The storage cathedrals, decoration and packaging

The robots then put the boxes in the conveyors, which move them into the storage cathedrals (click here to see a complete report on them, the following video only has a brief summary). There, the huge cranebots lift them to the heavens, placing them in endless towers of boxes. There are four of these cathedrals in the Lego factory, and no humans are inside. The mainframes know what it is inside at all times, and order the cranebots to retrieve boxes and send them to decoration and packaging, where Lego sets take their final form.

Here, the Lego pieces may take two ways. One is to go straight to the packaging lines. The other is to go into decoration. Decoration is the most expensive part of the Lego process. Here, the pieces are individually painted with absolute precision, like you can see in detail in this video.

In the packaging lines the pieces are distributed: they are dumped into the machine, which separates them one by one, then counts them using optical sensors, and placed in a generic small box. I watched in amazement, seeing how the pieces fell into these small boxes on a very small conveyor. At every step, one, two, three or whatever amount of pieces will fall into the box, according to the instructions of the set in production.

Along the way, high precision scales measure the weight of the box. The computers know exactly how much a box has to weigh at any stage, indicating that the correct number and kind of pieces are inside. If there's a variation of a few micro-grams, the alarm jumps and an operator grabs the box, sorts the pieces, and puts the box back into production.

Once the box is complete, the contents are dropped into the plastic wrapping machine, which makes a bag with the pieces inside. The box are then dropped inside another box, and passed into another production line, where more bags would be added until all the set pieces are in place, ready to be packaged and sent to shops all around the world.

As I watched the boxes going away, being wrapped for shipping, I couldn't help to have this feeling of absolute marvel. From plastic grains to full sets, everything controlled by computers and robots, in a scale that—given the size of most of these piece—stunned me. Next time you look at that Lego box full of bricks, or your collection of mini-figs, think about how complex and elegant the whole production process is. Your "toy" will have then a completely new dimension.