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Plant layout
Plant layout
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Plant layout

  1. 1. Department of Mechanical Engineering Dr Gaurang Joshi Unit no 2 Product / Process Planning and Design CAPM (01ME0721 )
  2. 2. Facility Layout  Layout refers to the configuration of departments, work centers, and equipment, with particular emphasis on movement of work (customers or materials) through the system.  Layout decisions are important for three basic reasons: 1. require substantial investments of money and effort; 2. involve long-term commitments, which makes mistakes difficult to overcome; and 3. have a significant impact on the cost and efficiency of operations
  3. 3. Factors affecting Plant Layout 1. Plant location and building 2. Nature of Product 3. Type of Industry 4. Plant Environment 5. Spatial Requirements 6. Repairs and Maintenance 7. Balance 8. Management Policy 9. Human Needs 10. Types of machinery and equipment
  4. 4. Factors affecting Plant Layout  The basic objective of layout design is to facilitate a smooth flow of work, material, and information through the system. Supporting objectives generally involve the following:  To facilitate attainment of product or service quality.  To use workers and space efficiently.  To avoid bottlenecks.  To minimize material handling costs.  To eliminate unnecessary movements of workers or materials.  To minimize production time or customer service time.  To design for safety.
  5. 5. Plant Layout : Types  The production process normally determines the type of plant layout to be applied to the facility: • Fixed position plant layout  Product stays and resources move to it. • Product oriented plant layout  Machinery and Materials are placed following the product path • Process oriented plant layout (Functional Layout).  Machinery is placed according to what they do and materials go to them. • Combined Layout  Combine aspects of both process and product layouts
  6. 6. Product oriented plant layout  This type of plant layout is useful when the production process is organized in a continuous or repetitive way.  Continuous flow : The correct operations flow is reached through the layout design and the equipment and machinery specifications.  Repetitive flow (assembly line): The correct operations flow will be based in a line balancing exercise, in order to avoid problems generated by bottle necks.  The plant layout will be based in allocating a machine as close as possible to the next one in line, in the correct sequence to manufacture the product.
  7. 7. Product Layouts Product layouts are used to achieve a smooth and rapid flow of large volumes of goods or customers through a system.
  8. 8. Product Layouts Disadvantages  Morale problems and to repetitive stress injuries.  Lack of maintaining equipment or quality of output.  Iinflexible for output or design  highly susceptible to shutdowns  A high utilization of labor and equipment  Preventive maintenance, the capacity for quick repairs, and spare-parts inventories are necessary expenses  Incentive plans tied to individual output are impractical Advantages  A high rate of output  Low unit cost due to high volume  Labor specialization  Low material-handling cost per unit  A high utilization of labor and equipment  The establishment of routing and scheduling in the initial design of the system  Fairly routine accounting, purchasing, and inventory control
  9. 9. Process Layouts  Process layouts are designed to process items or provide services that involve a variety of processing requirements.
  10. 10. Process oriented plant layout (Functional Layout)  This type of plant layout is useful when the production process is organized in batches.  Personnel and equipment to perform the same function are allocated in the same area.  The different items have to move from one area to another one, according to the sequence of operations previously established.  The variety of products to produce will lead to a diversity of flows through the facility.  The variations in the production volumes from one period to the next one (short periods of time) may lead to modifications in the manufactured quantities as well as the types of products to be produced.
  11. 11. Process Layout Advantages  Handle a variety of processing requirements  Not vulnerable to equipment failures  General-purpose equipment is less costly and is easier and less costly to maintain  Possible to use individual incentive systems Disadvantages  In-process inventory costs can be high  Routing and scheduling pose continual challenges  Equipment utilization rates are low  Material handling is slow and inefficient, and more costly per unit  Job complexities reduce the span of supervision and result higher supervisory costs  Special attention necessary for each product or customer and low volumes result in higher unit costs  Accounting, inventory control, and purchasing are much more involved
  12. 12. Fixed-Position Layouts  In fixed-position layouts, the item being worked on remains stationary, and workers, materials, and equipment are moved about as needed.  Fixed-position layouts are widely used in farming, firefighting, road building, home building, remodeling and repair, and drilling for oil. In each case, compelling reasons bring workers, materials, and equipment to the “product’s” location instead of the other way around.
  13. 13. Fixed-Position Layouts Ship Building yard
  14. 14. Fixed-Position Layouts Advantages  Saves time and cost in movement  Flexible as changes in job design can be easily incorporated  More economical when several orders in different stages are executed  Adjustments can be made to meet shortage of materials or absence of workers. Disadvantages • Production period being very long, capital investment is quite heavy • Very large space is required for storage of materials and equipment • As several operations are carried simultaneously, possibility of confusion and conflicts are high
  15. 15. Combination Layouts  Supermarket layouts are essentially process layouts, yet we find that most use fixed-path material-handling devices such as roller- type conveyors in the stockroom and belt-type conveyors at the cash registers.  Hospitals also use the basic process arrangement, although frequently patient care involves more of a fixed-position approach, in which nurses, doctors, medicines, and special equipment are brought to the patient.  Faulty parts made in a product layout may require off-line reworking, which involves customized processing. Moreover, conveyors are frequently observed in both farming and construction activities.  Cellular manufacturing - Group technology  Flexible manufacturing systems
  16. 16. Essentials of Ideal Layout 1. Principle of minimum movement 2. Principle of flow 3. Principle of space 4. Principle of safety 5. Principle of flexibility 6. Principle of interdependence 7. Principle of overall integration 8. Principle of minimum investment
  17. 17. Computerized Relative Allocation of Facilities Technique (CRAFT)/ or Computerized technique for relative allocation of facility Computerized Relative Allocation of Facilities Technique (CRAFT) is a tool that used to help improve the existing layout of the facilities. The facility is improved by swaping two or more departments to help arrange the facility to an optimal floor plan 1. CRAFT is more popular than the other computer based layout procedures. 2. It is improvement algorithm & starts with an initial layout & proceeds to improve the layout by interchanging the department’s pair wise to reduce the total material transportation cost. 3. It does not give the Optimal Layout; but the results are good & near optimal, which can be later corrected to suit the need of the layout planner.
  18. 18. Features of CRAFT 1.It attempts to minimize transportation cost, Where Transportation cost=flow × distance × unit cost It Requires assumptions that: (1) Move cost are independent of the equipment utilization & (2) Move costs are linearly related to the length of the move. 1. Distance matrix used is the rectilinear distance between department centroids 2. CRAFT being a path-oriented method, the final layout is dependent on the initial layout. Therefore, a number of initial layouts should be used as input to the CRAFT 3. CRAFT allows the use of dummy departments to represent fixed areas in the layout
  19. 19. Features of CRAFT CRAFT input requirements are as follows:  Initial Layout  Flow Data  Cost per unit distance  Total number of departments  Fixed departments & their location  Area of departments
  20. 20. CRAFT When will CRAFT be used?  CRAFT is used when the number of departments is enormous that the manual computation would be nearly impossible to do.  CRAFT is basically used with process layout approach, which also known as a functional layout that usually used in job shops or a batch production facility. What does the CRAFT do?  CRAFT do uses a pair wise exchange algorithm that may not return the optimal result because the final solution depends on the initial layout of the plant.  Rather than examine all the possible swaps, CRAFT considers the swap of only adjacent department pair or pairs that have the same area.
  21. 21. Steps of using CRAFT  Basic step of CRAFT has been modified a number of times, but we use COFAD (Tompkins and Reed, 1976) as a reference, a four step algorithm, tackles the selection of MHS and layout.  These are the following steps: 1. Determines an initial layout. 2. Selects an MHS for the layout obtained in the first step from a candidate list of equipment. 3. Calculates and revise the cost of each move based on material handling equipment to each move. (These three first step is repeated until a satisfactory solution obtained) To get a good- quality final solution, the user must provide different starting solution, evaluate the final solution obtained by CRAFT for each of these and choose the best one.
  22. 22. Advantages of CRAFT 1. The fact that the calculation is done by computer – sophisticated calculating machine – is clearly advantages that save a lot both time and money in the process. 2. It gives us rooms to define the variable and constraints that we have out here in the real world. 3. Flexibility can be seen as there are 6 buttons that can be utilized to generate series of different end solution
  23. 23. disadvantages of CRAFT 1. Inefficient 2. Jobs time occurred Jobs do not flow through in an orderly fashion, therefore backtracking occurs often. Idle time, more idle time may be experienced while workers are waiting for more work to arrive from different departments. 3. The (not) end result. End result may need to be modified, because once CRAFT has determined a solution it may need to be managed to create a layout that fits in the plant. 4. Greedy algorithm. It is the algorithm that always takes the best immediate solution. In contrary, a job shop that flow through the system is not always constant and causes fluctuations in the process.
  24. 24. Example of CRAFT Initial Layout Mid point/Centroids of departments
  25. 25. Calculation of centroids
  26. 26. Dept 1 2 3 4 5 6 7 8 1 0 18.5 8.5 2 0 16.5 3 0 14.5 4 8.5 8 0 11 5 0 4.5 6 14.5 10 4 0 7 0 8 8.5 8 0 Computing Inter department distances Distance measurement should be for department where we can have commuting Here 1-3,1-7,2-8,3-5,4-2,4- 7,5-8,6-1,6-3, 6-4,8-1,8-4
  27. 27. Dept. 1 2 3 4 5 6 7 8 1 0 18.5 8.5 2 0 16.5 3 0 14.5 4 8.5 8 0 11 5 0 4.5 6 14.5 10 4 0 7 0 8 8.5 8 0 F * C 1 2 3 4 5 6 7 8 1 0 20 2 2 0 1 3 0 2 4 1 0 2 5 0 1 6 10 5 4 0 7 0 8 2 8 0
  28. 28. Exchange 1 and 4 Exchange 1 and 3 Exchange 1 and 2
  29. 29. Dept. 1 2 3 4 5 6 7 8 1 0 7.5 11.5 2 0 16.5 3 0 14. 5 4 11.07 8 0 8.43 5 0 4.5 6 4 10 4 0 7 0 8 7.43 0
  30. 30. Dept. 1 2 3 4 5 6 7 8 1 0 7.5 11.5 2 0 16.5 3 0 14. 5 4 11.07 8 0 8.43 5 0 4.5 6 4 10 4 0 7 0 8 7.43 0 F * C 1 2 3 4 5 6 7 8 1 0 20 2 2 0 1 3 0 2 4 1 0 2 5 0 1 6 10 5 0 7 0 8 2 0
  31. 31. Problem 1 The present layout is shown in the figure. The manager of the company would like to interchange the department C and F. the handling frequencies (Cost per unit movement) between the department is given. Can we interchange the department ? Why? A F C E B D Dept. A B C D E F A 0 90 160 50 0 B 70 0 100 130 C 20 0 0 D 180 10 E 40 F
  32. 32. Solutions From/to A B C D E F A 1 1 2 2 3 B 2 1 3 2 C 1 1 2 D 2 1 E 1 F A F C E B D Distance between the department….assuming that there is no back tracking
  33. 33. Dept. A B C D E F A 0 90 160 50 0 B 70 0 100 130 C 20 0 0 D 180 10 E 40 F From/to A B C D E F A 1 1 2 2 3 B 2 1 3 2 C 1 1 2 D 2 1 E 1 F Dept . A B C D E F Tota l A 0 90 320 100 0 510 B 140 0 300 260 700 C 20 0 0 20 D 360 10 370 E 40 40 F Total 1640
  34. 34. A C F E B D From/to A B C D E F A 1 3 2 2 1 B 2 1 3 2 C 1 1 2 D 2 1 E 1 F Dept. A B C D E F A 0 90 160 50 0 B 70 0 100 130 C 20 0 0 D 180 10 E 40 F Dept . A B C D E F Tota l A 0 270 320 100 0 690 B 140 0 300 260 700 C 20 0 0 20 D 360 10 370 E 40 40 F Total 1820
  35. 35. Problem 2 The defense contractor is evaluating its machine shops current process layout. Figure shows the current process layout and the table shows the current trip matrix for the facilities. Health and safety regulation demanded fixed position of department E and F. Can we change the layout? If yes then propose the new one with resuced cost E D B F A C Dept. A B C D E F A 8 3 9 5 B 3 C 8 9 D 3 E 3 F
  36. 36. Solution Identify the maximum trip/traveling/handling frequency of any department with E and F department E D B F A C Dept. A B C D E F A 8 3 9 5 B 3 C 8 9 D 3 E 3 F
  37. 37. E D C F A B E D B F A C E D C F A B E D C F A B Dept. A B C D E F A 8 (3) 3 9 (2) 5 B 3 C 8 (1) 9 (1) D 3 E 3 F
  38. 38. E D B F A C E D C F A B Existing Plan Proposed Plan Departm ent pair No if trips Existing Layout Proposed Layout Distance Load (No of trips) * Distance Distance Load (No of trips) * Distance A-B 8 2 16 1 8 A-C 3 1 9 2 6 A-E 9 1 3 1 9 A-F 5 3 15 3 15 B-D 3 2 6 1 3 C-E 8 2 16 1 8 C-F 9 2 18 1 9 D-F 3 1 3 1 3 E-F 3 2 6 2 6 92 67
  39. 39. Problem 3 The defense contractor is evaluating its machine shops current process layout. Figure shows the current process layout and the table shows the current trip matrix for the facilities. Health and safety regulation demanded fixed position of department A. Can we change the layout? If yes then propose the new one with reduced cost E D B F A C Dept. A B C D E F A 4 3 16 2 10 B 3 C 8 9 D 8 8 E 3 F
  40. 40. Dept. A B C D E F A 4 (4) 3 (5) 16 (1) 2 10 (2) B 3 (5) C 8 (3) 9 (3) D 8 (4) 8 (4) E 3 (5) F E D B F A C F B C E A D F C B E A D
  41. 41. F B C E A D E D B F A C Departmen t pair No if trips Existing Layout Proposed Layout Distance Load (No of trips) * Distance Distance Load (No of trips) * Distance A-B 4 2 8 2 8 A-C 3 1 3 2 6 A-D 16 2 32 1 16 A-E 2 1 2 3 6 A-F 10 3 30 1 10 B-D 3 2 6 1 18 C-E 8 2 16 1 8 C-F 9 2 18 1 9 D-E 8 3 24 2 16 D-F 8 1 8 2 16 +6=1 19 E-F 3 2 6 =153 2
  42. 42. Problem 4 The defense contractor is evaluating its machine shops current process layout. Figure shows the current process layout and the table shows the current trip matrix for the facilities. Health and safety regulation demanded fixed position of department F & D. Can we change the layout? If yes then propose the new one with resuced cost E D B F A C Dept. A B C D E F A 4 3 16 2 10 B 3 C 8 9 D 8 8 E 3 F
  43. 43. E D C F B A Dept. A B C D E F A 4 3 16 (1) 2 10 (1) B 3 C 8 9(2) D 8 8 (3) E 3 F E D B F A C E D B F C A
  44. 44. E D C F B A E D B F A C Departmen t pair No if trips Existing Layout Proposed Layout Distance Load (No of trips) * Distance Distance Load (No of trips) * Distance A-B 4 2 8 1 4 A-C 3 1 3 1 3 A-D 16 2 32 1 16 A-E 2 1 2 2 4 A-F 10 3 30 2 20 B-D 3 2 6 2 6 C-E 8 2 16 1 8 C-F 9 2 18 1 9 D-E 8 3 24 3 24 D-F 8 1 8 1 8+6 108 E-F 3 2 6 =153 2
  45. 45. Thank you for your Kind Attention Dr Gaurang Joshi Assistant Professor Department of Mechanical engineering Marwadi University, Rajkot, Gujarat, India Email:- gaurang.joshi@marwadieducation.edu.in

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