An Atomic Assembler copies blocks or items using power.
First put 6 strange matter in the outer circle then put the item or block you want to copy in the middle.
Then connect power into it from the top. Then right click and you will start copying. Over time once it's 100% it will keep making copies. The items stay in the device and you can take therm out when you're ready.
You can also use an ME system to remove them automatically.
Tekkit Atomic Assembler Tutorial Duplicate Items in Tekkit main Atomic Science