This mission will be slightly harder as we only describe roughly what you'll have to do.
In a previous mission, we have seen how to make automated molten iron cube. But you had to wait for these to cool and collect these blocks manually. Now, we'll make a full automation.
Don't modify the first part you made with Atomic compressors, materializers, sequencer and melting furnace. We'll add a new part after this in order to cool down the molten metal blocks and to store them automatically.
We'll use the slow belt conveyors we made before for handling metal blocks. Make a straight track of 10 belt conveyors at the output of Melting Furnace. The track should be 1 block lower than the Melting furnace. Fill the gaps around the track to avoid the molten blocks to fall.
At the end of the track, place a dematerializer and an atomic compressor behind. These will store the metal bar at the end of the process.
Try your automation by putting the materials in atomic compressors. Once cooled, the metal bars will be stored automatically in the atomic compressor at the end of the track.
Now, your mission is over...