How LEGO®️️ Uses Precision Molding To Make Their Toys

LEGO® is one of the most easily recognizable and highly esteemed brands globally. Its distinctive design of interlocking plastic bricks has captivated children and adults as it helps unlock their inner creativity while offering endless possibilities. 

One key factor contributing to the LEGO® brand’s success is its reputation for quality and durability. LEGO® bricks are renowned for their sturdiness, capable of supporting the weight of 375,000 other bricks before failing – a testament to their incredible design.

At the core of LEGO®’s success lies precision molding, which plays a crucial role in maintaining the highest standards that ensure the quality and fit of each brick. This commitment to excellence has solidified LEGO®’s position as a leader in the industry.

What plastic are LEGOs made of, and how are they made? This blog will explore how LEGO® is made and how precision molding produces these injection-molded toys.


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.


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 LEGO® is Made


What types of plastic are LEGOs manufactured with? 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. The general manufacturing process for these products involves the following steps:


Granule Delivery and Transport


  1. The production process begins with the arrival of plastic granules at the LEGO® factory. These granules serve as the raw materials used to produce their toy bricks and other products. 
  2. The granules are unloaded from the trucks and stored in large, three-story-high metal silos. Each of these silos is capable of holding up to 33 tons of granules. Meanwhile, LEGO factories will typically have 14 silos inside the facility.
  3. The plastic granules are then transported from the silos through pipes to a LEGO molding machine to undergo the plastic injection molding process.


The Plastic Injection Molding Process


  1. In the early stages of plastic injection molding, plastic granules are heated to approximately 450 °F (230 °C). The extreme heat melts down the plastic granules to prepare for molding.
  2. The molten plastic is injected into molds, which are metal containers that like hollow LEGO bricks. Within these molds, substantial pressure is applied to ensure the molten plastic fills all the cavities and conforms to the shape of the mold.


*The entire injection molding process is automated to increase the production speed and capacity while maintaining accuracy and precision. 


Ejection and Conveying


  1. Once formed, the bricks are rapidly cooled until they have solidified and are ejected from the molds.
  2. All ejected LEGO pieces are transported on conveyor belts to various collection points throughout the facility. Robot trucks navigate the factory floor to pick up the finished pieces and place them onto another conveyor belt to advance them to the next manufacturing stage.
  3. Various details and decorations are added to the LEGO pieces inside assembly halls. These include control panels, faces, words, numbers, and other decorative elements printed onto the bricks by giant printers. 


Part Assembly and Packaging


The final step involves assembling all the necessary pieces to create complete LEGO sets. Since LEGO toy sets contain hundreds of components, the packaging process must be fast and accurate. 


  1. Boxes called cassettes move along conveyor belts beneath bins that store each type of LEGO piece. These bins open and close to release the correct number of parts into each cassette. 
  2. Packaging operators fold the boxes, insert building instructions, and add any additional pieces required for the set. They also inspect for any machine-made mistakes before the sets are sealed and prepared for distribution.


Interesting Facts About LEGO® and Plastic Injection Molding


  • Plastic injection molding plays a crucial role in maintaining the strict quality standards of LEGO® blocks. Since they were invented, the sizes of their blocks maintain tolerances of 0.0005 inches to ensure uniformity across all pieces.
  • LEGOs can withstand compression forces up to 950 lbs – higher than that of concrete. Its incredible durability is made possible by using high-grade polymers during manufacturing and its small cellular architecture. 
  • Due to the intricate design and level of accuracy needed, each LEGO plastic injection mold can cost up to $200,000, with some going as high as $360,000. According to some news reports, the LEGO factory keeps as many as 7,000 molds within their facility.


Elevate Your Toy-Making Capabilities With All-Plastics


Plastic injection molding enhances your manufacturing capabilities with the ability to mass-produce intricate plastic components and complex products. It offers greater flexibility while ensuring efficiency in meeting market demand. By utilizing plastic injection molding, businesses like yours can reduce production costs, increase productivity, and ultimately thrive in today’s competitive market.

All-Plastics offers plastic injection molding solutions that help you reach your production goals. Whether you’re developing toys or plastic products with complex configurations, we deliver everything you need to optimize your manufacturing processes and achieve outstanding results. Please complete our online contact form to request a quote or more information about our services.