You have a fuc*ton of ores and cant melt them? Dont worry, we got you.
Deliver Ores via 1-4 Trains and get your plates. It kinda melts 10'000 plates per 5 sec if you deliver enough ore. Screenshot: input on the bottom, output on top. (Balancer are there so "if" the input isnt even, so you could input directly from ore-deposit + deliver by train. But its not best to do that.)
unloading station shuts down if there is enough ore, except for the last one, so the trains can wait and hopefully wont backup (but, if the first 3 are closing and a train is arriving he maybe just pass by and re-path so he turns around and around. Its a good idea to make a closing loop of the output to the input). the loading stations only opens if there are over 16k metal plates in storage (except for the last one).
give the station the same names. load and unlaod. if you try to melt copper you have to reconfig the counters/circuitnetwork (from metal to copper).
credits:
smelter-rows: https://factorioprints.com/view/-KogJ8c9HZT3nJRErsIz
balancer: https://www.reddit.com/r/factorio/comments/56hqfq/improved_12_to_12_balancer/
unloading: https://www.reddit.com/r/factorio/comments/69j7eg/train_unloading_in_0157_improved/
loading/train: by myself
thanks to bm