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Infil looks bad, all prints bad what happened?

Posted: Tue Dec 17, 2013 10:57 am
by truenorthtrader
Based on this picture can anyone tell me what is wrong?
The grey filament is from the same place ( Voxelfactory ) as the white, the grey one is not filling in, filament seems thinned out.

Seems when I updated the newest firmware I've been having worse and worse problems.

Only perimeters turn out great.
I'm using the J-Head as the stock Seemecnc was leaking too much ( got my Rostock Max in the Kickstarter ).
Used same J-Head on both white and grey prints.

I've recalibrated, redone PID, took extruder apart and re assembled, checked cheapskates, belts, everything possible nothing is changing. Printed this grey item at 218, 225 and 229 degree's. all the same.

many thanks in advance
A
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Screen Shot 2013-12-17 at 10.57.57 AM.jpg
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Re: Infil looks bad, all prints bad what happened?

Posted: Tue Dec 17, 2013 11:23 am
by MSURunner
Looks like the grey filament is either slightly smaller in diameter or has a slightly different flow characteristic. I'd try lowering the filament diameter a little bit and seeing what happens.

Re: Infil looks bad, all prints bad what happened?

Posted: Tue Dec 17, 2013 11:43 am
by Jimustanguitar
The problem is that there's only one pick of destiny. You simply cannot have two :)

Re: Infil looks bad, all prints bad what happened?

Posted: Tue Dec 17, 2013 11:46 am
by 0110-m-p
Jimustanguitar wrote:The problem is that there's only one pick of destiny. You simply cannot have two :)
And answer of the day goes to...

Re: Infil looks bad, all prints bad what happened?

Posted: Tue Dec 17, 2013 11:51 am
by truenorthtrader
LOL Jimustanguitar! :D :D :D

Thanks MSURunner I'll do that now! I measured with my digital caliper and averaged I'll lower it and reprint.

Re: Infil looks bad, all prints bad what happened?

Posted: Tue Dec 17, 2013 12:16 pm
by MSURunner
Keep in mind, too, that different dyes can affect the PLA and it's flow characteristics. It's not uncommon to have to change the flow setting/filament diameter to match different colors of filament.

Re: Infil looks bad, all prints bad what happened?

Posted: Tue Dec 17, 2013 6:04 pm
by truenorthtrader
Ok reduced to 1.8 from 1.9 and upped the temp to 230
A minor improvement ie check over the nose area but still odd.
Perimeters always look great.

I'm wondering if the j-head has such problems I've been using it
A few months now.
image.jpg

Re: Infil looks bad, all prints bad what happened?

Posted: Tue Dec 17, 2013 10:24 pm
by MSURunner
That has the appearance of a slicer issue to me. Which slicer are you using? Slic3r, when mandating a set extrusion width, doesn't have the ability to fill those gaps where it cannot create another loop. KISSlicer and Cura both have features built in to fill those "thin wall" issues. I think you need to reduce your filament diameter a bit more, though, looking at the solid infill for the face and the fact it's not connecting the infill to the perimeter loops. I cannot speak for 1.75 mm setups, but 3 mm filaments, particularly PLA, generally measure in at 2.8-2.9...

Re: Infil looks bad, all prints bad what happened?

Posted: Wed Dec 18, 2013 12:52 pm
by truenorthtrader
MSURunner looks like you were right! I put it down to 1.6 and this is the result! Might back it off to 1.65 or 1.7 as it's a little blobby but filled!

I just hope my nozzle doesn't squash my prints I still have that problem when they get higher
thank you again so much, you hit it right on the head!!!

Hope this helps other people with the problem, I never would have guessed colored filament make such a difference
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Re: Infil looks bad, all prints bad what happened?

Posted: Wed Dec 18, 2013 1:31 pm
by MSURunner
Sweet! I'd say 1.65-1.68 will do the trick looking at your pic.

Re: Infil looks bad, all prints bad what happened?

Posted: Thu Dec 19, 2013 3:15 am
by altarke
I am happy this issue was solved, but I am very curious as of what it is that you look for to know it's a filliment dia issue?

Re: Infil looks bad, all prints bad what happened?

Posted: Thu Dec 19, 2013 1:30 pm
by Lochemage
altarke wrote:I am happy this issue was solved, but I am very curious as of what it is that you look for to know it's a filliment dia issue?
What you're actually supposed to do is use some calipers and measure the thickness of your filament, then use that value. Depending on the manufacturer etc, you're filament will vary in actual diameter size compared to the written size. What most people do, though, is they do some test prints and see whether the lines need to be a tiny bit thicker or thinner, and then change the filament size value (even if the filament isn't actually that size) so the printer is 'fooled' into thinking it is getting more or less filament per mm and will compensate by making all extrusions a bit shorter or longer.

Ideally, using the exact sizes and perfectly calibrated step sizes should be perfect, but IME it doesn't always work out that way.

Re: Infil looks bad, all prints bad what happened?

Posted: Thu Dec 19, 2013 1:36 pm
by MSURunner
altarke wrote:I am happy this issue was solved, but I am very curious as of what it is that you look for to know it's a filliment dia issue?

Assuming the extruder has been calibrated at least somewhat closely for steps per e, then you are looking at the volume of the material extruded. When you look at some of the earlier pictures, the infill doesn't touch the perimeters in any location and it's not touching itself when combing back and forth. If it was touching in one direction, but not another, and the top combing was touching in places other than the very ends I would be inclined to believe that a pulley was slipping/belt tension was off in the positioning of the head. It's important to note that the various formulations for PLA/ABS have different flow characteristics, that while similar, have some subtle differences. Just because a filament measures 1.75 or 2.9 or whatever, doesn't mean that entering that into the slicer's filament diameter will produce the desired result. Lots of filaments are not perfectly round, and the packing density of the filament changes depending on the temperature and speed with which it was created. You can try to tweak flow settings if you want, but changing the filament diameter does the same thing mathematically as the flow setting when slicing. Flow setting should usually only be changed mid print, IMHO, to try to dial in the filament diameter to give the slicer.