underextruding, but only around circles?

[jason128]

This has had me chasing my tail for several prints...

extrusion settings look good, apart from around holes/ circles, where they always separate as in the picture

running at slow speeds 30mms
.6 nozzle
ABS at 245

using Simplify 3d, but dint think that makes any difference.

Any ideas greatly appreciated.

[joe]

You could try increasing the overlap extrusion percentage.

[Nylocke]

What is your extrusion width set to? It should be around 110% of the nozzle diameter. What hotend are you using?

[rubiks24]

What is your extrusion width set to? It should be around 110% of the nozzle diameter. What hotend are you using?

Could you explain why the extrusion width should be set to 110% of the nozzle diameter. What are the benefits of this as compared to 100% width? Doesn't the slicer just automatically calculate how much filament to put down and also how wide the parts are?

[Mac The Knife]

What is your extrusion width set to? It should be around 110% of the nozzle diameter. What hotend are you using?

Could you explain why the extrusion width should be set to 110% of the nozzle diameter. What are the benefits of this as compared to 100% width? Doesn't the slicer just automatically calculate how much filament to put down and also how wide the parts are?

Could you explain why your nozzle is .6mm? SeeMeCNC sells .7, .5(stock), and .35mm nozzles.

[jason128]

Cheers for the prompt replies.

i'm running a e3dv6 with a .6 nozzle, and the extrusion width is set to auto in S3d - so .72 for a .6 nozzle or 120%... i will try pulling this down to 110% percent and see if there is any difference.

I dont think there is a "overlap extrusion percentage in simplify 3d. there is a overlap percentage for infill, but that is where the infill overlaps into the perimeter, whereas i have issues only around holes. its fine on straights and corners?

[Nylocke]

I use KISS and it asks me to specify line widths. The 110% number came from the older RepRap days, I've just had the best results with this IME. The slicer does calculate how much material it needs to extrude, but it needs a width and height for the trace to calculate volume.

Was that the top of the part? It looked like it was, kinda looks like you're under extruding a slight bit. If you aren't outputting enough material/it isn't hot enough to bind well it can increase the "short cut" effect (where the filament tries to take the most direct (eg straight) path it can, which pretty much means holes will almost always be undersized a bit)

[Jimustanguitar]

I've heard this blamed on mechanicals with slop and lash in them before, but I'm convinced that S3D must calculate their infill overlap differently than other slicers. I have to crank that setting way up to get the same results as other slicers with much lower numbers, and I've got a nice tight machine. I use 15 or 20% in Cura, and to get the same results I have to do 60 or 70% in S3D. I wonder if the normal slicers calculate the overlap distance from the center of the extruder nozzle and the S3D math uses the edge of the extrusion width instead. That's how I've explained it to myself, at least. It would explain needing to have the settings about 50% higher, since it's measuring 50% farther away from the point that other programs use...

I also seem to remember that it was a difference that people started to notice between versions 2 and 3. I don't know if that's right or not, but the version 3 release thread is where my search results lead me.

[jason128]

Thansk for the replies.
i have my suspicions that this silver ABS might be a little more temperamental than others, and not flow as well.

Finding a good Filament supplier in New Zealand seems near impossible. I would happily pay a premium for good stuff, but cant find anyone stocking anything half reasonable.

will let you know when i find an answer

[Nylocke]

Grey, silver, and white materials always have weird fillers and colorants to get them to be that color (ABS is off white and very slightly translucent normally, the white stuff becomes almost chalky and the grey stuff seems to be about the same. This is true even for more premium suppliers (eg Ultimachine)) I've never had a good roll of filament in any of these colors of ABS. White Ultimachine PLA seems decent (from what I have printed with it), though.

[jason128]

I finally managed to get this issue sorted- upgraded to the ball arms

i think it was a combination of a little slop, crappy ABS, and slicer settings.

In the slicer settings i ended up slowing up the default speed, and bring the perimeter up to 100%. not the speeds are pretty much consistent through the print, and hence less variation.

hope this helps anyone else chasing the same issues