1 luis ernesto blanco rivero "simulation as a tool for understanding manufacturing"...
DESCRIPTION
3 Luis 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 VariabilityTRANSCRIPT
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