Crypt incursion on servos
It sounds as though you are talking about artifact creature tokens, not just artifact creatures. If this is the case, then your friend is correct. You know it is a token because some effect created them, rather than them existing as actual cards in the game.


  110.5. Some effects put tokens onto the battlefield. A token is a marker used to represent any permanent that isn’t represented by a card.


Note that it is common to use things that look like cards as the markers to represent these tokens, but those things are not "cards" in the sense that a Mountain is a card; they don't go in your deck, etc.

Tokens work differently than cards when they die. While they do enter the graveyard, they immediately cease to exist before you have a chance to do anything such as casting Crypt Incursion. Therefore you cannot exile them from the graveyard.


  110.5f A token that’s in a zone other than the battlefield ceases to exist. This is a state-based action; see rule 704.


Also note that even if the tokens did stay in the graveyard, it wouldn't matter, because Crypt Incursion specifically says "creature cards"; and as mentioned earlier, tokens are not cards.