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TIMWOOD: The Seven Wastes of Lean Manufacturing

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I am a trainer and consultant in lean manufacturing, Six Sigma, quality management, and business management.

"TIMWOOD" is a way to remember the seven wastes to reduce and eliminate in manufacturing.

"TIMWOOD" is a way to remember the seven wastes to reduce and eliminate in manufacturing.

Who or What is TIMWOOD?

Running an efficient business involves lean manufacturing, a waste-reducing method that affects production plans, manufacturing, and customer relations. Using the mnemonic "TIMWOOD" can help you reduce costs, increase profits, improve lead times, and boost customer satisfaction. The easiest way to remember the seven wastes is to ask yourself, "Who is TIMWOOD?".

"TIMWOOD" stands for:

  • Transport
  • Inventory
  • Motion
  • Waiting
  • Over-processing
  • Overproduction
  • Defects

If you can identify existing wastes, you can work to reduce or hopefully eliminate them. However, make sure not to focus solely on eliminating the seven wastes. If you implement lean principles, waste will inevitably be reduced or eliminated.

Transportation is one of the seven wastes identified in "TIMWOOD."

Transportation is one of the seven wastes identified in "TIMWOOD."


The waste of transportation refers to the movement of products in between processes. This typically involves using a forklift truck or smaller similar equipment to maneuver products around the factory. The situation is typically caused by overproduction and inefficient building layouts.

Factories are normally laid out in a traditional style where specific processes are located in different areas. For instance, all the molding is done in one area, and all the machining is done in another. This creates the need to transport a product over potentially long, unnecessary distances.

How to address transportation issues

  • Placing processes as close together as possible, with the material moving directly from process to process without significant delays
  • Improving the production pathway
  • Having multiple storage locations
  • Not creating lengthy or complex material-handling systems

Transportation wastes time and energy and can end up damaging the products themselves. I once worked on a missile factory project where the missiles moved a greater distance in production around the factory than they traveled when fired!

Inventory is another problem to reduce or eliminate in lean manufacturing.

Inventory is another problem to reduce or eliminate in lean manufacturing.


Inventory includes products in production and completed stock that sit around, take up space, and cost you money. One of the principles of lean manufacturing is "just in time," which involves producing what customers want, only when they want it. Failure to follow these principles results in overproduction and accumulated inventory.

Inventory is created by the waste of overproduction and is the worst of all the seven wastes. If you see unnecessary product lying around, it's an indication that the production process doesn't have a continuous flow.

How to prevent having excess inventory

  • Adjust the production process to create a smooth flow of labor
  • Work with smaller batch sizes
  • Observe the first-in-first-out principle regarding stagnant materials
  • Reduce the changeover time
  • Ensure workers adhere to procedures

Many problems hide under the "sea" of inventory. We end up putting up with unreliable machinery and suppliers because the consequences are disguised by the amount of inventory we have to work with.

Motion is one of the seven wastes in "TIMWOOD."

Motion is one of the seven wastes in "TIMWOOD."

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The waste of motion refers to the movement within a process rather than the movement of material between processes (transportation). You can see this when you watch someone at work and see how often they have to stretch too far, re-orient their project, or perform some sort of gymnastic maneuver to achieve their work.

The waste of motion can also apply to machines, which you can observe when it has to travel for ten or twenty seconds before it actually reaches the product and starts to perform its function. It is far better to have the products and equipment in an easy and comfortable position to prevent stress and delays.

How to reduce or eliminate motion waste

  • Improving workstation layouts to prevent excessive walking, bending, or reaching
  • Arranging methods to allow parts to transfer smoothly from one hand to the other
  • Redesigning the workplace layout to allow for less reorientation of materials
  • Reducing batch sizes

These movements sap time. They can also potentially damage the product and stress the individual. Motion studies first began in the 1900s with Frank Gilbreth, who studied bricklayers and noticed their constant bending to pick up heavy bricks from the ground instead of having the bricks available at a more comfortable height.

Reduce waiting times in the manufacturing process to help eliminate waste.

Reduce waiting times in the manufacturing process to help eliminate waste.


Waiting involves any idle time produced when two interdependent processes aren't completely synchronized. This can be caused by machines, products, people, and information that forces operators to wait or work inefficiently. We spend a lot of our time waiting for various reasons.

Causes of Waste Due to Idle Time

  • Previous operations running over their expected time
  • Deliveries failing to arrive
  • Unreliable people and machines
  • Poor man/machine coordination
  • Need for batch, instead of single product, completion
  • Time required to rework a product

Imagine if you could eliminate the factors that force you to wait and the resulting free time you can use to do something productive.

Avoid overproduction in the manufacturing process.

Avoid overproduction in the manufacturing process.


Overproduction works in two forms:

  • Producing something before it is needed
  • Producing too much of a product, resulting in work-in-progress and surplus stock

Three Main Reasons We Produce Too Much Product

  1. We've always done it, usually in the hopes that customers will buy it. Ideally, you manufacture product based on an accurate analysis or forecast, but this isn't always the case. Big batches may be created because of the time it takes to set up the machines and wanting to use them efficiently. We should try maximizing the amount of time machines run for to minimize the relative time taken to set them up.
  2. We may not trust our suppliers and other internal processes. The extra stock gives us peace of mind in case something goes wrong and products can't be manufactured.
  3. Our production processes are unbalanced. One process may be faster or slower than another, which results in building inventory. Instead of slowing one down or speeding up the other, we blindly produce as fast as we can.

The extra inventory you make needs to be stored and transported, which ends up costing the company money and space. Overproduction is one of the worst kinds of waste because it leads to other wastes and disguises the need for improvement.

How to Reduce Overproduction

  • Working with smaller batch sizes
  • Creating more reliable processes
  • Establishing stable schedules
  • Balancing cells or departments
  • Using accurate forecast information that reflects the actual demand
Avoid over-processing in the manufacturing process to reduce waste.

Avoid over-processing in the manufacturing process to reduce waste.


Over-processing is putting more time and effort into a product than a customer requests. A few examples of this includes painting areas that won't be seen, establishing tight tolerances, and cleaning a product beyond the degree needed.

How many engineering drawings have you seen where the designer specifies an incredibly tight tolerance that, in turn, requires high-tech machinery to achieve? In reality, the product could be produced more cheaply and just as well with a wider tolerance.

How to Avoid Over-Processing

  • Standardizing best techniques for workers to follow
  • Setting clear specifications and quality acceptance standards
An Example of a Defect

An Example of a Defect


Most people think solely of defects when you bring up waste in manufacturing, but they comprise only a small part of the seven wastes.

Unfortunately, defects cost a lot more than you think because it affects more than the product itself. A defect leads to reworking the product/service and the need to fill in reports and hold problem-solving meetings. You lose not only the time and energy spent producing the part, but you also have to reschedule and invest more time and energy to create replacements.

Defect costs are normally depicted as an iceberg. The main costs hide beneath the surface, and most estimates place the true cost of a defect at ten times the initial cost!