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Chapter 6 Process Selection and Facility Layout. Facilities and Equipment. Capacity Planning. Forecasting. Facility Layout. Product and Service Design. Process Selection. Work Design. Technological Change. Process Selection as Part of System Design.
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Chapter 6Process SelectionandFacility Layout Saba Bahouth – UCO
Facilities andEquipment CapacityPlanning Forecasting Facility Layout Product andService Design ProcessSelection WorkDesign TechnologicalChange Process Selection as Part of System Design • Deciding on the waythe production of goods or services will be organized Saba Bahouth – UCO
Process Choice Decisions Three Types of Goods and Services Custom, or make-to-order, goods and services are generally produced and delivered as one-of-a-kind or in small quantities, and are designed to meet specific customers’ specifications. Examples: ships, weddings, certain jewelry, estate plans, buildings, and surgery. Option, or assemble-to-order, goods and services are configurations of standard parts, subassemblies, or services that can be selected by customers from a limited set. Examples:desktop computers, Subway sandwiches, vacation in tour, BBA Standard, or make-to-stock, goods and services are made according to a fixed design, and the customer has no options from which to choose. Examples: appliances, shoes, sporting goods, credit cards, on-line Web-based courses, and bus service. Saba Bahouth – UCO
The Big Picture Types of Goods and Services Custom make-to-order Option assemble-to-order Standard make-to-stock Types of Processes 1. Projects 2. Job-Shop 3. Batch 4. Repetitive/ (Assembly Lines) 5. Continuous Types of Layout 1. Fixed Position Layout 2. Process/Functional Layout 3. Product Layout 4. Combination Layout Saba Bahouth – UCO
Job-Shop (intermittent process) Process/Functional Layout Repetitive (assembly line) Product Layout Continuum Make to Stock Low variety, high volume High utilization (70% - 95%) Specialized equipment Make to Order High variety, low volume Low utilization (5% - 25%) General-purpose equipment Types of Processes Projects Job shop:Small scale production Batch:Moderate volume production Repetitive/assembly line:High volumes of standardized goods or services Continuous:Very high volumes of non-discrete goods Batch Continuous Product Layout Flexible equipment Saba Bahouth – UCO
Batch Repetitive Saba Bahouth – UCO
Volume, Variety and Process Matrix Low-Volume Repetitive Process High-Volume Process/Functional focus (Intermittent) projects, job shop (machine, print, carpentry) Kinko’s Different Products: (High Variety) One or few units per run, high variety (allows customization) Mass Customization (difficult to achieve, but huge rewards) Dell Computer Co. (Batch) Different Modules Modest runs, standardized modules Repetitive (autos, motorcycles) Honda Poor strategy Product focus (steel, glass) Nucor Steel Different Attributes only (Low Variety) (such as grade, quality, size, thickness, etc.) Long runs only Saba Bahouth – UCO
0.1 min 0.7 min 1.0 min 0.5 min 0.2 min Assembly-Line Balancing Saba Bahouth – UCO
0.1 min 0.7 min 1.0 min 0.5 min 0.2 min Assembly-Line Balancing • Assembly-Line Balancing • An assembly line isa product layout dedicated to combining the components of a good or service that has been created previously. • Assembly line balancing is a technique for grouping tasks to balance the workload on workstations. • Cycle time (CT) is the interval between successive outputs. • Min. number of WS needed = Sum of task times/Cycle time = t / CT • Individual WS efficiency = t / CT • Assembly Line Efficiency = t / (N*CT) Saba Bahouth – UCO
0.1 min 0.7 min 1.0 min 0.5 min 0.2 min Assembly-Line Balancing • 5 workstations: CT = 1 minute; 1 assembly every 1 minute. • 3 workstations: CT = 1 minute; 1 assembly every 1 minute. • 1 workstation: CT = 2.5 minutes; 1 assembly every 2.5 minutes. • Maximum Allowed Cycle Time: • MACT = A / R • where A = Available time to produce the output (Hrs/day or Min/day) • R = Required output Rate (units/day) • (be careful with time units) • Example: [8hrs/day] / [160units/day] = 0.05 hrs/unit or 3 minutes Saba Bahouth – UCO
Funnel Analogy of Bottlenecks Saba Bahouth – UCO
Little’s Law J.D. Little (1961) developed a simple formula that explains the relationship between flow time (T), throughput (R) and work-in-process (WIP), which is known as Little’s Law. WORK-IN-PROCESS (WIP) = THROUGHPUT (R) * FLOW TIME (T) Assume: Throughput = 30 units/hr Flow time = 20 minutes or 1/3 hr Therefore WIP= 30 units/hr x 1/3 hr = 10 units Consider a voting facility that processes an average of 50 people per hour and that on average, it takes 10 minutes for each person to complete the voting process. WIP = R*T WIP = 50 voters/hr*(10 minutes/60 minutes per hour) WIP = 8.33 voters Saba Bahouth – UCO
Solved Problem An accounts receivable manager processes 200 bills per day with an average processing time of 5 working days. What is the average number of bills in her office? What if she reduces the time from 5 to 1 day using better technology? Solution: Saba Bahouth – UCO
Automation Automation: Machinery that has sensing and control devices that enables it to operate with minimal input from an operator. • Fixed automation • Programmable automation • Machine technology – NCM for drilling, cutting, etc • Automatic identification systems (AIS) – Bar codes, toll pass • Process control – Glass temperature – QA charts • Vision system - Replacing human inspection: level in medicine bottles • Robot – Imitation of human arm for boring and dangerous jobs • Automated storage and retrieval systems (ASRS) • Automated Guided Vehicles (AGV) • Flexible manufacturing systems (FMS) – One computer system controlling several machines and material handling • Computer-integrated manufacturing (CIM) – One computer system spanning over engineering, inventory, manufacturing, warehousing and shipping Saba Bahouth – UCO
Facilities Layout Layout: the configuration of departments, work centers, and equipment, with particular emphasis on movement of work (customers or materials) through the system • Process/Functional layout • Product layout • Combination layout • Fixed-Position layout (Projects) Saba Bahouth – UCO
222 222 222 111 444 Mill 3333 22222 444 Grind 1111 2222 Assembly 333333333 44444 111 333 333333 Drill 111 111 Gear cutting 111 333 444 Lathes Heat treat Process/Functional Layout Saba Bahouth – UCO
Process/Functional Layout A process/functional layout consists of a functional grouping of equipment or activities that do similar work. Examples: offices, hospitals. Advantages of product layouts include a lower investment in general purpose equipment, flexibility, and the diversity of jobs inherent in a process layout can lead to increased worker satisfaction. Saba Bahouth – UCO
Product Layout A product layout is an arrangement based on the sequence of operations that are performed during the manufacturing or service. Examples: Subway sandwich shops, automobile assembly lines. Advantages of product layouts include lower work-in-process inventories, shorter processing times, less material handling, requires lower labor skills, and simple planning and control systems. Saba Bahouth – UCO
222 222 222 111 444 Mill 3333 22222 444 Grind 1111 2222 Assembly 333333333 44444 111 333 333333 Drill 111 111 Gear cutting 111 333 444 Lathes Heat treat Process/Functional Layout • Cellular Production • Group Technology Saba Bahouth – UCO
Gear cut Heat treat Lathe Mill Drill -1111 -1111 Heat treat Mill Drill Grind 222222222 - 2222 Assembly Heat treat - 3333 3333333333 Lathe Mill Grind Gear cut - 4444 44444444444444 Mill Drill Cellular Manufacturing Layout Saba Bahouth – UCO
Group Technology / Cellular Layout Saba Bahouth – UCO
Forming a Cell Drill Polish Work Cell Saba Bahouth – UCO
1 2 3 4 In 5 Workers 6 10 Out 9 8 7 A U-Shaped Production Line Saba Bahouth – UCO
Process/Functional Layouts Disadvantages • 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 Advantages • Can handle a variety of processing requirements • Not particularly vulnerable to equipment failures • Equipment used is less costly • Possible to use individual incentive plans Saba Bahouth – UCO
Product Layout • Disadvantages • Creates dull, repetitive jobs • Poorly skilled workers may neglect maintenance and quality • Fairly inflexible to changes in volume • Highly susceptible to shutdowns • Needs preventive maintenance • Individual incentive plans are impractical Advantages • High rate of output • Low unit cost • Labor specialization • Low material handling cost • High utilization of labor/equipment • Established routing and scheduling • Easy accounting and purchasing Saba Bahouth – UCO
Service Layouts • Warehouse and storage layouts • Retail layouts • Office layouts • Service layouts must be functional and aesthetically pleasing Saba Bahouth – UCO