Domain name availability

I searched for how long after domain registration expires available and I get many answers written for the current owner of a domain name but I find nothing written for someone intending to purchase a domain name that has expired. An article in says that a domain typically enters Redemption about 45 days after its expiration date if it is not renewed or purchased by a 3rd party and that implies it can be purchased before the 45 days is up, therefore it is confusing.

For a com TLD, how long after the name has expired does it become available for purchase? I realize that there are very big companies that specialize in swooping up domain names and therefore I am not likely to get a good domain name even if it expires and becomes available for purchase, but I am at least curious.