Mod moved! See here: https://mods.factorio.com/mod/SimpleCompress

This mod lets you compress and decompress iron, copper and steel plates. 20 items into 1 package. You need at least blue assembler to compress, but you can decompress with machine or hand-crafting.

By sending packaged plate products around your base with robots, you can create localized storages for the actual plates. It will also reduce item traffic which helps to improve UPS/FPS.

This is a standalone mod, but companies my other mod; Ore compress
https://mods.factorio.com/mods/Zaflis/OreCompress