Machine design, tập 84, số 07, 2012

for wind power Innovative new designs for wind turbines promise to cure problems ranging from noisy props to poor efficiency in moderate breezes.. Canada/Mexico: one year, $79; two years

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RS# 101

No.

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Ultra Precision three-axis

a toric with a sine-wave pattern in brass Final surface is produced without postpolishing.

UPM also obtains surface finish Ra values better than 0.5 nm When using diamond tooling

on nonferrous materials, UPM produces yet more-impressively smooth finishes.

Ametek Precitech, in Keene, N. H., manufactures UPM equipment and has provided

the benchmark for this technology Precitech’s machine layout resembles that of standard position Workpiece spindle speeds hit 18,000 rpm and milling spindles rotate at 15,000 or them by a factor of 10.

The company’s machines have a solid foundation made with a sealed granite base that provides physical and thermal stability Mounted on pneumatic isolators, the base remains protected from external excitation including footfalls, road traffic, and nearby mechanical equipment.

In addition, the UPM machines have an axis stiffness as high as 875 N/μ as well as tive Control Technology (ACT), which analyzes feedback, including disturbances ACT also provides active cancellation (analogous to noise-canceling headsets) that continually

Adap-Ultraprecision machining (UPM) comes However, the technology has the poten- turers, in general, finish parts or make fine-featured patterns.

First, recall that “high precision” in ditional machining generally refers to tol- erances in the single-digit micron range

tra-In inch units, machinists talk about ing “tenths” (ten-thousandths of an inch, machining and grinding machines typi- cally get Ra values no better than 0.1 μm

hold-better by holding submicron tolerances

is one of the first to adopt a noncode approach to writing application programs, relying on operational block diagrams to program the system.

Development cycles have shortened dramatically So computer-powered applications starting with a stand- alone computer or processor.

Consequently, computer and chipmakers have added new and more-powerful functions into the silicon of a computer chip The result heralds the advent of comput- nication interface, and I/O functions targeting specific graphics, and industrial control.

One of the earliest examples of such a single-purpose design is the PC/104, a single-board computer architec- able accessory boards to fit numerous application needs.

As small as the PC/104 system is, some applications required even-smaller processors Stepping down in (SOC) combined all aspects of the single-board com- puter into a single module or integrated-circuit form.

SOMs take the individual dies of multiple devices such as a processor, memory, and I/O, and mount them onto a common substrate material The tighter integra- tion has led to smaller but more-powerful systems in the Reconfigurable processors hold the key to

A

SOFTWAREDEFINED FUTURE

for embedded controls

ing, improve performance, and future-proof the design development or even after they have deployed the em- bedded system.

FPGAs have always been used as the “glue” logic that ties various parts of the system together But as their per- formance rose while power and cost dropped, FPGAs took on the additional task of handling signal process- ing Today FPGAs perform the functions of digital filters, control loops, among many other things Most times side of the system, boosting processing speed while giv- ing more deterministic control of the application The addition of FPGAs to embedded systems has become so common that new SOC releases now con- tain both a complete microprocessor and an FPGA in a

Xilinx, San Jose The Zynq integrates a dual-core ARM

Cortex-A9 processor with a Xilinx 7 Series ble FPGA and an industry-standard AXI interface The

programma-piece of equipment for a specific purpose Examples of complete computing platforms.

Computers-on-modules (COMs) are a subset of SOMs that integrate an entire computer on a single mod- ular device While still considered as embedded systems, typical of the other embedded approaches.

The push to make systems still smaller has freed makers to form all devices onto a single die, the SOC

chip-mounted to a substrate, all devices are etched onto a gle die of silicon or other suitable material.

sin-But there is a problem with this approach Many sign teams may use the same SOC or SOM as the basis final designs that are distinctively different from those

de-or SOM with additional discrete components and grammable logic For example, field-programmable gate arrays (FPGAs) let design teams add specialized process-

pro-MAY 10, 2012

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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

for wind power

Innovative new designs for wind turbines

promise to cure problems ranging from noisy

props to poor efficiency in moderate breezes

A software-defined future

for embedded controls

The future of embedded computing includes

devices with more power, features, and

simpler programming systems

Software that examines bearing

fundamentals leads to better designs

Working with

dimensional tolerances

Understanding the nuances of tolerances

makes life easier for engineers

MACHINEDESIGN’s

ISSUE 7MAY 10, 2012

MAY 10, 2012

MACHINE DESIGN.com

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RS# 103

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proof-EDITORIAL

The wind industry needs more inventors

EDITORIAL STAFF

LETTERS

SCANNING FOR IDEAS

Magnetic brake’s microcontroller eliminates

Why aren’t more manufacturers embracing

sustainable metalworking? — Doug Watts

INVENTOR’S CORNER

Lockbox secures software dongles

MECHANICAL TECH GUIDE PRODUCTS

4

The Truth About Compressed Air!

Facts about Blowers

Energy conscious plants might think a blower to be a better choice due to its slightly lower electrical consumption compared

to a compressor In reality, a blower is an expensive capital expenditure that requires frequent downtime and costly maintenance

of fi lters, belts and bearings Here are some important facts:

Filters must be replaced every one

to three months.

Belts must be replaced every three to six months.

Typical bearing replacement is at least once

a year at a cost near $1000.

G
Blower bearings wear out quickly due

to the high speeds (17-20,000 RPM) required to generate eff ective airfl ows.

G
Poorly designed seals that allow dirt and moisture infi ltration and environments above 125°F decrease the one year bearing life.

G
Many bearings can not be replaced in the

fi eld, resulting in downtime to send the assembly back to the manufacturer Blowers take up a lot of space and often produce sound levels that exceed OSHA noise level exposure requirements Air volume and velocity are often diffi cult to control since mechanical adjustments are required.

To discuss an application, contact:

EXAIR Corporation

11510 Goldcoast Drive Cincinnati, Ohio 45249-1621 (800) 903-9247

Fax: (513) 671-3363 email: techelp@exair.com www.exair.com/45/423b.htm

Compare these Blowoffs

Th ere are a variety of ways to blow the water from the bottles shown in the photo below, but

which method is best? To decide, we ran a comparison test on the same application using

four diff erent blowoff methods: drilled pipe, fl at air nozzles, Super Air Knife (each using

compressed air as a power source), and a blower supplied air knife (using an electric motor

as a power source) Each system consisted of two twelve inch long air knives Th e following

comparison proves that the EXAIR Super Air Knife is the best choice for your blowoff ,

cooling or drying application.

Th e goal for each of the blowoff choices was to use the least amount of air possible to get the

job done (lowest energy and noise level) Th e compressed air pressure required was 60 PSIG

which provided adequate velocity to blow the water off Th e blower used had a ten horsepower

motor and was a centrifugal type blower at 18,000 RPM Th e table at the bottom of the page

summarizes the overall performance Since your actual part may have an odd confi guration,

holes or sharp edges, we took sound level measurements in free air (no impinging surface).

Drilled Pipe

Th is common blowoff is very inexpensive

and easy to make For this test, we

used (2) drilled pipes, each with (25)

1/16" diameter holes on 1/2" centers

As shown in the test results below, the

drilled pipe performed poorly Th e initial

cost of the drilled pipe is overshadowed

by its high energy use Th e holes are

easily blocked and the noise level is

excessive - both of which violate OSHA

requirements Velocity across the entire

length was very inconsistent with spikes

of air and numerous dead spots.

Flat Air Nozzles

As shown below, this inexpensive air

nozzle was the worst performer It is

available in plastic, aluminum and

stainless steel from several manufacturers

Th e fl at air nozzle provides some

entrainment, but suff ers from many

of the same problems as the drilled

pipe Operating cost and noise level are

both high Some manufacturers off er

fl at air nozzles where the holes can be

blocked - an OSHA violation Velocity

was inconsistent with spikes of air

Blower Air Knife

Th e blower proved to be an expensive, noisy option As noted below, the purchase price is high Operating cost was considerably lower than the drilled pipe and fl at air nozzle, but was comparable to EXAIR’s Super Air Knife Th e large blower with its two 3" (8cm) diameter hoses requires signifi cant mounting space compared

to the others Noise level was high

at 90 dBA Th ere was no option for cycling it on and off to conserve energy like the other blowoff s Costly bearing and fi lter maintenance along with downtime were also negative factors.

EXAIR Super Air Knife

Th e Super Air Knife did an exceptional job of removing the moisture on one pass due to the uniformity of the laminar airfl ow Th e sound level was extremely low For this application, energy use was slightly higher than the blower but can be less than the blower if cycling on and off

is possible Safe operation is not an issue since the Super Air Knife can not be dead- ended Maintenance costs are low since there are no moving parts to wear out.

The Super Air Knife is the low cost way to blowoff, dry, clean and cool.

If you think compressed air is too expensive and noisy - read this The facts will surprise you!

Blowoff Comparison

Comp Air Horsepower

Required

Sound Level dBA

Purchase Price

Annual Electrical Cost*

Approx Annual Maintenance Cost

First Year Cost Type of blowoff PSIG BAR SCFM SLPM

Drilled Pipes 60 4.1 174 4,924 35 91 $50 $4,508 $920 $5,478

Flat Air Nozzles 60 4.1 257 7,273 51 102 $208 $6,569 $1,450 $8,227

Blower Air Knife 3 0.2 N/A N/A 10 90 $5,500 $1,288 $1,500 $8,288

Super Air Knife 60 4.1 55 1,557 11 69 $518 $1,417 $300 $2,235

*Based on national average electricity cost of 8.3 cents per kWh Annual cost refl ects 40 hours per week, 52 weeks per year.

RS# 104

A new Agilent application note,

“Wireless LAN at 60 GHz,” discusses

in detail the proposed IEEE 802.11ad

guidelines for devices that would

provide up to 7 Gbps throughput

using approximately 2 GHz of

spectrum at 60 GHz over a short

range It addresses the requirements

and challenges of the higher data

throughput needed to support

today’s “unwired office.” Download a

copy at www.agilent.com/find/WLAN.

Capping-clutch Web site

Warner Electric’s new Web site,

www.cappingclutch.com, provides

a comprehensive resource

for improving bottle-capping

operations The site covers magnetic

headsets that provide consistent

torque control; fixed, quick

connect, and mechanical chucks;

and stainless-steel antirotation

knives Content includes product

information, design features,

brochures, catalogs, application

profiles, and video links — covering

applications from milk cartons and

bottled water to ketchup and motor

oil.

Metric mechanical-drive products

Stock Drive Products/Sterling Instrument’s new D805 Metric

Catalog includes detailed specs and information on more than 40,000 drive components, including timing belts, pulleys, clamps, bearings, gearheads, couplings, and vibration mounts, many of which are RoHS compliant The 1,264-page catalog also contains a comprehensive 233-page technical data section Download or request a

hard copy at www.sdp-si.com/D805/

D805cat.htm.

YouTube training channel

Wago Corp.’s new YouTube channel

features more than by-step training and product support videos that cover a broad spectrum of content on electrical interconnections and automation

30 step-Topics range from basic block marking to commissioning a Bluetooth RF transceiver, remote I/O EtherNet/IP fieldbus, and CoDeSys programming The videos include instructional text, letting users follow along with their own computer

terminal-Access the channel at www.wago.us

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examine how these methods can solve specific application challenges, when

one technique is preferred over another, and cases where a combination of

techniques provides the best results Servotuning can help simplify designs,

improve throughput and performance, increase component life, and reduce

machine commissioning time Learn more and register at http://machinedesign.

com/training.

Ball-shaped robot

Engineers from STMicroelectronics

show off the Sphero, a small robot that looks like

a baseball It houses a motor, drive, battery, MEMS sensors and, via

Bluetooth, uses an iPad for steering and control Learn

more and watch it roll at www.engineeringtv.com/video/

Fun-Applications-for-STMicroele.

UPCOMING WEB EVENTS

WATCH PRODUCT OVERVIEW

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AutomationDirect’s

YouTube channel features

industrial-control product overviews and tutorials Recent uploads include:

Field wirable connectors

— Two helpful videos on the components and how to wire them

Temperature controllers

— Overview of alone process/temperature controllers with universal signal inputs

stand-Soft starters — Features of

soft starters that can help save energy and increase motor reliability

NFPA pneumatic cylinders

— Features and applications for the latest addition to the NITRA pneumatic-cylinder family

For a complete list of videos,

visit www.youtube.com/ automationdirect Become

a subscriber and get alerts when new videos are uploaded

MAY 10, 2012 MACHINE DESIGN.com

6

You can’t blame the Indians for taking advantage of “free money.” But the process by which they came to install a wind turbine is a snapshot

of the unhealthy situation that characterizes the wind industry: Unless installed by hobbyists, most wind turbines are built only because of sub-sidies, not because of economic feasibility Consider the comments of

the Texas State Energy Conservation Office a few years ago which

con-ceded, “For wind farms being installed today, the production tax credit

is still the main driver of economic viability.” The PTC is a corporate tax credit for several renewable sources, including wind, which credits 2.2¢/kW-hr for electricity generated by wind power Wind producers have even been known to pay users to take their energy just so they can get the PTC

If there was ever an energy source in need of technological progress

to be economically viable, it is wind power That is why we devoted a few pages in this issue to looking at novel designs for wind turbines Readers will note none of these ideas come from mainstream wind-turbine manu-facturers Turbine makers today seem to act a little like Detroit automak-ers of the 1970s and 80s: Despite criticism of their designs, they’d rather push the models already in their brochures than go back to the drawing board to come up with something better

The wind-turbine designs we highlight are products of independent inventors who have noted the many difficulties of commercial wind-tur-bine architectures In particular, they have tried to devise ways of fielding wind turbines that are less costly and more reliable than those that occupy wind farms today

A case in point is the wind turbine now adorning the Indians’ home

field Designed by Dr Majid Rashidi of Cleveland State University, it is

a noncommercial prototype that uses a cylindrical structure with a cal shape to deflect wind into small-scale turbines on its sides This lets Rashidi’s turbines begin turning in light breezes that wouldn’t budge the blades on most other designs They are essentially noiseless thanks to dif-fuser rings that reduce the wind currents traveling along the blades And the design uses inexpensive materials that are easy to find and relatively simple to assemble

heli-Proponents of the wind industry have predicted dire consequences if legislators fail to extend wind’s production tax credit But their arguments begin to sound like those of automakers and their Armageddon-like pro-nouncements about CAFE standards decimating their industry Wind-turbine makers would be better served listening to some of the inventors who want to make wind power practical without spending other people’s money to subsidize it

— Leland Teschler, Editor

RS# 107

MAY 10, 2012

Most axial fans of the “compact class” use the old shaded-pole motor AC technology, despite its poor efficiency compared to DC technology The barrier to improvement was that DC technology couldn’t be operated directly from the AC mains supply A solution is now available with i-Maxx technology from ebm-papst The i-Maxx retains the mounting dimensions of the equivalent AC fans and is capable of operating on AC mains power around the world There is no simpler way

to save energy.

Learn more at info.ebmpapst.us/i-maxx

the engineer’s choice

Intelligent fans for smart savings.

RS# 108

We’ve Covered All The Angles

-Without Contact

With more than a thousand different series, models, sizes, and options there is a Novotechnik non-contact rotary position sensor to match your application, and there’s one very good

reason to choose Novotechnik: A level of precision that’s unmatched in

the industry Whether you’re looking for non-contacting, or even touchless,

single-turn, or multi-turn rotary position sensors, Novotechnik has the sensor you

need They are all detailed in our 96-page rotary position sensor catalog For your

free copy, contact Novotechnik.

Setting A Higher Standard:

• Operating lives to: unlimited movements

• Independent linearity to ± 0.3º

• Resolution to 0.09º

• Repeatability to <0.03% of signal range

• Sealed to protection class IP 69

We’ve Covered All The Angles

-Without Contact

Novotechnik U.S., Inc.

155 Northboro Road Southborough, MA 01772 Tel: 508-485-2244 • Fax: 508-485-2430

For complete information, visit

MANAGING EDITOR

Kenneth J Korane ken.korane@penton.com

SENIOR EDITORS

Leslie Gordon leslie.gordon@penton.com Stephen J Mraz stephen.mraz@penton.com

1300 E 9th St Cleveland, OH 44114-1503

RS# 110 RS# 109

MAY 10, 2012 MACHINE DESIGN.com

10

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Them kids

I graduated from college 30 years

ago, and about every two years

after that, I read at least one

ar-ticle about college graduates

be-ing unprepared for the workforce

(“Old Codgers Always Gripe About

‘the Kids,’” March 8) The articles

are usually written by academics

from places like the Social Science

Research Council But they just

want to extract more education

funding from the government If

the premise of the articles is true,

however, then it is an

embarrass-ment to academia to advertise

such poor student preparedness,

considering the astronomical

sal-aries and benefits teachers and

professors receive

The argument that college

graduates are not prepared for

the workforce also comes from

managers in all industries When

asked about this issue, one

dis-covers that managers expect new

hires to jump in and know all the

systems and procedures of their

company This is too much to

ex-pect from any new hire, especially

from recent college graduates I

find that some engineering

man-agers have even higher

expecta-tion from new college graduates

They expect them to know and

have experience in all advanced

manufacturing processes, in

ad-dition to being able to jump in

and create new designs

As you pointed out, the idea

that new college grads are not

being properly educated to join

the workforce will be around for a

long time, along with other myths

espoused by academia such as the

one that says engineers lose half

their knowledge every five years

after graduating from college

Twelve of the engineering

text-books that I used in my studies 30

years ago are still in print today

What new laws of physics are new

engineers learning, making the

old engineers obsolete? Please

do not publish such absurd ideas

without real proof

of the labor market in the U. S for engineers

Anyway you look at the ation, it becomes clear that the root cause of the problem is the loss of manufacturing in the U. S

situ-causing the reduction in demand for materials and services

This trend has been going on for more than two decades, and

it is time we admit that ization is not working for us and will never work in our favor Most

global-of the calls to level the playing field with tax cuts and incentives are just more smoke and mirrors sponsored by corporations al-ready making billions of dollars despite the deterioration of the take-home pay and standard of living of American engineers and workers in general

There is no silver bullet or a simple solution to decades of failed industrial policies, but a fair-trade policy that protects American jobs is required to stop,

or at least slow, the further rioration of our labor market

dete-Name withheld by request

Quality not quantity

I recall having a related discussion with engineering educators about

10 years ago (“Deconstructing Engineering Education,” Leland Teschler’s Blog, Feb 22) A few years before that, around 1997, many universities essentially junked a full year of engineering curriculum to squeeze in a full year of “design courses.” I asked educators how they managed to still teach the essentials and get

it all done in four years of work They said they got rid of overlap by combining parts of classes to eliminate several sepa-rate classes It seems they didn’t see the value in courses that re-peated some materials, but in a different approach

course-Many critics of current neering education seem to have

engi-a single complengi-aint: “Engineering courses are too hard!” But then, they are supposed to be hard That’s what produces great en-gineers

Engineers have an awesome responsibility to society; repeti-tion and “hard” are absolutely necessary to produce those great engineers that we need “More engineers” is not a worthwhile goal, while “the best engineers in the world” is the only goal worth pursuing

Scott Prost-Domasky

Kids and baseball:

They never change

The establishment, to use an old 60s term, is always harping on the col-lege grads, complaining they aren’t

as educated or qualified as they themselves were at that age But one reader points out that the older gen-eration never seems to take respon-sibility for educating and training those college grads In another vein, readers agreed with Ken Korane’s sa-tiric plea for Congress to mandate strike-zone-detection technology for major-league baseball

MAY 10, 2012 MACHINE DESIGN.com

12

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RS# 112

When I was at Purdue, there was

a story making the rounds that the Indiana legislature discussed passing a law that would man-date that pi equal three, since the real value was too hard to re-member

Buck

I’ve heard rumors the new porate Average Fuel Economy (CAFE) mandate will include an antigravity provision that vehi-cle manufacturers must meet by 2050

Cor-Ellen Hellman

Correction

In the March 22 Looking Back item,

“Rough-water power boats,” the sentence “Speed is 20 knots with

an 180-hp outboard,” should have read, “Speed is 20 knots with an 18-hp outboard — Editor

man error from calling balls and strikes is long overdue

Frank C Maffei

I recall a small hometown game

ye a r s a g o w h e n t h e u m p i r e called a strike on my father when the ball bounced off the front edge of the plate The ump’s ar-gument was that as the ball went

by the batter, it was in the strike zone My father was deep in the batter’s box As it turned out, the ump had a substantial bet on the game

M a y b e u m p i r e s c o u l d b e rigged with cameras so we could all see exactly what they see Sort

of an instant replay And the ump could review the pitch before making the call

All in all, I don’t support ing high tech to baseball Over the course of nine innings, it usu-ally all balances out

add-Carl Junior

One problem with keeping

stu-dents in engineering is that they

do not relate what they are

learn-ing in early courses to practical

en-gineering What is needed is more

hands-on experience early in the

curriculum to show them the need

for what they are learning

Lawrence Mann

Strike zone technology

and a new pi

In reference to your commentary

(Mandating Innovation, Feb 9):

I have been advocating the use

of modern technology to

deter-mine and police the strike zone

in major-league baseball Umps

have needed it for many years

now I want to explode when I

hear the argument that doing so

would remove the “human

ele-ment” from the game Only when

the players are robots will such a

statement be true Removing

hu-RS# 113

SCANNING FOR IDEAS

Edited by Stephen J Mraz

Request free information vi

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Magnetic brakes have suffered from

hysteresis, cogging, and low-power

output for over 30 years And they

have lacked linearity, so users

had to more than double

the input signal to double

the output force of the

brake To solve these

problems, engineers at

Magnetic Brake

Sys-tems, Camarillo, Calif

The same

microcon-troller eliminates cogging

which, on some magnetic

brakes, can be as high as 25%

of the brake’s maximum torque The

microcontroller ensures that within

500 msec after the input signal goes to

zero, cogging disappears — and with

no rotation of the brake drag ring

The brakes can exert constant

ten-sion instead of constant torque, which

is useful for unwinding wire or films

from variable-diameter feed rolls To

do this, the microcontroller monitors

the radius of the feed roll by measuring

the time between pulses created by

Hall-effect devices and magnets on the

feed spindle and metering roller

The brakes use an internal,

centrifu-gal cooling fan and ventilation slots

to keep the brakes cool For example,

the MBL-5.5, with a 5.5-in OD, can

dissipate 4,700 W for 10 sec; on a tinuous basis, it can dissipate 1,700 W

con-at 8,000 rpm The brakes come with outside diameters ranging from 1.5 to

12 in., and handle 4,000 to 20,000 rpm

The brakes are powered by a 24-V power supply

Coil Ball bearings

MAY 10, 2012 MACHINE DESIGN.com

16

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RS# 115

How do you

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N. Y (www.ultramotion.com), is

based on an in-line design that

couples the motor directly to the

leadscrew This makes for a

com-pact package, one that measures

5.4-in long when equipped with a

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long when a NEMA-23 stepper

mo-tor is used Coupling the momo-tor to the leadscrew with an Acme or ball nut gives the actuator more accu-racy and a longer life

Repeatability of the Digit is

±0.00004 in., and resolution is 0.00004 in./step The device can exert up to 400 lb of force and move at up to 15 ips

aluminum housing

Anodized-Wiper seal

Polished steel shaft

stainless-O-ring seal

Bidirectional of-stroke-seal Acme or ball nut with optional

end-antibacklash feature

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RS# 117

REPORTER’S NOTEBOOK

and throughput by

offering part storage,

automated selection, and

shipping that costs less and uses

less labor

Conventional ASRS have been

storing and retrieving cases containing

identi-cal parts for some time They have recently been

expanded to handle small-quantity orders of several

different items However, several factors limit the

ef-ficiency of these systems First, they often experience

single-point failures that halt the entire store-and-pick

operation Second, they cannot easily be expanded

to match the growth in shipments This is particularly

true regarding the ability to independently scale

throughput and inventory during installation and

over the life of the system Third, the need to store and

retrieve orders sequentially instead of simultaneously

limits speed and efficiency in handling orders on a

high-throughput basis

New designs for piece picking have overcome

these deficiencies, boosting order-processing speed

without sacrificing accuracy In addition to high

throughput and cost-efficient distribution, this new

machinery also supplies a higher density of storage

and more modular flexibility, which promotes

enlarg-ing the system as needed

This new approach is typified by the AutoStore

system from Jakob Hatteland Logistics AS in

Nor-way AutoStore uses independently operating robots that move bins from a grid layout to individual pick stations The distribution center’s immediate needs dictate the number of bins installed But system flexibility accom-modates future growth by making it easy to add more bins for more storage

Each robot travels on two sets of wheels that let it move along perpendicular axes Thus, all robots can reach any position and any bin on the grid, indepen-dently of other robots And if one of the robots needs maintenance, for example, its tasks are automatically taken over by other robots

The system accommodates almost any number of robots, and the number of robots determines overall throughput Each robot has a lift for picking up, car-rying, and placing bins stored in the grid The robots wirelessly communicate with a warehouse-manage-ment system (WMS), and pick stations through a stan-dard application interface

Robots deliver each bin to a pick station where workers pick, place, or check inventory The robot

ule with near-zero errors while

coping with a growing variety

of stock numbers and

complex orders

To address this

situation, new

automated-stor-age and retrieval

systems (ASRS) try

to balance

inven-tory complexity

Many high-throughput retail-distribution centers face

a growing logistics challenge: how to prepare small

quantities of diverse parts to ship and arrive on

sched-MAY 10, 2012 MACHINE DESIGN.com

20

A camera that can see around

or ceiling outside the room Some

of the laser beam reflects off that surface and into the room, where it continues to bounce off objects and walls Some of the light reemerges and strikes a photodetector that takes samples every few picoseconds (trillionths of a second) Like radar, the device measures the time it takes for reflections to return, which lets

it calculate how far the beams have traveled

The device repeats this process several times, angling the laser off

different spots on the wall Travel times from several laser bursts are assembled using various algorithms, including filtered backscatttering,

a technique commonly used in CAT scans This lets the device piece to-gether the geometry of the room In tests, images are said to be blurry but easily recognizable

Once improved, the device could

be a tool for police or firefighters ing to determine if it‘s safe to enter

try-a room It could try-also be used by try-a vehicle’s nav system to peer around corners, and in medical endoscopic cameras to see otherwise hidden ar-eas inside the human body. MD

then returns the bin to storage New bins are thereby

delivered back-to-back so that operators rarely wait

for one

AutoStore holds approximately 30 min of live

pick-ing tasks in its queue at any one time Should the need

arise, any order can be redirected to any pick station to

improve throughput Control panels at each pick

sta-tion display status informasta-tion for the current order

Using a modular approach lets storage bins, robots,

and pick stations be expanded or extended Size and

form are no restrictions, as the system can adapt to

different building heights, levels, and even surround

obstacles such as pillars or walls

The system places goods in the grid so that

fre-quently used products are towards the tops of the

stacks Seldom-used bins sink to the bottom This

leads to shorter access times by reducing the distance

between commonly used parts

As each bin stacks on top of the other, the system

produces up to 60% better use of space than other

ASRS, and 300% better than conventional rack

sys-tems Typical installations may see up to 87% of the

available cube space used for storage. MD

Each AutoStore autonomous robot uses two pairs of wheels

for XY motion along guide rails Robots receive operating

instructions from a warehouse controller via a wireless

network Any robot can retrieve any container and take over

tasks from other robots in the event of malfunctions.

state and make neutrons in the nucleus vibrate cisely The ions need to be kept at temperatures in the 0.01°K range, a task usually handled by lasers for achieving ultralow temperatures (Bombarding atoms with a properly tuned laser lowers the temperature

pre-by forcing atoms to absorb photons, along with their

causing them to drift by at least 4 sec/14 billion years

(the estimated age of the universe) The new clock will

use heavier neutrons, which should be less affected by

these fields

A laser in the clock operating at 1015 Hz will boost

the nucleus of a thorium 229 ion to a higher energy

New clock will be incredibly accurate, losing 1 second every 14 billion years

Research scientists at Georgia Tech make adjustments to the overlapping laser beams used to

cool trapped atoms (Credit: Gary

Meek)

Researchers are

designing a nuclear

clock that would be

two orders of

magni-tude more accurate

than the most

ad-vanced atomic clock

The new clock

will base its time

keeping on the

oscil-lations of a thorium

ion’s nucleus Atomic

clocks use

oscil-lating electrons to

keep time, but these

relatively light

sub-atomic particles are

affected by magnetic

and electrical fields,

RS# 118 MAY 10, 2012

MACHINE DESIGN.com

22

momentum, which slows or cools the atoms.) But

bombarding the ions with a second laser to cool them

would affect the accuracy of the clock To get around

this problem, researchers will include a thorium 223

ion with the 229 ion The heavier, time-keeping ion will

be unaffected by a cooling laser tuned to the lighter

ion‘s frequency, but because of its proximity to the lighter ion, it will be cooled as well without degrading its vibrational frequency

The major challenge facing the research team is determining the laser frequency needed to excite the thorium nucleus, and scientists have spent 30 years looking for that frequency

The team includes scientists and engineers from

the Georgia Institute of Technology, University of Nevada, and University of New South Wales, Aus- tralia MD

An ultrahigh vacuum chamber houses the

RF ion trap where a single thorium atom is suspended and laser- cooled to near absolute zero temperature

develop-on Mars that aren’t in the sunlight because these shaded areas are more likely to have water (ice) near the surface than ar-eas exposed to sunlight, and finding water would change NASA’s plans for exploring Mars These areas are also colder than those exposed to sunlight, which reduces battery capacity So today’s rovers have limited time — any-where from a few hours to

a few days — to explore shadowed areas But a fuel cell could power a rover for weeks at time, despite the cold and darkness

Fuel cells used in space tion use hydrogen and pure oxygen, whereas those built for use on Earth rely on hydrogen and air, though only the oxygen from the air is re-ally needed Using pure oxygen eliminates the need to get rid of im-purities found in air This is one way NASA can boost fuel-cell efficiency

explora-In the pursuit of efficiency, the space agency also uses a nonflow-through cell, which means capillary action wicks away water produced

by the electrochemical reactions that generate electricity Conven-tional flow-through cells need a pump to handle this task, which adds weight, takes up space, and is less reliable

And although it seems dictory, NASA’s nonflow-through

contra-cells are larger and heavier than conventional fuel cells This lets NASA use higher pressures and temperatures inside — about 70°C and 45 psi for both the hydrogen and oxygen, compared with just

a few pounds/square inch over ambient and room temperature for conventional cells All these factors make the rover cell more efficient

at converting hydrogen and water

to electricity So the larger size and weight of the NASA cell is offset by the additional electricity it can ex-tract from the store of water carried onboard the rover or spacecraft

NASA can also configure a rover

to use solar panels to generate electricity for converting water to hydrogen and oxygen through electrolysis The rover would use the hydrogen and oxygen to re-supply the fuel cell’s reactant tanks and extend its power generation capability. MD

NASA develops fuel cells for planetary rovers

RS# 120

Resources:

NASA Glenn Research Center,

www.nasa.gov/ centers/glenn

MAY 10, 2012

QFSGPSNBODFDBOCFDPNQSPNJTFE (03& Ë 8JSFBOE$BCMFT PGGFSUIFCFTUTPMVUJPO

Researchers at the Fraunhofer Institutes for

Me-chanics of Materials IWM and Production Systems and Design

Technology IPK in Germany have developed a way to use shot

peening to straighten thin, distorted ceramics for parts such as leaf

springs They fire shot or small pellets at the surface of a component

with a blasting gun The shot strikes the surface and alters the shape

of the thin, outermost layer By moving the gun over the ceramic part

along a precisely calculated path, researchers counteracted warping

“Shot peening is common for working metals,” says IWM manager

Wulf Pfeiffer “But it has not been feasible for ceramics because they

are too brittle and would shatter.”

Researchers analyzed which size shot might work on ceramics

Pellets that were too big would destroy the surface Pellet speed was

also a factor because hitting the material too fast damages it while

hitting it too slowly does not change the surface shape enough

Before making a new component, researchers determined what

to expect of particular ceramics They fired shot and measured the

stresses to see what sort of deformation is feasible and how the

beam should be directed

Ceramics are useful in industry because they are lightweight,

rigid, resist corrosion, and withstand higher temperatures than metal

(over 500°C) Until now, however, ceramics could only be machined

using costly diamond tools And machining creates tensions in the

material’s surface, which distort the finished part as soon as it is

re-moved from the machine

Fortunately, the capability to shot peen the material has let

re-searchers create various prototypes, including a ceramic leaf spring

and a concave mirror The technique is now advanced enough to

serve in series production for simple components Researchers

have developed a computer simulation that will let components be

worked in multiple axes They also hope to automate the process

us-ing a robot. MD

The cylindrical, 16-cell, flow-through fuel cell developed by

NASA for spacecraft and planetary rovers was tested in NASA’s

Scarab, a testbed for rover technology.

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Sterilizers have automatic timers with heat “hold”

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for the Navy’s new DDG-51 class of

multipurpose guided-missile ers RCA will design a balanced combat system that integrates anti-air, anti-submarine, strike, and surface-warfare capabilities As many as 60 ships of this new class are planned in a program that may continue to the year 2000

destroy-50 YEARS AGO — 1962

Stainless-steel-clad aluminum can

be fabricated without separation or deformation and joined by various methods, including welding, brazing,

soldering, and adhesive bonding The material, designated C908 by the

Aluminum Co of America, is a

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MAY 10, 2012 MACHINE DESIGN.com

26

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RS# 122

COMPANY NEWS

CERTIFICATIONS

The testing and

certifica-tion organizacertifica-tion, TÜV SÜD

America, Peabody, Mass.,

can now provide accredited

certification for ISO 50001

to companies of all sizes and

complexities

DISTRIBUTION Conabelt USA, Miami, a dis-

tributor of engineered ber products, has agreed to distribute industrial belts for

rub-ContiTech North America,

Montvale, N. J., into Latin

America ContiTech Group,

a div of Continental AG, is

comprised of seven ized operative business units

special-TRAINING PROGRAMS TÜV Rheinland, Boxborough,

Mass., will hold a four-day Functional Safety Training Program from June 18 to

21 at its Chicago office The program is designed for engi-neers and developers of pro-grammable electronic safety systems and products who want to deepen their knowl-edge and experience within the area of functional safety according to IEC 61508 The program includes three days

of training, and participants can take an optional exam on the fourth day to obtain an official verification of their expertise To register or learn

more, go to http://education tuv.com/tuv-functional-safety- program.

DISTRIBUTORS

Automation-solutions

pro-vider iAutomation, Beverly,

Mass., has expanded its uct portfolio through a new channel partner agreement

prod-covering Dunkermotor’s

frac-tional-horsepower brushed and brushless-dc motors and intelligent servomotors, as well as its Thrust Tube linear motors Dunkermotor, Elgin, Ill., manufactures industrial and commercial automation motors

NEW HEADQUARTERS NovaTorque Inc., a producer

of high-efficiency magnet motors, has moved from Sunnyvale, Calif., to new headquarters in Fremont, Calif

permanent-AWARDS United Technologies Corp.,

Hartford, Conn., has awarded

Simrit’s Tillsonburg, Ontario,

Canada, facility its Supplier Gold status for outstand-

RS# 123 MAY 10, 2012 MACHINE DESIGN.com

28

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RS# 124

tree, Mass., has opened its

first assembly plant in China Bauer, located in Esslingen, Germany, manufactures high-quality gearmotors

TEST EQUIPMENT SigmaTron International Inc.,

Elk Grove Village, Ill., has opted the Agilent i1000D diag-nostic test set (DTS) application and the TS-8900 functional test

ad-system from Agilent gies Inc., Santa Clara, Calif., to

Technolo-reduce test costs and increase business Agilent offers mea-surement solutions in chemical analysis, life sciences, electron-ics, and communications SigmaTron is a contract elec-tronics manufacturer

INVESTMENT Omron Automation & Safety, Schaumburg,Ill., has invested in TEN Media LLC,

a technology company that provides egg producers, su-permarkets, and consumers with solutions to aid in the prevention of salmonella disease and food-borne ill-nesses associated with table eggs Omron will provide the automation technology to the network TEN Media is build-ing the first nationwide, fully integrated compliance verifi-cation and quality-assurance network capable of defending all U. S egg production MD

NEW BRANCH OFFICE Moog Industrial Group, a div

of Moog Inc., East Aurora, N. Y.,

has opened a branch office in Istanbul, Turkey Moog designs and manufactures high-perfor-mance motion-control compo-nents and systems

ing performance in delivery,

quality, lean practices, and

customer support The

facil-ity is one of only five original

Gold Supplier recipients to

maintain this status for three

consecutive years

RS# 125 MAY 10, 2012 MACHINE DESIGN.com

30

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SENSOR SENSE

Inductive

position-measuring sensors

target and the sensor As that gap is typically 1 mm or less, the buildup of

particles may easily exceed that spacing, producing drag and wear on the

sensor as the particles are pulled across the surface

In addition, permanent magnets lose their strength over time,

especially when exposed to high temperatures If the application

involves high-temperature work, the target magnet may need constant

replacement

Though IPMS targets are made of ferrous materials, they are not

magnetized So one immediate advantage is that they don’t attract

metallic chips and there’s no worries of high temperatures demagnetizing

the material In addition, the air gap between target and sensor can

approach 6 mm when used with appropriately sized targets

Typical resolution for this type of sensor is 0.125 mm in linear travel or

0.4° if used in a rotary sensor Both versions provide nearly limitless cycles

of operation

Besides the analog output, the internal microprocessor can be

programmed to give switched output setpoints In other words, the

output can turn full-on or full-off when the target reaches a specific

setpoint Setpoints and travel spans can be changed with no recalibration

MD

Pepperl+Fuchs (www.pepperl-fuchs.us) supplied information for this column.

Edited by Robert Repas

RS# 128

Ferrous target Internal inductive

sensors

Inductive measuring sensor

position-Inductive position-measuring systems (IPMSs) operate on the same

principle as an inductive proximity sensor But instead of a single sensing

coil, position measuring uses a multiple-coil system The outputs from

each coil go to a microprocessor that analyzes and compares the

sensing-coil output and determines the position of a nonmagnetic ferrous target

based on the relative signal strengths from each coil The microprocessor

then outputs the position of the target as either a distance-proportional

current of 4-to-20 mA, or a voltage signal from 0-to-10 V Note that the

sensing coils may mount in either a linear or circular pattern, depending

on the type of location sensing desired

Many noncontact

posi-tion-measurement systems

use magnetic or

inductive-magnetic principles of

op-eration Their target must be

a permanent magnet,

as the sensor

de-tects the target’s

magnetized targets can

attract metallic particles

that build up between the

MAY 10, 2012

Inductive position-monitoring sensors compare the outputs from multiple inductive proximity sensors

to determine the position of the target on the sensor face.

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COMMENTARY

Back in January, I wrote a commentary asking why the vast majority of neers are dead set against joining or forming labor unions (“Time for engi-neers to think about unionizing? “Jan 19) Most of the answers I received fell into three broad categories:

engi-1.) We don’t need unions because we can negotiate compensation and working conditions for ourselves And if we don’t like our current job/employer, we can easily go out and find another

2.) Unions are selfish, don’t care about America, and are “destructive” to companies and the country We’re above all that

3.) And my favorite, paraphrased here: “You have

to be a spineless wimp to consider letting a union do your bidding.”

All of these responses led me to conclude that engineers are fiercely independent, loyal to com-pany and country, and insist on doing things themselves

But then we got the results back from our nual salary survey A section of it asks engineers about workplace gripes and what they don’t like about the profession Almost a quarter of the respondents said their compensation packages were poor, 17% mentioned long hours with no provision for overtime pay, 33% said they were forced to do too much nonengineering work, and half saw their health-care costs climb

an-These complaints sounded much like the sues unions try to address in their contracts when negotiating with manage-ment And usually, unions get contracts giving them at least half of what they want, sometimes much more This has become less common in the current economy where even unions have taken hits However, it still seems

is-as though unions get better deals from companies and employers than folks

in nonunion shops

But is this really true? Statistics can shed light on the situation

Specifi-cally, the Bureau of Labor Statistics keeps figures on the weekly earnings of

full-time and salaried workers broken down by occupation and whether or

not workers are represented by a union (tinyurl.com/3dpvv66).

Turns out that those in architecture and engineering occupations who are represented by unions earn a median salary of $1,325/week Those not represented by unions pulled in a median of $1,314/week, or $11 less (For comparison, the difference was $33 last year, still favoring those with union representation.) But when you add in the dues paid by union members

(about $40 for SPEEA, the engineering union at Boeing), the result is a

probably a wash

The moral of the story: When it comes to salaries, engineers are like most other people, they want more And with or without a union, you’re going to take home roughly the same amount MD

Union or not, engineers’ salaries are about the same

Stephen J Mraz

Senior Editor

“ …Engineers are fiercely independent, loyal to company and country, and insist on doing things themselves ”

RS# 129

MAY 10, 2012

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RS# 130

BERKE ON SAFETY

create as many as 3 million jobs by the end of this decade Problem is, indications are that this welcome trend could lead to a severe shortage of skilled workers Virtually every person on a factory floor will be valuable and hard to replace.All the more reason, then, to take steps that minimize the possibility of worker injuries But sometimes equipment designs can only do so much to promote an injury-free workplace Operational norms can be just as important for keeping workers well and on the job

This is particularly true for an aging workforce, a fact of life in the U. S with its Baby Boomers As people get older, they need to spend more time loosening up and stretching before exercising That is why many companies conduct calisthen-ics, on the clock, for their factory workers Too many of us put ourselves in high-energy situations without taking the proper precautions

A story helps illustrate the point While in college many years ago, I was a skydiver During my 26th jump on a December morning in Minnesota (ground temperature 0°F), and without any stretching before boarding the aircraft, I broke

my ankle on landing When I healed and the weather warmed up, I jumped again into a plowed field and broke my foot This time I had done a few minutes of stretching first

Since then, I have always stretched and loosened up, but on occasion would still injure myself Recently I found out why: What I was doing was exactly wrong

Bill Holcomb, Ph.D., professor of Athletic Training at the University of Nevada, Las Vegas, set me straight Extensive research shows that the worst thing one can

do is stretch cold muscles Holcomb has found that static stretches (meaning the kind where you hold the stretch before a workout or competition) actually reduce strength, power, and performance

He has come up with several tips on proper stretching techniques Among them: Always warm up first Stretch, but not when muscles are cold Do 5 min-utes of brisk walking or slow jogging “Warming up increases blood flow, which increases the temperature in the muscle, which makes the collagen fibers more elastic like a rubber band,” he explains

After warming up, do dynamic, not static, stretches Dynamic stretching means slow, controlled movements rather than remaining still and holding a stretch These include a goose-step march: Slowly lift your leg straight out in front

of you, alternating as you walk with your normal stride length This is also an fective hamstring stretch Also do knee lifts: Bring your knees up to or close to

ef-your chest as you jog or walk Finally, try a butt-kick: As you jog or walk, bend one

knee and lift it behind you as though you were trying to kick yourself in the butt.And never stretch to the point of pain Forget the phrase, “no pain, no gain.”

My stepson and son-in-law both began to subscribe to these principles once they suffered severe Achilles injuries after doing static stretching exercises My stepson suffered his Achilles tendon injury chasing a fly ball He now coaches his son’s soccer team and has his players do proper warm-ups before each soccer practice and game My son-in-law tore his Achilles tendon taking a first step in a touch-football game Now even before something as mundane as bowling, he goes through Holcomb’s warm-up and stretching program

The lesson: Workers should warm up and stretch before any activity where they may be injured, but they should do it properly

— Lanny Berke

Lanny Berke is a registered professional engineer and Certified Safety Professional involved

in forensic engineering since 1972 Got a question about safety? You can reach Lanny at lannyb@comcast.net.

Edited by Leland Teschler

Bad stretching can defeat good design

The Boston Consulting Group recently predicted that

reshoring of manufacturing operations to the U. S could

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MAY 10, 2012 MACHINE DESIGN.com

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VANTAGE POINT

Why aren’t more manufacturers embracing sustainable metalworking?

While environmental stewardship has become better understood and more widely accepted, many manufac-turers are still not taking the necessary steps to implement newer, proven production methods that foster sustain-ability Metalworking operations in particular have an obligation to embrace sustainable manufacturing processes that protect workers and the environment The good news: Such changes can generate substantial savings

One such technique is Minimum Quantity Lubrication (MQL) In cutting operations, MQL eliminates large quantities of water and oil-based cool-ants and replaces them with small amounts of lubricant mixed with air This air-oil stream is precisely metered and delivered to the cutting tool’s edge, and it has

metal-no adverse affect on machining speed or quality The philosophy behind MQL

is simple: more is not always better Use only what’s needed, because enough is

as good as a feast

MQL offers many benefits Workers are safer, both in the short and long term, because operators, skilled tradesmen, and engineers are no longer ex-posed to the toxicity, bacteria, and fungi risks that come with traditional “wet” machining, nor to the coolant mists that foul plant air The small amount of oil used for MQL is generally based on vegetables or esters, which are less harmful

to humans

The environment stays cleaner because there are no used cutting fluids that require costly disposal And manufacturers don’t face the headaches of comply-ing with strict EPA regulations Metal chips produced during MQL machining are nearly dry, easier to recycle, and more valuable than chips generated with conventional approaches

MQL even helps change the “dirty” perception of manufacturing

Most manufacturers still associate sustainability with higher costs However, when we break down the investment in “wet” manufacturing systems, it’s clear they are expensive to build and operate A machine that uses conventional cool-ants requires costly supply, filtration, and mist-collection equipment to transfer, pressurize, and recycle coolant It demands more-costly plant infrastructure, has higher installation costs, and is more difficult and expensive to relocate And on-going expenses include energy consumption, chemical maintenance, fluid replenishment, and disposal of used cutting fluids

The metalworking industry consumes several hundred million gallons of fluids each year MQL produces an operating savings of approximately 15% over wet sys-tems, not counting savings on plant infrastructure, installation, and the like There’s

a cascade of cost savings when you take flood coolant out of machining

So with all of these benefits, one might wonder why more manufacturers aren’t implementing MQL and other sustainable-manufacturing processes Perhaps it’s fear of new technology or the associated cultural change? In most cases, we hide behind the myth that sustainability adds cost In the case of MQL, sustainability pays for itself

These questions pose a real challenge for our industry If we don’t have the courage to change our behavior and embrace a new idea like sustainability, we may miss the next real technology opportunity to restore American manufac-turing leadership — and no one can afford that MD

MAG (www.mag-ias.com) is a leading manufacturer of machine tools and manufacturing

systems for the aerospace, transportation, heavy equipment, oil and gas, and energy markets.

alternative-Edited by Kenneth J Korane

Doug Watts

Chief Technical Officer

MAG Americas

Hebron, Ky.

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