strange bubbling issue occuring after 7th or so layer

[andysutils]

Hi Guys.

This has only just started happening recently. But on some of my prints after a few layers, certain parts of the prints start bubbling. On this one, it always starts to happen on the same place on layer 9 then just keeps doing that.<br>

Ive even rotated the print thinking it was a bed levelling issue but still happens in the same place same time.<br>

Is there a rule to the dimensions of an actual design you should avoid?

[Ama-fessional Molder]

What's the material, and do you dry it prior to printing?

It could be that the layers below build up in heat and the print head is dragging the deposition because the lower layers aren't cooling fast enough.

But that's just a guess on my part. I don't even have a printer yet.

Figured id at least let you know we're here.

[curious aardvark]

okay that is odd.

Not filament as areas on the same layer aren't effected.
unlikely to be calibration if the same areas are effected after moving.

So it's down to a design and slicing mix.

Given those parts are slightly wider than the rest I'd say it's an infill issue.
What slicer are you using. Also how wide are those parts and what diamater nozzle are you using.
Quite often if the width of a part isn't exactly divisible by the nozzle diameter, the slicer will use extra 'filling' between walls and that can effect the surface appearance.

I'd pretty much come down on design and slicer for this one.

So what infill settings are you using ? and how wide is the part and what nozzle diameter (and bead diameter - not usually the same, bead diameter is usually larger than nozzle diameter) are you using.

[andysutils]

okay that is odd.

Not filament as areas on the same layer aren't effected.
unlikely to be calibration if the same areas are effected after moving.

So it's down to a design and slicing mix.

Given those parts are slightly wider than the rest I'd say it's an infill issue.
What slicer are you using. Also how wide are those parts and what diamater nozzle are you using.
Quite often if the width of a part isn't exactly divisible by the nozzle diameter, the slicer will use extra 'filling' between walls and that can effect the surface appearance.

I'd pretty much come down on design and slicer for this one.

So what infill settings are you using ? and how wide is the part and what nozzle diameter (and bead diameter - not usually the same, bead diameter is usually larger than nozzle diameter) are you using.

Hi there mate.

Im using repitier host 1.6.1 for slicing and actually configuring my printer using slic3r.

my nozzle diameter is 0.4, im currently using the default extrusion width as 0.8 and the perimeters and ext perimeters are 0.8. Ive tried different ones but still more or less the same issue.

I re designed the drawing this time setting all the widths to 2mm but the drawing still ends up more less the same below.



The single perimeter prints I've done at 0.75 come out absolutely perfect as you can see below



below are my infill settings



Strange thing is, is it doesn't just happen with my design, it happens with every single print of similar diameter. Even the ones i download that other people have made

I really appreciate your post. Hope you can help.


Regards

[curious aardvark]

you're extrusion width is 0.8 !

Wow. that's pretty extreme.

Next time you load some filament. take your digital calipers and measure the extruded plastic's diameter.
That's what your extrusion width should be set to. With a 0.4mm nozzle it's usually between 0.4 - 0.55.
0.8 is just serious over extrusion.

[andysutils]

you're extrusion width is 0.8 !

Wow. that's pretty extreme.

Next time you load some filament. take your digital calipers and measure the extruded plastic's diameter.
That's what your extrusion width should be set to. With a 0.4mm nozzle it's usually between 0.4 - 0.55.
0.8 is just serious over extrusion.

Its only been set to 0.8 since yesterday as i read somewhere it should be double your nozzle,... which i thought was strange. Before that ive always had it at 0.5 but still have same problem at 0.5 and even at 0.54. I set it to 0.4 still have the same problem im afraid

I did all the caliper stuff on a 10cm length. I did the cube test print and it does come out at 0.98 to 1mm exactly.

I will try 0.55 and some lower settings

[Ama-fessional Molder]

you're extrusion width is 0.8 !

Wow. that's pretty extreme.

Next time you load some filament. take your digital calipers and measure the extruded plastic's diameter.
That's what your extrusion width should be set to. With a 0.4mm nozzle it's usually between 0.4 - 0.55.
0.8 is just serious over extrusion.

That's what I was wondering. So to ask the question here, since we are on the subject:

Is the extrusion width the width after it mushes out during deposition, or the raw width. I would assume it's the former, which would make sense in order to accurately estimate the finished size. On that logic, .8 would mean .2mm of "mush" on either side, and that doesn't seem extreme....


Buttt I know better, and actual results should be a function of travel/print head speed, extrusion speed, layer height, nozzle diameter, and filament diameter, correct? If I am missing a variable, please fill me in.

[andysutils]

I think ive found the problem.

on my small drink stirrer handle. I set the extrusion width to 0.55 and it prints perfectly now.

However, with the same setting of 0.55 the same problem occurs on later 5 on the other larger stirrer i got from someone else.

I turned the flowrate of my extruder down to 80 and the problem still happens but on around layer 7

I then turned the flowrate up to 125 and exactly the same identical problem starts to happen around layer 2-3

It appears my filament is not flowing consistently. Does this sound like i am correct? if so, what can I do to troubleshoot and fix?

[curious aardvark]

sounds like you're messing about too much.

You NEED TO MEASURE the unsmushed diameter of the extruded filament - NOT guess it.

The reason for this is simple - the extruded width of the filament is the measurement that EVERY other calculation is based on.
Get it accurate and everything else works better.
Extrusion - I've always had it at 100% - but I measure my extruded filament :-)

What filament are you using and what temp are you extruding at - also what speed are you extruding at.
Temp and speed have a greater effect than extrusion %

The thing is, every make of filament has a sweet spot where temp and print speed meet and have sex and give birth to lovely printed children.

So it's easier to measure your extruded filament, set extrusion to 100% and adjust flow with temp and print speed.

The slicer is working off the right calculations so extruding the right amount of plastic. get the flow rate right and everything else should fall into place.

[andysutils]

sounds like you're messing about too much.

You NEED TO MEASURE the unsmushed diameter of the extruded filament - NOT guess it.

The reason for this is simple - the extruded width of the filament is the measurement that EVERY other calculation is based on.
Get it accurate and everything else works better.
Extrusion - I've always had it at 100% - but I measure my extruded filament :-)

What filament are you using and what temp are you extruding at - also what speed are you extruding at.
Temp and speed have a greater effect than extrusion %

The thing is, every make of filament has a sweet spot where temp and print speed meet and have sex and give birth to lovely printed children.

So it's easier to measure your extruded filament, set extrusion to 100% and adjust flow with temp and print speed.

The slicer is working off the right calculations so extruding the right amount of plastic. get the flow rate right and everything else should fall into place.

If you ever consider buying another printer, please let me know because im bloody paying for it.

You're genius. I just tested my project measuring the extruded filament at 0.58 and so far, its printing flawlessly.

Massive help buddy. Many thanks, I will let ya know if I have any more probs but fingers crossed, so far so good