04 best practices for manufacturing

7/31/2019 04 Best Practices for Manufacturing

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1M.S Ramaiah School of Advanced Studies - Bangalore

Session 8

Best Practices for Manufacturing

Session Speaker

Prof. Sudhindra Kumar


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1. Judgment Inspection: Separates defective products from good onesafter processing . It prevents from being delivered to customers , butdoes not decrease a companys defect rate.

2. Informative inspection: Investigates the causes of defects and feedsback this information to the appropriate processes so that action canbe taken to reduce the defect rate . The check feedback actioncycle does not begin until after defects occur , it essentially toleratestheir existence.

3. Source inspection: A defect is result , or an effect , usually caused bya simple mistake, through 100 percent inspection at the source, themistake can be corrected before it the mistake can be corrected before

it becomes a defect.

Defects = Zero can be achieved.

INSPECTION TECHNIQUES:

Three major inspection techniques in the field of QUALITY CONTROL are:


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SPC and Elimination of Source of Defect:

Statistical Process Control (SPC) developed in the United

States, is based on the premise that 100 percent inspectionis burdensome and time consuming and can be adequatelyreplaced by sampling inspection and statistics , butstatistics is really no more than qualified guess work - a

certain level of defects is tolerated. SPC is merely a tool ofquality control, it can not eliminate the source of defects.

In a zero Quality Control (ZQC) system 100 percent

inspection is achieved through Poka Yoke, an approachthat is inexpensive and requires little effort.


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Poka yoke is a technique for avoiding simple humanerror at work.

Developed by Dr. Shigeo Shingo, formerly called fool

proofing, to achieve zero defects and eventuallyeliminate quality control inspection.

Translated as mistake proofing or fail - safing fromthe Japanese words

Yokeru to avoidPoka inadvertent errors.

(It was felt that fool- proofing may offend many workers)

The idea behind Poke Yoke is to respect theintelligence of workers or take over repetitive tasks oractions that depend on vigilance or memory and free aworker s time and mind to pursue more creative andvalue adding activities.


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Zero Quality Control has three components that lead to the elimination of defects :

1. Source Inspection - checks for factors that cause errors, not the resultingdefect.

2. 100 percent inspection uses inexpensive poka yoke (mistake proofing )devices to inspect automatically for errors or defective operating conditions.

3. Immediate action - operations are stopped instantly when a mistake is madeand not resumed until it is corrected .

The weightage of importance of these three features can be :

Source inspection - 60%

100 percent inspection ( Poka Yoke) - 30%

Immediate action - 10%

Source inspection is the most important function with 100 percent inspection usingPoka Yoke.


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Defects are wasteful and if they are not discovered they disappointthe customer s expectations of quality .

It is not acceptable to produce even a small number of defective

goods . Poka yoke methods are simple concepts for achieving zero

defect production

Zero Quality Control System

A person is an animal that makes mistakes . Therefore we must

practice poka yoke more than we make errors.

Mistake Proofing A system to detect and prevent mistakes.

Sources ofproblems

Users misuse and abuse of products.

Manufacturers mistakes in conceiving, designingand manufacturing


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A Successful Modern Factory

Inadvertent Mistakes Increase Work

Hiroyuki Hirano, JIT ManagementResearch Institute


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Are Errors Unavoidable?

There are two approaches to dealing with errors:


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One method of preventing errors is inspection.

There are two major types of inspection:


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The User is the Best Inspector


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Three Strategies for ZERO DEFECTS

1. DONT MAKE IT2. MAKE IT TO WITHSTAND ANY USE

3. ONCE YOU HAVE MADE IT USE IT RIGHT AWAY

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The Basic Functions of Poka-yoke

A defect exists in one of two states:

It is either about to occur, or it has already occurred.

Poka-yoke have three basic functions to use againstdefects - shut down, control, and warning.

Recognising that a defect is about to occur is calledprediction.

Recognising that a defect has already occurred is calleddetection.

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Detection Devices toUse for Poka-yoke.

No contact devices

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Summary

Best manufacturing practices are techniques used in the

shop floor for efficient manufacture of products

They are required to eliminate defects in the product duringmanufacturing owing to errors of man, machine or material

They are required to ensure consistent product quality and

reliability, reduce product cost, and avoid wastage

04 best practices for manufacturing

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