PETG and renticular fill  

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steve.w4
(@steve-w4)
Eminent Member

I am printing and testing different infill patterns and came across a weird issue.
MK3. last latest firmware, PETG, calibrated extruder and Z height is fine. Using Slic3r with the default PET or Prusa Pet profile.
But as it crosses the boundaries of the perpendicular line, it leaves a gap.
I can do the same thing by printing with LA on an MK2, with higher percentages of fill, say 20%. At
Prints fine in honeycomb, but printing in renticular, if it completes , it has holes in the fill. There is no holes in the perimeters, just in the infill and just in the second lines of the infill
On the MK3, it has a problem completing like the z height is too low and it rips it up.

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Posted : 01/03/2018 10:28 pm
Brigandier
(@brigandier)
Reputable Member


I am printing and testing different infill patterns and came across a weird issue.
MK3. last latest firmware, PETG, calibrated extruder and Z height is fine. Using Slic3r with the default PET or Prusa Pet profile.
But as it crosses the boundaries of the perpendicular line, it leaves a gap.
I can do the same thing by printing with LA on an MK2, with higher percentages of fill, say 20%. At
Prints fine in honeycomb, but if it completes , it has holes in the fill. There is no fill in the perimeters, just in the infill and just in the second lines of the infill
On the MK3, it has a problem completing like the z height is too low and it rips it up.

I have this exact issue and haven't found a fix. If you watch closely, the first line going down in the grid is fine. The second line gets "cut" by the first line since it is at the same layer height, and the petg wants to ball up on the nozzle. It's then wiped off onto the next line it hits. This gives you the crumbly effect.

For PETG I have been doing rectilinear instead of grid. Testing shows it's not that much weaker, and is much more reliable in my experience.

My MK3 Parts: [Bowden] [New Shoes] [TPU Micro Springs]...
Posted : 01/03/2018 10:38 pm
steve.w4
(@steve-w4)
Eminent Member



I am printing and testing different infill patterns and came across a weird issue.
MK3. last latest firmware, PETG, calibrated extruder and Z height is fine. Using Slic3r with the default PET or Prusa Pet profile.
But as it crosses the boundaries of the perpendicular line, it leaves a gap.
I can do the same thing by printing with LA on an MK2, with higher percentages of fill, say 20%. At
Prints fine in honeycomb, but if it completes , it has holes in the fill. There is no fill in the perimeters, just in the infill and just in the second lines of the infill
On the MK3, it has a problem completing like the z height is too low and it rips it up.

I have this exact issue and haven't found a fix. If you watch closely, the first line going down in the grid is fine. The second line gets "cut" by the first line since it is at the same layer height, and the petg wants to ball up on the nozzle. It's then wiped off onto the next line it hits. This gives you the crumbly effect.

For PETG I have been doing rectilinear instead of grid. Testing shows it's not that much weaker, and is much more reliable in my experience.

So renticular works for you or grid?
I am having that problem with renticular, but if you did grid at 45 degree, it would be the same, so same issue?

...
Posted : 01/03/2018 11:01 pm
Neolker
(@neolker)
Estimable Member

Slow down the infill speed a little bit works well for me.

Posted : 02/03/2018 12:32 am
steve.w4
(@steve-w4)
Eminent Member


Slow down the infill speed a little bit works well for me.

Well, that does solve the problem.
On the MK2S, I can print at full speed, 100mm/sec in non-linear (its horrible on linear), on the MK3 it was the same at 200 then 100mm/sec and 50mm/sec fixes it. Not a real solution since it defeats the purpose of the MK3s speed

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Posted : 02/03/2018 1:09 am
dryja123
(@dryja123)
Honorable Member

I slowed infill down the 45mm/s and that resolved the issue.

Posted : 02/03/2018 1:10 am
steve.w4
(@steve-w4)
Eminent Member


I slowed infill down the 45mm/s and that resolved the issue.

It does, but will increase times for printing dramatically.

...
Posted : 02/03/2018 1:30 am
Brigandier
(@brigandier)
Reputable Member


So renticular works for you or grid?
I am having that problem with renticular, but if you did grid at 45 degree, it would be the same, so same issue?

Prusa Slic3r default is grid (which is what you're having the issue with, it looks like). I swapped from this to Rectilinear and had way better luck, the lines go in one direction per layer creating a mesh vs a solid grid. The flow of filament is never stopped like grid.

In regards to speed, even with the MK3 you won't be able to go much past 60mm/s reliably with PETG.

My MK3 Parts: [Bowden] [New Shoes] [TPU Micro Springs]...
Posted : 02/03/2018 1:32 am
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