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Chapter 6 Process Selection and Facility Layout.

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1 Chapter 6 Process Selection and Facility Layout

2 Introduction Process selection Major implications
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 Process Selection and System Design
Forecasting Product and Service Design Technological Change Capacity Planning Process Selection Facilities and Equipment Layout Work Design

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

5 Types of Operations INCREASED VOLUME 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
Project Intermittent Continuous PRODUCT Order Type Single Unit Batch Continuous or large batch Flow of Product None Jumbled Sequence Product Variety Very High High Low Market type Unique Custom Mass Volume Medium

12 Process Characteristics
Project Intermittent Continuous CAPITAL Inventory Medium High Low Equipment General Purpose Special Purpose LABOR Skills Task Type Non-routine Repetitive

13 Process Characteristics
Project Intermittent Continuous CONTROL Production Difficult Easy Quality Inventory EQUIPMENT General Purpose Special Purpose



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

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


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

20 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

21 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

22 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

23 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

24 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

25 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


27 Control of Robots Robots Main features: Applications
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



30 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

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

32 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

33 Basic Layout Types Product layout Process layout Fixed Position 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

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

35 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

36 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

37 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

38 Assembly Line Balancing - Example
Task Time (min) Immediate Predecessors A 0.2 ----- B 0.3 C D 0.25 E 0.15 B,C F D,E Total 1.4

39 Assembly Line Balancing

40 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

41 Solution to Assembly Line Balancing Problem
Station Tasks Assigned Total Task Time Idle Time 1 A, B 2 C, D 3 E, F TOTAL

42 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.

43 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 = = 7%

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

45 Solution to Example 2 a b e f d g h c Station 1 Station 2 Station 3

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

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

48 Used for Intermittent processing
Job Shop or Batch A P C S S C A P

49 Intermittent Process Criteria Desirability ranking
Volume of interaction Cost of interaction Distance Time Safety Facility Limitations

50 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

51 Disadvantages of Process Layouts
In-process inventory costs can be high Challenging routing and scheduling Equipment utilization rates are low Material handling slow and inefficient Complexities often reduce span of supervision Special attention for each product or customer Accounting and purchasing are more involved

52 Cellular Layouts Cellular Production Group Technology
Layout in which machines are grouped into a cell that can process items that have similar processing requirements Group Technology The grouping into part families of items with similar design or manufacturing characteristics

53 Process Layout - Example
Process Layout - work travels to dedicated process centers Milling Assembly & Test Grinding Drilling Plating

54 Functional Layout Gear cutting Mill Drill Lathes Grind Heat treat
Assembly 111 333 222 444 1111 2222 3333 44444 333333 22222

55 Cellular Manufacturing Layout – Group Technology
-1111 - 2222 Assembly - 3333 - 4444 Lathe Mill Drill Heat treat Gear cut Grind

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