Lean Concepts Study Guide

Question 1

Kaizen

Answer 1

• Improvement on a continuous basis.
• Originated in Japan, Kai means change and zen means for good
• Per concept, everything can be improved
• Applied in operations helps improve and increase efficiency of different processes in an organization
• Minimize waste, improve customer satisfaction, augment the business procedures and maximize operational efficiency, implementing and speed up the change process

Question 2

Kaizen Philosophy

Answer 2

• Not any specific tool but a philosophy which is rooted in many different process improvement methods like Total Quality Management (TQM), just-in-time(JIT) or as simple as employee suggestion boxes.
• Implementation is not the responsibility of top management or any specialized time, but the role is vested with each and every employee of the organization, who should look for gaps and inefficiencies in the existing processes and procedures, suggest changes for improvement and finally, helps in implementing those changes for continuous and sustained improvement.

Question 3

Implementing Kaizen Steps

Answer 3

1. Define the problem/issue
2. Document the current situation
3. Visualize the optimum situation
4. Measurement targets to be defined
5. Brainstorm about the possible solutions to the issue
6. Develop the plan
7. Implement the plan
8. Measure and compare the actual results with the targets to learn about variances, if any
9. Prepare documents to summarize
10. Create action plans and sustaining plans

Question 4

Benefits of Kaizen

Answer 4

-When the organization works towards continuous improvement, it can reap the benefits of improved efficiency and effectiveness in all domains of the organization.

1. Reduction in waste (muda)
2. Enhances satisfaction - customers, employees, stakeholders
3. Increases employee commitment
4. Retention rates increase - employee and customer
5. Competitive edge
6. Working teams in the organization work more efficiently, the problem solving skills of the employees enhances and finally, the organization is able to recap the benefits of synergy by maintaining a work-culture that is improvement-oriented and innovative

Question 5

Kaizen Events

Answer 5

• The word kaizen recognizes the philosophy of kaizen and differs when we talk about Kaizen events.
• Kaizen events denotes the action which aims at improving the output of an existing process
• Aim is to achieve improvements

Process:

• Generally a leader is appointed who identified the opportunity for improvement and/or plan and lead these changes.
• The event leader integrates and gathers the operators and other employees attached to the particular process at one place.
• They then map the existing process, and then suggest and implement the improvement process.

Question 6

Differences between Kaizen Philosophy and Kaizen Event

Answer 6

• Kaizen is an continuous improvement philosophy while kaizen events are undertaken for short term tasks to improve any particular process
• The responsibility for kaizen is vested with each and every employee of the organization but kaizen events are facilitated by an appointed facilitator

Question 7

Running a Kaizen Event

Answer 7

• A Kaizen event can be conducted for a short term, can last from one day to a few weeks, depending on the event and identified issue.
• There should be a pre-planning and tentative schedule of the event should be framed before actually getting into implementing an event.

Planning steps to consider:

• Train or hire a facilitator
• Gain understanding and commitment from management
• Establish the boundaries of the event
• Define the purpose of the event
• Communicate about the event to everyone in organization
• Select the team for implementation
• Identify the measures of improvement in performance
• Implement the improvement measures

Question 8

5S Workplace Organization

Answer 8

• 5S’s detail how to create a workplace that is visibly organized, free of clutter, neatly arranged, and sparkling clean. The 5S system is often a starting place for implementing lean operations.
• Visual system and Kaizen event

1. Sort
2. Set in order/Straighten
3. Shine
4. Standardize (Hard)
5. Sustain (Hard)

Question 9

5S Workplace Organization Breakdown

Answer 9

1. Sort: Remove unneeded items
2. Set in order/Straightening: Arrange the required and rarely required items for ease of accessibility
3. Shine: This involves cleaning the work area and equipment
4. Standardize: This involves developing checklists, standards, and work instructions to keep the area in a clean and orderly condition
5. Sustain: Most difficult of the 5S, management should empower the employees by allowing them to take ownership of their work areas

Question 10

Classic Wastes/3M of Wastages

Answer 10

• Blockage against the productivity
• Muda, Muri, and Mura

Literal Meanings:

1. Muda: waste
2. Muri: overburden
3. Mura: unevenness

Question 11

Muda

Answer 11

Wastage of unnecessary activities

7 Basic Types:

1. Transportation
2. Inventory
3. Motion
   
   1. Bending
   2. Reaching
   3. Searching
4. Waiting
5. Over-processing
6. Overproducing
7. Defects

Question 12

Muri

Answer 12

• Wastage caused due to overburdening your machines and stress
• Causes stress and pressure on your resources - both human and physical by placing unnecessary and unreasonable demands on them.
• Muri leads to Muda by adding non-value adding steps within the process

Instances:

• Working on processes without proper training
• Unclear instructions
• Lack of proper tools and equipment
• Poor communication tools

Question 13

Mura

Answer 13

• Type of inconsistency or irregularity
• This inconsistency can be witnessed in many parts of a production system like material flows, uneven demands of the customer, fluctuating inventory, inconsistend quality of goods produced, uneven training of staff, uneven distribution of workflow and erratic work schedules

Question 14

Process Mapping Symbols

Answer 14

Question 15

Main Object of Lean System

Answer 15

• Is to augment effectiveness and efficiency of various processes in the organization by reducing waste in operations like long lead times, defects and bottlenecks in material, and information flows.
• Tool used to do so is Value Stream Mapping

Question 16

Value Stream Mapping

Answer 16

• Visual representation of the flow of materials and information throughout the organization.
• Helps to identify, demonstrate, reduce waste, and finally create effective flow through all the processes in the manufacturing organization
• Constitutes all the value added as well as non-added values required to make the product
• Consists of the process flows starting from the raw materials to make the product finally available in the hands of the customer

Question 17

What does Value Mapping Stream Do?

Answer 17

• Graphically illustrates the flows of materials and information in a process.
• Displays the interactions between multiple organizational functions - both manufacturing as well as ancillary functions
• Pinpoint the problem areas, inefficiencies, defects, bottlenecks more efficiently as it integrates and maps the information flows, material flows along with the sequence of tasks. It even shows the cycle-times and lag-times between different tasks
• Involves all stakeholders in each stage of the process and hence, it becomes easy to develop and implement countermeasure to facilitate cultural change in the organization.
• Provides proper presentation of all the limiting factors
• Continuous improvement is facilitated since the direction can be focused on lean transformation teams, front line supervisions, and upper management

Question 18

Poka-Yoke Error-Proofing

Answer 18

-Act of making errors impossible through great design. Defining requirements or ensuring continuous flow are good things, but not strictly part of error-proofing.

Question 19

Theory of Constraints (TOC)

Answer 19

• Views all processes as a chain of events that executes sequentially. Rember a chain is only as strong as its weakest link. A 5 step process is only as productive as its slowest step
• Helps you find the constraints, Lean (and TOC) helps you improve them, Six Sigma help you eliminate any errors.

5 Steps:

1. Identify system’s constraint
2. Decide how to exploit
3. Elevate the constraint
4. Subordinate everything else
5. If the constraint breaks, identify the new constraint

Question 20

How is Lean Different from Six Sigma?

Answer 20

Lean is elimination of waste.

Six Sigma is about elimination of variation.

Six Sigma Goal:

-Produce output that is consistent and free of defects. Identify flaws, determine their cause, and eliminate them

Lean Goal:

-Lean must begin with the view that the product and process that creates it must add value to the customer. Anything that does not directly add value to the customer is waste.

Six Sigma or Lean First?

Because lean is about creating an efficient process and six sigma is about making the process deliver what the customer wants with little variation. You don’t want to do lean first because you could make a perfectly-efficient, process that delivers something that the customer doesn’t want. If something doesn’t need to be done in the first place, there is no point in doing it well.

Question 21

Variation

Answer 21

-Lack of consistency

Why Measure Variation?

• Reliability: We want our customers to know that they’ll always get a certain level of quality. Every product needs to fit specific parameters
• Costs: Variation costs money. So to lower cost, we need to keep levels low
• Variation is the square of a sample’s standard deviation

Variation = SD²

Question 22

Types of Variation

Answer 22

1. Common Cause
2. Special Cause

Question 23

Common Cause Variation

Answer 23

-Variation happens in standard operating conditions. Fluctuations might occur due to:

1. Temperature
2. Humidity
3. Metal quality
4. Machine wear and tear

Common cause variation has a trend that you can chart. In the factory, product differences might be caused by air humidity. You can chart those differences over time. Then you can compare that chart to weather bureau humidity data.

Question 24

Special Cause Variation

Answer 24

-Occurs in non-standard operating conditions. Could occur if:

1. Substandard metal was delivered
2. One of the machines broke down
3. A worker forgot the process and made a lot of unusual mistakes

This type of variation does not have a trend that can be charted. Imagine a supplier delivers a substandard material once in a three month period. Subsequently, you won’t see a trend in a chart. Instead, you’ll see a departure from a trend.

Question 25

It is important to separate Common Cause and Special Cause because:

Answer 25

• Different factors affect them
• We should use different methods to counter each

Treating common causes as special causes leads to inefficient changes. So too does treating special causes like common causes. The wrong changes can cause even more discrepancies.

Question 26

Run Charts and Common Cause Variation

Answer 26

Run Chart definition: a line chart of data plotted over time. A run chart graphically depicts the process performance of data values in time order. Viewing data over time gives a more accurate conclusion rather than just summary statistics.

Use run charts to look for common cause variation

1. Mark your median measurement
2. Chart the measurements from your process over time
3. Identify runs. These are consecutive data points that don’t cross the median marked earlier. They show common cause variation.

Question 27

Control Charts and Special Cause Variation

Answer 27

Control Chart definition: A Control chart is one of the primary techniques of statistical process control (SPC). The control chart is a graphical display of quality characteristics that have been measured or computed from a sample versus the sample number or time. The control chart was invented by Walter Shewhart at Bell labs in 1920.

-A graph used to study how process changes over time. Always has a central line for average, an upper line for upper control limit, and lower line for lower control limit. The control limits ±3σ from the centerline.

Control Charts for Special Cause Variation

1. Mark your average measurement
2. Mark your control limits. There are 3 standard deviations above and below the average
3. Identify data points that fall outside the limits marked earlier. In other words, above the upper control limit or below the lower control limit. These show special cause variation.

Question 28

Takt Time

Answer 28

Takt Time= (Net Time Available for Production) / (Customer’s Demands)

Steps

1. Calculate the Net Available Time
   
   1. Includes planned downtime
      
      1. E.g. Breaks, lunches, clean-up time, team meeting, TPM
   2. Does NOT include
      
      1. Material outages, breakdowns, member lateness, changeovers
2. Calculate The Customer Demand

Question 29

Total Productive Maintenance (TPM)

Answer 29

-A series of methods, originally pioneered by Nippondenso (a member of the Toyota group), to ensure every machine in a production process is always able to perform its required tasks so production is never interrupted.

Question 30

Theory of Constraints (TOC) Drum-Buffer-Rope

Answer 30

1. Drum: Stands for physical constraints
2. Buffer: Additional lead time
   
   1. Buffer is place before and after governing constraint
3. Rope: Work release mechanism