Material counter

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Shelton
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Joined: Thu Jul 12, 2018 8:34 pm

Material counter

Postby Shelton » Fri Aug 03, 2018 2:06 pm

We can declare net weight at the start. And app could measure it to unload time. You can write it on a spool sticker what you have. So material indicator shows how much is left other words.

Jetguy
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Re: Material counter

Postby Jetguy » Fri Aug 03, 2018 7:15 pm

Just the facts:
#1 the slicer uses volume and distance. Gcode print file contains distance. As such, a density of a given filament is a massive guess and results in huge error of how much weight of filament is used compared to knowing the exact length of filament use. Again, we know the exact distance used- and that's all we "know". Weight is a total guess.
#2 Spools sadly are not sold by linear filament length, they are sold by weight. AKA the guessing game in reverse to properly know the density of that filament and then guess how much linear filament is on a spool.
#3 The filament distance used has always been displayed, as well as the guessed weight used (look at your print dashboard). The weight is only as good as your guess at filament density.

Jetguy
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Location: In a van, down by the river

Re: Material counter

Postby Jetguy » Fri Aug 03, 2018 7:17 pm


Shelton
Posts: 332
Joined: Thu Jul 12, 2018 8:34 pm

Re: Material counter

Postby Shelton » Fri Aug 03, 2018 7:23 pm

Interesting. Thank you for the detailed reply.

Jetguy
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Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: Material counter

Postby Jetguy » Fri Aug 03, 2018 7:38 pm

And I was wrong about what was displayed on the dashboard.
Apparently it shows weight based again, on the guestimate based on filament density.
The gcode print file places a total filament distance used in mm at the bottom of the file.
Gcode file filament used.jpg


The print dashboard, and the print preview in Ideamaker are using the extrapolated weight value derived from taking total distance of filament used, and then multiplying that times the density. This can be a significant source of error.
Dashbord total view.jpg

Print file detail.jpg

Ideamaker Print Preview stats.jpg


Another way to know the total linear filament distance used is the online gcode preview tool. http://gcode.ws/
Gcode Web Preview.jpg

Jetguy
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Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: Material counter

Postby Jetguy » Fri Aug 03, 2018 7:53 pm

Filament density used in those calculations is located here.
Filament settings, density and diameter.jpg

I would calibrate density by first taking any large recent print you still have the source gcode file for. Weigh the actual print and compare that to the dashboard estimated weight or Ideamaker slice preview weight. Then carefully adjust the density so that the actual and estimated weights match.

Also, filament diameter is critical, that is what causes the slicer to adjust the gcode print file to have more or less linear distance of filament.
That can lead to over or under extrusion if the actual filament diameter is not the same as the slicer value given. An explanation of how filament diameter is used by the slicer to generate the gcode print file line by line extrusion lengths is here viewtopic.php?f=8&t=7476&p=29253&hilit=makerbot#p29253 Trying to also find another lengthy explanation of print tuning related to this I recently posted.

Jetguy
Posts: 2700
Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: Material counter

Postby Jetguy » Fri Aug 03, 2018 7:56 pm

Sorry, I also realized in all the screen shots, the ideamaker slicing preview is not the same source STL and thus not the same gcode being previewed if you were comparing all the places where the estimated weight was displayed.

Jetguy
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Joined: Tue Mar 22, 2016 1:40 am
Location: In a van, down by the river

Re: Material counter

Postby Jetguy » Fri Aug 03, 2018 8:03 pm

Again, please don't take my answer wrong.
As an "Improvement" you are well in right to ask for a way to enter a known spool weight, and then have the printer "subtract" from that spool until you change it, and maybe even go the step to warn the user when it doesn't have enough estimated filament. All of that can get complicated and definitely should be a feature that can be toggled on and off when not used.
And, it's only as good as the filament density and filament diameter, along with general tuning state of your printing profile both hardware and software. It doesn't take much of an error to see a variance in the actual weight of filament used VS the estimate -especially the longer and bigger the print.

My thought is, by the time to the user take the time to do this right, tune the density and other values, you've already weighed so many times manually, I'm not sure much of this helps filament and print management.
The alternative is chipped filament spools( either RF ID tag or EEPROM) and that goes down a road we do not want to consider.


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