April 5, 2012 A Penton Media Publication Tune in to EngineeringTV.com NEWEST SAILOR: A FIREFIGHTING ROBOT, page 22 HIGH PRESSURES CHALLENGE PUMPSEAL DESIGNS, page 44 INTERNAL PERMANENT MAGNETS GIVE MOTOR DESIGN A NEW LOOK, page 56 Digital Edition Copyright Notice The content contained in this digital edition (“Digital Material”), as well as its selection and arrangement, is owned by Penton Media, Inc and its affiliated companies, licensors, and suppliers, and is protected by their respective copyright, trademark and other proprietary rights Upon payment of the subscription price, if applicable, you are hereby authorized to view, download, copy, and print Digital Material solely for your own personal, non-commercial use, provided that by doing any of the foregoing, you acknowledge that (i) you not and will not acquire any ownership rights of any kind in the Digital Material or any portion thereof, (ii) you must preserve all copyright and other proprietary notices included in any downloaded Digital Material, and (iii) you must comply in all respects with the use restrictions set forth below and in the Penton Privacy Policy and the Penton Terms of Use (the “Use Restrictions”), each of which is hereby incorporated by reference Any use not in accordance with, and any failure to comply fully with, the Use Restrictions is expressly prohibited by law, and may result in severe civil and criminal penalties Violators will be prosecuted to the maximum possible extent You may not modify, publish, license, transmit (including by way of email, facsimile or other electronic means), transfer, sell, reproduce (including by copying or posting on any network computer), create derivative works from, display, store, or in any way exploit, broadcast, disseminate or distribute, in any format or media of any kind, any of the Digital Material, in whole or in part, without the express prior written consent of Penton Media, Inc To request content for commercial use or Penton’s approval of any other restricted activity described above, please contact the Reprints Department at (888) 858-8851 Without in any way limiting the foregoing, you may not use spiders, robots, data mining techniques or other automated techniques to catalog, download or otherwise reproduce, store or distribute any Digital Material NEITHER PENTON NOR ANY THIRD PARTY CONTENT PROVIDER OR THEIR AGENTS SHALL BE LIABLE FOR ANY ACT, DIRECT OR INDIRECT, INCIDENTAL, SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OF OR ACCESS TO ANY DIGITAL MATERIAL, AND/OR ANY INFORMATION CONTAINED THEREIN RS# 101 Solutions you can trust Brands you can trust Rex® Falk® Link-Belt® Thomas® TableTop® Rexnord solutions are not just about a transaction To support your business, Rexnord delivers what’s needed to run a successful operation, including: t
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Installation, testing, maintenance and repair VOLUME 84 ISSUE APRIL 5, 2012 FLUID POWER FEATURES For the past three decades, there has been a steady increase in the demand for liquid-chromatography (LC) pumps that can handle higher pressures Users say higher pressures improve sample resolution and throughput rates, while manufacturers are keen to launch morecompetitive, cutting-edge devices Until recently engineers, working with seal suppliers, have been able to satisfy these requirements, and the increasing pressures have led to instrument and performance improvements of nearly 1,900% since the mid1970s As a result, countless life-improving drugs and diagnostic processes have been developed But over the past two or three years, the race for everhigher pressures has outpaced the industry’s ability to solve the complex challenges of generating and maintaining them Today, LC engineers face the formidable task of operating pumps reliably and consistently at and above 20,000 psi And due to limitations in material capabilities and current pump designs, they can no longer rely solely on a seal to get them there Fast-forward to 1982, and HPLC devices were operating at 3,000 psi Almost 10 years later, they reached the 8,000-psi milestone Further strides led to the 2004 introduction of UHPLC and instruments generating pressures up to 15,000 psi Adjustments to these designs let pumps reach their current operating ceiling of 17,000 to 19,000 psi Now, in pursuit of even higher resolution and productivity, the industry has its sights set on the next big pressure milestone: 20,000 psi and above To better comprehend what today’s LC pump engineers are up against, it’s helpful to think about how the 20K+ barrier equates to other applications In a subsea environment, for example, you’d have to descend nearly 8.6 miles before encountering this kind of pressure The reciprocating pistons that generate this pressure in an LC pump can also see some pretty rough treatment They can be small (less than mm in diameter), but their performance is similar to that of pistons in internal-combustion engines In regular service, they are expected to deliver over million leak-free cycles The pressure progression Beyond the seal Increases in LC-pump pressure have been evolutionary, not revolutionary Even though the science of LC dates back to the early 1900s, pressure wasn’t a critical component in the equation until 1970, when the late Professor Csaba Horváth of Yale Univ first introduced high-pressure liquid chromatography While the increasing pressures of LC have never been a simple challenge, the new requirements have stretched existing designs to their limits The life-sciences industry can no longer expect to reach its pressure goals by focusing only on better seal designs and materials Engineers must also consider changes to the pump and seal together Some items being looked at include: • Piston (plunger) diameter, material, and surface finish • The connection between the plunger and its drive mechanism • Plunger alignment during travel The number-one requirement is delivering accurate flow rates, and this goal is what determines the plunger diameter, stroke length, and speed This is an area where sealing and pump-operating requirements compete There’s a fine line between conditions for best sealing and the plunger performance needed to build cylinder pressure Here’s how to address some key considerations Authored by: Michael Binder Application Engineer Steven Twork Market Manager Analytical and Laboratory Automation Products Bal Seal Engineering Foothill Ranch, Calif Edited by Kenneth J Korane ken.korane@penton.com Drive mechanism Key points: Pistons are typically driven by a rotating cam or linear actuator These drives push the piston forward within the pump’s cylinder, building up pressure When designing the drive mechanism, it’s crucial to consider how the plunger attaches (floating or fixed), and to compensate for pulsations during pumping Speed and stroke length will vary plunger side loading, which can cause premature wear on the seal Synchronizing the pump linkage is also critical In rotary-cam driven plungers, a cam follower rides along the periphery of the cam The cam’s high spot (lobe) pushes the follower which, in turn, moves the piston forward To retract the piston, a return spring may be used If the plunger doesn’t return freely due to low spring force and high seal friction, the follower loses synchronization • Higher pressures improve sample resolution and throughput rate in liquidchromatograpy pumps • Various pump modifications can raise pressure capabilities • Pump engineers should work with seal suppliers experienced in thermoplastic seals and HPLC Resources: Bal Seal Engineering, www.balseal.com Breaking the 20K helps keep 20 Clutch century-old clock ticking Tower clocks are retrofitted with electric motors to reset the weights that power the clock mechanisms Liquidchromatographypump test facilities are critical for realworld evaluation of pump and seal prototypes in a variety of media and pressures BARRIER Seals alone won’t take highpressure pumps to the next level 44 MACHINE DESIGN.com APRIL 5, 2012 APRIL 5, 2012  44 the 20K barrier 44 Breaking Seals alone won’t take high-pressure pumps beyond 20,000 psi 52 Steel is up to the automotive challenge There’s a reason steel has remained the dominant material used in cars and light trucks The same reason will let steel survive the CAFE crunch of higher fuel economy your motor IQ? 56 How’s The quest for greater motor efficiency leads in many directions, with more than a few novel designs MOTORS TECHNOLOGY GUIDE How’s your MOTOR IQ? Electric motors are by far the most common method used to convert electrical energy into mechanical motion To provide motion, most motors use attraction and repulsion of magnetic fields to create the force needed for movement But the generation of those fields and their method of interaction gives rise to literally dozens of motor designs Think you know electric motors? Check your knowledge against these devices Case Rear housing Rear rotor Front-rotor assembly Bearing Ac-induction motors Shaft Axial stator/field Standard induction motors have pole assembly been in use for over 100 years and are Axial-field pole reaching the limit of improvements detailed view Interior permanentin both performance and cost In an magnet rotor induction motor, a stator winding wound on the outer frame of the motor induces a voltage into the conductors of the rotor The rotor voltage Winding Conical-shaped creates a current flow through the rosurface Magnet tor forming a magnetic field that interacts with the magnetic field of the stator to make the rotor turn This exploded view of the NovaTorque PremiumPlus+ PM motor shows the Induction motors have several special shape of the rotors and stator assembly The cone-shaped rotors hold inherent advantages First, they are the permanent magnets with the entire magnetic path concentrated within simple to build and are robust and the rotor and stator poles No flux flows through the motor frame like that which occurs with standard PM motors reliable Second, they naturally adapt to the load placed on the motor Current rises as the load increases while the motor’s natural slip accommodates torque Authored by: spikes Through agreements between motor manufacturers, induction motors John Petro come in standard sizes and mounts that promote interchangeability Vice President Engineering The primary speed of an induction motor is based on the frequency of the ac NovaTorque Inc power line, rather than the applied voltage This means for fixed-speed applicaSunnyvale, Calif tions, ac-induction motors can be driven directly from the ac-power line without Edited by Robert Repas the need for any electronic drive However, most applications can show sizable robert.repas@penton.com energy savings through the use of an electronic-drive module Key points: In applications where variable speeds are advantageous, a variable-frequency • Induction motors are simple to build, drive is mandatory for all but the smallest of induction motors Once a motor robust, reliable, adapt to the load, and drive has been added, though, the cost differential between an ac-induction motor come in standard sizes and mounts and that of a permanent-magnet motor becomes only the cost of the motor The • Permanent-magnet motors have higher cost of the drive for either motor type is pretty much the same efficiency and smaller size for the same Induction motors operated with an electronic drive can reach speeds four output power times that of the motor’s base speed while still maintaining a constant horsepower • Special cone-shaped rotors and stator-field This is possible because ac-induction motors not generate a fixed back or windings in IPM motors create a magneticcounter-EMF (electromotive force) in the rotor that builds up with higher rpms flux flow that parallels the motor shaft Upper speed limits are based purely on the mechanical design of the motor, with centrifugal force being the prime limiter Resources: 56 MACHINE DESIGN.com APRIL 5, 2012  NovaTorque Inc., www.novatorque.com 56 Access our Reader Service Web site to quickly find and request information on the products and services found in the pages of MACHINE DESIGN www.machinedesign.com/rsc MACHINE DESIGN.com APRIL 5, 2012 MACHINE DESIGN.com 45 AC TC-Frame          AC T-Frame IronHorse™ Premium Efficiency AC electric motors meet the requirements of the Energy Independence and Security Act of 2007 Starting at $155, the MTCP Series gives you a low cost of entry so you get a quicker payback on your investment All our Ironhorse motors are in stock and ready for same-day shipment; if your order is over $300, you get free shipping too! 1
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 http://bit.ly/adcmotors RS# 103 ON THE COVER A model from a steel-industry project shows where various lightweight steels can be used in electric vehicles DEPARTMENTS EDITORIAL The fallacy of more-productive manufacturing 10 EDITORIAL STAFF 12 LETTERS 16 SCANNING FOR IDEAS Self-compensating miniature shocks Industrial connectors for data, control, and power apps 20 REPORTER’S NOTEBOOK 30 LOOKING BACK 36 COMMENTARY How to spend $140 billion on R&D 38 BERKE ON SAFETY Ladders are still a safety issue 40 VANTAGE POINT Avoiding the pitfalls of export control 42 INVENTOR’S CORNER Holder lets smartphones take pictures of microscopic images SOFTWARE REVIEW 62 3D mouse lets users “fly” through designs 64 SOFTWARE PRODUCTS 66 PRODUCT SPOTLIGHT Bearings & guides 68 75 77 78 78 79 PRODUCTS AD INDEX BUSINESS INDEX CLASSIFIEDS BUSINESS STAFF BACKTALK MACHINE DESIGN.com For customized article reprints and permissions please contact: Penton Reprints, 1-888-858-8851, e-mail at reprints@pentonreprints.com or visit 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 N Zeeb Rd., P.O Box 998, Ann Arbor, MI 48106-0998, Ph: 734-302-6500 or 800-420-NAPC (6272), extension 6578 Permission to photocopy is granted for users registered with the Copyright Clearance Center (CCC) Inc to photocopy any article, with the exception of those for which separate ownership is indicated on the first page of the article, provided that the base fee of $1.25 per copy of the article, plus $.60 per page is paid to CCC, 222 Rosewood Dr., Danvers, MA 01923 (Code No 0024-9114/12 $1.25 + 60) Subscription Policy: MACHINE DESIGN is circulated to research, development, and design engineers primarily engaged in the design and manufacture of machinery, electrical/electronic equipment, and mechanical equipment To obtain a complimentary subscription see our Web page at submag.com/sub/ mn For change of address fill out a new qualification form at submag.com/sub/mn Printed in U.S.A., Copyright © 2012 Penton Media, Inc All rights reserved MACHINE DESIGN (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, $199; Canada/Mexico: one year, $159; two years, $239; All other countries: one year, $199; two years, $299 Cost for back issues are U.S $10.00 per copy plus tax, Canada $15.00 per issue plus tax, and Int’l $20.00 per issue Product Locator, $50.00 plus tax Prepaid subscription: Penton Media (MACHINE DESIGN), P.O Box 2100, Skokie IL 60076-7800 Periodicals Postage Paid at Shawnee Mission, Kans., and at additional mailing offices Can GST #R126431964 Canadian Post Publications Mail Agreement No.40612608 Canada return address: Pitney Bowes, P.O Box 25542, London, Ont., N6C 6B2 Digital subscription rates: U.S.: one year, $69; two years, $99; Canada/Mexico: one year, $79; two years, $119; All other countries: one year, $99; two years, $149 APRIL 5, 2012 POSTMASTER: Send change of address notice to Customer Service, MACHINE DESIGN, P.O Box 2100, Skokie, IL 60076-7800           
              
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#!"... profiles, data sheets, brochures, catalogs and service manuals, as well as selection guides and braking calculations Banner Engineering’s 2012 Product Catalog has 875 pages of information and data on the company’s sensors, lighting and indicators, machine vision, wireless, and machine safety lines It also contains application details and a selection guide that lets users compare features and performance Get... store, or www.FST.com MACHINE DESIGN.com Wittenstein’s Product Configurator now has a motor-to-gearbox option It includes a database of more than 7,000 motors and lets users design a gearbox based on application requirements It reportedly fills the gap between the company’s online Product CAD Generator and cymex servo-sizing software Learn more at www.wittenstein-us.com APRIL 5, 2012 UPCOMING WEB EVENTS... 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 10 MACHINE DESIGN.com RS# 110 APRIL 5, 2012 quietly thrives in harsh environments Extreme durability meets low db performance Outperforming Outlasting Outstanding Workhorse strong and church-mouse quiet, our complete line... while engineers are pro12 MACHINE DESIGN.com fessionals Last time I checked, there were no special lines in the unemployment office for professionals I also find the last line in Chris Page’s letter to be revealing Apparently, he can imagine an engineer being jealous of a union member, but considers it bad form to admit to it — Stephen J Mraz Your commentary in the January 19, 2012 issue of M ACHINE D... and early 80s about “ownership” of jobs have still, at this late date, not been learned by most of American Industry And these lessons are taught in almost every U. S MBA program RS# 113 14 MACHINE DESIGN.com APRL 5, 2012 American industrial engineers are constantly doing time studies to determine how to shave seconds off of fabrication processes, but they are seldom tasked by corporate executives to... online machinedesign.com NEED CAREER ADVICE? ASK THE EXPERT After a long career as an engineering consultant, author and speaker, CAD/CAM and automation expert Joel Orr is now coaching engineering professionals on issues such as career planning, starting a business, work/life balance, and overall productivity and satisfaction He answers your questions on engineering careers at http://expert.machinedesign.com/engineering-careers-management... They are constructed out of a self-extinguishing thermoplastic (UL94-VO), and operate in temperatures from –40 to 125°C They can also be surface mounted or installed on bulkheads RS# 402 18 MACHINE DESIGN.com APRIL 5, 2012
 
 

 

   


  
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64" RS# 106 Copyrights 2012 Apple Rubber Products, Inc All rights reserved EDITORIAL The fallacy of more-productive manufacturing Readers who have watched the U. S economy limp along for the past few years will probably recall... afloat, the union workers, just like government workers, keep getting raises and expanded benefits at the expense of their fellow workers “So why do you think engineers have avoided unions all these APRL 5, 2012 years?” Maybe they have compassion and like working as a team instead of just for themselves Sandra Permid Your editorial was a little confusing Autoworker unions have destroyed the U. S auto industry