Yes you need them to build anything. You get a use by contacting the faction that owns the DC, and paying them for the use. They then assign the datacard to a factory, shipyard etc and then you can start production once you have NPCs and raw materials ready.
Certain types of Factions have "Default Cards" like Ship builders get the Escape Pod. Medical factions get ALL the cards dumped on them since I believe they have to have other factions produce all of them.
Her imaginary friends think you have issues. Her multiple personalities agree. So her inner child is refusing to speak to you!
So the ones that give naturally are Ships, mining, medical and recycling ( spelling fail) But arent i allowed to use any data card in a factory? Then it would be alot easier to be a recycling faction as i can produce for items of worth right?
Don't forget Smugglers, droids and weapons/items. You can use factories to produce anything as long as it follows the producing rules. Also the faction type for the DC you are building for and size (if it's a ship type).
I work for a ship company, I am building medical ships in a factory and soon my SY.
Recycling can build fighters, like the X-ceptors/Y-ties.