Tài liệu Machine design, tập 84, số 05, 2012

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 do 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 5 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 2 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 2 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 [email protected] 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 [email protected] 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 do 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 2 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 8 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 4 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 [email protected] 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. N Nano Super A Air Nozzle for p precision blowoff Th Nano Super Air Nozzle The is the smallest available. EXAIR’s “precision blowoff” EX provides pr optimum air entrainment t i t ffor a di directed high volume, high velocity airflow. The compact size permits mounting where space is limited. www.exair.com/45/nano.htm E Efficient air guns, co comfortable grip Sa Safety Air Guns use engineered Air Nozzles en to provide superior pe performance. Safe operation is assure assured along with low air consumption and noise level. Many styles and nozzles are offered. Extensions and Stay Set Hoses are available. www.exair.com/45/sag.htm N Nozzle cluster, h high blowing fforce M Many blowoff, cleaning, cooling and drying co aapplications require hi h force f d extensive t high and reach. EXAIR’s Super Air Nozzle Clusters deliver up to 9.8 lbs of force. Three sizes for handheld and stationary mounting are available. www.exair.com/45/blast.htm U Unique flat nozzle u uses patented te technology Th 2” Super Air Nozzle The is a highly efficient, unique flat air nozzle. un Using EXAIR’s pate patented technology, a precise amount of air is released through the thin slot, across a flat surface. The result is a wide, forceful stream of high velocity, laminar airflow. Force and flow can be easily adjusted. www.exair.com/45/2san.htm Directed blast of air D EX Air Jets utilize the EXAIR Co Coanda effect (wall attachm ment of a high velocity fluid) u to produce a vacuum on one end that pulls large volumes of room ro air through the unit. Both the outlet and inlet can be ducted for remote positioning. www.exair.com/45/jet.htm Super Air Nozzles™ S The aerodynamic design of Th EX EXAIR’s Super Air Nozzles pr provide a high thrust, co concentrated stream of high ve velocity airflow. The sound lev level is as low as 71 dBA w with hard-hitting force up to 23 pounds. All meet OSHA noise i and d pressure requirements. www.exair.com/45/super.htm A breeze to a blast These Safety Air Nozzles are adjustable, making them suitable for a wide variety of blowoff applications. EXAIR’s design allows you to “tune in” the force and flow to the application requirements, thereby minimizing air consumption. A micrometer like dial indicates the gap setting. www.exair.com/45/adjust.htm This small Super Air Nozzle costs only $32. Installing it in place of one 1/4” copper tube can save you $592.80 per year. Here’s how: A 1/4" copper tube is a common homemade blowoff that hat consumes 33 SCFM when at a normal supply pressure of 80 PSIG. G. EXAIR’s award d winning Model 1100 Super Air Nozzle is 1/4 NPT and consumes only 14 SCFM at 80 PSIG. 33 SCFM (copper tube) - 14 SCFM (Super Air Nozzle) e) = 19 SCFM compressed air saved. For this example, the blowoff is continuous. Most large plants know their cost per 1,000 standard cubic feet of compressed air. If you don’t know your actual cost per 1,000 SCF, 25¢ is a reasonable nable average to use. SCFM saved x 60 minutes x cost/1,000 SCF = Dollars saved per hour. In this case, 19 SCFM x 60 minutes x .25/1,000 = 28.5 cents per hour. 28.5 cents per hour x 40 hour work week = $11.40 per week. $11.40 per week x 52 weeks = $592.80 per year. The Super Air Nozzle pays for itself in just over two weeks. For more information, visit www.exair.com/45/410.htm If you would like to discuss an application, contact an Application Engineer at: 11510 Goldcoast Drive, Cincinnati, OH 45249-1621 (800) 903-9247 . fax (513) 671-3363 RS# 104 @exair What’s new 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. Zero-backlash belt drives EDITOR’S WEB PICKS An engineer from Bell-Everman discusses backlash, stiffness, and lost motion, and explains how servobelt drives ensure precise linear and rotary positioning. View the session at www. engineeringtv.com/video/ServoBelt-RotaryPrecision-Posi;MDM-2012. 6 Finding MIMO eBooks for tablets Agilent helps explain the intricacies of MIMO (multiple-input, multiple output) technology for wireless devices. New application notes and a selection guide, plus hard copies of posters, CDs, and other resources are available at www.agilent.com/find/ MIMO-Forward. Wago’s many eBooks on electrical connectors, terminal blocks, I/O systems and networks, as well as catalogs and brochures, are now compatible with E-Book Systems’ free iFlipViewer Application for iPad and Android tablets. For additional information, visit www.wago.us. Braking technology Web site Automation product catalog Twiflex has launched a new Web site (www.Twiflex.com) on its line of industrial disc brakes, centrifugal clutch couplings, and flexible couplings and shafts. It discusses specific product features and benefits and contains application 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 a copy at www. bannerengineering.com. MySeal App Gearbox configuration tool The Freudenberg Sealing Technologies MySeal app lets engineers access a database of seal materials and evaluate the best one for a specific job. Info includes material properties, specifications, and acceptable temperature ranges, and it can suggest alternative materials. The free app for Android and Apple devices can be downloaded from iTunes, the Apple app 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 EARN CEU CREDITS WITH ONLINE PLC TRAINING COURSE Learn the basics of programmable logic controllers and receive 3 hr of continuing education credits. This continuing education course is an online curriculum with over 75 online-study videos, each lasting an average of 6 min. The course includes quizzes, progress testing, plus a final comprehensive exam. You will interact with an instructor by creating and uploading ladder programs to be evaluated and approved to ensure mastery in each section. The course uses the Click PLC as the basis for topics such as sensors, inputs, outputs, programming instructions and more. (PLC hardware is not a requirement of the course.) Use the free programming software to create programs; upload the assignments and we will test them on our trainer. You are allowed 120 days to complete the course of study. Upon satisfactory completion, you will receive 3 hr of continuing education credits. The course cost is $195.00 for a limited time. For complete information, visit www.interconnectingautomation. com and click on the “Online Training” link. Easily navigate to your perfect O-ring solution. O-Ring Gland Calculator O-Ring Size Search Seal Design Guide Material Selection Chemical Compatibility Guide Guide Engineering Request Request for Quote Find the right sealing solution faster and easier with all-new, interactive tools at applerubber.com Everything you need to guide you to your sealing destination is now only a click away. 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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 one of its few bright spots: The productivity of U. S. manufacturing workers has been rising.  In 2010, for example, the U. S. Bureau of Economic Analysis says manufacturing output per worker rose to almost $149,000 from $135,000/worker the year before, a rise of over 10%.  That was the largest annual increase in U. S. manufacturingworker productivity since the 1940s and followed a 7.85% increase in 2009. You would expect rising productivity in manufacturing to make the U. S. a more-competitive place to produce goods. And there are certainly reports in the media that some manufacturing work, indeed, is being reshored. But foreign manufacturers have not exactly been beating a path to U. S. doors, despite initiatives by politicians to promote a U. S. manufacturing renaissance. There is a good reason our manufacturing base isn’t growing like spring weeds, claims Frank Berlage, CEO of Multilateral Partners Global Advisory Group LLC, an investment firm. In a nutshell, Berlage says there is a problem with the BEA productivity figures. Better manufacturing productivity would be good if it was due to factors such as more automation or smarter workers. But that isn’t the case. MPGAG’s own research shows that 62% of the rise in productivity in U. S. manufacturing between 1995 and 2011 came from the fact that it was highly profitable for U. S.based factories to assemble components made overseas into finished goods. This is a far different situation than if the economy hosted an integrated manufacturing infrastructure that produced components and subassemblies, as well as finished goods. As such, says Berlage, the productivity gains portrayed by official figures are false. Evidence of the problem, says Berlage, can be seen in the accumulated U. S. current accounts deficit. A country’s current account is its exports minus imports. A current account deficit means a country imports more than it exports. All things being equal, one would expect a country that was getting better at making goods to import less and export more. That hasn’t happened. BEA data shows an increasing deficit in U. S. international transactions since 2010, after imports dropped during the time of the worldwide financial crisis. The difficulty with productivity arising from importation of basic components is that it could evaporate if the value of the U. S. dollar drops significantly versus that of other currencies. And this could happen sooner rather than later if U. S. debt continues to mushroom to a point where other countries are no longer interested in financing it. Nevertheless, the U. S. has plenty of room to boost its production capacity. Today, both Germany and Japan get over 20% of their gross domestic product from manufacturing. In China, the figure is closer to 40%. But only about 10% of U. S. GDP comes from manufacturing. As Berlage puts it, “If the future of the U. S. now depends on my travel agent calling my tennis coach so together they can open a nail salon, we are in serious trouble.” — Leland Teschler, Editor RS# 107 APRIL 5, 2012 4ALKABOUTABUNDLE OFADVANTAGES
 s%# TECHNOLOGY FROM EBM PAPST GIVESYOUMORECONTROLOPTIONS FOR ADVANCED APPLICATIONS THAN !# TECHNOLOGY AND ITS HIGH EFlCIENCY ALSO SAVES A WHOLE LOT OF ENERGY s&URTHERMOREIT PROLONGSTHESERVICELIFE OFAIR CONDITIONINGAND REFRIGERATIONSYSTEMSAND MAKESTHEIROPERATIONMUCH QUIETER s4HEELECTRONICSARECOMPLETELYINTEGRATEDINTO THEMOTORMAKINGTHESETRULYhPLUGANDBLOWvFANS s/NEMORETHINGOUR%#TECHNOLOGYENABLESYOUTOCREATEANENERGY SAVING BUNDLEOFSEVERALHUNDREDFANSANDCONTROLTHEMFROMASINGLEWORKSTATION &ORAWHOLEBUNDLEOFINFORMATIONVISIT www.ebmpapst.us/hyblade The engineer’s choice RS# 108 EDITORIAL STAFF EDITOR Leland E. Teschler [email protected] MANAGING EDITOR 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# 109 INDUSTRY COVERAGE 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 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 of vane pumps are built to outperform and outlast sensitive piston pumps in the most challenging situations. Our patented Walking Ring and Hydrodynamic Journal Bearings maximize your pump life for the lowest cost of ownership. With Direct Spring-to-Load Sensing and Torque Limiting Control, our vane pumps deliver the control your operation demands. The Pressure Balanced Thrust Plates improve pump efficiencies, and the variable volume and pressure compensated construction simplifies circuit design, while reducing heat and noise to make even harsh work environments less harsh. RS# 111 PUMPS VALVES POWER UNITS 952. 895. 6400 | www.continentalhydraulics.com LETTERS Union? No thanks. I’d like to answer the question posed by Stephen Mraz’s commentary (“Time for engineers to think about unionizing?” Jan. 19). If one is a professional engineer, with independent, primary adherence to professional ethics, the idea of having one’s professional standing collectively bargained should be anathema. On the other hand, if one is a laborer, albeit skilled, working at the behest of one’s employer, then subsuming one’s working conditions to the interests of union negotiators may be desirable. Just don’t confuse the two different situations, as Mr. Mraz does; one is a professional and the other a laborer. William F. Hammett Stephen Mraz’s commentary encouraging engineers to unionize is disgusting and despicable. If he thinks unions are good for Boeing, he must be completely disconnected from reality. Does he think all our good heavy-industry jobs are leaving America just because of cheaper labor offshore? Doesn’t he realize that these jobs are being driven offshore by unrelenting union demands on management? Unions and their often inefficient and crushing work rules forced U. S. Steel to close its huge Fairless works in Pennsylvania, Bethlehem Steel likewise. It is totally irresponsible for you to let this Mraz guy promote unions in your magazine. Any engineer worth his salt would be embarrassed to admit he was jealous of union members. Chris Page If you read the commentary, you will see I do not advocate that engineers join or form unions. I merely ask openmindedly why they haven’t. And to get some background, I talked to engineers in a union, SPEEA, to get their take on whether being in a union had been a positive or negative in their careers. I assume from this letter and several others that the reason the writers shun unions is that they see unions as being for the hoi polloi, the “laborers,” 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 ESIGN , “Time for engineers to think about unionizing,” was amazing. Should we really encourage engineers to jack up their companies’ cost to run a business in America? Brilliant. That’s just what we need, more U. S. companies with noncompetitive labor rates. You are setting American engineers up for layoffs and plant closings. I assume you have a union connection driving your actions. Kevin Ewing Your assumption is wrong — Stephen J. Mraz In your commentary about engineers unionizing, you lay out exactly why unionizing is a bad idea. It is called greed. Even if the company is having economic problems and nonunionized workers have to make concessions to keep the company 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. For years, the auto companies had their hands tied in dealing with labor issues, so whenever they were in trouble, they took it out on the suppliers. It seems that the only place where unions are flourishing is in the public sector where elected officials sign the contracts and taxpayers foot the bill. The disconnect allows unions to flourish at the expense of the community. Tom Van Loon Looking for American workers I just read Leslie’s Gordon’s blog (“Why does the U. S. lack skilled workers?”) and have to admit this issue is dear to my heart and I am involved in various programs to promote manufacturing jobs to high schools as well as technical schools. My daughter, a high-school senior, recently invited me to a school meeting on the various opportunities that seniors might be interested in. The presenters spoke almost totally about college opportunities; some mentioned military careers. Then was a question-and-answer session during which I asked why manufacturing jobs were not mentioned. I also briefly described how many jobs were sitting empty in my home state. All the Tools you Need for Embedded Measurements and Control, in one rugged box. Q Graphical Software Q Custom Triggering Q Sensor Connectivity Q Actuator Connectivity Q Signal Analysis Q Embedded Storage Q Control Algorithms Q Industrial Networks Q Custom Timing Q Expansion Systems The NI CompactRIO hardware platform can handle your embedded measurement and control applications, and do it in a way that outperforms other off-the-shelf systems so you don’t have to spend time developing a custom solution. The range of high-quality measurements, coupled with an extremely rugged design and the ability to modify the hardware using NI LabVIEW system design software, gives you all the benefits of customization with the convenience of an off-the-shelf platform. >> To learn more about CompactRIO, visit ni.com/compactRIO 800 891 2755 RS# 112 ©2012 National Instruments. All rights reserved. CompactRIO, LabVIEW, National Instruments, NI, and ni.com are trademarks of National Instruments. Other product and company names listed are trademarks or trade names of their respective companies. 05312 LETTERS After the meeting was over, I spoke with the presenters and discovered that the states track the number of kids the high school sends off to college. The high school is in fact graded on this metric. I then asked if high schools track the college completion rate and was told that they did not. Wouldn’t it be nice if the states credited high schools for promoting manufacturing jobs. And why not be honest on how many kids actually make it through college and earn a degree. Rich Kime As a sometime-designer of factory equipment, I can testify that many in the lower-paid echelon of factory workers are woefully underprepared to think critically, thus the heavy emphasis on “poke-yoke” design. (The original Japanese phrase translated roughly as “mistake proofing.”) One of the problems, however, is not so much that U. S. factories can’t hire well-qualified people, but that management just won’t pay reasonable wages for them and the work is uninteresting and tedious. Why should intelligent people take repetitive, nonchallenging, and poorly paid jobs in a factory when they can do more interesting things, even at low pay? Foreign workers are often less picky, even if no better qualified. If factory jobs were made more rewarding by placing more emphasis on intelligent decision making, I believe many “poorly qualified people” would end up significantly more qualified after some period of adjustment and a little training. It seems the lessons Harley Davidson learned in the late 70s 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 find ways to get employees involved in making products better. A few companies make half-hearted stabs at it, but they are really not interested in or willing to invest part of upper managements’ and shareholders’ profits to make meaningful changes. Company managers are also unwilling to delegate any part of the decision making to their employees as Harley Davidson did. Consequently we coddle and tolerate intellectual laziness, and it shows. In short, the problem is as much about poorly educated managers and greedy corporate bigwigs as it is about poorly educated and intellectually lazy laborers. Mark Stapleton Medical equipment requires high performance motors. Moog Silencer™ series brushless DC ŵŽƚŽƌƐŽīĞƌƵŶŝƋƵĞĚĞƐŝŐŶƐƚŚĂƚĚĞůŝǀĞƌƌĞƐƵůƚƐhůƚƌĂƋƵŝĞƚĨƵŶĐƟŽŶĂůŝƚLJƐŵŽŽƚŚŽƉĞƌĂƟŽŶ ĂƚǀĂƌŝŽƵƐƐƉĞĞĚƐĂŶĚƚŚĞĂĚǀĂŶƚĂŐĞŽĨŚŝŐŚƚŽƌƋƵĞĂƚĂůŽǁĐŽƐƚ >ĞĂƌŶŵŽƌĞĂďŽƵƚDŽŽŐƐƐŽůƵƟŽŶƐĨŽƌportable oxygen concentrators and other medical ĚĞǀŝĐĞƐ^ƚĂŶĚĂƌĚĂŶĚĐƵƐƚŽŵŵŽƚŽƌŵŽĚĞůƐĂƌĞĂǀĂŝůĂďůĞǁŝƚŚŽƉƟŽŶƐŽŶƚĂĐƚƵƐƚŽĚŝƐĐƵƐƐ Brushless DC Motor Features: LJŽƵƌĂƉƉůŝĐĂƟŽŶ  >ŽǁŶŽŝƐĞůŽǁǀŝďƌĂƟŽŶ  ŽŵƉĂĐƚƐŝnjĞ Looking for more?  ,ŝŐŚƌĞůŝĂďŝůŝƚLJ ^ĐĂŶƚŽǀŝĞǁŵŽƚŽƌƐƉĞĐŝĮĐĂƟŽŶƐ  >ŽŶŐůŝĨĞ  ,ŝŐŚĞĸĐŝĞŶĐLJ DŽƟŽŶdĞĐŚŶŽůŽŐLJ#&ŝďĞƌKƉƟĐƐ#ůĞĐƚƌŽŶŝĐ^LJƐƚĞŵƐ нϭϱϰϬϱϱϮϯϬϭϭဒϬϬϯϯϲϮϭϭϮ;h^3ŵĐŐΛŵŽŽŐĐŽŵ www.moog.com/components RS# 114 SCANNING FOR IDEAS Edited by Stephen J. Mraz Self-compensating miniature shocks Rod bearing is maintenancefree and selflubricating Stainless-steel outer body Available with special oils for food-industry applications O-ring Piston rod Diaphragm locator Pressure chamber with metering orifices Stainless-steel locking nut Rolling diaphragm seal made of EPDM Piston with built-in positive The MC 150 to stop MC 600-V4A Series of shock absorbers from Ace Controls Inc., Farmington Hills, Mich. (www.acecontrols.com), have outer bodies, hardened piston rods, and all accessories made of V4A stainless steel. This makes them well suited for when cleanliness is paramount or water is prevalent — such as medical technology, food handling, packaging applications, and semiconductor and electronics manufacturing. A PTFE Teflon protective cap hermetically seals the complete damping mechanism against environmental elements. The wide range of models handles loads from 2 to 10,000 lb and absorbs from 175 to 1,200 in.-lb/cycle. They operate in temperatures from 32 to 150°F and can be mounted in any position. RS# 401 16 MACHINE DESIGN.com APRIL 5, 2012 Internal hex socket For another article on clever shock absorbers scan this code or go to: http://machinedesign.com/ article/shock-absorbersfor-glass-moldingmachines-1103 COMPLETE ENGINEERING
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" HOW MAY WE HELP YOU TODAY? TECHNICAL SUPPORT: 1.877.736.4835 COMMUNITY: element14.com WEBSITE: newark.com LEARN MORE: newark.com/together RS# 115