I have been getting a lot of random filament spikes on my prints. I am using a 0.4 stainless steel nozzle on my P1S with PLA, I have this issue on PETG and other types of filament. Any ideas why
That looks like adhesion issue and next layer pulling it away.
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Welcome to the forum.
The symptoms are classic of improper temps. If you’re relying on Bambu Studio for proper calibration, their calibration routines are half-baked. Try out the Orca Slicer version of Bambu Studio and run a temperature tower. What you’re looking for is the optimal temps that the filament will extrude at.
Also, I’m going to wager that you did not properly dry your filament. Even if you say you dried it for multiple hours, did you weigh it? I say that not to be confrontational but if I had a dollar for every time someone swears up and down that they “I put it in the drier for xx hours…” but they never weighed it to know if it really had moisture and if that moisture is gone.
An extreme example of a temp tower using PETG, undried on the left, dried on the right. Even a temp tower would be useless with wet filament.
A second example. This was before tuning for pressure advance which is why you also see lots of stringing.
Notice in this example the kind of underextrusion at low temps? at 200C, this filament can’t melt fast enough to produce correct extrusion.
Which is at least one of the factors that may explain this:
There are likely other items that should also be investigated.
In what order should a calibration be done?
There are varying opinions on this so I will simply offer up the sequence I do them.
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Temp tower. To confess, I often skip over this if it’s a filament I think I can guess at such as one I used before. If not, one can just try the temps listed on the box. Personally, I’ve found those temps to be too low for about 60% of the time. Manufacturers simply do not test what they label.
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Flow rate. Absolutely the very first test. This I don’t waiver on.
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Max flow rate. This can be skipped if you just take the max flow rate setting and lower it by 5mmÂł/s from the defaults. But if you want optimum speed, then revisit this again.
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Pressure Advance - This shouldn’t be skipped. For a quick test, I use the PA Pattern but for a more thorough and longer test, I use the tower and for real refinement, I then print a test cube to verify the corners look good and vary the PA settings from there. This last part is pretty OCD but if you are trying to make interlocking parts at low layer height, it saves time in the long run.
Here’s an example of post tuning refinement on a simple cube primitive scaled to a rectancle in order to make quick prints with less filament. Note the impact on the corners even though I did a full calibration. You’ll have to click on the image twice and then zoom in for it to be really obvious.
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If stringing is an issue, then I might do a stringing test. But only if its an issue. Most of the time, I will turn on “Avoid Crossing” walls which is usually good enough.
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Funny you should say that about moving to Orca, I did a week ago. I feel spoilt using Bambu printers and have forgotten everything I learned with my Ender 3 pro. I am running a temp test now however I am 99 percent sure you are correct about the print temps. 1 hour to go.