Amount to fully saturate a belt

[Rezznor7]

Hello, I have been reviewing a couple website to help accurately put down the appropriate amount of Electric Furnaces based on the number of Electric Mining Drills I have down using Red Belts.
So a red belt can pass 30 items/second. An electric mining drill produces .5 Ore/second, so to fully fill a red belt I would need 60 drills.
But I am unsure about the furnaces, as they don't really have an amount/second like the miners do, but a crafting speed just listed as 2. Does this mean it produces 2 items per second, correspondingly requiring 2 ore per second?
So for example, I have a small-ish sized patch of ore, and can only fit 12 miners per side end-touching-end, for a total of 24 miners. At .5 Ore/second, the red belt would be passing 12 ore/second down to the furnaces.
Ultimately my question is thus: Would I then only need 6 electric furnaces each side to handle the load? And that is without any modules.

[Galileus]

You are close, but you are missing a crucial detail :)

Crafting speed is the speed witch which a recipe is completed. In this case, it's the "smelt iron"= recipe, and IIRC you can see it in your inventory (even though you cannot craft plates by hand). With a crafting speed of 2, the furnace takes 50% of the time outlined in that recipe to complete it. So: check the plate smelting time, divide by 2, and that will tell you how much time it takes one furnace to smelt one ore into one plate. From there, you should be able to figure out how many plates per second per furnace is produced, and you will be golden :)

[Rezznor7]

Originally posted by Dr. Full Frontal:

You are close, but you are missing a crucial detail :)

Crafting speed is the speed witch which a recipe is completed. In this case, it's the "smelt iron"= recipe, and IIRC you can see it in your inventory (even though you cannot craft plates by hand). With a crafting speed of 2, the furnace takes 50% of the time outlined in that recipe to complete it. So: check the plate smelting time, divide by 2, and that will tell you how much time it takes one furnace to smelt one ore into one plate. From there, you should be able to figure out how many plates per second per furnace is produced, and you will be golden :)

I checked the game, but while in my inventory I could not see where it would tell me the speed of the recipe. I checked the Factorio Wiki however, and it says that smelting an Iron Plate takes 3.2 seconds. So if the electric furnace's crafting speed is 2, that means it takes half as long? So 1.6 seconds. So if I have 12ore/sec coming down the line, that would mean I would need 19.2, or 20 to round up.

[Galileus]

Iron plates and copper plates are right there, in the recipes in the crafting menu attached to your inventory.

Yes, unless I got something woefully wrong, one furnace will take 1.6s per one plate, which gives you a throughput of 1/1.6=0.625 ore per second, which leads to 12 ore per second divided across machines doing 0.625 ops, so 12/0.625 = 19.2 for perfect coverage.

[Nonotorious]

You probably wanna round down if you want the belt to be fully saturated otherwise you will get the occasional gap. Also if you have any modules that change the speed you'll need to remember to change your calcs.
There is 2 times on the recipes iirc, one time from having ingredients and one for making from raw materials.

[astrosha]

Actual Craft time = Recipe time / Machine Speed

Stone Furnaces have a Machine Speed of 1. Electric Miners have a Machine Speed of 0.5. Steel and Electric furnaces have a Machine Speed of 2.

Iron/Copper Ore/Stone/Coal mining recipe Time (not really shown anywhere) is 1 second. Uranium Ore is 2 seconds, I believe, but again, that is not shown anywhere.

24 Miners produce 12 Ore/sec. Ore smelting has a craft time of 3.2 sec. Electric furnaces have a Machine Speed of 2, so 3.2 / 2 = 1.6 sec actual Crafting Time (note that this can and will change when you start using Modules and/or Beacons).

12 items/sec * 1.6 sec/item = 19.2. Round that up to 20 since you cannot have a fraction of an entity.

Personally, I'd make a full sized smelting column. it is not that difficult to set up a train stop to bring additional ore to the smelting column to provide you with a full output belt of plate. Simply use a splitter to input the new ore, prioritizing the miners belt.

[Hedning]

You should try the steel furnaces. They are vastly superior to the electric furnaces. Less than half as big and still craft just as fast, and you can upgrade stone furnaces directly to steel without moving anything.

Use 48 steel furnaces on your red belt. That is exactly the same as stone furnaces on a yellow. Simply upgrade the furnaces and belts at the same time. It is convenience defined.

For small ore patches use a cascade of splitters with priority to push the ore into full belts either right or left priority, your choice. This way you get a number of full belts and one partially full belt. This partially full bet can join the ore from some other patch or simply be used as a spare.

It is always good to have full belts, or at least plan for full belts, otherwise you can get tricked into thinking you have more than you actually have when your factory is intermittently idle.

[gator]

number of machines to saturate belts = (belt capacity) x (cycle length) / (machine speed) / (units per cycle)

example : steel furnaces outputting onto two yellow belts : (30) x (3.2) / (2) / (1) = 48 furnaces.

if you have some set amount of production (like 12 ore per sec) and you want to know how many machines you need to fully utilize it, just divide the input rate by the consumption rate of one machine.

(12 ore per sec) / (1.6 ore smelted per steel furnace per sec) = 7.5 furnaces.

[Vixx]

No, they are using 1 ore every 1.6 sec, so each furnace uses 1/1.6 = 0.625 ore per sec.
So 12 ore per sec/0.625 ore per furnace per sec = 19.2 furnaces

[knighttemplar1960]

I don't want to dampen your enthusiasm but every time you complete a mining productivity research you'll be producing ore "faster". The mining speed rate doesn't change but every time you complete a mining cycle it increases the productivity bar on the miner and when the productivity bar is full the miner produces a free ore and the productivity bar resets. It takes the same amount of time to mine but you produce more ore in the same amount of time as you get mining productivity researches completed this also makes your ore patches last longer.

When the ore under a miner depletes it will also throw your calculations off as that miner won't produce any more. The best thing to do (if you have sufficient power) is to make sure you have the minimum number of miners set out, get production started, and then go back and put miners on the rest of the patch. You'll have idle miners waiting for a spot to place the ore on your belt but when a miner depletes one of the idle ones will take up the slack and your production rate won't change until the patch gets so small that it drops below your minimum ore/sec.

[Khaylain]

AFAIK Mining Productivity adds another bar which fills up at a percentage of the primary mining, and another ore is output when that bar is filled, not when the primary bar fills. The two are independent. So mining productivity actually does make the mining drills produce at a different rate than without. You don't need to fill the main bar to add progress to the secondary bar, it goes continuously.