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Benchy: Is this a Slic3r problem?

Posted: Thu Jan 12, 2017 12:00 am
by Matt_Sharkey
So I got some new filament for a new project, Hatchbox PLA gray. I can't make odds of this defect on this Benchy and I think it's an inherent issue with Slic3r.
20170111_213255936_iOS.jpg
The artifact is a bulge noticeable on the bow 1cm from the bottom. I want to think that it is an issue with gap fill, but the area in question is mostly honeycomb. I have calibrated for z height, multiplier, temp, and retraction (in that order). relevent settings:

Diameter: 1.73mm
Multi: 0.99
Z offset: -0.28mm
Temp: 210-206
Bed: 60-60
Retraction 2.0mm @ 60mm/s
Z-hop: 0.1mm
height: 0.2mm
Width: 0.4mm
Perimeters: 3
Perimeter Speed: 80mm/s
Infill: 15% honey
overlap: 8%
Infill speed: 120mm/s
Accel: 800mm/s^2
Jerk: 10mm/s


Could anyone offer some advice perhaps? I will admit, I am a bit rusty and I lost most of my settings about 6 months ago, so I am re-configuring a lot here. What would be fantastic is if someone could run off a GCODE from S3D (with my calibration settings) of a Benchy so I could maybe commit to buying S3D.

Benchy: http://www.thingiverse.com/thing:763622

My Gcode of this print:
3DBenchy.zip
(942.11 KiB) Downloaded 107 times

Re: Benchy: Is this a Slic3r problem?

Posted: Thu Jan 12, 2017 12:42 am
by Jules
Too hot maybe? Looks a little melty to me....some of those PLA filaments will melt at absolutely nothing. (Also might want to increase the infill % and lower the infill speed.)

But get S3D anyway...it's so worth it. ;) :D

Re: Benchy: Is this a Slic3r problem?

Posted: Thu Jan 12, 2017 12:50 am
by ednisley
Matt_Sharkey wrote:it's an inherent issue with Slic3r
Doesn't show up on my Benchy, so it's most likely an issue with one of Slic3r's bazillion options.

That bar (looks like) it appears where the sloped front deck joins the flat(-ish) main deck. Step through the tool path preview and I think you'll find a bunch of solid plastic instead of the usual infill pattern.

Take a look at [Print Settings] → Infill → Advanced: Solid Infill Threshold Area. It's probably set to some absurdly large value: back it down to, say, 4 mm², re-slice, and look at the preview again. That should reduce the tendency to overload small areas with plastic; the change from normal infill to a solid slab generally produces a visible artifact on the perimeter.

Re: Benchy: Is this a Slic3r problem?

Posted: Thu Jan 12, 2017 1:04 am
by Matt_Sharkey
Jules wrote:Too hot maybe? Looks a little melty to me....some of those PLA filaments will melt at absolutely nothing. (Also might want to increase the infill % and lower the infill speed.)

But get S3D anyway...it's so worth it. ;) :D
I agree with the melty look, but I think my phone embellishes this look. I did a temperature tower and found that the layers delaminated at 200C but at 205 they broke perpendicular to layers, so I chose 205 and bumped it a touch.

will look into the infill settings.
ednisley wrote:
Matt_Sharkey wrote:it's an inherent issue with Slic3r
Doesn't show up on my Benchy, so it's most likely an issue with one of Slic3r's bazillion options.

That bar (looks like) it appears where the sloped front deck joins the flat(-ish) main deck. Step through the tool path preview and I think you'll find a bunch of solid plastic instead of the usual infill pattern.

Take a look at [Print Settings] → Infill → Advanced: Solid Infill Threshold Area. It's probably set to some absurdly large value: back it down to, say, 4 mm², re-slice, and look at the preview again. That should reduce the tendency to overload small areas with plastic; the change from normal infill to a solid slab generally produces a visible artifact on the perimeter.
Yeah threshold was at 70mm^2 so i pulled that down. off the bat I didn't notice dramatic changes in the Slic3r rendered tool-path but it may have subtly changed something else. I believe the solid slab mode you speak of is gap fill? and I also believe it is a known issue with more recent versions of slic3r that it over-stuffs these areas causing surface artifacts.

Re: Benchy: Is this a Slic3r problem?

Posted: Thu Jan 12, 2017 3:18 am
by Matt_Sharkey
20170112_021428872_iOS.jpg
The original issue is nearly gone with just the solid infill threshold reduced, Thanks Ed!

there is still a slight bulge that starts a few layers lower, right when the railing is started. maybe ringing? maybe the same gap fill issue?

next print is seeing if I can lower the temp to 200 and get a sturdy piece. low temp issues are exposed on single wall calibration cubes, but I'm curious if low temps are more acceptable when printing 3 shells, lets find out!

Re: Benchy: Is this a S̶l̶i̶c̶3̶r̶ S3D problem?

Posted: Sun Jan 15, 2017 3:29 pm
by Matt_Sharkey
Okay, I caved. I bought S3D a few days ago. Still trying to get this dialed in before the big project, I don't want any failures.

I'm having a hard time balancing the extrusion multi. In Slic3r I found the multi to be 0.99. I applied this to S3D and got a good benchy, but a bit over stuffed. so I calibrated and found it was overextruding. So I found S3D's multi to be 0.92.

Now is the frustrating part. I need a multi of 0.92 to get my 0.4mm single wall cube as desired. but then when I print anything with solid infill, it's too anemic and need more multi! WHATS GOING ON?!?!?

I really want to like S3D because it's solving all of the problems that Slic3r was giving me and only returned with a few of its own.

Halp!

Re: Benchy: Is this a Slic3r problem?

Posted: Sun Jan 15, 2017 3:48 pm
by zemlin
If I want a solid part in S3D, I set the bottom layers to 9999. Works better than 100% infill.

Re: Benchy: Is this a Slic3r problem?

Posted: Sun Jan 15, 2017 4:01 pm
by Matt_Sharkey
I was referring to top and bottom layers which are solid, I still use infill, but I care less about infill quality...
20170115_150201847_iOS.jpg
0.92 multi on left
0.99 multi on right

Re: Benchy: Is this a Slic3r problem?

Posted: Sun Jan 15, 2017 4:46 pm
by zemlin
Look at the Outline Overlap setting on the Infill tab. I think default is 10%. Might want to try increasing that.