How to avoid baby from bumping the baby crib and banging his head on the wood crib?

How old is LO? If baby still doesn’t know how to flip, generally they won’t hit their head. And since you have the bumper already, it should be fine. If he’s doing it on purpose, he’s having a meltdown. You can try to explain to him like it’s okay to feel upset etc etc. I’m a rather chill mum so as long as it’s not those bang until need go hospital kind, I’m ok with it. Overtime my LO knows that when she hit her head it’s painful so she won’t do it again.