unload, then pushing the filament piece further down. To no avail, it was stuck.

Opening the side (which hinges up nicely), I found a lot of white debris (it had ground down the end of the filament). After vacuuming most of it up, this was the sight that greeted me:

Taking a closer look with my proper camera, it was clear that the filament sat in a PTFE tube and wasn't a giant blob or anything.

So I tried pushing some more, at higher temperatures, but it wasn't budging. Eventually, I had to take the hotend assembly out, and since I'd probably need to take out the nozzle anyway (one page suggested removing the nozzle and then heating), I would swap to my 0.8mm MegaNozzle shown below (banana for scale):

After getting a set of inverted hex bits (very useful!), it was easy enough to unscrew the nozzle, but that didn't help with the blockage. Fortunately for me, they had designed the whole thing so that taking out the hotend is relatively easy, and I was able to unscrew the heatsink and heatblock. They advice against unscrewing the heatblock, but I didn't see how to avoid it, since it's not really accessible. Anyway, with that out, I was able to heat it in the oven and carefully puuuull out the filament until it went "plop" and popped out. This was essentially the classic cold pull, though possibly a bit too cold due to not having the right tools right at hand at first. The PTFE tube needed replacement, but fortunately my kit came with two spares - how prescient!

So I reassemble the whole thing and run a test without filament - after all, I need a nozzle in there first, which requires 285C. Alas, the heating is bad - it heats up, but very slowly, at 100C about 1C per second. I didn't let it run for long enough to get up to full temperature, it took over a minute to get to 135C. To check that it wasn't the thermistor misreading it, I poked an old PLA print at the heat block, but it only deformed slightly, so it definitely wasn't doing runaway heating. That's something at least, overheating could be quite dangerous. But I'm still stuck with bad heating. I double-checked the wiring in the board, and the resistances and voltage were correct. So either there's a loose wiring in the heatblock end, or... something else.

A good, long service

One of the first complicated pieces I made, way back in early 2016, was a replacement foot pedal for one of our trash cans. Finally yesterday it met the end of its life, breaking off partway through:

Three and a half year of being stepped on multiple times a day is not bad, though. I shall give it a second chance using either epoxy or contact cement, but I'm proud of how well it held up.

In other news, the printer has had software issues after getting updated. The Display ETA plugin for OctoPrint was adding malformed text to the M117 commands, which made the printer reject it. Apparently plugins are not entirely harmless.

I also had a nasty crack in the extruder block:

This was causing the gears to move apart a bit and start skipping, the noise from which is how I eventually noticed. Notice how the crack follows the print, then follows the edge of the circle down to the nut trap (there's another nut trap on the left of the picture that the crack also went through). If I had printed for much longer, it would probably have fallen apart entirely. As it was, I was able to use good old-fashioned contact cement to extend its life:

I suppose one could actually pre-treat it with contact cement, to fuse the layers a bit better.

But it's not all doom and gloom. I haven't been keeping up with the posts, but that doesn't mean I haven't printed things. Here are a few of my successful outcomes:

I added some feet to a container in the bathroom, to avoid water collecting underneath (and to prevent sagging). I sprayed them with PlastiDip for extra stability and glued them on with contact cement. Disappointingly, when  I took this shot, I notic ed one of them was loose.

I printed a bunch of minifigs for our DSA campaign, several of which I painted. They must have been blessed, for the ambush we first employed them in went above all expectations - three shots took down three guards, the rest surrendered.

Team Green vs. The Red Rangers

Truth be told, my printer isn't nearly good enough for proper figurine printing. The heads are basically blobs with faint hints of facial features. I'm curious to try HeroForge, though it's expensive enough that I'll only do it for my own character, not a whole army.

I printed some new hangers for my plant pots, this time in white PETG, which should be more resistant to heat. Unfortunately, I forgot to mirror one, so now they hang kinda funny. And I only had a small sample of PETG, so I couldn't just reprint.

I'd previously made a base for our salt- and pepper-grinders, so they wouldn't dirty the table. But when moved, they had a tendency to fall off, so for safe-guarding during transport, I added the obvious thing - tentacles:

They were done by defining just one third-degree polynomium, which I then copied and rotated. It took some fairly arbitrary tweaking, but with only a single test print I got a usable holder. Does your kitchen have tentacles? If not, maybe it's time you ask yourself why not?

We have an extendable table from Ikea with a simple plastic locking system. Unfortunately, one of the lock parts fell out and disappeared, but printing a new one turned out to be quite easy:

And even earlier in the year, I made a sturdier version of the drilling guide for the magnetic poster sticks I had been wanting to make for years. This one worked. I'm still amazed that my printer can print a horizontal beam into thin air - the fan duct certainly helps make that possible, but still.

I'm slowly starting to consider replacing this old workhorse with a more modern machine that doesn't need as much care. Levelling is still a sore point - I have a probe mounted (as seen below) but not connected, I have nothing telling me when I run out of filament, nor if the motors actually move the amount I tell them to.

Finally, here's a small video of my machine at work, printing a test piece for a little holder in the kitchen. I like the sound of the movements, it's very futuristic. As is the ability to design and print useful pieces in your own home. We're truly living in the future.