Mixed-Model Assembly

What is Mixed-Model Assembly?

Mixed-Model Assembly is a type of production system that produces several distinct products or models within one operation without decreasing productivity, efficiency, and quality. Within these environments, the number of products built on one line can reach up to hundreds of thousands of variations.

The frequency and specifications of the models produced are highly dependent on the specific demand for each product. Because of this, certain products could be frequent flyers on the production line while others will only populate every 6 months to a year. In some cases, as with one-off productions, a model may only be assembled once. Then the line is changed over to a new assembly job.

In contrast to this system, a mass production assembly line focuses on only one or two products. The assembly line produces products in an environment where all actions, equipment, and materials are standardized into one continuous flow.

The hot topic for many mixed-model manufacturers is “how can we maintain the strengths of standardization within a mixed-model assembly line?”.

Why is Mixed-Model Assembly a Thing?

Well, this is a bit complicated and requires a look at the history of manufacturing.

You may be familiar with the moving assembly line of the 2nd Industrial Revolution. One product, such as the Ford Model T, traveled down the moving assembly line while stationary workers repeated the same actions over and over. This created a standardized method that would be used and improved over the next century and beyond.

This was revolutionary but there was a problem. Customers could only get the Ford Model T with absolutely zero variation. Even the exterior color was limited to only black.

But as technology and processes evolved over the century, customers have progressively demanded more variation from their products while also placing less importance on the life cycle of the products they buy. And with the introduction of e-commerce, where online stores such as Amazon have access to close to 3,000 times as many products as any big box store, the market has grown accustomed to massive product variation, customization, and choice. This has led to a new manufacturing environment that is always moving, one that requires flexibility.

Just think about the last time you bought a kid's toy. It’s no longer the one red truck that pervades the entire top three shelves. Its red trucks, blue cars, and yellow SUVs, all accessible online from thousands of brands. And most of these toys come from brands and manufacturers that also made variations of dolls, playhouses, BBQs, patio furniture, industrial shelving units, and more.

Additionally, companies are more likely to add products to their line of offerings while being less likely to remove some of the older ones, creating a wider range of options for customers.

While mass production is still vital for some products and brands, the mixed-model assembly line is vital to the growing trends of the future connected global market.

The Top 3 Pros and Cons of Mixed-Model Assembly

The mixed-model assembly line has its key benefits while also introducing some key challenges. Each challenge comes with a key benefit and vice versa. So whether this production system is best for you will highly depend on your product, your intended market, and your business goals and strategies.

With this in mind, here are the top 2 Pros and Cons of the mixed-model assembly line and some ways to boost the benefits and mitigate the challenges.

The Top 2 Pros

1. Meet various revenue streams
2. Less expensive and more efficient inventory

Let’s unpack these a bit.

The main benefit of mixed-model assembly is the ability to interact with flexibility. Companies that can quickly change their production lines to meet the needs of their customers and new revenue streams are better able to face new challenges and take hold of new opportunities.

Have you heard of “not putting all your eggs in one basket”? Mixed-model assembly is exactly that.

From an inventory perspective, the mixed-model assembly line also enables manufacturers to hold less inventory by using a pull manufacturing system where demand sets the pace of production. Since customer demand dictates the configuration, pace, and amount of products assembled, mixed-model manufacturing companies can decrease their inventories to mere fractions of what they used to be.

The Top 2 Cons

1. Requires greater management and strategy
2. Potentially confusing for workers

One of the main drawbacks to mixed-model assembly is that it is difficult to manage. Pretty much every benefit of mixed-model assembly comes with a layer of added complexity, resulting in an operation that can be difficult to manage.

With diverse processes comes diverse challenges.

Adding to this, workers can become confused with their specific tasks.

Let's go back to the moving assembly line of the 2nd industrial revolution. Every worker had one task that they would repeat for their entire shift. Although super boring and monotonous, there is very little space for confusion. In contrast, mixed-model assembly workers have different tasks almost every day. And certain tasks are so infrequent that it makes it strenuous for workers to remember how to perform the jobs to a sufficient degree.

However, there are ways to streamline management and give your workers the right process knowledge.

How To Solve Mix-Model Assembly Challenges

Despite the diverse challenges of mixed-model assembly, companies can eliminate these issues through intelligent standardization with tools like work instruction software.

Now, standardization may seem to be in contrast to all that we’ve said about mixed-model assembly but this is not the case. It just looks different.

Instead of standardizing one person’s job as we did over 100 years ago, we can now standardize every process through a digital and interactive platform. The process, along with best practices, quality control, safety standards, and company knowledge are recorded in visual guidebooks that employees can access when performing any job.

This method of Industry 5.0 standardization gives every worker the confidence to perform their tasks in the most efficient manner. And with workers always following the established best practices, line changeovers are made faster and more efficiently, enabling mixed-model assembly lines to experience continuous flow.