Switching from PLA to ABS

After some time tuning my new prusa I got results with PLA that I am pretty happy with:

From Prusa

Now I am trying to calibrate my prusa for ABS and have some issues. Here is the same part printed:

From Prusa

Which direction should I move to make this print better?

Thanks,
Slava

When I switched from PLA to ABS I had to change a few things, the main ones are:

Adjust the Filament diameter to the new ABS

Change the filament packing density to ~0.97 (or re-calibrate your e-steps / mm)

I decreased the retraction distance from 4mm (PLA) to 2mm (ABS) with an extra restart distance of 0.15

Temperature obviously

And the infill perimeter overlap I increased to 0.25 and may go to 0.3

> Adjust the Filament diameter to the new ABS
> Change the filament packing density to ~0.97 (or re-calibrate your e-steps / mm)
Yes I calibrated parameters in skeinforge so printed size matches model before printing this part and adjusted temperature.
What I don't like with my ABS print:
- Structure of extruded filament I see on printed part. Of course it is there for PLA but way not so visible. Does it have to be for ABS because of material properties?
- Top layer somewhere structured somewhere "smashed". Maybe it is not very visible on that picture but top layer on my PLA printing is much smoother and looks like one peace, not this set of lines, with some of them smashed.

> I decreased the retraction distance from 4mm (PLA) to 2mm (ABS) with an extra restart distance of 0.15
> And the infill perimeter overlap I increased to 0.25 and may go to 0.3
Thanks, I will try that

try increasing the heat by 5 or 10º. The flatness of the top layer is governed by the shape of your nozzle. It should have a flat tip with a diameter slightly greater than your extrusion width.

eg: 0.4 layer height * 1.8 extrusion width ratio = 0.72mm at least