Parts of print won't stick to bed first layer

[Nifty]

So, I keep having this odd problem when I do larger (in the x/y direction) prints. Basically, the print sticks perfectly to the bed on the first layer in certain areas, but not others.

I immediately thought "Oh, my bed's not level." and then re-leveld the bed.

... but it kept happening at the EXACT same spot of the print.

I shifted the location of the print on the bed, and still... didn't stick at the same place on the print.

Then, I rotated the print 180 degrees... and the exact same spot didn't stick.

The only thing I can think is that the file and/or g-code is wonky... but it looks perfectly fine in CURA.

I basically chalked it up to the file... but then I got another completely different thing / print and had the exact same issue: one very specific part of the print doesn't stick, no matter what I do, or where I put the print on the bed.

Any ideas of the cause or how to fix?

 

[The Hat]

Any ideas of the cause or how to fix?

One of the ways of fixing this problem is to first have a clean base and/or use a good 3D spray, but the sure way to get good adhesion is to raise the bed till the nozzle is hitting it, but not scraping it, then just lower the bed after the first .5 of a mm is laid down.

It sounds like you have a bow in your platform surface...

 

[Nifty]

That's the thing, I don't think it has anything to do with the bed.

The print sticks fine on all the areas of the bed, but the point in the print that fails is always the same, regardless of where on the bed it is printed.

My thought is that it's something with the file code.

 

[stratman]

My thought is that it's something with the file code.

With two different projects/files?

Have you tried printing something that you have had complete success with in the past to see if a known working file will also be currently affected?

 

[Nifty]

With two different projects/files?

I've printed both directly from CURA, each time moving the location of the print relative to the bed... and even rotating the print on the bed. The failures are always at the same place on the model... not the bed. I really thought it was just the model itself, but then it happened with another larger model too.

Have you tried printing something that you have had complete success with in the past to see if a known working file will also be currently affected?

Yes, but everything else I've printed has been relatively small (in the x/y direction).

I keep hearing others say they think it's the bed too, especially on the CR-10 which is known to have warped glass... but that doesn't (at least in my mind) explain why the failure is specific to the single place on the model and not the bed.

Also, when the printer is printing the brim-lines all around the whole model, they all come out / stick just fine... but not the print in one part inside of the brim lines.

I wonder if one of my cura settings is out-of-whack.

 

[stratman]

Could this be a mechanical defect somewhere in the moving parts of the printer rather than a code issue or a warped bed issue?

 

[The Hat]

@Nifty, You could mail me your project and I’ll have a go at it, then we’ll know...

 

[Nifty]

@Nifty, You could mail me your project and I’ll have a go at it, then we’ll know...

Thank you for the offer my friend, but I'm starting to get an idea for where there is consistency for the failures:

It seems like the lines on the first layer stick / print just fine when there is a long / straight run... even really long runs.

BUT, there are issues when small items are printed, like the rings around holes or tiny parts of prints that are just barely touching the bed.

I put all 3 items I've been having issues with on the bed and sliced them, then marked in RED the time/places where the failures (layer not sticking to the bed) happen:

 

[berttheghost]

Just a guess, but I suspect part shrinkage. Increase bed temp?

 

[The Hat]

Or turn off the nozzle fan till the filament gets to 1mm high...