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Unformatted text preview: cts in equal amounts, for reasons explained below. For example, if the forecast production volume one year from now is 1000 WGR (“weekly going rate”; = good wafers out per week), and the model consists of ten products, then the model is run at 1000 WGR, with a product mix of 100 WGR for each product. After the run, the capacity software is used to generate a worksheet showing the percentage of each tool group’s utilized production capacity required for each product (a tool group is a set of interchangeable tools). Since the model is run with equal numbers of all products, tool groups that are loaded equally per product will see identical loading (10% per product in the above example). Figure A shows a portion of this worksheet for a simplified sample case involving three products at 300 WGR total volume.
Tool Group X X X X Y Y Y Y Z Z Product A B C Totals A B C Totals A Totals Allocation Percent 25.8 33.7 40.5 100.0 27.2 40.8 32.0 100.0 100.0 100.0 as a potential capacity constraint. Though a tool loaded less than 100% is technically not a constraint, companies typically plan to buy an additio...
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This note was uploaded on 04/11/2011 for the course ECE 357 taught by Professor Subjolly during the Spring '11 term at National University of Ireland, Galway.
- Spring '11