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Small Perimeter Speed Setting


runninfarmer

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Posted · Small Perimeter Speed Setting

I've noticed there isn't an equivalent "small perimeter" speed setting in Cura like Slicer has, unless I'm missing something. I'm printing a calibration print that is a plate with 4 cylinders and a cube on it. Cura seems to want to use the infill speed as the speed at which it will print these interior perimeters, which is too fast for them. Is there a way to change that? Here's the print I'm doing:

cura calibration

 

 

Thanks!

 

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    Posted · Small Perimeter Speed Setting

    You might not be getting any retraction at all. You can tell in the Cura layer view - blue lines are nonextruding and if there is retraction it shows a little vertical blue line at the start of the move - the head doesn't actually move up - this is just a graphical representation of "retraction". In expert settings, set "minimal extrusion before retracting" to 0. Even setting this to .01 will probably *not* give you retraction as you don't need much PLA for each of these small cylinders.

    The hadron has the feeder on the print head so you don't need much retraction. I don't have experience with this type of printer but I know someone else who was happy with 1mm of retraction on a makerbot so I am wondering if 3mm is too much and it is drawing air into the nozzle which wrecks your control of extrusion because the air heats and expands and then much later you get air coming out (underextrusion).

    Also try a different color of PLA as the tendency to string varies quite a bit.

    Edit: added "*not*"

     

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    Posted · Small Perimeter Speed Setting

    Thanks for the info. I first started with 0.5mm retraction and 20 mm/s retraction speed, but I think I had the minimal extrusion before retraction set to a small value of 0.02mm in all tests (default value I think?). I will do some more testing later with modifying this parameter.

    I know Cura gives an explanation of "minimal extrusion before retraction," but I'm still a little confused by what it actually means? By changing this value to 0, won't it make the problem worse since the extruder won't be extruding or maybe I have that backwards?

     

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    Posted · Small Perimeter Speed Setting

    If you set this value to .1 and your retraction is 4.5mm then no portion of filament will pass back and forth through the feeder more than 45 times. Is that clear? If you set this to 0 then retractions aren't limited.

    The distance here (.02mm) is in mm of filament - not mm of print. So if you have 3mm filament this is quite a bit of printing - I think around 10mm at .1mm layers - but I didn't do the math just now. Sometimes a small cylinder can be printed in less than this amount (10mm extruding travel). I'm guessing .02 is low enough that you had extrusion every time. Like I said before you can check in layer view and look for vertical blue lines that indicate retraction.

     

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    Posted · Small Perimeter Speed Setting

    The layer view is showing vertical lines, but I'm not getting the desired retraction. I've printed my cailbration object again with green PLA now and it seems I'm getting the same artifacts. It's a string attached to a blob of filament and it's every layer. I'm now wondering if it's a limitation on my PG035L motor or not. I will try some testing of the retraction with a different motor.

    IMG 0690[1]

     

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