Infill issues

[wcroft987 0]

Hello all,

I am having issues with my infill. The outer shell wall looks great, the solid first few layers print good to okay but the fill just turns to junk.

I have upped the infill overlap to 20% and the filament size to 2.8 when it measures around 3mm to up the filament out.

I am stuck and would appreciate any input. below is a flickr link to the pics of a few pieces that didn't turn out good.

http://www.flickr.com/photos/23320916@N06/

 

[gr5 2,240]

I'm pretty sure that's underextrusion. I can see it in what little you have of walls also.

There are many causes. You could have a bad feeder, a partial plug, filament diameter too large, printing too cold, or printing too fast.

1) A well tuned UM should be able to print about 10 cubic mm per second. The math is very simple on this - for example if you are printing 100mm/sec at .2mm layers (.4 width nozzle) then you multiply these 3 together (I can do it in my head it's so easy) and you get 8 mm^3/sec. This is close to the limit of what you can do if the filament is around 210-220C but relatively easy at 240C. So I guess the first question is what volume and temp were you printing at? Or if you can't multiple 2 and 4 you could just list the layer height and print speed.

2) If you are printing less than 4 mm^3/sec and temp is over 190C then there is some other problem.

3) Maybe your 3mm filament is getting stuck in the bowden tube - this is common for "bad" brands of filament. Especially since after coming out of the feeder, the filament has been squished a bit.

4) Maybe your feeder spring isn't tight enough - mine is at about 11.5mm when the feeder is closed.

5) Maybe the black wheel in your feeder isn't spinning freely or has a flat spot. Maybe you didn't close it tightly properly as shown in the famous(?) video that shows how your feeder should be used.

6) Maybe you thought you were printing at 240C but it was actually 160C because something is wrong with your thermocouple (this is actually very common).

 

[wcroft987 0]

I added another picture to the flickr link above. I found that the filament was clogging before the insulator and think i have fixed that problem.

The solid layers are printing good but the fill is still weird. The picture of the white latch is printed at 30% infill with abs.

 

[gr5 2,240]

Well it looks exactly like what I would expect if you printed at one speed and then did infill at a different speed. Set infill speed to 0 so that both speeds are the same.

 

[wcroft987 0]

Infill speed was set to 0

here is my cura setup

 

[gr5 2,240]

Try infill 20%. The infill algorithm changes drastically at 25% so I've been avoiding anything over 25%. When I want 100% I instead set the shell thickness to 200mm (lol) which works well.

 

[wcroft987 0]

I have figured out that it was my hot end, I broke my original insulator tube and bought a new whole hot end off eBay from China because it was cheaper. Needless to say it was very poorly made which was letting the PLA build up and clog (when the fill was printing )in the new insulator tube. After many iterations I came up with a new all metal hot end with active cooling which has fixed all my issues.

Thanks for your help gr5