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TraylorHead
(@traylorhead)
Active Member
Print defect on corners

I have just started seeing an odd print defect on some corners or shark turns.  I printed the 40mm cube to test the machine.

There seems to be a pattern to the defect

Note: I did the hardware and SW upgrade on my machine and printed several objects including the 40mm cube and all were fine.  

I have checked the X & Y belts, they are tight, all rails are lubed and everything moves freely.

I have tried adjusting the following settings in Slicer:
External perimeter first
Jerk Limits for X & Y
Quality and Speed settings.

 

Attachment removed
Posted : 23/07/2019 1:02 pm
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(@)
Illustrious Member
RE: Print defect on corners

You might check what K-factor is being used.  Though that generally affects all layers and both axis.

Also, a Bondtech gear with crude in some of the teeth may also show odd effects like this. Though the uniformity is odd.

It might help by zipping then posting your 3mf from the slice.

This post was modified 5 years ago 3 times by --
Posted : 23/07/2019 8:17 pm
bobstro
(@bobstro)
Illustrious Member
RE: Print defect on corners
Posted by: Tim

You might check what K-factor is being used.  Though that generally affects all layers and both axis.

Also, a Bondtech gear with crude in some of the teeth may also show odd effects like this. Though the uniformity is odd.

I think it's the z-seam "nearest" location that's causing the alternation. Agreed that Linear Advance (K) is worth looking into, as well as good old-fashioned slowing down. Suggest OP try a different z-seam location to confirm it moves (e.g. use "rear" or "aligned").

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 23/07/2019 8:40 pm
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(@)
Illustrious Member
RE: Print defect on corners

It is odd that on a column the slice would move to an alternate corner for each later rather than the "nearest" ... which would be the same corner, see attached.   

 

But every fifth layer returns to the same corner points to an odd divisor of 4...  unless infill is playing a role. So playing with infill types, here is what rectilinear looks like: we have a winner!

 

Posted : 23/07/2019 10:41 pm
TraylorHead
(@traylorhead)
Active Member
Topic starter answered:
RE: Print defect on corners

Thanks,  I will be checking some of these suggested settings.

The Nearest seaming is what is set right now, that kind of make since since it bounces to other corners probable causes by the infill settings.

I will post what I find after testing. I currently have a print on the machine, so will be tomorrow before i can check.

 

Posted : 24/07/2019 12:27 am
TraylorHead
(@traylorhead)
Active Member
Topic starter answered:
RE: Print defect on corners

I looked closer at the sliced preview and can see it more now, I must have been missing it somehow.

I moved to a random settings at oddly enough it puts the seams in the  middle of the side, not on the corners.

Posted : 24/07/2019 12:35 am
TraylorHead
(@traylorhead)
Active Member
Topic starter answered:
RE: Print defect on corners

If I'm right about the K factor, it's a kinetic energy of the head when in motion. The K factor is an adjust for maybe a delay when the head is changing direction.

If so, just like the Jerk values it causes the machine to slow down a bit to allow it's recovery of the motion?

I tried to find some information on it, but getting a lot of other stuff.

I understand the setting and why, just trying to wrap my head around it more and how to adjust to get the best quality.

Thanks again

Posted : 24/07/2019 1:02 am
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(@)
Illustrious Member
RE: Print defect on corners

There are good write ups on what K-factor is.  My  brain dead view is it adjusts extrusion based on X-Y acceleration. Compensates for the hydraulic effect of starting and stopping a viscous flow. No adjustments to any X-Y motion takes place; just E steps are affected.

Search Google ...

https://mattshub.com/2017/10/02/linear-advance/

This post was modified 5 years ago 2 times by --
Posted : 24/07/2019 2:46 pm
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