Slide 1 IEM 5303 Advanced Manufacturing Systems Design 2000 John W. Nazemetz Welcome to Week 10...
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Transcript of Slide 1 IEM 5303 Advanced Manufacturing Systems Design 2000 John W. Nazemetz Welcome to Week 10...
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 1
Welcome to Week 10 Discussion
Agenda for Tonight:
Review of Exam
Discussion Questions from Discussion Leaders
Other Questions from Students
Let’s Begin …
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 2
Question 1 --
1. (25 pts.) Do CIM systems that employ Generative Computer Aided Process Planning benefit from the simultaneous use of Group Technology concepts?
Yes/No
Exam Review (1a)
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 3
Question 1 -- cont.
If so, how and/or under what conditions? (25 of 25 possible)
Similar shapes/designs -> similar routings
Operational Efficiencies (families, batching in families – recalculate families each period)
Reduction in part variation, increase volume of common parts
Reduction in tooling with reduction in parts variation, tooling cost with volume increase
Exam Review (1b)
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 4
Question 1 -- cont.
If not, why not (20/25 max available).
Generative CAPP, re-determines routing each time based on technical and economic feasibility so no permanent families established/establishable
BUT -- GT makes designs similar, so algorithmically derived routings are similar and other benefits are derivable.
Exam Review (1c)
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 5
Exam Review (2)
Question 2 --(25 pts.) Define and explain Quality Function Deployment. List
and discuss its weak points. Define and Explain (15 pts.)
Process to document and assess products with respect to an ordered and weighted set of customer requirements, technical specifications, the correlation of customer requirements and technical specifications, comparison to competitors, required quality (tolerances) of part, production methods.
Weaknesses (10 pts.)Ability to gather customer
requirements/competitor dataAbility to translate requirements to specificationsAbility to define correct weights/economicsCan make week analysis “look” stronger than it is
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 6
Exam Review (3)
Question 3 --
Consider the various models proposed in the text and in lecture for developing part families and manufacturing cell groupings. List, briefly define, and evaluate three (3) models/methods for cell and/or family formation (i.e., explain the philosophy/objective of each algorithm/procedure, the steps of each algorithm/procedure, and discuss its strengths and shortcomings). (8 pts each plus 1)
Machine Component Group Analysis
Production Flow Analysis
Rank Order Clustering (King)
GT Coding and Pattern Recognition
Single-Linkage Cluster Analysis - Similarity Coefficients
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 7
Exam Review (4a)
Question 4a --
(17 pts.) Consider Robots and Numerical Control Machines. Explain the similarities and differences between the two.
Similarities Same basic technology, sensors
Similar programming
Similar function (move parts or tools in space)
Similar concepts – open/closed loop, pt to pt, continuous path, multi-axis, multiple tools/parts
DifferencesRobots less precise, accumulate error while NC
more precise, axis error is independent
Robot generally used for ergonomic and economic reasons, NC generally used for technological reasons
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 8
Exam Review (4b)
Question 4 --
(8 pts.) Consider Robots and Numerical Control Machines. Briefly explain the role/use of each in FMS/Cellular Manufacturing under conditions of a) high product (design/shape) variability and low part volume (sales) as well as b) high part volume (sales) and low product (design/shape) variability.
Role – high product variability/low volumeRobot – allows flexibility via general purpose hand,
teach or low-cost/time programming
NC – allows precision manufacturing via reprogramming
Role – low product variability/high volumeRobot – allows labor replacement, repetitive
motions
NC – provides an alternative to custom, single purpose equip.
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 9
Exam Review (5a)
Question 5 --
(25 pts.) Briefly define the life cycle and product concepts of Chris Vaughan. (15 pts.)
Life Cycle Concepts:
Design, Produce, Operate, Service, Dispose
All products have this life cycle
Iterative process (Less -> More detailed)
Applies across Supply Chain (all Levels)
Product Concepts:
Almost everything is a product
Products interact (Operate facility (product of “design and produce facility” is produces product
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 10
Exam Review (5b)
Question 5 --
(25 pts.) Briefly define the life cycle and product concepts of Chris Vaughan. Comprehensively discuss how his definition/concepts apply/do not apply in the practice of Concurrent Engineering. (10 pts.)
Phases of life cycle define major inputs to concurrent engineering (design must consider production, operation, service and disposal of product)
Iteration of design Design document(s) (product) –
output/input of design facility, iterates from conceptual design to “final” design to redesign to re-redesign, …
Stages of design correspond to (design) supply chain
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 11
Discussion Questions (Jeff Short)
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 12
Discussion Questions (Jeff Short)
What is the difference between JIT, MRP, and Lean Manufacturing?JIT – minimum (zero) inventory goal
Absorbs fluctuations/disruptions via excess capacity (labor and machines)
MRP – maximize utilizationAbsorbs fluctuation by planning/scheduling
Lean Manufacturing – a manufacturing philosophy of efficiency which, when implemented, shortens the time between customer order and factory shipment by eliminating waste. "Uses less of everything compared with mass production”
Focus on efficiency/productivity of process
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 13
Discussion Questions (Jeff Short)
Chapter 10 is about MRP and Chapter 11 is concerned with JIT. These seem to be diametrically opposed views of production planning and control. What is the current state of research to resolve the philosophical disagreements and reach a more practical operating philosophy?
Diametrically opposed in theoretically pure form –In practice, they blend –
Balance ability to predict and preplan fluctuating vs. constant stable system (production, customer, …)
No smooth/known demands (Seasonality, competitors)
No smooth production (machine/managerial breakdown)
No 100% availability (temporary demand exceeding capacity, rush orders)
Inventory to deal with unexpectedResearch using each method criteria (utilization/inventory)
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 14
Discussion Questions (Jeff Short)
Can JIT exist in practice for a manufacturer with high variance in demand?
Yes, but if variance in demand is high, a large amount of excess production capability must be available to meet demand (on-time). As this cascades through a system, more interchangeable, cross trained workers needed with resultant higher labor costs.
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 15
Discussion Questions (Jeff Short)
I understood the Wagner and Whitin Algorithm produced this property: either the inventory carried to period t+1 from period t must be zero or the production quantity in period t+1 is zero.
Question 6 asks the student to begin with an inventory, obviously a violation of the W-W algorithm. I felt there were several ways to deal with this problem, all of which modified the algorithm. Which way would you suggest?Reduce demand in first period(s) to reduce inventory to
zero.Is there a stochastic or fuzzy representation of the W-W
algorithm??Yes, simulation/modified Newsboy problem
“goodness of solution” is determined by ability to predict period demands/distribution of demand.
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 16
Discussion Questions (Jeff Short)
Both W-W and Naidu & Singh treat the variable of h, holding costs, as a well-know entity. I have never worked for/with a company that could fix the value of h for any product under all storage conditions. How is h handled in your experience?
Via “Best Estimate” UsageV = value of part/product ($)
h = V x (interest rate +inflation rate + insurance rate + spoilage rate + pilferage rate + management rate)
+ Size x (cost of space)
All rates in ($/$inv), Cost of Space in $/unit volume
Can stratify inventory (Pareto-type Analysis)
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 17
Discussion Questions (Mike Blanton)
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 18
Discussion Questions (Mike Blanton)
Problem 10.7 was difficult to do. It followed example 10.4 which was continued from example 10.3. The examples seemed to leave information out, under the assumption that they were easy to follow. For me and I assume other students this was not the case. Could you please fill in the blanks.I’ll try on the next slides.
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 19
Discussion Questions (Mike Blanton)
In example/problem, an LP model is solved.
For 10.7 –
One must first calculate the demand (dt)In period one dt = 50 + 60 + 70 + 80 = 260
units
In common units Xt = 2(50+70) + (60+80) =
380 hours
This will mean k = 1 hour/unit for 380 units
Perform similar calculations for other periods.
Then set up LP problem:
tfthtstitutotwtx FcHcIcIcUcOcWcXcMin
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 20
Discussion Questions (Mike Blanton)
Subject to
With Wo=240, k=1
d1=380
All 0 subscripts dropped
Non-negativity
tttttttt FHIIUOWXMin 40245005604024120
tttt
tttt
tttttt
WkXUO
FHWW
IIIIXd
1
11
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 21
Discussion Questions (Class)
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 22
Discussion Questions (Class)
Other Questions as raised
IEM 5303Advanced
Manufacturing Systems Design
2000 John W. Nazemetz
Slide 23
Discussion Session 10
End of Class
Have a Good Week and I’ll see you next time!