LEGO, the Danish toy manufacturer, is quite possibly the largest captive molder in the world based on number of injection molding machines and number of plastic parts produced.
Captive molders famously will not reveal the number of machines they operate for competitive reasons, but suffice it to say that LEGO owns and operates several thousand Arburg injection molding machines (150 tons and under) at its three plants in Denmark, Hungary and Mexico.
LEGO began using ABS, a low end engineering plastic, in the early 1960s soon after it developed its load-and-lock brick design that has been its bread and butter ever since. Previously the company had molded bricks with cellulose acetate, but needed the stiffness of ABS for the new design. Arburgs are used because the design requires very tight tolerances (2 micrometers) that are repeatable billions of times over. The company molds more than 30 billion parts per year.
In an interesting analysis in a new book on LEGO called “Brick By Brick,” innovation professor David C. Robertson makes the case that LEGO bricks may have become overpriced and are subject to a competitive threat from bricks made via 3D printing.
Using a MakerBot Replicator and ABS plastic, his son produced an architectural model similar to one produced by LEGO at one-tenth the cost of a Lego kit. Some of the savings came because less ABS used in his son’s bricks. According to Robertson, the Lego kit cost 15 cents per gram, three times the cost of the ABS used by the MakerBot. And you can bet your bottom dollar that LEGO is paying less for ABS that Robertson’s son did.
It’s not clear how the quality compares, but Robertson makes this conclusion: “As 3D printing improves, LEGO might one day find that Minecraft (or something like it) has jumped the digital divide to become a more compelling, richer, and easier way to construct plastic buildings, characters and vehicles.”
Not exactly a manufacturing revolution, but very interesting.