Warping / Lifting from raft


I have the problem, that models with a flat surface do not stick to the raft. The raft sticks well to the printbed, but the original model is lifting at the edges after a short time.
I’m using PLA with the standard temperature of 210 Degrees. The printbed is calibrated well.
I think this is due temperature differences but I have no idea how to prevent the material from cooling down. I thin a heated printbed wont fix this, because the heat will not arrive the upper layers of the model where the lifting is happening.


Any suggestions?

How old is the PLA? I have found this problem with stuff that has stood around for a while. I think maybe it is to do with humidity and water absorption.

The shown PLA is brand new. The problem occurs with the included material as well as with newly purchased material.

My printer’s in the basement, where it’s pretty cold. Therefore, I am afraid that there might be too much temperature difference between the extruder and the print bed. On the other hand, the raft sticks quite well to the print bed.

<p>It may be worth giving the print bed a minute or so with a hairdryer when you start. Then a couple of blasts from below as it is laying down those first few layers. Adhesion between the raft and the model is deliberately light and any adverse condition is likely to do this. It’s a bit of a balancing act between coming unstuck too soon, and not coming unstuck at all.</p>