Baby won't nap

Having a really hard time getting my 6 week old to nap. He gets mad due to sleepiness and it's hard to get him to sleep. At night I just lay him in the crib awake and he goes to sleep no problem. Durring the day though, I try rocking, walking, car rides, swing. Nothing. Just a cranky baby. Any tips?  I would love for him to sleep in his crib. Thanks.