Filament diameter/flow ratio question

[solid-print-3d 30]

This might be a silly question, but if I have a filament that is set to 2.85 diameter and 110% flow, is that the same as just adding 10% to the area of the 2.85mm circle, or 2.898mm?

Or is there more to it than that?

Reason I ask is that I have some new filament that seems to print perfect at 2.85mmx110%flow. I cannot get a consistent diameter measurement on the filament. I have several Gcodes already prepared with Tweak at Z values setup for certain layers with 102% flow to ensure nice full top layers. In order to use these codes, I need to set the flow value in the menu to 100%, which means adjusting the diameter only.

 

[nightwish 0]

No it's the other way round. If you want the printer to put 10% more material out you have to reduce the filament strength, because like that the feeder has to put through more mm to get the same volume at the hot end. If you can just reduce the size by 10% to achieve that I cannot tell.. perhaps it's not that easy. But I'd say just try..

 

[jameshs 42]

exactly - the opposite - if you want more flow you tell it the filament is smaller as cura then thinks it has to push more mm thought to achieve the volume - as the filament is bigger than cura knows it pushes through more plastic.

so to get 110 flow when the flow is on 100% then decrease the filament diameter by the area/1.10 turned into the diameter.

 

[solid-print-3d 30]

duh, yeah... that was an oversight on my part ... The main question was, is the 10% change I want factored into the area of the filament? Surely you don't just factor in a 10% change to the diameter, you would end up with a 2.57mm value!

 

[pm_dude 27]

I guess you can try it out. It depend where the flow % is used in the code.

 

[jameshs 42]

As far as I am aware it would be area .... otherwise it is like you said!

 

[Dim3nsioneer 557]

UM2: https://github.com/Ultimaker/Ultimaker2Marlin/blob/7b301c1dcbbfad96d6991b87d549296580de852e/Marlin/UltiLCD2_menu_print.cpp#L377

UMO:https://github.com/ErikZalm/Marlin/blob/058e4465313191bf769e00a347ceccb4fbd1112c/Marlin/Marlin_main.cpp#L2813

 

[solid-print-3d 30]

@ DIM OK, Thanks, I'll try to adjust the area down 10% and see if that works. Just didn't want to arbitrairly plug numbers in for 5 hour prints that I can't watch and come back to see it not quite extruded right.

@Dude What do you mean "It depend where the flow % is used in the code."

 

[pm_dude 27]

If the flow is applied directly on the diameter setting then yes the result will be the same. If the flow is applied on the volume result it wont work.

i.e. The volume in mm3 for 1mm of filament at 2.85mm diameter is 6.38mm3. (V = h * pi * r2)

so when we set the Flow to 110% and diameter setting is at 2.85.

If the flow is applied on the diameter setting then the volume is now 7.72mm3.

If the flow is applied on the volume then the volume is now 7.018mm3.

Therefore changing the diameter setting by 2.85/1.1 might not give you the same result depending on where the flow value is applied in the code.

At least this is what I think. I might be over complicating things again...

 

[Dim3nsioneer 557]

@pm_dude: Your little essay sound a bit like Jack Sparrow - I'm sorry - Captain Jack Sparrow would explain it... :lol:

But you're right. Fortunately we know that the flow setting changes the volume and not the diameter...

 

[pm_dude 27]

All this and I had missed your comment above. Haha!

 

[solid-print-3d 30]

@Dude

-------> this is your explanation

___

/ 00

\___/ this is my head

I just use Tweak at Z to adjust flow. I asked on another topic about tweak at z adjusting flow, and the general consensus was that the tweak overwrite the flow values in the settings. This why I wanted to keep the flow values in the UM2 settings set to 100%

I don't mess around with the gcode itself.

 

[pm_dude 27]

I just use Tweak at Z to adjust flow. I asked on another topic about tweak at z adjusting flow, and the general consensus was that the tweak overwrite the flow values in the settings. This why I wanted to keep the flow values in the UM2 settings set to 100%

 

Yeah I got that part right

 

[Dim3nsioneer 557]

I just use Tweak at Z to adjust flow. I asked on another topic about tweak at z adjusting flow, and the general consensus was that the tweak overwrite the flow values in the settings. This why I wanted to keep the flow values in the UM2 settings set to 100%

 

Is this (overwriting the scaling factor in the settings) a desired behavior for you? Or would you prefer that TweakAtZ would effectively change the volume amounts for each line drawn? The factor would remain untouched and would effect the print in addition to the plugin.

The reason why I ask is the fact that I'm currently working on TweakAtZ V3.3... :ph34r:

 

[solid-print-3d 30]

for example, I have a print that has 6 tiers, or "platforms" with flat spots... think "stairs"

At each of the stair treads, I have tweak at Z slow the print down 20% and extrude 102%, then I add another tweak at z for the next layer, resetting the speed to 100%, and flow to 100%. Basically every tweak I ever make has a pair of start-stop tweaks.

For me, this has worked quite well for this particular model/print combo.

I expect it to overwrite the settings I have entered into the UM2 menu for those specified layers. Works fine.

Only problem I have at times is forgetting to subtract 1 from the layer I want adjusted. If the layer shows 29, then I enter 28 in the plugin. Another problem I have is if the print ends with a 50% speed tweak. The next print will start with the 50% tweak still activated. That's caught me a few times, as I'll wake up the next morning and the print is only half way done (looks really good though )

I did the math earlier and I subtracted 10% from the area of a 2.85 mm filament. I came up with 2.71 ( if I remember correctly). I've got a 3 hour print on with the new 10% less area, and 100% flow ) opposed to 2.85mm and 110% flow, and it seems to be identical

 

[Dim3nsioneer 557]

for example, I have a print that has 6 tiers, or "platforms" with flat spots... think "stairs"

At each of the stair treads, I have tweak at Z slow the print down 20% and extrude 102%, then I add another tweak at z for the next layer, resetting the speed to 100%, and flow to 100%. Basically every tweak I ever make has a pair of start-stop tweaks.

For me, this has worked quite well for this particular model/print combo.

 

You're definitively going to like the next version...

 

I expect it to overwrite the settings I have entered into the UM2 menu for those specified layers. Works fine.

Only problem I have at times is forgetting to subtract 1 from the layer I want adjusted. If the layer shows 29, then I enter 28 in the plugin.

 

That's a problem of the current Cura GUI. IMHO, it should be changed to the numbering used in the GCODE. However, it is maybe not the best thing to change it in the old GUI but rather when changing to the PU edition.

 

Another problem I have is if the print ends with a 50% speed tweak. The next print will start with the 50% tweak still activated. That's caught me a few times, as I'll wake up the next morning and the print is only half way done (looks really good though )

 

Which version of TweakAtZ are you using? V3.2 takes care of this issue and resets the speed to 100% at the end of the print.

 

[solid-print-3d 30]

V 3.1.2 I didn't know there was a newer version available, silly me

keep up the good work, it's MUCH appreciated!