Massive smelting: Max furnaces per express belt?, etc.

[valenti_scott]

Hello-
I'm currently working on my first mega-factory! One thing which comes up, obviously is smelting of iron and copper, and how to do it efficiently and on a massive scale.

One question in my mind, is, if you have an express belt fed by an e-furnace on either side (for balancing), and you line up the furnaces in pairs down the belt, at what point have you reached the maximum number of furnaces? If you exceed that number, the furnaces further down the belt won't be able to place their output on the belt, because the belt is full.

The math is simple, according to the wiki, the e-furnace can smelt copper or iron at the rate of 0.57 pieces of ore per second. The express belt has a throughput of 40 units per second. Therefore the maximum number of furnaces is 40/0.57, or 70, or 35 pairs of furnaces.

In practice, however, I find I cannot get that high. I was just playing around with a copper smelting operation, and I found that when I reached 46 furnaces (23 pairs), the furnaces furthest down the belt were no longer placing plates on the belt. So I stopped at 46.

Furthermore, when I look at the express belt coming out of my smelting operation, I can see gaps in the belt, as if it is not fully packed with plates. Do belts have gaps which take up less space than one plate, so there is no room for another plate? And so you're not getting the maximum throughput?

Maybe there's something I need to do to pack my belts better... I suppose this has already been covered, discussed, youTubed, etc., but I'm having trouble finding it. In the meantime I'll keep looking, but maybe you can help. Thanks,
-Scott

[daniel0674]

This cheat sheet is the most helpful resource I know of, not just for smelting but for all things Factorio: https://dddgamer.github.io/factorio-cheat-sheet/

Originally posted by valenti_scott:

Furthermore, when I look at the express belt coming out of my smelting operation, I can see gaps in the belt, as if it is not fully packed with plates. Do belts have gaps which take up less space than one plate, so there is no room for another plate? And so you're not getting the maximum throughput?

Maybe there's something I need to do to pack my belts better... I suppose this has already been covered, discussed, youTubed, etc., but I'm having trouble finding it. In the meantime I'll keep looking, but maybe you can help.

The numbers on that cheat sheet and what you calculated (70, or 35 pairs) are the ideal situation (a fully compressed belt without gaps), this is not possible with inserters only. To achieve that compression replace the belt of the last few furnaces with underground belt, so that the inserter drops it on the underground belt instead. Factorio has a little quirk (this is not a bug) where inserting on an underground belt prioritizes the items and they will completely fill the gaps and push items already on the belt a little bit further back.

This image shows what I mean: https://puu.sh/y68Be/2c085d442f.jpg

[piccolo255]

If you don't like tricks with underground belts :) and don't minding wasting a little bit of space, there is another way...

When an inserter is placing item on a belt, it requires enough space to put it down. However, the gaps left from upstream are often too small for that, so the belt will be full of tiny gaps while downstream furnaces are unable to offload.

OTOH, when you "sideload" one belt onto another, whenever there is any gap, however small, in the main belt, the side belt will place an item there. If the gap was smaller then one item, then the main belt will lurch for a bit to create enough space.

Therefore, if you unload furnaces on side-belts which connect to main belt instead of placing item directly onto main, you can nicely compress the belt.

This takes more space than using underground belts like daniel showed, but for some reason I find it more satisfying... I guess it just looks nicer

[Warlord]

Originally posted by valenti_scott:

In practice, however, I find I cannot get that high. I was just playing around with a copper smelting operation, and I found that when I reached 46 furnaces (23 pairs), the furnaces furthest down the belt were no longer placing plates on the belt. So I stopped at 46.

Furthermore, when I look at the express belt coming out of my smelting operation, I can see gaps in the belt, as if it is not fully packed with plates. Do belts have gaps which take up less space than one plate, so there is no room for another plate? And so you're not getting the maximum throughput?
-Scott

Yep, I use 32 pairs of furnaces, or 64 total. On the last 6 or so pairs I start doing underground belts where the inserters dropoff for the trick that Daniel mentioned.
http://steamcommunity.com/sharedfiles/filedetails/?id=1136112579

[valenti_scott]

Thanks guys, I like all these ideas, under-grounding, side-loading and cheat sheet. Don't know about bots though! Ha ha
-Scott

[brian_va]

14 is the correct answer

https://imgur.com/a/Sf9ZY

when you are at mega scale or even approaching it, power should no longer be an issue. have a dedicated solar area, feed it the raw resources by rail, drop a blueprint every so often and let your bots build it.

[Snacking]

Originally posted by brian_va:

14 is the correct answer

https://imgur.com/a/Sf9ZY

when you are at mega scale or even approaching it, power should no longer be an issue. have a dedicated solar area, feed it the raw resources by rail, drop a blueprint every so often and let your bots build it.

Why do people choose solar over nuclear?

[brian_va]

when going big it is better for ups, 10 billion panels is 1 entity.

and space is not an issue.

[Hedning]

I recommend not trying to fill belts but have excess. Production changes as you use beacons and modules. Just keep lanes short and feed each into a large balancer where you can merge them into fewer belts.