This mid-game base will produce all 7 science packs at 45 science per minute using 99% mid-game tier components. There is 1 Assembler 3 for Satellite production and stack inserters for blue circuit production, but everything else is based on assembler 2's. The base asks for a red-belt based input of:
8 Iron Ore
6 Copper Ore
2 Coal
1 Stone
1 Pipe of Oil
1 Pipe of Water
At the inputs, I put a splitter array so that excess of each material flows to the other belts, but how you get the ore to the smelters doesn't matter. If you have the plate already made, you can cut out the smelter block, I intentionally made everything fit above the smelters so that those can be removed if the user wishes. Many of the elements come from common methods of material processing, builds for such can be found elsewhere on factorio prints. Many things are near the perfect ratio of production while other things are rounded up on purpose, which is why there aren't nearly enough green circuit factories to support 4 belts, but I'm only trying to make 2.7 belts so it works out. The iron and copper all flow through the Iron Gear Wheels and Green circuits before flowing on to the rest of the factory, using the leftover plate to feed the rest of the factory.
There are no modules or beacons on this build, this is meant to be built from early game on up to the end game. From here you can either try to build a custom mega base that is beaconed, or you can build multiple copies of this base to increase the total science production.