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26 Mechanical Engineering Design
Maintenance schedule: lubrication check every 2000 hours; change of lubrica-
tion every 8000 hours of operation; gears and bearing life >12,000 hours;
infinite shaft life; gears, bearings, and shafts replaceable
Access to check, drain, and refill lubrication without disassembly or opening of
gasketed joints.
Manufacturing cost per unit: <$300
Production: 10,000 units per year
Operating temperature range: −10 to 120 F
◦
◦
Sealed against water and dust from typical weather
Noise: <85 dB from 1 meter

PROBLEMS

1–1 Select a mechanical component from Part 3 of this book (roller bearings, springs, etc.), go to
your university’s library or the appropriate internet website, and, using the Thomas Register of
American Manufacturers (www.thomasnet.com), report on the information obtained on five
manufacturers or suppliers.
1–2 Select a mechanical component from Part 3 of this book (roller bearings, springs, etc.), go to the
Internet, and, using a search engine, report on the information obtained on five manufacturers or
suppliers.
1–3 Select an organization listed in Sec. 1–6, go to the Internet, and list what information is available
on the organization.
1–4 Go to the Internet and connect to the NSPE website (www.nspe.org/ethics). Read the history of
the Code of Ethics and briefly discuss your reading.
1–5 Go to the Internet and connect to the NSPE website (www.nspe.org/ethics). Read the complete
NSPE Code of Ethics for Engineers and briefly discuss your reading.
1–6 Go to the Internet and connect to the NSPE website (www.nspe.org/ethics). Go to Ethics Resources
and review one or more of the topics given. A sample of some of the topics may be:
(a) Education Publications
(b) Ethics Case Search
(c) Ethics Exam
(d)FAQ
(e) Milton Lunch Contest
( f ) Other Resources
(g) You Be the Judge
Briefly discuss your reading.
1–7 Estimate the relative cost of grinding a steel part to a tolerance of ±0.0005 in versus turning it to
a tolerance of ±0.003 in.
1–8 The costs to manufacture a part using methods A and B are estimated by C A = 10 + 0.8 P and
2
C B = 60 + 0.8 P − 0.005 P respectively, where the cost C is in dollars and P is the number of
parts. Estimate the breakeven point.
1–9 A cylindrical part of diameter d is loaded by an axial force P. This causes a stress of P A, where
2
A = πd /4. If the load is known with an uncertainty of ±10 percent, the diameter is known
within ±5 percent (tolerances), and the stress that causes failure (strength) is known within ±15
percent, determine the minimum design factor that will guarantee that the part will not fail.