1 product mix & master production scheduling. 2 product mix problem quantity of each of multiple...
TRANSCRIPT
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Product Mix &Master Production Scheduling
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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
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Linear Programming (L.P.)
Continuous Decision Variables
Decision Variable Subject to Constraints
Objective Function that is Maximized or Minimized
Equations or Inequalities are Linear
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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.
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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
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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
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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
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MPS Differs from Production Plan
Shorter Time Buckets
Used for Each End Item Not Families of Items as in Production Plan
Generally More Detailed
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Items in MPS Must Add Upto What’s in Production Plan
WEEK 1 2 3 4 5 6
UNICYCLES 100 50 50 40
BICYCLES 100 100 40
TRICYCLES 50 50 20
TOTAL - Production Plan 100 100 100 100 100 100
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What “End Items” Go into MPS
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MPS Can Show Running Inventory
Made to Stock Only
WEEK 0 1 2 3 4 TOTAL
FORECAST 200 300 100 100 700
AVAILABLE 200 250 200 100 100
MPS 250 250 100
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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
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MPS with Minimum Available of 100
WEEK 0 1 2 3 4 TOTAL
FORECAST 200 300 100 100 700
AVAILABLE 200 250 200 100 100
MPS 250 250 100
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MPS and Capacity
Made to Stock
(Two Hours per Bike; Three Hours per Trike)
WEEK 1 2 3 4 5 6
BIKES 10 20 30 20 40 0
TRIKES 20 10 20 10 0 30
TOTAL HOURS 80 70 120 70 80 90
CAPACITY 100 100 100 100 100 100
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ATP (Available to Promise)
Portion of Inventory Not Committed – Available to Customer
ATP = Scheduled Receipts + Beginning Inventory - Actual Orders Scheduled
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ATP Calculation
On Hand:100
ATP (1) = 100 – 80 = 20 ATP (2) = 100 – (10+10) = 80 ATP (4) = 100 – 30 = 70
WEEK 1 2 3 4 5 6
CUSTOMER ORDERS 80 10 10 30
MPS 100 100
ATP 20 80 70
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