Quality Control in Production Management

8/12/2019 Quality Control in Production Management

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Quality control Notes


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TOPICS

Standards and specifications, Quality Assurance and QualityCircles

Statistical Quality Control

Control Charts for Variables- Average, Range and S.D.,

Control charts for Attributes- fraction defective and number ofdefects,

Acceptance Sampling Plans, OC Curve,

Work Study,

Various techniques in the Methods Study for identifying the most

appropriate method. Work measurement - its uses and different methods,

computation of allowance and allowed time.


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INTRODUCTION

The act of determining conformance or non-

conformance of the expected performance is

the function of inspection.

Basis for inspection is usually aspecification: inspection standard or

quality standard


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QUALITY

Sum of att r ibutes or propert iesthat

describe the product.

The quality of product or service is a

customerspercept ion of the degree towhich the product or service meets his or

her expectat ions.

It is anasset which may be offered to thepotential customer of a product or a service.

CD LEWIS


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QQuest of excellence

U- understanding customers needs

AAction to achieve customers appreciation

L- Leadershipdetermination to be a leader

I- Involving all people

TTeam spirit to work for a common goal Yyardstick to measure progress.


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QUALITY CHARACTERISTICS

Technical

Psychological

Time based items

Contractual

ethical


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TYPES OF QUALITY

Kanos : Indifferent quality, expected quality, one

dimensional quality, exciting quality

Shibas: Quality level-1: fitness to standard

Quality level2: fitness to needs

Quality level3: fitness to costs (preventive,

appraisal, internal failure- rework,retest,downgrading , external failure

Quality level -4: fitness to hidden needs


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DIMENSIONS OF PRODUCT

QUALITY

Performanceintended use

Features - appeal

Reliabilitylikelihood of breakdowns/repairs

conformances

Serviceabilityspeed, cost and convenienceof repairs & maintenance

Appearance Deniability

Perceived quality


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QUALITY CONTROL

All those functions or activities that must be

performed to fulfill the companys quality

objectives

According to Bethe, Atwater and Stackman:

It is systemat ic con trol of those var iables

encountered in a manufacturing process which

affect the excellence of the end product. Suchvariables result from the appl icat ion of

materials, men, machines and manu factu r ing

cond i t ions


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Dr. W.EDWARDS DEMING

Set quality standards

P- Plan, D- Do( produce), CCheck(inspect,

feedback), AActcorrection of process

Replan for long-term quality control

14 principles

Quality control is the technique of management for achieving

required standard of products

PDCA cycle


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OBJECTIVES OF QUALITY

CONTROL

Assess the quality

Satisfies the need of the customers

Take necessary remedial steps

Suggest suitable improvements

Develop quality consciousness

Assess the various techniqes Reduce wastages


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FUNCTIONS OF QUALITY

CONTROL DEPARTMENT Design the product/servicemeets the customers

requirement/safety

Pass instructions and provide information/solutionproductionpersonnel

Use standards materials/components

Train staff/operators

Develop quality awareness

Evaluate critically the functioning of inspection,design andproduction department

Reduce scrap, wastage & spoilage After sales service- satisfactory level

To prevent rather than detect defectives

Adoption of various measures/develop processess


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IMPORTANCE/ADVANTAGES OF

QUALITY CONTROL Reduction of costs

Improvement in the morale of employees

Maximum utilization of resources

Increase in sales

Consumers/employees satisfaction

Improves reputation

Uniformity in quality

Manufacturer and consumer relations

Improvement in technical knowledge, design,process

Higher operating efficiency


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STEPS IN QUALITY CONTROL

Control of engineering quality

assist, review,validate,audit,provide info

Control of purchase material quality

Assist,review,assure,intiate

Control of manufacturing quality

Evaluate &

approve,assure,establish,perform,collect &

analyse,,initiate,conduct,control Actions supporting the product after delivery

QUALITY CONTROL IN MANUFACTURING ORGANISATION:

Inspection: How often, when, where

SQC


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Quality control through STANDARDS

Documentsacceptable conditions orbehaviours

Base-line

Minimum criteria Written or unwritten

Voluntary or mandatory

Relative to time, materials, performance ,reliability and appearance or any quantifiablecharacteristics


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DIFFERENT STANDARDS Preparation of technical specification

Procurement of raw material Engineering and design specification

Manufacturing specifications

Administrative specifications

Test specifications

Product specifications Preparation of standards on procedures and equipment used for

inspection and testing

Preparation of standards on manufacturing process, methodsand tooling

Preparation of codes of practice to be used for guidance during

manufacturing or inspection Preparation of standards on types and design of final products.

Company level, group level, national levelBIS, international level - ISO


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PURPOSE OF STANDARDS

Educate, simplify,conserve, base upon which

to certify


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SPECIFICATIONS

Marketing dept --- designengineering dept----committeeprepares detailedspecifications

SPECIFICATIONS: detailed descriptions orlisting of the characteristics of material partsand components used in making a product.

Technical specifications

Performance specifications

brand name


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QUALITY CONTROL METHODS

Just in timestockless production/repetitive

manufacturing system

Quality at the source

Inspection

SQC

Quality circles


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QUALITY CIRCLES

A small group of employees who meet

regularly to undertake work related

projectsdesigned to improve working

conditions, spur mutual self-development andto advance the company, all by using quality

control concepts

A steering committee of top managementofficials, facilitators, circle leaders and circle

members.


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QUALITY CIRCLES

Quality control

Selfdevelopment

Mutual development

Flowcontrol

Improvement within workshop


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FEATURES OF QUALITY CIRCLE

Smoothens the production, creates

confidence and trust among each other

Voluntary participating groups

Managements support

Involves task performance

Leads to continuous improvement

Instructed and informal teams


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OBJECTIVE OF QUALITY CIRCLE

Generating ideas

Motivate

Improve quality

Identifying and solving problems

Self development and mutual development.


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TECHNIQUES ADOPTED - QC

Brain storming

Cause and effect analysisherring bone or

fish bone diagramgraphic aid

Pareto diagrams

Control charts

Flow diagrams and process flow chart

Data or information collection


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STAGES OF ADOPTION - QC

1. Conduct general awareness programmes

2. Quality circles are formed in the requiredareas.( 810 employees)

3. First meetingleaders , facilitators ,choosen, steering committee formed

4. Problem identifiedsolutions andalternativesrecommended to mgt.

5. Suggestions and recommendationsstudied and implemented


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ADVANTAGES OF QC

Preventing and problem solving attitude

Promoted job involvement and sense of

participation

Improves quality and productivity

Inspires team work and develop creativity

and innovative spirit.

Achieve cost reduction

Develop job satisfaction


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QUALITY ASSURANCE

It is the assu rance given to customersthat

the purchased product to containing specified

characteristics and is fit for the intended

purpose. It is defined as the sys tem of pol ic ies,

pro cedures and guidel inesthat establishes

and maintains specified standards of productquality.


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STEPS FOR QUALITY ASSURANCE

Assurance of

Physical and chemical properties in a product

Fitness of the product for its intended use

Rated performance by the product


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ELEMENTS OF QA SYSTEM

Customer

prioritiesOrg. capacitiesQM objectives

EMPLOYEESInputs

Goods production

System

outputs

Service

Delivery

system

customers

Product quality specifications

QUALITY MONITORING

Data about

customer

preferences

Data about employeeExperience and skills


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TYPES OF INSPECTION

Process

Key point

Shop centralised

Final inspection and testing

Inspection, SQC, automated control

Inspection is the art of applying tests, preferably

by the aid of measuring appliances to observe whether

a given item or product is within the specified limits

of variability or not


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SQCprocess control

Settingup a process control system:

Choose the characteristic for process control

Choose the measurement method

Choose an appropriate sampling procedure

Choose the type of control chart

Calculate the control limits

Plot the data and analyse


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CONTROL CHART

Determines the process variability anddetects unusual variations

Ensures product quality level.

Warns, rectifies Information about selection of process &

setting of Tolerance Limits

Builds reputation through customerssatisfaction

Central limit theorem99.73% - 3 SD


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ACCEPTANCE SAMPLING It is the process of inferring the quality of a large

numbers of items ( a batch or lot) based on thequality of a small sample of the items.

For incoming and outgoing materials

Acceptable quality:no. of defectives items in thesample is less than or equal to the specifiednumber.

Average outgoing quality: the average no. ofdefects in a lot.

AOQ = AVERAGE NO. OF DEFECTIVES X 100/NO.

OF ITEMS IN LOT Average outgoing limitthe maximum quality

which can be passed on the average


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AVERAGE OUTGOING QUALITY

LEVEL

It is a measure of the average or expected %

of defective items that the producer would

ship to the consumer under varying

conditions of proportion defectives


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TYPES OF ACCEPTANCE SAMPLING

PLANS

Single sampling plan: nno. of items, acceptance numberc.

Defective > centire lot reject or inspected 100

% One sample selected, economical, easy, lower

cost

Double sampling plan:

Sample size n1: c2 reject,between c1 & c2,take second sample n2, n1+ n2 :total no. of defectives exceed c2 : reject.


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Multiple sampling plansequential

sampling plan:

Natural extension of double sampling plan

Sample size n1based on cut-off pointsto

continue with one or more sample

Choice of alternatives Smaller first samples

Difficult, higher overhead cost

Lower total inspection

Some risk of making wrong inference

Success depends on - randomness


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WORK STUDY

Method study: to study and standardise methods of

work for a job

Work measurement : to measure work content of a

job Both result in high productivity

Aim:to assist mgt. to use available :

human

and material (plant and equipment ) resources effectivelypredetermined objectives

Better ways of doing work and avoiding waste in all forms


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USES OF WORK STUDY

Manufacturing budget

Production plan

Personnel policies

Material planning


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OBJECTIVES OF METHOD STUDY

Better design of plant, buildings andequipment

Improved layout of factories and offices

Effective material handling Better working conditions & environment

Job satisfaction

High standards of safety and health Improved flow of work and reduced time span

Std


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Applications of method study

Standardisationprocedures and methods

Smooth flow of work

Effective handling

Better safety standards

Improved layout, design, working conditions,

achievement

Effective utilization

Reduce expenses


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STEPS IN METHOD STUDY

1. Select

2. Record

3. Examine

4.

Developbestmethod, mosteconomical, practical,effective

5. Installstandard

practice

6. Maintainregularchecks

WORKMEASUREMENT

Select

Record

Examine

Measure

define


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RECORDING TECHNIQUES

Chartsfor processes

Outline process chart ( principal operations and inspectionmake ready, putaway, do )

Flow process chart (of men, material or equipmentoperation(, inspection( , transport ( , delay (D) and storage( )

Two handed process charthands & limbs Multiple activity chartsimultaneousinterrelated activities of

operators/machine

SIMOSimultaneous motion cyclemovement of bodytherbligs

Timerecordsdiagrams and models Flow & string diagram

Two or three dimensional models

Cycle graphs or chrono cycle graphs


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SIMO

Based on film analysis

To record simultaneously on the common

time scale the therbligs/group of therbligs

performed by different parts of the body ofone or more workers


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FLOW DIAGRAM

Relative position of production machinery,

jigs, fixturesand marks the path followed by

men & materials


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STRING DIAGRAM

Model or a scale plan of the shop, in which

every machine or equipment is marked and a

peg/pin is truck by or in the area representing

the facility. A continous coloured thread/string traces

the path taken up by men or materials while

performing the operation


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CYCLE GRAPH

Micro-motion studygraphic technique

Small electric bulb attached to finger/other

&photographed by still camerapath of light


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CHRONO CYCLE GRAPH

Interrupter placed in electric circuit with the

bulbflashed quickly & off slowlypath of

lightdotted line with pear shaped

Space between the dotsspeed

Size and shapeacceleration/retardation

No.of dots


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MOTION STUDYpart of method

study

Formal engineering analysis of motions

performed to accomplish work

Motion or movement of limbs

Motion study consist of dividing work into themost fundamental elements possible;

studying these elements separately and in

relation to one another and from thesestudied elements when times, building

methods of least waste.


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TECHNIQUES AVAIBLABLE

WORK STUDY

1. Time study

2. Synthesis

3. Analytical estimating

4. Activity sampling

5. Predetermined motion time standards

(PMTS)


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1.TIME STUDY/STOP WATCH

STUDY

Work measurement technique which records

the times and working rate for the

constituents of a specified job performed

under certain conditions. and also analyses the data to ascertain the

time required to perform a job at a predefined

level.


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OBJECTIVES OF TIME STUDY

the quantity of human work -specified task

establish the std time - avg worker working at anormal pace

Basis of comparison

Set labour std

Determine std costs, requirements, basic/normaltime, no. of machineshandle

Balance the work

Basis for setting piece rate or incentive wages

Schedules, cycle time


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Types of allowances

Fixed allowances (personal needs and basic fatigue)

Relaxation allowancesrest,compensatory rest, fatigue

Variable allowances( stress & strain, environmental)

Policy allowance Process allowance5% of basic time

Special allowancepermanent/temporary

Interference allowance

Periodic activity allowance

contingency


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2. SYNTHESIS

Used where time study techniques can be

avoided.

Std time computed by adding various

elemental times- work Std datamade availablelibrary

Used for estimating labour timescost

estimates


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3. ANALYTICAL ESTIMATING

Determine the time values for jobs, having longand non-repetitive operations

Time values determined : synthetic data or pastexperience

PROCEDURE:1. Find out job detailsstd procedure,dimension

2. Break the job into its elements

3. Select time values from the std datasynthetic data

4.

Estimate the time valuespast knowledge or exp.5. Add the time3 , 4- total basic/normal time

6. Add the relaxation allowance

7. Add any other allowancesarrive std. time

4 ACT T SA P G /


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4.ACTIVITY SAMPLING /WORK

SAMPLING

Involves defining the state of working,

observing the job over time and computing

the portion of time the worker is working

Ratio delay/snap reading method ofobserving

Method of finding the ratio of delay and work

element to the total process time by randomobservations

Process, machines or workers

USES OF WORK SAMPLING


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USES OF WORK SAMPLING

TECHNIQUES

Estimate the percentage of a protracted timeperiod consumed by various activity states

Determine allowances

Nature of distribution of work activities Estimate the % of utilisation of

machines/equip

Indicate the usage

Bases for indirect labour time stds

Determine Std time

PROCEDURE FOR WORK


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PROCEDURE FOR WORK

SAMPLING STUDY

Identify the activities

Calculate the time proportion

Choose the derived accuracy while arriving at

study results

Calculate specific times for each

Recompute the required sample at least at 2

- 3 levels

5 PREDETERMINED MOTION TIME


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5. PREDETERMINED MOTION TIME

SYSTEM

Technique by which normal or basic times

are established for basic human motions and

these time values are used to build up the

time for a job at the defined level ofperformance

Observing or thinking

Types of PMTS: Methods time measurement (MTM)


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1. METHODS TIME MEASURMENT

Predetermined time values for basic motions

or therbligsTMU (time measurement units) 1 TMU = 10 power of -5 hr

2. Work factor:

basic motions which are modified elementsof difficultymovement slowermodifies

basic time value

3. Basic motion times (BMT)Times were derived from the laboratory

experiments -

PROCEDURE OF PMTS


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PROCEDURE OF PMTS

Observe the job or think it

Itemize the job elements

Record std for each motion units

Find the sum of the stds

Estimate the allowance :

Total sum is the predetermined time std for

the job.


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Total Quality Management

New Thinking About Quality

Old Quality is smallq New Quality is BigQ

About products About organisations

Technical Strategic

For inspectors For everyone

Led by experts Led by Management

High grade The appropriate grade

About control About improvement


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Principles of Total Quality

1. Focus on the customer (Both internal & external

2. Participation and Team work

3. Employee involvement and empowerment

4. Continuous improvement and learning.

Q li H bi


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Quality Habit


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Three Levels of Quality

1. Organisation level Meeting external customerrequirements

2. .Process level Meeting the needs of internal

customers3. Performer level (job level Meeting the requirements of

or task design level) accuracy, completeness innovation,

timeliness and cost.


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END OF UNIT III

QUALITY MOVEMENT IN INDIA


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QUALITY MOVEMENT IN INDIA

Heritagemonuments,handicrafts US, Japan1950s

1980SConsolidated, synergy by pioneering effortsof CII

Walter Shewartfather of SQC visited india for3mths (1947- 1948): initiated SQC

Dr. Edward Demingdeming cycle 1950s

Dr. Juran

Launch of TQM1980striggered movement inindia.

Quality Control in Production Management

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