In design school we toured a Lego factory in a Samsonite plant; the ex-CEO was our marketing professor and he had negotiated North America rights, since reclaimed by Lego.
It was fascinating, and probably learned more in one half day visit than entire semester. Some of the 3 video's contents is identical to what we saw in 1984!
- Molds (core-cavity set) came from Billund and were returned there after maximum cycles.
- Sheet extruder processing blue styrene and shearing pieces to length. There was an automated rotary station doing vacuum forming, demold, Lego piece fill and package.
- Saw random piece packaged sets by weight, almost identical as in the video.
Trivial, but to a know-nothing design student, seeing automated high volume manufacturing using weight instead of part count, and the in-situ extruder-automated packaging station was a real lesson in alternate ideas.
A real thrill when we were allowed to dig our hands in and keep some still warm fresh Lego pieces. That Lego 4X4 yellow brick was on my keychain for about 10 years.
In video #2 showing the overmold dice tool, observe the guy sliding the molds' side action: see the angled faces, also seen but blurry on the mating mold part to the right. Another impromptu lesson - non powered sliders in an injection mold tool. Obvious when you see them, otherwise a young designer has no clue of undercuts, side action, etc.