Bulging Corners on Sharp Edges

Hi All,

We are running (6) X1C printers and (6) P1S printers. Most of our printers are at least 6 months old and some are over a year old. In general, all of the machines have been great. These machines have been running almost non-stop since we got them and have been great performers. We do a lot of preventive maintenance and the machines are very well cared for.

About a two month ago I noticed some “Buldging” showing up consistently on one of the P1S. It is not the oldest machine but about 8 months old. See image below:

If you look at the end corners you can see a lot of bulging around the top part (in red) and almost nothing in the bottom part (in Green).

This is super notable to me as we do a lot of pinch-fit parts and the tolerance is tight enough that if the corners bulge then the parts don’t fit into one another.

We print this same type of parts on all of our machines and until a week ago this problem only appeared on one machine.

Over the last three weeks suddenly we have three machines now printing corners that all pretty much look this way. One more P1S and now one of our X1C.

I’m running Bambu Slicer just using 0.20 Standard Profile. Nothing special.

Just slowing down the speed does not seem to have any effect. I can get them to mostly go away by changing the profile to .16mm High.

I’ve printed some squares and other test objects to see if its a file thing but I keep getting the same effect no matter what the part is now.

Searching online I’ve found multiple different post in other forums show pictures of simular things but I’ve not found a cause and effect.

These images I found in other forums but have a simular effect to what I’m getting.

Any thought or knowledge would be most appreciated.

Thanks!

Did your preventive maintenance include the XY belt tensioning procedure?

The bulging corners are often a result of incorrectly turned Pressure Advance.

Have you calibrated your filament?

I’ll run through the procedure as a double check and report back.

I’ll re-calibrate and see what we get. We do calibrate filament when we get something new but it wont hurt to redo it. I’ll report back.

The Pattern Method in Manual Flow Dynamics calibration may help fix this if your nozzles have worn.

Note that the setting is saved to the printer, not a preset in the slicer. So on the X1C screen make sure that the Dynamic Pressure Control profile is selected for the specific filament, or in the emulator select PA Profile for the specific filament - after the calibration is re-run.

But maybe it’s something else…

Thanks for the feedback. I’ll give this a try as well. I’ve been slammed past two days but my Saturday will be spent trouble shooting. Bambu just got back to me with some thought and I need to look at as well. I’ll have an update on Monday with how its going.

Let me add my worthless 5 cents to the mix…

Firmware updates often result in unwanted ‘improvements’…
Means one should ALWAYS do some test and calibration prints after these (often automatic) updates to confirm all vital things still match the needs.

Another often overlooked factor is wear on tear on the nozzle.
Not just filaments with additives in them have a sandpaper effect - ALL filaments do this.
The standard nozzles wear out faster than hardened steel and as we calibrate for new filaments we often calibrate for those slow diameter changes of the nozzle as well.
Updated print profiles or settings from ‘the cloud’ work for NEW nozzles but won’t work well with worn out nozzles.
But I don’t think wear and tear is the issue here as your fails are too consistent and too evenly o be explained by nozzle increasing their diameter.

ASSUMING you did not change profiles and such I suggest to do a full calibration of the affected machine.
If this works apply a calibration to the other affected machines.
While at it try to work out if the machines got any updates that make them different to the still working ones.
I prefer to start with a case mode print to get the extrusion factor right.
Then a few test prints to find the best extrusion temp for the print speed(s) required.
If this differs a lot from the default I confirm the wall thickness with another vase mode test.
By now I have at least 2 profiles for the filament, one for low speed and lots of details, the other for high speed prints where the machine does not have to slow down too often.
Last but not lest the k-factor calibration using the pattern.
You want the value for the best looking corner, free of gaps and free of bulging or smear.
If speed is must do a max flow rate calibration as well.

Hi, I also have this problem, I think it appeared after updating to FW version 01.07.03.00. Although I went back to .02. the problem persists here. I’ve tried manual calibration, automatic, belt tensioning… still the same result with any kind of filament.


Even a factory reset won’t help.

Happy to test it if you share the model.