How Lego Bricks Work


The simple 2 x 4 Lego brick. See more toy pictures.
Photo courtesy Lego

Nathan Sawaya has created a life-sized replica of Han Solo frozen in carbonite. He's also made an 8-foot-tall pencil, a Statue of Liberty holding a lightsaber, a Golden Gate bridge and a Tyrannosaurus Rex. And he's done it all with Lego® bricks.

What does it take to turn a pile of 10,000 bricks into Han Solo? Where do the bricks come from, and what makes them stick together? And how did a free-form building system evolve to include programmable bricks, replicas of the Death Star and the Batmobile, and printed instructions?

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In this article, you'll learn lots of brick basics as well as how Master Builders and devotees make enormous creations out of tiny bricks.

Most Lego pieces have two basic components -- studs on top and tubes on the inside. A brick's studs are slightly bigger than the space between the tubes and the walls. When you press the bricks together, the studs push the walls out and the tubes in. The material is resilient and wants to hold its original shape, so the walls and tubes press back against the studs. Friction also plays a role, preventing the two bricks from sliding apart. This stud-and-tube coupling system uses an interference fit -- a firm, friction-based connection between two parts without the use of an additional fastener.

All of the basic Lego elements use this principle to stick together. They come in a range of shapes and sizes, including wheels, windows, doors and studless tiles. But the basic elements are all variations on the basic brick. You can learn about the basic Lego elements in our field guide below.

In the next section, we'll look at how Lego bricks are made.

Making Lego Bricks

Basic Lego elements begin as blue, black, dark grey, green, light grey, red, yellow and white.
Basic Lego elements begin as blue, black, dark grey, green, light grey, red, yellow and white.
Image courtesy ©Lego

All of the basic Lego elements start out as plastic granules composed primarily of acrylonitrile butadiene styrene (ABS). A highly automated injection molding process turns these granules into recognizable bricks. The making of a Lego brick requires very high temperatures and enormous pieces of equipment, so machines, rather than people, handle most of their creation.

When the ABS granules arrive at Lego manufacturing facilities, they're vacuumed into several storage silos. The average Lego plant has about 14 silos, and each can hold 33 tons of ABS granules. When production begins, the granules travel through tubes to the injection molding machines. The machines use very accurate molds -- their precision tolerance is as little as 0.002 millimeters.

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The machines melt the granules at temperatures of up to 450 degrees F (232 degrees C), inject the melted ABS into molds and apply between 25 and 150 tons of pressure. After about seven seconds, the new Lego pieces cool and fall onto a conveyor. At the end of the conveyor, they fall into a bin.

The injection-molding process uses large, heavy molds that are manufactured in Germany.
The injection-molding process uses large, heavy molds that are manufactured in Germany.
Image courtesy ©Lego
Molded elements fall into bins and wait for a robot to carry them to the assembly hall.
Molded elements fall into bins and wait for a robot to carry them to the assembly hall.
Image courtesy ©Lego

When the bin fills, the molding machine signals a robot to pick it up and carry it to an assembly hall. In the Billund factory, eight robots move 600 bins of elements per hour. In the assembly hall, machines stamp designs onto bricks and assemble components that require multiple pieces, like minifigures, also called minifigs. The machines assemble the components by applying precise amounts of pressure to specific parts.

Machines assemble components that require several pieces, like minifigures
Machines assemble components that require several pieces, like minifigures
Image courtesy ©Lego

From there, the elements go into packages, as we'll see in the next section.

Lego Testing and Packaging

Finished Lego elements wait to go into packages in a storage facility in Billund, Denmark.
Finished Lego elements wait to go into packages in a storage facility in Billund, Denmark.
Image courtesy ©Lego

If you've bought a Lego set -- whether it's a box of assorted bricks or a set meant for building something specific -- you've probably noticed that the box includes several bags of bricks rather than a large pile of loose elements. These bags are part of the automated packaging process, and they help make sure that the right pieces go into each box.

Quality assurance testing ensures that Lego parts are durable and will stand up to lots of play.
Quality assurance testing ensures that Lego parts are durable and will stand up to lots of play.
Image courtesy ©Lego

During the packaging process, bins open and close automatically, dropping precise numbers of bricks into each polypropylene bag. A machine weighs these bags to make sure their contents are correct. If a specific bag's weight is incorrect, an operator can replace that bag, rather than having to discard an entire set.

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LEGO testing and packaging involves drop, torque, tension, compression, bite and impact tests.  Read more about how LEGO toys are tested and packaged.
LEGO testing and packaging involves drop, torque, tension, compression, bite and impact tests. Read more about how LEGO toys are tested and packaged.
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At the end of the process, packaging operators fold the boxes, add any necessary pieces and make sure that the machines haven't made any mistakes. The sealed boxes are stored and shipped around the world -- the process uses between 400,000 and 500,000 cardboard boxes per year.

Quality assurance testers also perform numerous inspections and tests on Lego elements. Machines perform drop, torque, tension, compression, bite and impact tests to make sure the toys are sturdy and safe. Technicians use a measuring beaker to determine whether pieces could cause a choking hazard for small children. For every million Lego elements, about eighteen, or 0.00002 percent, fail to pass the tests.

Much of the manufacturing process takes place in Klando, Czech Republic and Billund, Denmark. All in all, Lego factories produce 33,000 bricks every minute, for a total of 16 billion bricks every year. The manufacturing facilities can make 3,000 different types of elements, including 300 million tires, and these pieces go into 37,000 Lego sets every hour.

In the next section, we'll look at what you can do with all those finished bricks.­

Building with Lego Bricks

You can make a 2 x 2 brick with three 2 x 2 plates or a 2 x 4 brick with three 2 x 4 plates. Or, you can combine 2 x 2 bricks and plates to make a 2 x 4 brick.
You can make a 2 x 2 brick with three 2 x 2 plates or a 2 x 4 brick with three 2 x 4 plates. Or, you can combine 2 x 2 bricks and plates to make a 2 x 4 brick.
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Basic Lego bricks are full of 90 degree angles, but finished products aren't limited to squares. With enough 90 degree angles close enough together, you can make objects that incorporate spheres and curves. With enough bricks, you can build pretty much anything.

But anyone who has been to a toy store recently knows that Lego pieces are no longer limited to basic bricks. New sets include customized pieces like wings, sails and masts. Some sets, like BIONICLE and KNIGHTS KINGDOM sets, are designed for constructing models that resemble action figures. TECHNIC sets let you turn a Lego creation into a machine by adding studs, axles, motors and gears, and MINDSTORMS sets let you build programmable robots. The FRIENDS line, which drew controversy upon launch, is marketed toward girls and features a beauty salon, a veterinarian's office and a restaurant, among others.

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BIONICLE elements often bear little resemblance to a 2 x 4 brick.
BIONICLE elements often bear little resemblance to a 2 x 4 brick.
Image courtesy ©Lego

So, if you want to build something really impressive, you can buy a kit that includes all the pieces and step-by-step instructions on how to put them together. Or, you can buy lots of bricks in a variety of shapes and sizes, and figure out how to build them yourself. Building from a kit is pretty easy -- the instructions don't even use words, and if you lose your instructions you can download a new set from the Lego site.

Building with LEGO bricks is easy with tools that turn your LEGO bricks into programmable robots and machines.  Learn more about building with LEGO.
Building with LEGO bricks is easy with tools that turn your LEGO bricks into programmable robots and machines. Learn more about building with LEGO.
HowStuffWorks
The Batmobile Dragster starts as several small bags of parts and a set of instructions.
The Batmobile Dragster starts as several small bags of parts and a set of instructions.
HowStuffWorks

In the next section, we'll focus on what it takes to design and build your own creation.

Designing Your Lego Creation

Nathan Sawaya connects two pieces of a large Lego model of the Brooklyn Bridge.
Nathan Sawaya connects two pieces of a large Lego model of the Brooklyn Bridge.
Image courtesy Nathan Sawaya

The first thing you'll need to do is determine exactly what kind of scale you'll be using for your project. This will set the stage for everything from how many bricks you need to how long your project is likely to take. You can make a pocket model, which is basically anything that's small enough to be carried in your pocket. At the other end of the spectrum is sculpture scale, which can be life-size or smaller, but is generally very large. In between is minifig scale, in which you plan the size of your design around the size of the minifigures that will use it. You might also choose to build a two-dimensional mosaic, using a base plate as a foundation.

There's no wrong way to build with Lego bricks, so different people's construction methods can vary greatly. But the first step will generally be research and planning. Here's what certified Lego professional and former Master Builder Nathan Sawaya had to say about planning a project:

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Some people prefer to plan their creations out step by step, or to use computer software to help in their design process. Lego building programs include:

  • Lego Digital Designer, a free program for Windows or Macintosh, which lets you buy exactly the elements you need from the Lego factory
  • LDraw, a brick-based computer-aided design (CAD) program for Windows, Macintosh and Linux
  • Bricksmith, a Macintosh application that uses LDraw's model library

Lego Art

Sawaya connects two large pieces of an 8-foot pencil.
Sawaya connects two large pieces of an 8-foot pencil.
Image courtesy Nathan Sawaya

Ready to create a Lego art sculpture? Once you've got your resource material together and have a sense of where your project is going, all it takes is bricks, time and patience. According to Sawaya:

Lego bricks are tiny compared to sculpture-scale projects. "Large pieces usually involve sketching out ideas, but the true test is being able to picture the finished model in my mind. Since sculpting with Lego is a slow process," Sawaya says, "I have to be able to recognize early on where pieces need to go to develop the shape of the piece as I build upwards. It takes a lot of pieces to get this right, and often I will tear down portions that I have built, so as to rebuild them differently."

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The inside of Sawaya's oversized pencil demonstrates staggering and bracing.
The inside of Sawaya's oversized pencil demonstrates staggering and bracing.
Image courtesy Nathan Sawaya

Builders' construction techniques vary, but most people start at the bottom and work up and out. "The process of sculpting with Lego is usually a bottom-up approach," says Sawaya. "Meaning, I start at the bottom and build my way to the top of the piece. This generally means that balancing issues have already been dealt with by the time I finish a model."

Whether you're building by trial and error or with detailed sketches, there are a few techniques that will help make your final construction sturdy. Staggering bricks, the way builders stagger bricks when building houses, makes wall portions stronger. You can also brace the interior of hollow structures with columns and beams made from additional bricks. A good resource for learning about making your own Lego constructions is Allan Bedford's The Unofficial Lego Builder's Guide. You can also find lots of information on building and creating in the online publication BrickJournal.

We'll look at some of our favorite Lego art sculptures in the next section.

Our Favorite Lego Projects

Nathan Sawaya's Han Solo in carbonite.
Nathan Sawaya's Han Solo in carbonite.
Image courtesy Nathan Sawaya

You can find pictures of amazing Lego creations are all over the Web. Here are some of our favorites:

Sawaya says, "I used over 10,000 individual Lego bricks to build the replica of Han Solo frozen in carbonite. I bought a lot of the bricks directly from Lego.com as part of their bulk sets. A lot of the bricks also came from sets, in which I picked out the pieces I needed. This was one of my first Lego sculptures so I was still learning the best way to amass large quantities of brick. Now, after years as a professional Lego sculptor, I now order hundreds of thousands of bricks in a rainbow of colors from Lego whether I immediately need them or not."

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Philippe "Philo" Hurbain's rolling ball clock, originally created by Bob Kojima.
Philippe "Philo" Hurbain's rolling ball clock, originally created by Bob Kojima.
Image courtesy Philippe "Philo" Hurbain

Hurbain says, "Getting this clock to work reliably for extended time periods was a tough job. Balls tend to get jammed in the input hopper or in the chute. But finally I was able to get good precision with few glitches (just some balls falling from the lift from time to time)."

This printer uses chocolate for ink.
This printer uses chocolate for ink.

More Amazing Lego Sculptures

Andrew Carol's Babbage difference engine.
Andrew Carol's Babbage difference engine.
Image courtesy Andrew Carol

Carol says, "It took me three months to design and construct the machine. It has several thousand parts including over 200 gears. It takes just over 100 turns of the crank for each answer to be computed which gives it a rate of one complete three digit calculation every 45 seconds or so."

The Hammerhead CD launcher, by Philippe "Philo" Hurbain.
The Hammerhead CD launcher, by Philippe "Philo" Hurbain.
Image courtesy Phillip Torrone

Hurbain explains, "I built the CD launcher for a contest published on Lego Mindstorms Forum. I was myself astonished by the power that could be delivered by a few ABS parts and toy motors..."

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Takayuki Muranushi built an automatic book scanner.
Takayuki Muranushi built an automatic book scanner.
Image courtesy Takayuki Muranushi

"The model includes about 500 Lego pieces," Muranushi explains. "It took a whole weekend to build the first model, which was finished Tuesday, February 14, 2006. Lego has camera eyes, sensors and mini-computer bricks, or you can link with a personal computer to do complicated tasks. If you have a dull task, your knowledge of robotics, metal processing and electronics will help. Buying one at store can save your time if they sell what you need. But Lego is another choice. Lego models are very easy to improve. You can recycle one model to another, doing different tasks. Lego models are also "endurable" -- if split into pieces, just put it together again. With Lego you can overcome drudgery of your own, and by your building instruction on the web, a drudgery of the world. And don't forget, Lego-ing is fun! To handle Lego is to play with your ingenuity and exercise it. Sudoku also has such an effect, but Lego is not limited to 9x9 blocks; it's infinite and it helps you in real world tasks."

Minifig-scale Lego Sculptures

The Church of the Flying Spaghetti Monster, by Chris Doyle.
The Church of the Flying Spaghetti Monster, by Chris Doyle.
Image courtesy Chris Doyle

"The Church of the Flying Spaghetti Monster was one of my first ventures into Lego Town-style building," Doyle says. "I went through the same basic starting steps that most builders do -- I doodled a few ideas for the façade and mapped out some rough floor plans. Then I set up a spare card table in my workshop, covered it in base-plates, roughed in the outer wall, and just started adding bricks. Most of my Lego creations take shape in this fairly unstructured manner -- I have a rough idea of what I'm aiming for, but the end result usually surprises me. Construction on the Church took roughly four months in total -- but it was very much a start-and-stop process. I'd finish an area and then have to wait for inspiration to strike before moving on to the next. Actual building time was probably close to 30 hours. Since I built things as I went along I don't have an exact count of the number of elements used, although a fair estimate would be around 3,000 bricks total."

Malle Hawking's minifig-scale aircraft carrier.
Malle Hawking's minifig-scale aircraft carrier.
Image courtesy Pierre/Belgium

Next, we'll look at the history of the Lego brick.

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Lego History

The Lego Center in Billund, Denmark.
The Lego Center in Billund, Denmark.
Image courtesy ©Lego

The Lego Group is now the fourth largest toy manufacturer in the world. It's a privately owned business that employs more than 5,000 people worldwide. About 150 designers of 18 nationalities design and plan the elements for all the different Lego sets. These sets are sold in more than 130 countries.

But the company started as a small family operation. It began in 1932, when Ole Kirk Christiansen started a business in Billund, Denmark. Christiansen made things from wood, including ladders and toys. Christiansen's company continued to make wooden toys until 1960, when its wooden toy warehouse was destroyed in a fire. In 1934, he named the company "Lego," an abbreviation of the Danish words "leg godt," or "play well."

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Lego started making plastic toys in 1947, and it was the first company in Denmark to use a plastic injection-molding machine. By 1951, plastic toys made up half of the company's output. The company refined their designs between 1949 and 1958, but since 1958, the basic bricks have remained unchanged.

The Lego Group began adding additional elements to the basic bricks in the 1960s and 1970s. Lego figures, which originally had a yellow skin tone and were neither male nor female, arrived on the scene in 1974. The mechanical elements known as Lego TECHNIC hit the market in 1977, and MINDSTORMS robots products made their debut in 1998. The MINDSTORMS line was the product of a collaboration between the Lego Group and the Massachusetts Institute of Technology Media Lab.

Lego MINDSTORMS NXT
Lego MINDSTORMS NXT
Image courtesy ©Lego

The newly-released Lego MINDSTORMS NXT set includes the "intelligent brick," which contains a microprocessor, as well as three motors, four sensors, programming software and 571 TECHNIC elements. A group of users -- the MINDSTORMS User Panel -- helped the Lego Group create the new system.

The Lego Group Today

Image courtesy ©Lego
Image courtesy ©Lego
Image courtesy ©Lego

A commonly-cited statistic is that there are 102,981,500 possible combinations of 6-sided, 8-stud bricks. But that number only works if the final product is a tower that's six bricks tall. A computer program has helped reveal a more accurate number -- there are 915,103,765 possible 6-brick combinations.

Although Lego has introduced several theme sets over the years, including House, Farm and Pirates, the company didn't create any licensed products until 1999. That's when Lego introduced "Star Wars" and "Winnie-the-Pooh" sets. But the decision to make licensed products wasn't an easy one for the company. Producing a set of elements that had a set purpose rather than being open-ended was completely contrary to the philosophy of open-ended building play. However, the "Star Wars sets quickly became the best-selling new product line in company history. The company's philosophy now is that these sets add storytelling to building play.

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The current Lego product lines include licensed sets that portray characters and scenes from "Star Wars," D.C. Comics (including Batman), "Bob the Builder," "Thomas the Tank Engine" and Nick Jr. television shows like "Spongebob Squarepants." There are also numerous themed sets on the market as well as larger QUATRO and DUPLO bricks for infants and toddlers. But in spite of the popularity of all these product lines, the last few years haven't been easy for the Lego Group.

A castle in the Deutschland, Germany LegoLAND Park, now owned by Merlin Entertainments Group.
A castle in the Deutschland, Germany LegoLAND Park, now owned by Merlin Entertainments Group.
Image courtesy ©Lego

The Lego Group's profits peaked in the mid-1990s. In 1998, the company reported a pre-tax loss. It had its first large-scale layoff in 1999, and in 2000 it lost about a billion Danish Kroner (about $120 million). Most analysts theorize that the new prevalence of electronic devices marketed to children, like MP3 players and video game systems, has caused part of the drop in sales. In addition, the Lego Group's major patents have expired, so competitors like Mega Bloks have been able to produce less-expensive sets that are compatible with Lego bricks. The introduction of the Friends line gave the company a significant boost in sales, but it came with a hefty dose of criticism that the sets reinforced sexist stereotypes.

To try to streamline the company, the Lego Group decided to re-focus its efforts on becoming profitable, and it sold some of its businesses, including the sale of LegoLAND Parks to Merlin Entertainments Group in 1995. The company also moved much of its more labor-intensive manufacturing processes to Klando, Czech Republic, to reduce costs. After its restructuring and sale of businesses, the Lego Group reported a profit again in 2005.

Check out the links on the next page for lots more information about Lego construction and related topics.

Related Articles

More Great Links

Sources

  • Austen, Ian. "Building a Legal Case, Block by Block." New York Times, February 2, 2005.
  • "China Reins as the World's Toy Maker." Plastics News, December 19, 2005.
  • Fishman, Charles. "Why Can't Lego Click?" Fast Company. September 2001. http://www.fastcompany.com/magazine/50/lego.html
  • Knudsen, Jonathan. "Lego Mindstorms: Lego and MIT." O'Reilly Network. 1/31/2000. http://www.oreillynet.com/pub/a/network/2000/01/31/mindstorms/index1b.html
  • "How Lego Bricks are Made." Lego. http://www.lego.com/eng/info/default.asp?page=bricks
  • "Lego Design School." Lego. http://www.lego.com/eng/create/designschool/lesson.asp?id=1_a
  • Martin, Fred G. "The Art of Lego Design." March 15, 1995.
  • Terdiman, Daniel. "Hacking's a Snap in Legoland." Cnet, September 15, 2005. http://news.com.com/Hackings+a+snap+in+Legoland/2100-1046_3-5865751.html?tag=nefd.top
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  • Lego Play Materials and the Environment. The Lego Group.