Quick question on crafting speed.

[still__alive]

I just realized I've never considered this. Assembler T2 has a crafting speed of 0.75. Green circuit says it takes 0.5 seconds to craft. So unless my understanding of crafting speed or my math is wrong (which they might be, hence the post) then 1.25*0.5 = 0.625 seconds to craft a green circuit because an assembler T2 crafts at 75% speed.

Now the reason why I'm calculating this is so I know how many T2 assemblers I need to fill a belt without running extra machines I don't need. So if I did the above math correctly, and a yellow belt has a throughput of 15 items/second, then I only need 15 / 0.625 = 24 T2 assemblers to fill said yellow belt. Have I screwed anything up there?

[piccolo255]

Originally posted by still__alive:

Have I screwed anything up there?

A-yup.

If you work twice (2x) as fast, you'll do the work in half (1/2x) the time. So if you work 0.75x as fast, you'll do the work in (1/0.75)x the time. Ergo, circuit production speed is 0.5 [s/item] / 0.75 [1/assembler] ≈ 0.667 [assembler s/item].

Now, if it was 1 [s/item], we'd need 15 assemblers to fill a belt. If it was 2 [s/item], we'd need twice as many assemblers. If it was 0.5 [s/item], we'd need half as many assemblers. Notice the pattern? We need to multiply, not divide!

So 15 [items/s] x 0.667 [assembler s/item] = 10 [assemblers].

(Also notice the units (in brackets). If you divided, instead of items/s and s/item cancelling so you could get assemblers, you'd get 22.5 items-squared per second-squared per assembler :) If you'd like to know more, see: https://en.wikipedia.org/wiki/Dimensional_analysis )

If you're playing modded, you can make it easier for yourself with https://mods.factorio.com/mod/MaxRateCalculator

[piccolo255]

You could also take the opposite approach: instead of seconds per item, use items per second.

In that case, one 0.75 speed assembler making items that need 1 [s/item] can make 0.75 items per second. If it was crafting items that need 2 [s/item], it would craft 0.75/2 = 0.375 items per second.

So crafting speed for circuits is 0.75 [1/assembler] / 0.5 [s/item] = 1.5 [item/s/assembler].

Now it's easy: if an assembler can make 1.5 items per second, how many assemblers do we need to craft 15 items per second? 15 [items/s] / 1.5 [items/s/assembler] = 10 [assembler].

I prefer this approach. Personally, using "items per second" is much more intuitive than using "seconds per item" :) Especially when we get to "items per second per assembler" vs "assembler-seconds per item" :)

[still__alive]

Thank you very much piccolo255, I really appreciate both posts. Very informative on where I was going wrong with my thinking, plus the interesting and useful links. Although I think I'll skip the mod, part of the idea of doing the math on my own is to refresh my math skills and learn new math stuff with something where I can apply it to something interesting.

I'm glad I was wrong too, and was starting to suspect as much. Based on my numbers, I started to realize I wouldn't be able to supply the materials needed to feed that many assemblers, at least not in way that fits in nicely with my desired design, lol.

Thanks :-)

[N'fol]

I tend to have sections supply resources and return the created product from the same side (left/right/top/bottom). By leaving space on the "open" side, I just add more machines as needed. (Even early on, I also leave gaps between each section to leave room for future beacons.)

[THE kilroy]

The good news is that the assembler ratios dont change as long as you have matching assemblers ,only throughput. So when you upgrade assemblers on a particular production line, you may need to adjust your input output belts for flow, but you dont need to recalculate for example how many gear assemblers you need per turret assemblers