Understanding flow settings

[Supramaker 0]

I have a simple question that is intriguing me for a while now and I need to solve it at last, because it is so basic for a good print.

 

Assuming following situation:

I define a new custom material and set a flow for this new material to 98% (for example). This is the optimal setting relative to what I have already determined via e-steps calibration.

Then in the materials section of the quality profile, I set the flow to 100%.

 

Now what is going to be the effective flow of my prints with this custom material selected? Will it be 98% or 100%? Will those settings substitute each other or are they supposed to be multiplied?

 

To be more clear:

If I set flow 95% in the quality profile, will be the resulting flow 0.98 x 0.95=0.931 (or 93.1%)? Or will it be just 95%?

 

I already know that the quality profile settings override the material settings if changed. In this case, I see no symbol at the left side of the corresponding field that would allow me the reset the changed value in the quality profile to the "default" value of 98 from the material settings, suggesting that both values work together (by multiplying).

 

Although the quality profile settings override the material settings, in this case of the flow value it would make sense that the quality profile setting would be just a modifier to consider flow settings specific to the particular print part than to the material.

 

And by the way, what other settings of the quality profile behave in a manner that they do not replace but modify the materials settings, if any? Thinking about "Scaling factor Shrinkage Compensation" - it depends also on which part I anneal or not after the print, and since there is no special setting for shrinkage of annealed parts...

 

Sorry to ask that simple question but I could not find an explicite answer.

 

(using Cura 5.5).

[GregValiant 1,258]

The "Flow Rate" is what is entered into the setting boxes of the material section in Cura.  It is not cumulative but rather an over-ride.  If you have the default flow of a material set to 98% and you enter 100% into the Material Settings flow boxes, the flow will be 100%.

If you right click on a setting box in the material settings you can select "Use value from Material".  You have to look closely.  If a setting has been over-ridden then the font of the setting changes to "regular".  If the setting is still linked to (in this case) the material then the font of the setting will be "italic" and the "circle arrow" should be there.

If you install AHoeben's "Material Settings" plugin from the Marketplace you can add additional settings in "Manage Material / Print Settings".

 

"...no special setting for shrinkage of annealed parts..."

So, how are you annealing the prints?  I ask because this has come up before and I've written a post-processor to do a timed cool-down of the bed and/or build volume.  It will even move the print head out of the way so you can put a cover over the print (deluxe!).  I haven't posted it so it's just sitting here.  If you think it is something you could use I'll post it.

 

 

Edited February 4 by GregValiant

[Supramaker 0]

Thanks, now I am certain how to deal with those values.

 

I already have the Material Settings plug-in installed, and just because I wish to consolidate the settings a bit I wanted to know how this works. Then I will have to probably put all types of flows in the Material profile itself and only change what is needed case by case.  For example, I found that for hinges, it helps to lower the flow 1-2% to allow for clearance (I know that there are better ways like Horizontal Expansion, ordering or outer walls, and exclusive mode).

 

It is a pity. I hoped to be able to separate strictly material dependent things from all other cases.

 

May be I will come back to you for a postprocessing script to anneal the parts in place. Actually, I am not annealing but I printed a support part for filament roles featuring a small fan, all covered, on the heated print plate, in order to dry filaments - not far from annealing (just a higher temperature is needed then).

 

Thanks a lot.

[GregValiant 1,258]

You don't need a post processor for that.  You could hand code a short gcode script and print it.

M140 S60

G4 S7200        ; "S" is in seconds so that would be a 2 hr dwell

M140 S0

 

If your mainboard has an output for a second fan you could get fancy and spend more money on another 24v fan and add a M106 S255 P1 line in there.  The bed and fan would turn on, wait for however long, and then shut off.

 

[Supramaker 0]

Yeah, exactly that is what I am working on. I am trying to find out how to independently control one fan output in my Duet2 WiFi (I've got several) and setup a macro for that, should be viable.

 

I meant the postprocessor for annealing purposes; not a bad idea, by the way. Depending on isolation of the cover and of the underside of the heatbed, a quite high temperature can be achieved (I would need something like a tart cover or a bottomless cardboard box to cover the build plate since my printer is not fully enclosed). I left a bluetooth sensor inside while drying the filament role and can easily control the temperature in real time. Last time I got rid of about 15 g of water.

 

I recently read somewhere that annealed PLA has allegedly the highest stiffness of all kinds of common filament materials.

 

A quite troublesome thing remains though: The unpredictable degree of shrinkage, which makes the piece useless as technical part. But anyway.

[GregValiant 1,258]

"...annealed PLA has allegedly the highest stiffness..." 

I would call it "brittleness".  After having been dried at around 115°F, I found that it can break when being pulled into the extruder.  It prints a little different as well.

 

I just looked at an image of a Duet board.  On a single extruder printer the layer cooling fan is normally plugged into "Fan0".  The fan command M106 has the "P" parameter for the fan number.  You can plug in one of your fans to the Fan1 output and send M106 S255 P1 and it should go on (provided the firmware is configured that way).  That is provided that the Fan1 outlet (and/or the Fan2 outlet) are PWM outputs and that a hot doesn't have to be on for the fan to work.

[Supramaker 0]

Thanks, that is easy to verify, as I can put Gcode commands directly in the console section of the Paneldue display while sitting just in front of the 3d printer.