The creation of new Transformers has differed slightly from each iteration of Transformers to the next.
Vector Sigma figures into the mythos as either the source of life (Gen 1), or as a database/oracle of sorts (Beast Wars/Beast Machines).
In Transformers: Prime, Vector Sigma is more of a database - shown
in Orion Pax: Part 3 when Jack and Arcee download information or energy from Vector Sigma to restore Optimus Prime
Furthering the argument that Vector Sigma is not responsible for the creation/life of Transfomers is the fact that
Jack and Arcee need to be guided to Vector Sigma. If Vector Sigma was used with any sort of frequency, one of the Autobots would have known that it was located beneath Kaon.
Both Bumblebee and Smokescreen are referred to as being younger than the rest of the Autobots, and Megatron has a seemingly limitless supply of Vehicons.
So, how are new Cybertronians created or given life?