the first few layers print good then it goes sideways.
PETG filament.
I dried the blue and yellow for 4 hours before the print.
the black has been sitting in the ams for weeks and it printed just fine.
the only setting I changed was for it to iron the top layer.
Default ironing flow propably not enough, bump it up to 20-25.
Are the filaments same brand?
4 hours is a bit low, 7-8 should do it. But this issue is propably not wet filaments doings..
The filaments are different brands but I’ve never had this problem before.
How do you change the flow in ironing. All I see is a drop down list with what ironing you want.
I’m using the bambu slicer.
I’ve seen that kind of patterning in the blue with wet PLA before. PETG is very sensitive to water and as already mentioned, 4 hours is probably too short of drying time.
Filament doesn’t just flash dry. The water has to unstick and then migrate out of the tiny cracks where it sticks, then out between the filament loops around the spool. And that whole time it’s sticking down then lifting back off over and over. It’s a process.
thanks for the info. I’ll put the filament back in the drier and go for 7 or 8 hours and give it a go.
When you pull it from the dryer, make a note of the humidity reading in the chamber. Curious what your dryer hits. PETG is a bit more challenging to dry because either it likes to hold more water or is more sensitive to water, or possibly both.
some dryers dont actively exhaust the moisture, on some dryers you need to open the lid every now and then.
anyways, PETG is not that critical to be absolutely bone dry, compared to something like polycarbonate.
Ironing is quite tricky, and it is difficult to find one setting that works well for everything. It may also be that your Flow Ratio and K-value are slightly off, and ironing is simply making the resulting defects more visible.
Each of those filaments probably needs it’s own ironing tuning profile, too. Yellow looks under and too fast, blue looks under, cant tell about black. Ironing will require your patience in configuring, see the forums for other topics and guidance. There’s a swatch-style test print that help greatly.
Very true. I rarely use ironing anyways. Things that need to look superb i print with ,2 nozzles with carefully adjusted profiles. The right K value (pressure advance) can vary within same brand/line of filaments, depending on the colour.
I bought 4 kg of ASA Aero for a project. Two of the spools required different Flow Ratio settings, so I ended up with three different Flow Ratios in total.
I noticed this because printing RC parts in ASA Aero requires very well-calibrated filament. When I print ASA Aero or PLA Aero, I do not use K-value, so there may have been differences there as well.
So, if you are unlucky, Flow Ratio can differ between batches, even with the same filament type.
There are basically two regimes that most dryers operate under. The first is when water is coming off the spool faster than it is removed or exhausted from the dryer and the humidity in the dryer spikes up above room humidity. The second comes into play after some portion of the water has already left and the water is coming off slower than it leaves the dryer.
Depending on the water content the first might be skipped but the second will always happen.
Instead of opening the lid every now and then (which does work), it’s actually more efficient to open the lid a little and leave it there. There are a number of door props on MakerWorld specifically to do this.
In my drying I prop the door slightly open and let the “fast” water just leave while monitoring the humidity in the dryer and in the room outside the dryer. After a while the water doesn’t come off so fast and the humidity in the dryer drops. When it gets within a percent or few of room humidity, I close it up.
I go even farther though. When I close up the dryer, I start a slow dry air purge. That allows humidity in the dryer to continue dropping and I pull my spools at 19% RH in the dryer at temperature. When they cool they pull my storage containers down below 10% (as low as the storage hygrometers can read). I use this procedure for all my filament and haven’t had water issues since I started doing it.
Not everyone needs to do it, but my humidity runs in the 40-50% range and I do. But propping the door open slightly (about 1/4” on a Sunlu S2+) is the first step that I always follow and it really cuts the time to get the dryer humidity down. It really helps.
This is all great information. I’m printing it now with ironing turned off.
Based on the fact the black printed great but the yellow and blue didn’t I think you folks nailed it with the different flow rates.
I still have a lot to learn.
