1 Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING" Information flow Manufacturing Operation As A Single System OPERATION OPERATION OUTPUT OUTPUT (PRODUCTS) (PRODUCTS) INPUT INPUT (RAW MATERIALS) (RAW MATERIALS) CONTROL
Manufacturing Operation As A Single System. OPERATION. OUTPUT (PRODUCTS). INPUT (RAW MATERIALS). CONTROL. Information flow. Manufacturing Operation As A Single System. LITTLE`S law: TH=WIP/CT. OPERATION. THROUGPUT (Products/Time). WORK IN PROCESS (Units of RAW MATERIALS). - PowerPoint PPT Presentation
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1Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Information flow
Manufacturing Operation As A Single System
OPERATIONOPERATION
OUTPUTOUTPUT(PRODUCTS)(PRODUCTS)
INPUTINPUT(RAW MATERIALS)(RAW MATERIALS)
CONTROL
2Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Information flow
Manufacturing Operation As A Single System
OPERATIONOPERATION
THROUGPUTTHROUGPUT(Products/Time)(Products/Time)WORK IN PROCESSWORK IN PROCESS
(Units of RAW MATERIALS)(Units of RAW MATERIALS)
CONTROL
CYCLE TIME (Time)CYCLE TIME (Time)
LITTLE`S law: TH=WIP/CTLITTLE`S law: TH=WIP/CT
3Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Sources Of Variability In A Single Operation
Machine Failures
Shut downs due to quality problems
Operator´s Off Times
Slow downs due to set ups
Scheduled maintenance
Tardy arrivals of materials
High Work In Process
Priorities
Recycles
Defective materials
Tardy arrivals
Incomplete lots
Wrong lots
VariabilityVariability
4Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Parameters And Variability Interrelationships
WIPWIP
THTH
CTCT
WoWo
VariabilityVariability
5Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Parameters And Variability Interrelationships
6Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Dependency Phenomenon
2
3
4
1 5Raw materialsRaw materials End ProductsEnd Products
MostDependentOperation
7Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Variability And Dependency Phenomenona Affect:
THROUGHPUT (TH)
WORK IN PROCESS (WIP)
CYCLE TIME (CT)
VARIABILITYVARIABILITY DEPENDENCYDEPENDENCY
8Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Bottleneck Effect
1 2 3
r1 r2 r3
r1 = min (r1,r2,r3) is the bottleneck
Even if W increases as infinite,
TH is TH is maximummaximum r1 r1
ri = Production rate (parts/unit time)ri = Production rate (parts/unit time)
9Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Bottleneck Effect
10Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Global Processing Time:To
1 2 3
t1 t2 t3
Global Processing Time To
To = t1 + t2 + t3To = t1 + t2 + t3
ti = Production time (time per unit)
11Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Critical Wip:Wo
To = Global To = Global Processing Processing
TimeTime
Wo = (rb). Wo = (rb). ToTo
rb = rb = bottleneck bottleneck
raterate
12Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Best Performance Law
W/ToW/To, if W < Wo or W =Wo rbrb, otherwise
ToTo, if W < Wo or W =Wo W/rb, otherwiseCtbest =
Thbest =
13Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"