How Are Plastic Bricks Made?

Plastic bricks for toys, etc., must match, and so, they have to be manufactured very accurately. LEGO uses moulds, which are designed with a degree of accuracy of 0.005 mm or less than 1/10 of the width of a human hair.

PLASTIC GRANULATE

Plastic granulate – large “grains” of plastic of the same colour – is heated to 230-310 °C. The hard plastic grains fuse into a coherent mass with a texture like that of dough. Some LEGO bricks such as the legs of a figure are made of several separate parts, which must be joined. Machines apply very accurate, variable pressure. At the same time, the face of the figure’s head is printed.

MOULD

The soft plastic is placed in moulds and subjected to a pressure of up to 150 t. The pressure varies according to the type of brick. The brick cools for about 10 seconds, after which it is forced out of the mould.

COMPLETE BOX

The boxing of different elements is computercontrolled. A conveyor belt carries boxes to containers with different elements, which release the correct number of elements into the boxes.