Mizenboushi Method (未然防止法 )

GD3: Good Design, Good Discussion, Good

Dissection Prevent a problem before it occurs Author: Tatsuhiko Yoshimura

Mizenboushi

3 stage: Problem solving： Prevention of recurrence Mizenboushi: preventive action before a

problem occurs Example:

Brake pad premature wearing, changing material is Problem Solving, update company standard is Prevention, other action, like looking for other causes, or procedures is Mizenboushi

Mizenboushi must be based on 2 previous stages

Sakichi Toyota’s Words

To cherish the spirit of research and creation and always be ahead of the time

If the product tests have not been completed, do not ask the public to evaluate the worth of the product

Directly grasp the needs of consumers and reflect them into the products

Inspect product quality and business operation, and apply improvements

2.1 Japanese Quality Philosophy

Customer is NO.1 Quality Bench Marking Teamwork (sharing failure information) Continuous Improvement (Kanzen) Genba, Genchi, Genbutsu

Actual place, real condition, actual item Quality is built in during the

manufacturing process Take pride that no inspector is needed

2.2 Quality in Japanese Products

The gap between Japanese, European, and American automotive, is getting smaller

Toyota will still be characterized by quality

(Quality in individual’s work, corporation's overall operation is still different and make difference - Gerry)

2.3 Development of Japanese Products

Development process becomes more and more complex and “heavier”

Requested tests and documentation become a burden

Problem will not decrease by applying control and testing

ISO 9000 itself is not sufficient enough to prevent issue from happening

2.5 Ask Why, Why, 5 times

Initiated by Taiichi Oono, the creator of Toyota Production System

There are many branch and different way to ask why, and have different results

2.6 It might be a little late

When the first custom claim the problem, it might be a little late, even you implement remedy as quick as you can, because plenty of production have been made

Means of Mizenboushi, GD3

3.1 Forecasting and Management

Reliability means “The assurance that a given machinery is functioning properly at future point of time”

COACH: Concentrate: Objectively: And Challenge

Taguchi Method and Robust Engineering

Developed by Genichi Taguchi DOE For evaluating the degree of

impact of parameters, by using the signal to noise ratio

Difference between Japanese and …

Strategically Oriented (Total Optimum)

Tactically Oriented (Partial Optimum)

Different Zero Defect Approach

Just in Time and Jidoka

Just in Time: needs zero defect Jidoka: (自働化 ) This type of automation

implements some supervisory functions rather than production functions. At Toyota this usually means that if an abnormal situation arises the machine stops and the worker will stop the production line. Autonomation prevents the production of defective products, eliminates overproduction and focuses attention on understanding the problem and ensuring that it never recurs. It is a quality control process that applies the following four principles:

Detect the abnormality. Stop. Fix or correct the immediate condition. Investigate the root cause and install a countermeasure

Zero Inventory/Zero Defect

They are stretched target so that to achieve optimum inventory and target defect level

Six Sigma

1 out 1 million Achieved by improvement process MAIC

Measurement Analysis Instrument Control

Conducted by improvement leader (expert) Black Belt and Green Belt

Chapter 4: Good Design

4.1 The basis for achieving reliability

Do not change design Do not simultaneously change at 2

places Establish the good design as

foundation

4.2 What is a good design

Good design is robust design Implement best practice Implement lessons learned Know the critical areas where

failure occurs

4.3 Survey all successful design

Balance all the factors, for example: engine mount stiffness Vs. noise

Exam all the drawings Half of them are good, and half not

4.4 Utilizing failed experience

4.4.1 Conditions for sharing failure experience 1. database of failure experience It is important to share failure

examples within a company

4.4.2 Climate for sharing failure information 1. VP conduct sharing as a engineer 2. Laterally share information 3. Check list 4. Displaying failure examples

4.4.3 Designer’s attitude toward failure 1. It is a job responsibility to make

improvement 2. Superiors must clarify the person

responsible and reprimand him 3. The designer’s sense of ethics is

important 4. Sense of accountability in US and in Japan

are different 5. In US, it is difficult to “exhibit failure

examples”

4.4.4 Interact at starting point It is necessary to have the capability

to read data Designers are to create specific forms

from abstract concepts What sympathizes at base is ‘Lesson’

4.5 To know the critical area for failure

4.5.1 The meaning of robustness Robust Engineering Selection of best seat and tolerable

seat Characteristics of a shock absorber Higher performance or more stable

performance? Look for width, not just height of

performance

4.5.2 Safety factor and robustness ratio

1. Safety factor: change from 10 in 1915 to 4, then 3, then 2.4 (boiler design)

2. Stress/Strength model

3. Larger safety factor is necessary4. Robust design: safety factor bigger,

less stable, maximum SN ratio (Signal/Noise)

4.5.2 Safety factor and robustness ratio

5. Operational window method by Don Clausing

6. The operational window method is used in strength design

7. Quality product cannot be made in a process that cannot produce defective product

Summary of Good Design

Make problems visible at their budding stage

Good design means: to clarify the conditions of Good Design and by not changing the design, and to take note of the area which includes the budding problem by making it standout when a changing is made

Chapter 5, Good Discussion

Good discussion is about DRBFM

5.1 Take note of where changes were made

Let designer mark up the changes Designer usually says: it is a

completely new design, or nothing changes

This could indicate potential problem, because he/she either did not use good design as reference or didn’t notice the change points and impact of those change points

5.2 Conduct good discussions on changing points

5.2.1 The first review is the opportunity for detecting problems Design cannot be made with only a set of

design requirements Need to share information for weakness

points Suppliers might try to hide weakness points

or they don’t even know it. Product engineers must conduct review by themselves

Create a FMEA together with supplier-client

5.2.2 do not measure the worth of FMEA by the thickness of the report

Have you been fooled by the thickness of the FMEA reports?

FMEA can not be prepared unless people who know about stress and strength

To create FMEA unique to the component

Take note of changes, make it meaningful

5.2.3 Development of DFBFM

It is new name This is a problem finding process

that is performed by everyone

Chapter 6

The essentials in implementing DRBFM

6.1 DRBFM as a Detector

1) FMEA and DRBFM are means of finding problem

2) Link FMEA to DRBFM The worksheet still is called FMEA The design review called DRBFM

6.2 Timing of implementing DRBFM

There are about 3 occasions for conducting DRBFM. One is after “Basic Design Concept” One is after “Prototype Design” One is after “DRBTR” and before

“Mass Production” The most important DRBFM is the

first one

6.3 Essentials for implementing creative FMEA

Can be made by one individual or a group

Preparation: Required Spec Usage and environment Construction of parts, function, section Change points and reasons Drawing, sample, FMEA sheet

Prepare DRBFM 1 week before Design Review

6.4 Application of DRBFM

Don’t make a design review to Status Review

Need good preparation in advance To make design review a success Points to note in conducting

DRBFM Conducting DRBFM discussion

FTA Method

Fault Tree Analysis (FTA) is another technique for reliability and safety analysis. Bell Telephone Laboratories developed the concept in 1962 for the U.S. Air Force for use with the Minuteman system. It was later adopted and extensively applied by the Boeing Company. Fault tree analysis is one of many symbolic "analytical logic techniques" found in operations research and in system reliability.

Chapter 7

Good Dissection

7.1 Design review by close examination

Need to conduct DRBTR Test still is last fortress to find

problem How to exam objects

See what you can see See what you can not see Observe side by side Measure them

7.2 How to conduct DRBTR

With the test results on the table The role of computer simulation

and experiment Human eyes with wisdom are

required to find problem

Chapter 8

Expanding Application of GD3

8.1 Filling the gap between organizations with GD3

GD3 is useful where there is a problem in linking organization

Between engineering department and manufacturing department

One way communication conveys only 30% of the party’s intent

8.2 From GD3 to GD4

Good decision is most important

Logistic Curve Theory (S Curve)

Infancy period, growth period, saturation period