I usually make my transport belts only carry the same items in each lane to avoid blockings, but my goal this time was to have a fully flexible flow with a single looping belt carrying everything.
Overview:
Creating smart inserters:
My first experiments didn't work well because the goal was blue science, and each smart inserter requires 9 circuits.
So I made this specialized section, where lots of circuits can quickly be made, and the inserters are then stepwise refined.
There is a basic 'mixed belt' functionality as blue or purple inserters are put back in the loop by 'b', and yellow inserters are send for upgrading by 'c'.
The mixed loop:
The tricks that makes it work are:
1: The buffer zone. No material should just be left on the looping belt, so each type should be put in their individual smart chests by filter inserters, and put back on the belt by the slow normal inserters.
The slow inserters will not be able to empty the smart chests fast enough when there is too much of a resource, and I can then stop the production of the corresponding resource while the buffer contains e.g. more than 10 of the object.
2: The Reflux and fast belt. I havn't reached the goal of a fully flexible loop, as I sometimes run into trouble if I have more than 4 different resources on a slow belt, as 4 slow inserters can keep it filled. Using a fast belt allows for 8 resources, and splitting half the resources back to the buffer somehow helps stabilize the flow.
This design is not optimized, and there are much more efficient ways for producing blue science, but I wanted to share these results on mixed belts in case it give inspiration to anyone.
