From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
In the anime, Toei Animation added this character into the story in order to showcase the mastermind behind No. 8's creation. Doctor Gero was yet to be created as a character during the Androids Saga as the chief scientist of the Red Ribbon Army and the one true person behind the creation of the Artificial Humans. Dragon Ball: Daizenshū 7 addresses this inconsistency by stating that Frappe and Gero might have been colleagues in charge of the Red Ribbon Army's Android Development Program.
Frappe appeared in "The Secret of Dr. Flappe". After Son Goku and Artificial Human No. 8 conquered Muscle Tower, the both of them and Suno set out to remove the bomb implanted within No. 8. Suno informed Goku that they should visit Frappe, an expert in machines. After a last ditch attempt by Master Sergeant Murasaki to steal the Dragon Balls, a successful operation on No. 8, and a great scare as the bomb was very nearly dropped, No. 8 was safe from the Red Ribbon Army's clutches once more. Frappe, at the very end of the episode, silently admitted his cowardice and longing to tell No. 8 that he was the one who had placed the bomb within him in the first place.