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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 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 than 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.
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.
The 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 ambitious 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 off 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.
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 sensitive or complex for machines, while machines do 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.
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.
Cars changed the way people lived, worked, and enjoyed leisure time; however, what most people don’t realize is that the process of manufacturing automobiles had an equally significant impact on the industry. The creation of the assembly line by Henry Ford at his Highland Park plant, introduced on December 1, 1913, revolutionized the automobile industry and the concept of manufacturing worldwide.
Henry Ford was not a newcomer to the business of automobile manufacturing. He built his first car, which he christened the “Quadricycle,” in 1896. In 1903, he officially opened the Ford Motor Company and five years later released the first Model T.
Although the Model T was the ninth automobile model Ford created, it would be the first model which would achieve wide popularity. Even today, the Model T remains an icon for the still-existing Ford Motor Company.
Henry Ford had a goal of making automobiles for the multitudes. The Model T was his answer to that dream; he wanted them to be both sturdy and cheap. In an effort to make Model T’s cheaply at first, Ford cut out extravagances and options. Buyers couldn’t even choose a paint color; they were all black. By the end of production, however, the cars would be available in a wide variety of colors and with a wide variety of custom bodies.
The cost of the first Model T was set at $850, which would be approximately $21,000 in today’s currency. That was cheap, but still not cheap enough for the masses. Ford needed to find a way to cut down the price even further.
In 1910, with the aim of increasing manufacturing capacity for the Model T, Ford built a new plant in Highland Park, Michigan. He created a building that would be easily expanded as new methods of production were incorporated.
Ford consulted with Frederick Taylor, creator of scientific management, to examine the most efficient modes of production. Ford had previously observed the assembly line concept in slaughterhouses in the Midwest and was also inspired by the conveyor belt system that was common in many grain warehouses in that region. He wished to incorporate these ideas into the information Taylor suggested to implement a new system in his own factory.
One of the first innovations in production that Ford implemented was the installation of gravity slides that facilitated the movement of parts from one work area to the next. Within the next three years, additional innovative techniques were incorporated and, on December 1, 1913, the first large-scale assembly line was officially in working order.
The moving assembly line appeared to the onlooker to be an endless contraption of chains and links that allowed Model T parts to swim through the sea of the assembly process. In total, the manufacturing of the car could be broken down into 84 steps. The key to the process, however, was having interchangeable parts.
Unlike other cars of the time, every Model T produced on Ford's line used the exact same valves, gas tanks, tires, etc. so that they could be assembled in a speedy and organized fashion. Parts were created in mass quantities and then brought directly to the workers who were trained to work at that specific assembly station.
The chassis of the car was pulled down the 150-foot line by a chain conveyor and then 140 workers applied their assigned parts to the chassis. Other workers brought additional parts to the assemblers to keep them stocked; this reduced the amount of time workers spent away from their stations to retrieve parts. The assembly line significantly decreased the assembly time per vehicle and increased the profit margin.
As time passed, Ford used assembly lines more flexibly than he is generally given credit for. He used multiple parallel lines in a start-stop mode to adjust output to large demand fluctuations. He also used sub-systems which optimized extraction, transportation, production, assembly, distribution, and sales supply chain systems.
Perhaps his most useful and neglected innovation was the development of a way to mechanize production and yet customize the configuration of each Model T as it rolled off the block. Model T production had a core platform, a chassis consisting of engine, pedals, switches, suspensions, wheels, transmission, gas tank, steering wheel, lights, etc. This platform was continually being improved. But the body of the car could be any one of several types of vehicles: auto, truck, racer, woody wagon, snowmobile, milk wagon, police wagon, ambulance, etc. At peak, there were eleven basic model bodies, with 5,000 custom gadgets that were manufactured by external companies that could be selected by the customers.
The immediate impact of the assembly line was revolutionary. The use of interchangeable parts allowed for continuous workflow and more time on task by laborers. Worker specialization resulted in less waste and a higher quality of the end product.
Sheer production of the Model T dramatically increased. The production time for a single car dropped from over 12 hours to just 93 minutes due to the introduction of the assembly line. Ford’s 1914 production rate of 308,162 eclipsed the number of cars produced by all other automobile manufacturers combined.
These concepts allowed Ford to increase his profit margin and lower the cost of the vehicle to consumers. The cost of the Model T would eventually drop to $260 in 1924, the equivalent of approximately $3,500 today.
The assembly line also drastically altered the lives of those in Ford’s employ. The workday was cut from nine hours to eight hours so that the concept of the three-shift workday could be implemented with greater ease. Although hours were cut, workers did not suffer from lower wages; instead, Ford nearly doubled the existing industry-standard wage and began paying his workers $5 a day.
Ford’s gamble paid off—his workers soon used some of their pay increases to purchase their own Model Ts. By the end of the decade, the Model T had truly become the automobile for the masses that Ford had envisioned.
The assembly line is the primary mode of manufacturing in the industry today. Automobiles, food, toys, furniture, and many more items pass down assembly lines worldwide before landing in our homes and on our tables.
While the average consumer does not think of this fact often, this 100-year-old innovation by a car manufacturer in Michigan changed the way we live and work forever.