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12 Wrapping Up the Design Process and Supporting the Product
Prepare specifications
File with patent office • Title of invention
• Abstract • Drawings
• Background of invention • Summary of invention
• Description of drawings • Claims
Application allowable
Objection or rejection
Submit specifications with oath that invention is original
and with filing fee.
When application accepted, use term “Patent applied for.”
Objections to documentation Objections to specifications
Rejection of claims Applicant
amends application
in response. Review by
patent office
Notice of allowance Payment of fee
Issuance of patent Figure 12.4
Patent application procedure.
the content of the claims. Since the claims define the invention, they are the heart of the patent. All the other information is there simply to support
the claims. After the applicant and the patent examiner agree on the application, the patent
office issues a notice of allowance. This means that the patent will be issued on payment of an issue fee. About 65 of the patents applied for are ulti-
mately granted. Virtually all of these have been greatly modified during the process.
12.6 Design for End of Life
375
Patent Specification
Design Organization: Date:
Title of Invention: Abstract:
Background of the Invention: Summary of the Invention:
Description of Drawings:
Claims:
Attach drawings as needed Notes about filing with the patent office:
Team member: Team member:
Team member: Team member:
Prepared by: Checked by:
Witnessed by: The Mechanical Design Process
Designed by Professor David G. Ullman Copyright 2008, McGraw-Hill Form 27.0
Figure 12.5 Patent Specification.
12.6 DESIGN FOR END OF LIFE
Part of Design For the Environment, DFE, is concern for what to do with a product at the end of its life. This is especially so in the automotive industry,
because there is so much material tied up in 250 million cars and light trucks
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12 Wrapping Up the Design Process and Supporting the Product
Table 12.1 Typical car composition by weight
Material Percentage
Changes in last 15 years
Metals Ferrous
65 Down 7
Aluminum 8
Up 4 Other
4 Plastics
9 Up 3
Rubber 6
Glass 3
Misc 5
registered in the United States and an equal number in Europe. Thus, it is worth looking at efforts to recycle End-of-Life Vehicles ELVs. In the United States,
approximately 12.5 million cars and light trucks are recycled each year. The average composition of these vehicles is shown in Table 12.1. This composition
is changing. In an effort to reduce weight, more aluminum and plastics are now used than there were 15 years ago. The increase in the use of plastics also reduces
manufacturing costs. The basic flow and percentage of materials recovered when recycling an ELV is shown in Figure 12.6. There are fours steps:
1. Dismantling:
This is currently a vehicle-by-vehicle effort at a salvagescrap yard, where a variety of parts and all vehicle fluids and tires are removed.
After removal, the remaining gutted vehicle “hulk” is flattened prior to shipment to the shredding facility.
2. Shredding:
The vehicle hulks are transported to a company that shreds, sep- arates, and processes them. First, a shredding machine takes about a minute
to reduce the hulks to fist-sized pieces.
3. Separation and processing:
The shredded material is separated using mag- nets to attract ferrous metal all iron and steel, except stainless steel away
from all the nonferrous materials both metals and nonmetals. The ferrous material is sent for recycling to steel smelters. The nonferrous material frac-
tion is then typically separated into other metals: aluminum, brass, bronze, copper, lead, magnesium, nickel, stainless steel, and zinc; and into Auto
Shredder Residue ASR or “fluff.” ASR consists of plastics, glass, rubber, foam, carpeting, textiles, and so on.
4. Landfill disposal of ASR:
For the most part, ASR is considered nonrecov- erable waste material and is sent to landfills for disposal.
As the percentage of plastics used in cars and the cost of oil increases, recovering some of the plastics from the ASR becomes more valuable. What makes this
challenging is that there are a wide variety of plastics mixed together in the ASR. Europe is ahead of the United States in its effort to manage ELVs. In an
agreement signed in September 2000, the European Union agreed to
12.6 Design for End of Life
377
Automakers End-of-life vehicles
V ehicles
Dealers Waste
Dismantling Companies
Shredding Companies
Used car dealers,
etc. De-registered
vehicles Users
Users
Sorting Ferrous,
non-ferrous metals Removal
Engines, tires, transmissions, batteries, catalytic converters, etc
Press
20 – 30 20 – 25
50 – 55 Approximately 3 million
tons 2.8 metric tons per year of ASR to landfills:
• 48 plastic • 13 rubber
• 19 glass • 20 other
EU ASR 1.8 metric tons
Figure 12.6 The life cycle of a vehicle emphasizing ELVs.
■
Establish Extended Producer Responsibility EPR for ELV management, requiring manufacturers and importers of autos to pay for the costs of end-
of-life management.
■
Set increased recycling requirements. By January 1, 2006, reuse and recovery minimums were 85 by weight on average. By January 1, 2015, this needs
to be 95 by weight.
■
Establish phase-outs in use of certain heavy metals: lead, mercury, cad- mium, and hexavalent chromium, except in certain excluded components
e.g., lead in lead-acid batteries; hexavalent chromium as a corrosion pre- ventative coating; lead containing alloys of steel, aluminum, and copper;
lead as a coating inside fuel tanks; and mercury in headlamps.
■
Encourage Design For the Environment DFE practices.
■
Code components and materials to facilitate product identification for mate- rial reuse and recovery.
■
Provide dismantling information for every vehicle built. The U.S. government has done little nationally about ELVs, but states such as
California are taking the lead. Additionally, vehicle manufactures are changing both their business model and, to a slower extent, their design practice. Ford
is purchasing recycling operations. DaimlerChrysler has goals to reach 95 recyclability, to reduce the types of materials used by 40, and to increase the
recycled content in their vehicles.
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12 Wrapping Up the Design Process and Supporting the Product
Recovery of materials comes at a cost. First, the vehicles must be trans- ported to the dismantling facility. Then the hulks and removed components must
be transported to the shredders and other processors. Shredding takes about 30 kWhvehicle 375 million kWh per year total and additional energy is needed
to process the shredded material.
To design for the end of life, designers of vehicles and other products need to
1. Design for disassembly.
2.
Label components for easy material identification.
3.
Use fewer different types of materials.
4.
Design products with a longer life span.
12.7 SOURCES
Burgess, J. A.: Design Assurance for Engineers and Managers, Marcel Dekker, New York, 1984. A very complete and well-written book on the development and control of engi-
neering documentation. Guide to Filing A Non-Provisional Utility Patent Application, U.S. Patent and Trademark
Office http:www.uspto.govwebofficespacutilityutility.htm http:ec.europa.euenvironmentwasteindex.htm gives some details on the European
Union’s effort for retiring products Kivenson, G.: The Art and Science of Inventing, Van Nostrand Reinhold, New York, 1977.
Good overview of patents and patent applications; however, it is out of date on application details.
Stevels, Ab: “Design for End-of-Life Strategies and Their Implementation,” Chapter 23 in Mechanical Life Cycle Handbook,
by M. S. Hundal, Marcell Dekker, 2001.
Management of End-of Life Vehicles ELVs in the United States
Staudinger, Jeff, Gregory A. Keoleian, and Michael S. Flynn: “A Report of the Center for Sus- tainable Systems,” Report No. CSS01-01, University of Michigan, 2001, http:css.snre.
umich.educss_docCSS01-01.pdf
End-of-Life Vehicle Recycling in the European Union
Kanari, N., J.-L. Pineau, and S. Shallari: JOM,August 2003, C:\Documents and Settings\D\My Documents\MDP 4th\Chpt 12 Launch\End-of-Life Vehicle Recycling in the European
Union.htm
12.8 ON THE WEB
Templates for the following documents are available on the book’s website: www.mhhe.comUllman4e
■
Engineering Change Notice
■
Patent Specification
A
A P
P E
N D
I X
Properties of 25 Materials Most Commonly Used
in Mechanical Design
A.1 INTRODUCTION
There are literally an infinite number of materials available for use in products. In addition, it is now possible to actually design materials for a specific use. There is
no way a design engineer can have knowledge of all these materials; however, all design engineers should be familiar with the materials that are the most available
and the most commonly used in product design. Because these same materials are representative of a broad spectrum of materials, the design engineer can use
his or her knowledge about them to communicate with materials engineers about other, less common materials.
In addition to the important properties of the 25 most used materials, this appendix also contains a list of the specific materials used in many common
items. During material selection it is vital to know what materials have been used for similar applications in the past; this list provides a source of such information.
This appendix concludes with an extensive bibliography; the publications listed there are a source for information beyond the basic data presented here.
379
380
APPENDIX
A Properties of 25 Materials Most Commonly Used in Mechanical Design
A.2 PROPERTIES OF THE MOST
COMMONLY USED MATERIALS
The following 25 materials are those most commonly used in the design of me- chanical products; in themselves they represent the broad range of other materials.
Steel and irons 1. 1020
2. 1040 3. 4140
4. 4340 5. S30400
6. S316 7. 01 tool steel
8. Gray cast iron
Aluminum and copper alloys 9. 2024
10. 3003 or 5005 11. 6061
12. 7075 13. C268
Other metals 14. Titanium 6-4
15. Magnesium AZ63A Plastics
16. ABS 17. Polycarbonate
18. Nylon 66 19. Polypropylene
20. Polystyrene Ceramics
21. Alumina 22. Graphite
Composite materials 23. Douglas fir
24. Fiberglass 25. Graphiteepoxy
The properties of these 25 materials, given in Figs. A.1–A.12, are the proper- ties most commonly needed for design purposes.
1
Other properties can be found in the references at the end of this appendix. The properties are given as ranges,
since they will depend on specific heat treatment metals and additives plastics.
1
An excellent book with more properties presented in this manner and a computer program to support material selection is M. F. Ashby, Materials Selection in Mechanical Design, 3rd edition, Butterworth
Heinemann, 2005.