Poor top surface quality

Hi all, I am using the Village Plastics ABS filament, with the settings stock and while it used to be fine, recently I have noticed that while most layers are fine, if it makes a top surface instead of moving smoothly over it, it rattles and bumps across. As a result the top surface is very rough and uneven, even on very well supported boxy shapes.

As I mentioned, what seems to be happening is that somehow it is bumping into the surface of the previous layer, and you can see and hear the print head rattle. Yet when it is laying down the perimiter layers, it moves smoothly and quietly, it seems to only do it when producing surfaces

The firmware for the Mini is at the latest standard and I am using Lulzbot Cura

Any idea?

Cheers

Les

If it’s overextruding, that can lead to >100% fill on one of the roof layers, and that extra % goes up, causing ridges that will be bumped into on the next layer. It might be doing this on the floor layers too, but since those ridges eventually get absorbed into the body, they aren’t noticed if you’re not watching, and since the first layers are done at a slower pace, the hot nozzle melts its way through those ridges instead of rattling across them.

Check your esteps, and your filament may also be “true” 3.0mm (7.06mm²) instead of 2.85mm (6.37 mm²), which is a solid 10% increase in material.

1 Like

Thanks - I’ve been on business since last week, let me check that and get back to you

Les

I checked the filament - 2.97mm diameter, so about 4% extra. I will reset the filament settings and try again

Cheers

Les

Hi again - set the flow to 95% and have definitely got an improvement in surface quality, plus I no longer get rattling so that is a great start. I will play around with the level a bit more to see if I can improve the surface finish even more

Thanks again for the help!

Les