1. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling Engineering Economy Chapter 2: Cost Concepts and Design Economics

2. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling The objective of Chapter 2 is to analyze short-term alternatives when the time value of money is not a factor.

3. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling COST ESTIMATING USED TO Provide information used in setting a selling price for quoting, bidding, or evaluating contracts Determine whether a proposed product can be made and distributed at a profit (eg: price = cost + profit) Evaluate how much capital can be justified for process changes or other improvements Establish benchmarks for productivity improvement programs

4. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling COST ESTIMATING APPROACHES Top-down Approach Bottom-up Approach

5. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling TOP-DOWN APPROACH Uses historical data from similar engineering projects Used to estimate costs, revenues, and other parameters for current project Modifies original data for changes in inflation / deflation, activity level, weight, energy consumption, size, etc … Best use is early in estimating process

6. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling BOTTOM-UP APPROACH More detailed cost-estimating method Attempts to break down project into small, manageable units and estimate costs, etc …. Smaller unit costs added together with other types of costs to obtain overall cost estimate Works best when detail concerning desired output defined and clarified

7. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling COST-DRIVEN DESIGN OPTIMIZATION Must maintain a life-cycle design perspective Ensures engineers consider: Initial investment costs Operation and maintenance expenses Other annual expenses in later years Environmental and social consequences over design life

8. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling DESIGN FOR THE ENVIRONMENT (DFE) This green-engineering approach has the following goals: Prevention of waste Improved materials selection Reuse and recycling of resources

9. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling COST-DRIVEN DESIGN OPTIMIZATION PROBLEM TASKS 1.Determine optimal value for certain alternative ’ s design variable 2.Select the best alternative, each with its own unique value for the design variable

10. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling COST-DRIVEN DESIGN OPTIMIZATION PROBLEM COST TYPES 1.Fixed cost(s) 2.Cost(s) that vary directly with the design variable 3.Cost(s) that vary indirectly with the design variable Simplified Format of Cost Model With One Design Variable Cost = aX + (b / X) + k a is a parameter that represents directly varying cost(s) b is a parameter that represents indirectly varying cost(s) k is a parameter that represents the faced cost(s) X represents the design variable in question (In a particular problem, the parameters a,b and k may actually represent the sum of a group of costs in that category, and the design variable may be raised to some power for either directly or indirectly varying costs.)

11. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling GENERAL APPROACH FOR OPTIMIZING A DESIGN WITH RESPECT TO COST 1.Identify primary cost-driving design variable 2.Write an expression for the cost model in terms of the design variable 3.Set first derivative of cost model with respect to continuous design variable equal to 0. (For discrete design variables, compute cost model for each discrete value over selected range). 4.Solve equation in step 3 for optimum value of continuous design variables 5.For continuous design variables, use the second derivative of the cost model with respect to the design variable to determine whether optimum corresponds to global maximum or minimum.

12. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling Costs can be categorized in several different ways. Fixed cost: unaffected by changes in activity level Variable cost: vary in total with the quantity of output (or similar measure of activity) Incremental cost: additional cost resulting from increasing output of a system by one (or more) units

13. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling More ways to categorize costs Direct: can be measured and allocated to a specific work activity Indirect: difficult to attribute or allocate to a specific output or work activity (also overhead or burden) Standard cost: cost per unit of output, established in advance of production or service delivery

14. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling FIXED, VARIABLE, AND INCREMENTAL COSTS Fixed costs are those unaffected by changes in activity level over a feasible range of operations for the capacity or capability available. Typical fixed costs include insurance and taxes on facilities, general management and administrative salaries, license fees, and interest costs on borrowed capital. When large changes in usage of resources occur, or when plant expansion or shutdown is involved fixed costs will be affected.

15. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling FIXED, VARIABLE, AND INCREMENTAL COSTS Incremental cost is the additional cost that results from increasing the output of a system by one (or more) units. Incremental cost is often associated with “go / no go” decisions that involve a limited change in output or activity level. EXAMPLE the incremental cost of driving an automobile might be $0.27 / mile. This cost depends on: –mileage driven; –mileage expected to drive; –age of car;

16. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling FIXED, VARIABLE, AND INCREMENTAL COSTS Variable costs are those associated with an operation that vary in total with the quantity of output or other measures of activity level. Example of variable costs include: costs of material and labor used in a product or service, because they vary in total with the number of output units -- even though costs per unit remain the same.

17. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling Some useful cost terminology Cash cost: a cost that involves a payment of cash. Book cost: a cost that does not involve a cash transaction but is reflected in the accounting system. Sunk cost: a cost that has occurred in the past and has no relevance to estimates of future costs and revenues related to an alternative course of action.

18. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling More useful cost terminology Opportunity cost: the monetary advantage foregone due to limited resources. The cost of the best rejected opportunity. Life-cycle cost: the summation of all costs related to a product, structure, system, or service during its life span.

19. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling RECURRING AND NONRECURRING COSTS Recurring costs are repetitive and occur when a firm produces similar goods and services on a continuing basis. Variable costs are recurring costs because they repeat with each unit of output. A fixed cost that is paid on a repeatable basis is also a recurring cost: –Office space rental $

20. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling RECURRING AND NONRECURRING COSTS Nonrecurring costs are those that are not repetitive, even though the total expenditure may be cumulative over a relatively short period of time; Typically involve developing or establishing a capability or capacity to operate; Examples are purchase cost for real estate upon which a plant will be built, and the construction costs of the plant itself;

21. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling DIRECT, INDIRECT AND OVERHEAD COSTS Direct costs can be reasonably measured and allocated to a specific output or work activity -- labor and material directly allocated with a product, service or construction activity; Indirect costs are difficult to allocate to a specific output or activity -- costs of common tools, general supplies, and equipment maintenance ;

22. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling Overhead consists of plant operating costs that are not direct labor or material costs – indirect costs, overhead and burden are the same; Prime Cost is a common method of allocating overhead costs among products, services and activities in proportion the sum of direct labor and materials cost ; DIRECT, INDIRECT AND OVERHEAD COSTS

23. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling CASH COST VERSUS BOOK COST Cash cost is a cost that involves payment in cash and results in cash flow; Book cost or noncash cost is a payment that does not involve cash transaction; book costs represent the recovery of past expenditures over a fixed period of time; Depreciation is the most common example of book cost; depreciation is what is charged for the use of assets, such as plant and equipment; depreciation is not a cash flow;

24. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling SUNK COST AND OPPORTUNITY COST A sunk cost is one that has occurred in the past and has no relevance to estimates of future costs and revenues related to an alternative course of action; An opportunity cost is the cost of the best rejected ( i.e., foregone ) opportunity and is hidden or implied;

25. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling LIFE-CYCLE COST Life-cycle cost is the summation of all costs, both recurring and nonrecurring, related to a product, structure, system, or service during its life span. Life cycle begins with the identification of the economic need or want ( the requirement ) and ends with the retirement and disposal activities.

26. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling Figure 2-1

27. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling CAPITAL AND INVESTMENT Investment Cost or capital investment is the capital (money) required for most activities of the acquisition phase; Working Capital refers to the funds required for current assets needed for start-up and subsequent support of operation activities; Operation and Maintenance Cost includes many of the recurring annual expense items associated with the operation phase of the life cycle; Disposal Cost includes non-recurring costs of shutting down the operation;

28. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling STANDARD COSTS Representative costs per unit of output that are established in advance of actual production and service delivery; Standard Cost ElementSources of Data Direct LaborProcess routing sheets, standard times, standard labor rates; Direct MaterialMaterial quantities per unit, standard unit materials cost; Factory Overhead CostsTotal factory overhead costs allocated based on prime costs;

29. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling SOME STANDARD COST USES Estimating future manufacturing or service delivery costs; Measuring operating performance by comparing actual cost per unit with the standard unit cost; Preparing bids on products or services requested by customers; Establishing the value of work-in-process and finished inventories;

30. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling CONSUMER GOODS AND PRODUCER GOODS AND SERVICES Consumer goods and services are those that are directly used by people to satisfy their wants; Producer goods and services are those used in the production of consumer goods and services: machine tools, factory buildings, buses and farm machinery are examples;

31. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling The General Economic Environment Consumer and Producer Foods and Services Measures of Economic Worth Necessities, Luxuries, and Price Demand

32. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling UTILITY AND DEMAND Utility is a measure of the value which consumers of a product or service place on that product or service; Demand is a reflection of this measure of value, and is represented by price per quantity of output;

33. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling PRICE QUANTITY ( OUTPUT )

34. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling The general price-demand relationship The demand for a product or service is directly related to its price according to p=a- bD where p is price, D is demand, and a and b are constants that depend on the particular product or service.

35. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling PRICE QUANTITY ( OUTPUT ) Price equals some constant value minus some multiple of the quantity demanded: p = a - b D a

36. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling PRICE QUANTITY ( OUTPUT ) Price equals some constant value minus some multiple of the quantity demanded: p = a - b D a a = Y-axis (quantity) intercept, (price at 0 amount demanded); b = slope of the demand function;

37. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling Total revenue depends on price and demand. Total revenue is the product of the selling price per unit, p, and the number of units sold, D.

38. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling Calculus can help determine the demand that maximizes revenue. Solving, the optimal demand is

39. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling We can also find maximum profit… Profit is revenue minus cost, so for Differentiating, we can find the value of D that maximizes profit.

40. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling PRICE QUANTITY ( OUTPUT ) Price equals some constant value minus some multiple of the quantity demanded: p = a - b D a a = Y-axis (quantity) intercept, (price at 0 amount demanded); b = slope of the demand function; D = (a – p) / b PRICE Total Revenue = p x D = (a – bD) x D =aD – bD 2 QUANTITY ( OUTPUT ) MR = dTR / dD = a –2bD = 0

41. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling PRICE QUANTITY ( OUTPUT ) Price equals some constant value minus some multiple of the quantity demanded: p = a - b D a a = Y-axis (quantity) intercept, (price at 0 amount demanded); b = slope of the demand function; D = (a – p) / b PRICE Total Revenue = p x D = (a – bD) x D =aD – bD 2 QUANTITY ( OUTPUT ) MR = dTR / dD = a –2bD = 0 MR=0

42. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling PRICE QUANTITY ( OUTPUT ) Price equals some constant value minus some multiple of the quantity demanded: p = a - b D a a = Y-axis (quantity) intercept, (price at 0 amount demanded); b = slope of the demand function; D = (a – p) / b PRICE Total Revenue = p x D = (a – bD) x D =aD – bD 2 QUANTITY ( OUTPUT ) MR = dTR / dD = a –2bD = 0 MR=0 TR = Max

43. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling PRICE QUANTITY ( OUTPUT ) Price equals some constant value minus some multiple of the quantity demanded: p = a - b D a a = Y-axis (quantity) intercept, (price at 0 amount demanded); b = slope of the demand function; D = (a – p) / b PRICE Total Revenue = p x D = (a – bD) x D =aD – bD 2 QUANTITY ( OUTPUT ) MR = dTR / dD = a –2bD = 0 MR=0 TR = Max E > 1 E = 1 E < 1

44. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling Cost / Revenue Quantity ( Output ) Demand Marginal ( Incremental) Cost Cost / Revenue Quantity ( Output ) Demand CfCf CtCt D’ 1 D’ 2 D* ProfitTotal Revenue Maximum Profit Profit is maximum where Total Revenue exceeds Total Cost by greatest amount D’1 and D’2 are breakeven points Marginal Revenue

45. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling Figure 2-4

46. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling And we can find revenue/cost breakeven. Breakeven is found when total revenue = total cost. Solving, we find the demand at which this occurs.

47. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling Figure 2-6

48. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling Engineers must consider cost in the design of products, processes and services. “Cost-driven design optimization” is critical in today’s competitive business environment. In our brief examination we examine discrete and continuous problems that consider a single primary cost driver.

49. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling Two main tasks are involved in cost- driven design optimization. 1.Determine the optimal value for a certain alternative’s design variable. 2.Select the best alternative, each with its own unique value for the design variable. Cost models are developed around the design variable, X.

50. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling Optimizing a design with respect to cost is a four-step process. Identify the design variable that is the primary cost driver. Express the cost model in terms of the design variable. For continuous cost functions, differentiate to find the optimal value. For discrete functions, calculate cost over a range of values of the design variable. Solve the equation in step 3 for a continuous function. For discrete, the optimum value has the minimum cost value found in step 3.

51. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling Here is a simplified cost function. where, a is a parameter that represents the directly varying cost(s), b is a parameter that represents the indirectly varying cost(s), k is a parameter that represents the fixed cost(s), and X represents the design variable in question.

52. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling “Present economy studies” can ignore the time value of money. Alternatives are being compared over one year or less. When revenues and other economic benefits vary among alternatives, choose the alternative that maximizes overall profitability of defect-free output. When revenues and other economic benefits are not present or are constant among alternatives, choose the alternative that minimizes total cost per defect-free unit.

53. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling PRESENT ECONOMY STUDIES When alternatives for accomplishing a task are compared for one year or less (I.e., influence of time on money is irrelevant) Rules for Selecting Preferred Alternative Rule 1 – When revenues and other economic benefits are present and vary among alternatives, choose alternative that maximizes overall profitability based on the number of defect-free units of output Rule 2 – When revenues and economic benefits are not present or are constant among alternatives, consider only costs and select alternative that minimizes total cost per defect-free output

54. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling PRESENT ECONOMY STUDIES Total Cost in Material Selection In many cases, selection of among materials cannot be based solely on costs of materials. Frequently, change in materials affect design, processing, and shipping costs. Alternative Machine Speeds Machines can frequently be operated at different speeds, resulting in different rates of product output. However, this usually results in different frequencies of machine downtime. Such situations lead to present economy studies to determine preferred operating speed.

55. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling PRESENT ECONOMY STUDIES Make Versus Purchase (Outsourcing) Studies A company may choose to produce an item in house, rather than purchase from a supplier at a price lower than production costs if: 1.direct, indirect or overhead costs are incurred regardless of whether the item is purchased from an outside supplier, and 2.The incremental cost of producing the item in the short run is less than the supplier ’ s price The relevant short-run costs of the make versus purchase decisions are the incremental costs incurred and the opportunity costs of resources

56. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling PRESENT ECONOMY STUDIES Make Versus Purchase (Outsourcing) Studies Opportunity costs may become significant when in- house manufacture of an item causes other production opportunities to be foregone (E.G., insufficient capacity) In the long run, capital investments in additional manufacturing plant and capacity are often feasible alternatives to outsourcing.

57. Copyright ©2009 by Pearson Education, Inc. Upper Saddle River, New Jersey 07458 All rights reserved. Engineering Economy, Fourteenth Edition By William G. Sullivan, Elin M. Wicks, and C. Patrick Koelling Home Work (due:Next Class) Read Case Study (2.5, page 71-73) Problem 2-12 (page 75) Problem 2-36 (page 78) Spreadsheet Exercises Problems 2-49(page 80) Identify costs for your study in Tatung University.