3D Printing surface issues

[cgstudio 0]

Hello community,

I am printing these 9 inch models and I have some issues with the surface of the print. I would love to know what you think might be the way to fix such issues with the surface of the print.

I attached pictures of the issue at hand.

also the settings I used:

let me know or if you can direct me to the right path to fix such issues I would be really grateful.

Thank you community.

Ahmad

Edited September 10, 2017 by Guest

[Nicolinux 288]

Hi,

which printer are you using?

[cgstudio 0]

Hi,

which printer are you using?

Ultimaker 3 extended Nozzle 0.8 PLA white Colorfabb.

[Nicolinux 288]

Did you try to print with the 0.8 print core and the default "fast" profile in Cura 2.7? Not sure how to debug the issue now, but I see that you customised a few print settings. If you get reliable results with the default profile, then start from there and do incremental changes on small test prints.

Just out of the blue I'd guess that the wall thickness of 0.9 is off and the printer has a hard time to extrude the right amount of filament. Since the gaps happen mostly on corners, it might be another clue because the print-head slows down and speeds up there further adding further load on the extrusion system.

As for the bumps on flat surfaces, this could be due to the increased print temperature.

[cgstudio 0]

Did you try to print with the 0.8 print core and the default "fast" profile in Cura 2.7? Not sure how to debug the issue now, but I see that you customised a few print settings. If you get reliable results with the default profile, then start from there and do incremental changes on small test prints.

Just out of the blue I'd guess that the wall thickness of 0.9 is off and the printer has a hard time to extrude the right amount of filament. Since the gaps happen mostly on corners, it might be another clue because the print-head slows down and speeds up there further adding further load on the extrusion system.

As for the bumps on flat surfaces, this could be due to the increased print temperature.

Hello Nicolinux,

Yes, you are correct. The gap only happens when the printer starts a new layer in that corner. As for the wall thickness, I understand that as long as it's bigger than 0.8 which is the nozzle size, it should print fine. But that's not the case here.

Could it be the retraction settings? I left them at default. I would like to maintain the wall thickness setting but I am not sure what other issues could help fix such error and why would the core extrude less filament at the beginning of the each layer? One more thing for the print head temperature Its set according to Colorfabb recommendation. Could the print head be faulty?

Many thanks for your informative response. I will try to print using the quick settings and modify from that point. If you have any other thoughts or idea's of what the problem might be, please let me know.

Best,

Ahmad

[gr5 2,167]

@cgstudio - problems, problems.

Well the infill being at .67 is probably a big part of the problem. Pressure equalizes for this slow printing volume and then it suddenly has to speed up on a single pass wall with .8mm extrusion.

The tiny holes are caused because of underextrusion. So I would fix these with 3 changes:

1) Set infill width same as line width

2) Either set line width to .9mm (if you are doing it in one pass then it should be over extruded a bit)

3) Or even better set line width to 0.8 and inner shell to the same and do two passes (2 instead of 1). This will slow your print down a lot - two passes will be almost twice as slow so option 2 might be preferred at a small cost in qualitiy.

As well I don't see any retraction settings. Cura 2.7 has a bug where it does a retraction on layer change. Uncheck that.

Now for the bumps. Just slow it down. I would experiment while it's printing - try a speed multiplier from the UM3 TUNE menu of 75% and 50% and values in between if you want to learn more to see what speed causes those bumps. 30mm/sec speed should be pretty safe as long as *all* printing speeds are at 30mm/sec (don't want to print infill faster and then over extrude when starting the shell).