Federer won all 16 of his service points in the first set and closed out the match in 68 minutes, sending a clear message to his rivals that he is in top shape heading into the year's final grand slam at the Aug. 25-Sept. 8 U.S. Open.
The 33-year-old Swiss, in a rematch of the Wimbledon semi-final that he won in three sets, improved to 6-0 against the Canadian fifth seed and will be playing in his second final in seven days after he lost to Jo-Wilfried Tsonga at last week's Rogers Cup in Toronto.
For Raonic, 23, his usual booming serve produced six aces to Federer's two, but he also had three double faults compared to none by his opponent.
He put a bit of a dent in Federer's serve in the second set but the Swiss managed to break serve for a third time in the eighth game of the second set, clawing back from a 0-40 hole, to record the straight sets victory.
"I'm playing much better (than last year). I can move freely again," Federer told ESPN after the match.
"I'm happy the results show. It's more fun playing this way. Now I am playing the right way.
"It's great for the confidence to switch from clay to grass and hard courts and keep on playing well. I've had a very complete season so far.
"This is my eighth final of the season. I hope I can win another final here."
Sixth seed Ferrer, playing his first semi-final in 11 trips to Cincinnati, breezed past Frenchman Julien Benneteau 6-3 6-2 to move one win away from his 22nd title and second of the year.
Ferrer, who has reached at least the quarter-finals of all four tournaments he has played since crashing out of Wimbledon in the second round, needed just 71 minutes to earn his sixth victory in 10 meetings with Benneteau.
The 32-year-old Spaniard saved the one break point he faced and did not double fault all match long against Benneteau who was coming off a surprise win over third seed Stanislas Wawrinka.
"Of course I am in a good moment," said Ferrer. "I am in my first final this year in a Masters 1000, so I'm happy for that. (I take it) step by step and focus for tomorrow."
Federer enters Sunday's final having won all 15 meetings with Ferrer, the most recent being a three-set victory in the Toronto quarter-finals earlier this month.