Second nozzle prints about 10mm to left of first nozzle

Got rather worrying issue. Tried the Vertex bracelet with two nozzles. Everything was going perfectly until the turn of the second nozzle came to print. It printed about 10mm to the left of where it should have done, so that it missed the ooze shield.

Very odd I thought. Checked distance between nozzles. Everything correct there. What should I check next? Correct firmware is loaded, indeed everything seemed to be working perfectly until the second nozzle printed. Clearly a setting somewhere that isn’t right. Gone through everything I can see for two nozzles, everything looks as it should I think… :frowning:

Can you post a picture of the print?
i took one piece of the bracelet and printed that a few times and tweaked the distance untill is perfect.

Best Regards,
VEL337

No, this is much more serious than that. At first I thought we were back in the print area for two nozzles problem. I wondered if the problem was down to me choosing the left extruder instead of the right as the basis of the bracelet. So I faithfully copied the assignment of objects to extruder exactly as in the manual example.

The print this time began ok, both nozzles looked like they were printing in roughly the right areas:

But I came back 5 minutes later and something very odd was going on. Now the left extruder had jumped to the right by 5 or 6mm, so I had to abort:

So what could be causing this? Hope the printer hasn’t been damaged by the previous failure to warn about extending an object into a no “print zone”, but looks more like a software bug.

Looks like it missed a step because on the right part of the picture the yellow print is also shifted.

I’m just busy printing the bracelet to test my second nozzle. I’m at 80% and everything went well so far.

I had to adjust the second nozzle Offset X to “-24,25” mm.

But I am wondering about the mess the dualhead printing job turns out. The printed object looks good but I get constant dripping dots from the second nozzle and a second “wipe tower” from the second nozzle drops, is that supposed to?

I have to overlook the print all the time to clean up the mess. I’m printing only a small 2x1 lego brick with all the cylinders in yellow and the block in lightblue.

@zefix a picture would be helpfull
@biscuitlad first of all the first (yellow one)extruder seems to be too far away from the bed,this can lead to problems when printing (losing some steps). make sure the height is correct.
Can you post also a picture of the whole bed with the wipe tower and such

Best Regards,
VEL337

Call me lucky, everything was fine without any adjustment and my print ended without any issue.

If your nozzle is dripping, perhaps it’s too hot? Was it set for the right filament?

Is this normal that every time the print head switches it moves to the most left side on x axis of the print bed?

@biscuitlad
Sorry i don’t want to spam your thread, should I open another one?

@raby
I use the standard setup with 210°C and PLA setting for both nozzles in repetier for cura.

yes it is normal. It goes to that position to heat up the nozzle

[quote=“Zefix”]


Is this normal that every time the print head switches it moves to the most left side on x axis of the print bed?
[/quote]
Yes it’s normal.

My setup for PLA is 200° and 75% flow (else too much filament is extruded and the surface looks sticky).

OMGF! Tanks raby that’s a hell of a difference now with these settings. How could the velleman crew oversee that?

Here is the bracelet completed.

The black part is in ABS and the white letters in PLA.

As you can see it’s far from perfect. Some black is leaking in the white and the edges aren’t sharp. As usual, advise is cheap : when installing my second extruder I forgot to reduce the flow in my ABS setting ;(.

The lower layers on the build plate look brittle like not heated high enough?

The same like I experienced with the 200°C 75% settings, there needs to be a low layer mode with higher temps in cura! Or is there one already linke I saw in slic3r ?
I already turned off the fans for the lower layers in singlehead like in dualhead mode but not much changed.

No they’re no brittle. Just a bit uneven (too much filament extruded tends to spread laterally).

Which side of the bracelet in the above pic was on the build tack? I think the inner one and that looks not homogeneous to me. Like with little holes&cracks and such.

You’re right there are some irregularities. I ruined the Buildtak trying to remove a large piece sticking like hell with a long cutter blade and I scalped large chunks of the surface.

I try to print on the intact part but for the bracelet I had to use the whole surface.

[quote=“VEL337”]@biscuitlad first of all the first (yellow one)extruder seems to be too far away from the bed,this can lead to problems when printing (losing some steps). make sure the height is correct. Can you post also a picture of the whole bed with the wipe tower and such
Best Regards,
VEL337[/quote]
@Vel337
Yes, the nozzles were different lengths. So I spent the evening trying to take them apart. The original nozzle was almost impossible to take apart due to molten plastic getting into the slot next to the nozzle. Finally got both nozzles identical in length. Will post a picture later in the week once they’re back on the machine and I’ve re-calibrated the bed.

But are you sure such a small discrepancy between the nozzles could cause it to skip some steps? After this was after quite a few layers had already been printed. Can you explain what causes it?

Yes when the filament curls up, the second cold extruder can be blocked

Sorry, but how does that explain the letters shifting to the right as in my photo?

Does this shifting only appear in dualhead prints like this bracelet and onehead prints don’t shift at all?