The assembly line is one of the great achievements in modern manufacturing. 

Since the industrial revolution, assembly lines have allowed manufacturers to make goods at an unprecedented pace and scale.

In the last 10 years, however, the assembly line itself has undergone something of a revolution. With new digital technologies now commonplace in factories, the assembly line has had to adapt. 

This post will give a quick history of the assembly line, and describe how new technologies are transforming one of the 

What is an assembly line?

Assembly lines are manufacturing systems in which work-in-progress moves from station to station in a sequential fashion. At each workstation, new parts are added or new assemblies take place, resulting in a finished product at the end. 

Assembly lines areAssembly lines are manufacturing systems in which work-in-progress moves from station to station in a sequential fashion.

Assembly expedited the entire manufacturing process by conveying semi-finished products from process to process. This was a massive improvement to previous methods, in which complex production routing and disconnected processes added complexity to assemblies. 

Further, assembly lines enabled workers to develop process-specific expertise that helped full lines work more efficiently. 

As a result, manufacturers could finish complex products like cars, aircraft, and industrial machines at a greater rate with more precision than ever before. 

A short history of the assembly line

So how did we get here? Here’s a quick history of the assembly line. 

Manufacturing before the Assembly Line

While some form of assembly lines have existed for thousands of years, it was only in the last 100 that they became a mainstay in factories. 

It helps to understand how manufacturing processes were designed before the assembly line.

Prior to the Industrial Revolution, objects were often manufactured from end-to-end by single artisans. If a given assembly required 20 parts and 30 steps to manufacture, a single individual would work through the assembly in order, until they produced a finished product. 

How did assembly lines make mass production possible?

With the industrial revolution, manufacturers began to place operators on specialized tasks.

So rather complete a single object, they would specialize in a single process–for example, cutting, lathing, or a particular manual assembly. 

By the early 20th century, all of the parts were in place for the modern assembly line to emerge. 

With the advent of interchangeable parts, electric conveyor belts, and new types of machining processes, assembly lines were poised to make the world. 

Henry Ford and the Automotive Assembly Line

The automotive plant is the first thing many people think of when they hear “assembly line.” Henry Ford of Ford Motor Company is often credited with inventing the assembly line. 

There’s some dispute, however, as to whether or not Henry Ford invented the automotive assembly line. 

Early automotive assembly line to illustrate how Ford and others built early cars.
An Early Automotive Assembly Line-

In reality, many manufacturers were experimenting with assembly line systems in the 20th century. Indeed, Ransom Olds–an early innovator in the automotive industry–is credited with inventing the first automotive assembly line system. 

Consensus among historians seems to be that while Ford Wasn’t first, he did do more to advance the assembly line than his contemporaries. Ford set ambitions production goals, set faster production rates than his peers, and made a science of assembly line design and line balancing.

On Ford’s assembly lines, an empty chassis became a complete car in a matter of hours, not days.  

This precedent was quickly imitated and improved by competitors, leading to a rapid evolution in manufacturing processes. 

By mid-century, millions of cars rolled of Ford assembly lines, paving the way for America’s auto-first transportation culture. 

Assembly Lines Spread to Other Industries

Soon, the optimized assembly spread to other industries. 

By mid-century, assembly lines were present in industries beyond discrete manufacturing, including chemicals, oil, and other continuous manufacturing industries. 

At present, the assembly line–or at least a more sophisticated iteration of it–is a fixture in manufacturing across industries and product specializations. 

Evolution of the assembly line with automation

While assembly lines made some manufacturing processes significantly more efficient, some manufacturers looked for new ways to improve accuracy and lower costs. 

By mid-century, assembly lines were in use in many manufacturing industries across the world.

Thus, as various forms of automation matured over the course of the 20th century, manufacturers incorporated them into their processes. Gradually, automated tools began to take over simple, repetitive tasks. Over time, the amount of automation on assembly lines increased significantly.

While there are examples of fully automated assembly lines, most assembly lines are mixes of humans and automated labor. Humans perform the assemblies and tasks that are too senstitive or complex for machines, while machines to the work that’s too repetitive, dangerous, or error-prone for humans. 

The Legacy of the Assembly Line

So what did the assembly line make possible?

  • Mass production
  • Safer working conditions 
  • Automobiles priced for the consumer market
  • Bolstered the United State’s position as an economic power
  • Higher wages for workers for much of the 20th Century

Future of the assembly line

Just as the invention of steam power instigated an industrial revolution in the 18th century, digital technologies are sparking a new industrial revolution today. 

While it’s tempting to imagine the future of the assembly line as a fully automated endeavor, the reality is a little more complex. 

The biggest advances in assembly line production will come less from automation and more from increased visibility into industrial processes. 

Indeed, modern assembly lines are close collaborations between humans and machines, coordinated by applications not unlike those you find on your smartphone. 

Modern assembly lines are filled with digital and industry 4.0 technology.
A modern assembly line with digital technology

With IIoT, big data, computer vision, and other Industry 4.0 technologies, assembly lines continue to feature some of the most advanced technology on the planet. 

Features of the Modern Assembly Line

Here are some ways that the modern assembly line differs from Ford’s. 

Data Collection

In the modern assembly line, new kinds of sensors and IIoT devices collect data from humans and machines in real time.

Collaborative

Thanks to advanced robotics, collaborative automation, and more sophisticated software, humans work more intimately with machines on assembly lines than ever before.

Less Linear

Some assembly lines are less linear than their predecessors. Instead, work is routed dynamically between different lines and cells as necessary.

High-Mix Products

With high demand for customization and more advanced error-proofing technology, modern assembly lines can produce hundreds of variants of a single product.