文档介绍：Material Management
Class note # 5b
~ Time Costing Method in PSD Decision ~
Prof. Y. Peter Chiu
3 / 2003
1
§. P 1: Introduction to PSD decision
■ Product Structure Diagram :
◇
Trumpet
( End Item )
Bell assembly (1)
Lead time = 2 weeks
Valve casing
assembly (1)
Lead time = 4 weeks
Valves (3)
Lead time=3 weeks
Slide assemblies(3)
Lead time = 2 weeks
2
§. P 1: Introduction to PSD decision
■ Key considerations:
◆ supplier’s Lead time
◆ supplier’s Yield rate
◆ supplier’s Unit cost (price)
■ Key methodologies:
◆ Critical path method (CPM)
- to find the critical path activities, and total pletion time
◆ Time costing method
- to analyze the trade-off between supplier’s lead time and the adjusted unit cost, and to search for the optimal suppliers selection alternatives
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§. P 2: Demonstration
◇
■ Naming Activities
4
§. P 2: Demonstration
■ Obtaining the Critical Path for Trumpet Example (by CPM )
5
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§. P 2: Demonstration
6
◇
§. P 2: Demonstration
■ Notation:
PSD product structure diagram, refers to the relationship between ponents at adjacent levels of the system, containing quantity and lead time information.
i ith level of the PSD
j jth activity of the PSD
Aij jth activity (or refers to manufacture or purchase the ponent or part), in level i of the PSD
Nij quantities required ponent (or part) produced in Aij, to form one unit of the end product (as described by PSD)
Cijn unit cost required by the nth supplier plete activity Aij
Lijn lead time required by the nth supplier plete activity Aij
Yijn yields of the nth supplier when selected to provide activity Aij
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■ Notation:
PC production cost per end item
TPCT total pletion time
Sijn the nth supplier selected plete activity Aij
B estimated benefit (saving) per unit TPCT reduction
(CI)ijn cost increase per unit TPCT reduction, by selecting nth supplier to replace current solution for activity Aij
(CBR)ijn cost/benefit ratio per unit TPCT reduction, by selecting nth supplier to rep