The touchscreen has to be fully working, if there is any defect or doubt when testing, the screen will be rejected.
the display has to be perfect. No fault will be tolerated.
Here are example :
Sometime, a screen can be fully working, LCD and touchscreen. However, a glass that is too cracked represent a risk too high of breakage during the recycling process. The tester will decide not to select a screen with a high risk of non-recyclibility.
We only buy screens with a perfect display. Genuine screen tapes are more flexible more solid than the one from duplicates. However some duplicates have tapes very similar to genuine screens. Some screens are made with recycled genuine screen.
Each screen is tested 3 times on the touchscreen level. If we identify ant default, any trouble, any sensitivity during one of the 3 tests, the screen will be rejected