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I've been going through the step by step for calibrating my extruder. I've got a very good, repeatable steps per mm. I've measured my filament diameter in several places, checked that it's actually round, and entered the correct diameter value in Slic3r. When I print the .5mm thin wall test cube, I can't get the wall thickness down to .55 without getting little voids and pocks in the layers once in a while. This also makes my solid fill cube with the same multiplier a little bit thirsty and underfilled.

What step am I not getting right? I'll post pictures tomorrow as I'm able.

Thanks!

Jimustanguitar wrote:I've been going through the step by step for calibrating my extruder. I've got a very good, repeatable steps per mm. I've measured my filament diameter in several places, checked that it's actually round, and entered the correct diameter value in Slic3r. When I print the .5mm thin wall test cube, I can't get the wall thickness down to .55 without getting little voids and pocks in the layers once in a while. This also makes my solid fill cube with the same multiplier a little bit thirsty and underfilled.

What step am I not getting right? I'll post pictures tomorrow as I'm able.

Thanks!

What layer height are you using?
Did you explicitly set the extrusion width or are you letting slic3r decide?

I'm printing .2mm high layers, my nozzle diameter is set to .5mm, and I've set my default extrusion width to .55mm.

Pictures of the failure would help.

Polygonhell wrote:Pictures of the failure would help.

I'll take some portraits

These are the voids I was referring to. I suspect that it's a temperature issue (see the white lines on some of the layers, is that poor adhesion?)

This cube is between .57 and .59 mm thick. My steps per mm are set as precisely as I think is possible (609 is the value mine needed), retraction is off, and my extrusion multiplier is .9

[img]http://i.imgur.com/1lbS50V.jpg[/img]

[img]http://i.imgur.com/iG6tTnj.jpg[/img]

Could be a temperature issue, could be bad filament aswell.
you're temporarily losing extrusion, or stretching the filament to much and it's snapping, have you checked your extruder nozzle is actually the right size, I think someone was saying that they shipped a number of larger nozzle diameters accidentally. If you have a 0.5mm drill bit you can use it as a pin gauge.

You also may want to try using KISSlicer as an alternative. It takes a bit to setup, but my prints have improved 1000% since switching from Slic3r. Maybe it's just me, but in Slic3r I was *ALWAYS* tweaking things to get a good print, and then everytime I printed a new object - I'd have to tweak a bunch more to get IT to print good. I was spending WAY more time tweaking than printing, it was very frustrating. With KISSlicer, it seems that my default settings work 99% of the time, it's just click-n-print. I rarely have to go back and adjust anything! It has made 3D printing fun again!

oeginc wrote:You also may want to try using KISSlicer as an alternative. It takes a bit to setup, but my prints have improved 1000% since switching from Slic3r. Maybe it's just me, but in Slic3r I was *ALWAYS* tweaking things to get a good print, and then everytime I printed a new object - I'd have to tweak a bunch more to get IT to print good. I was spending WAY more time tweaking than printing, it was very frustrating. With KISSlicer, it seems that my default settings work 99% of the time, it's just click-n-print. I rarely have to go back and adjust anything! It has made 3D printing fun again!

Can you share your settings? Are they taken from the seemecnc or johnoly99 github site, or did you come up with them yourself?

Thanks!

Thought about this earlier do you have randomize starting point turned on, if so try printing with it off.

I have voids exactly like those in your photo whenever I print higher than about 230. I really don't know what the exact cause is, though it could be extruder-related. I hear a popping sound whenever a new void is created, and it seems to be worse with my green filament, but I can't be sure of that. I can recommend lower temperature settings, however. That seemed to solve the problem for me.

I didn't know about the incorrectly-sized nozzle diameters. I'll have to see if I have any 0.5mm instrument strings laying around to check it with.

dsnettleton wrote:I have voids exactly like those in your photo whenever I print higher than about 230. I really don't know what the exact cause is, though it could be extruder-related. I hear a popping sound whenever a new void is created, and it seems to be worse with my green filament, but I can't be sure of that. I can recommend lower temperature settings, however. That seemed to solve the problem for me.

I didn't know about the incorrectly-sized nozzle diameters. I'll have to see if I have any 0.5mm instrument strings laying around to check it with.

Someone correct me if I'm wrong... But I'm pretty sure I've read before that the "popping" sound you hear during extrusion is due to moisture in the filament. I see it on mine too from time to time, I can also see little very brief puffs of steam as the heat causes it to evaporate.

I think the "pop" comes from the moisture that's captured inside the filament suddenly reaching a point where it can "escape" the filament as it leaves the hot end, and creates a micro-bubble coming out of the hot end similar to blowing a bubble with bubble gum. The popping of this bubble is what you're hearing

I do have randomize starting points turned off...

Still troubleshooting

texsc98 wrote: Someone correct me if I'm wrong... But I'm pretty sure I've read before that the "popping" sound you hear during extrusion is due to moisture in the filament. I see it on mine too from time to time, I can also see little very brief puffs of steam as the heat causes it to evaporate.

I think the "pop" comes from the moisture that's captured inside the filament suddenly reaching a point where it can "escape" the filament as it leaves the hot end, and creates a micro-bubble coming out of the hot end similar to blowing a bubble with bubble gum. The popping of this bubble is what you're hearing

It's usually either moisture or an air bubble in the filament.
There is a huge gap between good filament and usable filament.
I've helped a number of friends locally build printers, and I insist that the first roll of filament they buy comes from ultimachine, I them let them buy from where ever they want, most but a few rolls from eBay then just spend the extra because bad filament isn't worth their wasted time.
Having a known good roll of filament can be a huge help to initially tuning a printer.

Jimustanguitar wrote:I do have randomize starting points turned off...

Still troubleshooting

If you increase the extrusion width to 0.7 do you still get the voids?

Very interesting... If I slice the exact same thin wall test piece with Cura, I get exactly .55mm walls without doing anything to the multiplier. The odd variations in wall thickness are gone too.

I think I'm getting off the Slic3r wagon I've been fighting this calibration step for weeks.

As it turns out, the gaps in my prints were not the result of moisture or air bubbles, but delta-arm problems (again). My arms had been too loose, so I shimmed the U-joints a bit. Apparently too much, though. They were really sticking and I didn't realize it. So as the filament was extruding, the arms were jerking ever so slightly, occasionally snapping the filament.

dsnettleton wrote: I'll have to see if I have any 0.5mm instrument strings laying around to check it with.

I had a set of gauged welder tip cleaning wires laying around. I mic'ed the smallest few in the set and was able to confirm my nozzle diameter that way. A guitar string is a great idea too!