Holes in my prints!

[aaroncm]

Hey guys,

I've been having an issue with my printer for a while now, basically, from what I can gather, my bridging ability is terrible!

Printing with 20% infill, the bridging over the top of the infill when it reaches the top of a surface, is bad, and by the time it's completed printing the surface over the infill, there's holes. There's also beautiful flat spots, but usually a fair few holes and cave ins.

I've also noticed that when it's printing infill, usually a diamond pattern, there can be a few spots where the 4 support walls intersect where one of said walls won't join. See here: http://cosketch.com/Rooms/ywdfxow

And one more thing I can see, is sometimes the outer visible walls of a final print have distortion.

I've tried a few spools of ABS I have, all 1.75mm. I've been using the latest version of Cura, with a perfectly level bed. I've tried different extrusion multipliers. I'm using a Bulldog Lite and the Steps/mm are (I think) 107. I've tried different temps, bed temps, speeds, etc. I can't figure it out. When I try to do bridges that are around 10mm wide, it's really really bad. Oh, I've also tried slic3r and Pronterface, still no luck.

I've had the printer for a few months now, and I've been working on it ever since making it better and better, I love it but I'm starting to wonder if I've always had this issue, because only now have I started printing things where this issue could be seen. Except for the infill, I don't remember noticing the effect I'm getting now.

Any information you guys can provide regarding this is appreciated, if I've left any missing information out, let me know!

Thanks!

Edit: Just to add, it's a Prusa i3 build, and I'm using a Bowden setup with an E3Dv6.

Another Edit: Here's an image of bad external walls: https://www.dropbox.com/s/su0r8lx2n4...%20pm.jpg?dl=0

[-willy-]

It looks like your material may have absorbed water. How do you store your filament after opening it from the package new? Have the prints been slowly getting more worse with time?

It will help others when they answer to know : where you got the filament. Printing temp and so on.

[aaroncm]

It looks like your material may have absorbed water. How do you store your filament after opening it from the package new? Have the prints been slowly getting more worse with time?

It will help others when they answer to know : where you got the filament. Printing temp and so on.

Thanks for the reply.

The filament I used is around two months old, I also have two other rolls, all being ABS, being probably 2 and 4 months old each. I've tried all three and they seem to behave the same. I've been storing them in open air, the humidity isn't that high though. Also sorry, I've got all my rolls from various places, I couldn't really tell you!

I've known that ABS absorbs air moisture and degrades, but does it really happen that rapidly that it could be the cause of my problem?

It does crackle and pop as it comes out, too. Hmm...

Only other cause I thought was incorrect temps, so I ordered an IR Temp Beam Sensor, but I think you might be right.

I have to ask though, for my next roll, I might get PLA. Does it suffer from the same issues?

Thanks.

[-willy-]

PLA from what I understand is worse than ABS. I havent started printing yet and my knowledge is only from what others have written.
The understanding I have to how to store filament ranges from keeping filament in vacuum containers (requires an airpump drawing down the container) to a 5 gallon pail from home depot (with lid). The 5 gallon pail is what I am leaning toward. It involves making an air tight mount and mounting a light socket in the top of the can. The idea is (even the energy star bulbs will) that a light bulb will create some heat. To enclose up to two spools in this container with the light slightly heating the chamber 24/7. Tried to find the youtube vid of this yet I cant find it anymore. But you get the idea, use low temp heat to dry something in a container.

Yes hearing the popping/crackling noise from the extruder makes me think water.

this vid says to use some of those crystals that come with stuff that gets shipped.

On a side note. Arc weld rods need to be stored from moisture as well. They usually get a apartment/dorm type fridge also with a light bulb inside. The fridge part isnt used except for the airtight door. A light inside to gently warm the air. The difference to above is that the fridge is insulated and doesnt allow light to permeate the plastic.

Hope this info helps.

[3DPBuser]

Might also try PET, it does not absorb water at all.

[Marm]

I did a little research on this a while ago, I don't have the link anymore, but a siimple google search will answer most of your questions. I do have a graph that shows ABS absorption rates.

Basically, ABS will almost reach equilibrium with the ambient humidity in little over 24 hours. It will be at about 30% of the humidity in around 30 minutes, so in even short term exposure to high humidity environments is not good for ABS. That data is based on pellets, so it will different for filament. As the SA/V ratio is less on a filament that a pellet, those absorption rates will be a little lower.