MESS! Ugh. - Suggestions?

1

So I had a couple failed prints where the feed wheel would actually start to chew through the PLA. So I cleaned the inside of the tip (heat up/remove/repeat) to remove obstructions. I ran the extruder to make sure I was getting good melted filament through it. When I left - I ran the print, hoping it would be good.

NOT so good as you can see here.

  1. What the heck do I do with this mess? How do I remove this glob from the hot end?
  2. Whats my issue (likely?) I know you can’t say for SURE - but guesses? Why would it not feed sometimes and then do this? Thoughts?

Thanks,
Joe

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IMG_92513024×4032 1.81 MB
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IMG_92503024×4032 1.85 MB
IMG_9252
IMG_92523024×4032 1.94 MB

2

That looks like the part broke free of the build-plate and started getting drug around while the nozzle continued to extrude more filament.

This is probably a bed-adhesion problem.

  1. When the first layer is being applied to the bed, you want to filament to get a bit of a “squish”. Think of the filament like a spaghetti noddle. It’s “round”. If it stays round then only a very very tiny bit of the noddle is in contact with the build plate. But if you were to “squish” it in a little, then there is more surface in contact with the build plate and it will “stick” better.

  2. You didn’t mention which printer or bed type you are using. Commonly it’s PEI. PLA does a pretty good job of “sticking” to PEI as long as the bed is warm. When the bed cools, it should be a little easier to break free. It is usually not necessary to do anything more (no need for glues, hair-spray, or other adhesives if printing PLA directly on to a PEI bed surface that is “warm”)

  3. Use the right temperature on the bed. I find that it needs to be at least 55°C … but 60°C is good and you’ll commonly find people tell you to use a 60°C bed temp when using PLA. BUT… I found the factory profile when using PLA on my printer had it set to 55°C for the bottom layer… and then cooled the bed to 45°C for the rest of the layers. The cooling allowed the corners to warp up and weakened the adhesion to the PEI. When I stopped letting my build plate drop to 45°C (keep it at 55°C or 60°C) this issue stopped happening to me.

  4. If not using PEI… if using glass … then you need something to help with the adhesion (when using PLA). You can use PVA stick (Elmer’s glue stick is really PVA). PVA dissolves in water (which is why they let kids play with it… if they get it on their clothes it will completely dissolve in the wash – you don’t even need soap.) Some people use hairspray (e.g. AquaNet brand seems to be popular) but I dislike hairspray because the over-spray gets on everything else. There is a commercial adhesive & release agent called ‘Magigoo’. This stuff comes in a blotter-type bottle. It holds only about the same as Elmer’s glue (PVA) but once the build-plate completely cools … it’s really easy to remove the part (the product is more about the ease of release than how well it holds while printing).

PLA isn’t known to be nearly as bad as ABS when it comes to warping… but ultimately all materials can warp. So watch for that (edges & corners will pull free of the bed and lift up … but that means the print head can catch along the edges of the part and that might cause the whole part to break free.)

3

As for how to clean that up…

Well, I can only comment on how I’d approach that problem.

First, disassemble whatever you can of the print-head – remove the fans, and the plastic parts to which the fans mount. Use a twist tie to tie the fans to the top of the extruder, so that you don’t break the teeny tiny fan wires as you manipulate the hot-end.

Next, heat the hot end, ideally using one of those heat guns intended for spot heating (i.e. shrinking heat-shrink tubing or such). You want to get the plastic and metal hot, not the motor or fans or anything more than just that blue plastic.

Using tweezers and a very small set of wire clippers, start cutting away at the blue plastic. The technique should be to warm the PLA until it softens and becomes malleable, then use the tweezers to pull the warm soft plastic away – and once you have a blob pulled away, use the wire clipppers only if you must, in order to snip the plastic blob off.

The closer to the hot end you get, the more care you must use – if you pull out or clip the 5 wires connecting to the hot-end, you’ve got other problems. So use the heat gun and the tweezers, and patience. Don’t worry about a little left on the wires and such - it won’t hurt it (breaking the wires, on the other hand, will hurt it!).

Once you get the blue mostly off, you can start working with a small putty knife or the blue clam knife that came with the printer – just carefully scrape off the plastic from the heating block and the nozzle. Again, avoid the wires – the plastic near those wires is just going to have to melt and burn off as you use the printer.

You’ll end up with most of the blue plastic off – at which time you need to re-assemble the fans and all. Then mount it back, and give it a test. You should see the front fan turn on and run when the printer is powered up. You’ll need to manually turn on the side fan using Cura – and also using Cura, turn on the hot-end and warm it up.

The chances that you can get that cleaned up without breaking the wires depends a bit on how gunked up that side of the hot-end is… but I’d give it less than 50% chance. So, you can also proactively place an order for a new thermister and heating cartridge… and it might be easier to clean it up if you just cut the wires to those two components in the first place. Your choice.

(I guess there’s another choice – might be a good opportunity to buy a new print head – put the old one on eBay, someone will snatch it up for parts.)

4

Easy way to remove the rats nest is to heat up the hotend to 180 -190 and use a pick to remove the filament. Good chunks should come off the heat block and nozzle. Be careful of the wires, snip around if necessary… if you have a soldering iron, heat up the filament and remove.

5

Thanks all fof the replies! I did get it cleaned up, although I did damage some wires in the process. Bad part was, in ordering new parts the old hot end assembly was discontinued and while they had some “old” versions they were selling - they ran out or were on backorder. SO my options were to wait it out or to upgrade to the new hot end with an adapter (for my TAZ6) - and I didn’t have time to wait it out. We have seniors at the university doing capstone projects so I needed to be up.

Then I remembered when we moved our other TAZ to the dual extruder, I still had THAT OEM single extruder head assembly sitting the cabinet. I put it on this unit and its running very well. Many thanks!