What to try for consistent thin/missing spot in first layer of print?

Bambu Lab A1 Series Troubleshooting
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To start, I’m brand new to 3d printing – just a few weeks in. So no advice is too basic :wink: First the facts…

I’m running an A1 Combo (latest firmware) and have been using all Bambu filaments to this point (both PLA Basic and PETG translucents) with great success. Clean prints, no real issues, very pleased.

While waiting for my additional filament order to come from Bambu, I decided to pick up a roll of Elegoo PETG (normal PETG, not their Rapid or Pro) from Amazon to print some spools I’ll need. (Just picked PETG for more durability and a little more heat resistance in my dryer).

I loaded the Elegoo PETG in the AMS using the “Generic PETG” profile and printed a couple simple test items which came out fine. The Generic PETG profile seems to run at 255c.

However, when starting up my spool print I noticed a couple thin/missing areas in the first layer. So I decided to stop the print, completely clean the plate, and leave the filament in the dryer at 50C overnight.

The next morning I tried the print again and it was “better”. Only 1 smaller thin area in the first layer (instead of 2), but it was in the same location as before. After that print finished I ran another (after completely cleaning the plate) and had the same thin area in the same spot:

IMG_1072
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So I’m just curious what people might suggest to correct that area, as the rest of the print is really quite good.

I don’t think it’s a dirty plate as I clean it very well with hot water and dish soap and dry it completely. I’m drying the filament further tonight in case that helps. I let it run “Bed Leveling” and “Flow calibration” before printing.

My total noob suspicion is that it’s just not able to ramp up the flow quick enough in that area, as that’s basically where the outer band fill is “started”.

But what might help, bumping up the temperature? Some other setting or calibration?

Any suggestions welcome… Thanks!

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I think this is an issue with the sliced file. Try using arcane wall generator

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Well, I only use Bambu filament but I’m pretty sure all PETG is meant to be dried at 65C, so at 50C you might need days of drying. Then again I cannot relate this to moisture in the filament, this usually would cause extra extrusion due to the moisture / steam pushing extra filament out of the nozzle.

You could vary the infill direction angle which might give a better result.

But I’m going to go ahead and suggest something entirely different. I did the same thing, I needed spools so I went to find some, holy ■■■■ hexagons are cool… It’s great to use less filament and get a cool look but I use these for Bambu refills which can be a complete pain in the ass with tangling. So I eventually printed more solid spools, so the sides don’t easily flex outward allowing the outer edge of filament to slip into the crevice…

Not to discount your issue, it’s just an odd issue that could be complicated to solve.

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@Lenyo and @User_631303032 thanks for the suggestions and link!

Just to follow up. After drying last night (only choose 50c as that seemed to be the default for PETG in the Sunlu S2 dryer I have – sounds like that’s low) I tried a print this morning. Only other change I made (which I should have mentioned) is that I sliced and printed from Bambu Studio rather than the mobile Handy app I was using before. I didn’t change anything in Studio other than choosing .4mm A1 as the printer (since the profile seemed to be for another printer). The result was good, no missing patch in that same area. :slight_smile:

It seems like moisture probably wasn’t the issue considering it was the same location each time, and it sounds like it would have pushed extra out which I wasn’t seeing anywhere.

So that leads me to believe slicing via Studio was just “different” than Handy, which seems to do its slicing via some cloud service. Studio is still somewhat of a mystery to me (mainly the vague dialog popups about profile changes and how it seems to add profiles to my set from projects for other printers which I don’t have). But I guess it’s time to get more familiar so I have more flexibility.

Thanks again and I’ll definitely try printing that other spool, as this hex one does seem pretty flexible. I haven’t used it yet to know how bad that is though. :sweat_smile:

1 Like
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Glad you appear to have it solved.

I exclusively use studio and I had the same issue at first, it is hard to understand this ‘Save modified value(s) / Discard modified value(s)’, but in the end for me its always DISCARD.

It is saying, you made some process changes for this model, do you want to save them to a new process profile? Like the default is ‘0.20mm Standard @BBLX1C’, if you were to save the changes it would ask you to create a new process profile name to save it under. But I just keep these types of changes with the .3mf file for the model in question, I don’t need to save it for some other similar model, I will handle that manually if and when the time comes.

Also, I think the selecting of the wrong printer is just a bug that has been around for quite some time, certainly there is a software solution but they haven’t fixed it yet so you must simply select the proper printer first.

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Thanks again, good info there.

IIRC after changing the printer to A1 .4mm nozzle is when I got a dialog with 3 options: save, discard, use. Just going off early morning memory though, will have to study it next time.

I assumed it was changes to the profile based on the new printer/nozzle combo I chose (and potentially new Studio defaults?), and chose “use” which I assumed would would just “use” the changes for the model I’m working with(?).

I’m confusing myself just thinking about it. :slight_smile: Definitely have to play with it more to be comfortable.

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You’re right, I forgot about that scenario I think. You definitely want to "use’ the changes in that case where it prompts you when you are changing the selected printer.