PLA curling up from bed

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Dale Reed
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Location: Cleveland Heights, Ohio USA

Re: PLA curling up from bed

Post by Dale Reed » Mon Apr 21, 2014 2:10 am

sprior wrote:Interesting, I never changed the extrusion width setting to manual (0.35), but when I just changed it to auto the value changed to 0.42.
sprior,

I just started a print of an old model. Before I kicked it off, I noticed that my extrusion width got changed at some point from Auto (0.43) to Manual at 0.35. I suspect it happened when I loaded my 2.0.1 S3D FFF into 2.1.0. Did you upgrade recently?

Glad I caught it, because this print is turning out just STELLAR. First layer is just dead nuts on. If this one comes out as well as it's starting, I may have a nifty six-block puzzle picture to post on the Show-Off-Yer-Stuff subboard!
Dale

sprior
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Re: PLA curling up from bed

Post by sprior » Mon Apr 21, 2014 2:21 am

I only purchased S3D a couple of weeks ago so I'm not sure I've ever run version 2.0.

I'm finding some aspects of this software a little quirky to use, you start off with defaults for your printer and then once you change anything those settings get saved and there is no obvious way to get everything back to the defaults or tell what settings aren't the default. So if you have a specific model that needs tweaked settings it's tricky to get back.

I'd very much like to know what the effect of the Extrusion Width setting is. If the setting means how thick the line is extruded for a given amount of plastic, then if the value is set low then I'd think it would have to draw the lines more tightly to compensate which effectively would cause over-extrusion. But that's a guess on my part.

sprior
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Re: PLA curling up from bed

Post by sprior » Mon Apr 21, 2014 2:30 am

I just checked my wife's laptop which has S3D 2.1, never had 2.0 and only just used the first time today and sure enough the Extrusion Width was set to manual by default.

sprior
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Re: PLA curling up from bed

Post by sprior » Mon Apr 21, 2014 2:57 am

Just for giggles I just prepared a big model for printing in S3D changing nothing between runs except for the extrusion width value to see the resulting material difference:

auto 0.42:
build time 1233.86 min
filament length: 78268.2 mm
material cost: $10.82

0.35:
build time 1412.81 min
filament length: 75901.7 mm
material cost: $10.50

So it seems that the 0.35 value I was accidentally using results in less filament than the apparently correct auto value of 0.42. Don't know if this has anything to do with the curling problem I've been seeing, but if anything I've been under-extruding, not over.

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jimc
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Re: PLA curling up from bed

Post by jimc » Mon Apr 21, 2014 3:03 am

you can get the default process back. in the profile name box hit the down arrow and choose makergear m2. the thing with s3d is there is alot more there than meets the eye. there are many ways of setting and doing things that arent really apparent. you might use it for a few months and all of a sudden see something or realize there is something there you can do that you never even noticed before. the extrusion width is the width of the line that you put out. now a .35 nozzle doesnt actually put out a line thats .35. as jin said before it needs to be squished out atleast slightly for proper layer adhesion. i believe i saw on the makergear site that the .35 nozzle has an actual extrusion width of .42 which is just where s3d has it set now for the auto feature. if you go less that that you CAN start to get unusual things happen. infill looks broken apart, etc.

as for the funny look to the outside of the model, that is pretty much normal when a print curls up because the nozzle is touching or almost touching the model and the extra plastic is squeezing out the side.

it could very well be that you are under extruding. as for the first layer adhesion, that layer is most important. you should have 100% surface contact of plastic to build plate. if you pull your part off the bed and look at the bottom you should not really see any lines.

Toby
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Re: PLA curling up from bed

Post by Toby » Mon Apr 21, 2014 3:30 am

I just printed 3 versions of a 40mm x 40mm x .5 mm square. Each at layer height .25 and 50% infill with no top or bottom layers and 4 perimeters. The first had the manual extrusion at .25, the second at .35 and the third at .45.

My camera can't pick up the differences, but they are easy to see looking at them. First of all is the obvious thing that the larger the number, the thicker the perimeter. The not obvious thing is that the lower the number the denser the 50% infill appears. This sort of makes sense since it's printing thinner lines closer together, so it may appear denser to the eye. But it could have a practical impact on printing if the thinner lines aren't really as thin as they're supposed to be and so run into each other and build up plastic.

Bottom line is it looks to me like the .45 print was the one that was closest to the what the other settings were aiming at printing.

sprior
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Re: PLA curling up from bed

Post by sprior » Mon Apr 21, 2014 3:42 am

I just found that in S3D if you have the Extrusion Width set to auto and then select a different printer model it changes to a manual value, then when you change back to the original printer you still keep the manual value.

Oops.

Toby
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Re: PLA curling up from bed

Post by Toby » Mon Apr 21, 2014 3:54 am

sprior wrote:So it seems that the 0.35 value I was accidentally using results in less filament than the apparently correct auto value of 0.42. Don't know if this has anything to do with the curling problem I've been seeing, but if anything I've been under-extruding, not over.
from the test I just did it seems plausible that at .35 the perimeter lines were closer together, but if the plastic coming out was actually more like .42 mm wide, they could be bunching up and producing the effect you saw. just guessing though. the only way to tell for sure is to reprint.

jsc
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Re: PLA curling up from bed

Post by jsc » Mon Apr 21, 2014 3:55 am

I think what you are seeing is that the preset for the M2 has the extrusion width set to 0.35. When you change a value, that doesn't really change the preset, it only changes it for future prints using the last used process setting. If you manually select something from the drop down, ever, without saving the previous settings when it prompts you, those settings are lost in time, like tears in rain.

The solution is to export your chosen settings and use that .fff from the drop down. Better yet, open up the FFF in a text editor and manually populate all the materials and quality sections as I detailed in another thread, so you can change materials and layer heights/speeds without using a separate FFF for each setting (if you just use the export button, it only exports the material/quality you have chosen).

I attach here my own default settings file, which I generally tweak for each print anyway, which has been modified as suggested above.
Attachments
MakerGear M2.fff.zip
(2.41 KiB) Downloaded 79 times

sprior
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Re: PLA curling up from bed

Post by sprior » Mon Apr 21, 2014 4:00 am

I agree it looks like there is a manual setting for the M2 which has a value of 0.35, but the "auto" value is 0.42 and possibly the more correct value. I see the value in the file you sent me is 0.40.

I just kicked off another print of the yellow model I had pictured to see if the auto value of 0.42 helps. I could see how an under-extrusion could weaken the bond between the support and model layers, but at this point I can be talked into seeing the Easter bunny.

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