Hot bed why?

[Twac1]

So I'm wondering why you would want your hot bed to run the whole print, also isn't one layer enough to stick to the bed? In my case I use build tac and it's hard to get off. How hot do I need to heat for pla when finished for easy removal. FYI this is my first printer, I got the DIY V3 and am just starting small trying to learn. Any tips are welcom

[mhackney]

So the print does not detach due to thermal stress. Yup: read and follow the posts in my signature! They will help.

[TwoTone]

PEI is the way to go for adhesion.

[Xenocrates]

Another few reasons would be thermal expansion, as the heated material is larger than cool, meaning that if you turn the bed off, your z height will change slightly during the print as it cools off, and to avoid warping and giving some amount of initial warmth to keep the part from warping as well as make sure it doesn't cool too much for the new layer to stick while it's running slow in the initial layers