INTERVIEW QUESTIONS WITH ANSWERS FOR FRESHERS AND EXPERIENCED PERSON - PART 1

IMPORTANT INTERVIEW QUESTIONS FOR FRESHERS / EXPERIENCED – MECHANICAL ENGINEERING (AUTOMOBILE ENGINEERING & GENERAL ENGINEERING)

HI, THIS ARTICLE IS ABOUT SOME QUESTIONS THAT MIGHT BE HELPFUL FOR YOU TO CLEAR AN INTERVIEW. THESE QUESTIONS CAN BE REFERRED TO BY FRESHER AS WELL AS EXPERIENCED MECHANICAL AUTOMOBILE ENGINEERS.

I AM SURE IF YOU WILL PREPARE BELOW QUESTIONS YOU WILL CLEAR YOUR INTERVIEW.

• WHAT IS SIX SIGMA
• WHAT IS JIT (JUST IN TIME) TECHNIQUE
• WHAT IS KAIZEN
• WHAT IS PLANT LAYOUT
• WHAT IS KANBAN
• WHAT IS REDBIN ANALYSIS TECHNIQUE
• WHAT IS PPAP (PRODUCTION PART APPROVAL PROCESS)
• WHAT IS APQP (ADVANCE PRODUCT QUALITY PLANNING)
• WHAT IS ORGANIZATION STRUCTURE
• WHAT IS MSA (MEASUREMENT SYSTEM ANALYSIS)
• WHAT IS SQC (STATISTICAL QUALITY CONTROL)
• WHAT IS FMEA (FAILURE MODE EVALUATION AND ANALYSIS)
• WHAT IS BATH TUB CURVE
• WHAT IS SMED (SINGLE MINUTE EXCHANGE OF DIE SET)
• WHAT IS VERNIER CALIPER, MICROMETER AND LEAST COUNT OF V.C. AND M.M
• WHAT IS SINE GAUGE AND HOW IT WORKS
• WHAT IS HEIGHT GAUGE AND HOW IT WORKS
• WHAT IS DIAL INDICATOR
• WHAT IS PPC (PRODUCTION PLANNING CONTROL)
• WHAT IS V-BLOCK AND HOW IT WORKS

QUE 1:- WHAT IS SIX SIGMA

SIX SIGMA IS A DISCIPLINED, DATA-DRIVEN APPROACH AND METHODOLOGY FOR ELIMINATING DEFECTS IN ANY PROCESS – FROM MANUFACTURING TO TRANSACTIONAL AND FROM PRODUCT TO SERVICE.

OR

SIX SIGMA IS A HIGHLY DISCIPLINED PROCESS THAT HELPS US FOCUS ON DEVELOPING AND DELIVERING NEAR-PERFECT PRODUCTS AND SERVICES.

OR

SIX SIGMA'S AIM IS TO ELIMINATE WASTE AND INEFFICIENCY, THEREBY INCREASING CUSTOMER SATISFACTION BY DELIVERING WHAT THE CUSTOMER IS EXPECTING.

LEVELS OF SIX SIGMA: -

SIGMA LEVEL	DPMO (DEFECTS PER MILLION OPPORTUNITIES)	PERCENT DEFECTIVE	PERCENTAGE YIELD
1	691,462	69%	31%
2	308,538	31%	69%
3	66,807	6.7%	93.3%
4	6,210	0.62%	99.38%
5	233	0.023%	99.997%
6	3.4	0.00034%	99.99966%
7	0.019	0.0000019%	99.9999981%

QUE 2: - WHAT IS JIT

JUST-IN-TIME (JIT) IS AN INVENTORY STRATEGY EMPLOYED BY THE COMAPNIES TO INCREASE EFFICIENCY AND DECREASE WASTE BY RECEIVING GOODS ONLY AS THEY ARE NEEDED IN THE PRODUCTION PROCESS, THEREBY REDUCING INVENTORY COSTS.

OR

JIT REFERS TO ZERO INVENTORY (MEANS NOT ZERO DAYS BUT TWO DAYS INVENTORY) OPERATION. IT IS CONTINUOUS PROCESS IT SEEKS ELIMINATING RAW MATERIAL STOCK AND FINISHED GOODS STOCK.

QUE 3: - WHAT IS KAIZEN

KAIZEN IS A JAPANESE WORD MEANING CONTINUOUS IMPROVEMENT. IT'S MADE UP OF TWO CHARACTERS IN JAPANESE: KAI, WHICH MEANS 'CHANGE,' AND ZEN, WHICH MEANS 'GOOD.' IT'S USED TO DESCRIBE A COMPANY CULTURE WHERE EVERYONE, FROM THE CHAIRMAN TO THE CLERK, REGULARLY EVALUATES HIS OR HER WORK AND THINKS OF WAYS TO IMPROVE IT. THE CONCEPT IS THAT SMALL STEPS ON A REGULAR BASIS WILL LEAD TO LARGE IMPROVEMENTS OVER TIME.

OR

KAIZEN (“CHANGE IS FOR GOOD”) ALSO KNOWN AS CONTINUOUS IMPROVEMENT, IS A LONG-TERM APPROACH TO WORK THAT SYSTEMATICALLY SEEKS TO ACHIEVE SMALL, INCREMENTAL CHANGES IN PROCESSES IN ORDER TO IMPROVE EFFICIENCY AND QUALITY

OR

KAIZEN (PRONOUNCED KI-ZEN) IS A JAPANESE WORD CONSTRUCTED FROM TWO IDEOGRAPHS, THE FIRST OF WHICH REPRESENTS CHANGE AND THE SECOND GOODNESS OR VIRTUE. KAIZEN IS COMMONLY USED TO INDICATE THE PROGRESSIVE LONG-TERM BETTERMENT OF SOMETHING OR SOMEONE (CONTINUOUS IMPROVEMENT) AS IN THE PHRASE SEIKATSU O KAIZEN SURU WHICH MEANS TO “BETTER ONE’S LIFE.” THE TERM KAIZEN IS USED IN THREE WAYS. THE FIRST USE IS CONSISTENT WITH ITS LITERAL MEANING. THE SECOND USE IS AS A COMPANYWIDE MANAGEMENT PROGRAM THAT ESTABLISHES A CULTURE FOCUSED ON CONTINUOUS IMPROVEMENT OF ALL PROCESSES AND WORK PLACES THROUGH THE ELIMINATION OF WASTE. THE THIRD USE IS AS THE LABEL FOR A GROUP OF METHODS THAT IMPROVE WORK PROCESSES.

QUE 4: - WHAT IS PLANT LAYOUT

PLANT LAYOUT IS THE MOST EFFECTIVE PHYSICAL ARRANGEMENT, EITHER EXISTING OR IN PLANS OF INDUSTRIAL FACILITIES I.E. ARRANGEMENT OF MACHINES, PROCESSING EQUIPMENT AND SERVICE DEPARTMENTS TO ACHIEVE GREATEST CO-ORDINATION AND EFFICIENCY OF 4 M'S (MEN, MATERIALS, MACHINES AND METHODS) IN A PLANT.

OR

PLANT LAYOUT REFERS TO THE PHYSICAL ARRANGEMENT OF PRODUCTION FACILITIES. IT IS THE CONFIGURATION OF DEPARTMENTS, WORK CENTRES AND EQUIPMENT IN THE CONVERSION PROCESS. IT IS A FLOOR PLAN OF THE PHYSICAL FACILITIES, WHICH ARE USED IN PRODUCTION.

THE OBJECTIVES OF PLANT LAYOUT ARE:

• STREAMLINE THE FLOW OF MATERIALS THROUGH THE PLANT.
• FACILITATE THE MANUFACTURING PROCESS.
• MAINTAIN HIGH TURNOVER OF IN-PROCESS INVENTORY.
• MINIMIZE MATERIALS HANDLING AND COST.
• EFFECTIVE UTILIZATION OF MEN, EQUIPMENT AND SPACE.
• FLEXIBILITY OF MANUFACTURING OPERATIONS AND ARRANGEMENTS.
• MINIMIZE INVESTMENT IN EQUIPMENT.
• MINIMIZE OVERALL PRODUCTION TIME.
• MAINTAIN FLEXIBILITY OF ARRANGEMENT AND OPERATION.

TYPES OF PLANT LAYOUT

• PRODUCT OR LINE LAYOUT - IF ALL THE PROCESSING EQUIPMENT AND MACHINES ARE ARRANGED ACCORDING TO THE SEQUENCE OF OPERATIONS OF THE PRODUCT, THE LAYOUT IS CALLED PRODUCT TYPE OF LAYOUT. IN THIS TYPE OF LAYOUT, ONLY ONE PRODUCT OF ONE TYPE OF PRODUCTS IS PRODUCED IN AN OPERATING AREA.
• PROCESS OR FUNCTIONAL LAYOUT - IN THIS TYPE OF LAYOUT, THE MACHINES AND NOT ARRANGED ACCORDING TO THE SEQUENCE OF OPERATIONS BUT ARE ARRANGED ACCORDING TO THE NATURE OR TYPE OF THE OPERATIONS. THIS LAYOUT IS COMMONLY SUITABLE FOR NON REPETITIVE JOBS.
• FIXED POSITION LAYOUT - IN THIS TYPE OF LAYOUT THE MAJOR COMPONENT REMAIN IN A FIXED LOCATION, OTHER MATERIALS, PARTS, TOOLS, MACHINERY, MAN POWER AND OTHER SUPPORTING EQUIPMENT’S ARE BROUGHT TO THIS LOCATION.
• COMBINATION TYPE OF LAYOUT - IF THE GOOD FEATURES OF ALL TYPES OF LAYOUTS ARE CONNECTED, A COMPROMISE SOLUTION CAN BE OBTAINED WHICH WILL BE MORE ECONOMICAL AND FLEXIBLE.

QUE 5: - WHAT IS KANBAN

A JAPANESE MANUFACTURING SYSTEM IN WHICH THE SUPPLY OF COMPONENTS IS REGULATED THROUGH THE USE OF AN INSTRUCTION CARD SENT ALONG THE PRODUCTION LINE.

OR

KANBAN, ALSO SPELT KAMBAN, IS A JAPANESE TERM FOR “SIGNBOARD” OR “BILLBOARD” THAT INDICATES “AVAILABLE CAPACITY (TO WORK)”. KANBAN IS A CONCEPT RELATED TO LEAN AND JUST-IN-TIME (JIT) PRODUCTION, WHERE IT IS USED AS A SCHEDULING SYSTEM THAT TELLS YOU WHAT TO PRODUCE, WHEN TO PRODUCE IT, AND HOW MUCH TO PRODUCE.

QUE 6: - WHAT IS REDBIN ANALYSIS TECHNIQUE

‘RED BINS’ ARE RED CONTAINERS IN FRONT OF EVERY PRODUCTION LINE IN WHICH OPERATORS CAN PUT DEFECTIVE PARTS. ON A REGULAR BASIS, AT A GIVEN HOUR, THE TEAM GATHERS AROUND THE ‘RED BIN’, ANALYZE DEFECTS AND SUGGEST QUALITY IMPROVEMENTS.

OR

IN SHORT, IT IS A PROCESS TO IMPROVE THE PART PRODUCTION WITH HIGH ACCURACY BY ELIMINATING THE WASTAGE’S, WITH THE HELP OF DIFFERENT TECHNIQUES WE FIND THE RIGHT ANSWER ‘WHY IT IS REJECTED’OF THE REJECTED PART.

QUE 7: - WHAT IS PPAP (PRODUCTION PART APPROVAL PROCESS

THE PRODUCTION PART APPROVAL PROCESS (PPAP) IS A STANDARDIZED PROCESS IN THE AUTOMOTIVE AND AEROSPACE INDUSTRIES THAT HELPS MANUFACTURERS AND SUPPLIERS COMMUNICATE AND APPROVE PRODUCTION DESIGNS AND PROCESSES BEFORE, DURING, AND AFTER MANUFACTURE.

OR

A SET OF STEPS FOLLOWED BY MANUFACTURERS AND SUPPLIERS TO MAKE SURE THAT SAFETY RISKS ARE REMOVED FROM EACH MANUFACTURED PART, BEFORE DISPATCHING.

QUE 8: - WHAT IS APQP (ADVANCE PRODUCT QUALITY PLANNING)

ADVANCED PRODUCT QUALITY PLANNING (OR APQP) IS A FRAMEWORK OF PROCEDURES AND TECHNIQUES USED TO DEVELOP PRODUCTS IN INDUSTRY, PARTICULARLY THE AUTOMOTIVE INDUSTRY. IT IS QUITE SIMILAR TO THE CONCEPT OF DESIGN FOR SIX SIGMA (DFSS).

OR

APQP OR ADVANCED PRODUCT QUALITY PLANNING IS A STRUCTURED METHOD OF DEFINING AND ESTABLISHING THE STEPS NECESSARY TO ENSURE THAT A PRODUCT SATISFIES THE CUSTOMER. EFFECTIVE PRODUCT QUALITY PLANNING DEPENDS ON A COMPANY'S TOP MANAGEMENT'S COMMITMENT TO THE EFFORT REQUIRED IN MEETING CUSTOMER SPECIFICATIONS.

QUE 9: - WHAT IS ORGANIZATION STRUCTURE

AN ORGANIZATIONAL STRUCTURE DEFINES HOW ACTIVITIES SUCH AS TASK ALLOCATION, COORDINATION AND SUPERVISION ARE DIRECTED TOWARD THE ACHIEVEMENT OF ORGANIZATIONAL AIMS.

OR

AN ORGANIZATION IS A GROUP OF PEOPLE WHO TOGETHER WORK TO ACHIEVE A COMMON GOAL. IN ORDER TO WORK TOGETHER EFFICIENTLY, THE GROUP MUST FIND THE BEST WAY TO ORGANIZE THE WORK THAT NEEDS TO BE DONE IN ORDER TO MEET THE GOALS OF THE ORGANIZATION. ORGANIZATIONAL STRUCTURE DEFINES HOW TASKS ARE DIVIDED, GROUPED, AND COORDINATED IN ORGANIZATIONS. EVERY ORGANIZATION HAS A STRUCTURE THAT CLARIFIES THE ROLES THAT ORGANIZATIONAL MEMBERS PERFORM, SO THAT EVERYONE UNDERSTANDS THEIR RESPONSIBILITIES TO THE GROUP.

QUE 10: - WHAT IS MSA (MEASUREMENT SYSTEM ANALYSIS)

MEASUREMENT SYSTEM ANALYSIS (MSA) IS AN EXPERIMENTAL AND MATHEMATICAL METHOD OF DETERMINING HOW MUCH THE VARIATION WITHIN THE MEASUREMENT PROCESS CONTRIBUTES TO OVERALL PROCESS VARIABILITY. 

OR

THE PURPOSE OF MEASUREMENT SYSTEM ANALYSIS IS TO QUALIFY A MEASUREMENT SYSTEM FOR USE BY QUANTIFYING ITS ACCURACY, PRECISION, AND STABILITY.

QUE 11: - WHAT IS SQC (STATISTICAL QUALITY CONTROL)

STATISTICAL QUALITY CONTROL REFERS TO THE USE OF STATISTICAL METHODS IN THE MONITORING AND MAINTAINING OF THE QUALITY OF PRODUCTS AND SERVICES. ONE METHOD, REFERRED TO AS ACCEPTANCE SAMPLING, CAN BE USED WHEN A DECISION MUST BE MADE TO ACCEPT OR REJECT A GROUP OF PARTS OR ITEMS BASED ON THE QUALITY FOUND IN A SAMPLE.

STATISTICS: 
STATISTICS MEANS THE GOOD AMOUNT OF DATA TO OBTAIN RELIABLE RESULTS. THE SCIENCE OF STATISTICS HANDLES THIS DATA IN ORDER TO DRAW CERTAIN CONCLUSIONS. ITS TECHNIQUES FIND EXTENSIVE APPLICATIONS IN QUALITY CONTROL, PRODUCTION PLANNING AND CONTROL, BUSINESS CHARTS, LINEAR PROGRAMMING ETC.

QUALITY: 
QUALITY IS A RELATIVE TERM AND IS GENERALLY EXPLAINED WITH REFERENCE TO THE END USE OF THE PRODUCT. QUALITY IS THUS DEFINED AS FITNESS FOR PURPOSE.

CONTROL: 
CONTROL IS A SYSTEM FOR MEASURING AND CHECKING OR INSPECTING A PHENOMENON. IT SUGGESTS WHEN TO INSPECT, HOW OFTEN TO INSPECT AND HOW MUCH TO INSPECT, HOW OFTEN TO INSPECT. CONTROL ASCERTAINS QUALITY CHARACTERISTICS OF AN ITEM, COMPARES THE SAME WITH PRESCRIBED QUALITY STANDARDS AND SEPARATES DEFECTIVE ITEM FROM NON-DEFECTIVE ONES.

OR

STATISTICAL QUALITY CONTROL (SQC) IS THE TERM USED TO DESCRIBE THE SET OF STATISTICAL TOOLS USED BY QUALITY PROFESSIONALS. SQC IS USED TO ANALYZE THE QUALITY PROBLEMS AND SOLVE THEM.

QUE 12: - WHAT IS FMEA (FAILURE MODE EVALUATION AND ANALYSIS)

FAILURE MODES AND EFFECTS ANALYSIS (FMEA) IS A STEP-BY-STEP APPROACH FOR IDENTIFYING ALL POSSIBLE FAILURES IN A DESIGN, A MANUFACTURING OR ASSEMBLY PROCESS, OR A PRODUCT OR SERVICE. “FAILURE MODES” MEANS THE WAYS, OR MODES, IN WHICH SOMETHING MIGHT FAIL. FMEA IS USED DURING DESIGN TO PREVENT FAILURES.

OR

FAILURE MODE AND EFFECTS ANALYSIS (FMEA) IS A STRUCTURED APPROACH TO DISCOVERING POTENTIAL FAILURES THAT MAY EXIST WITHIN THE DESIGN OF A PRODUCT OR PROCESS.

OR

FAILURE MODES ARE THE WAYS IN WHICH A PROCESS CAN FAIL. EFFECTS ARE THE WAYS THAT THESE FAILURES CAN LEAD TO WASTE, DEFECTS OR HARMFUL OUTCOMES FOR THE CUSTOMER. FAILURE MODE AND EFFECTS ANALYSIS IS DESIGNED TO IDENTIFY, PRIORITIZE AND LIMIT THESE FAILURE MODES.

THERE ARE TWO BROAD CATEGORIES OF FMEA, DESIGN FMEA (DFMEA) AND PROCESS FMEA (PFMEA).

DESIGN FMEA: -

·         DESIGN FMEA (DFMEA) EXPLORES THE POSSIBILITY OF PRODUCT MALFUNCTIONS, REDUCED PRODUCT LIFE, AND SAFETY AND REGULATORY CONCERNS DERIVED FROM:

·         MATERIAL PROPERTIES

·         GEOMETRY

·         TOLERANCES

·         INTERFACES WITH OTHER COMPONENTS AND/OR SYSTEMS

·         ENGINEERING NOISE: ENVIRONMENTS, USER PROFILE, DEGRADATION, SYSTEMS INTERACTIONS

PROCESS FMEA: -

PROCESS FMEA (PFMEA) DISCOVERS FAILURE THAT IMPACTS PRODUCT QUALITY, REDUCED RELIABILITY OF THE PROCESS, CUSTOMER DISSATISFACTION, AND SAFETY OR ENVIRONMENTAL HAZARDS DERIVED FROM:

·         HUMAN FACTORS

·         METHODS FOLLOWED WHILE PROCESSING

·         MATERIALS USED

·         MACHINES UTILIZED

·         MEASUREMENT SYSTEMS IMPACT ON ACCEPTANCE

·         ENVIRONMENT FACTORS ON PROCESS PERFORMANCE

QUE 13: - WHAT IS BATH TUB CURVE

BATHTUB CURVE IS A TERM PERTAINING TO QUALITY OF PRODUCTS OR RELIABILITY ENGINEERING. IT DESCRIBES ONE PARTICULAR FORM OF A HAZARD FUNCTION WHICH IS FURTHER DIVIDED INTO THREE SECTIONS AS FOLLOWS: 

THE FIRST SECTION OF HAZARD IS THE EARLY FAILURE HAZARD, WHERE THE HAZARD RATE IS VERY HIGH INITIALLY BUT GOES ON DECREASING STEEPLY WITH TIME AS THE DEFECTIVE PRODUCTS ARE IDENTIFIED.

THE SECOND SECTION HAS ALMOST A CONSTANT LEVEL OF HAZARD AS IT IS MAINLY DUE TO RANDOM ERRORS PRESENT IN THE PRODUCTS.

THE THIRD AND THE FINAL SECTION IS REFERRED TO AS THE WEAR-OUT ERROR WHERE THE HAZARD GOES ON INCREASING WITH TIME. IT IS MAINLY THE PERIOD AFTER THE DESIGN LIFETIME OF THE PRODUCT AND THUS THE INCREASE IN HAZARD.

OR

THE BATHTUB CURVE IS A TYPE OF MODEL DEMONSTRATING THE LIKELY FAILURE RATES OF TECHNOLOGIES AND PRODUCTS. OVER A CERTAIN PRODUCT LIFETIME, THE BATHTUB CURVE SHOWS HOW MANY UNITS MIGHT FAIL DURING ANY GIVEN PHASE OF A THREE-PART TIMELINE. THE FIRST DOWNWARD PORTION OF THE CURVE IS CALLED AN “INFANT MORTALITY” PHASE AND SHOWS HOW A NUMBER OF UNITS WOULD QUICKLY FAIL DUE TO DEFECTS OR OTHER ISSUES. THE SECOND PART OF THE CURVE IS THE “NORMAL LIFETIME” OR “USEFUL LIFETIME” SEGMENT WITH A LOW FAILURE RATE. THE THIRD PART IS AN END-OF-LIFE INCREASING FAILURE RATE. TOGETHER, THESE THREE SEGMENTS LOOK LIKE A BATHTUB WITH TWO STEEP EDGES AND A FLAT BOTTOM.

QUE 14: - WHAT IS SMED (SINGLE MINUTE EXCHANGE OF DIE SET)

SMED (SINGLE-MINUTE EXCHANGE OF DIES) IS A SYSTEM FOR DRAMATICALLY REDUCING THE TIME IT TAKES TO COMPLETE EQUIPMENT CHANGEOVERS. THE ESSENCE OF THE SMED SYSTEM IS TO CONVERT AS MANY CHANGEOVER STEPS AS POSSIBLE TO “EXTERNAL” (PERFORMED WHILE THE EQUIPMENT IS RUNNING), AND TO SIMPLIFY AND STREAMLINE THE REMAINING STEPS. THE NAME SINGLE-MINUTE EXCHANGE OF DIES COMES FROM THE GOAL OF REDUCING CHANGEOVER TIMES TO THE “SINGLE” DIGITS (I.E. LESS THAN 10 MINUTES).

OR

SINGLE MINUTE EXCHANGE OF DIE SET IS A PROCESS OF REDUCING CHANGEOVER (SETUP) TIME BY CLASSIFYING ELEMENTS AS INTERNAL OR EXTERNAL TO A MACHINE’S OPERATING TIME AND THEN CONVERTING THE INTERNAL ELEMENTS SO THEY CAN BE DONE EXTERNALLY (WHILE THE MACHINE CONTINUES TO OPERATE). THE GOAL IS TO REDUCE THE SETUP TIME FROM HOURS DOWN TO LESS THAN 10 MINUTES (9 MINUTES OR LESS, THUS THE SINGLE MINUTE CONCEPT).

QUE 15: - WHAT IS VERNIER CALIPER, MICROMETER AND LEAST COUNT OF V.C. AND M.M

THE VERNIER CALIPER IS A PRECISION INSTRUMENT THAT CAN BE USED TO MEASURE INTERNAL AND EXTERNAL DISTANCES EXTREMELY ACCURATELY. IT IS AN INSTRUMENT USED TO MEASURE INTERNAL AND EXTERNAL DIMENSIONS OF AN OBJECT WITH A GREAT ACCURACY. IT IS PROVIDED WITH INWARD JAWS AND OUTWARD JAWS TO FACILITATE THE MEASUREMENT. A SCREW CLAMP IS PROVIDED THAT CAN LOCK THE POSITION OF THE VERNIER SCALE, SO THAT THE INSTRUMENT CAN BE MOVED WITHOUT DISTURBING THE READING. A MANUALLY OPERATED VERNIER CALIPER HAS A MAIN SCALE (IN MILLIMETERS OR INCHES) AND A SLIDING VERNIER SCALE ATTACHED TO THE MOVABLE JAW. THE TERM "LEAST COUNT" IS USED TO DEFINE THE ACCURACY OF A VERNIER CALIPER. IT IS THE RATIO OF THE SMALLEST DIVISION ON THE MAIN SCALE TO THE TOTAL NUMBER OF DIVISIONS ON VERNIER SCALE. SO WHEN WE MEASURE A DIMENSION OF AN OBJECT USING A VERNIER CALIPER, THE FORMULA FOR FINAL DIMENSION IS,

FINAL DIMENSION = MAIN SCALE READING + (VERNIER SCALE READING X LEAST COUNT)

NOWADAYS, VERNIER CALIPERS WITH DIGITAL DISPLAYS OR DIAL GAUGES ARE AVAILABLE. THESE REDUCE THE COMPLEXITY OF CHOOSING THE COINCIDENCE OF MAIN SCALE AND VERNIER SCALE AND CALCULATING THE FINAL READING AS IN MANUALLY OPERATED VERNIER CALIPER. BUT DUE TO LESS COST, MANUALLY OPERATED VERNIER CALIPERS ARE MORE POPULAR.

OR

A VERNIER CALIPER IS A MEASURING INSTRUMENT WHICH CAN MAKE INSIDE, OUTSIDE, OR DEPTH MEASUREMENTS. THE VERNIER SCALE ON IT IS MARKED IN BOTH BRITISH IMPERIAL AND METRIC DIVISIONS. THE VERNIER SCALE HAS A STATIONARY SCALE AND A MOVABLE SCALE, IN THIS CASE THE VERNIER BAR TO THE VERNIER PLATE. THE LENGTH IS READ FROM THE VERNIER SCALE.

THE MOVABLE SCALE ON THE VERNIER CALIPER IS PARALLEL TO THE FIXED SCALE. THESE HIGH PRECISION MEASURING INSTRUMENTS ARE ABLE TO MEASURE OUTSIDE AND INSIDE DIAMETERS AND MOST WILL EVEN MEASURE DEPTH. THERE ARE BOTH IMPERIAL AND METRIC SCALES. THE MAIN SCALE OF THE CALIPER IS DIVIDED INTO 10 PARTS, EACH EQUAL TO 0.100 INCH. THE AREA BETWEEN THE 0.100 MARKS IS DIVIDED INTO FOUR. EACH OF THESE DIVISIONS IS EQUAL TO 0.025 INCHES.

THERE ARE 25 DIVISIONS ON THE VERNIER SCALE, EACH ONE REPRESENTING 0.001 INCH. MEASUREMENT READINGS ARE TAKEN BY COMBINING THE MAIN AND VERNIER SCALES. ONLY ONE DIVISION LINE ON THE MAIN SCALE WILL ALWAYS LINE UP WITH A LINE ON THE VERNIER SCALE. THIS IS THE BASIS TO ENSURE ACCURATE MEASUREMENTS.

TO READ THE CALIPER, LOCATE THE LINE ON THE MAIN SCALE THAT LINES UP WITH THE ZERO (0) ON THE VERNIER SCALE. IF THE ZERO LINED UP WITH THE 1 ON THE MAIN SCALE, THE READING WOULD BE 0.100 INCHES. IF THE ZERO ON THE VERNIER SCALE DOES NOT LINE UP EXACTLY WITH A LINE ON THE MAIN SCALE, THEN LOOK FOR A LINE ON THE VERNIER SCALE THAT DOES LINE UP WITH A LINE ON THE MAIN SCALE.

MICROMETER: -

A GAUGE WHICH MEASURES SMALL DISTANCES OR THICKNESSES BETWEEN ITS TWO FACES, ONE OF WHICH CAN BE MOVED AWAY FROM OR TOWARDS THE OTHER BY TURNING A SCREW WITH A FINE THREAD.

A VERNIER SCALE ON CALIPER MAY HAVE A LEAST COUNT OF 0.1 MM WHILE A MICROMETER MAY HAVE LEAST COUNT OF 0.01 MM.

QUE 16: - WHAT IS SINE GAUGE AND HOW IT WORKS

A SINE BAR CONSISTS OF A HARDENED, PRECISION GROUND BODY WITH TWO PRECISION GROUND CYLINDERS FIXED AT THE ENDS. THE DISTANCE BETWEEN THE CENTERS OF THE CYLINDERS IS PRECISELY CONTROLLED, AND THE TOP OF THE BAR IS PARALLEL TO A LINE THROUGH THE CENTERS OF THE TWO ROLLERS.

THE SINE PRINCIPLE USES THE RATIO OF THE LENGTH OF TWO SIDES OF A RIGHT TRIANGLE IN DERIVING A GIVEN ANGLE. IT MAY, BE NOTED THAT DEVICES OPERATING ON SINE PRINCIPLE ARE CAPABLE OF “SELF GENERATION”. THE MEASUREMENT IS USUALLY LIMITED TO 45° FROM LOSS OF ACCURACY POINT OF VIEW.

THE ACCURACY WITH WHICH THE SINE PRINCIPLE CAN BE PUT TO USE IS DEPENDENT IN PRACTICE, ON SOME FORM OF LINEAR MEASUREMENT. THE SINE BAR IN ITSELF IS NOT A COMPLETE MEASURING INSTRUMENT.

ANOTHER DATUM SUCH AS A SURFACE PLATE IS NEEDED, AS WELL AS OTHER AUXILIARY EQUIPMENT.

WORKING: -

• TO SET AN ANGLE OF ANY SINE DEVICE.WHETHER IT IS A SINE BAR, SINE PLATE, COMPOUND SINE PLATE, OR OTHER SINE TOOL, YOU MUST FIRST DETERMINE THE CENTER DISTANCE OF THE DEVICE AND THE ANGLE YOU WISH TO SET.
• NEXT, YOU MUST LOOK UP THE 'SETTING CONSTANT' IN THE APPROPRIATE TABLE.

THE SINE TABLES PROVIDED IN THIS BOOKLET ARE THE BASIC SIZES NEEDED TO SET AN ANGLE ON MOST SINE PRODUCTS. FOR CENTER DISTANCES OTHER THAN THOSE SIZES LISTED, USE THE APPROPRIATE MULTIPLE OF THE CONSTANT DETERMINED FROM THE BASIC CHART.

FOR EXAMPLE: TO OBTAIN THE CONSTANT NEEDED TO SET A 15 DEGREE 12 MINUTE ANGLE ON A 10" SINE PLATE, LOOK UP THE CONSTANT IN THE 5" CHART AND FIND 1.310946". MULTIPLY THIS BY 2 AND THE RESULT IS 2.621892"

• AFTER DETERMINING THE APPROPRIATE CONSTANT, ASSEMBLE A STACK OF GAUGE BLOCKS EQUAL IN SIZE TO THAT CONSTANT.
• PLACE THESE GAGE BLOCKS UNDER THE GAGE BLOCK ROLL OF THE SINE DEVICE, AND THE DESIRED ANGLE IS SET.
• TIGHTEN THE LOOKING MECHANISM ON THOSE DEVICES THAT HAVE ONE, AND YOU ARE READY TO GO.

QUE 17: - WHAT IS HEIGHT GAUGE AND HOW IT WORKS

A HEIGHT GAUGE IS A MEASURING DEVICE USED FOR DETERMINING THE HEIGHT OF OBJECTS.

OR

HEIGHT GAUGES MAY ALSO BE USED TO MEASURE THE HEIGHT OF AN OBJECT BY USING THE UNDERSIDE OF THE SCRIBER AS THE DATUM. THE DATUM MAY BE PERMANENTLY FIXED OR THE HEIGHT GAUGE MAY HAVE PROVISION TO ADJUST THE SCALE, THIS IS DONE BY SLIDING THE SCALE VERTICALLY ALONG THE BODY OF THE HEIGHT GAUGE BY TURNING A FINE FEED SCREW AT THE TOP OF THE GAUGE; THEN WITH THE SCRIBER SET TO THE SAME LEVEL AS THE BASE, THE SCALE CAN BE MATCHED TO IT. THIS ADJUSTMENT ALLOWS DIFFERENT SCRIBERS OR PROBES TO BE USED, AS WELL AS ADJUSTING FOR ANY ERRORS IN A DAMAGED OR RESHARPENED PROBE.

ACCURATE HEIGHT MEASUREMENT OF MACHINED COMPONENTS CAN BE DONE WITH A HEIGHT GAUGE PLACED ON A SURFACE PLATE. THE WORKING PRINCIPLE OF A HEIGHT GAUGE IS SIMILAR TO THE VERNIER CALIPER. IT IS AVAILABLE IN ALL THE THREE TYPES, I.E. WITH A CONVENTIONAL VERNIER SCALE OR DIAL GAUGE OR A DIGITAL DISPLAY. THE SURFACE PLATE IS A THICK SOLID GRANITE PLATE PLACED HORIZONTAL TO THE GROUND. A SHARP POINTED SCRIBER IS PROVIDED ON THE GAUGE TO MAKE A MARK ON THE OBJECT. THE OBJECT TO BE MEASURED FOR HEIGHT IS PLACED ON THE SURFACE PLATE. WITH THE HELP OF AN ADJUSTING SCREW, THE SCRIBER CAN BE MOVED UP AND DOWN.

QUE 18: - WHAT IS DIAL INDICATOR?

MEASUREMENT OF DEFLECTION IS NEEDED IN MANY INDUSTRIAL APPLICATIONS. EXAMPLES OF THIS INCLUDE MEASUREMENT OF THE MOVEMENT OF A CAR BODY WHILE TESTING IN BENDING MOMENTS AND CHECKING THE WAVINESS OF A SURFACE OF A MACHINED COMPONENT. IN BOTH CASES, SMALL LINEAR DISPLACEMENTS ARE TO BE MEASURED WITH ACCURACY. DIAL INDICATORS, MOUNTED ON MAGNETIC STAND PROVIDE ACCURATE MEASUREMENTS OF DEFLECTION FOR THE PARTS UNDER STUDY. THEY ARE ALSO AVAILABLE IN AN ELECTRONIC VERSION.

QUE 19: - WHAT IS PPC

PRODUCTION PLANNING IS AN ACTIVITY THAT IS PERFORMED BEFORE THE ACTUAL PRODUCTION PROCESS TAKES PLACE. IT INVOLVES DETERMINING THE SCHEDULE OF PRODUCTION, SEQUENCE OF OPERATIONS, ECONOMIC BATCH QUANTITIES, AND ALSO THE DISPATCHING PRIORITIES FOR SEQUENCING OF JOBS.

PRODUCTION CONTROL IS MAINLY INVOLVED IN IMPLEMENTING PRODUCTION SCHEDULES AND IS THE COROLLARY TO SHORT-TERM PRODUCTION PLANNING OR SCHEDULING. PRODUCTION CONTROL INCLUDES INITIATING PRODUCTION, DISPATCHING ITEMS, PROGRESSING AND THEN FINALLY REPORTING BACK TO PRODUCTION PLANNING. IN GENERAL TERMS, PRODUCTION PLANNING MEANS PLANNING OF THE WORK TO BE DONE LATER AND PRODUCTION CONTROL REFERS TO WORKING OUT OR THE IMPLEMENTATION OF THE PLAN.

QUE 20: - WHAT IS V-BLOCK AND HOW IT WORKS?

V-BLOCKS ARE PRECISION METALWORKING JIGS TYPICALLY USED TO HOLD ROUND METAL RODS OR PIPES FOR PERFORMING DRILLING OR MILLING OPERATIONS. THEY CONSIST OF A RECTANGULAR STEEL OR CAST IRON BLOCK WITH A 90-DEGREE CHANNEL ROTATED 45-DEGREES FROM THE SIDES, FORMING A V-SHAPED CHANNEL IN THE TOP.