Although my print quality is OK, all objects don’t seem completely flat when removed from the printbed.
The corners are not coming off the printbed but there is a slight curve, so e.g. two parts off a box always have a slight gap in the middle while the corners fit nicely.
Can a heated printed help in this case?
Or is there another solution?
This happens when the object doesn’t stick correctly on the bed. First be sure to have 0.2 mm at most between your nozzle and the bed (everywhere as the bed is often bulging in the middle). PLA should normally stick without a heated bed but ABS won’t. With a heated bed you can use a special spray to get your objects sticking (ABS in particular). I’m using Dimafix and even big ABS pieces stick like hell.
Same problem here (with larger objects)
Probably caused by thermal stresses?
I think a heated bed is indeed the way to solve this.
All objects seem to stick just fine, even the corners, I have a hard time getting them loose from the printbed.
It’s more like it seems that the printed objects have some inner tension that warps the object a bit once they are removed from the printbed.
Just ordered a custom heated printbed from Marlark, I’ll try that to see if the results are any better.
I think Raby already said this before 
Some of us have been testing Dimafix on heatbeds and after 2+ months of testing it i can also recommend it alot. It is very good to use for it is simple to print on and simple to get the item off when it cools down under 50C. The bottom layer dont get contaminated by other solutions like painter tape residue or patterns or residue from glues and slurries and other solutions. For the most you can actually remove the item and just print again wish is good without having to clean and reapply dimafix every time.
I have been looking on your item there by zooming on the picture. just looking on the photo it looks like it warps on all directions both to X and Y. As others have stated a heatbed will solv this for you pritty good. Im turning your bed in probably tomorrow or on monday. Dont matter in term of speed getting to you sins the delivery guys is slackers during weekends like the rest of us 
Ordered a SSR the other day based on a suggestion from Raby instead of using a PE. Going to be interesting to try that out.
// Marlark
Ok, Solid State Relay and Power Expander…
It’s over 30 years ago since I was taught that at school…gotta dig deep 
I’ll try the DimaFix once I have your printbed installed.