February 9, 2012A Penton Media PublicationTune in to EngineeringTV.com ANALYZING TRADEOFFS BETWEEN SERVOS AND STEPPER MOTORS, page 42 TAMING ELECTRICAL NOISE IN MOTION SYSTEMS, page 50
Trang 1February 9, 2012
A Penton Media PublicationTune in to EngineeringTV.com
ANALYZING TRADEOFFS BETWEEN SERVOS AND STEPPER MOTORS,
page 42 TAMING ELECTRICAL NOISE
IN MOTION SYSTEMS, page 50 MORE MANUFACTURERS WANT
TO “MAKE IT IN AMERICA,”
page 64 HOW TO USE THINWALLED BUSHINGS THE RIGHT WAY, page 72
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RS# 101
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Trang 4MOTION CONTROL
One of Stober’s largest helical gears
is 295 mm in diameter and is used for less than 200 mm in diameter, are used
in planetary gearboxes.
power-transmission industry says, “Speed is cheap, torque usually more expensive than generating the torque with eliminate other mechanical components, such as bearings, down the cost of motion-control applications.
Engineers should also use the most-efficient Such gearboxes use less energy, which saves money and the environment It also
All factory equipment requires some degree of components are gearboxes They are traditionally high low-speed, high-torque power needed by machinery.
main-Still, gearboxes remain widespread and popular because, as one
of the tried and true rules of thumb
in the
Engineers should know some gearing basics before specifying gearboxes.
Stober Drives Inc., www.stober.com
For info on another planetary-gear drive unit, scan this code or go to:
http://machinedesign.com/
and-pinion-drive-saves- energy-1208
article/small-light-rack-Getting themost out of
GEARBOXES
MOTION CONTROL MOTION CONTROL
Thermograms of a stepper and an equivalent servomotor show a difference than 3 sec The servomotor maintains a relatively low 30°C temperature while the stepper motor reaches 70°C
Engineers who work in motion control often start out using a tively simple approach involving stepper motors to synthesize moves
rela-Steppers are appealing in that their controllers can be simple and pensive, at least for undemanding tasks And most steppers run open loop, needing no position or velocity feedback to hit their targets.
inex-The problem comes when the application demands appreciable torque and relatively fast speeds Stepper motors can handle a range of but the economics for the stepper approach often don’t work out.
It is useful to examine some of the key differences between stepper and servomotors as a means of understanding which applications each cycles Both motor technologies employ a rotor with permanent mag- ing a dc voltage to the stator windings in a specific pattern that results and speed control.
Two key differentiators between stepper and servo systems involve the use of a feedback device and the complexity of the amplifier elec- back device Steppers are open-loop systems with no feedback.
Speed and torque needs are often the factors that determine whether servos
or steppers are the best approach.
that can give servomotors an advantage over similar steppers
fre-A technique called microstepping can minimize speed instability by dividing each step into smaller incre-
low-amplifier that regulates current is called the torque loop
is to handle loads that vary within the design parameters
if necessary to keep the servosystem moving at its grammed velocity In contrast, a stepper system has no given speed.
pro-Stepper and servosystems also perform differently cause of variations in their motor designs Stepper motors have a large number of poles and a winding inductance ex- able from a stepper motor drops off much more quickly dc-bus voltage This behavior can be seen in graphs com- paring typical stepper and servosystems In the nearby
be-The amplifier electronics in a vosystem are typically much more complex than those of a stepper sys- ply sends full-rated current to each winding set, a servoamplifier regu- lates the current levels it delivers to
ser-a servosystem produces only the rent the application needs.
cur-Because current is proportional to torque, the control loop in the servo-
How SERVOS and
STEPPERS stack up
Access our Reader Service Web site to quickly find and request information on the products and services found
in the pages of M ACHINE D ESIGN
www.machinedesign.com/rsc
58
42
ISSUE 2FEBRUARY 9, 2012
Sometimes the extra expense of
servomotors pays dividends that
stepper motors just can’t provide
Eliminating EMI in
motion systems
A logical approach to EMI/RFI
elimination offers the best chance of
getting it right the first time
Getting the most
out of gearboxes
Here are some of the basics engineers
should know before specifying
gearboxes
Why it makes sense to
manufacture in the U S.
Manufacturing in the U.S on an uptick
for good reason
The truth about
thin-walled bushings
Thicker isn’t necessarily better Here are
some common misconceptions about
thin-walled bushings
FEBRUARY 9, 2012 MACHINE DESIGN.com
2
Trang 5www.automationdirect.com/servos or www.sureservo.com
Servo Systems
Digital Servo Drive
100W Servo Motor
with connectorized Leads
Breakout Board Kit for
CN1 Control Interface
$484.00
SVA-2040
AutomationDirect Price/Part Number
Allen-Bradley Price/Part Number
*SureServo Pro software is FREE when downloaded and is also available for $9 on a CD
Agency
Approvals
for Motors:
Agency Approvals for Systems:
Agency Approvals
9 (&'212 ,# 0# systems from
100 W to 3 kW 9 1$5(2'
DirectLOGIC
PLCs or any other host control 9 0(4$1%$ 230$ on-board indexer and adaptive tuning modes 9 0$$1$23 software
9 3(*2(,+-2(-,"-,20-**$05(2'.0$1$2.-1(2(-,
velocity or torque select presets with switch inputs
and/or the multi-drop Modbus serial interface
9 -1(2(-,"-++ ,#15(2'8.3*1$#(0$"2(-,:-0
8"-3,23.#-5,:%-0+ 2
9 ,"-#$0%-**-5$0
9
For configuration, tuning and diagnostics, use the drive’s
integrated keypad/display or take advantage of the
free SureServo Pro™ PC-based software.
www.automationdirect.com
Go online or call to get complete information, request your free catalog, or place an order.
The SureServo family of brushless servo systems
from AutomationDirect is fully digital and offers a rich
set of features at dynamite prices Beginners to
experienced users can take advantage of this
easy-to-use family for as little as $978*
(100W system) * All components sold separately.
RS# 103
Trang 6SCANNING FOR IDEAS
Rugged hollow-shaft encoder can be user programmed
Fingerprint-activated switch provides biometric protection
pentonreprints.com.
Editorial content is indexed in the Applied Science Technology Index, the Engineering Index, SciSearch and Research Alert Microfilm copies available from National Archive Publishing Company (NAPC), 300
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of machinery, electrical/electronic equipment, and mechanical equipment To obtain a complimentary
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Printed in U.S.A., Copyright © 2012 Penton Media, Inc All rights reserved M ACHINE D ESIGN (ISSN 0024-9114)
is published semimonthly except for a single issue
in January, February, June, July, and December by Penton Media, Inc., 9800 Metcalf Ave., Overland Park,
KS 66212
Paid subscriptions include issues 1-18 Issue No 19 (OEM Handbook and Supplier Directory) is available at additional cost Rates: U.S.: one year, $139; two years,
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POSTMASTER: Send change of address notice to Customer Service, M ACHINE D ESIGN , P.O Box 2100, Skokie,
IL 60076-7800.
A 295-mm helical gear and
a 20-mm version, both from
Stober Drives Inc
4
Trang 7When the humidity is low, static electricity problems will happen.
EXAIR manufactures a complete line
of static eliminators to remedy common
static problems Many use our engineered airÀ ow
products to minimize air use and noise while delivering maximum
results by moving more static eliminating ions to the product surface
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@exair RS# 104
Trang 8Many manufacturers don’t realize
that energy accounts for 75% of
the cost of buying and running a
compressor Norgren’s “Guide to
Saving Energy in Compressed Air
Systems” pinpoints problems such
as leaks, misuse, overpressurization,
and flow restrictions; and explains
how to devise an action plan to
boost efficiency Download a copy
at http://apps.usa.norgren.com/
MyNorgren/pdf/NA-211Rev3.pdf.
Energy-saving
calculators
A new tool from Rockwell
Automation calculates potential
savings from powering pumps and
fans with variable-frequency drives
Users enter flow rates, operating
hours, cost per kilowatt, and other
info to see cost savings versus
conventional control methods
The online calculator is available
at www.rockwellenergycalc.com,
or engineers can download the
free mobile app to iPad, iPhone,
Blackberry, and Android systems.
O-ring calculator app
Trelleborg Sealing Solutions has
released the O-ring Calculator, a new app that determines required O-ring dimensions and products
Users enter bore or rod/shaft diameter and get O-ring and housing dimensions according
to ISO 3601 It also searches for nominal sizes, calculates recommended tolerances, and determines materials compatible with the specified media Get the free app from iTunes or the Apple
App Store Learn more at www.tss.
trelleborg.com
Hose product catalog
A new catalog from Parker
Hannifin has product and
installation information on hydraulic hoses, fittings, equipment, and accessories It includes specs, dimensional data, chemical compatibility charts, and fitting identification data QR codes link users to additional content such as training videos Learn more
at www.parkerhose.com
Mercedes E-Cell Plus
Lee Teschler talks with an engineer from Daimler
about the powertrain, NVH, and safety in the Mercedes B-Class E-Cell Plus It has pure-electric range of 70 miles, and a combustion-engine Range
Extender permits journeys of up to
500 miles View the episode at www.
B-Class-E-CELL-PLUS-El;2012-NAIAS.
engineeringtv.com/video/Mercedes-Free Webcast: February 23, 2:00 p.m EST
Today’s additive manufacturing: Injection
molding, living hinges, overmolding, and more
Objet will discuss advances in rapid prototyping, and how it lets
engineers quickly transform CAD designs into functional prototypes
that are virtually identical to the end products — including fi nished
assemblies with moving joints and parts Models are suitable for design
reviews, focus groups, and any situation that demands precise look, feel,
and function Get more details and register at http://machinedesign.com.
Free Webinars
on Pneumatics and PLCs
Take 30 to 45 min and watch free Webinars on industrial controls topics See equipment in action, and take advantage of the question and answer period at the end of each session
PNEUMATICS
This 40-min session covers the NITRA pneumatic products AutomationDirect offers The line now includes stainless-steel cylinders, filters, regulators, lubricators, solenoid valves, position switches, tubing, and fittings See working demos and customer examples
February 22, 2012, 2:00 p.m EST
CLICK PLC OVERVIEW
In this 30-min show, we cover all aspects of the powerful Click micro brick PLC, including hardware features, specifications, expandability, and installation See
a demo of the free programming software, and learn where you can download the package
March 14, 2012, 2:00 p.m EST
Visit www.automationtalk.com to
check the schedule and register for upcoming presentations Recordings of past Webinars are also available to view at your convenience
FEBRUARY 9, 2012 MACHINE DESIGN.com
6
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RS# 106
Trang 10Employment on the American factory floor is growing, up by 334,000 jobs over the past two years Journalists have taken note of the trend The tenor of
the recent headlines on the subject echo that in the New York Times, which
claimed that, “U S Manufacturing is a Bright Spot for the Economy.”
But growth in jobs is a case of good news/bad news The good news is that reports show the economy is now producing the same amount of goods and services it did in 2007 The bad news: It is doing so with 6.3 million fewer workers, despite an unemployment rate that is falling The fact is that indus-tries that include construction, transportation, warehousing, waste manage-ment, and even manufacturing, were still shedding workers at least through 2010
Growing businesses are the ones most likely to hire workers And nately, the industries that are now growing are typically not the blue-collar em-ployers that lost the most workers during the recession Figures from the U S Bureau of Economic Analysis show where the real growth in the economy has been over the last few years It is not in manufacturing Areas adding workers include agriculture, forestry, fishing and hunting, mining, retail trade, finance and insurance, health care, educational services, IT, and government
unfortu-Most of these are not what you would call blue-collar industries U S ployers in the blue-collar category are in the minority; the blue-collar indus-tries adding jobs over the past few years can be counted on your fingers They consist of mining and utilities, each accounting for a miniscule 0.5% of total
em-U S employment
Government figures show that a lot of the areas of expanding ment in the past few years are those associated with paper pushing Finance and insurance have grown to account for about 4.6% of the workforce The largest-growing employment area, unfortunately, is government, accounting for 16.9% of the U S workforce in 2010
employ-But economists say any job vacancies in these growing areas are more than offset by the joblessness stemming from still-struggling construction and manufacturing industries This is distressing for unemployed blue-collar workers in that the few expanding areas of the economy, such as education and health care, typically are not fertile ground for workers with industrial skills
All in all, the recent upturn in manufacturing jobs pales in comparison with the 2.3 million decline in factory payrolls over the past two years Put another way, manufacturing employs 2 million fewer workers than it did just four years ago This though the output of U S factories is up about 3% since
2001 The well-chronicled reason is that worker output/hour has climbed over 40% since that time, thanks to automation and adoption of new technologies
It isn’t just the manufacturing industry that has become more productive Economists tell us the economy in general has become more efficient at using
labor As brick-and-mortar bookstores put out of business by Amazon.com
will attest, nearly all industries use fewer workers to generate the same amount
of goods and services
And that’s the rub Productivity gains are just one more reason we are likely
to see persistent unemployment, and why we shouldn’t expect to soon see headlines about a real boom in blue-collar jobs
— Leland Teschler, Editor
More manufacturing jobs, but no renaissance
RS# 107
FEBRUARY 9, 2012 MACHINE DESIGN.com
8
Trang 11The engineer’s choice
The round thing has to go into
the rectangular thing.
Trang 12Power Transmission Products
38 River Road, Uxbridge, MA 01569
MITRPAK right angle,
three-way, and
counter-rotating spiral bevel drives
are interchangeable with
Boston Gear, Hub City, Browning…
and we guarantee 24-hour shipment.
For complete specifications and
CAD files, log onto www.mitrpak.com ,
or call us at 800-648-7725 Learn
how MITRPAK minimizes backlash by
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* Contact us for details.
Leland E Teschler, Editor,
leland.teschler@penton.com
Kenneth J Korane, Managing Editor,
ken.korane@penton.com
SENIOR EDITORS Leslie Gordon, Stephen J Mraz AUTOMOTIVE &
NEWS FEATURES Stephen J Mraz,
stephen.mraz@penton.com
CAD/CAM Leslie Gordon,
leslie.gordon@penton.com
ELECTRICAL, ELECTRONICS Robert J Repas, Jr.,
robert.repas@penton.com
FASTENING, JOINING Jessica Shapiro,
jessica.shapiro@penton.com
FLUID POWER Kenneth J Korane,
ken.korane@penton.com
MANUFACTURING Leslie Gordon,
leslie.gordon@penton.com
Kenneth J Korane,
ken.korane@penton.com
MATERIALS Jessica Shapiro,
jessica.shapiro@penton.com
MECHANICAL Kenneth J Korane,
ken.korane@penton.com
Jessica Shapiro,
jessica.shapiro@penton.com
EDITORIAL PRODUCTION Denise Greco,
Editorial Production Manager
Randall L Rubenking, Art Director
1300 E 9th St Cleveland, OH 44114-1503 RS# 110
RS# 109
FEBRUARY 9, 2012 MACHINE DESIGN.com
10
Trang 13WHAT MOVES YOUR WORLD www.moog.com/industrial
THE MOTION CONTROL EXPERTS AT MOOG CAN HELP YOU MAKE IT HAPPEN.
Trang 14Deregulate engineering?
The recent editorial (“Why Finance
Majors Make More than Engineers,”
Oct 20) was interesting, but my
takeaway was different than yours
You make the point that
deregula-tion of the financial industry led
to higher salaries and more
inno-vation in that field Your proposed
solution is for government to
in-crease regulation on the financial
industry, thus depressing salaries
there to bring them more in line
with engineering That’s quite a
pessimistic approach
The correct answer is to
deregu-late engineering/manufacturing
industries so as to encourage
inno-vation and let salaries rise there as
well Let the free market determine
the value of engineers
The problem with your
analy-sis is an incorrect assumption that
deregulation was the cause In
fact, the real culprit was political
interference in the lending
pro-cess in the name of increasing
home ownership Congressional
pressure, combined with
assur-ances that the federal
govern-ment would back these loans,
led financial institutions to make
risky loans This, in turn, skewed
demand in the real-estate
mar-ket, sparking the housing boom
It was only a matter of time before
individuals began to default on
loans they could not afford
Hous-ing prices plummeted and more
people defaulted as they suddenly
found themselves underwater
The whole house of cards began
to tumble down as the financial
in-dustry looked to Washington to make
good on their earlier promises
If you are looking to
govern-ment intervention to fix a problem,
you had better check first to be
cer-tain that it wasn’t the cause of the
problem in the first place
Allen Heindel
Basically, I say there is never any
free lunch If someone goes into
engineering, he’s providing a real
ser vice of value, and that can
never be reduced The free-lunch
seekers, i.e., the financial people,
often end up getting their free lunches in prison Personally, I would send these white-collar criminals to the same prisons populated with axe murderers, not some Club Fed facility
Jane Alstott
A very informative editorial on nance majors Everything makes sense, except for the last phrase
fi-If deregulation triggers nuity, productivity, and higher rewards, why would you suggest more regulation on the financial industry?
inge-There is a better way: late other industries Yes, they will
deregu-go up and down, But left lated, they will self-stabilize on a much higher level than “regulated”
unregu-ones Regulating everything only makes funnel money and power to our “Legal Industry”
Ilya Feygin
The point is that salaries in the nancial industry dropped relative to those in other industries during the 1930s and 1940s because, accord- ing to the two economists doing the study, the financial industry was increasingly regulated during that time period — Leland Teschler
fi-Do no harm
I appreciated your article on unsafe guards (“Beware of Unsafe Machine Guarding,” Sept 28) I once was forced to add a safety device to a machine that used an air cylinder to bring a guard up when the operator activated palm buttons Although the guard was raised with a low-
pressure cylinder, the operator could get whacked in the face if he or she leaned too far forward and was not paying attention I’ve also seen ma-chines using the same method to bring a guard down like a guillotine.People often design safety methods like these with the idea that they are at least making an at-tempt to keep workers safe with-out realizing the device they have installed is actually what will most likely hurt the operator
In that vein, I’ve seen machines powered by pneumatic cylinders that have a long stroke When that stroke was interrupted by a light curtain or e-stop in the middle of its travel and then reenergized, it would slam into position because the pressurized air
on the opposing side of the cylinder had drained off during the stop con-dition Adding flow controls didn’t help because there was enough empty volume in the opposite side of the cylinder to let it compress, which also let the moving components slam into position I’m not by any means a pneumatic expert So, with that be-ing said, what is the best solution to prevent this?
Rich Whitford
One of the basic concepts when ing a guard is to make sure that by adding the guard you are not adding another hazard Therefore, when- ever a machine is altered or modi- fied, perform a preliminary hazard analysis to ensure all hazards of the current machine are addressed — Lanny Berke
What are
the
RULES?
FEBRUARY 9, 2012 MACHINE DESIGN.com
12
Trang 15©2011 National Instruments All rights reserved LabVIEW, National Instruments, NI, and ni.com are trademarks of National Instruments
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RS# 112
Trang 16RPS tackles your toughest motion applications
The innovative, new Precision Roller Pinion System (RPS) from Nexen handles your most demanding linear motion control applications Simply put, no other motion system offers the combination of speed, positional accuracy, stroke length, load capacity and zero backlash performance Not to mention it’s also extremely quiet, 99% effi cient, and so refi ned it can run without lubrication Replace inferior rack and pinion, ball screw and belt drive technologies with higher performance and lower maintenance solution
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occupations have not kept pace with those of other college grad-uates, and in some occupations have actually decreased.”
In a free market, a shortfall of STEM workers would have raised compensation, but instead, wages have lagged or stagnated This leads me to conclude it is a manip-ulated market, created by domestic businesses that benefit from lower cost immigrant labor
There is also a complementary
“diversity” campaign to recruit norities, who are upwardly ambi-tious, but economically naive, and may be lured by comparatively at-tractive starting salaries
mi-Robert Rung
We have written about STEM dents who take non-STEM jobs back on May 3, 2010, “Engineering Students Who Don’t Go Into Engi- neering.” Here’s a link: http://tinyurl com/2eqjrf9
stu-dream without regard to a viable livelihood (“Advice for Occupy Wall Streeters,” Nov 17) But why is it that
“ 43% of those [STEM] graduates
do not work in STEM jobs ately after graduation”? Were there
immedi-no jobs, or did they find something else more attractive?
I believe the reasons are to be found in Ruark and Graham’s re-
port, Jobs Americans Can’t Do?: The
Myth of a Skilled Labor Shortage,
which can be found on the Web
Here are two of their findings:
t5IFHMVUPGTDJFODFBOEFOHJOFFS
ing (S&E) degree holders in the
U S has caused many S&E ates to seek work in other fields
gradu-Less than one-third of S&E degree holders work in a field closely related to their degree, while 65%
are either employed in or training for a career in another field within two years of graduating
engineering, and mathematics
Job shortage or
worker shortage?
I bought into the lies about
impend-ing engineerimpend-ing shortages and went
to an engineering school in the 80s
Unfortunately, after I graduated
en-gineering salaries were consistently
decimated by offshoring both
manu-facturing and design work, and by
importing cheap engineers (H-1B and
L1) Now, 25 years later I am sending
my daughter to an ivy-league school
(which is costing me a fortune) to
study engineering, but with explicit
instructions that she is not to become
an engineer Post-graduate business,
law, or medicine will do nicely
Engi-neering is her fallback I am not the
only parent doing this Who knows; if
this keeps up, maybe someday there
really will be a shortage of engineers
But I doubt it
Ray White
I agree with your disdain for
grad-uates who have pursued their
RS# 113
Trang 18SCANNING FOR IDEAS
Edited by Stephen J Mraz
Rugged hollow-shaft encoder
can be user programmed
The HS35 incremental hollow-shaft encoder from Baumer Ltd., Southington, Conn
(www.baumer.com/hs35), combines heavy-duty design with a precise optical scanner
to provide reliable, closed-loop control with accuracies of 60 arc-sec
TTL, HTL, and OC (open-collector) outputs Direct read resolution can be up to 56,000 ppr, but internal interpolation can boost that to 80,000 ppr And signal quality is good, even at low speeds The HS35S sine-wave encoder provides good signal quality at all speeds and prevents drive overheating while saving energy
The encoders operate in temperatures from –40 to 212°F, and are available with shaft diameters from 0.5
to 1 in
RS# 401
The heavy-duty
castings and sturdy
walls add durability
and stiffness The
large diameter
between ABEC 5
bearings, together
with a precise
long-term exposure in harsh environments And
reinforced shaft inserts electrically isolate against
shaft currents of up to 2.5 kV The inserts also let the
encoders be mounted on smaller shafts
There are three versions of the encoder HS35P is
a programmable square-wave encoder Resolutions
range from 1 to 8,192 in increments of 1 Programming
outputs include HTL and TTL Users can program
pulse per revolution, index pulse length and position,
rotation direction, and output voltages Users can also
choose independent A and B counts
HS35F is an industrial square-wave encoder with
steel spacer ring,
lets the encoder
handle relatively high
mechanical loads Dual
seals protect against
contaminants and
leaks A powder coating
prevents the housing
from corroding, despite
Seals provide IP67 rating, protecting encoder from wash downs and contamination.
Durable housing
Flexible aluminum shaft adapters
Shaft isolated against shaft currents
ABEC 5 bearings resist runout and wobble
Precision glass disc can withstand
200-g shocks.
Powder coating protects housing against corrosion.
FEBRUARY 9, 2012 MACHINE DESIGN.com
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Trang 19SIMPLE Starts here.
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Trang 20shock and
vibration-resistant housing that
meets EMC, IP65, and
NEMA-123 protection
standards The device
stores and identifies
up to 200 fingerprints,
including prints from
different fingers of the
same person The unit
records fingerprints as well It takes less than a second for a
person to be approved or denied access The false acceptance
rate is less than 0.1%
The switch installs in a standard 22-mm cutout and is
secured using a single nut Electrical connections to the power
supply and control output (a relay or PLC) are made using a
2-meter cable or an M12 connector There are two versions
of the switch One provides two output states or responses,
while the other, a momentary switch, supplies pulse control It
operates on 23 Vdc, and in temperatures from –5 to 50°C
The biometric switch can mount horizontally or vertically
An optional hinged cover protects the face of the sensing
screen, and a stainless-steel guard is also available to prevent
vandalism and weather damage if mounted outdoors
Error light
Output status light
FEBRUARY 9, 2012 MACHINE DESIGN.com
18
Trang 21YOU’LL CALL IT the most technologically advanced
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RS# 116
Trang 22REPORTER’S NOTEBOOK
The Dock + Go, a concept car from Rinspeed in
Switzerland, would give owners of electric cars
a variety of options in using their vehicles The
concept car is based on an electric “for two”
from Smart Car but could be made to work
with other small electric vehicles as well The
concept centers on using various trailers that
dock with the car when needed These trailers
could provide extra space for carrying cargo,
making the “for two” a mini pickup truck Or
they could provide an extra seat or two, tool storage
for a craftsman, a camping setup, heated or
refriger-ated space for delivering pizza or ice cream, or storage
for skis and golf clubs Trailers could also house a small
combustion engine, batteries, or a fuel cell, giving the
original electric car an extended range
Rinspeed will release more details when the car is
shown to the public at a the upcoming Geneva Auto
Show MD
FEBRUARY 9, 2012 MACHINE DESIGN.com
World’s smallest electric vehicle
could be a powered unicycle
The Solowheel, an electric unicycle, can carry a rider at up to 10 mph, for
up to 20 miles on a single charge of the battery The 26-lb device handles
riders weighing up to 250 lb, letting them stand on a pair of floorboards
that jut out from the wheel covering There is no seat But riders can
squeeze against a central pad Starting and stopping takes place by
lean-ing forward or back, respectively, much like the two-wheeled Segway
The vehicle is powered by a 1-kW motor supplied with electricity from
Resources:
Solowheel, http://
solowheel.com
Trang 23The RE6O from Baja Auto in India,
could set a new benchmark for small, inexpensive cars But the manufacturer, better known for motorcycles and motorized three-wheeled rickshaws, doesn’t even claim the RE60 is a car
They call it a motorized four-wheeler
Baja plans to sell the RE60 as for-hire vehicles, similar to the three-wheeled rickshaws common in India and Asian countries The $2,200 “car” is powered
by a one-cylinder 200-cc engine and would have a top speed of
43 mph Fuel economy, the RE60’s strong suit, is 82 mpg
When several rickshaw drivers
in New Delhi were asked if they would make the switch, they said the doors and hardtop would be a plus in the cold winters, but would make rides too hot in the scorch-ing New Delhi summers MD
a lithium-ion battery Like other electric vehicles, the Solowheel uses regenerative braking, which recharges the battery when the driver slows it down or the unicycle is traveling downhill The bat-tery can be totally recharged in 2 hr and is good for about 1,000 charging cycles
The vehicle is said to be safe on surfaces such as streets and walks, as well as on rough pavement But riders are warned to avoid slippery, wet surfaces and steep slopes
side-Solowheel is sold by Inventist LLC, Camas, Wash., for about
$1,800 and was invented by Shane Chen, the man who also came
up with the AquaSkipper, a human-powered hydrofoil MD
FEBRUARY 9, 2012 MACHINE DESIGN.com 21
World’s smallest car,
or is it even a car?
Resources
Baja Auto, www.
bajajauto.com
Trang 24The fine sand found in parts of Afghanistan and Iraq erodes and damages the blades of Apache, Chinook, and Blackhawk helicopters used by the military So far, the repair and replacement of blades has cost the military almost a half-billion dollars (New blades cost about $500,000/helicopter.) After evaluat-ing over 150 different protective coatings,
engineers at the Army Research Laboratory
have come up with a two-coating approach that seems to stave off sand-caused damage
The first coating, tungsten carbide-cobalt (WC-Co), is applied to the blade’s leading edge using high-velocity air-fuel powder spraying The second coating, cold-sprayed niobium, is put on the rest of the blade If testing is successful, the coating will likely be common on Army helicopters deployed to desert regions MD
A helicopter from the
Army Dustoff unit lands to
medevac an injured soldier
in Iraq (Photo by Lance Cpl
Kelly Chase)
Trang 25The Sandia researchers think the results could lead lighting engineers
to develop laser-based home and industrial lighting Laser diodes are
more expensive to make than ordinary LEDs because their substrates
must have fewer defects But substrate quality, which also affects LED
performance, has been constantly improving There are also problems
with the performance of yellow and green lasers And while red lasers
perform better, they are not as good as blue lasers, which are now good
enough to let BMW use them in its next-generation white headlights.
The performance disparity could be addressed by creating hybrid
lights — white lights that use lasers and ordinary LEDs For example,
blue and red diode lasers could be combined with yellow and green
LEDs
The advantage of laser diodes is that they can handle electrical
currents above 0.5 A and create more light efficiently as the electric
current increases LEDs, on the other hand, lose efficiency at currents
over 0.5 A MD
A researcher adjusts the setup used to compare LED and
diode-laser-based white lighting.
RS# 118 FEBRUARY 9, 2012
Your next table lamp
Combine blue, red, green, and yellow laser light and you will get white
light, but perhaps a white light you wouldn’t want illuminating your living
room It’s long been thought that the extremely narrow band of
wave-lengths generated by the four lasers would create a harsh white light
con-sumers would find unpleasant and uncomfortable
But researchers at Sandia National Laboratory wanted to see if this
was indeed true So they conducted a survey in which participants looked
at images illuminated with white light from one of five different sources:
LEDs producing warm, cool, and neutral light; a tungsten-filament
in-candescent light bulb; and four lasers tuned to produce white light
Par-ticipants reported no significant difference between the light from the
incandescent, the neutral LED, and the combination of four laser lights
Interestingly, they also put the cool and warm LEDs at the bottom of the
list for ease of viewing and realism
Trang 26Decentralized Servo Drives iX
offer unprecedented freedom
in mounting options:
The Advantages for the
OEM are in plain sight:
EtherCAT and Sercos III
Continuous Power up to 5 kVA
A chemical engineer at Stanford University has developed a
pres-sure sensor based on a pair of transparent films of single-walled bon nanotubes The nanotubes act as springs, letting the sensor accu-rately measure forces on it as it is being pulled like taffy or squeezed like a sponge
car-The nanotube layer is created by suspending hollow nanotubes in
a liquid, then spraying the liquid onto a thin layer of silicone which is then stretched The stretching aligns some of the randomly oriented clumps of nanotubes into lines in the direction of stretching When the silicone is released and snaps back to its origi-
nal shape, the nanotubes buckle and form tures resembling nanoscale springs The material, along with the lines of nanotubes, can then be repeatedly stretched in any direction without per-manently changing the shape of the silicone
So far, the Stanford researcher has built sensors that can detect pressures ranging from 20 mg to 30,000 lb She is trying to make the sensor more sensitive and develop algorithms that will let users de-termine if the sensor is being stretched or compressed This sensor technology could lead to touch-sensitive prosthetics and robots, as well as improved computer touchscreens MD
Pressure sensors that stretch like skin
RS# 119
FEBRUARY 9, 2012
Trang 2751 Parmenter Road, Hudson, MA 01749
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COATED INDUSTRIAL DEVICE
The Leader
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Three gripper modules are connected using silicon rubber, letting them bend and conform to curved surfaces.
pushing it away A team of engineers at the
Massachusetts Institute of Technology
have devised a solution: Give the robot a
way to “grab hold” of ferrous surfaces
The MIT gripper, or controllable
adhesion system, uses controllable
electromagnets, magnets that can be turned on and off using
little energy Their original gripper module contained two
parallel-bar magnets One is neodymium-iron-boron and is
relatively strong The other, weaker one is wire wrapped and
made of aluminum-nickel-cobalt (AlNiCo)
At first, the magnets are mirror images of each other, with
their north-south orientations reversed and their magnetic
fields canceling each other out But if a current pulse is sent
through the weaker magnet’s coil, its north and south poles
switch, making the overall module a strong electromagnet,
capable of anchoring a robot to a pipe or ship’s hull A second
pulse sent through the coil switches polarity back, and the
module is no longer magnetic One major advantage of
this setup is the module stays in either state with no energy
applied
Researchers changed the layout of the magnets so that a
cylindrical AlNiCo magnet is surrounded by a hollow toroid
NIB magnet The coil wraps around both magnets, but the
NIB magnet is too strong to be affected by the current pulse
A steel cup confines and focuses the magnetic field when
the module gets clamped onto a surface, This arrangement
creates a stronger magnet than the parallel bar configuration
Connecting up to three modules using a flexible silicon
rubber sheet lets the gripper modules conform to curved
surfaces For example, the three modules can surround a
pipe, And the three magnets do not interfere with each other
The team will check to see if protective plastic coatings
or biological organisms on surfaces will interfere with the
www.mit.edu
RS# 120 FEBRUARY 9, 2012
Giving underwater
robots a firm grip
Trang 28filters But the high speed of sound
in hydraulic fluid, along with the low fundamental frequencies of pumps, results in wavelengths of fluid-borne noise that are much longer than the practical size of common noise-control components
To eliminate these difficulties, the research team added a polymer lining — made of a nonhomogeneous, microvoided engineered material — to a prototype silencer Experiments showed that the silencer produced 25 dB of transmission loss from 200 to 3,000 Hz, and performed comparably to a similarly sized commercial bladder-style silencer The team has also built other noise-control devices that incorporate the lining, including a Helmholtz resonator, tuning coil, and a Quincke tube
The prototype Helmholtz resonator is reportedly two orders of magnitude smaller than an unlined resonator of the same resonant frequency
The team’s test rig permits research into the acoustic performance and transmission loss of two-port hydraulic components including silencers, accumulators, hoses, branch resonators, and valves MD
A new approach to squelching noise in
hydraulic systems applies compliant linings
to noise-control devices for fluid-power
systems
A research team from Georgia Tech, with
funding from the Engineering Research
Center for Compact and Efficient Fluid
Power (CCEFP), seeks to reduce noise and
vibration by putting engineered-compliant
materials into existing components The
materials may also reduce the size of
noise-control devices
Noise is an all too familiar problem in
the fluid-power industry Fluid-borne noise
generated by components within hydraulic
systems, most significantly pumps, can
cou-ple to structures and cause vibration and
air-borne noise Excessive noise increases
mechanical fatigue and reduces
compo-nent life, not to mention posing a health
hazard to nearby workers
Current methods for reducing
fluid-borne noise rely on pressurized, gas-filled
bladders that add compliance to
fluid-power systems Engineers also include
design features that address noise sources
such as cavitation and structural vibrations
Pressurized bladders used in
commercially available in-line silencers
and in accumulators act as low-pass
Trang 29in the lab has been around for years, we believe Virent, Gevo, and Avantium can make them on a globally commercial scale within the next few years,” says Coca-Cola’s Rick Frazier, vice president, commercial product supply The three companies will develop all the materials and make sure they meet all of Coca-Cola’s and the industry’s
recycling requirements
Virent in Madison, Wis., has patented technology that uses catalytic chemistry to turn plant-based sugars into a range of products identical to those made from petroleum, including bio-based paraxylene — a key component needed for 100% plant-based PET packaging PET made from Virent’s bio-based paraxy-lene is said to have the same quality and recyclability
as materials used today, but is made from renewable materials The company is targeting early 2015 for the opening of its first full-scale commercial plant Gevo
in Englewood, Colo., will also support the paraxylene endeavor
Avantium in Amsterdam has technology said to duce bio-based PEF bottles with good properties at a competitive price The process, called YXY, starts with plant-based feedstock which is used to make packag-ing materials such as PEF bottles “We have produced PEF bottles with promising barrier and thermal prop-erties,” says company CEO Tom van Aken MD
pro-Coca-Cola is working with
bio-technology firms Virent, Gevo,
and Avantium on beverage
bottles made from plant-based
materials The effort builds on
Coca-Cola’s first-ever recyclable
polyethylene terephthalate (PET)
bottle, which is partially made
from plants The company
has already sold more than
10 billion of its PlantBottles
in 20 countries since
intro-ducing it in 2009
PlantBottle packaging
is made of monoethylene
glycol (MEG) and purified
terephthalic acid (PTA) The
next-generation
biomate-rial bottle will replace PTA
with plant-based materials
Coke eventually wants
to convert all of its plastic
packaging into plant-based
materials “While the
technol-ogy to make biomaterials
If all goes as planned, The
Coca-Cola Co.’s PlantBottle
will be entirely made of
plant-based materials
within a few years.
Resources:
Avantium, www.yxy.com The Coca-Cola Co., www.
thecoca-colacompany.com
Gevo, www.gevo.com Virent Inc., www.virent.com
RS# 122
Coke bottles jump on the
biomaterial bandwagon
Trang 30Omax waterjet-cutting system
on their own without any direct supervision “It’s rare to turn an undergraduate engineering stu-dent loose on a conventional CNC machine,” he stresses
“The waterjet system teaches students about manufacturability,” says Nakane And fast turnaround lets them try out several options which, in turn, leads to more-com-plete designs Prior to installing the Omax machine, prototyping was long and drawn out, with a lot
of time wasted simply trying to ure out how to run the CNC equip-ment “Students basically had one
fig-or two attempts at getting their designs right,” explains Nakane.Students are exposed to the waterjet in their second year at UBC Then the technology must be incorporated into their senior proj-ects — building small robot cars that must run a tabletop course mapped out with electromagnetic tape Nakane says that just as with
Talk to most any manufacturer
and a common complaint is that
recent engineering grads don’t
have practical, hands-on
experi-ence — especially when it comes
to manufacturing
The engineering department at
the University of British
Colum-bia in Vancouver, Canada, seeks
to counter that trend by making
abrasive waterjet cutting part of
the college coursework
Waterjet cutting lets students
quickly go from CAD drawings to
finished parts But what’s perhaps
more important is that for most of
the students, it’s usually the first
time they’ve ever been exposed to
such technology — or any
manu-facturing technology, for that
mat-ter — explains Jon Nakane,
engi-neering lab director at UBC
Why a waterjet, instead of a
lathe or milling machine?
Waterjets let inexperienced
stu-dents quickly learn to make parts,
compared with more traditional
manufacturing methods such as
machining parts from raw blocks
of steel, says Nakane Waterjet
machining is simple and
straight-RS# 123 FEBRUARY 9, 2012
MACHINE DESIGN.com
28
Waterjets are mainstream
for engineering students
Trang 31
Many military robots rely on flexible, flat cables from
Cicoil Corp., Valencia, Calif
The cables’ form factor makes them lightweight and com-pact, which saves space and power The cables also carry more current than traditional cables, which reduces skew-ing effects and improves other electrical characteris-tics as well The cables are en-closed in silicone jackets that absorb shocks and protect parts from vibrations And unlike PVC, polyurethane, or Teflon jacketing, which need clamps to keep conductors from creeping out of them over time, snug silicone coverings keep the conduc-tors from working their way out Cicoil cables withstand water, humidity, temperatures from –65
to 260°C, and other rigors of turbulent flight Cable options include power con-ductors, shielded signal pairs for EMI/RF
any other engineering
pro-gram, the goal is to solve
specific problems And the
short time frames involved
mimic how products get
products, says Nakane
“The waterjet helps teach
and propagate that
mindset in our students.”
They learn how to talk to
machinists and explain
how to turn designs into
products “Hands-on time
with the waterjet is critical
to this learning,” Nakane
emphasizes
The fabrication work is
coupled with spot
weld-ing, press breaks, and
other forming methods
On average, about 250
UBC students use the
wa-terjet annually MD
RS# 200
FEBRUARY 9, 2012 MACHINE DESIGN.com 29
Electronic cables keep military robots on the battlefield
Trang 32Request a catalog at catalog@ondrives.us
Clean commuting: The New
York Power Authority is
teaming up with Ford Motor
Co to give metropolitan commuters
a clean transportation alternative
The “NYPA/Think Clean Commute”
program aims to reduce air pollution
and traffic congestion
Ford is ing the Think City electric vehicle (EV) to commuters in Westchester, Queens, Putnam, Nassau, Suffolk, and Rock-land counties for $199 monthly Par-
leas-ticipants can charge up at commuter train stations while they’re at work or install chargers at their homes.Think City EV is a two-passen-ger vehicle with a range of approx-imately 50 miles and a top speed
of 55 mph
30 YEARS AGO — 1982
Tires extruded from vinyl:
Semipneumatic tires for tions ranging from mobile toys to garden equipment are now being
applica-extruded by Hamelin Industries
Inc from Geon vinyl supplied by BFGoodrich Chemical Group.
The process, according
to Hamelin,
is unique to the indus-try; most semipneu-matic tires are made from compression-molded rubber The advantages of vinyl include extra-long wear, an assortment
of colors at little or no additional expense, and it’s nonmarking In addition, Hamelin claims the ex-trusion process also allows more flexibility in profile design at a lower tooling cost to the customer
50 YEARS AGO — 1962
Wings for Denison: The HS Denison,
a 90-ton ocean-going hydrofoil
being developed by Grumman
Aircraft Engineering Corp for the
U S Maritime Administration, was
fitted with two 5½-ton main foils A third, stern-
mounted foil will be fitted later
Developed primarily for research purposes, Denison will eventually be put into passenger service between Port Everglades, Fla., and the Bahama Islands She will carry 60 passengers Powered by an 18,000-hp gas tur-bine, the craft will have a maximum speed of 90 knots MD
FEBRUARY 9, 2012 MACHINE DESIGN.com
30
Trang 33Try Solid Edge for free!
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RS# 124
Trang 34COMPANY NEWS
AWARDS
Spirol International Corp., Danielson,
Conn., was presented with the 2010
GreenCircle Award by the Connecticut
Dept of Energy and Environmental Protection for the creation of the
Spirol Nature Conservation area Spirol
manufactures engineered components for fastening and joining, including coiled and slotted spring pins, solid pins, disc springs, alignment dowels and bushings, spacers, compression limiters, machined nuts, threaded inserts for plastics, shims, pin and
insert installation equipment, and vibratory parts feeders
Dr Manfred Wittenstein,
president of the Wittenstein
Group, Igersheim, Germany,
was named “Entrepreneur of the Year” in the “Industry” category during Germany’s prestigious 15th annual “Entrepreneur of the Year” competition Wittenstein produces alpha servodrive components, electromechanical products, and servosystems
CERTIFICATION
The X20 System from B&R
Industrial Automation Corp.,
Roswell, Ga., has been certified for maritime use by the certification institute Germanischer Lloyd (GL) The X20 System, a complete control and remote I/O system, consists of a bus module,
electronics module, and terminal block that allows many different assemblies using a single platform B&R manufactures automation equipment
APPOINTMENTS
Murata Power Solutions,
Mansfield, Mass., has made the following appointments: Bill Smith to the position of Director Product Management for board-mount power products RS# 125
FEBRUARY 9, 2012 MACHINE DESIGN.com
32
Trang 35PELICAN PRODUCTS , INC
23215 Early Avenue, Torrance, CA 90505 866.628.9890 (TOLL FREE) Q 310.326.4700 Q FAX 310.326.3311
PELICAN
TRUST YOUR TECHNOLOGY TO OURS
Mission Critical Custom Case Engineering
Harnessing our global resources, Pelican-HardiggAdvanced Case Solutions™ develops custom case solutions using a multidisciplinary process under the industry’s most experienced project management team
Driven by your product’s specifi cations, usage and environmental analysis, these custom case solutions can provide you with the highest level of Mission Critical confi dence in the fi eld – guaranteed
RS# 126
Trang 36© 2012 COMSOL COMSOL and COMSOL Multiphysics are registered trademarks of COMSOL AB Capture the Concept is a trademark of COMSOL AB
MAGNETIC BRAKING: Lorentz forces result in a braking torque
when a magnet is brought into the vicinity of a rotating copper
disk Shown are the eddy currents (arrow plot), and electric
potential fi eld on the disc and magnet.
comsol.com /showcase
With COMSOL Multiphysics ® you are empowered to build
simulations that accurately replicate the important
charac-teristics of your designs The key is the ability to include all
physical effects that exist in the real world This multiphysics
approach delivers results —tangible results that save precious
development time and spark innovation
packages that include the 3D printer and everything needed to print 3D models
For more information, contact Stratasys at info@stratasys.com;
(888) 480-3548, or www.stratasys.
com.
(medium to high power dc/dc board-mount line)
Lisa Keller, previously the Director of Engineering,
is now Director Front End Product and Program
Management Mike Schiano takes on the position
of Director Planning and Business Development
Murata design and manufactures dc/dc converters,
ac/dc power supplies, magnetics, data-acquisition
devices, and panel meters
3D PRINTING
Stratasys, Minneapolis, will
begin leasing bundled 3D-printer packages that include the new special edition uPrint 3D printers
The uPrint SE 3D Print Pack and the uPrint SE Plus 3D Print Pack are complete 3D-printing
DESIGN2PART SHOWS SCHEDULE
Design-2-Part (D2P) Shows, the est design and contract manufactur-ing trade shows in the U S., have released their 2012 show schedule D2P provides design engineers, man-ufacturing engineers and managers, and purchasers the opportunity to meet local and national job shops and contract manufacturers to source custom parts, components, services, and design
larg-The schedule is as follows: Texas D2P Show, Feb 21-22, Gaylord Texan Convention Center, Grapevine, Tex.; Northern California D2P Show, March 21-22, Santa Clara Convention Center, in California; Southeast D2P Show, March 28-29, Cobb Galleria Centre, Atlanta, Ga.; Mid-Atlantic D2P Show, April 11-12, Meadowlands Exposition Center, Secaucus, N J.; Greater Chicago D2P Show, May 1-2, Schaumburg Convention Center, Schaumburg, Ill.; Midwest D2P Show, June 13-14, Saint Charles Convention Center, St Charles, Mo.; Greater Ohio D2P Show, Sept 19-20, John S Knight Center, Akron, Ohio; Southern Califor-nia D2P Show, Oct 2-3, Long Beach Convention Center, Long Beach, Calif.; Northwest D2P Show, Oct 23-24, Metropolitan Exposition Center, Port-land, Oreg.; New England D2P Show, Oct 31 & Nov 1, Royal Plaza Trade Center, Marlborough, Mass.; South-east D2P Show, and Nov 14-15, State Fair Exposition Center, Raleigh, N C
For more information, visit www D2P.com MD
RS# 127 FEBRUARY 9, 2012 MACHINE DESIGN.com
34
Trang 37M i c r o h y d r a u l i c s
M a c r o c a p a b i l i t i e s
Lee Shuttle Valve Shown actual size Designed to isolate the normal from the emergency hydraulic sys- tem So small,
it fits right into the head
of an actuator.
So much reliability and performance, in so little space.
Creating high-performance flow control on a micro scale has been
The Lee Company’s exclusive focus for more than 50 years And
it’s been a successful mission, as evidenced by thousands of applied
Lee Microhydraulics designs – ranging from less than 0.10 in to 1.00 in
in diameter, and 0.1 to 68 grams, for operating pressures to 8,000 psi
But small size and light weight are just the beginning.There’s
also absolute reliability built into every Lee component through
100%testing and inspection Zero defects It’s a production benchmark
that has enabled Lee to meet demanding application needs in all
sorts of industries Aerospace, medical instrumentation, automotive,
machine tools and oil drilling, to name a few
The innovative problem solvers.
We don’t just satisfy requirements We also solve problems –
whether by simple modification, or ground-zero design engineering
The Lee Company is the world’s most capable and proven source
for hydraulic-component innovation And we’ve documented this
claim in extensive detail with the Lee Technical Hydraulic Handbook
An invaluable reference, the Lee handbook contains essential data
on the entire Microhydraulics product line, which includes:
Lee Shuttle Valves Detented, spring-biased, inverse,
loose ball and zero leak shuttle valves from 50-700 Lohms.
Lee Safety Screens Best protection for critical system
elements 75 to 500 micron hole size Pressures to 7,500 psid.
Lee Pri Pressure relief valves in insert form.
50 to 400 Lohm capacity 20 to 5,400 psid cracking pressures.
Lee Directional Flow Control 40 to 20,000 Lohms
in metered direction 12 to 470 Lohms in free-flow direction.
Lee Restrictors Single and multi-orifice restrictors.
200 to 2.2 million Lohms.
Lee Plugs The best way to seal drilled holes to 32,000 psi.
No O-rings, threads or sealants required.
Lee Cheks All-metal and zero-leak check valves.
4 to 400 Lohms.
Essential reading for designers of hydraulic systems.
Send for your free copy.
The Lee Company
2 Pettipaug Rd, Westbrook CT 06498-0424 860-399-6281 Fax: 860-399-2270 1-800-LEE PLUG
www.TheLeeCo.com
Innovation in miniature.
RS# 128
Trang 38Standard and Custom Clutch, Brake
& Power Transmission Solutions
291 Boston Turnpike % Bolton, CT 06043
Kenneth J Korane
Managing Editor
Been following the cellulosic ethanol fiasco? In a nutshell, Congress passed
a law five years ago mandating that oil companies blend cellulosic fuel into gasoline That’s the biofuel made from switchgrass, corn cobs, wood chips, and other plant waste Refiners are supposed to use 500 million gallons this year, and the requirement eventually grows to 16 billion gallons in 2022.Problem is, no one was producing cellulosic fuel outside the lab when the law was passed And despite the government’s insistence and hundreds of mil-lions in subsidies and tax credits, researchers and refiners still haven’t figured out how to make it economically in commercial quantities The EPA recently admitted that less than 0.1% of required renewable fuels will come this year from cellulosic biofuels
Yet incredibly, because no cellulosic fuel is available, oil companies must purchase “credits” from the EPA, at about $1.20/gallon, for failing to buy a
product that doesn’t exist As the head of the National Petrochemical and
I say, if the government is going to senselessly mandate the impossible and
levy fines for noncompliance, let’s focus on areas that really need attention.
is called a strike, then the next one — clearly over the inside corner — is how a ball? If the military can plant a cruise missile to within a couple feet of a target a thousand miles away, certainly MLB should be forced to devise a sen-sor array to tell a ball from a strike
strip-searched, and groped? We’re already shelling out $200,000 apiece for security scanners that pose potential health hazards Let’s make the TSA invent a safe, noninvasive way to detect weapons and explosives and apply artificial intel-ligence to differentiate between someone packing heat and limping with a titanium hip — all while we’re merely walking to our gate without passing through a security gauntlet
flying car? In the 60s TV series, The Jetsons, commuting was by cars
resem-bling flying saucers with clear bubble tops Fifty years later, we’re still glued to
the ground The government should put the screws to the slackers at Boeing and GM Think of the benefits: Instead of being stuck in traffic, fast commutes
would mean less pollution, less stress, higher productivity, and more leisure time Then we could all have George Jetson’s workweek: three hours a day, three days a week
and solar farms are becoming commonplace How about legislation ing a portion of the power comes from cold fusion? Though unproven — and likely a scam — who can argue with the economic benefits from cheap and abundant energy, not to mention all the make-work jobs for researchers, sci-entists, and engineers
demand-Have a wish? Write to Congress MD
RS# 129
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Trang 39Bosch Rexroth Corporation
www.boschrexroth-us.com
Mastering challenges together — Rexroth makes it easy to implement automation.
Our many years’ experience in a wide range of industries has given us extensive application knowledge We offer this comprehensive understanding to the tasks you bring us, leading
to ingenious solutions.
Regardless of the drive technology used, we thought ahead and integrated intelligence throughout This consistency makes you more effi cient — from planning to start-up and daily operation Your benefi ts are real: Increased productivity, improved energy effi ciency and maximum machine safety You can count on Rexroth to have the appropriate drive and control solution to meet your needs exactly.
Tough application, ingenious solution
Exactly
RS# 130
Trang 40In historical terms, the death of the flint tool, cooking
by dung, and other bygone technologies occurred
rap-idly because several factors conspired to bring in better
alternatives So it is with lead-acid batteries
This huge industry faces an unspectacular future
in vehicles — their main use Granted, conventional
car and truck sales are still increasing thanks to China
and other emerging nations, to around 70 million
ve-hicles annually And there seems to be ongoing use of
lead-acid traction-battery power in electric bikes,
fork-lifts, boats, and mobility vehicles for the disabled — say
35 million vehicles yearly However, every month
an-other threat appears that constitutes a serious nail in the
coffin for an industry that has served the world well for
over 100 years Recent examples include:
when a vehicle stops, however briefly, improves fuel
efficiency and reduces emissions Thus, the use of this
technology is expected to surge in the next few years For
urban vehicles with frequent stops, however, lead-acid
batteries have difficulty coping, particularly at low
tem-peratures “Microhybrids” seeking to capture and
regen-erate braking energy compound the problem
Lithium-ion batteries are, therefore, increasingly preferred
off, particularly industrial and commercial versions
Add to that the Toyota Prius, which is expected to
ex-ceed 1 million in annual sales within a few years, along
with the huge number of new hybrid and pure electric
models becoming available Forecasts are for on-road
hybrids and EVs with modern batteries to comprise 10
to 20% of global production in 2022
seem cheap until you look at their poor performance
and painfully short life Fuel cells and lithium-ion
bat-teries are coming on for indoor electric industrial
vehi-cles as well as outdoor hybrid forklifts and earthmovers,
where lead acid is completely unacceptable
batteries today, but nearly all of them are in China Lead
acid is almost entirely shunned in other countries
be-cause of its heavy weight and poor life and performance
Everywhere, bikes are moving from mainly
battery-assisted pedaling to so-called e-bikes and scooters with a
throttle Lead acid cannot keep up with power demands
of these larger two wheelers
num-ber of Chinese cities are banning or severely restricting
electric bikes due to accidents, congestion, and improper disposal of lead-acid batteries on more than 100 million electric bikes in use China wants to leapfrog in technol-ogy and there is no leapfrogging with lead-acid batteries Concerns over pollution from smelting, manufacture, and disposal are driving the Chinese government to cut lead-acid-battery production to 42% of 2010 levels Few of the 1,930 inspected manufacturers will remain and the many unlicensed sites will be sought out and destroyed Outside China, ever tougher emission laws impact everything from tugboats to aircraft Vehicles with lead-acid batteries are increasingly inadequate in addressing those requirements
their costs will drop by at least two-thirds in the next cade, according to developers, while tiny new range ex-tenders and energy harvesters reduce the size of battery needed
capaci-tors have four times the life of rechargeable batteries, ate much faster charge-discharge, and use readily available materials Their self-discharge and energy density have been poor but are improving Some now hold a charge for
toler-a month toler-and htoler-ave the energy density of toler-a letoler-ad-toler-acid btoler-at-tery Certain electric buses run on supercapacitors alone
bat-Indeed, Elon Musk, founder of Tesla electric car company,
thinks supercapacitors are the future, not batteries.Add in other factors such as the impending use of fuel cells in fleets, battery suppliers and governments focusing their R&D on alternatives, and consumers de-manding much better vehicle performance and it’s clear lead-acid batteries will be the losers
Investors see the lead-acid battery industry as ing on an escalator going down — faster and faster – even though sales statistics have yet to reflect this Niche mar-kets will remain but clearly, lead-acid batteries are suffer-ing death by a thousand cuts and the end will come more suddenly than most expect MD
stand-Battery technology will be a key topic at IDTechEx’s upcoming
Electric Vehicle conference (www.IDTechEx.com/evUSA) March
27-29 in San Jose.
Edited by Kenneth J Korane
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