In my post last week on the new Lego Factory, which now only ships you the pieces you need rather than expensive bags of (too many) assorted parts, I promised I'd find out how the did it. Yesterday I spoke to Michael McNally, Lego's Brand Manager, who explained how they cracked the tricky picking and packing problem of total mass customization.
The answer: they pack the kits by hand, piece by piece. In one of Lego's Denmark factories, one packing station is now dedicated to Factory. The 520 pieces available in Factory are a number large enough to be interesting but small enough to be stored in bins that are no more than a step or two away for the packer. (The previous model used prepacked bags from the Creator series, which it could ship from a US warehouse). As it happened, Lego had recently automated some other parts of its Denmark operation so it had a few extra workers, who it was able to reassign to this job.
It's not a big job so far--only about 3,000 kits have been sold from the 75,000 uploaded--but that relatively small number and high upload-to-purchase ratio may be in part due to the high kit prices imposed by the previous inefficient parts strategy, which could easily double to price of a model. Now that Lego has been able to drop the average model price by 60% with this only-what-you-need packing process, I suspect more people will be tempted to buy what they design.
Next steps, McNally says: more pieces (including more minifigs) and making the software a bit easier to use.