Make your recyclers stack their outputs!

[kpreid]

Recyclers are capable of placing item stacks onto belts, but they won't if the belt is not backed up. This wastes belt capacity. Here’s a simple trick to make recyclers output mostly full stacks:

Recyclers.jpg (3.1 MiB) Viewed 639 times

Each recycler is set to “Read working”, and wired to its own dedicated belt segment which is set to be enabled only when the recycler is not working. This way, each recycler fills up its own inventory until it is out of room in some output slot, then the belt advances emptying all of the recycler’s output slots until that one slot has space again, and the cycle repeats. This produces many more full stacks of items than partial stacks, as you can see in the screenshot.

Of course, this means that your recyclers will be working at less than 100% duty cycle, so you need more recyclers per unit of scrap (improving if you upgrade the output belts), but you may still find it more space efficient if it lets you use fewer belts, particularly in a belt-based sorter. Or maybe you just like seeing fully stacked belts.

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[pioruns]

Amazing idea, thanks for sharing!

[pioruns]

I've tested it, and it works. Recycler buffers fills up with, for example 100 cogs and many other items, which are being unloaded into the belt fully stacked, when Recycler stops (being full).

But, for some reason, if Recycler has Quality modules, Recycler doesn't want to output anything into the buffer, when belt is disabled. It wants to output things immediately onto the belt, and stops very often, even with Buffer empty. Anyone knows why?

Recycler with Quality modules:

08-28-2025, 11-06-40.png (241.51 KiB) Viewed 563 times

Recycler without any Quality modules:

08-28-2025, 11-06-59.png (285.33 KiB) Viewed 563 times

[Tertius]

Instead of letting the belt back up, you can use stack inserters to explicitly build stacks:

08-28-2025, 13-59-00.png (147.07 KiB) Viewed 528 times

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The constant combinator provides a -15 for every possible recycler result, which adds to the recycler content, so as soon as a full hand load of 16 accumulated, 16-15 = 1 (a positive number) appears as result, and this is used as filter for the stack inserter. So the stack inserters just start to grab items if at least 16 of one material is present in the recycler. No quality required, it's just to check for higher speeds. Since stack inserters grab items from an inventory instantly, there is always 1 inserter getting all 16 and the other 0, not both inserters 8, so you can just provide every inserter with the same filter.
If you use different wire colors as in the screenshot, so the signals are isolated, you can use 1 global constant combinator for all your recyclers.

@pioruns:
The recycler will stop if the current crafting cycle produced an item (in your screenshot: due to productivity), and there is something with a different quality already in the recycler inventory. It seems it cannot put the finished item into the inventory in this case. Difficult to handle this case in combination with item stacking.

[computeraddict]

But, for some reason, if Recycler has Quality modules, Recycler doesn't want to output anything into the buffer, when belt is disabled. It wants to output things immediately onto the belt, and stops very often, even with Buffer empty. Anyone knows why?

If it rolls a different quality output than the one that's queued in the output it can't stack the different qualities, and has to stop

[pioruns]

But, for some reason, if Recycler has Quality modules, Recycler doesn't want to output anything into the buffer, when belt is disabled. It wants to output things immediately onto the belt, and stops very often, even with Buffer empty. Anyone knows why?

If it rolls a different quality output than the one that's queued in the output it can't stack the different qualities, and has to stop

That's very unfortunate. I don't see reason why would it behave like that. A simple chest placed next to the Recycler works correctly, but the internal Recycler buffer cannot. I've solved Recycler with Quality output stacking by introducing simple steel chest:

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Now, every Recycler can output everything perfectly stacked in 16s, including all Quality products. Unless Steel Chest is full due to too many item variations, I will see if upgrading to legendary Steel Chest helps with that.

Screenshot_20250828_214256.png (191.23 KiB) Viewed 418 times

[computeraddict]

I don't see reason why would it behave like that.

It's exactly how every other production building works with quality

[kpreid]

The recycler will only use the output slot corresponding to the position of that product in the recycling recipe — and so the recycler has 12 output slots because the scrap recycling recipe has 12 products. I don’t recall whether it was in FFF or the forum, but someone from Wube said that this is an intentional design for computational efficiency. (Perhaps to do with the 2.0 support for multiple crafts per tick, to avoid having to search the slots after every craft?)

So, any time a different quality of a specific product appears, that one output slot has to be empty, and it doesn't matter whether there are other slots open.

[pioruns]

Thanks for the explanation.
I worked around it by placing a Steel Chest in front of the recycler and using a blueprint above. With 60+ slots, the chest never overflows—Legendary ones have 120, so this setup runs indefinitely.

You don't get quality items from Recyclers? I do—it's basically a free upgrade.

[kpreid]

I used to put quality modules in all my Fulgora recyclers, but I found that the high quality items were taking away capacity from everything I wanted to do with normal-quality items. Perhaps they would be valuable if I split all my various production lines to support intermediate quality inputs, but that's not what I’ve chosen to do (on this save). So, on Fulgora I have two sets of recyclers — normal scrap goes to recyclers without quality modules, and quality scrap goes to recyclers with quality modules to upgrade them further. And excesses of normal items after scrap sorting do get thrown in quality upgrading recyclers too. In the end, the only legendary materials I’m short on are uranium and tungsten, which you can’t get starting from scrap.