capacity

Chapter 5: 

Chapter 5 Capacity Planning

Capacity Planning: 

Capacity Planning Capacity is the upper limit or ceiling on the load that an operating unit can handle. The basic questions in capacity handling are: What kind of capacity is needed? How much is needed? When is it needed?

Importance of Capacity Decisions: 

Impacts ability to meet future demands Affects operating costs Major determinant of initial costs Involves long-term commitment Affects competitiveness Affects ease of management Importance of Capacity Decisions

Various Capacities: 

Various Capacities Design capacity Maximum obtainable output Effective capacity, expected variations Maximum capacity subject to planned and expected variations such as maintenance, coffee breaks, scheduling conflicts. Actual output, unexpected variations and demand Rate of output actually achieved--cannot exceed effective capacity. It is subject to random disruptions: machine break down, absenteeism, material shortages and most importantly the demand.

Efficiency and Utilization: 

Efficiency and Utilization This definition of efficiency is not used very much. Utilization is more important.

Efficiency/Utilization Examplefor a Trucking Company: 

Design capacity = 50 trucks/day available Effective capacity = 40 trucks/day, because 20% of truck capacity goes through planned maintenance Actual output = 36 trucks/day, 3 trucks delayed at maintenance, 1 had a flat tire Efficiency/Utilization Example for a Trucking Company

Determinants of Effective Capacity/Output: 

Determinants of Effective Capacity/Output Facilities, layout Products or services, product mixes/setups Processes, quality Human considerations, motivation Operations, scheduling and synchronization problems Supply Chain factors, material shortages External forces, regulations Caution: While discussing these the book considers effective capacity almost synonymous to output.

Some Possible Growth/Decline Patterns: 

Some Possible Growth/Decline Patterns Figure 5-1

Developing Capacity Alternatives : 

Developing Capacity Alternatives Design flexibility into systems, modular expansion Take a “big picture” approach to capacity changes, hotel rooms, car parks, restaurant seats Differentiate new and mature products, pay attention to the life cycle, demand variability vs. discontinuation Prepare to deal with capacity “chunks”, no machine comes in continuous capacities Attempt to smooth out capacity requirements, complementary products, subcontracting Identify the optimal operating level, facility size

Outsourcing: Make or Buy: 

Outsourcing: Make or Buy Outsourcing: Obtaining a good or service from an external provider Decide on outsourcing by considering Available capacity Expertise Quality considerations The nature of demand: Stability Cost Risk: Loss of control over operations with outsourcing; loss of know-how. Loss of revenue.

Evaluating Alternatives: Facility Size: 

Evaluating Alternatives: Facility Size Production units have an optimal rate of output for minimal cost.

Evaluating Alternatives: Facility Size: 

Evaluating Alternatives: Facility Size Minimum cost & optimal operating rate are functions of size of production unit.

Planning Service Capacity: 

Need to be near customers Capacity and location are closely tied Inability to store services Capacity must me matched with timing of demand Degree of volatility of demand Peak demand periods Planning Service Capacity

Example: Calculating Processing Requirements: 

Example: Calculating Processing Requirements

Cost-Volume Relationships : 

Cost-Volume Relationships

Cost-Volume Relationships: 

Cost-Volume Relationships

Cost-Volume Relationships: Break-even analysis: 

Cost-Volume Relationships: Break-even analysis

Break-Even Problem with Multiple Fixed Costs: 

Break-Even Problem with Multiple Fixed Costs Quantity FC + VC = TC FC + VC = TC FC + VC = TC Fixed costs and variable costs. Thick lines are fixed costs. 1 machine 2 machines 3 machines

Break-Even Problem with Step Fixed Costs: 

Break-Even Problem with Step Fixed Costs Break even points. TR No break even points in this range

Cost-Volume(Break-even) Analysis: 

Break-even quantity: Level of production that equates total costs to total revenues Assumptions: One product is involved Everything produced can be sold Variable cost per unit is the same with volume Fixed costs do not change with volume Revenue per unit constant with volume Revenue per unit exceeds variable cost per unit Cost-Volume(Break-even) Analysis

Summary: 

Summary Capacity types Efficiency, utilization Break-even analysis

Decision Theory: 

Decision Theory Decision Theory represents a general approach to decision making which is suitable for a wide range of operations management decisions, including:

Decision Theory Elements: 

Decision Theory Elements A set of possible future conditions (call them scenarios) exists that will have a bearing on the results of the decision Uncertain scenarios A list of alternatives for the manager to choose from A known payoff for each alternative under each possible future condition

Payoff TableInput or implied by the problem set up: 

Payoff Table Input or implied by the problem set up Alternatives Low Moderate High Small facility $10 $10 $10 Medium facility $7 $12 $12 Large facility $-4 $2 $16 Possible future demand Present value in $ millions. This payoff table is given as an input.

Decision Making under Uncertainty: 

Decision Making under Uncertainty When maximizing an objective: MaxiMin - Choose the alternative which has the maximum of minimum possible payoffs for each alternative. Conservative strategy because tries to make the best of the worst possible outcome (for each decision). Which facility? MaxiMax - Choose the alternative with the largest possible payoff. Radical strategy. Which facility? Average(Laplace) - Choose the alternative with the best average payoff of any of the alternatives. Which facility?

Decision Making under Uncertainty: 

Decision Making under Uncertainty When minimizing an objective: Say cost. MiniMax - Choose the alternative which has the minimum of the maximum possible costs for each alternative. Conservative strategy. MiniMin - Choose the alternative with the least possible cost. Radical strategy. Average(Laplace) - Choose the alternative with the minimum average cost of any of the alternatives. Average cost may not be a good indicator. Some alternatives may have more risk than others. In that case, it is ok to choose a slightly costly alternative with low risk.

Example: Hyatt at the Airport “some time ago”Construct the payoff matrix: 

Example: Hyatt at the Airport “some time ago” Construct the payoff matrix

Payoff Matrix for MaxiMax, MaxiMin: 

Payoff Matrix for MaxiMax, MaxiMin

Regret: What I have done against what I could have done. MiniMax Regret. : 

Regret: What I have done against what I could have done. MiniMax Regret.

Summary: 

Summary Capacity types Efficiency, utilization Break-even analysis Decision Theory (decision making under uncertainty)