Chapter 14 Sales and Capacity Planning Lecture Outline • • • • • • The Sales and Operations Planning Process Strategies for Adjusting Capacity Strategies for Managing Demand Quantitative Techniques for Aggregate Planning Hierarchical Nature of Planning Aggregate Planning for Services Copyright 2011 John Wiley & Sons, Inc. 14-2 Sales and Operations Planning • Determines resource capacity to meet demand over an intermediate time horizon • Aggregate refers to sales and operations planning for product lines or families • Sales and Operations planning (S&OP) matches supply and demand • Objectives • Establish a company wide plan for allocating resources • Develop an economic strategy for meeting demand Copyright 2011 John Wiley & Sons, Inc. 14-3 Sales and Operations Planning Process Copyright 2011 John Wiley & Sons, Inc. 14-4 Monthly S&OP Planning Process Copyright 2011 John Wiley & Sons, Inc. 14-5 Meeting Demand Strategies • Adjusting capacity • Resources to meet demand are acquired and maintained over the time horizon of the plan • Minor variations in demand are handled with overtime or under-time • Managing demand • Proactive demand management Copyright 2011 John Wiley & Sons, Inc. 14-6 Strategies for Adjusting Capacity • Level production • Producing at a constant rate and using inventory to absorb fluctuations in demand • Chase demand • Hiring and firing workers to match demand • Peak demand • Maintaining resources for high-demand levels Copyright 2011 John Wiley & Sons, Inc. 14-7 Strategies for Adjusting Capacity • Overtime and under-time • Increase or decrease working hours • Subcontracting • Let outside companies complete the work • Part-time workers • Hire part-time workers to complete the work • Backordering • Provide the service or product at a later time period Copyright 2011 John Wiley & Sons, Inc. 14-8 Level Production Units Demand Production Time Copyright 2011 John Wiley & Sons, Inc. 14-9 Chase Demand Demand Units Production Time Copyright 2011 John Wiley & Sons, Inc. 14-10 Strategies for Managing Demand • Shifting demand into other time periods – Incentives – Sales promotions – Advertising campaigns • Offering products or services with counter-cyclical demand patterns • Partnering with suppliers to reduce information distortion along the supply chain Copyright 2011 John Wiley & Sons, Inc. 14-11 Quantitative Techniques For AP • • • • • Pure Strategies Mixed Strategies Linear Programming Transportation Method Other Quantitative Techniques Copyright 2011 John Wiley & Sons, Inc. 14-12 Pure Strategies QUARTER SALES FORECAST (LB) Spring Summer Fall Winter Hiring cost Firing cost Inventory carrying cost Regular production cost per pound Production per employee Beginning work force Copyright 2011 John Wiley & Sons, Inc. 80,000 50,000 120,000 150,000 = $100 per worker = $500 per worker = $0.50 pound per quarter = $2.00 = 1,000 pounds per quarter = 100 workers 14-13 Level Production Strategy Level production (50,000 + 120,000 + 150,000 + 80,000) = 100,000 pounds 4 QUARTER Spring Summer Fall Winter SALES FORECAST 80,000 50,000 120,000 150,000 PRODUCTION PLAN INVENTORY 100,000 100,000 100,000 100,000 400,000 20,000 70,000 50,000 0 140,000 Cost of Level Production Strategy (400,000 X $2.00) + (140,00 X $.50) = $870,000 Copyright 2011 John Wiley & Sons, Inc. 14-14 Chase Demand Strategy QUARTER SALES PRODUCTION FORECAST PLAN Spring Summer Fall Winter 80,000 50,000 120,000 150,000 80,000 50,000 120,000 150,000 WORKERS NEEDED 80 50 120 150 WORKERS WORKERS HIRED FIRED 0 0 70 30 20 30 0 0 100 50 Cost of Chase Demand Strategy (400,000 X $2.00) + (100 x $100) + (50 x $500) = $835,000 Copyright 2011 John Wiley & Sons, Inc. 14-15 Level Production with Excel Cost of level production = inventory costs + production costs Input by user =400,000/4 Copyright 2011 John Wiley & Sons, Inc. Inventory at end of summer 14-16 Chase Demand with Excel No. of workers hired in fall Workforce requirements calculated by system Production input by user; production =demand Copyright 2011 John Wiley & Sons, Inc. Cost of chase demand = hiring + firing + production 14-17 Mixed Strategy • Combination of Level Production and Chase Demand strategies • Example policies • no more than x% of workforce can be laid off in one quarter • inventory levels cannot exceed x dollars • Some industries may shut down manufacturing during the low demand season and schedule employee vacations during that time Copyright 2011 John Wiley & Sons, Inc. 14-18 General Linear Programming (LP) Model • LP gives an optimal solution, but demand and costs must be linear • Let • • • • • Wt = workforce size for period t Pt =units produced in period t It =units in inventory at the end of period t Ft =number of workers fired for period t Ht = number of workers hired for period t Copyright 2011 John Wiley & Sons, Inc. 14-19 LP MODEL Minimize Z = $100 (H1 + H2 + H3 + H4) + $500 (F1 + F2 + F3 + F4) + $0.50 (I1 + I2 + I3 + I4) + $2 (P1 + P2 + P3 + P4) Subject to Demand constraints Production constraints Work force constraints Copyright 2011 John Wiley & Sons, Inc. P1 - I1 I1 + P2 - I2 I2 + P3 - I3 I3 + P4 - I4 1000 W1 1000 W2 1000 W3 1000 W4 100 + H1 - F1 W1 + H2 - F2 W2 + H3 - F3 W3 + H4 - F4 = 80,000 = 50,000 = 120,000 = 150,000 = P1 = P2 = P3 = P4 = W1 = W2 = W3 = W4 (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) 14-20 Setting up the Spreadsheet Target cell; cost of solution goes here Solver will put the solution here When model is complete, Solve Cells where solution appears Click here next Demand Constraint Production Constraint Workforce Constraint Copyright 2011 John Wiley & Sons, Inc. 14-21 Setting up the Spreadsheet Click these boxes Copyright 2011 John Wiley & Sons, Inc. 14-22 The LP Solution Cost of optimal solution Solution is a mix of inventory, hiring and firing Optimal production plan Extra report options Copyright 2011 John Wiley & Sons, Inc. 14-23 Level Production for Quantum Cost of level production Excel calculates these Input by user Level = 12,000/12 = 1,000 Copyright 2011 John Wiley & Sons, Inc. 14-24 Chase Demand for Quantum No. workers hired in Feb. Cost of chase demand Excel calculates these Input by user Copyright 2011 John Wiley & Sons, Inc. 14-25 LP Solution for Quantum Optimal solution Constraint equations in these cells Solver found this solution Copyright 2011 John Wiley & Sons, Inc. 14-26 Transportation Method QUARTER EXPECTED DEMAND REGULAR CAPACITY OVERTIME CAPACITY SUBCONTRACT CAPACITY 1 2 3 4 900 1500 1600 3000 1000 1200 1300 1300 100 150 200 200 500 500 500 500 Regular production cost Overtime production cost Subcontracting cost Inventory holding cost Beginning inventory Copyright 2011 John Wiley & Sons, Inc. $20/unit $25/unit $28/unit $3/unit-period 300 units 14-27 Transportation Tableau Copyright 2011 John Wiley & Sons, Inc. 14-28 Transportation Tableau Copyright 2011 John Wiley & Sons, Inc. 14-29 Burruss’ Production Plan REGULAR SUBENDING PERIOD DEMAND PRODUCTION OVERTIME CONTRACT INVENTORY 1 2 3 4 Total 900 1500 1600 3000 7000 Copyright 2011 John Wiley & Sons, Inc. 1000 1200 1300 1300 4800 100 150 200 200 650 0 250 500 500 1250 500 600 1000 0 2100 14-30 Excel and Transportation Method Period 2’s ending inventory Regular production for period 1 Cost of solution Copyright 2011 John Wiley & Sons, Inc. 14-31 Other Quantitative Techniques • Linear decision rule (LDR) • Search decision rule (SDR) • Management coefficients model Copyright 2011 John Wiley & Sons, Inc. 14-32 Hierarchical Nature of Planning Production Planning Capacity Planning Resource Level Product lines or families Sales and Operations Plan Resource requirements plan Plants Individual products Master production schedule Rough-cut capacity plan Critical work centers Components Material requirements plan Capacity requirements plan All work centers Manufacturing operations Shop floor schedule Input/ output control Items Copyright 2011 John Wiley & Sons, Inc. Individual machines 14-33 Disaggregation • Breaking an aggregate plan into more detailed plans • Create Master Production Schedule for Material Requirements Planning Copyright 2011 John Wiley & Sons, Inc. 14-34 Collaborative Planning • Sharing information and synchronizing production across supply chain • Part of CPFR (collaborative planning, forecasting, and replenishment) • involves selecting products to be jointly managed, creating a single forecast of customer demand, and synchronizing production across supply chain Copyright 2011 John Wiley & Sons, Inc. 14-35 Available-to-Promise (ATP) • Quantity of items that can be promised to customer • Difference between planned production and customer orders already received AT in period 1 = (On-hand quantity + MPS in period 1) – (CO until the next period of planned production) ATP in period n = (MPS in period n) – (CO until the next period of planned production) • Capable-to-promise • quantity of items that can be produced and mad available at a later date Copyright 2011 John Wiley & Sons, Inc. 14-36 ATP Copyright 2011 John Wiley & Sons, Inc. 14-37 ATP Copyright 2011 John Wiley & Sons, Inc. 14-38 ATP Take excess units from April ATP in April = (10+100) – 70 = 40 ATP in May = 100 – 110 = -10 ATP in June = 100 – 50 = 50 Copyright 2011 John Wiley & Sons, Inc. = 30 =0 14-39 Rule Based ATP Product Request Yes Is the product available at this location? No Available-topromise Yes Is an alternative product available at this location? No Allocate inventory Yes Is this product available at a different location? No Copyright 2011 John Wiley & Sons, Inc. Is an alternative product available at an alternate location? Yes No Allocate inventory Capable-topromise date Is the customer willing to wait for the product? No Available-topromise Yes Revise master schedule Trigger production Lose sale 14-40 Aggregate Planning for Services • • • • Most services cannot be inventoried Demand for services is difficult to predict Capacity is also difficult to predict Service capacity must be provided at the appropriate place and time • Labor is usually the most constraining resource for services Copyright 2011 John Wiley & Sons, Inc. 14-41 Yield Management Copyright 2011 John Wiley & Sons, Inc. 14-42 Yield Management Copyright 2011 John Wiley & Sons, Inc. 14-43 Yield Management NO-SHOWS PROBABILITY P(N < X) 0 1 2 3 .15 .25 .30 .30 .00 .15 .40 .70 .517 Optimal probability of no-shows Cu 75 P(n < x)  = = .517 Cu + C o 75 + 70 Hotel should be overbooked by two rooms Copyright 2011 John Wiley & Sons, Inc. 14-44 Copyright 2011 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permission Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages caused by the use of these programs or from the use of the information herein. Copyright 2011 John Wiley & Sons, Inc. 14-45