In Factorio, I have a belt running around countless assembling mashines, carrying all the resources those need. Unfortunately, the belt mostly fills up with one or two resource types, halting all production.

Should I try to limit production rates to desired levels, or should I try to remove unwanted items? Currently the belt circles around, so items remain in the belt until needed.

  • 3
    Unless you're deliberately trying to challenge yourself by making this kind of "sushi belt" design, this really isn't a good way to set up your factory. You'll be much better off if each belt is dedicated to one or two (one on each lane) types of resources. As you've discovered, a mixed belt is very hard to keep in balance.
    – Paul Z
    Jan 1, 2021 at 19:40
  • 1
    Yeah, 2 weeks into the game I came to the same conclusion. It's a pity, as I can't easily switch factories from one product to another. Sushi should be the solution to all problems though.
    – Zsolt
    Jan 3, 2021 at 13:52
  • 2
    "Switch[ing] factories from one product to another" isn't really the intended style of Factorio. You make a factory that makes something, and now you have that thing available. If you want a different thing, you make some more factory; you don't demolish the stuff you already have.
    – Paul Z
    Jan 3, 2021 at 17:47

1 Answer 1


You can attach circuit wires to belts. Here's an example of what that looks like:


That gives you two abilities:

  • Enable/disable
  • Read belt contents

You can use these to selectively allow items onto the mixed belt when there aren't enough of that item. You can also read the contents of the belt and remove items when there's too much of one item. According to the wiki, a straight belt can hold 8 items (using both sides), so you might have some filter inserters automatically remove some items if there's more than 2 of that item in a given belt section.

  • I'm intrigued by this idea, but do you know of any working examples? Would it be one filter inserter per item (hence a row)? What about putting them back on the belt if there aren't enough? Then maybe a pair of inserters per item?
    – dfrankow
    Feb 7, 2021 at 4:12

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