1 luis ernesto blanco rivero "simulation as a tool for understanding manufacturing"...
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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 TimesSlow downs due to set ups
Scheduled maintenanceTardy arrivals of materials
High Work In ProcessPriorities
Recycles
Defective materials
Tardy arrivalsIncomplete
lotsWrong 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 bottleneckEven 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 ToTo = 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"
Worst Performance Law
THworst = { W/(Wo+W-THworst = { W/(Wo+W-1)}* rb 1)}* rb
CTworst = To + (W-1)/rbCTworst = To + (W-1)/rb
14Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Some Performance Tips
AS WIP INCREMENTS
CT INCREMENTS
TH REMAINS EQUAL OR LESSER
15Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Some Performance Tips
MANUFACTURING PLANNERS
MUST TO KNOW WoWo IT MEANS THEY HAVE TO
KNOW rbrb BECAUSE Wo = rb.ToWo = rb.To
16Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Some Performance Tips
WIP MUST BE A WIP MUST BE A CONTROL CONTROL
PARAMETERPARAMETER
17Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Some Performance Tips
1. TO CONTROL WIP INSTEAD OF TO CONTROL THROUGHPUT
2. TO CONTROL VARIABILITY
18Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Some Performance Tips
MRP SYSTEMS CONTROL THROUGHPUT INSTEAD OF
CONTROLLING WIP MRP IS A POWERFUL
INFORMATION TOOL SOME MRP SYSTEMS TREAT TO CONTROL VARIABILITY
19Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Some Performance Tips
20Luis Ernesto BLANCO RIVERO "SIMULATION AS A TOOL FOR UNDERSTANDING MANUFACTURING"
Some Performance Tips
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