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Product Mix & Master Production Scheduling. Product Mix Problem. Quantity of Each of Multiple Products to Produce - Example: How Much of Various Flavors of Ice Cream to Produce? Solution Methods - Hueristics - Linear Programming. Linear Programming (L.P.). Continuous Decision Variables
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Product Mix Problem • Quantity of Each of Multiple Products to Produce - Example: How Much of Various Flavors of Ice Cream to Produce? • Solution Methods - Hueristics - Linear Programming
Linear Programming (L.P.) • Continuous Decision Variables • Decision Variable Subject to Constraints • Objective Function that is Maximized or Minimized • Equations or Inequalities are Linear
Consider the Following: The businessperson, Cindy Light, publishes two magazines, Paygirl (for men) and Payboy (for women). Monthly sales average about 6,000 and 4,500 issues respectively for the publications. Paygirls contribute $.60 per issue to net profits; Payboys add about $.50 per issue. No left over magazines are desirable. Each Paygirl requires two minutes of actual machine and labor time to produce. Payboys only require one minute. There are 10,000 total minutes per month of time available. Inventory storage space imposes another limitation. 48,000 cubic inches are available and each magazine uses up about 8. Determine monthly production for each magazine.
E.g. L.P. Formulation • X1: Issues of Paygirl X2: Issues of Payboy • Objective Function: Max. Z = .6 X1 + .5 X2 • Subject to (s.t.): 2 X1 + X2 10,000 (Labor) 8 X1 + 8X2 48,000 (Inventory) X1 6,000 (Demand) X2 4,500 (Demand) X1, X2, 0
Linear Programming (L.P.) • We Can Use the Computer (Simplex Method Using POM for Windows) to Find the Answer. • The Answer Would Be Incorporated in the Master Production Schedule
Master Production Scheduling (MPS) • Link between Production Planning and What is Built or What Service is Performed • Used for Calculating Resource and Capacity Needs • Drives Material Requirements Plan (MRP) • Keeps Priorities Valid – Is Negotiated Agreement
MPS Differs from Production Plan • Shorter Time Buckets • Used for Each End Item Not Families of Items as in Production Plan • Generally More Detailed
MPS Can Show Running Inventory Made to Stock Only
Optimizing MPS • Develop Preliminary Plan • Maintain Desired Customer Service by Optimizing Available Goods • Make Best Use of Resources (Materials, Labor, Equipment) • Check Preliminary Plan Against Capacity • Resolve Differences Between MPS and Capacity
MPS and Capacity Made to Stock (Two Hours per Bike; Three Hours per Trike)
ATP (Available to Promise) • Portion of Inventory Not Committed – Available to Customer • ATP = Scheduled Receipts + Beginning Inventory - Actual Orders Scheduled
ATP Calculation On Hand:100 • ATP (1) = 100 – 80 = 20 • ATP (2) = 100 – (10+10) = 80 • ATP (4) = 100 – 30 = 70