Brick Sorting Robot: From LEGO Piles to ABB Robot Arms

Anyone who owns a bucket of LEGO knows the sorting problem: thousands of small parts, hundreds of shapes and dozens of colors in one heap. A brick sorting robot tries to solve that. It is a good test case: the parts are small, the variety is huge and each piece is worth little. This autumn a Lancashire company showed how far the idea has come. This post follows the brick from its first plastic version to the AI sorting line in the news, and to the robots that build with bricks. It also looks at where ABB robots such as the IRB 360 FlexPicker and the YuMi fit.

A heap of mixed LEGO bricks, the sorting problem in one photo. Photo: Alan Chia / Wikimedia Commons (CC BY-SA 2.0)

How the LEGO brick was made and how people sorted it

The company began with a carpenter, Ole Kirk Christiansen of Billund, Denmark, who started making wooden toys in 1932. In 1934 he named it Lego, from the Danish phrase "leg godt", meaning "play well". Plastic arrived later. In 1949 the firm began producing an interlocking brick called Automatic Binding Bricks, based on the Self-Locking Bricks that Hilary Page had invented in 1939. A patent application for the modern brick design was filed in Denmark on 28 January 1958.

The first patented LEGO bricks from 1958, on display at Danmarks Tekniske Museum in Helsingor. Photo: Leif Jorgensen / Wikimedia Commons (CC BY-SA 4.0)

The 1958 design depends on one thing: the bricks have to fit together every time. That takes accurate molds. Lego allows its molds a tolerance of up to 20 micrometres, and the machines that make the bricks work to tolerances as small as 10 micrometres, or 0.01 mm. Production now averages about 36 billion bricks a year, roughly 1,140 elements every second. At that volume nobody sorts by hand, so the factory side runs on machines.

A humanoid robot built from a LEGO Mindstorms NXT kit. Photo: Marlon J. Manrique / Wikimedia Commons (CC BY 2.0)

At home, sorting stayed manual for decades. Collectors tipped out a box, picked pieces by color and shape, and filled labeled drawers. The first robots to meet the brick arrived as toys. Lego's Mindstorms robotics line launched in 1999 and ran until it was discontinued in 2022, and its programmable brick originated at the MIT Media Lab. Students and hobbyists built their first robots from bricks, including sorting robots that used a color sensor to push bricks into bins.

Arburg injection molding machines on a factory floor, the kind used to mold plastic bricks. Photo: FFA P-16 / Wikimedia Commons (CC BY-SA 4.0)

What a brick sorting robot looks like in 2026

The news this autumn comes from Rawtenstall in Lancashire, where WeBuyBricks runs a machine called the Brick-O-Matic. The BBC reported on 17 September that the AI machine helps save 25 million bricks from landfill, a figure that comes from the company. It uses cameras, conveyor belts, air jets and AI to recognise single pieces from more than 55,000 possibilities, then sorts them by shape and color. It can sort about 40,000 pieces a day, and the company spent four years developing it. It calls the machine the first commercially viable one of its kind in the UK and one of only three in the world.

A small pile of colorful LEGO bricks, the raw material for a sorting line. Photo: GTurnbull925 / Wikimedia Commons (CC BY-SA 4.0)

The machine does more than separate colors. It can work out which set a pile of bricks came from and report how complete the set is, so incomplete sets can be rebuilt and resold. Bricks are washed along the way, and damaged pieces are removed. The company says doing the same job by hand would take people about 100 times longer. Press coverage describes the cameras and air jets but not the inside of the software, so I cannot say how it picks parts. A hobbyist built something similar in 2019 out of about 10,000 LEGO bricks.

ABB IRB 360 FlexPicker delta robots picking items on a moving line. Photo: ABB

ABB robots do the same kind of picking and assembly work in industry. The IRB 360 FlexPicker is a delta robot that picks items from a moving conveyor at high speed using vision, which is the core skill of a sorting line. The dual arm YuMi IRB 14000 is made for small parts assembly and works near people, while the IRB 930 SCARA arm, launched in 2023, handles electronics and battery assembly. No source I found says ABB robots sort LEGO today, so this is a fit and not a project. Such cells are normally planned first in RobotStudio.

ABB's dual arm YuMi IRB 14000, made for small parts assembly, here working beside a lab technician. Photo: ABB

Where brick robots go next

For homes, the goal is a tidy bin of bricks without the sorting. A machine for the kitchen table would need to handle dust, sticky fingers, mixed sets and parts from other brands, and it would need to be cheap enough to compete with a free Saturday. The open problems are cost, size and noise, and whether a family would trade a sorted collection for the fun of sorting it. Sort A Brick launched an AI powered LEGO sorting system in October 2025, according to Tech.eu, so the technology is no longer limited to one warehouse. A school kit like Mindstorms shows the other direction, where the robot is built from bricks and the child learns the control side.

The parts of a LEGO Mindstorms NXT kit laid out in its tray. Photo: Marlon J. Manrique / Wikimedia Commons (CC BY 2.0)

For factories, the hard part is variety. Used bricks arrive scratched, faded, dirty and mixed with other toys, and a vision system has to cope with every case. The Brick-O-Matic blows parts into bins with air jets, so a gripper is not always needed. Handling many different small parts is also what a good gripper and a vision guided arm are built for, and our post on recycling sorting robots shows ABB FlexPicker lines picking from a moving stream. The reuse side is growing too, since sorted sets can be sold again instead of being thrown away.

An engineer with an ABB IRB 930 SCARA robot, launched in 2023 for electronics and battery assembly. Photo: ABB

New bricks are still being made in large numbers. A headline from 24 September says the LEGO Group is investing more than $400 million in its Mexico factory, which suggests more molding and more handling work around the machines. Our post on toy manufacturing robots covers that side. The open problems for any brick robot are cost, safety around moving arms, and a supply of people who can program and maintain the cells.

A bin of light gray LEGO bricks at a LEGO store. Photo: Grendelkhan / Wikimedia Commons (CC BY-SA 4.0)

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