Dual Extruder test ignores Z height

On trying to calibrate the dual extruder, I’m having issues with the calibration. Basically, it ignores the Z height. I already have big issues with a non-flat / wavy bed (see this topic which I’ve highjacked - Dual Extruder First Layer Issue - #5 by Doogs75, and the photo below which shows the first layer of a raft, where the raft is printing (and barely adhering) at the bottom, but engraving the bed at the top), but on top of that, the alignment test is ignoring the Z height and engraving the bed.

You can see in the above, that the calibration lines are woeful - it’s just squidging plastic all over the place and embedding the head in the base. This is after setting the Z height to 1mm above the bed (setting it correctly, then raising one mm for both heads - I then lowered it again before doing the test print as this does the correct height). If I don’t alter the Z height, the calibration lines are printed at the exact same height, also trying to bury into the bed. This is with 0.4mm nozzles. If I change to the 0.2mm nozzles (because I actually want to do a 0.2mm print), then it cannot even force plastic out onto the bed… it just makes the marks.

Before anyone suggests Z height or bed calibration for either issue. I’ve done them both - it didn’t help.

The non-flat issue also seems to generate blockages (so far not as bad as, but similar to Dual extruder stops to extrude ). You can see this in the missing gap of the raft above. So far, I’ve been able to force these out, but only by manually releasing the drive wheel and pushing the plastic through myself. It’s led to most of my dual-extruder prints failing. :frowning: Funnily enough, it doesn’t seem to block the single-extruder, so something in the new design is not as robust.

If you have issues with a warped bed, you can try heating it up and let it sit for 20-30 minutes. Then do the calibration with the heating still on and with as many probing points as possible…

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Yep - tried that one. No good, still warped (I did have an 11x11 suggested to me by @Wyphorn, which I haven’t tried yet.

If that doesn’t fix (ie. work around) the issue, I’m starting to think I may have to run a fly cutter over the bed from the CNC to smooth the top. It’s going to screw my adhesion, but at least it’d be level-ish. (wonders if you can get just a surface to replace the old?)

What happens if you print this calibration plate:
calibration plate by titanic - Thingiverse (scale it to your bed size and 1layer height in your slicer)

Print it with 0.4mm nozzle and a 0.2mm 1st layer height to make it easier to compare.

Whats about the snapmaker dual extruder fixes? - Any done so far?


Front door:

Maybe share your grid by posting your M503?

At my point of few you are too near to the bed, even at the printed parts but its not clear on your pics.

Please respect me, i am a user like you, no snapmaker staff and simply want to help.

At a later point, not yet suggested, here is all about 11x11 grid:

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Replying for checking later when I receive mine… I was hoping this fraking thing would solve some problems for me, but seems that only will trade old problems for new ones-_-…

Dont worry there are many people which are happy user of this machine, me too.

The community could help you out if you need some assistance.

Over all it works pretty well but 3d printing is diy, this fact means you have to learn how to use the machine.

I’ve had to go back to the single-head to get the job I’m doing done (it is reliably printing prints that the dual head is not - even when using only the left head - maybe some twist or sag in the X drive from the extra weight?).

I’ve done the 11x11 level, but was confused by whether the machine would remember that specific calibration when it then goes back and does a 5x5 to be able to do the final z height paper test (or did I miss something in the instructions - that seems to be the only way to do the final test/set?).

Anyway… it seems a bit better and I’m doing parts which aren’t dimensionally critical, so I’m going to get them done.

I will try the calibration sheet, etc., at a later date when time allows (will probably be late August or Sept. before I can get back to random testing).

Also, I found my blockages were caused by the nozzle gouging the bed (it’s very warped) and this being pushed up into the nozzle.

I saw something about SM providing replacement beds if we did have bed-gouging issues with the dual extruder, but I can’t seem to find it again… Anyone know if this is still a thing?

You can order a new surface on snapmaker support. Or you can pre Order the Quick Swap Kit since there is also a new frame. You can use the “warped one” for laser / CNC.
And yes, for sure warped beds should not delivered in a 1500€ machine. When mine would be really bad (but it isn’t, i can print pretty well all over the bed), then I would run a measurement for surface like here: On achieving a perfect level

And when it is really out of specs, then support should arrange some new frame for free.

But now i am really out in this topic :v:

In my case it suddenly starts the Auto Z calibration OUTSIDE the bed area. So it never touches the bed with the left extruder.

Looks Like you used the centered holes for mounting. But you should used the other ones (See manual).