3. POKA-YOKE
• ‘POKA’ means ‘Mistakes’ & ‘Yoke’ means ‘Avoid’.
• It’s objective is to achieve Zero Defects.
• Poka-yoke is a quality assurance technique, the aim of poka-yoke is to eliminate
defects in a product by preventing or correcting mistakes as early as possible.
• Term adopted by Dr. Shigeo Shingo as a part of Toyota production System in
1960.
• It was originally described as “BAKA-YOKE”, but this name mean “fool-
Proofing” so the name was changed to the Poka-yoke.
4. WHAT IS ERROR ???
• A MISTAKE : DEVIATION FROM WHAT IS CORRECT, RIGHT OR TRUE .
• HOW TO PREVENT ERROR
• OLD WAY SCOLD PEOPLE
RETRAIN THEM
TELL THEM TO BE MORE CAREFULL
• NEW WAY TRAINING AND MOTIVATION
EASY WAY TO DO JOB
5. Processing errors Wrong parts
Missing Operation Damaged materials
Inappropriate procedures Tools or equipment
improperly prepared
setup
or
Missing parts
Human Errors
Missing information
TYPICAL ERRORS
6. Help Operators to avoid mistakes in their work caused by
choosing the wrong part, leaving out a part, installing a
backwards, etc.
part
Involves the implementation of fail-safe ways methods that
detect or prevent human and machine error at or near the
source.
Provides instant feedback and prevention of quality problems
POKA-YOKE OVER ERRORS
7. Helps people and processes
Refers to techniques that
mistakes.
make it impossible to make
Helps drive defects out of products and processes and
substantially improve quality and reliability.
WHY IS IT IMPORTANT?
8. Used to fine tune improvements
from six-sigma.
and process designs
Use the ideas and methods in product and process
design which can eliminate both human and mechanical
errors.
CONTD…
9. It is a technique, a tool that can be applied to any type of
process be it in manufacturing or the service industry.
Poka-yoke can be used wherever something can go
wrong or an error can be made.
WHEN TO USE IT?
10. Errors can be of any type-
Processing Error: Process operation missed or noti.
performed per the SOP.
Setup Error: Using the wrong tooling or settingii.
machine adjustments incorrectly.
Missing Part: Not all parts included in the assembly,
welding, or other processes.
Improper part/item: Wrong part used in the process.
Operations Error: Carrying out an operation incorrectly;
having the incorrect version of the specification.
Measurement Error: Errors in machine adjustment, test
measurement or dimensions of a part coming in from a
supplier.
iii.
iv.
v.
vi.
CONTD..
11. Step by step process in applying poka-yoke:
Identify the operation or process1.
Analyze the 5-Ws and understand the ways a process can
fail.
2.
Decide the right Poka-yoke approach, such as using a,3.
Shut out Type: Preventing an error being made, or an
Attention Type: Highlighting that an error has been made.
HOW TO USE IT?
12. Determine whether a4.
Contact Method
Constant Number or Counting Method
Motion-Sequence Method
Trial the method and see if it works.5.
Train the operator, review performance and
success.
measure6.
CONTD..
13. COMMON DEVICES USED IN POKA-YOKE
SYSTEMS
• The common devices used in Poka –Yoke systems are:
• 1. Guide pin
• 2. Blinking light and Alarms
• 3. Limit Switches
• 4. Proximity switches(sensor)
14.
15.
16.
17. The methodology of poka-yoke are:
1. Identify Problem
2. Observation at workstation
3. Brainstorming for idea
4. Select best idea
5. Implementation Plan and Implementation
6. Monitor and sign off
18. Step 1: Identify problem
In this stage the complaints coming from the customers (Both internal and
external customer) are collected. The principle of standard is determine by
considering various criteria’s like number of complaints from the customers&
PDI(pre dispatch classify), the quantity of detected by quality control, materiality
defects and then data is collected broadly. As per the analysis all results of the
collected data company plans for developing poka-yoke system for the selected
problem. In the way in first stage the problem is selected
Step 2 :Observation at work stations
In this step the actual on site study of the problem is carried out. The causes behind the
problem are sort out by using fishbone diagram (fishbone diagram is cause and effect diagram
given by Japans management guru Ishikawa).The causes may be related to man skill, machine,
material or method accordingly the complete sorting is carried out.
19. Step 3: Brainstorming for Idea
This is a technique to capture all creativity and skills of employee’s .In brainstorming
session the problem under study is put forward to committee. Then study problem given by all
members and give various solutions to avoid that defect. As each person has one uniqueness this
step concludes with various alternative solutions for same problem.
Step 4: Select best ideas
After getting all various alternative solutions it is time to select best one out of all
collected solutions. Criteria for selection may be cost, problem create after installation, time
required, changes in existing system, opportunity to develop new solutions, simplicity in
operation etc. By referring all selection criteria’s committee concludes With one best solution.
Step 5: Implementation plan and implementation
This step is concerned with implementation planning& installation. It deals with material
requirement, processing the material and finally manufactured mechanism is implemented at
actual working site.
20. Step 6: Monitoring and sign off
The produced products are checked for defects under study also the performance of poka yoke system is
also monitored and project is shut downed.
