Support consistently being struck by nozzle

Bambu Lab H2D Troubleshooting
1

Hi all.

I have a brand new H2D, arrived just a couple of days ago and I am yet to have one single successful print with this model. I have tried four times printing a particular model and the nozzle always strikes the support and it detaches from the bed. I have tried tree and normal supports, both with the same issue.

The issue always occurs in the same place, just where the support interface between the support itself and the part is. It appears to me that the interface material gets over-extruded, and it is leaving a “tail” of filament, which gets hit and then this pushes the support and game over. Video here

I am using Bambu PLA, and I am using default settings. I have done a full calibration, including high-temp calibration. I have tried printing with both nozzles, with the same result.

I have been printing for years with my P1S and have never encountered this. Anyone have any suggestions?

Thanks!

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2

Disable “reduce infill retraction” and try again. This setting is known to knock over supports and cause infill scraping.

3

What Qjo suggested and you might also consider using a smaller base pattern spacing and setting the initial layer expansion to around 5mm.

4

I think your problem is that your filament needs to be dried.

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In this other image, the same issues are evident at the top. But there is also a problem lower down. That ickiness can also be caused by moisture.

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7

Thanks all for your replies.

@Qjo I will give turning off infill retraction a try and let you know the result!

@3DTech, I wasn’t actually aware you could tweak the base pattern - I’d always prefer it to use a smaller pattern actually as I feel the bridging between the supports is quite far - and I doubt a tighter pattern will make a material difference to the print time.

@RocketSled, I have dried the filament for 8 hours in the AMS 2, which is currently sitting at about 18%RH. I will dry it again though. I’ve not noticed any stringing, those trails of filament in the first photo I think are due to the nozzle extruding in the air because the support has moved. Hopefully the bottom weirdness will also go away when I’ve dried the filament again.

8

For filament of “unknown” provenance, where you can’t be certain it’s already fully dried out, IMO 8 hours isn’t enough. The humidity of the air inside the dryer (or AMS) goes down much faster than the humidity in the filament itself. You get a rapid decrease in humidity initially, and then a really long, slow decrease as the moisture diffuses out of the plastic.

Any roll I take out for printing goes in to the dryer for 24 hours before it goes in to my AMS (I don’t have an AMS2).

1 Like