Flow wizard

Flow wizard

Postby woody3dp » 17 Sep 2017, 08:37

I've just understood that the flow tuning wizard helps determine the range Min and Max in Matl->flow adjust->Min/Max

But I have other questions:
- how do you determine the value into Flow tweak ?
- Is this value compensate overextrusion and underextrusion ? if not, where can you set a value to compensate overextrusion or underextrusion (I need to improve my top layers) ?
Thank you
Last edited by woody3dp on 17 Sep 2017, 12:06, edited 2 times in total.
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Re: Flow wizard

Postby lonesock » 18 Sep 2017, 09:37

The way I do flow tweak is to set it to 1.0, then print the rounded cube in vase mode, 1.5 loops (which does 1.5 loops on the base, then drops to only 1 loop for the vase walls). I then measure the wall thickness with calipers, and adjust the flow tweak so that:

flow_tweak = extrusion_width / actual_wall_thickness.

That's usually all I need.

thanks,
Jonathan
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Re: Flow wizard

Postby woody3dp » 18 Sep 2017, 11:14

Ok thank you, that's very simple explained like this. Does this tip also solve problems on top layers that look skinny or fatty (underextruded or overextruded ?)
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Re: Flow wizard

Postby lonesock » 18 Sep 2017, 11:50

It gets very close. Sometimes I will tweak a tiny bit more based on the top layer observation. Usually if I want a perfect top surface, I tune for the harder case and try to get a perfect solid cube. With a sparse infill print, any extra plastic has somewhere to go. But with a solid print, the extra plastic is cumulative, and you'll know pretty quickly if you are pushing too much or too little plastic.

thanks,
Jonathan
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Re: Flow wizard

Postby woody3dp » 18 Sep 2017, 12:53

Ok thank you jonathan for your light, I understand now and will try your way.
I've got an idea and you will tell me if it's worthwhile, that would use the tuning wizard.
I would like to "create" a tuning wizard which would help me fine tuning my top layers by observing each top layer at different flow tweak value relative to Z height. I've got the idea and the object, but I don't know how to "program" the wizard.
Here's the object:
IMG_3627.JPG

Each "cube" (not a cube but let's say a cube for more ease of use) has got 3 more layers (of 0.2mm) than the previous one. The height increases by 0.6mm between each cube. The height of the first cube is 0.6mm, the second one is 1.2mm...and so on. This way, I was thinking that by counting each cube from the beginning, I could find the height of the best looking top layer and enter this value into the flow wizard tuning (don't need a ruler), which in return would give me the value to enter in the flow adjust (flow tweak).
For example, if the 8th cube has got the best looking top layer, I do 8x0.6=4.8, I know the best top layer is at 4.8mm from the base, so I would use this value in the "Best Z [mm]"

I think it can be useful to get a perfect top layer with only one test print. But I don't know how to create my own tuning wizard (I guess I have to use <tuningval> and "Every N layers" but I really don't know how to do that.) If you, jonathan, or someone else could help me to create this, I would be very thankful.
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Re: Flow wizard

Postby lonesock » 18 Sep 2017, 13:51

That's a very cool idea. I would probably try it by setting the steps per mm for your extruder. You will need to know the proper number of steps per mm for your extruder to start with.

For example, if your correct steps per mm is 800, you could test a flow tweak from 1 (800 steps/mm) to 1.1 (880 steps/mm) by setting the <TUNINGVAL> from 800 to 880, then in every N layers (with N set to 1) use the G-code:

"M92 T0 E<TUNINGVAL>"

You will probably need to tweak things a little to match your machine. And don't forget to set the correct value again in the Postfix! (G-code is a state machine, and we just messed with the state!)

thanks,
Jonathan
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Re: Flow wizard

Postby woody3dp » 19 Sep 2017, 11:26

Thank you Jonathan. I understand the idea.
I've got a prusa I3 MK2, the step per mm of my extruder is 161.3
I want to start the flow tweak test from 0.9 (161.3x0.9=145.17) to 1.1 (161.3x1.1=177.43)
Until here I understand.

-But I don't know how I set the <TUNINGVAL> from 145.17 to 177.43.
-I don't even know how I can use the G-code in every N layers (with N set to 1): "M92 T0 E <TUNINGVAL>" (where in kisslicer should I type all of that?)

Sorry I'm a noob concerning G-code...perhaps I should wait for the kisslicer 1.6 manual to understand all of this.

Anyway, thank you for your time.
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Re: Flow wizard

Postby pjr » 19 Sep 2017, 11:35

The way I understand things, in the wizard, you select <TUNINGVAL> in the "Parameter to tune" and then set the start (0) to 145 and the end (top) to 178 (rounded).

Then in Settings/Printer G-code/N[*} Layers, you enter the M92 G-code suggested by Jonathan, and ensure that [*] N Layers on the left is set to 1.

Peter
Please note: I do not have any affiliation with KISSlicer. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss.
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Re: Flow wizard

Postby hacker » 19 Sep 2017, 13:09

pjr wrote:The way I understand things, in the wizard, you select <TUNINGVAL> in the "Parameter to tune" and then set the start (0) to 145 and the end (top) to 178 (rounded).

Then in Settings/Printer G-code/N[*} Layers, you enter the M92 G-code suggested by Jonathan, and ensure that [*] N Layers on the left is set to 1.

Peter


Yes, that's how I understand that too, I haven't tried to tune flow, but I was trying to tune RepRapFirmware's preload and retraction settings this way (can't say it was a tremendous success, but generated tuning gcode was what I expected it to be ;)).
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Re: Flow wizard

Postby woody3dp » 19 Sep 2017, 23:08

Ok thank you Peter (and Hacker for your comment), I understand now. Sorry, I feel stupid, but I need those kind of details sometimes to understand... :oops:

Concerning the postfix, what should I write once I find the correct value ? something like "M92 E<newsteps>" ?
Can I write at the beginning of the G-code, the end, or it doesn't matter ?
Here's my post fix for the moment:

G1 Z<Z+1.0> E-<DESTRING> F7200 ; Lift and retract
G1 X0 Y200 F3600 ; move bed for easy removal
G4 S1 ; pause 1 second
M107 ; turn off fan
M104 S0 ; turn off temperature
M140 S0 ; turn off heatbed
M84 ; disable motors

Thank you
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