TW Chapter 4: Create Initial Process Stability

Question 1

What is stability, and where does it come from?

Answer 1

Stability is the capability to produce consistent results over time. It comes from consistency in process.

Question 2

What is the first step in creating lean processes?

Answer 2

Achieving a basic level of process stability

Question 3

What is the primary objective of developing stable processes?

Answer 3

Reaching a consistent level of capability

Question 4

What are some indications of an unstable process?

Answer 4

1. High variation in performance measures
2. Changing the plan often when a problem occurs
3. No observable consistent pattern or method to the work
4. Random batches or piles of work in process (WIP)
5. Island processes (sequential operations that operate independently)
6. Inconsistent or nonexistent flow
7. Use of “usually, normally, etc.”, followed by “except when…”
8. Statements like “We trust the operators to make decisions about how the work is done” which reflects a misguided application of employee empowerment

Question 5

What is meant by “clearing the clouds?”

Answer 5

The initial process of stabilizing processes, so that the confusing marginalia of non-value added work can be removed and the essential processes clarified

Question 6

What is the primary objective of the stability phase of the continuous improvement cycle?

Answer 6

Create a basis for consistency so that ‘reality” can be seen and random activities removed, thus establishing a foundation for true improvement

Question 7

What does “perfect stability” cause problems?

Answer 7

Because achieving stability without going through the rest of the continuous improvement cycle leads to instability, new efforts to get back to the initial stability, and finally a process that never improves

Question 8

After Identifying Large Waste, what is the first step?

Answer 8

Develop a thorough understanding of the situation prior to beginning corrective action. Standing in the circle can help do this

Question 9

What are standardized work tools used for?

Answer 9

Analyzing and understanding waste in the operation

Question 10

What are the three critical elements in analyzing work and identifying waste when using standardized work tools?

Answer 10

1. Identify the basic work steps (ie. every time an employee walks or moves his hands)
2. Record the time for each step
3. Draw a picture of the work area and the operator’s flow within the area

Question 11

What is the benefit of Consolidating Identified Waste Activities?

Answer 11

It collects small waste, making cleaning it a necessity. If these small wastes were scattered among people, it would be more difficult to bother with addressing it.

Question 12

What are the Stability Phase Strategies?

Answer 12

1. Eliminate “big” waste
2. Consolidate multiple waste activities to make it visible and provide focus
3. Improve operational availability (OA)
4. Eliminate or reduce variability

Question 13

What are the two types of lost time?

Answer 13

1. In-cycle losses: time loss that occurs while the equipment is operating (recurrent losses of second for every work cycle)
2. Out-of-cycle losses: time loss from non-operational equipment

Question 14

What are the two forms of variability?

Answer 14

1. Self-inflicted variability–controlled by a person
2. External variability–variability from customers, suppliers, and inherent to the product. May not be changeable, but the waste from variability can be mitigated

Question 15

How does isolating variability work, according to the 80/20 rule?

Answer 15

80% of the total variation comes from 20% of the product. By isolating this variable product in its own line, we reduce variability on the main line.