Factorio Forums

This bug is easily reproducible but is particularly noticeable when using quality modules in your recycler. Simply setup a Recycler with 4 Legendary Quality Modules (though any rarity will do) and recycle Iron Chests. Have the Recycler output into an assembly machine that creates Iron Chests of the same rarity that you plan to insert into the Recycler. I will use common iron chests for this example. Now, when the Recycler generates common Iron Plates via the recycling of the common Iron Chests, it will automatically insert into the assembly machine creating new Iron Chests. However, if the Recycler creates uncommon/rare/epic/legendary Iron Plates, it will instead place it in the first top left slot of the internal storage. This will completely stop the Recycler from working, even if the next item it was going to produce was more common Iron Plates, which wouldn't even enter the internal storage since they get automatically inserted into the Assembly Machine creating more Iron Chests. Additionally, if the Recycler were to generate uncommon Iron Plates, then on the next recycle generate rare Iron Plates, it would still stop working despite having 9 other empty internal storage slots to place those rare Iron Plates into.

The only instance in which the Recycler uses all its internal storage is when recycling scrap without any quality modules. You will see that it uses all slots, 1 for each item. However, even this can be an issue. It looks like the Recycler is designating a specific internal slot for each item. Meaning, even if you insert all the items that scrap can turn into inside its internal storage, but in a random order, it will still immediately stop working until the specific slot(s) are cleared for the item it would be recycling into.

How I expect Recyclers to utilize their internal storage is to fill up every slot until the next item they are producing can't stack with any of the existing items in its internal storage. It should also be able to stack items in any location within its internal storage if the item it is creating already exists somewhere within its internal storage slots.

Those are trash slots, not internal storage, they have to be cleared for it to start a new cycle.

Either way, they don't have to be cleared as you say, as long as the item you are recycling stacks with that item in the same spot in it's trash slots that it was designated to go to. You can have every trash slot filled and it will still work, assuming the item being recycled also designates the same trash slot for the same item. I.e. you can have every slot filled via recycling scrap and still have it work as long as it's still being used to recycle more scrap (no rarity/quality modules being used).