Auto Smelter (self-topping furnaces)

Ore goes in one side, metal comes out the other.

The conveyor filter’s min and max are a target level for the destination, not a transfer size. A max of 500 metal ore keeps each furnace sitting at 500 and tops it back up as it burns down, rather than emptying your ore box into two furnaces at once.

The shape

ore box ──▶ FEED conveyor ──▶ splitter ──┬──▶ furnace 1
                                          └──▶ furnace 2
                                                 │
        output box ◀── COLLECT conveyor ◀── combiner

Two conveyors running opposite ways: feed pushes ore in, collect pulls metal out. One conveyor can’t do both.

Picking a level

Lower (100–200) keeps ore available in your box. Higher (500+) means fewer top-ups but that ore is committed. Start low.

What you need

2 conveyors, 1 splitter, 1 combiner, 4 storage adaptors, 2 electric furnaces, and power for all of it.

Watch out

• Every furnace needs its own adaptor. Four adaptors for two furnaces — one per furnace, plus the ore and output boxes.
• Filter the collect conveyor to metal fragments. Otherwise it pulls unsmelted ore straight back out of the furnace.
• Electric furnaces need no wood, which is why they suit this. A normal furnace would need a second feed path for fuel.
• Scale by adding furnaces, not conveyors. Smelting is slower than moving.

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Not built and measured by us yet. Two things are unconfirmed: whether an electric furnace needs a storage adaptor or has industrial ports of its own, and its 3rW draw.