7 wastes in Lean Manufacturing

What is waste exactly? In Lean manufacturing, the simplest way to describe waste is as “Something that does not change the physical or chemical characteristics of the product”.  If any activity performed in the manufacturing process does not help in converting the material to its final state is a non-value adding activity. All these non-value adding activities (or wastes) can be broadly classified into 7 different types.

1) Transportation

Definition Transportation is any unnecessary movement of materials from one place to another. This is considered as a waste since it does not change the product physically or chemically, meeting the customer requirement.

How to identify it?

  • Having multiple storage locations causing multiple material movement.
  • Moving materials from production to assembly or to finished goods.
  • High inventory levels using more storage space and hence increasing transportation of materials.
  • Poor facility layout causing more material movement.

Solution – Transportation waste can be reduced by removing temporary storage locations that cause material to be handled twice. All machines and equipment should be placed as close together as possible to eliminate unnecessary material movement.

2) Inventory

Definition – Stock tied up in raw material, work in progress (WIP) or finished goods has a cost and it locks your capital. In addition to the pure cost of your inventory it adds many other costs; inventory needs space, packaging, transportation and defects in transit.

How to identify it?

  • Materials build up between processes (WIP).
  • FIFO (First-In-First-Out) not being followed.
  • Batches of defective products being produced.
  • Additional material handling due to excess storage.
  • Excess raw material procurement from supplier to avail discounts.

Solution- Inventory hides many of the other inefficiencies in your systems – process defects, poor machine utilization, high setup time and poor purchasing processes. Reducing inventory brings all these inefficiencies to the surface, so that they can be solved.
Our suggestion is to concentrate on reducing the work-in-progress. Raw material purchase and finished goods stock generally depends on market fluctuations, seasonality in customer demand, availability of raw materials and commodity price movement and many other factors.

3) Motion

Definition– Any unnecessary movement of people that does not add value to the product is a waste. All of these wasteful motions cost you time (money) and cause stress on your employees and machines.

How to identify it?

  • Looking for tools and parts in the workplace.
  • Excessive reaching or bending to retrieve a part.
  • Walking to fetch a material that is far away.
  • Placing things down and picking it up again for use.
  • Poor plant layout causing excess employee movement.

Solution- Easy access to materials and an efficient work cell design can eliminate these unnecessary motions of operators.

4) Defects

Definition – Producing products that do not meet the customer requirement. It is the obvious waste of all leading to rework/scrap – costing you the resources used to produce it, extra paperwork and even loosing a customer.

How to identify it?

  • Presence of defective products.
  • Employing extra manpower to inspect, rework and repair defective products.
  • Reworking the entire batch of defective products.

Solution – Defects should be prevented wherever possible. Primary objective is educating the operators on identifying and segregating the defective parts, and  solving its root cause to prevent it from happening again. Companies that can afford to install systems to make the process “error free” can implement Poka-Yoke systems and Autonomation.

5) Waiting

Definition – Any idle time stopping from making the material to be converted into a finished product due to non-synchronized operations or departments.

How to identify it?

  • Waiting for getting a confirmation from other department in your company?
  • Waiting for the machine due to product changeover or downtime?
  • Waiting for the materials to be shipped from your supplier?

Solution – Any idle time that does not change the product physically or chemically is as a waste. Few other causes are long setup times, unbalanced operations and inconsistent work methods and hence the result is literally operator waiting for work. Focus on eliminating the operator waiting time completely by making process improvements in the areas causing it.

6) Over processing

Definition – Over processing is putting more into the product than the customer is paying you for. All these activities costs money and time and hence it is a obvious waste to be avoided.

How to identify it?

  • Cleaning and polishing beyond the level customer required.
  • Painting of unseen areas.
  • Performing redundant operations that are not required by the customer.
  • Redundant approvals, extra copies and excess information being gathered and supplied to the customer.

Solution- In most cases, this waste occurs due to lack of correct customer requirements. The objective is to perform only the level of processing that is required to match what is useful and necessary to meet the customer requirements.

7) Overproduction

Overproduction is the worst of all seven wastes since it hides all other wastes and hence the need for its improvement.

Definition – It is nothing but producing more (or faster) than it is required by the next process in line or the customer.

How to identify it?

  • Large lot sizes or batch processing.
  • Unreliable process or unstable schedules leading to excess production.
  • Producing in anticipation of future demand (without accurate information).
  • Unbalanced processes or departments.

Solution – In Lean manufacturing, the aim is to make only what is required and when it is required by the customer – the philosophy of Just in Time (JIT).

  • Initial step is to identify the material and information flow using value stream mapping.
  • Establish single piece flow by rearranging the work place, creating production cells that contain all of the required processes.
  • Use smaller, simpler, dedicated machines rather than “super machines” that can handle every product in the facility.
  • Reduce set up times on our equipment using Single Minute Exchange of Dies (SMED).

After completing these steps, follow just in time manufacturing to enable the production of a product only when it is ordered. Hence you would have not only eliminated overproduction, but you will begin to eliminate and highlight the causes of many other problems within your processes that were hidden by all of this inventory.

7 wastes

To learn more about the 7 wastes in detail or to get our assistance in eliminating them in your workplace, contact us by pressing the button below.

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