Intro and looking for advice on printer selection

[curious aardvark]

well before you get a cr-10 have a look at the qidi: https://www.amazon.com/TECHNOLOGY-3D...idi+3d+printer

Basically a flashforge pro, just cheaper - and given the millions of hours these printers have printed abs all over the world - it's not an issue.
Well 3d printed abs has a lot of issues and I wouldn't personally bother with it - but mechanically there's no problem.

That said trakyan is right - dual extruders sound cool - but in reality they are a real pita.
What you actually want is either a machine with independant dual extruders - like the bnc3d sigma, OR a machine with two feeds into one printing nozzle. Which you could probably add to a cr-10 fairly easily.

[Don McLean]

like the bnc3d sigma.

That's very interesting. I'm guessing it uses two independent limit switches for homing on the gantry axis, to home each extruder, one to each side? Plus it has a proprietary calibration sequence built into the machine to get it to work right. I wonder if you could do this on a DIY machine?

Looks like they used very nice linear components for the X and Y but for some reason used unsupported 10mm linear rods for the Z axis.

So is the common problem with dual extruders one extruder leaking on the print or misalignment with one nozzle higher or lower than the other?