Large print edges lifting

#1
Hello all,

We have a gMax 1.5 XT+ dual extrude printer running marlin 1.1.9 and fitted with the gCreate heated bed.

I've been trying to print models with a large base size (anything which falls outside the 8x8" centre zone).
Each time I do some or all the edges of the print start to lift which eventually fouls the part.

I've had the same problem printing in both PLA and ABS.
The heated bed has been set to the recommended temperatures set by the filament manufacturer for each material type and I have tried a number of adhesion additives like a glue stick, blue tape and hair spray.

Are there any tips anyone has to overcome edge lifting?
Photo attached for the sort of thing i'm talking about.
Any and all suggestions will be very welcome.

Cheers,
Ben
 

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gCreate_Joshua

Administrator
Staff member
#2
One thing we do in our print service department is put 1 layer thick square "feet" down on small areas that can lift. Just create a flat square in your design software and add it to the build plate in the slicing software. This will give the print a larger footprint and help with lifting. IMG_5031.JPG
 
#3
Hey Joshua,

Thanks for the advice.
Is adding the tabs a custom setting? Do you know how it's done in Cura?

I guess the tabs could be added to the CAD model itself for later removal or just add a brim to the whole print?
 
#4
As a quick update to this. I haven't been able to find a way to put the square tabs in using Cura, though setting a brim around the part in the gcode seems to have done the trick.
Incidentally, I tried this print without any sticky additive (glue stick etc) and it has taken to the bed far better.

Thanks again for the advice.
 
#7
Yes. It is less finicky about the first layer squish than BuildTak. It holds PLA well at 60C and ABS at 100C and releases both nicely at 50C. Even BuildTak sells PEI now. BuildTak PEI is very thin so, I am not sure how durable it is. You can find thicker sheets of PEI at CShyde company. 20 - 40 mil sheets have been very durable on my machines.

I know a lot of people use BuildTak and like it but I always fought with it. The parts either would not stick down, like you are seeing, or would stick so tightly that the sheet would pull up trying to remove them.

GeckoTek EZ Stik also works better than BuildTak but doesn't last as long as PEI.

To be fair, you will always fight with ABS unless you have a heated build chamber. If you can get the parts to stick tight to the bed then they will split further up on the part. ABS is a tough one because it is designed to shrink as it cools. PETG is a good alternative to ABS in a lot of cases.
 
#8
Thanks for the advice. I think i'll give it a go.
The points you've raised are spot on for the problems I'm having right now. I got the ABS to lay nicely with the brim, left the machine over night and returned this morning to this -->

Untitled-1.jpg

Clearly this is a problem in setup and environment inherent with ABS especially as our machine doesn't have any sort of heat chamber to maintain temperature.

I'll give it a go and hopefully will see better results!
 
#9
That is a common look for a large ABS print!

If you do go with PEI and then try PETG filament, consider applying a coat of glue stick to the PEI as a release agent. I have read that PETG can bond permanently to PEI. I have always used glue stick for PETG prints, just in case! It has worked well.

Good luck.