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Notes on a tour of an Amazon distribution facility (2014)

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Re: Notes on a tour of an Amazon distribution facility (2014)

#4

Post by confiscate »

Pretty cool stuff

I wished they would add a diagram, even if it's just hand-drawn. It's would have been much easier to visualize, especially the detailed parts.

Also the naming is sometimes inconsistent across the different authors. e.g. Sometimes folks are called "associates", sometimes "sorters". It got confusing quickly. Would be nice if the naming was clearer

Re: Notes on a tour of an Amazon distribution facility (2014)

#5

Post by pervycreeper »

He doesn't specify exactly how cubbies are selected at the "inbound" stage, beyond saying it's random. I assume it's left up to the associate's own whims and judgements? I imagine the "no identical items in adjacent cubbies" rule improves the potential for picking the same item in parallel while preventing too much concentration, improving availability from different locations. I wonder what other constraints they are given for this stage.

Re: Notes on a tour of an Amazon distribution facility (2014)

#6

Post by Animats »

That's a old manual Amazon facility. The newer ones use Kiva robots to bring the shelving units to the pickers, rather than the pickers going to the shelving units.

The manual system isn't that different from the Sears "schedule system" introduced in 1908.[1] Note the line "pickers don't necessarily pick items for a single or even complete order." That's crucial. Orders are split apart and combined pick lists generated. Picked items then flow towards order assembly stations, which Amazon calls "sort". At any one time, some maximum number of orders are in progress, limited by the number of output boxes at order assembly. Amazon does this with computers; Sears did it with clerks and pick slips, with Sears giving each order an assembly bin for a fixed number of minutes.

Separating picking from order assembly and inserting a sort phase reduces the order of the problem. Picking N orders from M items individually means O(N × M) cost, because as inventory becomes larger, the pickers travel more distance. With separate picking and assembly, performance is something like O(log(M) × N) cost, because each picker works in a limited area. That was Sears' big breakthrough.

[1] https://news.google.com/newspapers?nid=1734&dat=19721006&id=...

Re: Notes on a tour of an Amazon distribution facility (2014)

#8

Post by jonah »

pervycreeper wrote: post #5

He doesn't specify exactly how cubbies are selected at the "inbound" stage, beyond saying it's random. I assume it's left up to the associate's own whims and judgements? I imagine the "no identical items in adjacent cubbies" rule improves the potential for picking the same item in parallel while preventing too much concentration, improving availability from different locations. I wonder what other constraints they ar…

He also implied that the entire stock of an item isn't in the same place. This makes sense - the computer will tell the picker to get an item from the location that's closest to the rest of the items they're picking at that time.

So, you'd think there would be some logic to how the items were distributed and not just the whim of the associate. (Or maybe that's good enough.)

Re: Notes on a tour of an Amazon distribution facility (2014)

#9

Post by michaelbuckbee »

The thing I took away from this was mistake minimization. As shipping the wrong item likely results in a mess of expensive actions down the road, it is much much better to make sure that the right item is shipped the first time. To this end they are willing to shuffle their entire warehouse just to prevent similar items from being set next to each other.

Re: Notes on a tour of an Amazon distribution facility (2014)

#10

Post by tajen »

confiscate wrote: post #4

Pretty cool stuff I wished they would add a diagram, even if it's just hand-drawn. It's would have been much easier to visualize, especially the detailed parts. Also the naming is sometimes inconsistent across the different authors. e.g. Sometimes folks are called "associates", sometimes "sorters". It got confusing quickly. Would be nice if the naming was clearer

On a side note, there are languages such as French where repeating a word is a proof of bad style (and possibly lack of culture from the author), and others like Swedish (e.g. the Millenium books) where repeating is an appeasing regularity.
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