Z axis artifact

Hello everyone. I have just printed this owl with white filament and I notice some kind of z axis artifact. It doesnt seem like wobble for me, more like skipped layer or something.
Would you guys mind taking a look and giving a hint what is the possible cause? Thanks.

I am printing layer height of 0.1575 mm, I have calculated it from prusacalculator, as my wanted layer height was 0.15mm. I am using TR 8x1.5 spindle for my z axis.

Edited 1 time(s). Last edit at 12/26/2014 02:33PM by Capinho.

I found when my prints suddenly get rough its because something is loose or wearing out.
I recently had to replace my print bed bearing holders because they had cracked and were causing movement and bad prints.
another time my extruder body cracked where it bolted on and caused movement in the hot end.

Its worth working your way around your printer looking for wobbly bits or play where you dont expect it.
Everything should move smoothly with no play or snags and you should know by feel if its not right or worn.

Gordon

Gordon, my belts, bearings etc are pretty tight and seem to look good.

Does anyone have any ideas how to solve these wavy walls and Z axis lines? Here is the album with some more photos

[onedrive.live.com]

Edited 1 time(s). Last edit at 12/29/2014 02:28PM by Capinho.

Hi,

I've found a similar problem after having installed a heated bed on my Prusa i3.
A similar print without the heating would have a comparatively much better quality. First I've blamed the effect of the dilation of the heated bed but the root cause was the bang-bang mode that was apparently affecting the quality of the print.
After having switched the bed to PDI heating mode, the results were much much better.
Of course, if you're not using an heated bed, the cause may lie somewhere else.
Good luck.

Same part:

Before:



After:


Edited 1 time(s). Last edit at 01/06/2015 02:56PM by mmemetea.

Quote
mmemetea
Hi,

I've found a similar problem after having installed a heated bed on my Prusa i3.
A similar print without the heating would have a comparatively much better quality. First I've blamed the effect of the dilation of the heated bed but the root cause was the bang-bang mode that was apparently affecting the quality of the print.
After having switched the bed to PDI heating mode, the results were much much better.
Of course, if you're not using an heated bed, the cause may lie somewhere else.
Good luck.

Same part:

Before:

nuf5xHL.png

After:

HVonqLi.png

Thanks for your reply.
Interesting thing, will look into it. Dont you think that it could be just plastic issue? Could you try to some kind of test with heatbed on and off with the same material?
And could you tell me more about the heating modes you are talking about? Thanks

Edited 1 time(s). Last edit at 01/06/2015 03:56PM by Capinho.

I have did some research about my heatbed, I have PID heating mode enabled. Probably will adjust PID settings, cause they were not adjusted, but they seem to be fine (no temperature jumping, it looks constant)

Could be your hotend a little loose. Or potentially how you are feeding your filament in...if it is not being fed in a consistent way you could see things like this. Also could be from your z axis lead screw.

Edited 1 time(s). Last edit at 01/09/2015 12:33PM by Jimmybuckets.

Hi again,

I don't think the brand/kind of plastic is really the issue here. I actually did some tests with the same part and the same plastic to debug this particular issue, but just didn't take any pictures of it (i'll do it if I can find the time).
I also found that getting a separate power supply exclusively for the heated bed was also a good solution (see recommendations from Tom Sandalerer here: [www.youtube.com]).

Bump. Still fighting this issue, making me crazy. Someone, anyone? Any ideas, thoughts?