May 24, 2012
A Penton Media Publication
Tune in to EngineeringTV.com
SMOOTH, TOUGH
COATINGS WITH
DIAMONDLIKE CARBON,
page 50
THE PHYSICS BEHIND
KEYSTROKES,
page 54
EMBEDDED ELECTRONICS
GO ON A POWER DIET,
page 58
.6
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RS# 102
VOLUME 84
ISSUE 8
MAY 24, 2012
CAD/CAM
•FEA helped determine the best keyboard layout
Anyone who’s ever typed on a mobile-device keypad has
probably aimed for one letter but hit a different one on
a nearby key. The result? Poor spelling, mangled messaging, or an e-mail that never should have been sent.
As electronic devices become increasingly compact,
“fat-finger syndrome,” as it is known in the industry, is
becoming a bigger problem.
Pad computers and smart phones might have flat
touchscreens that work off of pressure sensors, but keypads and keyboards that rely on the touch of a finger on a
spring-loaded key are still widely used in many electronic
devices such as desktop computers, laptops, some cell
phones, remote controls, and appliances.
•Better keyboards will make devices easier to
use
The physics behind keystrokes
Authored by:
Soo Hyun Park
Application Engineer
Manufacturing Core Technology Team
Samsung Co. Ltd.
Suwon, Korea
Edited by Leslie Gordon
[email protected], Twitter @
LeslieGordon
Key points:
• Small keyboards make typing difficult
Resources:
3DS Simulia, www.3ds.com/simulia
Samsung Co. Ltd., www.samsung.com/sec
The Global Production Technology Center of Samsung Co. Ltd., in Suwon, Korea, decided to tackle the
problem of tinier keys and denser key layouts to make
products that are both smaller and easier to use. Engineers
there delved deeper into the fat-finger phenomenon by
A prototype of a mobile
personal computer (now
discontinued) was used
in the Samsung keypad
optimization study.
FEATURES
examining the physics behind keystrokes, finger pressure,
and strike angle to determine what can go wrong and how
to correct it. The company thinks keyboards will remain
widely used for the foreseeable future, so it is important
to study the ergonomics of human-device interaction. According to Samsung, using Abaqus finite-element analysis (FEA) for realistic simulations helped engineers cut
mistyping errors with a prototype model of a QWERTY
keypad. Systematically modifying the relevant design parameters revealed keypad configurations which led to the
least number of typing errors.
To tackle fat-finger physics, engineers realized they
needed two different FE models to realistically simulate
the problem — one of a human fingertip and the other of
a device key.
Of course, nature has already determined the human-finger configuration; Samsung needed an
FEA model of it. This meant defining the separate material properties of skin, subcutaneous tissue, bone, and nail to model
the overall biodynamic response of the finger. Because
most small-device QWERTY keypad users type with both
thumbs, the engineers started from the thumb-bone structure of a 178-cm-tall male combined with exterior skin
surface data from a 3D laser scan.
Modeling the fingertip
Basing their finger-parts definitions on previous studies of human tissues, engineers queried the material database in Abaqus for the properties and element types they
needed to build the FEA model. Nail and bone were modeled as linearly elastic and the skin (epidermis and dermis)
was assumed to be hyperelastic and linearly viscoelastic.
The finger’s deeper subcutaneous tissue was represented
by a biphasic material composed of a fluid phase and a
hyperelastic solid phase (essentially a spongelike porous material representing muscle, fully saturated
with fluid to represent plasma).
Next, the team created a virtual keypad to
simulate the interaction of fingertip and key.
Model of a
fingertip
The FEA model defined the separate
material properties of skin,
subcutaneous tissue, bone, and
nail to model the overall
biodynamic response
of the finger.
Bone
Subcutaneous
tissue
Skin:
epidermis
and dermis
Nail
Thumb
tip and
dome
gets a classy
40 Indy
new chassis
Keycap
Spring dome
Substrate
Drivers will squeeze themselves
into a new chassis for this year’s
“greatest spectacle in racing.”
Realistic simulation helps design
better mobile-device keypads.
54
MACHINE DESIGN.com
MAY 24, 2012
MAY 24, 2012
54
coating
50 Carbon
toughens up parts
Diamondlike carbon can improve
the surface characteristics of
parts and pipes.
for “fat-finger
54 FEA
syndrome”
Realistic simulation helps design
better mobile-device keypads.
smarts,
58 More
less energy
ELECTRICAL/ELECTRONIC TECHNOLOGY GUIDE
More and more products depend on electronic smarts
embedded inside. The growth of embedded systems
has been spurred by computation power that lets engineers work at the module level, rather than design systems from scratch. Early embedded systems had limited
memory, CPU power, and I/O. Operating systems did
little more than boot-load a program that performed one
specific, noncomplicated task. The basic rule of thumb
became, “If it needs to do something else, add another
processor to handle it.”
If size and power were no object, than that was indeed
the path to take. Today, however, the reality of batterypowered operation and energy efficiency has intervened.
Battery life comes at a premium in embedded-system
applications found in consumer electronics, home appliances, aviation, automotive, medical electronics, and industrial automation and controls, to name just a few. Many
times over it was a case of those who knew the product being charged with adding the embedded control, of which
they knew very little.
Designers of these systems need a host of skill-sets related to computer hardware, embedded software, and electronics, as well as a background in the area of application.
To let these individuals focus on the application details
and not the electronics, embedded-system makers have
crafted more-powerful systems with features that also simplified the design process. Recent devices demonstrate the
power and sophistication found today in the embedded
world.
The power of sight
The say a picture is worth a thousand words. But it takes
millions of bits to make a picture. Processing that many
bits of data takes time, so practical vision systems need a
lot of processing power. It was quite common to find early
The combination of morepowerful embedded processors
and application modules for
specific tasks almost creates a
black-box drop-in approach to
system design.
The Abaqus
FEA model
shows the
side view
of a human
thumb tip
(top) and a
CAD model
of finger
contacting
device keys
(bottom).
vision systems housed in enclosures that dwarfed a refrigerator. Today, thanks to embedded electronics, it’s quite
possible to obtain a powerful vision system that fits in your
hand. Processors able to handle the torrent of data in these
situations include the Blackfin line from Analog Devices,
Norwood, Mass.
The Blackfin consists of both 16 and 32-bit designs that
target the demands and power constraints of embedded
audio, video, and communications applications. It uses
what’s called Micro Signal Architecture (MSA) jointly
developed with Intel Corp., Santa Clara, Calif., to better
handle data streams. Its instruction set resembles those of
reduced instruction set computers (Risc). This, combined
with dual 16-bit multiply accumulate (MAC) signal processing registers, lets Blackfin processors perform equally
well in both signal-processing and control-processing applications, eliminating the need to specify separate processors for each task.
The four latest additions to this line add dual-core capabilities at clock speeds up to 1 GHz. The ADSP-BF606
and ADSP-BF607 target general-purpose digital signal-processing (DSP) ap
as wireless communications, i
cess control, and electric powe
toring/protection. The ADSPADSP-BF609 include a high-pe
video analytics accelerator c
Pipelined Vision Processor (PV
set of configurable processing
that accommodate up to five c
rent image algorithms for high
analytics. These processors, a
with the PVP, are touted for
plications such as automoti
advanced-driver-assistance sy
Powerful embedded
processors help make more
applications energy efficient.
58
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MAY
A 24, 2012
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ON THE COVER
DEPARTMENTS
The Honda Indy car
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8 EDITORIAL
A generation of pessimists
10 EDITORIAL STAFF
12 LETTERS
16 SCANNING FOR IDEAS
Actuator provides high precision for small moves
FRAM-based RFID with built-in I/Os
20 REPORTER’S NOTEBOOK
30 LOOKING BACK
36 COMMENTARY
Yellow light for green plastics — Kenneth Korane
39 INDUSTRIAL DESIGN
Design helps combat the spread of flu
62 ORR ON ENGINEERING
Engineering your internal state
64 SOFTWARE PRODUCT S
66 PRODUCT SPOTLIGHT
Fasteners & adhesives
68
74
76
77
78
78
PRODUCTS
DATA FILES
AD INDEX
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BACKTALK
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Split cylinders increase engine efficiency
EDITOR’S WEB PICKS
Lee Teschler of MACHINE DESIGN talks with an expert from the Scuderi Group about their
split-cycle engine. It divides the four strokes of the combustion cycle between two
cylinders: one intake and compression cylinder and one power and exhaust cylinder,
connected by a gas-crossover passage. It lets engine designers optimize both strokes
for maximum power and efficiency, something that cannot be done in a conventional
internal-combustion engine. Learn more at www.engineeringtv.com/video/
Split-Cycle-Four-Stroke-Engine;Only-Engineering-TV-Videos.
6
Editor’s Web picks
Dynamic catalog
Labeling forum
Digi-Key’s new Dynamic Catalog
lets users browse more than 2 million
electronic components in categories
such as electromechanical, ICs/
semiconductors, interconnects, and
optoelectronics. Content includes
product features, specs, white
papers, and pricing information. For
information, visit www.digikey.com/
catalog.
Most labeling problems crop up
because the liner, adhesive, facestock,
printing method, and topcoat don’t
fit the application. Fabrico’s online
forum lets engineers discuss labelprinting problems and challenges,
read comments from other engineers,
and submit questions to technical
experts. Other forum topics include
High-purity piping
using structural adhesives to replace
mechanical fasteners, and bonding low- The Health-care unit of Saint-Gobain
Performance Plastics has an
surface-energy plastics. Learn more at
interactive online catalog with detailed
www.fabricoforum.com.
descriptions of more than 2,000 highSurface-treatment guide
purity piping products and components
Henkel’s 44-page Surface Treatment
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Selector Guide helps engineers
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choose products for industrial surface
detailed specs, material properties,
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adhesion, and environmental safety.
catalog at http://catalog.biopharm.saintDetailed descriptions and selector
gobain.com.
guides cover surface-treatment
Touch-technology site
products such as alkaline and acid
Mouser Electronics has a new touchcleaners, rust preventatives, irontechnology application training site at
phosphate conversion coatings, light
www.mouser.com/touch_technology.
metal posttreatments, and paint
It gives engineers information on
strippers. Download a copy or access
an interactive version at www.henkelna. products that replace traditional
switches, including touchscreens,
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MAY 24, 2012
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Product pages cover machine and
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3D motor models
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© Allied Electronics, Inc 2012. ‘Allied Electronics’ and the Allied Electronics logo are trademarks of Allied Electronics, Inc.
An Electrocomponents Company.
EDITORIAL
A generation of
pessimists
John Horgan has done it innumerable times. The noted science journalist
teaches college classes at Stevens Institute of Technology ranging from
the history of science and technology to science writing and the great
works of western civilization. At some point during his lectures, he covers
John F. Kennedy’s inauguration speech, in which Kennedy asked his
fellow Americans to join him in a quest to end poverty, disease, tyranny,
and war. Horgan then polls students about whether these four goals are
attainable or are merely utopian fantasies.
He says he always gets the same answer: College kids generally think
these goals are pipe dreams. “All my students are extraordinarily pessimistic,” he says.
Horgan first tried this exercise in 2005 and has repeated it periodically
ever since. The responses he receives are the same regardless of whether
the kids in the classroom are freshman humanities students or upperclass science writers.
It is fair to ask how we have come to the point where kids who are
college material seem to be universally downbeat about prospects for
improving the human condition. Insights into this state of affairs may
come from the French philosopher Pascal Bruckner, who blames media
coverage of apocalyptic environmentalism and the spread of apocalyptic
literature for promoting a fear of the future and a dismal view of humankind’s chances. “The fear becomes a self-fulfilling prophecy, with
the press reporting, as though it were a surprise, that young people are
haunted by the very concerns about global warming that the media continually broadcast. As in an echo chamber, opinion polls reflect the views
promulgated by the media,” he says.
Bruckner doesn’t highlight this phenomenon to denigrate globalwarming science. He merely points out that radical environmentalism is
just the latest movement to make modern society, and the abundance it
provides, a scapegoat for the world’s woes. Bruckner says all such movements have a single message: Man has committed the sin of pride; he must
atone! But the purveyors of this message have an axe to grind and it isn’t
one that promotes optimistic thinking. “These are not great souls who
alert us to troubles but tiny minds who wish us suffering if we refuse to
listen to them. Catastrophe is not their fear but their joy. It is a short distance from lucidity to bitterness, from prediction to anathema,” he says.
It is not a great leap to think that gloom about global warming has
colored the thinking of young people about the general prospects for
improving humankind. That brings us back to John Horgan and his college classes full of pessimists. “I feel it is my responsibility to get them to
be a little more cheerful in a constructive way,” Horgan says. “I try to get
them to believe that they can make the world a better place. Not that they
can necessarily get rid of poverty, war, or disease, but that they can make
progress toward those goals.”
For himself, Horgan says he is not pessimistic but realistic about scientific progress, and optimistic about large social goals, simply because, “we
have already come so far.” That is certainly a viewpoint that young people
need to hear.
— Leland Teschler, Editor
RS# 106
MAY 24, 2012
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QVKZMI[ML[XMML
EDITORIAL STAFF
QVKZMI[MLTWIL
EDITOR
Leland E. Teschler
[email protected]
MANAGING EDITOR
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The NEW 3200 iDrive and 2200 iDrive —
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iDrive
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www.Dorner.com
Kenneth J. Korane
[email protected]
SENIOR EDITORS
Leslie Gordon
[email protected]
Stephen J. Mraz
[email protected]
ASSOCIATE EDITOR
Robert J. Repas, Jr.
[email protected]
RS# 108
INDUSTRY COVERAGE:
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MACHINE DESIGN.com
RS# 109
MAY 24, 2012
AUTOMOTIVE, PACKAGING,
MEDICAL
Stephen J. Mraz
CAD/CAM, MANUFACTURING
Leslie Gordon
ELECTRICAL, ELECTRONICS
Robert J. Repas, Jr.
FLUID POWER, MECHANICAL
Kenneth J. Korane
EDITORIAL PRODUCTION
Denise Greco
Editorial Production Manager
Randall L. Rubenking
Art Director
1300 E. 9th St. Cleveland, OH 44114-1503
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RS# 110
LETTERS
GFCI chatter
L a n ny B e r k e’s c o l u m n o n
ground-fault circuit interrupters (“GFCIs — What
They Are and Are Not,” March 8)
brought up a question I’ve had
that no one has been able to
answer.
GFCIs work by measuring the
amount of current going out one
wire and checking that it all comes
back through the other wire. So,
if a person were to become part
of that circuit and some of the
current goes to ground, the GFCI
would trip because all of the current did not return to the GFCI.
That being said, GFCIs only work if
there is a path to ground.
GFCIs are required in bathrooms and kitchens but there is
no ground path in a bathtub or
sink. The drain pipes today are
PVC and with the increasing use
of CPVC and pex tubing for water lines, there is no longer a path
to ground. This being the case,
would a GFCI trip?
People are under a false assumption that if they were to drop
a radio or hair dryer in the tub or
sink, they would be safe and in my
opinion they are not.
Any thoughts?
Don Heim
This topic seems to arise repeatedly
in online forums. Though a lot of residential plumbing is PVC, I believe GFCIs are there on the chance Murphy’s
Law happens to provide a ground
path. When there is a ground path
through the human, the GFCI trips.
If there’s no ground path, there’s no
electrocution, and no GFCI tripping.
— Leland Teschler
GFCIs and policies concerning
them can have some interesting
idiosyncrasies. For example, GFCIs are not required in operating
rooms in the U. S. but are in some
other countries. This led to an interesting situation.
For example, a few years ago,
we got a complaint from a hospital in Hong Kong. It seems the
12
MACHINE DESIGN.com
Readers debate GFCIs and
call out manufacturers
One reader has a question about GFCIs and the increasingly common practice of using nonconductive pipes in bathrooms. A couple of other readers
blame manufacturers for not taking the time to
train employees. And another reader says the
imminent death of the lead-acid battery is
greatly exaggerated.
GFCI would open every time they
tried to turn on equipment used
during eye surgery made by my
employer. After a lot of skullscratching, we concluded the
power-factor correction circuit
on the equipment’s power supply was causing a burst of 30-kHz
switching when the device was
first turned on. This, in turn, was
at a frequency so high that the
EMI control circuitry shunted a
few milliamps of current into the
ground lead for the first hundred
milliseconds or so.
One particular brand of GFCI
used in that hospital apparently
lacked the HF filtering on its trip
circuit (which would ignore 30kHz “noise” as it is not a fibrillation
risk) and activated the start-up
current.
The short-term fix was to add
NTC inrush limiters to the power
supply. The long-term fix was
to find a vendor selling power
supplies with better main input
stages, which wouldn’t need to
switch the inrush surge at 30 kHz.
Interestingly, we tested GFCIs
similar to the one in the Hong
Kong hospital, even from the
same manufacturer. We could
never get one to trip in our lab,
nor would any commercial/
residential-grade GFCIs that we
bought locally ever trip. We never
could get the GFCI manufacturer
to admit that its circuit was overly
sensitive to HF currents or that
there was a difference between
MAY 24, 2012
the ones sold in Hong Kong and
those sold in Britain.
Alan Ritter
Manufacturing workers
I’ve read several articles, blogs
and letters from readers regarding manufacturers that say they
can’t find qualified help. Perhaps
rather than wringing their hands
looking forward, they should look
backwards at the guilds of the
15th to 18th centuries.
When I couldn’t find the “ideal”
candidate while I was manufacturing manager at several companies, I hired the best I could find,
often out of school, and trained
them. This had several advantages: I didn’t have to break bad
habits they had learned at previous employers, and new hires
came with an enthusiasm often
lacking in those hired from other
employers.
Their “apprenticeship” would
last from three to six months, during which time they worked at
a reduced salary. The salary was
then gladly increased when they
successfully completed the apprenticeship. Various states also
have programs where they pay
part or all of the trainee’s salary
while they are learning.
Vernon Lowery
The kids are all right
You make some great points in
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RS# 111
LETTERS
your editorial (‘Old codgers always
gripe about “the kids,”’ March 8).
Contrary to popular belief, universities have never produced
large numbers of graduates who
could be immediately productive in the workplace. The difference between then and now is
that companies once hired recent
grads, then made sure they were
gradually exposed to increasing
responsibilities based on a demonstrated ability to handle ever-more
complex problems.
Companies don’t want to do
that any more, and they shift the
blame to the education system.
What’s worse, in their efforts to appease industry, universities waste
valuable time teaching students
to use CAD tools at the expense of
teaching them the basics, such as
free-body diagraming real-world
systems or applying thermodynamics to engineering problems.
Rajan Ramaswamy
Lead-acid batteries
aren’t dead yet
Detractors of lead-acid batteries
rarely know enough about them
to be taken seriously (“Death
k nell for lead-acid batteries,”
Feb. 9). Modern lead-acid batteries are designed with 20-year operational life, are 95% efficient,
can be inexpensive, and the main
component, lead, is completely
recyclable.
Speculation about replacing
lead-acid batteries most often
comes from proponents of a
technology that might replace
them for some applications. They
are hardly objective.
Sure, lead is heavy, and electric cars, currently a small section of the battery market, undoubtedly need more energydense batteries. But debates
about which battery is best
should deal with all the issues:
efficiency, longevity, cost, recy-
Productive in all weather
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RS# 112
clability, ease of manufacturing,
availability of materials, and total energy budget.
Lead-acid batteries are miles
ahead of the pack in many of
those issues, and they ’re also
quite difficult to beat in efficiency (in terms of energy in versus energy out), a basic parameter with renewable energy.
Geoff Harris
Correction
I saw the ar ticle we wrote for
M ACHINE D ESIGN , “How Servos and
Steppers Stack Up” in the Feb. 9
issue. The text was fine. However,
the stepper versus servo profiles
graph, which was kind of the basis of the article, has the stepper
and servo profiles swapped.
Tom Kutcher
These new generation CD® Couplings feature zero
backlash precision and high torsional stiffness.
They answer today’s demanding servo motor
applications with high reverse loads and
positioning requirements. New clamp style
hubs handle increased torque on shafts
without using keyways. Manufactured of
RoHS compliant materials.
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© 2010 ZERO-MAX
RS# 113
SCANNING FOR IDEAS
Edited by Stephen J. Mraz
Actuator provides
HIGH
PRECISION
for
small moves
15-mmdiameter motor
Slotted bushing
Collet with
radial spring
Screw-to-clamp
guide rods
Diameter
cut to
locate
guide rods
Bushing
supports
end of
screw
Area between
guide rods
slotted to provide
flexure clamp
Engineers at Haydon Kerk Motion Solutions, Waterbury, Conn. (www.
haydonkerk.com), have designed a linear actuator they call a microslide
that is based on the company’s 1500 Series 15-mm can-stack motor. The
motor can be controlled using a relatively simple pulse-and-direction
signal. The actuator’s resolution is 0.0006 in./step (15 micron/step) and it
handles loads up to 13 N (3 lb). The entire actuator measures just 0.87-in.
wide × 1-in. high, and has a maximum stroke of 2.5 in. The small size and
high accuracy make it well suited for microfluidics and positioning optics,
according to the company.
An anodized-aluminum base plate houses the leadscrew bushing and
is rigidly attached to an aluminum mounting plate for the motor. The load
carriage is made from self-lubricating polyacetal and has a clearance takeup mechanism that makes the load more rigid during moves. Stainlesssteel guide rods coated with TFE support the carriage. Five different leads
are available: 0.012, 0.016, 0.020, 0.039, and 0.079 in.
For specific applications, the microslide can be customized with various mounting options, stroke lengths, magnetic and optical sensors, and
custom wire harnesses.
RS# 401
16
MACHINE DESIGN.com
MAY 24, 2012
Motormounting
plate
counterbored
to locate
guide rods
r
formation via ou
Request free in Web site at
ice
rv
Se
er
ad
Re
c
design.com/rs
ww w.machine
For info on an interesting application using
leadscrews, scan this
code or go to: http://
machinedesign.com/
article/leadscrewassembly-redesign-makesspine-implants-easier-toinstall-0420
COMPLETE
ENGINEERING
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RS# 114
SCANNING FOR IDEAS
FRAM-based
RFID
with
built-in I/Os
Two, four, six, or eight-channels
in IP67-rated BL67 platform
Address switch and
service interface
LEDs show
status
M12 plug
connector
Cordsets
Connection
for fieldbus
and power
supply
Read/write
head
RFID data
carriers (TAG)
RFID detectors
The BL Ident system from Turck, Minneapolis (www.turck.us), for reading
RFID tags or discs, is flexible in that it
lets users add I/O modules and up to
eight channels of RFID. It conforms to
ISO 5693 13.56-MHz HF standard. The
system can be added to existing platforms and supports several different
configurations, including Profibus-DP,
DeviceNet, Modbus-TCP, Profinet, and
EtherNet/IP. Standard nonprogrammable and CoDeSys programmable
gateways can have either IP20 or IP67
ratings.
BL Ident works with a variety of differently shaped FRAM-based RFID tags
and read/write intervals can be from 5
18
MACHINE DESIGN.com
to 500 mm. And tags can be rewritten
and reused an unlimited number of
times, theoretically. Tags can survive
temperatures up to 210°C and need
no cool-down period for read or write
operations, which reduces downtime.
The system can read and write simultaneously at 0.5 msec/byte, with production speeds of up to 10 msec/byte at
distances up to 500 mm.
Configuration software can help
users choose RFID equipment by simulating an application’s parameters and
values, so that users need not make
complicated calculations or evaluate
hardware compatibility issues.
RS# 402
MAY 24, 2012
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