1

Hey Guys, I am printing with my XYZ Da Vinci Junior and when printing it seems to be skipping layers or something is wrong. When the print finishes you can stick your fingernail in certain sections and pry the part right in half. How do I stop this? It was printing perfectly fine before and the parts were solid and could not split in half.

2

Hey!

Can you post some pictures of what’s happening? It could be several issues, and pictures would really help!

Also, is this printer a Bowden (tube feeds filament into the hot end, but the extruder motors aren’t physically part of the hotend) or is it direct drive?

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Sorry, I’m out of town when I get back I can post some. But The filament goes up through the motors and through a tube and it the extruder. There is no filament feeding motors in the extruder. They are at the other end of the tube.

4

So you definitely have a Bowden style printer on your hands! Your issue could be happening for a couple reason, but, since this is a new issue you haven’t had in the past, I doubt it’s related to extrusion temperature or layer height (the obvious ones).

Is this happening with PLA filament, and has this filament been left out in the open air? If yes, you might have some water damaged PLA on your hands. PLA is fairly hydrophilic, meaning it will sucks up water from it’s surrounding environment including water in the air. The moisture that gets trapped inside the filament then turns into steam as the plastic gets hot, which interferes with the flow out of the hot end of the printer. Uneven extrusion means weak prints and gaps in the walls of the model.

I’d also suggest checking to make sure the nozzle isn’t clogged (also leads to inconsistent extrusion) and that the extruder isn’t skipping as it prints. The skipping happens when the filament drive shaft can’t get a good grip on the filament (which happens for several reasons) or because it’s feeling too much resistance from the hot end (usually due to a clogged extruder or dirty feed tube). If you think your drive shaft is slipping you have a few options:

  • Try cleaning it with compressed air (focus on the grooves that pull the filament) and see if that helps. As the little grooves that are cut into it get more and more clogged with filament dust and dirt from the environment, it has much more difficult time getting a good grip when printing. It’s like how a car tire loses traction if the treads are filled with mud or rocks.
  • If cleaning with compressed air doesn’t get rid of all the gunk, you will have to take it apart and really clean it well. Wire brushes and solvent work well for this (just be careful using solvents). While you have it apart, I’d suggest vacuuming out the feed tube for the filament as well. This tends to get gunked up as well and can leave debris behind in the nozzle which will lead to a clog.
  • If any form of cleaning helps nothing it may be time to replace the drive shaft. Try everything else before doing this!
5

Sounds like under extrusion. Can you hear the extruder motor click?

6

Just one wild idea to add - as I have a DaVinci Jr. too. I’ve noticed that the more recent client software has a choice for nozzle diameter which can be set to .3 or .4 mm. My unit has a .4mm nozzle, but I doubt if the software can confirm this with the machine. If you have it set for a .4 and it really is a .3 then you’d get underextrusion as you have experienced. Your extruder head might be marked in some way to identify the nozzle diameter.

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I am sure it is a .4 diameter which I have it set to.

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I used to have motor clicking but I changed my Z axis a while ago and was printing normal.

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I will try all of those but I think the PLA might have water in it then. I had left it out for about 3 weeks. How long before it absorbs water? How do I reseal it?

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There are a lot of variables on moisture uptake but temperature and humidity in the air around the material is critical. Check this blog for some simple ideas to dry out and even store your filament:

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It really depends on your environment and where the PLA is kept in your house/shop. I live in New York, which isn’t tropical, but my printers and all their supplies are kept in a shop which is really humid almost all the time. If I left PLA out for 3 weeks, I’d definitely have issues with it (and have had issues in the past).

The first thing you can do is dry it out in an oven at around 170 degF for a couple hours. Keep an eye on the filament during this process; if it’s on a black spool parts of that may get hot enough to start melting the PLA. If you don’t have an oven that can be set that low or are worried about melting it, you can also put it in a fridge for a few days (just not in the veggie or fruit drawers).

Once you dry it, there are a couple of storage options to prevent it from getting wet again; you really don’t want to dry it more than once in an oven because you risk messing with the material properties of the plastic. There are a couple of storage options out there; I use a weather-seal Ziploc bin with an Eva-Dry dehumidifier in it because of how much filament I have. With smaller amounts of filament, you can use the vaccum-seal storage bags or Rubbermaid containers and put a few packets of desiccant in each one with the filament. Desiccant is what’s in those little packets that come with the filament. If you Google silicon desiccant packs, you can get them on Ebay or Amazon for pretty cheap.

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Thanks I’ll See if that fixes it.