Industrial Engineering - CELLULAR TYPE LAYOUT

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CELLULAR TYPE LAYOUT 

THIS TYPE OF LAYOUT IS BASED ON THE GROUPING OF PARTS TO FORM PRODUCT / PART FAMILIES. SIMILAR PARTS MAY BE GROUPED INTO FAMILIES BASED ON COMMON PROCESSING SEQUENCES, SHAPES, TOOLING REQUIREMENTS, AND SO ON. THE PROCESSING EQUIPMENT REQUIRED FOR A PARTICULAR PRODUCT FAMILY ARE GROUPED TOGETHER AND PLACED IN A MANUFACTURING CELL. THE CELLS BECOME, IN EFFECT, MINIATURE VERSIONS OF PRODUCT LAYOUTS. THE CELLS MAY HAVE MOVEMENTS OF PARTS BETWEEN MACHINES VIA CONVEYORS OR HAVE A FLOW LINE CONNECTED BY A CONVEYOR. THIS TYPE OF LAYOUT IS USED WHEN VARIOUS PRODUCTS HAVE TO BE PRODUCED IN MEDIUM TO LARGE QUANTITIES. A PICTORIAL REPRESENTATION OF A CELLULAR TYPE OF LAYOUT IS GIVEN IN FIGURE 4. THE ADVANTAGES AND DISADVANTAGES ARE GIVEN IN TABLE 4.

TABLE 4: ADVANTAGES AND DISADVANTAGES OF CELLULAR TYPE OF LAYOUT

ADVANTAGES
DISADVANTAGES
  • HIGHER MACHINE UTILIZATION
  • SMOOTHER FLOW LINES AND SHORTER TRAVEL DISTANCES ARE EXPECTED THAN FOR PROCESS LAYOUT
  • OFFERS SOME BENEFITS OF BOTH PRODUCT AND PROCESS TYPE OF LAYOUT BECAUSE IT IS A COMPROMISE BETWEEN THE TWO
  • ENCOURAGES CONSIDERATION OF GENERAL PURPOSE EQUIPMENT
  • GREATER LABOR SKILLS REQUIRED
  • FLOW BALANCE REQUIRED IN EACH CELL
  • HAS SOME OF THE DISADVANTAGES OF PRODUCT AND PROCESS TYPE OF LAYOUT; IT IS A COMPROMISE BETWEEN THE TWO



LAYOUT SELECTION:
THE BASIS OF SELECTION OF A LAYOUT IS THE VOLUME-VARIETY ANALYSIS. VOLUME-VARIETY ANALYSIS IS BASED ON THE PARETO'S PRINCIPLE, WHICH FOCUSES ON THE FACT THAT A MAJORITY OF THE RESOURCES ARE CONSUMED BY A SMALL FRACTION OF THE POPULATION. FOR EXAMPLE 85% OF THE WEALTH OF THE WORLD IS HELD BY 15% OF THE PEOPLE. THIS RULE ALSO APPLIES TO FACILITIES DESIGN I.E. 85% OF THE PRODUCTION VOLUME IS ATTRIBUTED TO 15% OF THE PRODUCT LINE. TO DECIDE A LAYOUT, A PART-POPULATION ANALYSIS MUST FIRST BE COMPLETED. A BAR CHART BETWEEN THE TYPE OF PRODUCTS AND THE QUANTITY TO BE PRODUCED IS DEVELOPED. THIS CHART IS ALSO CALLED PRODUCT-QUANTITY CHART (FIGURE 5) AND, BASED ON THIS CHART, DECISION REGARDING THE TYPE OF LAYOUT TO BE USED IS TAKEN. FOR THE PRODUCTS LYING IN THE AREA X (FIGURE 5) -A PRODUCT TYPE OF LAYOUT IS RECOMMENDED AND FOR THE PRODUCTS LYING IN THE AREA Y , A PROCESS TYPE OF LAYOUT IS RECOMMENDED. IN THE MIDDLE (AREA BETWEEN X AND Y ), A COMBINATION OF PRODUCT AND PROCESS TYPE LAYOUTS, IS RECOMMENDED (( MUTHER, R, SYSTEMATIC LAYOUT PLANNING, SECOND EDITION , CBI PUBLISHING COMPANY, INC. BOSTON, 1973 ). 

TYPES OF FLOW PATTERNS
IN THE FACILITIES LAYOUT PROBLEM, THE DECISION REGARDING PLACEMENT OF THE MACHINES IS TYPICALLY MADE. DEPENDING ON THE APPLICATION AND AVAILABILITY OF SPACE, THE MACHINES ARE PLACED IN ONE OF THE FOLLOWING PATTERN ( (( TOMPKINS, J. A., ET AL., FACILITY PLANNING, SECOND EDITION , JOHN WILEY & SONS, NY,1996)
  • STRAIGHT LINE PATTERN,
  • U-SHAPED PATTERN,
  • S-SHAPED PATTERN AND
  • W- SHAPED PATTERN
STRAIGHT LINE PATTERN
THE STRAIGHT-LINE PATTERN IS NORMALLY USED WHEN PRODUCTS ARE PRODUCED IN LARGE QUANTITIES AND THE NUMBER OF STEPS REQUIRED FOR THEIR PRODUCTION IS FEW. MOREOVER, THE SHIPPING AND RECEIVING SECTIONS ARE ON THE OPPOSITE SIDES.

U-SHAPED PATTERN
U-SHAPED PATTERNS ARE OFTEN USED WHEN IT IS NECESSARY TO KEEP THE BEGINNING (RECEIVING) AND END (SHIPPING) OF THE LINE AT THE SAME SIDE AND SAME END OF THE PLANT . U-SHAPED PATTERNS ARE ALSO PREFERRED IN JUST-IN-TIME LAYOUTS. WORKERS ARE GENERALLY PLACED IN THE CENTER OF THE U. FROM THERE THEY CAN MONITOR MORE THAN ONE MACHINE AT A TIME.

S-SHAPED PATTERN
S-SHAPED PATTERNS ARE USED FOR LONG ASSEMBLY PROCESSES THAT HAVE TO FIT IN THE SAME AREA AS WELL AS WHEN IT IS NECESSARY TO KEEP THE RECEIVING AND SHIPPING ENDS ON THE OPPOSITE SIDES.

W-SHAPED PATTERN
W-SHAPED PATTERN, LIKE THE S-SHAPED PATTERN IS ALSO USED FOR LONG ASSEMBLY PROCESSES, WHICH HAVE TO FIT IN THE SAME AREA. WHEN IT IS ALSO NECESSARY TO KEEP THE RECEIVING AND SHIPPING ENDS ON THE SAME SIDE, THE W-SHAPED PATTERN IS PREFERRED.

LAYOUT DESIGN PROCEDURE
THE MAJOR STEPS THAT NEEDED TO BE FOLLOWED IN THE LAYOUT DESIGN ARE :
  • STATEMENT OF THE PROBLEM IN TERMS OF ITS OBJECTIVE, SCOPE AND FACTORS TO BE CONSIDERED.
  • COLLECTION OF BASIC DATA ON SALES FORECAST, PRODUCTION VOLUME, PRODUCTION SCHEDULES, PART LISTS, OPERATIONS TO BE PERFORMED ETC.
  • CALCULATION OF PRODUCTION RATE AND EQUIPMENT REQUIREMENTS
  • DATA ANALYSIS AND ITS PRESENTATION IN THE FORM OF VARIOUS CHARTS .
  • CALCULATIONS OF SPACE REQUIREMENTS AND ALLOCATION OF ACTIVITY AREAS
  • DEVELOPMENT OF BLOCK PLAN, PLOT PLAN, AND DETAILED LAYOUT.
EVALUATION , SELECTION , AND INSTALLATION OF LAYOUT. 


REFERENCES : -    www.nptel.iitm.ac.in/

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