8 Wastes In Lean Manufacturing

A waste is anything which do not add any value to the customer requirement. Once again a waste is any material or operation or activity, which do not add any value to the customer requirement. There are 8 types of waste in a manufacturing industry. I will explain one by one with example. Before that, one more thing, if we identify and eliminate all these types of wastes in an manufacturing industry, we can say we have implemented lean manufacturing in that industry.

These wastes can be collectively called as muda. Have a look at our article on muda mura and muri.

1. Transportation

Transportation is the movement of material from one place to another. Here most important thing is the movement distance. In lean manufacturing we will try to reduce the movement distance as minimum as possible. Because the transportation is not adding any value to the customer product.

Transportation requires additional cost for energy and manpower charges and also it will increases the chances of damage to the product while in movement. Transportation can be within the shop floor and outside the shop floor.

Example : A customer want a product P. Suppose it has three operations and its done in a three storied building. 1st operation is done at 3rd floor, 2nd operation is done at 2nd floor and 3rd operation is done at 3rd floor.

Here we can see an unnecessary transportation of the work in process inventory from 3rd floor to 2nd floor after 1st operation and from 2nd floor to third floor after second operation. This can be eliminated by moving 2nd operation work station to 3rd floor.

Here the operator takes 2 minutes for the transportation. Suppose this transportation is eliminated by moving the work station, this 2 minutes an be saved and the operator can be involved in other value adding activities for this 2 minutes.

2. Inventory

Inventory means the storage of materials or finished goods, which are waiting, either to be processed or to be dispatched. We cannot reduce inventory to zero. There should be a minimum inventory, otherwise we cannot do a manufacturing process.

But if that inventory is excess that will lead to waste. The organizations money will be tied up in the inventory, and that money cannot be used for nothing, until its converted to what customer wants. Inventory will also consume large floor space which is again a cost to the company.

Example

Suppose a company purchases raw materials in bulk for producing a product for one year and stored in its warehouse, it is a waste, because it will consume large amount of money and floor space.

3. Motion

Motion waste is the unnecessary movement humans or machines while doing an operation. The time duration of this waste will be less but it will be repetitive.The difference between transportation waste and motion waste is, motion waste will be occurring while doing an operation.

The below two videos will demonstrate clearly the motion waste. First video includes unnecessary motion and second video is after eliminating the unnecessary motion. Please click the play button and and watch the two videos carefully.

[evp_embed_video url=”https://knowindustrialengineering.com/wp-content/uploads/2019/12/motion-2.mp4″]

This two videos are the assembly operation of pen. In the first video we can see two unnecessary motions,

1. Picking up of the barrel with right hand giving it to the left hand
2. Movement of right hand two times for picking ink tube and bottom cap.

In the second video, these motions are eliminated by following improvements

1. Picking up of barrel with the left hand itself.
2. Picking up of ink tube and bottom cap in one movement.

I hope its very clear from the two videos. We can improve the efficiency by eliminating unnecessary motions.

4. Waiting

If any material or human waits before an operation or process, its a waste in lean manufacturing. It will increase lead time and throughput time. Waiting is not adding any value to the customer requirement. If a machinery is idle due to no load, its waiting for the operation and its under utilized.

Example

Suppose there is three operations A, B and C for producing a product. The cycle time of the operations are 5, 10 and 5 minutes respectively. And we are allocated one person each for doing an operation, in respective work station.

While running the assembly operations, we can see the two operators doing the operations A and C will have to wait for 5 minutes per unit. That means the half of the production time they are doing nothing.

5. Over production

If a product is produced beyond the demand and stored in warehouse, its an wastage. Because, It will require space for storing the finished goods which requires additional cost. Also if the customer changes the design or specifications of the product, this inventory creates no value to the customer.

6. Over processing

If an operation is done to achieve what a customer do not want, it is called over processing. A lot of energy and money will be spend for doing the operation.

Example

Suppose the only customer requirement is a cylindrical rod with a hole through its center and nothing else. And if we provide a chamfer at both ends it will be an over processing.

7. Defects

Defects are the non conformance of the product against its customer requirement. When a defect occurs on a product either it is scrapped or reworked and both reworking and scrapping is a loss of money.

8. Under utilized skills of employees

All employees in an organisation will have different skills and knowledge. If we do not identify these skill and knowledge, and do not apply this for improvement activities or solving a problem in an organisation, that skill is considered as waste. Because, who knows that will lead to a huge benefit. Kaizen can be implemented to utilize these skills

Thank You for reading….

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