[nkvoll]

It certainly raises some good questions, and the Printrbot is a great machine at the price point (I have a Printrbot Simple RepRap clone myself). His looks pretty well calibrated as I've seen a lot of Z-wobbling artefacts on the prints from several Printrbot (Simple Makers, not necessarily the metal one).

Worth nothing is that things like the Z-scar being on the side of the cup instead of under the handle is something that's decided by the slicer (the software that translates the 3d model into printer commands).

Different open source slicers that are regularly used produce different locations for these scars -- and I'm not sure if it's actually possible to position/hint this Z-scar manually in any of them. They often do try to be "smart" about it, but the end result may vary.

[shanselman]

Do you think I just got lucky with the Z-scar and Cura?

[nkvoll]

So I just took the coffee cup STL and loaded into the latest Cura myself, rotated in 90 degrees so it was standing upright. Without changing anything else, I ended up getting the layer changes on a few difference places over the print (I'm seeing this just by analyzing the G-Code using http://gcode.ws), depending on the layer height. It starts to the right of the handle and after a while seems to sort-of stabilize almost on the opposite side of the handle and on the right side of the actual handle, before the handle separates from the cup body.

All in all, it will likely have come out decent, but certainly not under the handle as you have. This I guess is because Cura will start the new layer close to where it finishes it's previous layer by default. In other words: it depends on infill percent/pattern and model location on the build platform.

I figure this is because you've added support. This causes the print head to get a "closest" start of the new layer exactly under the handle (because that's where the support material are). So going as far as calling it "lucky", no. The support placement actually helps Cura put the Z-scars in a good place on this model. On another model, it might be the exact opposite.

(PS: I use Cura for all my slicing and I like it a lot -- but I don't feel like the software actually gives me much control about the Z-scar placement)

[shanselman]

Fascinating. Thanks for this. I was thinking it was either the support or running it through NetFabb first.

[Vendan]

you might try Slic3r, I did some tuning with the retract on layer change settings and managed to eliminate the z-scar stuff on my prints

[chokolad]

> Printrbot (Simple Makers, not necessarily the metal one).

I've heard from the couple of owners that Metal ones are much better than Simple Makers. here is the quote "but Printrbot Simple Metal is very reliable, I had one I’ve been carrying around in my car unpacked (I just dump it behind the seat, same with the tablet) and I just put it on the desk and it prints. Every time. Auto-bed leveling does wonders."

And another one from the same guy

"Just to be clear, I’m talking about Printrbot Simple Metal (not the previous wood version – that one is realty bad: it de-calibrates from day to day simply because of humidity "