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Marlin Gaps in print

Posted: Fri Sep 14, 2018 2:33 am
by nuggs
Hi, i am totally new to 3D Printing but still i usually try and trouble shoot issues myself. After researching so many Ytube videos with no success, i have decided to seek additional problem specific help.
Just upgraded my Stock A8 to a Ramps 1.4 running Marlin, as my original A8 board died. My PLA test cube prints are coming out with gaps in the walls.
I cant work out what i am doing wrong or what i am missing.
No auto levelling, but are sure my be is level.
Using Repetier-Host with Cura Thanks for any help given.. :)

Marlin settings are:-

#define DEFAULT_NOMINAL_FILAMENT_DIA 1.75

#define DEFAULT_AXIS_STEPS_PER_UNIT { 100, 100, 400, 102}

#define DEFAULT_MAX_FEEDRATE { 200, 200, 2, 20 }

#define DEFAULT_MAX_ACCELERATION { 2800, 2800, 100, 9500 }

#define DEFAULT_ACCELERATION 650
#define DEFAULT_RETRACT_ACCELERATION 1000
#define DEFAULT_TRAVEL_ACCELERATION 1000

#define DEFAULT_XJERK 10.0
#define DEFAULT_YJERK 10.0
#define DEFAULT_ZJERK 0.3
#define DEFAULT_EJERK 2.0

Re: Marlin Gaps in print

Posted: Fri Sep 14, 2018 12:23 pm
by Moorviper
it looks like you have set the wrong steps measure your leadscrew (pitch) and use the prusacalculator ...

Re: Marlin Gaps in print

Posted: Fri Sep 14, 2018 7:12 pm
by Stefan
MV,

He should probably measure the dimensions of his print and compare them to the expected size. He could also have an extrusion rate issue if the dimensions are correct.

-Stefan

Re: Marlin Gaps in print

Posted: Fri Sep 14, 2018 7:38 pm
by oakdesign
Have you checked that the Filament diameter in cura is set to 1.75 mm.
The Firmware value for
#define DEFAULT_NOMINAL_FILAMENT_DIA 1.75 is only used if you have set your extrusion to volumetric extrusion otherwise the slicers calculates the Extrusion. And your Image much looks like as slicer is set to 3 mm Filament

Regard Richard

Re: Marlin Gaps in print

Posted: Sun Sep 16, 2018 2:46 pm
by nuggs
Thanks for your replies.
I had already checked the diameter was correct at 1.75mm but double checked it again to make sure.
I then checked the extrusion rate as Stefan suggested, and it was way off. Cleaned my nozzle, then re-tested the extrusion rate, and now it is only out by 1mm, with a huge improvement. Can't believe i missed checking that ;) .
My only other issue with it now is the top layer is a bit rough. Is there a setting in marlin somewhere for the top/bottom layers? or is that just set somewhere in the slicer?


Thanks again for the help.

Re: Marlin Gaps in print

Posted: Sun Sep 16, 2018 7:15 pm
by Stefan
Hi nuugs,

You will definitely find the top/bottom layer adjustments in your slicer. The number of layers is one factor, but you may also consider increasing the temp a little or slight over-extrusion if you want the top to appear more fused. This is going to be a fine-tuning thing specific to your set-up and may take a few tries to get it the way you want. Glad to hear you got the gaps fixed!

-Stefan