2.  Poka -yoke is a Japanese improvement
strategy for mistake proofing to prevent
defects from arising during production
processes.
 It’s aim is to achieve ‘zero defect’

3.  Developed by Shigeo Shingo in 1961
 Poka means mistakes yokeru means avoid
 Poka-yoke refers to techniques that make it
impossible to make mistakes.
 Poka-yoke techniques can drive defects out
of products and processes and substantially
improve quality and reliability.

4.  Errors can be of any type-
i. Processing Error: Process operation missed or not
performed per the SOP.
ii. Setup Error: Using the wrong tooling or setting
machine adjustments incorrectly.
iii. Missing Part: Not all parts included in the assembly,
welding, or other processes.
iv. Improper part/item: Wrong part used in the process.
v. Operations Error: Carrying out an operation
incorrectly; having the incorrect version of the
specification.
vi. Measurement Error: Errors in machine adjustment,
test measurement or dimensions of a part coming in
from a supplier.

5.  PREVENTION BASED
Prevents the defects from occurring
 DETECTION BASED
Detects the defects and prevent its progress

6.  CONTROL METHOD
 This method senses a problem and stops a
line or process, so that corrective action can
take place immediately
 EXAMPLE: Assembly operation in which one
component is missing before actual assembly
whole operation is stopped

7.  This method signals the occurrence of a
deviation or trend of deviations through an
escalating series of buzzers, lights or other
warning devices
 This method does not shut down the process
on every occurrence

8.  CONTACT METHOD
 This method detects any deviation in shape,
dimensional characteristics or other specific
defects, through mechanisms that are kept in
direct contact with the part
 Fixed Value Method: This method is used in
operations, where a set of steps is
sequentially performed.
 A sensor counts the number of times a part is
used or a process is completed and releases
the part only when the right count is reached.

9.  Motion Step Method:
 This method ensures that a process or
operator does not mistakenly perform a step
that is not part of the normal process.
 An example of this is colour coding of
electronic components on drawings and totes
to prevent using mixed or incorrect parts.

10.  Remove defect from root cause or source
 Faster detection and correction
 Lesser attention from workers/operators
 Improve safety of workers
 Improves equipment effectiveness and
assures higher reliability

11.  Requires special expertise on instrumentation
knoweledge
 Implementation cost is high
 Training of workers is a must which adds the
cost