Infill Issue - Printing as pedestals/posts instead of grid

[Morandir 3]

I'm looking for some guidance on infill problems. As always a picture first helps.

Sorry for a potato photo, but I was trying to focus on the part while printing. The GRID infill is only being printed as single pedestals/posts that fail to provide much support when the part is done. I am using the smallest nozzle size (.25) I've got, and I'm going slow (30mm/s).

The UM2 is about 6 weeks old. Bed is leveled with .002" metal shims, and I've checked the belts for backlash. The long belts have probably lengthened slightly, but are still snug, and the short belts are tight. I can move the head around with one finger, but it's not 100% effortless (I can feel the motor steps,etc).

Any guidance on the source of the problem, and how to get it to print properly?

I've been doing a lot of forum reading to not just post blindly.

Am I at the resolution of the feeder? I'm thinking the new geared feeder on the UM2+ may help.

Thanks for any help you can provide.

Also, the infill wall bond had gaps.

Settings:

Material: ABS (white)

Temp: 250C

Bed Temp: 105C

Cura Settings: 15.04.4

Layer height (mm): 0.06

Shell thickness (mm): 1

Bottom/Top thickness (mm): 1.2

Initial Layer Thickness (mm): 0.2

Fill Density (%): 30

Infill Overlap (%): 20

Print Speed (mm/s): 50

Travel Speed (mm/s): 100

Bottom Layer Speed (mm/s): 30

Infill Speed (mm/s): 50

Top/Bottom Speed (mm/s): 30

Outer Shell Speed (mm/s): 30

Inner Shell Speed (mm/s): 30

Platform Adhesion: Brim

Line Amount: 25

Nozzle Size (mm): 0.25

Cooling Fan: Enabled

[owen 19]

Hi

Your infill speed is 50mm/s compare to 30mm/s for inner and outer shells.

So drop that back to 30mm/s and see how you go.

That is a very small nozzle size so if you still have any under extrusion try slowing your speed down more or increasing your nozzle temp.

Good luck

Owen

[Morandir 3]

Owen,

Thanks for the suggestion. I did change it on the fly to 50% speed, and didn't see any difference.

Perhaps that doesn't effect the predefined print speed, but only the "global" speed. I'll try a slower print at 260C (Can't go any higher on UM2).

[peggyb 171]

the problem is that to have different speeds. Try to set your speed settings for: Infill, Top, Outer and Inner to zero. Then all the sections will have the same speed as your 'print speed'.

[Morandir 3]

the problem is that to have different speeds. Try to set your speed settings for: Infill, Top, Outer and Inner to zero. Then all the sections will have the same speed as your 'print speed'.

 

Thanks for the input. Here's the update:

When printing at a 30mm/s w/0's everywhere else (except bed layer) I was seeing the same behavior.

The first inflill line went down well, but when the next layer ran the other direction, only the peaks were getting filled to the layer. It looked like the material between the gaps slumped into the open space leaving the peaks. The photo is after a few layers.

I then slowed down to 25% speed (7.5mm/s!). The proper grid line started to fill as I thought it would. See photo lower right corner. You can see where it clearly shows a solid line grid.

Increasing speed% to 30% lost the effect. At this low of speed, I'm probably better off printing 100% fill as that seem to lay down clean and quick.

Additional thoughts or is there something I'm missing?

Settings:

Date: 1/19/2016

Material: ABS (White)

Print Temp °C: 260

Bed Temp °C: 105

Cura Settings: 15.04.4

Layer height (mm): 0.06

Shell thickness (mm): 1

Bottom/Top thickness (mm): 0.9

Initial Layer Thickness (mm): 0.25

Fill Density (%): 30

Infill Overlap (%): 25

Print Speed (mm/s): 30

Travel Speed (mm/s): 50

Bottom Layer Speed (mm/s): 20

Infill Speed (mm/s): 0

Top/Bottom Speed (mm/s): 0

Outer Shell Speed (mm/s): 0

Inner Shell Speed (mm/s): 0

Platform Adhesion: Brim

Line Amount: 25

Nozzle Size (mm): 0.25

Cooling Fan: Enabled

[peggyb 171]

try another thing: set the infill to 24%

there is a change in infill behavior between 24% and 25%, were at 24% each direction is put down on every layer, so the crossings of the layers are double.

At 25% one direction is put down every layer, it looks more dense this way..

Unless there is a reason for it, I usually use 20% or so, or less. For strength I go for thicker walls first, but this depends on your model and the use of it of course...

[Morandir 3]

Thanks for the insight