Bad quality in TOP / LAST layers

[Joaquin Picci]

Hey, I'm having this issue.. My printer is an "ROBO 3D R1" and when i print i got some bad layers at top.
Here is an example

I was thinking it can be a slicing problem

[KeyboardWarrior]

You may want to increase your Extrusion Multiplier (Extruder Tab) slightly, and also slow down your Solid Infill Underspeed (Other tab) to get a really nice finish on the top of your prints.

[Joaquin Picci]

You may want to increase your Extrusion Multiplier (Extruder Tab) slightly, and also slow down your Solid Infill Underspeed (Other tab) to get a really nice finish on the top of your prints.

cant find the extrusion multiplier. Solid infill underspeed was at 80% and switched to 70%

[jimc]

no its not a slicing issue. the extrusions are stepping over more and more to make the arched shape of the top surface. the stepping is normal but it does look a little sloppy from being too hot. it looks like a small print and you can see the top speed is dark blue so its slowing down quite a bit but the layer doesnt have time to cool. the bed fan will help if you dont already have it on. also try printing something like this along with something else. the second object will add cooling time to the layer so the part wont get heat soaked.

[JoeJ]

It would probably help to add an extra perimeter outline, or to print at a smaller layer height in the regions that have shallow angles like that where each layer is offset from the one below it. As you decrease layer height, that offset will decrease and the prints will look better.

[Joaquin Picci]

Ok, i will try it. This happens ONLY with PLA.
When i switch to ABS i have the next problem: Top layers is ROUGH. This photo is with 1.00 extrusion multiplier. With 0.9 extrusion multiplier i can see little gaps between lines. So i have to play between 0.9 and 1.0 ?

[jimc]

You dont just set the multiplier to whatever you want. You need to print a thin wall calibration cube, and take measurements to set the multiplier. Start by setting the filament dia correctly as that works hand and hand with multiplier to calculate flow.

[Joaquin Picci]

You dont just set the multiplier to whatever you want. You need to print a thin wall calibration cube, and take measurements to set the multiplier. Start by setting the filament dia correctly as that works hand and hand with multiplier to calculate flow.

Thefilament dia is correct at 1.75mm.

[jimc]

ok just checking some people think that is just a general setting. they dont realize you need to check the filament with a micrometer and set that to the exact filament dia.

[Joaquin Picci]

Look what happened with calibration CUBE. The side is pretty nice. PLA

Z Offset 0.8
Extrusion Multiplier 1
Default printing speed 3600,0 mm/min
Temperature 210

Order of photos are BOTTOM/TOP/

The Bottom layer is now soft with an 0.7 Z OFFSET