Warts/blobs on surface

[sunnipi 0]

Hi All, using Cura 14.12.1 on a delta style printer. Printer works well overall, but I have this annoying problem. There are tiny warts on the surface all over. They are definitely not popping water content. Because, they all lineup when looked from top of the object, looks like some setting is causing the head to pause a tiny bit at these places (I observed this closely, while it is printing).

I am unable to tell from cura settings what could be causing this. I have attached a picture link below.

https://drive.google.com/file/d/0B3Nu2gfv_8foZjNncVZ0UjdKS0k/view

Would appreciate any input.

thanks

Ram

 

[mnis 11]

Hi SunniPi

Material?

Temperature?

Speed?

Any special settings?

...And how it looks with the weather? :mrgreen:

Markus

 

[Daid 306]

Does this also happen on a square tower? If not. Then it's most likely the firmware which cannot keep up with the high amount of GCode commands. For a Delta printer the firmware needs to do quite a bit more processing and this could result in micro pauses.

 

[aviphysics 9]

I have seen something very similar to that when printing a double walled cylinder. In my case, it looked like it was due to oozing during pauses in z height adjustment and when the printer switched direction in transitioning from the inner layer to the outer layer or back.

 

[rpress 1]

Yes, it looks like blobbing is due to overloading the printer motherboard. If yours shows "Buf" on the LCD display this would go down to zero when the blobbing occurs.

If the STL has lots of polygons the resulting gcode can have lots of moves. This causes problems on the less powerful motherboards like those based on mega2560. Add in the delta calculations and this is too much.

I have made a plugin that trims the gcode, reducing the unnecessary moves. In a few days I can share this if you want to try it.

[rpress 1]

Here is the Simplify plugin. This reduces the number of short moves to keep from overloading the printer motherboard and causing blobbing, etc.

https://github.com/presslab-us/Cura-Plugins/blob/master/Simplify.py