[kuba]

Hamsters often chew on the bases or bars of their cage for attention, so this could be a way of him asking to come out of the cage and play?
You could also try putting hanging chew toys along the part of the cage where he is chewing, or generally provide lots of chew toys in the cage for him to gnaw on those instead. If your hamster is quite strictly food motivated, try edible chews like dogtreats or whimzees.
If he continues to chew so excessively maybe pay a visit a vet just to make sure its not anything neurogical, but the only way I could think of to completely eliminate and prevent him from chewing on his cage is to purchase a cage he cant chew on, like a tank or a bin cage.
Hope I could help!