Bad sticking on large prints  

RE: Bad sticking on large prints

Make a brim connected to the part.

Then the part has a bigger atachmen to the bed.

Big flat parts and small parts, need this often, or it will curl or detache to the bed.

And ofc ourse cleaning of the bed is very imprtant, see forum for advise tips.

RE: Bad sticking on large prints

Also, remember that material type being printed can affect the probability of curling. What material are you printing? (Though I do have to say that I've occasionally seen slight curling on large, flat PLA prints. Often mitigated by a thorough cleaning of the print-bed.)

RE: Bad sticking on large prints

Before trying anything too drastic, definitely rule out basic adhesion issues. Here's some copypasta...

• A dirty PEI print surface. Even if you don't think this is the cause, it's always a good idea to make sure your PEI surface is clean before trying any other fixes. Take it to the kitchen sink and give it a good dunk with Dawn (original formula, no vinegar or hand softener variants) dishwashing soap or your local equivalent (e.g. Fairy in UK). Use a clean paper towel to clean it off, and another to dry it. Avoid using any sponge or cloth that has been in contact with grease. Above all else, avoid touching the PEI print surface. Once it's good and clean, you should be able to use 91%+ isopropyl alcohol between prints, 100% acetone when that fails, and another dunk when acetone fails. Worst-case, use a 3M 7445 ScotchBrite pad or equivalent to give it a very light buff, but only infrequently.
• If you have not already done so, try using Jeff Jordan's "Life Adjust" procedure for calibrating your Live-Z setting. It is much easier to use and understand than the on-board routine. 

RE: Bad sticking on large prints

The new forum software and I are not getting along. I edited my post with some more notes and saved it, but the additions seem to have been lost...

If you still have problems -- likely with larger parts with uneven cooling -- you can add a brim as noted by @peterm26 above. Another possibility is to add slice-time "dimes" to difficult corners as modifiers, scaling as necessary for good results.

RE: Bad sticking on large prints

A assume that's PLA.  I've also had issues with lifted corners, and generally square corners are worst.  But raising the bed temperature +10c has helped maintain adhesion on parts like Topo models.  It doesn't always work, but it helps.  I've personally been a bit wary of going above 70c, but it may be worth a try.  The parts with grid infill where I used 70c on a very clean bed, generally lifted the PEI sheet from the steel backing and left a blister that slowly healed over the next few prints.  Long PLA parts really want to warp.  Other ideas to try are changing the infill pattern to something other than a rigid grid ... changing layer print times (delay between layers) ... E.g., I printed a 150x240 flat model with gyroid infill and 70c bed, and it did not warp.

ABS and PET seem to have have even worse warp issues, and why some use enclosures to keep the entire part at a minimum temp while printing.

RE: Bad sticking on large prints

Hi,

Thank you guys,

I´ll figure out your inputs.
I forgot the filament type.... ABS

Thanks,

Enrico

RE: Bad sticking on large prints

ABS is well known for warping. It needs an enclosure to work well. Prusa print farm uses environmental control for ABS and PETG.

RE: Bad sticking on large prints

Hello,

Yes thats right !

I tried the same print with PLA and the print is perfect.

RE: Bad sticking on large prints

As a test, put a plastic bag over the printer while printing ABS. Let it pre-heat for a while. The hot heat bed will make for a nice warm air inside. That should alleviate the warping. You may need to enable the cooling fan at a low speed to avoid temperature artifacts on the print. Watch the printer the whole time. A plastic bag is a cheap quick and dirty solution, but not as good as a real enclosure with temperature control. It may snag somewhere, or the printer may get too hot, so being around the printer is a needed safety precaution. If it helps you, and you need to print ABS, then consider building an enclosure. If you don't need ABS, switch to PETG instead. The mechanical properties are similar, the printability worlds better.

RE: Bad sticking on large prints

I was struggling to get things to print the full width of the print surface, they'd always peel off on the outer edges. My solution was two part. Firstly, I had to muck around with ensuring my first layer(s) were perfectly consistent and adjust the mesh bed level correction until it was. Quite remarkable how much a +-10 adjustment can make. Secondly, I had to add a brim to the print.