Production Scheduling for the McGuiness & Co. Microbrewery

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Transcript Production Scheduling for the McGuiness & Co. Microbrewery

Production Scheduling for the McGuiness & Co. Microbrewery

A Production Planning & Control Framework

Tactical Planning

Demand Forecasting Production Scheduling Capacity Planning Material Requirements Planning

Execution

Sales order Processing

Recording

Purchasing Inventory records Production Control Shop-floor data Collection

The Production Scheduling Problem

Capacity Consts.

Company Policies Product Charact.

Economic Considerations Placed Orders Forecasted Demand Current Inventory Positions Already Initiated Production

Production Scheduling

Master Production Schedule: When & How Much to produce for each product Planning Horizon Time unit Capacity Planning

Problem Specialization for McGuinness Microbrewery Case Study

• Capacity Constraints: Number and capacity of fermentors • Company Policies: – Product cannot be shelved for more than 2 months – Production in a fermentor can be started at any level of its capacity.

• Product Characteristics: – Production lead times • Economic Considerations: (Unnecessary) Inventories should be minimized (consistent with the Just-In-Time philosophy) • Planning Horizon: 6-12 months (based on production lead times, product seasonalities, and product obsolescence) • Time unit: 1 week (based on the order of production lead times)

Possible Approaches • Empirical Approach:

Spreadsheet-based Simulation

• Analytical Approach:

Mathematical (Integer) Programming formulation

The Driving Logic for the Empirical Approach

Demand Availability: •Initial Inventory Position •Scheduled Receipts Compute Future Inventory Positions Net Requirements Future inventories Scheduled Releases Lot Sizing Resource (Fermentor) Occupancy Product i Feasibility Testing Schedule Infeasibilities Master Production Schedule Revise Prod. Reqs

Example: Implementing the Empirical Approach in Excel

Microbrewery Performance Week # Fermentors Req'd Feasible Loading?

Min # Fermentors Req'd Fermentor Utilization Total Spoilage # Fermentors: 1 0 1 0 2 0% 0 Pale Ale Week Demand Scheduled Receipts Fermentors Released Inventory Spoilage Inventory Position Net Requirements Batched Net Receipts Scheduled Releases Fermentors Seized Total Fermentors Occupied 100 Fermentation Time: 0 1 45 200 1 255 Stout Week Demand Scheduled Receipts Fermentors Released Inventory Spoilage Inventory Position Net Requirements Batched Net Receipts Scheduled Releases Fermentors Seized Total Fermentors Occupied Fermentation Time: 150 0 1 35 115 Unit Cap: 2 0 2 0% 0 2 2 50 3 2 205 40 75 200 3 0 2 0% 0 3 3 40 165 30 45 4 0 2 0% 0 4 4 40 125 30 15 Shelf Life: 20 5 0 2 0% 0 5 5 40 85 40 -25 25 6 0 2 0% 0 6 6 40 45 40 -40 40 7 0 2 0% 0 7 7 40 5 40 -40 40 8 0 2 0% 0 8 8 40 -35 35 40 -40 40 9 0 2 0% 0 9 9 40 -40 40 50 -50 50 10 0 2 0% 0 10 10 40 -40 40 50 -50 50

Computing Inventory Positions and Net Requirements

Inventory Position: IP i = max{IP i-1 ,0}+ SR i +BNR i -D i (Material Balance Equation) (IP i-1 ) + i D i SR i +BNR i IP i Net Requirement: NR i = abs(min{0, IP i })