Capacity Planning For Products and Services Learning Objectives
Capacity Planning For Products and Services
Learning Objectives § § § Explain the importance of capacity planning. Discuss ways of defining and measuring capacity. Describe the determinants of effective capacity. Discuss the major considerations related to developing capacity alternatives. Briefly describe approaches that are useful for evaluating capacity alternatives 2
Capacity Planning § Capacity is the upper limit or ceiling on the load that an operating unit can handle. § Capacity also includes § § § Equipment Space Employee skills § The basic questions in capacity handling are: § § § What kind of capacity is needed? How much is needed? When is it needed? 3
Importance of Capacity Decisions 1. Impacts ability to meet future demands 2. Affects operating costs 3. Major determinant of initial costs 4. Involves long-term commitment 5. Affects competitiveness 6. Affects ease of management 7. Globalization adds complexity 8. Impacts long range planning 4
Capacity § Design capacity § maximum output rate or service capacity an operation, process, or facility is designed for § Effective capacity § Design capacity minus allowances such as personal time, maintenance, and scrap § Actual output § Rate of output actually achieved--cannot exceed effective capacity. 5
Efficiency and Utilization Efficiency = Utilization = Actual output Effective capacity Actual output Design capacity Both measures expressed as percentages (%) 6
Efficiency/Utilization Example Design capacity = 50 trucks/day Effective capacity = 40 trucks/day Actual output = 36 units/day Efficiency = Utilization = Actual output = Effective capacity Actual output Design capacity 36 units/day 40 units/ day = 36 units/day 50 units/day = 90% = 72% 7
Determinants of Effective Capacity § § Facilities (design, location, layout, environment) Product and service factors (design, product mix) Process factors (quantity capacity, quality capacity) Human factors (job content, job design, training & experience, motivation, compensation, learning rate, absenteeism and turnover) § Policy factors § Operational factors (scheduling, materials management, QA, maintenance, breakdown) § Supply chain factors § External factors (standard, safety regulation, unions, pollution control standard) 8
Strategy Formulation Capacity strategy for long-term demand patterns involve; § Growth rate and variability of demand § Cost of building and operating facilities of various size § Rate and direction of technology changes § Behavior of competitors § Availability of capital and other inputs 9
Key Decisions of Capacity Planning 1. Amount of capacity needed • Capacity cushion (100% - Utilization) 2. Timing of changes 3. Need to maintain balance of the system 4. Extent of flexibility of facilities and workforce Capacity cushion – extra demand intended to offset uncertainty 10
Steps for Capacity Planning 1. Forecast future capacity requirements 2. Evaluate existing capacity 3. Identify alternatives 4. Conduct financial analysis 5. Assess key qualitative issues 6. Select one alternative 7. Implement alternative chosen 8. Monitor results 11
Forecasting Capacity Requirements § Long-term vs. short-term capacity needs § Long-term relates to overall level of capacity such as facility size, trends, and cycles § Short-term relates to variations from seasonal, random, and irregular fluctuations in demand 12
Calculating Processing Requirements Working 8 -hour shift, 250 day/year Annual capacity = 2000 hours Machine required to handle these job = 5, 800 /2, 000 = 2. 90 Machine required to handle these job = 3 machines 13
Planning Service Capacity § Need to be near customers § Capacity and location are closely tied § Inability to store services § Capacity must be matched with timing of demand § Degree of volatility of demand § Peak demand periods 14
In-House or Outsourcing (Make or Buy) 1. 2. 3. 4. 5. 6. Available capacity Expertise Quality considerations Nature of demand Cost Risk 15
Developing Capacity Alternatives 1. Design flexibility into systems 2. Take stage of life cycle into account 3. Take a “big picture” approach to capacity changes (to focus bottleneck) 4. Prepare to deal with capacity “chunks” 5. Attempt to smooth out capacity requirements 6. Identify the optimal operating level (economy of scale) 16
Product Life Cycle Company Strategy/Issues Introduction Growth Maturity Best period to increase market share Practical to change price or quality image Poor time to change image, price, or quality R&D engineering is critical Strengthen niche Competitive costs become critical Defend market position CD-ROM Internet Sales Decline Cost control critical Fax machines Drive-through restaurants Color printers Flat-screen monitors DVD 3 1/2” Floppy disks 17
OM Strategy/Issues Product Life Cycle Introduction Growth Maturity Decline Product design and development critical Frequent product and process design changes Short production runs High production costs Limited models Attention to quality Forecasting critical Product and process reliability Competitive product improvements and options Increase capacity Shift toward product focus Enhance distribution Standardization Less rapid product changes – more minor changes Optimum capacity Increasing stability of process Long production runs Product improvement and cost cutting Little product differentiation Cost minimization Overcapacity in the industry Prune line to eliminate items not returning good margin Reduce capacity 18
Bottleneck Operation Machine #1 Machine #2 Bottleneck operation: An operation in a sequence of operations whose capacity is lower than that of the other operations 10/hr 30/hr 10/hr Machine #3 Bottleneck Operation 30/hr 10/hr Machine #4 10/hr 19
Bottleneck Operation 1 20/hr. Operation 2 10/hr. Operation 3 15/hr. 10/hr. Maximum output rate limited by bottleneck 20
Optimal Rate of Output Average cost per unit Production units have an optimal rate of output for minimal cost. Minimum average cost per unit Minimum cost 0 Rate of output 21
Economies of Scale § Economies of scale § If the output rate is less than the optimal level, increasing output rate results in decreasing average unit costs § Diseconomies of scale § If the output rate is more than the optimal level, increasing the output rate results in increasing average unit costs 22
Economies of Scale Average cost per unit Minimum cost & optimal operating rate are functions of size of production unit. 0 Small plant Medium plant Large plant Output rate 23
Evaluating Alternatives § Cost-volume analysis § Break-even point § Financial analysis § Cash flow § Present value § Decision theory § Waiting-line analysis 24
Amount ($) Cost-Volume Relationships c l ta t s o To C V = le b ia s co t ) C (V r a lv ta o T C F + Fixed cost (FC) 0 Q (volume in units) 25
Amount ($) Cost-Volume Relationships 0 e u n e v e r l a t o T Q (volume in units) 26
Cost-Volume Relationships e u n t i f o e Pr r al t t s o c To l a t To Amount ($) ve 0 BEP units Q (volume in units) BEP = Break Even Point 27
Break-Even Problem with Step Fixed Costs C T C= V + FC TC = C F V + C TC = C V 3 machines 2 machines 1 machine Quantity Step fixed costs and variable costs. 28
Break-Even Problem with Step Fixed Costs $ BEP 3 BEP 2 TC TC 3 TC 2 TR 1 Quantity Multiple break-even points 29
Assumptions of Cost-Volume Analysis 1. One product is involved 2. Everything produced can be sold 3. Variable cost per unit is the same regardless of volume 4. Fixed costs do not change with volume 5. Revenue per unit constant with volume 6. Revenue per unit exceeds variable cost per unit 30
Financial Analysis § Cash Flow - the difference between cash received from sales and other sources, and cash outflow for labor, material, overhead, and taxes. § Present Value - the sum, in current value, of all future cash flows of an investment proposal. 31
Decision Theory § Helpful tool for financial comparison of alternatives under conditions of risk or uncertainty § Suited to capacity decisions 32
Waiting-Line Analysis § Useful for designing or modifying service systems § Waiting-lines occur across a wide variety of service systems § Waiting-lines are caused by bottlenecks in the process § Helps managers plan capacity level that will be cost-effective by balancing the cost of having customers wait in line with the cost of additional capacity 33
Decision Theory represents a general approach to decision making which is suitable for a wide range of operations management decisions, including: Capacity planning Product and service design Location planning Equipment selection 34
Decision Theory Elements § A set of possible future conditions exists that will have a bearing on the results of the decision § A list of alternatives for the manager to choose from § A known payoff for each alternative under each possible future condition 35
Decision Theory Process § Identify possible future conditions called states of nature § Develop a list of possible alternatives, one of which may be to do nothing § Determine the payoff associated with each alternative for every future condition § If possible, determine the likelihood of each possible future condition § Evaluate alternatives according to some decision criterion and select the best alternative 36
Causes of Poor Decisions Bounded Rationality The limitations on decision making caused by costs, human abilities, time, technology, and availability of information 37
Causes of Poor Decisions (Cont’d) Suboptimization The result of different departments each attempting to reach a solution that is optimum for that department 38
Decision Process 1. 2. 3. 4. 5. 6. 7. Identify the problem Specify objectives and criteria for a solution Develop suitable alternatives Analyze and compare alternatives Select the best alternative Implement the solution Monitor to see that the desired result is achieved 39
Decision Environments § Certainty - Environment in which relevant parameters have known values § Risk - Environment in which certain future events have probable outcomes § Uncertainty - Environment in which it is impossible to assess the likelihood of various future events 40
Decision Making under Uncertainty Maximin - Choose the alternative with the best of the worst possible payoffs Maximax - Choose the alternative with the best possible payoff Laplace - Choose the alternative with the best average payoff of any of the alternatives Minimax Regret - Choose the alternative that has the least of the worst regrets 41
Decision Making Under Risk § Risk: The probability of occurrence for each state of nature is known § Risk lies between the extremes of uncertainty and certainty § Expected monetary value (EMV) criterion: § The best expected value among alternatives § Determine the expected payoff of each alternative, and choose the alternative with the best expected payoff 42
Decision Trees § Decision tree: a Schematic representation of the available alternatives and their possible consequences. § Useful for analyzing situations that involve sequential decisions 43
Format of a Decision Tree Decision Point Chance Event ’ A e s o o h C State ture a n f o of nat 1 ho C 1 e r u t f na 2 o e t a e os St ’ 2 A State of nat ure 2 A’ 1 e s o o Ch Payoff 2 Choose A’ 2 Payoff 3 e. A s o o h C ’ 3 Payoff 4 Choose A’ 4 Payoff 5 2 ure 2 B 1 Payoff 6 44
Example of a Decision Tree. 4) Decision Point Chance Event l al sm ld i u B (0 d n a em d Low High dema 2 nd (0. 6) B 1 ld ui B 0. 4) ( d n ema 2 d w o L r la ge High dema nd (0. 6) 40 M ing h t o n Do Overtime 50 M Expand 55 M 40 M th Do no ing 10 M Reduce price 50 M 70 M 45
Expected Value of Perfect Information Expected value of perfect information: the difference between the expected payoff under certainty and the expected payoff under risk Expected value of Expected payoff perfect information = under certainty - Expected payoff under risk 46
Sensitivity Analysis § Sensitivity Analysis: Determining the range of probability for which an alternative has the best expected payoff § Useful for decision makers to have some indication of how sensitive the choice of an alternative is to changes in one or more of these values 47
Example ตารางแสดง Payoff ของแตละทางเลอก State of nature #1 #2 Alternative A 4 12 B 16 2 C 12 8 จงเขยนภาพแสดง Sensitivity 48
Sensitivity Analysis #1 Payoff 16 14 12 10 8 6 4 2 0 #2 Payoff B C B best C best A A best Sensitivity analysis: determine the range of probability for which an alternative has the best expected payoff 16 14 12 10 8 6 4 2 0 49
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