Lean Manufacturing: What It Is and the Seven Wastes

In a dream world, every manufacturer would have the simplest yet most effective processes in place to make their supply chain as efficient and revenue driven as possible. This is the basis of Lean Manufacturing. Eliminate anything within your supply chain that is not driving revenue or adding value.

In this blog post, we will discuss what exactly Lean Manufacturing is, and the main "wastes" that contribute to an inefficient supply chain.

What is Lean Manufacturing?

The main idea behind lean manufacturing is fairly simple: continuously work on eliminating waste from the manufacturing process. A modern approach to supply chain management can help organizations identify and address these inefficiencies.

So, what is waste? Waste is any activity or process that isn't bringing added value to your customer. The types of waste vary depending on what industry you are working with, however, every field of work produces some form of waste.

Seven Types of Waste

Let's dive a little deeper into the waste category now. Lean identifies seven key areas of waste, typically referred to as the Seven Deadly Wastes:

Transport
Inventory
Motion
Waiting
Overproduction
Over-processing
Defects

Transport

Transport is the movement of materials from one location to another, this is considered a waste as it adds zero value to the product. You are paying someone to move materials, a process that only costs you money and makes nothing for you. Obviously, transportation is necessary for the manufacturing of any product, but it is the unnecessary movement of raw materials, work-in-process or finished goods that we need to focus on.

There are a few ways to improve this process and avoid unnecessary transport, starting with route optimization strategies. Map out a linear, sequential flow from raw materials to finished goods, keeping in mind continuous flow. You want to make sure that work-in-process is not placed into inventory, but rather it flows smoothly through production without barriers.

Inventory

Inventory does nothing but cost you money. Whether this is a raw material, work-in-progress or finished good, it has a cost to you until it is actually sold. Inventory also feeds other types of waste. All inventory at one time or another has to be stored, requires space, needs packaging or has to be transported. It also has the risk of being damaged, resulting in a complete loss. Again, inventory is unavoidable, they key here is to only have in your possession the quantities necessary for the immediate need.

This is another area where having that mapped out, continuous flow is important. It also fully supports just-in-time manufacturing which greatly reduces inventory waste. This is where parts are pulled through production based on customer demand instead of projected demand.

Motion

Unnecessary motions are movements of people that are not as small or as easy to achieve as could be possible. For example, if you staff member is bending down to floor level to retrieve heavy objects rather than the objects being fed to that person at waist level reducing stress and time. This can also include excessive travel between work stations.

To avoid motion waste, it's best to apply the Six Sigma 5S philosophy:

Sort – eliminate what isn't needed
Set in Order – organize the remaining items
Shine – clean and inspect work area
Standardize – write standards for the previous S's
Sustain – continuously apply the standards

We'll get into this philosophy in more detail in the next blog post.

Waiting

How often are you stuck waiting for an answer from another department, or waiting on a shipment from a supplier? It can be extremely eye-opening to look at the timeline from order to shipment and see how much of that time is spent on actual value-added manufacturing. This waste of waiting disrupts the flow of your manufacturing process, which is one of the main principles of lean manufacturing and is considered one of the most serious wastes.

To decrease (and hopefully eliminate) waiting waste, you need to take a long, hard look at your manufacturing timeline and flow. Then, design a process so that the flow is continuous and there are minimal disruptions between steps in production. Use standardized work instructions, so that consistent methods and times are used for each step in your process.

FAQs

What is lean manufacturing in simple terms?

Lean manufacturing is the practice of continuously eliminating waste from the production process so only work that adds customer value remains. In lean thinking, waste is any activity that does not create value for the customer. The goal is a more efficient, revenue-driven supply chain with fewer delays, less excess, and smoother flow from raw materials to finished goods.

What are the seven types of waste in lean manufacturing?

The seven types of waste in lean manufacturing are transport, inventory, motion, waiting, overproduction, over-processing, and defects. These are often called the Seven Deadly Wastes. Each one represents activity that consumes time, space, labor, or money without adding value to the finished product or the customer experience.

Why is inventory considered waste in lean manufacturing?

Inventory is considered waste because it costs money before it is sold and can create more waste through storage, packaging, transport, and damage risk. Lean manufacturing aims to keep only the quantities needed for the immediate need. Continuous flow and just-in-time manufacturing help reduce excess inventory by pulling parts through production based on customer demand.

How can manufacturers reduce transport waste?

Manufacturers can reduce transport waste by removing unnecessary movement of raw materials, work-in-process, and finished goods. A linear, sequential flow from raw materials to finished goods helps, along with route optimization and a process design that keeps work moving continuously instead of sitting in inventory between steps.

What causes waiting waste in lean manufacturing?

Waiting waste happens when people, materials, or information sit idle instead of moving through production. Common examples include waiting for another department, waiting on a supplier shipment, or having long gaps between process steps. It is one of the most serious wastes because it disrupts continuous flow and reduces the time spent on actual value-added work.

How do 5S principles help reduce motion waste?

The 5S philosophy helps reduce motion waste by making work areas easier and safer to navigate. Sort removes what is not needed, Set in Order organizes remaining items, Shine keeps the area clean and inspected, Standardize documents the first three steps, and Sustain keeps the system in place. The result is less unnecessary movement and less wasted time.

Why is continuous flow important in lean manufacturing?

Continuous flow is important because it reduces interruptions between production steps and helps eliminate several kinds of waste at once. When materials move smoothly through the process, there is less waiting, less inventory buildup, and less unnecessary transport. It also makes it easier to match production to customer demand instead of projected demand.