MODELING AND ANALYSIS
OF
MANUFACTURING SYSTEMS
Ernesto Gutierrez-Miravete
ernesto@rh.edu
RENSSELAER AT HARTFORD
http://www.rh.edu/~ernesto/C_S2001/mams
PURPOSE OF
MANUFACTURING
• TO INCREASE SHAREHOLDER VALUE
• TO SATISFY CUSTOMER WANTS AT
MINIMUM COST
• TO ENRICH SOCIETY THROUGH THE
PRODUCTION OF QUALITY, LOW
COST PRODUCTS WITH MINIMUM
IMPACT ON THE ENVIRONMENT
MANUFACTURING SYSTEM
FUNCTIONS
• PRODUCT DESIGN
• PROCESS PLANNING
• PRODUCTION OPERATIONS
(FABRICATION & ASSEMBLY)
• MATERIAL FLOW/FACILITIES LAYOUT
• PRODUCTION PLANNING/CONTROL
• ADMINISTRATIVE
PURPOSE OF MODELING
• TO HELP IMPROVE MANUFACTURE
SYSTEM DESIGN.
• TO HELP PREDICT MANUFACTURING
SYSTEM PERFORMANCE.
• NOTE: GOOD MODELING
REQUIRES GOOD DATA!
MANUFACTURING SYSTEM
TYPES
• PRODUCT LAYOUT
– Products move sequentialy along the same flow
line
– Examples: Assembly and Transfer Lines
• PROCESS LAYOUT
– Products move sequentialy visiting different
workstations according to a plan
– Examples: Job Shops
MANUFACTURING SYSTEM
TYPES (contd)
• CELLULAR (GROUP) LAYOUT
– Similar parts are grouped together to justify
their own machines
– Roughly a hybrid of Process and Product
Layouts
• FIXED POSITION LAYOUT
CHARACTERISTIC
FEATURES OF LAYOUTS
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THROUGHPUT TIME (T)
PRODUCTION RATE (P)
WORK IN PROCESS (WIP)
SKILL LEVEL
PRODUCT & DEMAND FLEXIBILITY
MACHINE UTILIZATION
UNIT PRODUCTION COST
Question
• How does the number of Parts per Hour vs.
Number of Part Types vary with Layout
type?
“LAWS” OF
MANUFACTURING
• Little’s Law
WIP = P*T
• Mass and Energy are
Conserved
• Larger Systems are
Less Reliable
• Law of Material
Decay
• Complexity Growth NM
• Technology Changes
• Randomness of
Behavior
• Limits of Rationality
• Combine, Simplify,
Eliminate to produce
Savings
MANUFACTURING MODELS
• EFFICIENCY VS. EFFECTIVENESS
• PHYSICAL MODELS
• ANALYTICAL MODELS
– PRESCRIPTIVE
– DESCRIPTIVE
• EXPERIMENTAL MODELS
– SIMULATION MODELS
• HYBRID MODELS
HEURISTIC APPROACH
• AN ATTEMPT TO FIND A GOOD (i.e.
NEARLY OPTIMAL) SOLUTION TO A
PROBLEM BY USING A RATIONAL
METHOD.
• HOW TO SELECT WHICH
INFORMATION TO IGNORE?
• HEURISTICS VS. OPTIMIZATION
MODEL USES
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OPTIMIZATION
PERFORMANCE PREDICTION
CONTROL
INSIGHT
JUSTIFICATION
MARKETING TOOLS
MODEL DEVELOPMENT
• PROBLEM DEFINITION
• DETERMINATION OF RELEVANT
INFLUENCING FACTORS
• MODEL BUILDING
• VERIFICATION
• VALIDATION
ASSIGNMENT
• READ
– CHAPTER 1 AND SEC 2.1 IN A&S
• BROWSE AND EXAMINE
– CHAPTERS 11, 12 AND 13 IN A&S
• HOMEWORK
– PREPARE FOR CLASS PRESENTATION
THE SOLUTION OF ONE PROBLEM AT
THE END OF CHAPTER 1