Small gaps in prints (and general advice please)

[PhoenixNZ]

Hi All,

Apart from the fan shrouds these are the first two things I've printed and I have a couple of questions as a 3-D printing noob.
They're both low-poly Pokemon from Thingiverse because nostalgia and because the parts were 100% made to print.

Both of these were printed at 50% speed
My hotend consistently reads 10°C lower than the setpoint. I suspect I need to insulate the metal section below the PEEK but I would have to dissasemble the entire hotend to do so
The hotend struggles mightily to get to 225°C and sometimes never makes it there while the PEEK fan is going which is why I decided to try out PLA instead

EDIT: For those who can't see the images properly: http://imgur.com/a/UGEUx

First up is the Bulbasaur in black ABS.
[img]http://i.imgur.com/tueDzfX.jpg[/img]
Apart from getting a little melty at the top I was really happy with how this turned out. I used the default (ones from the manual) Slic3r settings and Repetier Host 1.0.
It took two goes to get the print to start and adhere to the bed (first time the bit of ABS dangling from the hotend curled up and caught on itself). Not sure if this happens often?
I noticed there are a bunch of tiny gaps in the layers - does not look like layer seperation but more like random missing bits of filament.
[img]http://i.imgur.com/mlVaQ9Q.jpg[/img]


The second print was Pikachu in black PLA. Again: default settings in Slic3r using the .ini linked in the manual

From looking around the forums I think I need to decrease the hotend temperature to help with the stringing, maybe increase retraction speed etc.
The little gaps in the material are more pronounced on this model (even if it is hard to see due to the gloss finish and my potato camera)
[img]http://i.imgur.com/O1U9UMp.jpg[/img]
[img]http://i.imgur.com/OHKiuSw.jpg[/img]
[img]http://i.imgur.com/kvImi5N.jpg[/img]

[PhoenixNZ]

Just a thought that I can use to bump:

Is the small gaps in the print due to "under extrusion" I've heard the term used before but don't know how it reveals itself in prints. Are my filament diameter settins wrong, or maybe I need to up the extrusion speed or speed in general?

[lightninjay]

Sadly, some of what this could be is quality of filament. If the thickness of your filament varies too much, the solid stream of molten plastic coming out of the hotend will vary as well.

What brand of plastic are you using?

[PhoenixNZ]

Oh, well that's no good to hear. I did notice there was a lot more variation in my PLA than the ABS when measuring diameter with a micrometer.

I'm based in Australia so am using BilbyCNC filament. Might just have to try a different supplier next time.


Is it normal for a printer head to just ooze out filament when idle? I'm guessing it's kinda like using a hot glue gun and is the result of filament expansion or the effect of having the extruder driving filament into the hot end from so far away. I've also noticed that even though the default settings ask for 2 or more perimeters, the filament does extrude through the hot end and affix itself to the heated bed often until halfway through the second perimeter.

[lightninjay]

My nozzle oozes in much the same way you describe. I usually run a few centimeters out of my nozzle just before I start a print (after everything is all heated). Usually this helps prime the plastic coming out and make sure it's flowing free to get a better stick on the first few passes, making dang sure that it'll stick on the actual first layer of the print.

One possible solution could be to slow your prints down a bit (75% or maybe even 50% speed) and see if that has any improved effect on quality. As for the stringing effect, you may try lowering your extruder temperature anywhere from 5-10 degrees Celsius.

[teoman]

Would you mid cropping your pictures as much as possible from now on. I can not view them on my mobile device. They are not clickable and I mostly see your table with just the corner of the print showing.

If you are using apple preview can do it. Cmd + K.

[PhoenixNZ]

Would you mid cropping your pictures as much as possible from now on. I can not view them on my mobile device. They are not clickable and I mostly see your table with just the corner of the print showing.

If you are using apple preview can do it. Cmd + K.

Hi Teoman, sorry didn't realise it showed up funky on mobile. try looking here:
http://imgur.com/a/UGEUx

OP updated

[PhoenixNZ]

One possible solution could be to slow your prints down a bit (75% or maybe even 50% speed) and see if that has any improved effect on quality. As for the stringing effect, you may try lowering your extruder temperature anywhere from 5-10 degrees Celsius.

Thanks for the advice. I'm pretty sure I had both prints set to 50% speed. Will have a play with the temperature settings though

[teoman]

Try increasing retract by 2mm.