QUALITY MANAGEMENT

CIPET BHOPAL

WHAT IS QUALITY

“THE ABILITY OF YOUR PRODUCT OR SERVICE TO SATISFY YOUR CUSTOMERS.”

SEVEN QC TOOLS

THE SEVEN BASIC TOOLS OF QUALITY IS A DESIGNATION GIVEN TO A FIXED SET OF GRAPHICAL TECHNIQUES IDENTIFIED AS BEING MOST HELPFUL IN TROUBLESHOOTING ISSUES RELATED TO QUALITY. THIS TECHNIQUE IS USED TO SOLVE THE VAST MAJORITY OF QUALITY-RELATED ISSUES.

WHAT ARE SEVEN QC TOOLS

THEY ARE THE FOLLOWING SEVEN TOOLS.1.PARETO CHART2.CAUSE AND EFFECT DIAGRAM 3.CHECK SHEET4.FLOW CHART5.HISTOGRAM 6.SCATTER DIAGRAM7.CONTROL CHART

PARETO CHART

IN PARETO CHART, THE VERTICAL AXIS REPRESENTS PROPORTION, AND THE HORIZONTAL AXIS REPRESENTS ITEMS.BAR GRAPS REPRESENTING THE ITEMS ARE SORTED FROM THE LEFT IN DESCENDING ORDER IN TERMS OF THE VALUES. IN ADDITION, THE CUMULATIVE FREQUENCY DISTRIBUTION CURVE, A LINE CONNECTING THE CUMULATIVE PERCENTAGES UP TO EACH ITEMS) IS ALSO DRAWN. THE PURPOSE OF THE PARETO CHART IS TO HIGHLIGHT THE MOST IMPORTANT AMONG A (TYPICALLY LARGE) SET OF FACTORS. IN QUALITY CONTROL,

CAUSE AND EFFECT DIAGRAM

COMMON USES OF CAUSE AND EFFECT DIAGRAM ARE PRODUCT DESIGN AND QUALITY DEFECT PREVENTION. THE OTHER NAME IS FISHBONE DIAGRAM.

• PEOPLE: ANYONE INVOLVED WITH THE PROCESS• METHODS: HOW THE PROCESS IS PERFORMED AND THE

SPECIFIC REQUIREMENTS FOR DOING IT, SUCH AS POLICIES, PROCEDURES, RULES, REGULATIONS AND LAWS

• MACHINES: ANY EQUIPMENT, COMPUTERS, TOOLS, ETC. REQUIRED TO ACCOMPLISH THE JOB

• MATERIALS: RAW MATERIALS, PARTS, PENS, PAPER, ETC. USED TO PRODUCE THE FINAL PRODUCT

• MEASUREMENTS: DATA GENERATED FROM THE PROCESS THAT ARE USED TO EVALUATE ITS QUALITY

• ENVIRONMENT: THE CONDITIONS, SUCH AS LOCATION, TIME, TEMPERATURE, AND CULTURE IN WHICH THE PROCESS OPERATES

CAUSES ARE USUALLY GROUPED INTO MAJOR CATEGORIES TO IDENTIFY THESE SOURCES OF VARIATION. THE CATEGORIES TYPICALLY INCLUDE:

CAUSE AND EFFECT DIAGRAM

FLOW CHART

A FLOWCHART IS A TYPE OF DIAGRAM THAT REPRESENTS AN ALGORITHM, WORKFLOW OR PROCESS, SHOWING THE STEPS AS BOXES OF VARIOUS KINDS, AND THEIR ORDER BY CONNECTING THEM WITH ARROWS. FLOWCHARTS ARE USED IN ANALYZING, DESIGNING, DOCUMENTING OR MANAGING A PROCESS OR PROGRAM IN VARIOUS FIELDS

FLOW CHART

CHECK SHEET

• CHECK SHEET IS A TABLE THAT LISTS CHECK ITEMS TO FACILITATE INSPECTIONS.

CHECK SHEET

CHECK SHEETS TYPICALLY EMPLOY A HEADING THAT ANSWERS THE FIVE WS:• WHO FILLED OUT THE CHECK SHEET• WHAT WAS COLLECTED (WHAT EACH CHECK

REPRESENTS, AN IDENTIFYING BATCH OR LOT NUMBER)• WHERE THE COLLECTION TOOK PLACE (FACILITY, ROOM,

APPARATUS)• WHEN THE COLLECTION TOOK PLACE (HOUR, SHIFT, DAY

OF THE WEEK)• WHY THE DATA WERE COLLECTED

CHECK SHEET

HISTROGRAM

HISTROGRAM REPRESENTS THE DISTRIBUTION OF DATA BY USING BAR GRAPH. THE VERTICAL AXIS REPRESENTS THE FREQUENCY , AND THE HORIZONTAL AXIS REPRESENTS BINS OF DATA. IT IS ALSO CALLED A FREQUENCY DISTRIBUTION CHART. A HISTOGRAM IS A GRAPHICAL REPRESENTATION OF THE DISTRIBUTION OF DATA.

HISTROGRAM

SCATTER DIAGRAM

SCATTER DIAGRAM IS A DIAGRAM IN WHICH DATA OF TWO ITEMS ARE PLOTTED.

CONTROL CHARTS

CONTROL CHARTS SHOWN THE TREND OF AN ITEM AND INDICATES WHETHER THE ITEM IS UNDER CONTROL OR NOT. WE CAN CONCLUDE THAT THE ITEM IS UNDER CONTROL AS LONG AS THE VALUES STAY BETWEEN THE UPPER CONTROL LIMIT(UCL) AND LOWER CONTROL LIMIT(LCL), ALLOWING THE VARIANCE TO A CERTAIN EXTENT.

CONTROL CHART

QUALITY CIRCLE

A QUALITY CIRCLE IS A GROUP OF WORKERS WHO DO THE SAME OR SIMILAR WORK(USUALLY 3 TO 12 EMPLOYEES) WHO MEET REGULARLY TO IDENTIFY, ANALYZE AND SOLVE WORK-RELATED PROBLEMS. THESE MAY CONCERN QUALITY, PRODUCTIVITY, SAFETY, JOB STRUCTURE, PROCESS FLOW, CONTROL MECHANISM, AESTHETICS OF THE WORK AREA .

QUALITY CIRCLE

QUALITY CIRCLE IS A PARTICIPATIVE MANAGEMENT SYSTEM IN WHICH WORKERS MAKE SUGGESTIONS AND IMPROVEMENTS FOR THE BETTERMENT OF ORGANIZATIONS.

QUALITY CIRCLE

CONCEPT OF QUALITY CIRCLE

THE QC CONCEPT HAS THREE MAJOR ATTRIBUTES THESE ARE:

1- QC IS A FORM OF PARTICIPATIVE MANAGEMENT.

2- QC IS A HUMAN RESOURCE DEVELOPMENT TECHNIQUE.

3- QC IS A PROBLEM SOLVING TECHNIQUE.

CHARACTERISTICS OF QC

THE CHARACTERISTICS OF QC AS MANAGEMENT TOOL FOR IMPROVING PRODUCTIVITY AND QUALITY MAY BE LISTED AS BELOW:

1- QC ARE SMALL PRIMARY GROUPS OF EMPLOYEES/WORKERS WHOSE LOWER LIMIT IS 3 AND UPPER LIMIT IS 12.

QUALITY CIRCLE

2- THE MEMBERSHIPS OF QC ARE MOST VOLUNTORY. THE WORKERS/EMPLOYEES INTERESTED IN SOME AREA OF WORK IMPROVEMENT MAY COME TOGETHER TO FORM A CIRCLE.

3- EACH CIRCLE IS LED BY THE AREA SUPERVISOR. ALSO THEY ARE NORMALLY CO-ORDINATED CENTRALLY IN ORGANIZATION BY A PERSON WHO HAS BEEN TRAINED AS A FACILITATOR.

QUALITY CIRCLE

4-THE MEMBERS MEET REGULARLY EVERY WEEK OR ACCORDING TO AN AGREED SCHEDULE.

5- THE CIRCLE MEMBERS ARE SPECIALLY TRAINED IN TECHNIQUES OF ANALYSIS AND PROBLEM SOLVING IN ORDER TO PLAY THEIR ROLE EFFECTIVELY.

6- THE BASIC ROLE OF CIRCLE IS TO IDENTIFY AND SOLVE WORK RELATED PROBLEMS FOR IMPROVING QUALITY AND PRODUCTIVITY.

ADVANTAGE OF QC

1-PROMOTE HIGH LEVEL OF PRODUCTIVITY AND QUALITY MINDEDNESS.2-SELF AND MUTUAL DEVELOPMENT OF EMPLOYEES.3-CREATING TEAM SPIRIT AND UNITY OF ACTION.4-INCREASED MOTIVATION, JOB SATISFACTION AND PRIDE IN THEIR WORK.

ADVANTAGE OF QC

5- REDUCED ABSENTEESISM AND LABOUR TURNOVER.6-WASTE REDUCTION.7-COST REDUCTION.8-IMPROVED COMMUNICATION.9-SAFETY IMPROVEMENT.10-TRAINED STAFF.11-LEADERSHIP DEVELOPMENT.12-IDENTIFY WORK RELATED PROBLEM AND SOLVES THEM EFFECTIVELY

QUALITY MANAGEMENT

QM ENSURES THAT AN ORGANIZATION PRODUCT OR SERVICE IS CONSISTANT. IT HAS FOUR MAIN COMPONENTS:-1-QUALITY PLANNING2- QUALITY CONTROL3- QUALITY ASSURANCE4- QUALITY IMPROVEMENT

QUALITY MANAGEMENT

QUALITY MANAGEMENT IS FOCUSED NOT ONLY ON PRODUCT AND SERVICE QUALITY BUT ALSO ON TO MEANS TO ACHIEVE IT. QUALITY MANAGEMENT, THEREFORE USES QUALITY ASSURANCE AND CONTROL OF PROCESSES AS WELL AS PRODUCTS TO ACHIEVE MORE CONSISTENT QUALITY.

QUALITY MANAGEMENT

PDCAPDCA (PLAN–DO–CHECK–ACT OR PLAN–DO–CHECK–ADJUST) IS AN ITERATIVE FOUR-STEP PROBLEM SOLVING TYPICALLY USED IN QUALITY CONTROL. IT IS ALSO KNOWN AS DEMING CYCLE. IT IS FOUR-STEP MANAGEMENT METHOD USED IN BUSINESS FOR THE CONTROL AND CONTINUOUS IMPROVEMENT OF PROCESSES AND PRODUCTS. IT IS ALSO KNOWN AS THE DEMING CIRCLE.

PDCA CYCLE

PLAN DO

ACT CHECK

THE FOUR PHASES IN THE PLAN-DO-CHECK-ACT CYCLE INVOLVE:

PLAN: SET GOALS BASED ON CUSTOMER NEEDS.

DO: IMPLEMENT THE PLAN AND MEASURE ITS PERFORMANCE.

CHECK: ANALYZE WHAT HAPPENED

ACT: MAKE SURE IMPROVEMENT IS PERMANENT

BENEFITS OF THE PDCA CYCLE

1-PROBLEM SOLVING PROCESS2-CONTINUOUS IMPROVEMENT3-HUMAN RESOURCES DEVELOPMENT4-NEW PRODUCT DEVELOPMENT 5-PROCESS TRAILS6-PROJECT MANAGEMENT 7-DAILY ROUTINE MANAGEMENT FOR THE INDIVIDUAL AND OR THE TEAM

COST OF QUALITY

THE COSTS OF CARRYING OUT THE COMPANY QUALITY FUNCTIONS(MEETING THE QUALITY NEEDS OF THE CUSTOMERS) ARE KNOWN AS COSTS OF QUALITY. THESE INCLUDES:1- MARKET RESEARCH COSTS OF DISCOVERING THE QUALITY NEEDS OF THE CUSTOMERS.2-THE PRODUCT RESEARCH AND DEVELOPING COST.

COST OF QUALITY

3-THE DESIGN AND MANUFACTURING COST.4-COST OF INSPECTION AND TEST.5-COST OF DEFECT PREVENSION.6-COST OF SCRAP, QUALITY FAILURE.7-COST OF QUALITY ASSURANCE.

THE QUALITY COSTS BE DEFINED IN FOUR CATEGORIES:

1- COST OF PREVENTION2- COST OF APPRAISAL 3-COST OF INTERNAL FAILURES4-COST OF EXTERNAL FAILURES

COST OF QUALITY

COST OF QUALITY

COST OF PREVENTION

1- COST OF QUALITY PLANNING2- COST OF DOCUMENTING3- PROCESS CONTROL COST4- QUALITY EDUCATION AND TRANNING5- QUALITY IMPROVEMENT PROJECTS

COST OF APPRAISAL

• TEST AND INSPECTION OF PURCHASED MATERIALS

• ACCEPTANCE TESTING• CHECKING LABOR• SETUP FOR TEST OR INSPECTION• TEST AND INSPECTION EQUIPMENT• QUALITY AUDITS

COST OF INTERNAL FAILURE

• SCRAP• REWORK

COST OF EXTERNAL FAILURE

• COMPLAINTS IN WARRANTY• COMPLAINTS OUT OF WARRANTY• PRODUCT SERVICE• PRODUCT LIABILITY• PRODUCT RECALL• LOSS OF REPUTATION

QUALITY ASSURANCE

QUALITY ASSURANCE (QA) IS A WAY OF PREVENTING MISTAKES OR DEFECTS IN MANUFACTURED PRODUCTS AND AVOIDING PROBLEMS WHEN DELIVERING SOLUTIONS OR SERVICES TO CUSTOMERS. WHICH ISO 9000 DEFINES AS "PART OF QUALITY MANAGEMENT FOCUSED ON PROVIDING CONFIDENCE THAT QUALITY REQUIREMENTS WILL BE FULFILLED

QUALITY ASSURANCE

QUALITY ASSURANCE MEANS ENSURING CONFIRMETTING OF THE QUALITY TO THE REQUIRED BASIC SPECIFICATION OR GIVEN NEEDS. THE STAGE IN CONSIDERATION OF TOTAL QUALITY OF PRODUCT RELATED TO QUALITY ASSURANCE-

QUALITY ASSURANCE

1- DESIGN STAGE2-MANUFACTURING STAGE3-FIELD OBSERVATION

QUALITY ASSURANCE

1-DESIGN STAGE-TO ENSURE THAT THE QUALITY OF DESIGN IS ACCORDING TO THE NEEDS OF THE CUSTOMERS.

2-MANUFACTURING STAGE-TO CHECK WHETHER THE QUALITY OF PRODUCTS MANUFACTURED CONFORMS TO THE DESIGN SPECIFICATIONS.

QUALITY ASSURANCE

3-FIELD OBSERVATION- RELIABILITY AND PERFORMANCE ANALYSIS.

FUNCTION OF QUALITY ASSURANCE

1- PROCESSING OF FIELD COMPLAINTS.2- QUALITY RATING OF OUT GOING PRODUCTS.3- QUALITY SURVEY OR AUDIT.4-PREPARATION OF EXECUTIVE REPORT ON QUALITY.5- SETTING UP QUALITY LEVEL INSPECTION PLANNING.6- DISPOSITION OF NON- CONFIRMING PRODUCT.

ADVANTAGE OF QUALITY ASSURANCE

1- FEWER DEFECTS2- LESS SCRAP3- BETTER QUALITY4-GOOD CUSTOMER RELATION.5- HIGHER PRODUCTIVITY.6-LESS INSPECTION REFLECT.

6 SIGMA

SIX SIGMA IS A SET OF TECHNIQUES AND TOOLS FOR PROCESS IMPROVEMENT. IT WAS DEVELOPED BY MOTOROLA IN 1986.SIX SIGMA SEEKS TO IMPROVE THE QUALITY OF PROCESS OUTPUTS BY IDENTIFYING AND REMOVING THE CAUSES OF DEFECTS (ERRORS) AND MINIMIZING VARIABILITY IN MANUFACTURING AND BUSINESS PROCESSES. IT USES A SET OF QUALITY MANAGEMENT METHODS.

6 SIGMA

EACH SIX SIGMA PROJECT CARRIED OUT WITHIN AN ORGANIZATION FOLLOWS A DEFINED SEQUENCE OF STEPS AND HAS QUANTIFIED VALUE TARGETS, FOR EXAMPLE REDUCE PROCESS CYCLETIME, REDUCE POLLUTION, REDUCE COSTS, INCREASE CUSTOMER SATISFACTION AND INCREASE PROFIT.

6 SIGMA

THERE ARE TWO SIX SIGMA PROCESSES-1-DMAIC PROCESS2-DMADV PROCESS

DMAIC PROCESS

DMAIC IS USED FOR PROJECTS AIMED AT IMPROVING AN EXISTING BUSINESS PROCESSES.

DMAIC PROCESS

DMAIC PROCESS

THE DMAIC PROJECT METHODOLOGY HAS FIVE PHASES:1-DEFINE- * DEFINE THE PROJECT PURPOSE AND SCOPE.*IDENTIFY HIGH LEVEL PROCESSES FOR IMPROVEMENT.* DETERMINE CUSTOMER NEEDS AND BENEFITS.

DMAIC PROCESS

2-MEASURE- *IDENTIFY THE GAP BETWEEN CURRENT AND REQUIRED PERFORMANCE.*IDENTIFY POTENTIAL AREAS FOR IMPROVEMENTS.*PINPOINT PROBLEMS LOCATIONS AND OCCURRENCES.

DMAIC PROCESS

3-ANALYZE-• IDENTIFY ROOT CAUSES AND VALIDATE ROOT

CAUSES AGAINST CAPTURED DATA.• DETERMINE IMPROVEMENTS THAT NEEDS TO

BE MADE.

DMAIC PROCESS

4-IMPROVE- IMPROVE OR OPTIMIZE THE CURRENT PROCESS BASED UPON DATA ANALYSIS USING TECHNIQUES SUCH AS DESIGN OF EXPERIMENTS, POKA YOKE OR MISTAKE PROOFING.

DMAIC PROCESS

5-CONTROL-• PERFORM BEFORE AND AFTER ANALYSIS. • DOCUMENTS RESULTS AND DETERMINE NEXT

STEP RECOMMENDATIONS.

DMADV PROCESS

DMADV IS USED FOR NEW PROJECTS OR NEW BUSINESS PROCESS.

DMADV PROCESS

DMADV PROCESS

THE DMAIC PROJECT METHODOLOGY HAS FIVE PHASES:1-DEFINE- DEFINE THE PROJECT GOAL AND CUSTOMER( INTERNAL AND EXTERNAL DELIVERABLES.2-MEASURE- MEASURE AND DETERMINE CUSTOMER NEEDS AND SPECIFICATIONS.

DMADV PROCESS

3-ANALYZE- ANALYZE THE PROCESS OPTIONS TO MEET THE CUSTOMER NEEDS.

4-DESIGN- DESIGN THE PROCESS TO MEET THE CUSTOMER NEEDS.

5-VERIFY- VERIFY THE DESIGN PERFORMANCE AND ABILITY TO MEET CUSTOMER NEEDS.

JIT(JUST-IN-TIME)

J-I-T IS AN APPROACH THAT SEEKS TO ELIMINATES ALL SOURCES OF WASTE IN PRODUCTION ACTIVITIES BY PROVIDING THE RIGHT PART AT RIGHT PLACE AT THE RIGHT TIME

BENEFITS OF JIT

1-REDUCTION IN INVENTORY2-IMPROVED QUALITY3-REDUCED SPACE REQUIREMENTS4-SHORTER LEAD TIMES5-LOWER PRODUCTION COSTS6-INCREASED PRODUCTIVITY7-INCREASED MACHINE UTILIZATION8-GREATER FLEXIBILITY

POKA-YOKE‘POKA’ : MISTAKE ‘YOKE’ : PROOFING

• A POKA-YOKE IS ANY MECHANISM IN A LEAN MANUFACTURING PROCESS THAT HEALPS AN EQUIPMENT, OPERATOR AVOID(YOKE) MISTAKES(POKA).

• ITS PURPOSE IS TO ELIMINATE PRODUCT DEFECTS BY PREVENTING, CORRECTING AND DRAWING ATTENTION TO HUMAN ERRORS AS THEY OCCUR.

POKA-YOKE

• THE CONCEPT WAS FORMALIZED AND THE TERM ADOPTED BY SHIGEO SHINGO(JAPANESE INDUSTRIAL ENGINEER) AS PART OF THE TOYOTA PRODUCTION SYSTEM.

POKA-YOKE

• THIS TOOL CAN BE APPLIED TO ANY PROCESS, BE IT IN MANUFACTURING OR THE SERVICE INDUSTRY.

POKA-YOKE

BENEFITS OF POKA-YOKE• ELIMINATION OF SET-UP ERRORS AND IMPROVED

QUALITY • DECREASED SET-UP TIMES WITH ASSOCIATED

REDUCTION IN PRODUCTION TIME AND IMPROVED PRODUCTION CAPACITY

• SIMPLIFIED AND IMPROVED HOUSEKEEPING• INCREASED SAFETY• LOWER COSTS• LOWER SKILL REQUIREMENTS• INCREASED PRODUCTION FLEXIBILITY• IMPROVED OPERATOR ATTITUDES.

THE 5S SYSTEM

5S IS A BASIC, FUNDAMENTAL, SYSTEMATIC APPROACH FOR PRODUCTIVITY, QUALITY AND SAFETY IMPROVEMENT IN ALL TYPES OF BUSINESS. THE 5S ARE:-1-SORT2-SET IN ORDER3-SHINE4-STANDARIZE5-SUSTAIN

THE 5S SYSTEM1-SORT- ELIMINATE UNNECESSARY ITEMS FROM THE WORKPLACE.

2-SET IN ORDER- ARRANGE ITEMS SO THAT THEY ARE EASY TO USE, FIND AND PUT AWAY.

3-SHINE- KEEP THE ITEMS AND WORK AREA NEAT AND CLEAN.

4-STANDARDIZE- CREATE A CONSISTENT APPROACH TO TASKS AND PROCEDURES. 5-SUSTAIN- MAKE A HABIT OF MAINTAINING THE CORRECT PROCEDURE.

SAMPLING PLANS

SAMPLING PLANS MAY BE GROUPED INTO THREE CATEGORIES:-1-SINGLE SAMPLING PLAN2-DOUBLE SAMPLING PLAN 3-MULTIPLE SAMPLING PLAN

SINGLE SAMPLING PLAN

WHEN A DECISION ON ACCEPTANCE OR REJECTION OF THE LOT IS MADE ON THE BASIS OF ONLY ONE SAMPLE, THE ACCEPTANCE PLAN IS KNOWN AS A SINGLE SAMPLING PLAN. IN A SINGLE SAMPLING PLAN THREE NUMBERS ARE SPECIFIED.

SINGLE SAMPLING PLAN

N= LOT SIZE, FROM WHICH THE SAMPLE IS DRAWN.

n= SAMPLE SIZE

c= acceptance number

SINGLE SAMPLING PLAN

IF A SAMPLING PLAN IS

N = 50

n = 5

c = 1

SINGLE SAMPLING PLAN

IT MEANS, TAKE A SAMPLE OF 5 ITEMS FROM A LOT OF 50, IF THE SAMPLE CONTAINS MORE THAN 1 DEFECTIVE REJECT THE LOT, OTHERWISE ACCEPT THE LOT.

SINGLE SAMPLING PLAN

INSPECT A SAMPLE OF n PIECES IF NUMBER OF DEFECTIVES DOES NOT EXCEED ‘c’ EXCEED ‘c’ ACCEPT THE LOT REJECT THE LOT

DOUBLE SAMPLING PLAN

IN DOUBLE SAMPLING PLAN, HE DECISION ON ACCEPTANCE OR REJECTION AT ONCE IF THE FIRST SAMPLE IS GOOD ENOUGH OR REJECTED AT ONCE IF THE FIRST SAMPLE IS BAD ENOUGH. IF THE FIRST SAMPLE IS NEITHER GOOD ENOUGH NOR BAD ENOUGH, THE DECISION IS BASED ON THE EVIDENCE OF FIRST AND SECOND SAMPLE COMBINED.

DOUBLE SAMPLING PLAN

PARAMETERS:- n1 = NUMBER OF PIECES IN THE FIRST SAMPLE. c1 = ACCEPTANCE NUMBER FOR THE FIRST SAMPLE i.e. THE MAX NUMBER OF DEFECTIVES THAT WILL PERMIT THE ACCEPTANCE OF THE LOT ON THE BASIS OF THE FIRST SAMPLE.

DOUBLE SAMPLING PLAN

n2 = NUMBER OF PIECES IN THE SECOND SAMPLE.

n1+n2 = NUMBER OF SAMPLE IN THE TWO SAMPLES COMBINED.

c2 = ACCEPTANCE NUMBER OF THE TWO SAMPLES COMBINED.

DOUBLE SAMPLING PLAN

i.e. THE MAX NUMBER OF DEFECTIVES THAT WILL PERMIT THE ACCEPTANCE OF THE LOT ON THE BASIS OF THE FIRST AND SECOND COMBINED.

DOUBLE SAMPLING PLAN INSPECT n1 PIECES ZZ IF THE NO. OF DEFECTIVES DOES NOT EXCEED c1 c2<def.<_c1 EXCEEDS c2 ACCEPT THE LOT TAKE SECOND SAMPLE REJECT THE LOT OF n2 PIECES

DOUBLE SAMPLING PLAN

NO. OF DEFECTIVES IN THE FIRST AND SECOND SAMPLES COMBINED i.e. IN (n1+n2)

DOES NOT EXCEED c2 EXCEED c2 ACCEPT THE LOT REJECT THE LOT