Here’s an example:
This is PETG.
While removing parts I get pieces of the bed on them. This is not normal, right?
What can I do to prevent this from happening?
You can add a layer of glue, this will act as a barrier.
I recommend cleaning your bed with dish soap, then rinsing it with clean water, and finally wiping it down with isopropyl alcohol.
Increase your Z offset a little to reduce first layer squish and thus bed adhesion and or reduce bed or nozzle temps. Let plate fully cool or put in freezer to ease part removal. Try a different build plate. I have a couple cold or cryo plates which work great for petg at 60 to 70 C but fully release when cooled.
Oddly, on 3D printers, we use bed adhesive to
A: Make things stick to the bed
OR
B: Not stick to the bed too well.
PETG and PET like PEI to a fault, as in they like to become one with it. One way to get it off is gently scrape what you can off and print a ~2-3 layer thick sheet over it (at least 2 layers so you can catch it with the scraper) but lay down the glue first. White Rain (unscented) hairspray is commonly spec’d as the ideal bed adhesive for many materials, but I cannot find it around here.
I seldom use brims for same reason on many materials, as they are 1 layer thick and sometimes cannot be peeled off the bed without heroics, I use the dog ears or a 2-3 layer skirt with zero spacing whenever possible. (Many people have requested the ability to make brims with multiple layers..)
Use adhesive like Magigoo or Layerneer Bedweld. One application is usually good for multiple prints.
These (as well as the hair spray) are water soluble, clean the sheet regularly with hot, soapy water, hot water rinse, follow up with 90% isopropyl alcohol to remove grubby hand/fingerprint oils.
Let the sheet/print cool completely before flexing it, you can take it off and put it in front of a fan/ac outlet etc, should cool off very quickly.
In addition to the great advice above realize build plates are “consumable” and don’t last forever. Amazon and others have self adhesive sheets in PEI, Kapton, Painters tape etc. Build plates are available at MANY price points. AliExpress is a good place to look.