Height range modifier - Keeping feed rate constant but increase speed
 
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jonas-3
(@jonas-3)
Active Member
Height range modifier - Keeping feed rate constant but increase speed

Hi,

I have made a model(a simple square) where the bottom half is printed with 1 mm layer height. The top half is reduced to 0.5 mm layer height. Looking at the G-code I can see that the  speed is constant when going from 1mm to 0.5mm. What changes is the feed rate which drops with half which makes sense. 

Is this the normal way of dealing with different layer height in a model?

What I would prefer was to have a constant feed rate and a variable speed. The speed would double when going from 1 mm to 0.5mm. 

Is there a reason this is not the default way to do it, and can it even be done with PrusaSlicer?

I have a huge extruder mounted on a robot and need to print large items so it is important to have the Extruder pushing out as much material as possible. 

 

Posted : 08/01/2020 2:07 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Height range modifier - Keeping feed rate constant but increase speed

Are you using Prusa printer equipment or a different set up?

Have you configured Prusa Slicer to match your printers melt rate, and maximum print speeds etc.? if the slicer doesn't know about your huge extruder, it won't be able to use the capability!

it may be that your current settings are holding back the flow performance on the 1mm layer height as well as stifling the lower layer height  travel speed performance!

 

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 08/01/2020 2:56 pm
jonas-3
(@jonas-3)
Active Member
Topic starter answered:
RE: Height range modifier - Keeping feed rate constant but increase speed

Thank your for your suggestions. It help me in the right direction - I think

I'm using a custom setup.

Okay so I tried setting every "Speed for print moves" to 0 - which means i'm using Autospeed. I then set the Max Print speed to a 3 mm/s (I know this is very low but when I run the Gcode through my robot software (robodk) the values becomes appropriate) I don't know what the Max volumetric speed is as i guess it is as off as the max print speed. I keept i at 0

With these settings the values in the Gcode for the speed is F 97.4742 for the 1 mm layer height and and F180 for the 0.5 mm layer height. Not double up but close.

Logically one would assume the speed for the 0,5mm layer to be x2. is there any setting that might effect that it is not?

 

 

Posted : 09/01/2020 12:29 pm
Sembazuru
(@sembazuru)
Prominent Member
RE: Height range modifier - Keeping feed rate constant but increase speed
Posted by: @jonas-3

Thank your for your suggestions. It help me in the right direction - I think

I'm using a custom setup.

Okay so I tried setting every "Speed for print moves" to 0 - which means i'm using Autospeed. I then set the Max Print speed to a 3 mm/s (I know this is very low but when I run the Gcode through my robot software (robodk) the values becomes appropriate) I don't know what the Max volumetric speed is as i guess it is as off as the max print speed. I keept i at 0

With these settings the values in the Gcode for the speed is F 97.4742 for the 1 mm layer height and and F180 for the 0.5 mm layer height. Not double up but close.

Logically one would assume the speed for the 0,5mm layer to be x2. is there any setting that might effect that it is not?

 

 

Your results after changing the max print speed to 3mm/s seems to track. the F180 value is in mm/min. 180mm/min = 3mm/s.

See my (limited) designs on:
Printables - https://www.printables.com/@Sembazuru
Thingiverse - https://www.thingiverse.com/Sembazuru/designs

Posted : 09/01/2020 6:03 pm
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