Volume of plastic used - per layer?

Hello all, I wonder if anyone can help me on this, I have done searches but not found anything -

I can see Skeinforge reports total mass and volume extruded for the whole object but does anyone know how to get info on the volume of extruded plastic for each object layer.

I need to know how much filament (Length of input feedstock) is being used per layer, anyone know if this is possible to get out of Skeinforge.

Obviously it's going to change and depend on filament size and layer height, but Skeinforge knows these so hopefully it's possible.

Or any other way I could get a fairly accurate approximation from the output Gcode?

Any pointers, much appreciated.

Rich.

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[richrap.blogspot.com]

Well the volume in should be the same as the volume out. But even if it isn't, you already know the scaling factor from the Volumetric Dimension module.

divide the number skeinforge gives you for the volume by your packing density number, i think.

example
85mm^3 / .85(ABS) = 100mm^2 feedstock

edit: or do you want the length? shouldn't be too much harder, you just need to find the volume for a set length of your feedstock.

V=Pi *r^2*h
if your using 3mm feedstock. each mm is 7.07 mm^3
1.5mm is ~1.77 mm^3

edit 2:
Ah, each layer. no way to calculate that easily. Why do you need that?

Edited 3 time(s). Last edit at 06/23/2011 12:58PM by Buback.

Shouldn't there be a way to use the gcode E function? since it adds for each line it extrudes you "should" be able to look at the last line of your gcode to see how much filament has been extruded in total for your part. Please correct me if I'm mistaken.

Edit: I looked at my calibration gcode and it shows E366 for just the first line so I guess I am mistaken. Oh well, I'm still learning this stuff...

Edited 1 time(s). Last edit at 06/24/2011 12:08AM by germanicus.

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Germanicus

Buback Wrote:
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> edit 2:
> Ah, each layer. no way to calculate that easily.
> Why do you need that?

If I tell you that it'll spoil my next blog post - I will post back when I have it working and hopefully have something to show for it.

I will either slice the .STL part up into layers and work out the volume for each slice (I think Netfabb can help me with that) then apply that to get filament used.

Or maybe look at the Gcode movements for each extruding move and work it out that way.

And if all that fails, I can print the object and physically measure the filament being used.

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[richrap.blogspot.com]

On Linux or Git Bash on windows, do this command (assuming your file is called file_export.gcode)

grep -E "E0$|G1 .*Z.* E" file_export.gcode | grep -B1 E0$ | grep "G1 .*Z.*E"

That will give you all of the final moves. If you add all the E values for the lines with the same Z, that will give you the filament extruded for that layer.

the first grep gets the extruder reset lines and all the extruder move lines. the second grep selects the extruder reset lines and the line before that. the third grep removes the extruder reset lines leaving you with just the last move on each extruder run.

Thanks Greg, that looks like it should be a perfect solution, I'll give it a try.

Cheers,

Rich

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[richrap.blogspot.com]

Hi Greg and everyone,

The reason I wanted to know how to calculate the volume (length) of filament used per layer was for doing things like this -

I'm calling it 'layer selective colour printing'

And a close up -

Info on my Blog here if anyone is interested in how it was done.

Rich.

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[richrap.blogspot.com]

Fantastic!

Brilliant! I wondered why you wanted that info.

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[www.hydraraptor.blogspot.com]

Very neat. I like the filament joiner.

JB

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Check out my blog: AdventuresIn3-DPrinting

Excellent idea! Now, someone just need to make an automatic filament joiner to make even finer control of multicolored prints.

You've convinced me to make a filament joiner to make it easier to refill the feed at the end of each spool. I usually switch to another roll near the end so that I don't run out in the middle of a print. With one of those, I can just join the new roll to the end of the current one.

I get a much slower transition of colour when removing one colour and inserting the next. It would seem that joining them instead of just following one by another gets a much sharper change.

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[www.hydraraptor.blogspot.com]

nophead: Is that with your no-compromise extruder? I imagine if you taper outwards as the barrel of your no-compromise extruder did, then the new plastic doesn't just push a plug through like it might with straight barelled extruder or even one that tapered inwards. Instead it would push into the middle of the melt chamber leaving residual plastic (of the previous colour) behind.

Edited 1 time(s). Last edit at 07/04/2011 03:31AM by Greg Frost.

Yes that could be a factor.

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[www.hydraraptor.blogspot.com]