First layer not sticking in rear corner on UM2+

[markjme 2]

I have been having a build plate adhesion problem on my 2+ despite many levelings one back corner always tends peel even with PLA. Glass thoroughly cleaned or using glue or tape does not resolve the issue and even this print a quick pit of tape was used that became part of the print. Brim did not help so tried raft which we can agree was a problem especially on such a large area.

I have rotated the glass to eliminate that as the problem.

Sure I will resolve this build plate level problem.

On the plus side printed for 17 hours.

[gr5 2,178]

I split this into a new topic.

 

This is a common problem on UM2/UM3.  The glass is tempered and the process results in glass that is thicker in the middle.  Like a hill.  Add that to the fact that we level at the 3 leveling screws so leveling is perfect in those 3 spots - this results in low spots in the 2 rear corners because we have tilted the rear of the glass down and front of the glass up (so the two front "low" corners are now perfect).

 

This results in bad adhesion because of all the tricks (raft, brim, rounded corners, glue, heat, squish), squishing the filament into the plate affects/increases adhesion the most.

 

The glass will bend back up with very little force - just a few ounces.  One solution is to bend hard the aluminum plate underneath the glass up in the corners.  This worked great for me but then I realized that the underside of the aluminum plate has the heater spread evenly everywhere and I could have damaged it!  But it's too late - problem fixed for me.  I was lucky. 🙂

 

Another trick is to put a shim - maybe a dime - under the glass in the corners.  I'm not sure what will hold down the bed in the middle though?  But it seems to work for many people.  Folded paper might work as well.  You only need to raise things about .2mm typically.

 

The best trick is to avoid those 2 corners (which you can't do with some large prints).