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Sales and Operations Planning (Aggregate Planning)
©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Sales and Operations Planning
Strategic and tactical considerations Top-down planning Bottom-up planning Optimization techniques ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Back to Pennington Cabinet
Strategic Capacity Level: Five machines, nine assembly teams Company produces make-to-stock cabinets for sale at Lowe’s, etc. Effective capacity: ,000 jobs per year OR about 420 jobs per month ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Pennington (continued)
Raw Demand for next 6 months: January jobs February March April May June 650 What are our options ? Class discussion before proceeding, what would the students do? ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Pennington (again) . . . Raw Demand Need 450 600
Monthly capacity = 420 300 April ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Sales and Operations Planning (SOP)
Purpose: Select capacity options over the intermediate time horizon Capacity options: Workforces Shifts Overtime Subcontracting Inventories etc. ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Short-Range Plan (days, weeks out) Long-Range Plan (years out)
Time Horizon View . . . Short-Range Plan (days, weeks out) SOP (months out) Long-Range Plan (years out) Capacity levels considered “frozen” in the short-term Changes in adjustable capacity possible fixed ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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SOP continued (2 - 18 months out) “Big Picture” approach to planning
Outside of time frame strategic planning Inside of time frame tactical planning “Big Picture” approach to planning Families or groups (aggregation) of: Products Resources Technologies or skills Provide “rough” estimates ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Position in the Overall Business Planning Cycle
Decisions Time Frame Product and process “Bricks and Mortar” 18+ months Employment and overall inventory levels What demand to meet? 2 to 18 months Specific products and times Scheduling of people and equipment Less than 2 months Long-Range Plans SOP Short-Range ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Inputs to the Process SOPs Demand Management Strategic Capacity Levels
Forecasts of customer demand Need for spares, etc. Pricing Strategic Capacity Levels Existing buildings Processes SOPs External Capacities Suppliers Subcontractors ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Advantages of SOP Negotiated process Functional coordination
“Agreed” demand Functional coordination Budgets and cash flow analyses Reduces operations task to “meeting the plan” ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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SOP Approaches Top-Down Bottom-Up Similar products OR stable mix
Standards available for planning time, cost requirements from history and/or planning documentation Can “Average” product Bottom-Up Different products AND unstable mix Requires forecasts and production data for individual products Can be extremely data- intensive ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Top-Down Planning Develop the aggregate sales forecast and planning values. Translate the sales forecast into resource requirements. Personnel, equipment, materials Generate alternative production plans. Chase, level, mixed Select the best of the plans. Lowest cost, best fit to capability ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Top-Down Example I (Product Data)
% of Total Labor/Unit A100 10% 40 hours B200 50% 20 hours C300 20% 15 hours D400 5% 10 hours E500 F600 ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Top-Down Example II (“Average” Products)
% of Total Labor/Unit A100 10% 40 hours B200 50% 20 hours C300 20% 15 hours D400 5% 10 hours E500 F600 10%(40) + 60%(20) + 20%(15) + 10%(10) = 20 hours ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Top-Down Example III (Conditions or Constraints)
Agreed upon demand to be met for upcoming 12 month period Can vary workforce and inventory levels No backordering “Average” unit requires 20 worker hours Each worker works 160 hours per month Class discussion about where these conditions or constraints can come from: Top management, company culture, general policy, desired service level for customers, etc. ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Top-Down Example IV (Demand Forecast for 12 months)
March 1592 September 2504 April 1400 October May 1200 November 3000 June 1000 December July 1504 January August 1992 February Class discussion about where these conditions or constraints can come from: Top management, company culture, general policy, desired service level for customers, etc. ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Top-Down Example V (Other tidbits of data …)
Hiring cost = $300 Firing cost = $200 Inventory holding cost = $6 / unit / month Start and end with 227 workers (goal) Start and end with about 1000 units in inventory (goal) ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Detail of First Six Months from Level Strategy
Demand Demand in Employee Hours Employees to Meet Production Plan Actual Employees Actual Production Firings Hirings Ending Inventory March 1592 31840 199 252 2016 25 1424 April 1400 28000 175 2040 May 1200 24000 150 2856 June 1000 20000 125 3872 July 1504 30080 188 4384 August 1992 39840 249 4408 Taken in part from Note: We develop a level strategy by setting “Actual Employees” equal to the average required for the 12 month planning period ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Detail of First Six Months from Chase Strategy
Demand Demand in Employee Hours Employees to Meet Production Plan Actual Employees Actual Production Firings Hirings Ending Inventory March 1592 31840 199 28 1000 April 1400 28000 175 24 May 1200 24000 150 25 June 20000 125 July 1504 30080 188 63 August 1992 39840 249 61 Taken in part from the Excel file Ch12-SOP_Chase.xls using Note: We develop a chase strategy by setting “Actual Employees” equal to the number needed in each period ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Another View ... ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Cost Details from the Spreadsheets ...
Level strategy Chase strategy ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Top-Down Example (Other Issues …)
Are complete costs shown? Expand out for budget and cash flow analysis “Input” (suppliers) and “output” (logistics and warehousing) considerations Lead time, materials availability, storage space? Variations in actual production Scrap, rework, equipment breakdowns Input and output considerations such as lead-time, availability, storage space, etc. ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Top-Down Example (Expand the options …)
We can now subcontract production Maximum subcontract of 1400 units per month Cost is $5 more per unit than internal production cost Will this option: 1) increase costs? 2) decrease costs? 3) have no effect on costs? Plan will decrease costs by holding employment steady and using subcontracting last three months (536, 688, and 1176), finishing with 1000 units in inventory – total cost is $136,704. ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Second Approach: “Bottom-Up” SOP
Products with very different requirements Requires forecasts and production data for individual products Can be extremely data-intensive ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Iterative Approach (Similar to Top Down)
©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Detail from Bottom Up Plan
Bill of Labor CSEs Home Gyms Assembly 50 2 Painting 3 Hours of Month Maximum Maximim January 30 200 1900 2200 660 750 February 25 205 1660 665 March 20 210 1420 670 April 15 215 1180 675 May June 180 2860 640 Total: 160 1220 From Excel File: Ch12_Bottomup.xls ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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… and Load Profile for Assembly
©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Smoothing Production in April, May, and June . . .
Bill of Labor CSEs Home Gyms Assembly 50 2 Painting 3 Hours of Month Max. Max January 30 200 1900 2200 660 750 February 25 205 1660 665 March 20 210 1420 670 April 215 1680 695 May 1920 690 June 180 1860 600 Total: 160 1220 NOTE: Total production over the six months isn’t changing, just the timing ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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… and the New Load Profile
©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Options for Services Smooth out demand: Tiered workforce:
Appointments Discounts and promotions Seasonal complements Tiered workforce: Full-time and part-time Customer involvement Minimize on-line activities ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Self-Test Go into SOP.xls and try to develop a aggregate production plan with lower costs than either the pure chase or pure level strategies. Do this by varying the actual workforce in place, making sure you keep inventory levels above 0 at all times. Suppose firing and hiring costs were to double while inventory holding cost per unit was cut in half. How do you think this would affect the relative attractiveness? ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Advanced Topic: Optimization Modeling
What is optimization modeling? Essential conditions Application to operations problems ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Optimization Modeling
Family of mathematical techniques used to allocate limited resources among competing demands in an optimal way What is our financial objective? What are our constraints? ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Optimization Example 1 Product mix: Find the product mix that will maximize revenue, given limits on materials, labor hours, and machine hours available ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Optimization Example 2 SOP: Find the workforce and inventory levels which will minimize hiring, firing, and inventory costs while still meeting demand. ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Optimization Example 3 Transportation Problem: Minimize the cost of shipping items from different plants to different stores ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Optimization Example 4 Material Yield: Minimize the amount of scrap generated by cutting steel, fabric, wood, etc. Scrap Material ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Optimization Essential Conditions I
Explicit objective Maximize revenue or profit Minimize costs 2. Some constraint(s) Resource limits Demand requirements ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Optimization Essential Conditions II
Conditions can be expressed mathematically Revenue = $1000X Variable cost = $310X Assembly hours needed = 15X Divisibility OK to make half a unit or hire two thirds of an individual ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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SOP Optimization Two major types of problems
Maximize profit or revenues subject to resource constraints Minimize costs subject to demand requirements ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Maximization Problem I
CSE: $1000 per unit Home Gym: $150 per unit Labor requirements: Assembly Painting CSE Home Gym ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Maximization Problem II
Hours available per month Assembly 2200 hours Painting 750 hours Sales of home gyms limited to 150 per month ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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In mathematical form: (CSE C, Home Gym H)
Maximize: $1000C + $150H Subject to the following conditions: 50C + 2H < (Assembly hours constraint) 2C + 3H < 750 (Painting hours constraint) H < (Demand limit on home gyms) C, H > 0 (think about it!) ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Bottom Up Plan to Allocate Capacity to Maximize Profits
Before Solving ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Bottom Up Plan to Allocate Capacity to Maximize Profits
and After Solving ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Key Points This is the most revenue we could generate, given the constraints “No slack” assembly time, Home gym demand More painting time or more CSE demand wouldn’t change anything More constraints can only make the problem more difficult, fewer constraints can only help ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Minimization Problem SOP: “Meet the production plan with the minimum total hiring, firing, and inventory cost” Take earlier SOP problem and solve using optimization techniques. Can you figure out how the problem would be defined? ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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Highlight from Optimization Solution
Comparison Costs: Chase Strategy: $197,000 Level Strategy: $205,844 Level Strategy with Subcontracting option: $136,704 Annual Cost = $130,200 (Note: Solution didn’t let inventory go below 200) ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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What to Take Away from this ...
Essential conditions: Explicit objective Constraints Linearity Divisibility Write out an objective function or constraint for simple problem Interpret simple results ©2006 Pearson Prentice Hall — Introduction to Operations and Supply Chain Management — Bozarth & Handfield
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