Download - Mizenboushi Method
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
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
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
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
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.
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
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