Diagonal Perimeter Ripples

This may not be the right place, and if so, please just say so.

I have a Thing-o-Matic, recently built from an old kit. I have replaced the extruder drive with one from Thingiverse, switched to 1.75mm filament, and generally printed a bunch of prints, some good and some really terrible.

I am currently vexed by a problem shown in the attached photo. The black item is ABS. The white is PLA. It also occurs with nylon (Taulman-618). A surface will be as if it is un-extruded, except for diagonal bands that crawl up the side.

Changing the number of perimeters doesn't mitigate it. Changing temperature and material don't seem to matter. It happened with 3mm and now with 1.75mm filament.

Does anyone else see artifacts like this? What further tests or changes might I make to reduce this?

Best regards,

-- Carl

The PLA print looks like there's over-extrusion. Try reducing the extrusion multiplier.

Regarding the bands, it kind of looks like a harmonic vibration that's creeping into the hotend. Can you randomise the layer start points to see if that changes things?

---

[3DKarma.com] - suppliers of quality, affordable 3D printer kits and filament for the UK market.

The black print looks a lot like what my printer does sometimes. I have noticed this happening when the printer stops extruding and does z lift or goes up a layer. It stops extruding or retracts depending on the settings used and begins moving and extruding again. I have noticed that this problem seems like it happens when the head begins moving and the extrusion is a bit behind the movement so the plastic comes out later than it should and it comes out in kind of blobs which reappear in the next layer and so on after that.

What helped me was speeding up my extrusion speed. This allows the extruder to quickly begin extruding again before the head begins to move again. This may not be your problem but it worked for me. I've only been printing for about five months so I'm relatively new too. Hope this helps.

JTT

I agree that it is related to layer starts... I set up a test to look for exactly that.

It is not consistent, though, and depends on something I haven't found. Moon phase? Room temperature? Atmospheric pressure?

What controls speed up the extrusion speed? I am usually slicing with slic3r, and printing through ReplicatorG, with sailfish firmware on the Thing-o-Matic.