Factorio Forums

How can you make entities that are not already supported in vanilla factorio
Like a assembler that can only make a few recipes (aka a centrifuge)

Sure, that's already supported by Factorio. You'd just make a new crafting category and have the new 'centrifuge' and it's recipes use it
As for things that aren't supported by Factorio, it's usually possible with some understanding of Lua and Factorio's modding API.