LEGO Bricks Demonstrate Exceptional Compression Resistance. LEGO bricks are renowned for their versatility and durability, but a surprising aspect of their design has come to light: exceptional compression resistance. With some bricks capable of withstanding forces up to 4,250 newtons (958 lbf), LEGO has inadvertently created a material that rivals conventional building materials. This article delves into the research behind LEGO’s impressive compression strength and explores potential applications in construction, architecture, and beyond.
A Brief History of LEGO
The story of LEGO began in 1932 when carpenter Ole Kirk Christiansen started a small workshop in Denmark to produce wooden toys. Through his incredible tenacity and passion for toy-making, Christiansen built a successful company after suffering numerous setbacks. He soon renamed his company LEGO after the Danish phrase leg godt, which means “play well.”
After World War II, LEGO transitioned from wood products to plastic due to material shortages. Despite bans on plastic products due to these shortages, Christiansen bought Denmark’s first plastic injection molding machine.
Injection molding, a process developed in the 1930s, allows mass production with high precision and consistency. LEGO integrated this technology into their manufacturing processes in the late 1940s, resulting in bricks that featured consistent dimensions, improved structural integrity, and enhanced clutch power. Through this technology, they were able to release the first interlocking brick, the aptly named Automatic Binding Brick, in 1949.
However, as LEGO expanded its product range, injection molding played a vital role in creating intricate elements like minifigures, wheels, hinges, and gears, adding realism and imaginative possibilities to LEGO sets.
Today, LEGO continues to invest in advanced molding machines, precise tooling, and research new materials to maintain the highest standards of quality and playability. From its humble beginnings to becoming a global toy empire, LEGO’s journey is intertwined with the advancement of injection molding technology, enabling builders of all ages to unleash their creativity and build extraordinary worlds.
How the LEGO Group Manufactures Its Iconic Bricks
What plastics does the LEGO Group use to manufacture its bricks? LEGO uses a variety of materials to manufacture different products. But their classic blocks are made from a specific type of plastic called acrylonitrile butadiene styrene (ABS), a polymer known for its durability and versatility.
Manufacturers produce Lego bricks from hard plastic.
These plastics are called acrylonitrile butadiene styrene (ABS) with a manufacturing tolerance of roughly 0.01mm. “Lego bricks are very precisely made,” says Barnaby Gunning, the London-based architect who designed May’s house. This precision makes them a reliable and efficient construction material.
The ABS is semi-pliable, allowing bricks to fit together using a friction-dependent connection called a snap-fit. The friction between the top stud of one brick and the interior tubes of the brick atop it holds the pieces together, but not so much that they’re impossible to pull apart.
Now, to look at Lego bricks as a building material, picture a Lego skyscraper and measure the brick’s strength against the forces that architects and engineers design buildings, bridges, and other structures to withstand. Different loads impose compression, shearing, and tension forces on a structure. These loads can include the weight of the building’s materials, rooftop snow accumulation, gale-force winds, or the sudden shudder of an earthquake.
Lego blocks can withstand impressive compression (compacting) forces
In 2012, researchers at England’s Open University tested the strength of a 2×2-stud Lego brick using a hydraulic press. The brick held up a staggering 950 pounds of force before failing. That strength, in theory, could support about 375,000 other bricks, or a tower just over two miles high. They’re also adept at resisting shear (sliding) forces; the stud-and-tube design locks the pieces in place to keep them from sliding from side to side. But tensional (pulling) force is the block’s structural weakness: Under tension, they begin to separate, and the structure collapses.
Our skyscraper of blocks, held together only by stud-tube friction, suffers from this unfortunate news. “The friction is just not enough to withstand, say, an earthquake or an extreme windstorm,” says Stephen Ressler, PhD, a mechanical engineer and professor emeritus from the U.S. Military Academy at West Point.
A bridge made from Lego bricks
During a hurricane, the wind might push against the wall of a house and begin to lift the roof. As the roof lifts off the structure, it creates a suction force that bends the wall and loosens the joints near the ground. In a house of Lego bricks, these forces would tear the ABS blocks apart. Similarly, in an earthquake, ground shaking might cause our high-rise to sway from side to side. As the tower bends, the blocks separate and lose the frictional force that holds them in place.
Hence, as the height of our skyscraper increases, its stature acts like a lever to amplify tensional forces. Lateral loads applied to the top of a tower increase tensional stress on the bottom joints as the tower’s height increases.
A bridge made from Lego bricks would face a similar issue. While the connective joints along the top of the bridge’s span experience compression as they take on a load, the joints on the bottom of the bridge experience tension, open up and fail. Gunning’s team faced this struggle when building May’s Lego home.
To ensure the second story would be strong enough to hold the weight of May and his film crew, the team tested different beam designs to see which one could best resist these tensional forces. (At one point, the film crew, unhappy with the slow nature of one beam’s deformation, asked Gunning’s team to toss bags of gravel onto the beam.) The sturdiest design, a vertical stack of bricks laid horizontally within a beam, withstood twice the amount of weight as their previous designs.
