MFGT 124
Solid Design in Manufacturing
Chap 1: Moments of Inertia
Professor Joe Greene
CSU, CHICO
Reference: The Mechanical Process, 3rd Edition, David Ullman,
McGrall Hill New York (2003)
MFGT 124
Copyright 2003 Joseph Greene All Rights Reserved
1
Chap 1: Design Process
• Objectives
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–
–
–
Introduction
Measurements
History
Life of a Product
Solutions
Actions
Knowledge
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Why Study Design Process
• Introduction
• Measuring the Design Process with Product Cost, Quality,
and Time to Market
• History of Design Process
• Life of Product
• Solutions for Designs
• Basic Actions of Problem Solving
• Knowledge and learning During Design
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3
Introduction
• Humans have been designing items for nearly 5000 years.
– Parts are designed with a process that can be complex.
• Gearboxes, heat exchangers, computer chips, automobiles, bikes, satellites, decks,
houses, etc..
– Parts can be designed with “seat-of-the pants” process (Make it as you go) or
with a particular process.
– Without a mechanical design process, the cost to manufacture is too high, the
quality is too low, and the time to make the product is too high.
• 85% of the problems with new products are the result of a poor design.
– Not working as they should
– Costing too much
– Taking too long to develop.
• Improvements to the design process saves time and money.
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Introduction
• Concurrent Engineering http://www.soce.org/
– Have many disciplines involved in the design process.
• Engineering, Manufacturing, Marketing, Quality, Customers
– Concurrent Engineering:
• Systematic approach to the integrated design of products and their related processes,
including manufacture and support.
– The concurrent engineering approach causes developer
• To consider all elements of the product lifecycle from concept through disposal,
including quality control, cost, scheduling and user requirements.
– Benefits of Concurrent engineering include
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Less development time,
Fewer engineering changes,
Less time to market,
Higher quality, and
Higher white collar productivity.
– Society of Concurrent Engineering is an open organization with 4 chapters:
•
•
•
•
Boston
San Diego
Silicon Valley, and
Quebec
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Introduction
• Components of Concurrent Engineering
– Business Plan
• Idea and Identifiable Need
– Define general shape and use
• Target Customer/Market
– Benchmark cases of similar products
• Forecast
– Sales Volume (How many parts per year can be sold), Distribution channels
– Cost and Risk Assessment for legal, environmental, governmental issues
– Promotional Plan for TV, Radio, Print
• Return on Investment (Most projects need at least 5% ROI)
– Product Design
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Definition of form (what does it look like) and function (what is it suppose to do)
What are typical materials and suppliers
What are high level performance requirements (MPG, horsepower, crash tests, etc..)
What are Product Quality targets (Fit and finish, exterior image)
– Production Systems
• What plants can make product
• What are Process Quality targets (scrap %, per part manufacturing costs, cycle time)
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2003 Joseph Greene All
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• What manufacturing
equipment/machines
are
required.
Build or Buy parts.
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Concurrent Engineering Example
• New Car for Chevy Camaro
– GM Product Development Team (PDT) Meet weekly with upates
• Cross functional team made up of people from engineering, sales, marketing,
manufacturing, quality, business.
– Business Plan
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•
•
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160,000 cars per year sold
Baby boomer male 35 to 55 yrs old
Mustang and Monte Carlo SS package
ROI is estimated to be 5%, break even point 15 months
– Product Design
30K
25K
$ 20K
15K
10K
SUV
Crowne Vic
Seville
Mustang
Cimmeraon
Delta 88
Monte Carlo
Grand
AM
Focus Saturn
Sprint Escort
Small
Midsize
Big
Size of Car
• Rear wheel drive sports car, updated classic design
• Use old frame, new transmission, new engine, new body panels, share with Pontiac
the transmission, engine, and doors, others are new
• Break car design into 8 different systems and designate a design chief for each
section
– Production System
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New engine, body panel assemblies, and powertrain.
Use existing plant in Canada for Chevy and Pontiac
Layout manufacturing process into 6 major sections, $250M manufacturing cost
Estimate manufacturing
of $12,000
overhead
and profit
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2003 Joseph
Greeneplus
All Rights
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Measuring Design Process
• Product Cost, Quality and Time to Market
– The three measures of the effectiveness
• Cost
• Quality
• Time to market
– All three measures are vital whether the product is the whole
system (the car) or a subsystem (the powertrain) or a sub
component (the engine)
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30
– Mfg Cost of an automotive part
Manufacturing Cost of Automotive Part
• Design is smallest part but
– Influences the rest
Overhead
50
Labor
Material
Design
15
• The other costs are higher often due to design changes
• Results of the design process can change the cost of the manufactured
product by 50% (+/- 25%)
• Xerox attributes 50 % of the final cost to the deign process
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Cost Drivers (what influences cost)
• Engineering changes during the automobile development causes
higher costs, lower quality, and more time to produce
Company A
– Figure 1.6
Design
Changes,
And Cost $$
Lower
Costs
Design
Higher
CompanyCosts
B
Production
• Costs are higher the later in time changes happen.
Starts
Timing
• Company A (Toyota)
– Sets aside a large number of design engineers and $$ early in design process.
– Results in fewer design changes later
» Reduced costs later and improved quality.
• Company B (GM)
– Sets aside a minimum number of design engineers and less $$ early in design
process. Provides
– Results in many design changes later
» Higher costs later and lower quality.
– Suppliers quote jobs at a very low price but then charge the company large $$$
for changes to their part when the company changes the design.
» Troy Engineering quotes injection mold for $200,000 and then charges
company
$250,000
for changes
later
in the
program after changes.
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2003 Joseph
Greene All
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Quality and Timing
• Engineering changes during the automobile development causes
higher costs, lower quality, and more time to produce.
Line Fallout at Xerox
– Xerox Quality Study
Defects per 1000
• Fig 1.5
35
30
25
20
15
10
5
0
1982
1984
1986
1988
1990
1992
1994
Year
• Number of parts that fall-out or are rejected
• Competitors had much less rejects per 1000 pieces
• Xerox was losing business due to poor quality
– Restructured design process to make changes earlier in design process
– No changes once design was frozen
– Reduced time from concept to production from 3 years to 6 months
– Reduced scrap rate and improved quality
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History of the design process
• History of the design process
– Cradle to grave
• Design: Concept starts process where the idea begins
• Development process occurs to develop idea into engineering and manufacturing
terms
• Manufacturing: Production process takes development data and makes thousands of
the same part per day.
– Simpler times
• One person could design and manufacture entire product.
– Parts were simple, regulations were few, quality was fair
– Current times
• Products are more complex.
• Companies separated the different areas into different organizations
– Design, Manufacturing, Quality, Production, Sales didn’t communicated very
well
• Over the wall design method where different departments don’t share ideas.
– Design gives Manufacturing the design without Mfgt input
– Manufacturing gives tools and layout to Production without input
• Results in poor design with large quality issues and late
Customers
Marketing
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Design
Mfgt
Production
Customers
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History of the design process
• GM example
– Glory years 1950s to 1980s
– GM Organization
• Centralized Engineering and Manufacturing into Fisher Body
– All cars were designed and manufactured by Fisher Body
» Information for common parts were shared between Chevy,
Pontiac, Buick, Oldsmobile, Cadillac.
» The designs were very similar because the same engineering team
designed them.
• Centralized Production
– All cars were produced by GM Assembly Division
» The assembly plants were laid out very similarly and information
was shared amongst car lines
• Independent Sales Divisions were responsible for sales of cars and trucks.
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History of the design process
• GM example
– Terrible Years under Roger Smith (mid to late 1980s)
– GM Organization
• Separated Engineering and Manufacturing and Production
– All cars were designed and manufactured by each car division
» Small Car: Information for common parts were shared between Chevy,
Pontiac and GM of Canada. Had separate design standards for car.
» Midsize and Large Car - Information for common parts were shared
between Buick, Oldsmobile, Cadillac.
» The designs became different though the function was the same for
exterior parts, powertrain, structrures because the different engineering
team designed them.
– All cars were produced by each division separately
» The assembly plants were laid out very different and information was not
shared amongst car lines
– GM Truck had centralized design and manufacturing organization. Big profits
– Result was a financial disaster
• GM lost $10 billion in 4 years.
• The cost to product a car at GM was twice as much as Honda and 50% more than
Ford.
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– Roger Smith was fired
and a Movie was made “Roger and Me”
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History of the design process
• GM example
– Great Years under Richard Wagoner mid 1990s to current
– GM Organization
• Centralized Engineering
– All cars were designed by GM Engineering
» Information for common parts were shared between Chevy, Pontiac,
Buick, Oldsmobile, Cadillac.
» The designs were very similar because the same engineering team
designed them.
» Developed one common design standards and layouts for all cars and
trucks.
• Centralized Manufacturing and Production
– All cars were produced by GM Manufacturing Division
» The assembly plants were laid out very similarly and information was
shared amongst car lines
• Independent Sales Divisions were responsible for sales of cars and trucks.
– Result was a financial winner
– No longer had over-the wall designs.
• Concurrent engineering was the method of organization.
– Each product
team would
haveGreene
representatives
from design, manufacturing,
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2003 Joseph
All Rights Reserved
production, quality, sales and marketing.
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History of the design process
• Key Features of Concurrent Engineering
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Focus on entire product life (Chap 1)
Use and support of design teams (Chap 3 and 5)
Processes are as important as product (Chap 4 and 5)
Good project planning and management (Chap 5)
Development of product requirements (Chap 6)
Multiple concept generation and evaluation (Chap 7 and 8)
Decision making process (Chap 8)
Concurrent development of product and mfgt process (Chap 9-13)
Effective communication
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Life of Product
• Every phase of the development is the life of product
– Figure 1-8
• Product development
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Identify need
Plan for the design process
Develop engineering requirements
Develop concepts
Develop product
• Production and delivery
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Manufacture
Assemble
Distribute
Install
• Use
– Customers
• End of Life
– Retirement
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Many Solutions for Design Problems
• Example, analysis problem
– What size SAE grade 5 bolt should be used to fasten together 2
pieces of 1045 sheet steel each 4 mm thick and 6 cm wide, which
are lapped with 100 N?
•
•
•
•
Need is very clear
Problem is understood
No need to design the joint since it is already spec’d
Only decision to make is to determine if the specs are OK
• Typical design problem
– Design a joint to fasten together two pieces of 1045 steel each 4
mm thick and 6 mm wide, which are lapped over each other and
loaded with 100N
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Similar to first problem and easier to understand
Don’t need to know how to design for shear failure of bolted joints
Much more latitude in engineering design due to less constraints
Other questions come up for type of environment, disassembly,tools
available, cost, mating equipment and tools, etc…
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Many Solutions for Design Problems
• Some problems are ill defined.
– Too few constraints or information
– Too much constraints or information
• Typical design problems have multiple solutions
– Some bad solutions
– Some good solutions
– A few optimum solutions
• Lowest cost
• Highest performance
• Fastest time
• Fig 1.10
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Problem Solving
• Basic Actions
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Establish the need or realize a problem needs to be solved
Plan how to solve the problem
Understand the problem by developing requirements
Generate alternative solutions
Evaluate the alternatives
Decide on acceptable solutions
Communicate the results
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Knowledge and Learning
• Capturing lessons learned
– When design process starts little is known about the solution
– As the design and manufacturing process develops
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•
•
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New ideas and solutions to problems are identified
Knowledge is gained by the development team
Technologies are further defined and developed
New ways and innovation
– At the end of the project a lot is known about the solution and the hurdles that
were overcome to achieve results
– The information needs to be documented before the development team dissolves
and people reassigned so that the information can be used on the next program
– Example,
• GM used knowledge based computer programs that were added to design packages
so that best practices can be used in each car or truck program.
– Fig 1.11 Design process paradox
– Exercises 1.2, 1.4
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