Presentation Transcript

1. FACILITY AND WORK DESIGN CHAPTER 8 DAVID A. COLLIER AND JAMES R. EVANS
2. 8-1Describe four layout patterns and when they should be used. 8-2Explain how to design product layouts using assembly line balancing. 8-3Explain the concepts of process layout. 8-4Describe issues related to workplace design. 8-5Describe the human issues related to workplace design.
3. Vytec (www.vytec.com) is a leading manufacturer of vinyl siding for homes and businesses. Vytec makes 50 different product lines (called profiles) of siding, soffits, and accessories. Each profile is typically produced in 15 colors, creating 750 stock-keeping units. The finished siding is packaged in a carton that holds 20 pieces that is usually 12 feet long. The cartons are stacked in steel racks (called beds). Each bed holds 30 to 60 cartons, depending on the bed’s location in the warehouse. Vytec’s main warehouse is more than 200,000 square feet.
4. Chapter Introduction (continued) Over time, demand for each siding profile changes, and some are added and some are discontinued. One problem the warehouse faces periodically is the need to redo the location and capacity of beds in the warehouse. Using basic layout principles, high-demand siding profiles are located closest to the shipping dock to minimize travel and order-picking time. Although management would like to find a permanent solution to this stock placement problem in the warehouse, the continuous changes in demand and product mix necessitate a new design every few years.
5. What do youthink? Think of a facility in which you have conducted business—for instance, a restaurant, bank, or automobile dealership. How did the physical environment and layout enhance or degrade your customer experience?
6. Facility Layout Facility layout refers to the specific arrangement of physical facilities. Facility-layout studies are necessary whenever: a new facility is constructed, there is a significant change in demand or throughput volume, a new good or service is introduced to the customer benefit package, or different processes, equipment, and/or technology are installed.
7. Facility Layout Purposes of layout studies are to: minimize delays in materials handling and customer movement. maintain flexibility. use labor and space effectively. promote high employee morale and customer satisfaction. provide for good housekeeping and maintenance. enhance sales as appropriate in manufacturing and service facilities.
8. Facility Layout A product layout is an arrangement based on the sequence of operations that are performed during the manufacturing of a good or delivery of a service. Examples: Winemaking industry, credit card processing, Subway sandwich shops, paper manufacturers, insurance policy processing, and automobile assembly lines.
9. Exhibit 8.1 Product Layout for a Wine Manufacturer
10. Facility Layout Product Layout Advantages: Lower work-in-process inventories, shorter processing times, less material handling, lower labor skills, and simple planning and control systems. Disadvantages: A breakdown at one workstation can cause the entire process to shut down; a change in product design or the introduction of new products may require major changes in the layout, limiting flexibility.
11. Facility Layout A process layout consists of a functional grouping of equipment or activities that do similar work. Examples: Legal offices, shoe manufacturing, jet engine turbine blades, and hospitals use a process layout.
12. Exhibit 8.2 Process Layout for a Machine Shop
13. Facility Layout Process Layout Advantages: A lower investment in equipment, the diversity of jobs inherent in a process layout can lead to increased worker satisfaction. Disadvantages: High movement and transportation costs, more complicated planning and control systems, longer total processing time, higher in-process inventory or waiting time, and higher worker-skill requirements.
14. Facility Layout In a cellular layout, the design is not according to the functional characteristics of equipment, but rather by self-contained groups of equipment (called cells), needed for producing a particular set of goods or services. Examples: Legal services such as labor law, bankruptcy, divorce; medical specialties such as maternity, oncology, surgery.
15. Exhibit 8.3 Cellular Manufacturing Layout
16. Facility Layout Cellular Layout Advantages: Reduced materials-handling requirements, quicker response to quality problems, more efficient use of floor space, more worker responsibility increasing morale. Disadvantages: Duplication of equipment among cells, greater worker skills requirements.
17. Facility Layout A fixed-position layout consolidates the resources necessary to manufacture a good or deliver a service, such as people, materials, and equipment, in one physical location. Examples: The production of large items such as heavy machine tools, airplanes, buildings, locomotives, and ships. Service-providing examples include major hardware and software installations, sporting events, and concerts.
18. Fixed-Position Layout Advantages: Work remains stationary, reducing movement. Disadvantages: High level of planning and control required.
19. Exhibit 8.4 Comparison of Basic Layout Patterns
20. Facility Layout in Service Organizations Service organizations use product, process, cellular, and fixed-position layouts to organize different types of work. Process Layout—Services that need the ability to provide a wide variety of services to customers with differing requirements usually use a process layout. Examples: Libraries, hospitals, insurance companies Product Layout—Service organizations that provide highly standardized services tend to use product layouts. Examples: Restaurant kitchens
21. Exhibit 8.5 Product Layout for a Pizza Kitchen
22. Designing Product Layouts Product layouts in flow shops generally consist of a fixed sequence of workstations separated by buffers (queues of work-in-process). Flow-blocking delay occurs when a work center completes a unit but cannot release it because the in-process storage at the next stage is full. The worker must remain idle until storage space becomes available. Lack-of-work delayoccurs whenever one stage completes work and no units from the previous stage are awaiting processing.
23. Exhibit 8.6 A Typical Manufacturing Workstation Layout
24. Designing Product Layouts An assembly line isa product layout dedicated to combining the components of a good or service that has been created previously. Examples: Automobile assembly, Subway sandwich shops, insurance policy processing Assembly line balancing is a technique to group tasks among workstations so that each workstation has—in the ideal case—the same amount of work.
25. Assembly-Line Balancing Required information: The set of tasks to be performed and the time required to perform each task. 2. The precedence relations among the tasks—that is, the sequence in which tasks must be performed. 3. The desired output rate or forecast of demand for the assembly line.
26. Exhibit 8.7 A Three-Task Assembly Line One workstation: In an eight-hour day, could produce (1 part/1.0 min)(60 minutes per hour)(8 hours per day) = 480 parts/day Three workstation s (one for each task): The first operator can produce 120 parts per hour, or 960 parts/day. The second could produce 1,600 parts/day. The third operator can produce 2,400 parts/day. Maximum output is 960 parts/day. Two workstations (A/BC): Since each operator needs 0.5 minute to perform the assigned duties, the line is in perfect balance, and 960 parts per day can be produced.
27. Assembly-Line Balancing Cycle timeis the interval between successive outputs coming off the assembly line. In the previous example, with one workstation, the cycle time is 1 minute; that is, one completed assembly is produced every minute. If two workstations are used, the cycle time is 0.5 minute/unit. If three workstations are used, the cycle time is still 0.5 minute/unit, because task A is the bottleneck, or slowest operation. The line can produce only one assembly every 0.5 minute.
28. Assembly-Line Balancing Cycle time (CT) is related to the output (R) by the following equation: CT = A/R [8.2] A = available time to produce the output. The output (R) is normally the demand forecast in units, adjusted for on-hand inventory if appropriate, or orders released to the factory. Both A and R must have the same time units of measure (hour, day, week, month, and so on).
29. Assembly-Line Balancing Minimum number of workstations required = Sum of task times/Cycle time = t/CT [8.3] Total Time Available = (Number of work stations)×(Cycle Time) = (N )(CT ) [8.4] Total Idle Time = (N )(CT ) − t [8.5] Assembly-line Efficiency = t/(N ×CT ) [8.6] Balance Delay = 1 − Assembly-line Efficiency [8.7]
30. Assembly-Line Balancing Line balancing approaches use decision rules, or heuristics, to assign tasks to workstations to attempt to minimize the amount of idle time at workstations, but do not guarantee optimal solutions. Examples: Assign the task with the longest task time first to a workstation if the cycle time would not be exceeded. Assign the shortest task first.
31. Assembly-Line Balancing Solved Problem
32. Exhibit 8.8 A Typical In-Line Skate
33. Exhibit 8.9 Precedence Network and Workstation Assignment
34. Assembly Line Balance for In-Line Skate WorkstationTasks Total TimeIdle Time A 1, 2, 5 5.7 0.3 B 3, 4, 6, 7, 8 3.7 2.3 Total 9.4 2.6 Using equations [8.4] to [8.6] we may compute the following: Total Time Available = (Number workstations)(Cycle Time) = (N )(CT ) = (2)(6) = 12 minutes Total Idle Time = (N )(CT ) − t = (2)(6) - 9.4 = 2.6 minutes Assembly-line Efficiency =  t/(N ×CT ) = 9.4/(2 × 6) = 78.3%
35. Designing Process Layouts Arrangement of departments or work centers to minimize costs associated with material movement or maximizing “closeness ratings” between departments. Software packages: CRAFT ALDEP CORELAP
36. Workplace Design Key Questions: Who will use the workplace? Will the workstation be shared? How much space is required? How will the work be performed? What tasks are required? How much time does each task take? How much time is required to set up for the workday or for a particular job? How might the tasks be grouped into work activities most effectively?
37. Workplace Design Key Questions: What technology is needed? Employees may need a computer or access to customer records and files, special equipment, intercoms, and other forms of technology. What must the employee be able to see? What must the employee be able to hear? What environmental and safety issues need to be addressed?
38. Exhibit 8.10 Pizza Preparation Workplace Design
39. Workplace Design Safety and the work environment: The job should be designed so that it will be highly unlikely that a worker can injure himself or herself. The worker must be educated in the proper use of equipment and the methods designed for performing the job. The surrounding environment must be conducive to safety. Ergonomicsis concerned with improving productivity and safety by designing workplaces, equipment, instruments, computers, workstations, and so on that take into account the physical capabilities of people.
40. The Human Side of Work A job is the set of tasks an individual performs. Job design involves determining the specific job tasks and responsibilities, the work environment, and the methods by which the tasks will be carried out to meet the goals of operations. Job enlargementis the horizontal expansion of the job to give the worker more variety—although not necessarily more responsibility. Job enrichmentis vertical expansion of job duties to give the worker more responsibility.
41. Teams Natural work teams, which perform entire jobs, rather than specialized, assembly-line work Virtual teams, in which members communicate by computer, take turns as leaders, and join and leave the team as necessary Self-managed teams (SMTs), which are empowered work teams that also assume many traditional management responsibilities
42. BankUSA: Cash Movement Case Study What is the best way to group the work represented by the 16 work groups for an average demand of 306 outgoing wires per day? What is your line balance if peak demand is 450 wires per day? What is assembly-line efficiency for each line balance solution? How many people are needed for outgoing wires using assembly line balancing methods versus the current staffing level of 11 full-time equivalent employees? How many staff members do you need for the outgoing wire process if you eliminate all rework? What are your final recommendations?
43. Assembly Line Homework Problems
44. Assembly Line Homework Problems
45. Assembly Line Homework Problems
46. Extra Slide