Presentation on theme: "Chapter 6 Process Selection and Facility Layout 1Saba Bahouth – UCO."— Presentation transcript:
Chapter 6 Process Selection and Facility Layout 1Saba Bahouth – UCO
Forecasting Product and Service Design Technological Change Capacity Planning Process Selection Facilities and Equipment Facility Layout Work Design Process Selection as Part of System Design Deciding on the way the production of goods or services will be organized 2Saba Bahouth – UCO
Process Choice Decisions Saba Bahouth – UCO3 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.
The Big Picture Saba Bahouth – UCO4 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
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 Types of Processes Job-Shop (intermittent process) Process/Functional Layout Repetitive (assembly line) Product Layout Continuum Make to Order High variety, low volume Low utilization (5% - 25%) General-purpose equipment Make to Stock Low variety, high volume High utilization (70% - 95%) Specialized equipment BatchContinuous Product Layout Flexible equipment Projects 5Saba Bahouth – UCO
Volume, Variety and Process Matrix Different Attributes only (Low Variety) (such as grade, quality, size, thickness, etc.) Long runs only Process/Functional focus (Intermittent) projects, job shop (machine, print, carpentry) Kinkos Repetitive (autos, motorcycles) Honda Product focus (steel, glass) Nucor Steel Different Products: (High Variety) One or few units per run, high variety (allows customization) Different Modules Modest runs, standardized modules Mass Customization (difficult to achieve, but huge rewards) Dell Computer Co. Poor strategy Low-Volume Repetitive ProcessHigh-Volume 8Saba Bahouth – UCO (Batch)
Assembly-Line Balancing Saba Bahouth – UCO10 Assembly-Line Balancing An assembly line is a 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) 0.1 min0.7 min1.0 min0.5 min0.2 min
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 Assembly-Line Balancing Saba Bahouth – UCO11 0.1 min0.7 min1.0 min0.5 min0.2 min
Funnel Analogy of Bottlenecks 12Saba Bahouth – UCO
Littles 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 Littles 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 13Saba 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: 14Saba Bahouth – UCO
Automation: Machinery that has sensing and control devices that enables it to operate with minimal input from an operator. – Fixed automation – Programmable automation 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 15Saba Bahouth – UCO
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) Facilities Layout 16Saba Bahouth – UCO
18 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 – UCO19 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.
A U-Shaped Production Line 1 234 5 6 7 89 10 In Out Workers 24Saba Bahouth – UCO
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 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 25Saba Bahouth – UCO
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 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 26Saba Bahouth – UCO
Warehouse and storage layouts Retail layouts Office layouts Service layouts must be functional and aesthetically pleasing Service Layouts 27Saba Bahouth – UCO