Globular final 10mm

[furball 0]

The results with my UM2 have been really good and I am printing 100% solid ABS however my final layers end up globular and melted. This is a problem as these layers often have detail. I don't know which route to take to solve the issue , can anyone help?

My settings are Speed 20mm/s, Layer height 0.1mm, enable retraction, no fans, Min layer time 10 sec.

I hope the following pictures help.

 

 

[pm_dude 27]

Hi furball,

I had the same issue at the beginning

 

The problem is that the minimum layer time will not be respected if the printer as to slow down less than the min print speed. That value is set in the expert settings -> Cool -> Minimum speed.

That value is 10mm/s by default I think. So regardless the the min layer time you put it will not go slower than that speed. This causes the hot nozzle to melt the plastic in place.

If you enable the Cool head lift option just under the minimum speed you will notice 2 things:

- The head will lift and move away from the model whenever the min layer time cannot be respected.

- In Layer view you will see the blue toolpath showing the head lift but also the layers will be in dashed form instead of being in tick paths.

 

So you can:

- use cool head lift which will cause some small strings that are usually quite easy to remove

- print more than one version at the time

- add a tower next to your print to allow the print to cool more

- add a blob of geometry next to the object at the layer you start needing it so it cover the layer time. This is what I usually do.

 

See the box on the tip?

 

[furball 0]

Thanks for the reply pm_dude I shall try your suggestions next time I print.