No one here in the user community can know anything about "when", but we can tell you how to investigate.
First, if you efiled, be sure your efiled return was accepted. If using Online TurboTax, you can check at the Tax Home page.
If the Tax Home page showed your return was accepted, you can track your Federal refund at the IRS "Where's My Refund" tool. What message do you see there?
https://www.irs.gov/refunds