Nozzle crossing top layer making scars

[atlemo]

I'm sure this has been discussed before, but I could not find any threads on it – so I'm sorry if this is a repeat.

Now, I'm getting lines in my top layers because the nozzle is crossing over, leaving these ugly lines/scars. Is there any way to avoid this, with a z-lift on travel or similar?

See example:

[jfkansas]

It won't make scars as bad if you are extruding the proper amount of plastic. Since that top layer is overextruded about 10-15% the nozzle drags through the high spots leaving scars. Or is there a second nozzle that might be too low? Both will do it, but having a hot nozzle go through over extrusion is much better than a cold one. At least the hot nozzle will melt its way through.

[dkightley]

Is there any way to avoid this, with a z-lift on travel or similar?

You've answered your own question....

Use Retraction vertical lift to lift the nozzle ( actually lower the bed ) before travel moves. You'll need retraction switched on of course..but I assume you'll already be using it!

[brian442]

There are also some good tips here:
https://www.simplify3d.com/support/prin ... op-surface

In particular, make sure you aren't extruding too much plastic, because that will only make things worse!

[atlemo]

Ah, thanks guys! I had forgotten to disable "Only retract when crossing open spaces".