Initial values ViscoElasticity

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Googliola
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Joined: 27 Dec 2017, 17:52

Initial values ViscoElasticity

Post by Googliola »

How can one find good initial visco- and elasticity values for the major filament types?
I am aware that the optimal values change with temperature and are specific for a particular brand of filament. But having a starting point would be tremendously helpful. Googling for abs viscosity poise didn't help much...Does anyone know of a database for such material properties??

KISSlicer is my new favourite slicer (thanks to Michael Hackney who has a lot of useful resources on http://www.sublimelayers.com and youtube)
Keep up the good work Kisslicer team - and a happy New Year
hacker
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Joined: 20 Aug 2016, 18:25

Re: Initial values ViscoElasticity

Post by hacker »

1. If you run material wizard and select filament type it will prefill new material with some value, which, I think, is based on Jonathan's experience.

2. There's an "experimental" way to get the first estimation, get there by clicking arrow button next to VE.

Sorry, if you knew about both and wanted more resources, but since you didn't mention it, thought that might be helpful.
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plm
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Joined: 31 Dec 2017, 03:56
Location: Moscow Russia

Re: Initial values ViscoElasticity

Post by plm »

Just yesterday spend lot of time playing with it (actually, I was fighting stringing). So, for PLA PreloadVE after new Material Wizard is 0.75. Tuning Wizard for PreloadVE gives me 3.5 - 4, I've tried several times. Finally I've decided something is screwed up completely - as far as I understand, direct extruder should show something close to initial value. I just set 0.75 for now.
hacker
Posts: 149
Joined: 20 Aug 2016, 18:25

Re: Initial values ViscoElasticity

Post by hacker »

plm wrote:Just yesterday spend lot of time playing with it (actually, I was fighting stringing). So, for PLA PreloadVE after new Material Wizard is 0.75. Tuning Wizard for PreloadVE gives me 3.5 - 4, I've tried several times. Finally I've decided something is screwed up completely - as far as I understand, direct extruder should show something close to initial value. I just set 0.75 for now.
Interesting, as far as I understand preload is not all that important with direct extruder, but your numbers are way higher than what I've experienced with any filament… My PLAs are in the range 0.8-1 for ~50cm bowdens…
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plm
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Location: Moscow Russia

Re: Initial values ViscoElasticity

Post by plm »

First of all - I was wrong in previous message. It was not Tuning Wizard but "Experimentally determine the ViscoElasticity" one. You can run it if you press "<=Init" at Matl tab.

I've run this wizard few times, and only later found info "just set 0.75 for direct extruder". But during 120 seconds after "beep" my extruder produces about 35 mm of string. To get PreloadVE=0.75 it should produce only 5.8 mm. Theoretical and experimental data does not match for me.
Actually I guess something wrong with my printer, not with kisslicer.
hacker
Posts: 149
Joined: 20 Aug 2016, 18:25

Re: Initial values ViscoElasticity

Post by hacker »

plm wrote:First of all - I was wrong in previous message. It was not Tuning Wizard but "Experimentally determine the ViscoElasticity" one. You can run it if you press "<=Init" at Matl tab.

I've run this wizard few times, and only later found info "just set 0.75 for direct extruder". But during 120 seconds after "beep" my extruder produces about 35 mm of string. To get PreloadVE=0.75 it should produce only 5.8 mm. Theoretical and experimental data does not match for me.
Actually I guess something wrong with my printer, not with kisslicer.
That experimental thing isn't very accurate and hard to get right, because it's hard to accurately measure average diameter. I've played with it in the very beginning, but then just skipped this step and used preload tune wizard. Normally I use the range from 0 either to double or triple of the preset value for filament type.
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plm
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Joined: 31 Dec 2017, 03:56
Location: Moscow Russia

Re: Initial values ViscoElasticity

Post by plm »

Got spare parts for extruder, disassembled mine. It was cold, and I found bubble. Right in the middle of plastic, diameter about half of filament. Vertically it's located right where nozzle part touches throat, bubble about 5 mm long.
Guess temperature is too high for that plastic, but with lower temperature parts is not so strong... May be it's time to try other filament brand.

So, if your experimental PreloadVE unusually high - try to lower temperature and see if it drops.
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