When you select auto mode, it grays out the box and chooses .48 (for my .4 width nozzle). Does that mean that it always just uses .48 or does it actually try to adjust the nozzle width output dynamically during the print?
If I print a thin wall feature (like a .4mm width wall) and I put the nozzle width to .4 it won't print. If I put it to .39 it will print it. If I put it to auto it won't print.. so I think it is not adjusting dynamically for the print features, but just choosing .48 uniformly.
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Alex Borro
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- Joined: Wed Jun 11, 2014 8:25 pm
Re: Question about auto mode nozzle width
I second this question.. It would be nice a really "auto adaptive" extrusion width for thin walls.
Cheers.
Alex.
Cheers.
Alex.
Re: Question about auto mode nozzle width
no thats not what the auto feature does. it automatically calculates the best extrusion diameter based on you layer height.......or atleast it always did. whenever you changed you r layer height the extrusion dia would automatically change. it appears now that something has changed im just not sure what since the width seems to stay constant atleast in the process setting.
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KeyboardWarrior
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Re: Question about auto mode nozzle width
The process and any imported 3D models are not connected, therefore it would not "scan" your model for the thinnest wall and recommend a nozzle width.dennisjm wrote:When you select auto mode, it grays out the box and chooses .48 (for my .4 width nozzle). Does that mean that it always just uses .48 or does it actually try to adjust the nozzle width output dynamically during the print?
If I print a thin wall feature (like a .4mm width wall) and I put the nozzle width to .4 it won't print. If I put it to .39 it will print it. If I put it to auto it won't print.. so I think it is not adjusting dynamically for the print features, but just choosing .48 uniformly.
Re: Question about auto mode nozzle width
This I actually figured. Someone said it did somewhere so I was just getting clarification.KeyboardWarrior wrote:The process and any imported 3D models are not connected, therefore it would not "scan" your model for the thinnest wall and recommend a nozzle width.
Re: Question about auto mode nozzle width
I'm sure there is a real term for this in the materials processing world but I'm a software guy so I'll just call it "nozzle gain." (And, I am mostly a software guy so this could be totally wrong, too! Real materials guys are welcome.) But, when extruding an elastic material under fairly high pressure I think you'll find that the actual diameter of the extrusion is slightly larger than the diameter of the nozzle. Measuring the bits extruded during the initial purge (not counting the thin gravity-driven ooze during preheating) I do come up with pretty close to 0.48 mm very consistently out of a 0.4mm nozzle.
Now, you can (and I do) lie to the slicer about the extrusion width. A change should affect the amount of material extruded per unit length and so the extrusion multiplier would also need to change. Another set of 20mm calibration boxes would probably be appropriate.
In my own setup, I find that setting an extrusion width of 0.4 results in a nice, smooth top surface, presumably because the resulting track spacing is a little tighter. YMMV.
Now, you can (and I do) lie to the slicer about the extrusion width. A change should affect the amount of material extruded per unit length and so the extrusion multiplier would also need to change. Another set of 20mm calibration boxes would probably be appropriate.
In my own setup, I find that setting an extrusion width of 0.4 results in a nice, smooth top surface, presumably because the resulting track spacing is a little tighter. YMMV.
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ashleywebster
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Re: Question about auto mode nozzle width
I suggested to Dennis in a G+ conversation that auto width must do something "intelligent". I'm sure you have found when slicing that sometimes particular infill density and extrusion width combinations leave gaps in the top fill and you end up mucking around until you find one that packs it just right. I figured (hoped) that the auto width feature saved you the trouble and sorted out the best extrusion width to achieve the desired packing density. Or at the very least, as Jimc says, some simple math on the layer height to ensure consistent flow rate. That's what the tool tip says it does.
But everyone is saying it does nothing of the sort and I agree, confirmed in the gcode. Slicing a model with two processes, one at 0.3 mm layer height, and one at 0.1 mm layer height, produces extrusions that are both 0.49 mm wide. It appears the only thing that changes the auto width is the nozzle diameter. Is it really just a set of defaults for the nozzle diameter? Is something broken?
I'm not complaining, I get great prints from S3D, but I want to know how my tools work.
Here's the original conversation: https://plus.google.com/109071112551749 ... FsamnmmE7q
But everyone is saying it does nothing of the sort and I agree, confirmed in the gcode. Slicing a model with two processes, one at 0.3 mm layer height, and one at 0.1 mm layer height, produces extrusions that are both 0.49 mm wide. It appears the only thing that changes the auto width is the nozzle diameter. Is it really just a set of defaults for the nozzle diameter? Is something broken?
I'm not complaining, I get great prints from S3D, but I want to know how my tools work.
Here's the original conversation: https://plus.google.com/109071112551749 ... FsamnmmE7q
Re: Question about auto mode nozzle width
So on that note, what does change when you change extrusion width?
So lets say I have filament coming out at .48 and I change extrusion width to .4... does that make the tool path closer together but not change anything with amount of plastic extruded?
Or suppose I change it to .6... does more plastic come out? Or is plastic extruded only affected by the filament width and extrusion multiplier?
Still curious why if I change it to .39 it will print the .4 thin wall but if it's larger it won't print that wall.
Also curious why with my HIPS material (the G+ conversation) I'm having problems with it set above .4. Maybe my problems with HIPS aren't related to this and it's just circumstantial.
So lets say I have filament coming out at .48 and I change extrusion width to .4... does that make the tool path closer together but not change anything with amount of plastic extruded?
Or suppose I change it to .6... does more plastic come out? Or is plastic extruded only affected by the filament width and extrusion multiplier?
Still curious why if I change it to .39 it will print the .4 thin wall but if it's larger it won't print that wall.
Also curious why with my HIPS material (the G+ conversation) I'm having problems with it set above .4. Maybe my problems with HIPS aren't related to this and it's just circumstantial.
Re: Question about auto mode nozzle width
That's a good question. IIRC there are some open source slicers out there and there's a long weekend coming up so maybe I'll do some code digging and edjumacate myself on this.
I'd assume that the slicer takes the extrusion width into account along with the layer height in determining how much plastic to push into the hot end, so for a width of .4 and height of .2, you're looking at a first approximation cross section of 0.080 mm^2 vice 0.096 mm^2 for the wider extrusion width. But, as you point out, that's also affected by the extrusion multiplier which should be adjusted for a proper 100% infill.
As regards the thin wall capability, it would be interesting to print a test object, with walls ranging from the ridiculous (e.g., 0.1mm) to something achievable, using a series of manually set extrusion widths. Then note which ones printed and also what the actual wall widths turn out to be.
I'd assume that the slicer takes the extrusion width into account along with the layer height in determining how much plastic to push into the hot end, so for a width of .4 and height of .2, you're looking at a first approximation cross section of 0.080 mm^2 vice 0.096 mm^2 for the wider extrusion width. But, as you point out, that's also affected by the extrusion multiplier which should be adjusted for a proper 100% infill.
As regards the thin wall capability, it would be interesting to print a test object, with walls ranging from the ridiculous (e.g., 0.1mm) to something achievable, using a series of manually set extrusion widths. Then note which ones printed and also what the actual wall widths turn out to be.
Re: Question about auto mode nozzle width
Till now, one test I've done is to print a one shell cube with no infill and measure the wall width the adjust the multiplier to get it about right. Then if the 100% filled cube looks good too I've gone with that. Makes me think there is a better way perhaps to be doing the initial setup.
