3d prints not sticking to bed

Make sure that the gap between the nozzle and the build plate is correct.  I use a piece of paper to calibrate all 4 corners.  Once calibrated correctly I can go for a quite a long time before doing it again.  I would use the recommended temperatures for both the, plate  60 C and PLA 200C.  I will also spray the glass plate with a thin coat of hair spray, the cheapest you can find that helps the adhesion.    After a few builds I will clean it off with a little water.  I also usually print with a brim, which also help with adhesion.  But I think the most important factor is the calibration.  There is also a lot of information on the web to help you out.

Marty

Ender 5 Pro, I use the Creality magnetic beds and I dont often have sticking problems unless 2 things:

1. Like Marty said, the nozzle is too far from the bed.

2. you have the speed turned up too high.

PLA is real easy. I would re-level and set the distance to the bed again, using the piece of paper method mentioned above. When the nozzle just buzzes the paper, it should be fine.  

Also, not all filament is created equal. Some of it just stinks.  I've found the Overture brand to be pretty consistent and reliable for printing. Available on the river site, not expensive.

If you are trying to print something that has very little area on the base, then you can turn on the "brim" in the slicer. That will add additional rings of filament to increase the area stuck onto the base and can help with adhesion. If you're trying to print a big flat object, its not apt to help that much.

You shouldnt need to crank up the temps to max to get it to work. 210-215C for the hot end, 50-55C on the bed should be plenty for PLA.

If you’re printing too fast, you’re not leaving enough time for the print to stick to itself before cooling, which will give you a brittle part that can crack and then you just print in midair (and make a mess). The default speed is usually fine (80?) but you can try turning it down to 65 or 70 if adjusting the bed doesn’t resolve it.

Some filament is prone to moisture absorption.  Is it a new roll of PLA fresh out of the bag or has it been sitting around for a while out of the original bag?

Also, is that a spring steel PEI bed or the Teflon coated one?  Teflon doesn’t stick as well. I only use it for PETG, and even then I had to rough up the Teflon a bit w a scouring pad.

Lastly, if the prints have thin walls and are tall, sometimes the corners can lift. Like Boilermaker said, adding a brim can help with that.