The 8 (7+1) Wastes of Lean Manufacturing

Production of larger quantities before necessary. It is the most expensive waste that generates other waste such as Excessive Lead Time, which makes it difficult to detect defects, a large number of employees, additional storage, and transportation costs due to excess stock.

Common causes of overproduction:

• Wrong sales forecasts
• Production at maximum capacity to maximize the use of machinery/personnel
• Overcoming problems caused by fluctuating peak orders, or production problems
• “If …” Production
• Optimal production batch (lowest total cost)

Occurs when there are unnecessary levels of raw material, many units in the process (WIP), finished products, tools, or any necessary goods/resources.

Excess stock hides issues such as production imbalances, delayed supplier deliveries, defects, machine downtime, long settings, long production changes, and more.

Occurs when goods are not moving or not being processed: In traditional batch-and-tail production, the longest Lead Time of the products is closely related to waiting at each stage for the next operation.

Common reasons for waiting:

• Poor material flow, large batch production & capacity blockages.
• Machine downtime & material shortages.
• Long production change times & no production plan.

Any deviation that requires the reprocessing of the product/information

Associated costs include:

• The cost of waste
• Quarantined stocks
• Re-inspection
• Reprogramming and loss of capacity
• Customer satisfaction

Physical movements that employees exercise excessively among other reasons due to a lack of planning in the ergonomic field, providing low productivity and muscle fatigue.

This waste is seen in activities such as:

bending, stretching, walking, lifting, reaching something, searching, and sorting.

Often known as “using the sledgehammer to break a nut”

Examples for this waste:

• Taking steps that are not necessary to perform a process due to poor layout and arrangement of machinery
• Inefficient processing due to inadequate/poor design of utensils and products
• Provide higher quality or more control than necessary

It is related to excessive movement and handling of materials over long distances.

This waste is created for reasons such as:

• Inadequate transport equipment/techniques
• Incorrect location of equipment
• Large batch management
• Long distances between processes

Loss of ideas, skills, improvements, and learning opportunities by not hiring or disobeying your own employees. This happens when employees’ time and skills are not used properly.

• Authority and limited liability of employees in basic activities.
• Inadequate or low-availability tools to do their job.
• Lack of preparation to perform basic tasks.
• Disobedience to employees’ ideas.
• Using people for tasks that can be automated or assigned to other people with other technical skills.