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Chapter 6

Chapter 6. Process Selection and Facility Layout. Introduction. Process selection Deciding on the way production of goods or services will be organized Major implications Capacity planning Layout of facilities Equipment Design of work systems. Facilities and Equipment.

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Chapter 6

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  1. Chapter 6 Process Selection and Facility Layout

  2. Introduction • Process selection • Deciding on the way production of goods or services will be organized • Major implications • Capacity planning • Layout of facilities • Equipment • Design of work systems

  3. Facilities andEquipment CapacityPlanning Forecasting Layout Product andService Design ProcessSelection WorkDesign TechnologicalChange Process Selection and System Design

  4. Process Selection • Variety • How much • Flexibility • What degree • Volume • Expected output Batch Job Shop Repetitive Continuous

  5. Types of Operations Project/ Job Shop Unit or Batch Mass/ Assembly Continuous INCREASED VOLUME

  6. Process Design • Project Processes (Fixed Position) • Intermittent Flow Processes (Batch Shops) • Continuous Flow Processes (Flow Shops) • Processing Industries (Continuous)

  7. Job Shop (Fixed Position) • People and material move • Have limited duration • Small scale • Examples • Housing • Ship building • Dam • Appliance Repair

  8. Intermittent Flow Processes (Batch Shops) • No pattern exists between process of different products • Appropriate to service organizations • Moderate volume • Example: • Machine Shops • Auto Repair Shops • Commercial Bakery • Classroom Lecture

  9. Continuous Flow Processes (Flow Shops) • Sequences are the same (Standard Routes) • High volumes of standardized goods or services • Examples: • Assembly Lines • Car Wash

  10. Processing Industries (Continuous Flow) • One primary input (gas, wheat, etc) is converted to multiple outputs • Very high volumes of non-discrete goods • Example: • Petroleum • Chemicals • Food Industries

  11. Process Characteristics

  12. Process Characteristics

  13. Process Characteristics

  14. Automation • Automation: Machinery that has sensing and control devices that enables it to operate • Fixed automation • Programmable automation

  15. Automation • Computer-aided design and manufacturing systems (CAD/CAM) • Numerically controlled (NC) machines • Robot • Manufacturing cell • Flexible manufacturing systems(FMS) • Computer-integrated manufacturing (CIM)

  16. Functional Areas Being Linked to Manage the Flow of Information • Design • Handling of Materials • Storage and Retrieval of Information • Control of Machine Tools

  17. Design • CAD • No longer limited to the top, side and front views • Can observe the rotation of the part about any axis on the screen • Generally, improves productivity in the drafting room by a factor of 3 or more • At GM, the redesign of a single auto model requires 14 months instead of 24 months • The time needed to design custom values reduced from six months to one

  18. Handling of Materials • Data processing technology can be applied to the control of 3 general kids of machines in the factory: • Machines that store, retrieve, or transport materials • Machines that process the materials • Robots

  19. Handling of Materials • Automatic storage and retrieval systems transfer pallets of material into or out of storage rack up to 100 feet high • Mini Loaders • Hold drawers of small parts • Automatic Warehouse • Automatic shuttle takes the place of the fork-lift truck and its human operations

  20. Storage and Retrieval of Information • GT • The formation of part families based on design or manufacturing similarities (or both) • Classification of parts speed up the design of similar parts in the company • Only 20% of the parts actually need new design. 40% could be built from an existing design and the other 40% could be created by modifying an existing design. • Automatic guided vehicle

  21. Control of Machine Tools • NC • Machine tools run by programs • DNC • Direct numerically controlled machine tools • Several computerized, NC machine tools are linked by a hierarchy of computers

  22. Control of Machine Tools • FMS • Flexible Manufacturing System • It consists of an integrated collection of: • Automated Production Processes • NC • Robots • A material transport system • An automated transfer line • Robots

  23. Control of Robots • Robots • A programmable machine capable of moving materials and performing repetitive tasks. • Main features: • They are flexible • They eliminate the need for operators • Applications • Loading and unloading of machine tools • Jobs that are dirty, hazardous, unpleasant, or monotonous

  24. The Operating Capabilities of the Factory of the Future • Economic order quantity approaches 1 • Variety has no cost penalty (economy of slope) • Rapid response to changes in product design, market demand, and production mix • Unmanned and continuous operation is standard • Consistent high levels of quality and accuracy and repeatability introduce higher levels of certainty into the production planning and control activity

  25. Facilities Layout • Layout: the configuration of departments, work centers, and equipment, with particular emphasis on movement of work (customers or materials) through the system

  26. Importance of Layout Decisions • Requires substantial investments of money and effort • Involves long-term commitments • Has significant impact on cost and efficiency of short-term operations

  27. Basic Layout Types • Product layout • Layout that uses standardized processing operations to achieve smooth, rapid, high-volume flow • Process layout • Layout that can handle varied processing requirements • Fixed Position layout • Layout in which the product or project remains stationary, and workers, materials, and equipment are moved as needed

  28. Product Layout Raw materials or customer Station 2 Station 3 Station 4 Finished item Station 1 Material and/or labor Material and/or labor Material and/or labor Material and/or labor Used for Repetitive or Continuous Processing

  29. Advantages of Product Layout • High rate of output • Low unit cost • Labor specialization • Low material handling cost • High utilization of labor and equipment • Established routing and scheduling • Routing accounting and purchasing

  30. Disadvantages of Product Layout • Creates dull, repetitive jobs • Poorly skilled workers may not maintain equipment or quality of output • Fairly inflexible to changes in volume • Highly susceptible to shutdowns • Needs preventive maintenance • Individual incentive plans are impractical

  31. Assembly Line Balancing • Cycle time • The time required to produce one part is called the cycle time, or the maximum time allowed at any one work station • Assembly Line Balancing • Given a cycle time, find the minimum number of work stations or minimize the cycle time for a given number of work stations

  32. Assembly Line Balancing - Example

  33. Assembly Line Balancing

  34. Assembly Line Balancing CYCLE TIME .30 £ C £ 1.40 C = productive time/output rate C = (8hr x 60min)=.5 min 960 Number of work stations, N = total time/C N = 140 = 2.8 =3 .5

  35. Solution to Assembly Line Balancing Problem Station Tasks Assigned Total Task Time Idle Time 1 A, B 0.5 0 2 C, D 0.45 0.05 3 E, F 0.45 0.05 TOTAL 1.4 0.1

  36. Line Balancing Rules Some Heuristic (intuitive) Rules: • Assign tasks in order of most following tasks. • Count the number of tasks that follow • Assign tasks in order of greatest positional weight. • Positional weight is the sum of each task’s time and the times of all following tasks.

  37. Assembly Line Balancing Solution • Line Efficiency = Total Work Content C x N • Efficiency = 1.40 = .93 or 93% .5 x 3 • Balance Delay = 1 – efficiency = 1-.93 = 7%

  38. c d a b e f g h Example 2 0.2 0.2 0.3 0.8 0.6 1.0 0.4 0.3

  39. Station 1 Station 2 Station 3 Station 4 a b e g h f c d Solution to Example 2

  40. 1 2 3 4 In 5 Workers 6 Out 10 9 8 7 A U-Shaped Production Line

  41. Process Layout (functional) • Assume we have the following departments: • Accounting (A) • Production Planning (P) • Customer Service (C) • Sales (S) • What arrangement would be better?

  42. Used for Intermittent processing Job Shop or Batch

  43. Intermittent Process • Criteria • Desirability ranking • Volume of interaction • Cost of interaction • Distance • Time • Safety • Facility Limitations

  44. Advantages of Process Layouts • Can handle a variety of processing requirements • Not particularly vulnerable to equipment failures • Equipment used is less costly • Possible to use individual incentive plans

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