Even though Cybertronian life-forms are quite capable of surviving on purely organic worlds, they sometimes resort to eco-structuring to feel more at home. Eco-structuring is the process of converting a planet into an environment hospitable to mechanical lifeforms, particularly Cybertronians. It can be performed rapidly through devices capable of converting organic matter to technological matter, such as the Key to Vector Sigma. It can also be performed manually in a much more gradual process, such as that performed by the Cybertronian Empire in the construction of the Hub.
It is also known as cyberforming. 
Generation 2 (Marvel Comics continuity)
The Cybertronian Empire, believing organic life to be little more than bacteria and viewing mechanical life as the pinnacle, have been eco-structuring worlds for millennia. They believe this to be construction rather than genocide. The indigenous lifeforms are clinically exterminated, and a metal casing for the planet is manually built. This can seemingly be done quite quickly.
Before War Without End!, Grimlock and his Firestormer team had encountered seventeen "little Cybertrons".