Tried cleaning plate, different plates, (pictured is glacier, has good adhesion and 2 brand new .4 hardened steal nozzles) but still, the printer keeps knocking off the print half or 3/4 way though on most prints. Here we have Bambu white PLA. Pretty standard stuff.
In general, I can’t ever print anything vertical, horizontal usually survives ok.
Any suggestions on things I could check? Possible over extrusion causing the top of the print to be bumpy so the nozzle bumps it or something? Any hints appreciated. Will try to upload image and time-laps. Most settings are default.
As you can see in the image, the pieces have been ripped from the brim that is still on the plate. They are not just falling off the bed or something. The head is hitting the top of the print wrong for some reason.
Timelaps only shows that it failed suddenly and leaves spaghetti when a piece gets knocked off. This print I turned off the a.i. detection and let it continue to knock the rest the pieces off (I was hoping some would make it at least… )
I wonder if this happens more often on H2D mainly because of the extruder motor being a servo. I have had this theory for a long time now:
normal printers uses steppers, which skips when the resistence is too large
H2D uses servos, which… enforces extrusion until it reaches overload current
normal printer would simply give up when the back pressure is too high
H2D would go on anyway, and it’s a strong servo
H2D knocks parts off more often when the part itself is weakly attached to the plate/to other printed parts
So for a part that is unstable or have too little support on the bottom surface, it would be pushed to death more often. Because it cannot bear the extrusion pressure. I’ve seen this multiple times with realtime videos, where my part just falls off during normal printing. This is a important hint because if it’s not something that can be fixed by z-hop (nozzle is not bumping on the part during travels, nozzle is simply printing normally but it’s the part who cannot withstand that).
Found the video it records and exact first fail- @20 seconds- watch the left most eye part and you can see the combo of the head moving and the bed going up and down causing it to hit the peice and it gets pushed.
Then the next time it comes around at 1:36 it tries to add a new layer and topples it.
Any ideas anyone?
Thats definitely an issue with slicing. not a bug, just settings. your point of contact with the bed is way small. Essentially the pressure from nozzle + material are moving the center of weight out of the actual center of model, making it wobble. Around the 15 second mark you can see the piece far left, 3rd row that has a lifted side, which later colides, and thats the result.
try to add a small ring of supports (preferably tree ones) at least for the first 3-4 mm of height, around the objects, so that it “sits” in a nest" . this will provide better stability than any brim
Agreed this could be more stable with more supports. However, this is a standard print that was setup by someone else printed by many without issues on their X1 or P1 printers.
Am I supposed to conclude- I’m ok on the H2D as long as I don’t print anything too delicate? I should keep those prints for the X1.
Well, that kinda is a bummer of a conclusion.
Ok, I have it down to a single test case, which it fails consistently at, about 30 min in, from the ipcam folder - seems like right when the bed bounces up/down a little.
Over extrusion was my thoughts also- though I’m not sure how to adjust that on the H2D. But I think it was the Variable Height Feature I had on that was getting me! I Turn that off and she prints.
Turning off VLH (Variable Layer Height) fixed the issue.
Perhaps, the bed was not taking the VLH values correctly when moving down or up?
Perhaps I was trying to print too thin? If so, that’s my user error so thats most likely it.
I’ll explore that sometime in the future, now just happy to have the print succeed. Going to try the whole lot of eyeballs next to see if it still holds and print it exactly like it should have printed in the first place, with dainty little supports.
Ah, so your saying I need to modify the extrusion when adjusting the layer height- is there a way on the H2D to adjust the extrusion?
yea, its definitely not just the variable layer height, a lot of my last print just failed. Better but still bad.
So in this case, Its over extruding and I’d need to bring it down a little to hopefully not get bumps on the last layer line.
Will look into modifying extrusion.
Is this bambu filament or 3rd party? Either way, probably check the diameter of the filament, maybe it’s not 1.75mm. If it is 1.75mm then maybe it’s too wet?
Regarding to extrusion rate adjustment for VLH, unfortunately no there is currently no way to adjust the flow rate for different layer heights dynamicly. It’s using only one parameter (the overall flow rate) and scale using its internal model. Which, gets worse when the layer height gets too thin or too thick.
It’s 1.75mm, Bambu labs, PLA Matt White ordered directly from Bambu with the little auto detect label and all that fancy stuff and its humidity is at 08% currently. Fresh bambu labs H2D .4 nozzle, left extruder.
Pretty standard stuff, that’s kinda why I started down this path of really trying to tell what is going on with this test print. Its not like this is ‘sparkle princes rainbow’ filament or anything.
So as a test, if I clone the bamboo profile, and lower the overall flow rate I might be able to get a print that does not bust. I need to read up on flowrates and profiles more I guess
Bambu doesn’t keep their filaments dry well before unpacking, so if it’s not dried by you, it’s likely to be, wet :(. Had multiple packs that I depended on luck, failed utterly by bad luck, oof.
TBH Bambu has pretty bad quality for some of their filaments
I have this exact same problem, seem like mine is doing this only with the right nossels
Ive tensioned belts, calibrated HT, swapped nossels.
The RHS I have connected to my HT AMS.
I might try swapping them over and see if there is any change.
I’m having the same problem with the H2D and clear PETG, it kept happening while I wasn’t here but now I’m hear I can hear it colliding… doesn’t seem to have a rhyme or reason… right nozzle, It’s happening just at the end of the travels so I’m going to bump the zhop a smidge
