Key Lessons in Lean Manufacturing: The 5 Ss, The 5 Whys, The 7 Types of Waste.

PROBLEM: A factory machine stopped working.

WHY? 

It overheated. 

WHY? 

The cooling system failed. 

WHY? 

It was not maintained. 

WHY? 

There was no schedule for maintenance. 

WHY? 

The company did not create one – 

The root cause was revealed. The machine did not just stop working; the company did not have a scheduled maintenance plan. Without this questioning, a user might just replace the cooling system (treating the symptom) instead of fixing the bigger issue, identifying the root cause and preventing recurrence of similar problems. 

The 5 Whys is a root cause analysis technique used to discover the underlying reason for a problem by repeating the question "Why?" five times. It is part of a process which is called Lean Manufacturing.

The Toyota company in Japan has been admired—and studied— worldwide for their standard of automotive reliability. In manufacturing circles they are regarded as the leaders in Lean Manufacturing. It can be said that their way of lean manufacturing was the cause of  Toyota’s success and it is the cornerstone of The Toyota Production System (TPS).

What is Lean Manufacturing?

In short, it is smart production. 

The primary objectives are: less resources, less time, and less effort to produce high-quality products. According to Toyota’s website (global.toyota) it is “A production system based on the philosophy of achieving the complete elimination of waste in pursuit of the most efficient methods.” 

Lean manufacturing is therefore a system designed to maximise efficiency ánd quality by eliminating waste, lowering costs, and shortening lead times. 

Key Components & Tools of The TPS

Built on the two pillars of Just-in-Time and Jidoka, it empowers workers to stop production to fix issues, ensuring only high-quality, needed products are produced. 

• Just-in-Time (JIT): Making only what is needed, when it is needed, and in the amount needed. This minimizes inventory and reduces wasted space and time.” In the Toyota Way, pull means the ideal state of just-in-time: delivering to the customers what they want, when they want, and how much they want.”
• Jidoka (Automation): "Automation with a human touch." Machines or operators immediately stop production when abnormalities occur, preventing the production of defective products.
• Kaizen (Continuous Improvement): A culture where all employees continuously make daily, incremental improvements to work processes. 
• 7 Types of waste: 

1. Overproduction: highly costly to a manufacturing plant. The concept is to schedule and produce only what can be immediately sold or shipped.
2. Waiting: When material flow is poor, whenever goods are not moving or being processed, the waste of waiting occurs. 
3. Transporting: Transporting products between processes is a cost incursion which does not add value to the product. 
4. Inappropriate processing: Toyota is famous for its use of low-cost automation, combined with immaculately maintained machines. 
5. Unnecessary inventory:  A cost no manufacturer can afford. Excess raw materials, work-in-process (WIP), or finished goods that exceed customer demand.
6. Unnecessary motion: Excessive movement and handling cause damage.
7. Defects: Eliminating flaws ensures that each part of the production line will go as planned. Rework or scrap have a direct impact to the bottom line and can result in a tremendous cost to organisations. 

• The 5S Framework: A workplace organisation technique:
  • Sort, 
  • Set in Order, 
  • Shine, 
  • Standardise, 
  • Sustain, 

Each step building on the previous one. The TPS targets zero failures, zero defects, and zero accidents. Each of these targets depends on the organised, well-maintained work environment that 5S establishes. 5S is a cyclical methodology and usually the first lean method which organisations implement.

• The 5 Whys was developed by Sakichi Toyoda, (founder of the Toyota Motor Company.)  5Whys moves beyond superficial analyses of problems to find permanent solutions, preventing issues from recurring. The answer to the final “Why?” should reveal the root cause of a problem, because solving the immediate problem may not solve the problem in the long run. The process starts with a clear problem statement, then ask "Why" in response to each answer until the fundamental issue is found. The number "five" is a rule of thumb; some problems may require more or fewer questions. It is a method designed to fix broken processes, not to assign blame to individuals. Key is to avoid assumptions, each answer should be backed by observed facts rather than speculation. 

The 5 Whys is a core component of lean management and today became widely used in all disciplines; from business, to the classroom, to daily habits, to personal finance and to interpersonal relationships. 

Conclusion

Quote:

“The more inventory a company has… the less likely they will have what they need.”

~Taiichi Ohno

Enterprise Resource Planning (ERP) supports lean manufacturing by eliminating waste, optimizing inventory, and automating workflows. While lean sets the rules for how work should flow, ERP systems provide the data, production schedules, and supply chain visibility required to run that flow at scale.

( This was part 2 on stock control in a 2-part series on: Key Lessons in Lean Manufacturing and Production Management.)