According to Lean manufacturing, there are 7 types of wastes in any manufacturing company. They are:

1. Transportation
2. Inventory
3. Motion
4. Waiting
5. Over Production
6. Over Processing
7. Defects

1) Transportation

Explanation – Transportation is any 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. Transportation cannot be completely eliminated, but “unnecessary” transportation can be eliminated. In general, transportation can be reduced.

How to identify it?

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

Solution – Transportation waste can be reduced by removing temporary storage locations that cause excessive transportation. Establishing Continuous Flow production where the downstream processes are close to each other also reduces transportation.

2) Inventory

Explanation – Stock tied up in Raw Material, Work-In-Progress (WIP), or Finished Goods is called Inventory and while storage there is no value addition in the product, So Inventory is treated as a waste. Excess Inventory locks up the capital and space. It also requires effort and time to retrieve and may cause damages during storage and transit. So, Inventory should be maintained at the optimum levels.

How to identify it?

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

Solution- Inventory(WIP) 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 depend on market fluctuations, seasonality in customer demand, availability of raw materials and commodity price movement, and many other factors. So focusing on reducing WIP is a good way to reduce a lot of wastes.

3) Motion

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

How to identify it?

• Searching 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 them up again for use.
• Poor plant layout causes excess employee movement.

Solution- Easy access to materials and an efficient work cell design can eliminate these unnecessary motions of operators. Follow 5S to improve the workplace(Set In Order).

4) Waiting

Explanation – Imagine we have 3 resources for manufacturing; Material, machine, and People. Waiting happens one of these resources wait for the other 2 resources. While waiting there is no value addition in the product.

How to identify it?

• The difference in cycle times between the processes
• People watching the machines run
• Set-up change / Change-over time
• Break-downs of machines

Solution – Line Balancing to make sure that all the operations have less variation in cycle times, Creating cells where 1 operator can work on more than 1 machine, Reducing the Change-over time through SMED and break-downs by following TPM.

5) Over-processing

Explanation – Over processing is putting more effort/processing into the product than the customer is paying for. All these activities cost money and time and hence it is an obvious waste to be avoided.

How to identify it?

• Cleaning and polishing beyond the level customer required.
• Multiple Inspections, Counting, etc. between processes
• Redundant approvals, extra copies and excess information being gathered and stored in the company

Solution- In most cases, this waste occurs due to a 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. Improving communication between the teams would also reduce this waste.

6) Overproduction

Explanation – Producing more than the customer’s requirement is Over-Production. The customer here refers to Internal and External Customers. All the operations must produce only the quantity required in the downstream processes.

How to identify it?

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

Solution – Establishing Continuous Flow and eliminating Batch Processing is the key solution to reduce over-production. Using tools like SMED, TPM, and Pull system, Over Production can be reduced.

7) Defects

Explanation – Producing products that do not meet the customer’s requirements. It is an obvious waste leading to rework/scrap – costing you time, effort, and customer satisfaction.

How to identify it?

• Presence of defects.
• Employing extra manpower to inspect, rework and repair defective products.
• Frequent Customer Complaints.