Migration to Cura issues

[mja5860 0]

Hello all,

 

I recently made many upgrades to my printer and cannot get a good print with Cura, I was previously getting beautiful prints with Slic3r inside Repetier Host and tried my best to port my old setting.

I just upgraded to a Duet3D wifi, Chimera+ hotends, and BondTech BMG extruders as well so there's many new factors. I do have steps/mm and all basic machine settings set correctly for everything though.

 

My top layers look like garbage, blobs on corners, holes, and issues with small details, etc.

I've spent about a month already trying to troubleshoot this and have only made slight improvements, can someone please help?

 

This is for a custom built printer,

 

 

 

ABS PRINT

 

stl and cura profile is attached as well

 

mja5860.curaprofile

GoProMount.stl

Edited May 28 by mja5860
clarity

[mja5860 0]

[removed]

Edited May 28 by mja5860
Removed

[gr5 1,225]

Well it's really hard to tell.

 

One issue is that the PLA doesn't seem to be cooling down enough when you get to the 3 "fins".  So slice two of these parts so that it can do a layer on one part and then go do the other part while the first part is cooling a bit.  This will make it easier to see what the other issues are.

 

Is the fan working for this part?  You want the fan blowing on the part and not the nozzle.  Is it a good breeze?  Feel the breeze with your fingers.  Many people design fan shrouds badly.  I'm thinking you might have too much back pressure for the fans to work and need to open up your shroud.  Or maybe the nozzle cools too much when the fans come on.

 

So you have zero retractions until you get to the 3 fins.  So the second issue to tackle are retraction issues.  What is the retraction amount and the retraction speed?  Try at 1/10 current speed just to see if it's a speed issue.  when building a cusom printer you need to examine all the settings (jerk, acceleration, max velocity) and find out where the steppers can't go any faster.  This includes the extruder.  Maybe when it retracts it's fine but when it tries to un-retract if fails and you get underextrusion.  Feel the filament while it does the retraction.  Does it feel like it retracted the right amount?  Look over all the retraction settings in cura.  Watch the printer print very carefully.  Use reading glasses.  Slow the printer down to see if it gets better.  Try to see what's different when it "works" and when it doesn't.

 

[mja5860 0]

17 minutes ago, gr5 said:

Well it's really hard to tell.

 

One issue is that the PLA doesn't seem to be cooling down enough when you get to the 3 "fins".  So slice two of these parts so that it can do a layer on one part and then go do the other part while the first part is cooling a bit.  This will make it easier to see what the other issues are.

 

Is the fan working for this part?  You want the fan blowing on the part and not the nozzle.  Is it a good breeze?  Feel the breeze with your fingers.  Many people design fan shrouds badly.  I'm thinking you might have too much back pressure for the fans to work and need to open up your shroud.  Or maybe the nozzle cools too much when the fans come on.

 

So you have zero retractions until you get to the 3 fins.  So the second issue to tackle are retraction issues.  What is the retraction amount and the retraction speed?  Try at 1/10 current speed just to see if it's a speed issue.  when building a cusom printer you need to examine all the settings (jerk, acceleration, max velocity) and find out where the steppers can't go any faster.  This includes the extruder.  Maybe when it retracts it's fine but when it tries to un-retract if fails and you get underextrusion.  Feel the filament while it does the retraction.  Does it feel like it retracted the right amount?  Look over all the retraction settings in cura.  Watch the printer print very carefully.  Use reading glasses.  Slow the printer down to see if it gets better.  Try to see what's different when it "works" and when it doesn't.

 

 

I should have clarified, my post has been edited for clarity. This is ABS and I usually don't print with anything else.

 

I have retraction distance set to 6mm and 30mm/sec and it definitely retracting as it should, I did check that. I had the setting honed in very well before with Slic3r but I have yet to enable jerk with Cura so I guess I can try that next. I have a pretty large bowden tube due to the size of my printer but that has never been an issue. Should be even less of an issue now with the bondtech extruders and capricorn tubing.

 

I have slowed it down and saw minor improvements but the thing that is the weirdest to me is that at 100% flow rate, it for sure underextrudes. I have to turn it up to 150% to see the results in the images above which has to mean there is an issue some where. I ALWAYS had it at 100% before with my old setup. The extruders steps/mm is correct and I fiddled with the filament diameter settings in Cura as well.

 

My Cura profile is actually attached to my first post if that helps at all

[mja5860 0]

First of all I turned on jerk and slowed down the print speed to 30 mm/sec and turned down a couple acceleration settings. The infill looks amazing now where before it was very messy.

 

Since you mentioned retractions, I did turn that down to 4mm and like 20 mm/sec and noticed my bowden tube was loose on the extruder side so fixing all of that I was able to actually finish the print and get decent results on the gopro fin mounts. I'm not too worried about that, I can fine tune that still.

 

 

Main issues at hand:

 

I have it at 150% flow in order to not underextrude.... ???

 

And secondly, the skin looks horrible and full of gaps. I've messed with the settings that deal with the skin but nothing noticeable changes.