What is a buffer?

[PTR2013]

Ive heard people talking about "buffers", but i couldnt find any information about it. I searched on the forum and on youtube.

Can anyone tell me what a buffer is?

[sillyfly]

Basically a buffer is any form of temporary storage, separating between a supplying side and a consuming side. When watching a video on youtube, your browser buffers the video (that is - saving some of it on the hard drive before starting to display it), so that if the download speed is not consistent you can still watch the video smoothly.

In the context of Factorio, buffers are usually comprised of chests between two stretches of belts, mostly used between furnaces and supply lines, so that even if your ore supply is intermittent (say, if you are getting it by trains), your factory will still get a steady flow of metal.

[PTR2013]

I think i understand it now, thank you for helping!

[Tallinu]

Another benefit to a buffer, in general, is that once you get to logistics bots, you can change the chests from which the buffer outputs into passive providers, which gives your logistics network direct access to that stored material. They can then bring it to you or to any requester chests you set up whenever required. This can be done without a buffer setup, of course, but doing so often results in a one-way flow into the provider, and depending on the situation, that may or may not be what you want.

Here's an example of a good buffer (just using steel chests, since I don't need my logi-bros moving coal).



I see a lot of people terminating their buffer's inputs as a dead end, relying purely on the inserters transferring material onto the output belts to maintain sufficient throughput for all their base's needs. This turns the buffer into a bottleneck, and bottlenecks are bad.

Having the input belt continue straight through has several benefits: If your input exceeds the trasfer rate of the buffer, it simply passes through as output. When this happens, the output inserters stop wasting power unloading the chests, because the side-loading of the buffer's outputs onto the main belt keeps the buffer outputs full when there's no need for the buffer's extra output.

In the situation shown in the picture, I've just added the buffer, and there are sufficient inserters to consume the entire throughput of the belt, as you can see by the fact that the latter six are idle. But if there was a lot more input, or fewer buffer chests, or more of the chests were full, coal would make it past and directly onto the output belt without the inserters having to spend power transferring it.

If the base were to use material faster than a small buffer could supply it, the pass-through of material would help maintain a greater throughput, as well.

[Peter34]

The problem with Chests-as-buffers is that you need a lot of Inserters (even a lot of Fast Inserters) to completely fill (pump) a Belt - even a normal yellow Belt. The inserter action itself also consumes energy, whereas Belts don't, so I often don't use Chests as buffers, and almost never for Coal/Stone/Ores.

[starholme]

Near the start of the game, I tend to put small buffers on copper, iron, coal. Just a single chest at a corner in the belt.
Later on, generally the only buffers I use are at train stations, to handle the surges of material when each train comes in.

I also tend to hoard vast quantities of various things as an end game goal. But that isn't really a buffer, more of a permanent storage system.

[ratchetfreak]

Near the start of the game, I tend to put small buffers on copper, iron, coal. Just a single chest at a corner in the belt.
Later on, generally the only buffers I use are at train stations, to handle the surges of material when each train comes in.

I also tend to hoard vast quantities of various things as an end game goal. But that isn't really a buffer, more of a permanent storage system.

the reason people use buffers on train stations is because the inserter stacksize bonus only works between inventories and not to/from belts.