So I decided to math out the correct factory ratios for commonly produced items (which people tend to automate). I assume that the crafting speeds of all factories are the same except when comparing Oil Refineries with Chemical Plants where I account for the 1 versus 1.25 crafting speeds. In products that use items made by Chemical Plants but do not involve the Oil Refineries, I effectively assumed that Assembly Machine 3's were used with identical productivity/speed module setups to the Chemical Plants. If you need to rescale the ratios for different factories, you can use a conversion factor on the relevant numbers in the ratios and then multiply out the denominators (more on that in a sec). I did not worry about Furnace products for assembly machine ratios since most people put their plates on the main bus, hence as long as you have enough Furnaces and keep them fed, production won't be bottlenecked by lack of plates.
The Factory Ratios:
Furnace to Electric Miner Ratios:
Iron/Copper:
Stone Furnace : Miners=147:80
Steel/Electric Furnace : Miners=147:160
Stone:
Stone Furnace : Miners=91:80
Steel/Electric Furnace : Miners=91:160
(for Steel Plate production, furnace ratios are 1 to 1 for the same type, stone furnaces are half the speed of steel/electric furnaces, so ratios there are 2 stone to 1 of the other)
Assembly machines (including petroleum products and flamethrower ammo; named for what they are producing):
Transport Belt : Iron Gear Wheel=1:1
Fast Transport Belt : Iron Gear Wheel : Transport Belt=1:5:1
Express Transport Belt : Fast Transport Belt : Iron Gear Wheel : Lubricant*=1:1:5:4
Fast Splitter : Iron Gear Wheel : Electronic Circuit=2:5:5
Express Splitter : Fast Splitter : Iron Gear Wheel : Advanced Circuit : Lubricant*=2:2:5:80:8
Straight Rail : Iron Stick=2:1
Curved Rail : Iron Stick=1:2
Construction Robot : Flying Robot Frame : Electronic Circuit=1:40:2
Logistic Robot : Flying Robot Frame : Advanced Circuit=1:40:16
Repair Pack : Iron Gear Wheel : Electronic Circuit=1:1:1
Solar Panel : Electronic Circuit=4:3
Basic Accumulator : Battery*=2:5
Basic Beacon : Electronic Circuit : Advanced Circuit : Copper Cable=6:4:64:1
(Any) Module 1 : Advanced Circuit : Electronic Circuit=6:16:1
(Any) Module 2 : Advanced Circuit : Processing Unit : (Same) Module 1=6:8:15:12
Speed Module 3 : Advanced Circuit : Processing Unit : Speed Module 2=12:8:15:24
(Other) Module 3 : Advanced Circuit : Processing Unit : (Same) Module 2=12:8:15:30
Sulfuric Acid* : Sulfur*=2:5
Electronic Circuit : Copper Cable=2:3
Advanced Circuit : Electronic Circuit : Plastic Bar* : Copper Cable=40:5:4:5
Processing Unit : Electronic Circuit : Advanced Circuit=15:10:16 (Sulfuric Acid* usage is very low: 0.5/sec total for the 15 PU factories at 1.0 crafting speed; whereas 1 chem plant=6.25/sec)
Engine Unit : Iron Gear Wheel : Pipe=40:1:2
Electric Engine Unit : Engine Unit : Electronic Circuit : Lubricant*=100
5:8
Sulfur* : Explosives*=1:10
Battery* : Sulfuric Acid*=25:2
Flying Robot Frame : Electric Engine Unit : Battery* : Electronic Circuit=40:40:20:3
Land Mine : Explosives*=1:2
Cannon Shell : Plastic Bar* : Explosives*=40:4:25
Explosive Cannon Shell : Plastic Bar* : Explosives*=10:1:25
Rocket : Electronic Circuit : Explosives*=16:1:20
Explosive Rocket : Rocket : Explosives*=8:8:25
Flamethrower Ammo : Oil Refinery (Basic Process)=4:25 (assumes factory craft speed=1.0, assem 3 ratio is 1:5 before modules)
Poison Capsule : Electronic Circuit=16:3
Slowdown Capsule : Electronic Circuit=8:1
Defender Capsule : Iron Gear Wheel : Electronic Circuit : Piercing Rounds Magazine=16:3:2:6
Distractor Capsule : Advanced Circuit : Defender Capsule=15:24:32
Destroyer Capsule : Speed Module 1 : Distractor Capsule=1:1:4
Gun Turret : Iron Gear Wheel=2:1
Laser Turret : Electronic Circuit : Battery*=2:1:6
*=Chemical Plant product, hence crafting speed is fixed to 1.25 before modules
Oil Processing:
Heavy Oil to Solid Fuel : Basic Oil Processing=18:25
Light Oil to Solid Fuel : Basic Oil Processing=36:25
Heavy Oil to Lubricant : Basic Oil Processing=12:25
Heavy Oil to Lubricant : Advanced Oil Processing=4:25
Heavy Oil Cracking : Advanced Oil Processing=1:5
*Light Oil to Solid Fuel : Advanced Oil Processing=54:25 (no Heavy Oil cracked to Light Oil)
**Heavy Oil Cracking : Light Oil to Solid Fuel : Advanced Oil Processing=5:63:25 (All Heavy Oil cracked to Light Oil; all Light Oil converted to Solid Fuel)
*Light Oil Cracking : Advanced Oil Processing=2:5 (no Heavy Oil cracked to Light Oil; all Light Oil cracked to Petroleum)
**Heavy Oil Cracking : Light Oil Cracking : Advanced Oil Processing=1:7:5 (All Oil products cracked to Petroleum)
With some clever use of fractions, you can easily convert these numbers as needed to account for different crafting speeds between factories (and even productivity and speed effects from modules). To do this, choose one of the item type's factories to be the reference value, then compute the ratio of those factories crafting speed (assumed that they are all the same), and each item whose factories are of a different speed (or different productivity), then multiply the corresponding number for the items whose factories are not the reference value by the ratio you calculated for that item (work in fraction form all the way, as it makes the next step a LOT easier). The last detail is to scale up all the numbers to eliminate non-integer values. This is easy if you left the number in fraction form: Just find the common denominator and multiply each entry by that number (and simplify). (I derived the above numbers by hand without a calculator to give you an idea how effective this method is to do by hand or even in your head if the numbers are nice enough).
As an example, consider that you were wanting to make Basic Accumulators with Assembly Machine 1's instead of Assembly Machine 3's. Since the Batteries come from Chemical Plants, we will use their 1.25 crafting speed as the reference value, we need to find the ratio between assem1's crafting speed on the chem plants 1.25 crafting speed. Assem1 has crafting speed of 0.5, so the ratio is 2/5, hence we need 5/2 as many Basic Accumulator factories as the ratio I provided would imply, hence we multiply the number of Basic Accumulator factories by 5/2, giving a new ratio of:
5 Assem1's making Accumulators to 5 chem plants making batteries
We can reduce both numbers by the common factor of 5 to get that we need a 1:1 ratio of assem1's to chem plants (nice isn't it?)
