Tài liệu Machine design, tập 84, số 16, 2012

October 18, 2012 A Penton Media Publication Tune in to EngineeringTV.com Special issue on MOTION CONTROL A Robot Revolution page 20 OFF TILT: WHERE INDUSTRIAL MEMS GYROSCOPES EXCEL, page 34 SIMULATION HELPS CALCULATE TRAJECTORIES, page 40 PROTOTYPING WITH SPRINGS, page 44 CLOUDBASED HELP FOR MOTION SYSTEM DESIGNERS, page 50 [ MOTOR TRUTH #7 ] Can I save energy by using a VFD (inverter)? YES NO MAYBE The truth is that it depends on your application. If you have a high-cycling application, a VFD can reduce the starting current on each cycle. If you have a hoisting application, a VFD can provide energy regeneration. If you have an oversized motor on a small load, a VFD with flux control can maximize the motor efficiency. Otherwise, a VFD is a load and actually consumes energy - especially if you use a high carrier frequency. Visit sewmotortruth.com/truth7 to get the whole story on VFDs and energy-efficient drivetrains. sewmotortruth.com/truth7 864-439-7537 RS# 101 www.theleeco.com Go ahead, push us to your limits. RS# 102 We love a good challenge. If you need a fluid handling component for whatever reason, no matter how extreme, talk to The Lee Company. We’ve been solving complex fluid control problems in all kinds of industries for more than 60 years. Our extensive family of precision fluid control products offers unsurpassed reliability in just about every configuration you could imagine, including: • Miniature Solenoid Valves • Fixed and Variable Volume Pumps • Atomizing and Dispense Nozzles We’re not just talking about off-the-shelf solutions, either. A Lee engineer will be happy to discuss your application, and develop a custom design if needed. From managing nanoliter droplets to creating fully integrated fluidic systems, we’re unsurpassed in breadth and experience to deliver the precise, reliable performance you require. Whatever problem you face, make the solution easy. Contact The Lee Company today. Innovation in Miniature • Micro Dispensing Valves • Integrated Fluidic Manifolds • Custom Engineered Designs See us at MD&M Minneapolis, Booth #636 The Lee Company 2 Pettipaug Road | Westbrook, CT 06498-0424 Tel: 860-399-6281 | 800-533-7584 | www.theleeco.com Westbrook • London • Par is • Fr ankfur t • Milan • Stockholm VOLUME 84 ISSUE 16 OCTOBER 18, 2012 CAE CAE Building a BETTER SPACECRAFT FEATURES CAE software tests hypersonic-reentryvehicle designs The European Space Agency launch of Thales Alenia Space’s Intermediate eXperimental Vehicle aboard the Vega small launch vehicle is planned for 2013. Authored by: Kyle Indermuehle Aerospace Lead Simulia Providence, R. I robot for the rest of us 20 AA relatively low-cost factory-floor robot that can be trained or programmed by a factory-floor worker. Edited by Leslie Gordon [email protected] Key points: • Process-automation software can link design and simulation models to automate the execution of hundreds or even thousands of simulations. • The software can help designers improve designs by improving them in terms of performance or cost variables through statistical methods. Resources: Simulia, www.simulia.com For more on simulation software, scan this code or go to: http://machinedesign.com/ article/software-automates-the-executionof-thousands-of-simulations-0609 40 MACHINE DESIGN.com As CAE software becomes increasingly sophisticated, engineers can now refine designs to their nearly final form. This lets engineers test physical prototypes later in the product-development cycle. The use of CAE software is critical in the space industry, where it’s difficult to create test settings that simulate real-world conditions. Vacuum chambers and wind tunnels help, but they cannot account for all conditions at the same time. That’s why spacecraft producer Thales Alenia Space Italia (TAS-I) in Italy used CAE software in the design, testing, and building of its hypersonic reentry vehicles for the European Space Agency. Head of aeromechanics and propulsion at TAS-I, Cosimo Chiarelli helped design and test the vehicles. He explains that the physics of atmospheric reentry are complex, so vehicle analysis required a multidisciplinary optimization (MDO) approach to account for all the variables. Variables include aspects of the spacecraft structure such as geometry (length and shape), as well as the di- mensions and material attributes of the shell and thermal-protection system. Other variables include the trajectory (comprising the vehicle’s speed, altitude, and angle of attack), the thermal conditions for the vehicle’s windward, leeward, and nose zones, and the thermal loads the vehicle encounters. The final design accounts for all variables, with a focus on the 150 sec that make up the most-critical portion of reentry. To improve designs, engineers conducted separate simulations for each of the physics disciplines. They used a collection of software packages and divided the analysis into seven major computational tasks and 40 subtasks, many with their own input and output file types. Engineers used Isight process automation software from Simulia, Providence, R. I., to organize the tasks, manage the execution of TAS-I’s dif- OCTOBER 18, 2012 The MDO workflow for the reentry vehicle in Isight comprised several analysis tasks such as grid generation and trajectory computations. It used a variety of commercial and proprietary codes and input and output file types. Engineers used the software to tie together separate simulations and automate the analysis. OCTOBER 18, 2012  40 aim with MEMS gyros 34 Taking Superaccurate MEMS gyroscopes ferent codes, and aide in the understanding of results from all of the tasks. “The software helped us create flexible simulation workflows and automate the exploration of solutions for the large design matrix,” says Chiarelli.” To conduct a feasibility study of their new MDO approach, engineers chose a theoretical hypersonic reentry vehicle and applied simplified assumptions. Further streamlining the process, they decided to optimize globally for all variables combined, rather than locally for each individual variable. To minimize costs, engineers applied the process-automation software’s adaptive simulated annealing algorithm, a statistical technique that searches the envelope of design solutions. Isight performed 200 iteration cycles in only a day, assembling several designs that satisfied requirements. simplify the motion-sensing tasks of industrial robotics. a better spacecraft 40 Building CAE software tests hypersonic- MECHANICAL Working reentry-vehicle designs. Here are some tips when using springs for prototyping and design. with STOCK SPRINGS 44 Here are some tips when using springs Working with stock springs Mechanical equipment and related hardware routinely include springs in their designs. And in a perfect world, knowing the load and travel, an engineer can adjust the mating parts so that the design can use a stock spring. However, that is usually not the case, and springs are frequently an afterthought. Often this is because springs are well-engineered and for prototyping and design. design gets 50 Motion help from the cloud proven components. Springs operating within their design parameters will last a long time. And they come in thousands of different sizes and versions. Most common are compression and extension springs, made from various materials, with or without a finish. Stock springs are often used for applications requiring less than 500 springs per year. Generally, however, it is not only better but more cost effective to contact spring manufacturers with specific requirements. From there, the manufacturer may recommend a new design and make a customized spring for little or no cost premium. One cannot emphasize enough the importance of discussing design requirements with a spring manufacturer. Stock springs are great for prototyping, but their use in production often compromises other aspects of a design. This article is meant to help size springs for prototyping, prior to seek-  Authored by: Norman Ellis Ellis & Associates Laguna Hills, Calif. Edited by Kenneth J. Korane [email protected] Key points: Free and simple cloud-based analytic tools help designers quickly analyze motion-system performance in both the time and frequency domains. • Stock springs are generally intended for prototyping, and their use in production can compromise designs. • Experts recommend discussing specific design requirements with a spring manufacturer. Stock springs are useful for prototyping, but altering mating parts to accommodate a stock spring can compromise other aspects of the final design. 44 MACHINE DESIGN.com Resources: Spring Manufacturers Institute, www. smihq.org. The SMI is a good source for information on spring design and capabilities, as well as for locating spring manufacturers. OCTOBER 18, 2012 44 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 OCTOBER 18, 2012 MACHINE DESIGN.com 41         We’ve got the pneumatic parts you need, and they ship the same day.* New air pilot valves are a basic component of many pneumatic systems; our AVS-5 series can be used individually, or multiple valves can be assembled on manifolds available in up to 8 stations. Manual control valves are designed for non-electrical operator control applications. These basic valves are available in toggle hand lever, push-pull, and rotary hand lever styles, as well as foot pedal valves. Air Pilot Valves - start at: $14.00 • • • Body ported five-port (four-way) spool valves 1/8” to 1/2” NPT port sizes Single or double pilot operation Manual Control Valves - start at: $14.00 • • • Toggle hand lever and push-pull styles with body ported five-port spool valves, in 1/8” and 1/4” NPT port sizes 4-port rotary valve stye in 1/4” and 1/2” NPT port sizes Foot pedal valves with guard are 5-port spool valves with 1/4” NPT ports, momentary or latching models Solenoid Valve Cables & Air Valve Connectors See everything at: - start at: $4.75 www.automationdirect.com/pneumatic-parts • • • Also Available 8, 10 and 18mm (pin spacing) DIN 43650 form cables; 9.4 and 11mm DIN style cables 24, 110 and 230 VAC/DC models available PVC jacketed cables in 1, 3 or 5 meter lengths Brass Threaded Fittings - start at: $4.00 (5-pack) • • • • Tubing and Hose 10 different styles, including Tee and elbow Male and female connectors in 1/8” to 1/2” NPT sizes Work with water, oil, air and other gases Maximum pressure 800 psi Quick-disconnect Air Couplings - start at: $5.00 Pneumatic Air Cylinders Fittings and Air Couplings • • • Plugs and couplers for 1/4” and 3/8” inch hose sizes Male and female NPT threaded Compatible with three of the most popular connection styles www.automationdirect.com Pneumatic Solenoid Valves and Manifolds Air Preparation Go online or call to get complete information, request your free catalog, or place an order. 1-800-633-0405 RS# 103 ON THE COVER Baxter, a robot from Rethink Robotics. DEPARTMENTS 8 EDITORIAL Antidote to innovation … Six Sigma 10 EDITORIAL STAFF 12 LETTERS 16 SCANNING FOR IDEAS Going big with ultrasmall ball screw Rotary motion with speed and precision 20 REPORTER’S NOTEBOOK 24 LOOKING BACK 31 COMMENTARY So much for the idea of putting a hex on your boss — Stephen J. Mraz 33 INDUSTRIAL DESIGN Making “cheap” products look expensive 63 ORR ON ENGINEERING What’s New? 64 SOFTWARE PRODUCTS 66 PRODUCT SPOTLIGHT Hydraulic & pneumatic cylinders 68 74 76 77 78 78 79 4 PRODUCTS DATA FILES BUSINESS INDEX AD 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. OCTOBER 18, 2012 POSTMASTER: Send change of address notice to Customer Service, MACHINE DESIGN, P.O. Box 2100, Skokie, IL 60076-7800. Secure your operations with proactive maintenance Imagine the conditions in the North Sea. They take their toll on all types of equipment. Bearings are no exception. At one of the major production platforms, failing motor bearings used to cause gas compressors to break down as often as every third month. Each time, that meant 25% lost production for several days. Jim Marnoch and his team provided SKF ProActive Reliability Maintenance services. After thorough analysis of the vibration signatures and the damaged bearings, they found a long term solution. SKF NoWear bearings along with a new sealing arrangement made all the difference, allowing the compressors to run 6 times longer than before. At today’s high oil prices, for every breakdown that can be avoided, the platform operator saves tens of million dollars. On top of that, these improvements also reduce health, safety and environmental risks. It’s another great example of knowledge engineering at work. Find out more at www.skf.com/poke The Power of Knowledge Engineering Gas Export Compressor SKF ProActive Reliability Maintenance ® NOWEAR is a registered trademark of the SKF Group. Jim Marnoch, SKF RS# 104 What’s new online machinedesign.com Free Webcasts: Designing Effective Safeguarding for Machines Thursday, October 18, 2:00 p. m. ET Attend this Webinar to learn how to design effective machine safeguarding. Experts from Schmersal will discuss types of hazards, various options for separating guards and devices, different levels of circuit design, and how to engineer a complete safety system. Making 3D Printed Parts “Real” Thursday, October 25, 2:00 p. m. ET Rapid prototyping — now called additive manufacturing — has had a profound impact on the product design/development process across many industries. This presentation from GreatBatch Medical and Objet will explore recent advances and benefits of AM, including: • Materials that range from rigid to flexible, high temperature, and clear. • Time and cost savings using Polyjet technology. • Example applications. • A Q&A on equipment and capabilities. Learn more and register for these events at http://machinedesign.com/training. Environmentally safe cryogenic machining EDITOR’S WEB PICKS The chief technical officer of MAG IAS explains the benefits of using cryogenic machining on composites and ultrahard metals, and how environmentally safe cooling fluids eliminate waste-disposal problems manufacturers face with traditional coolants. View it at www.engineeringtv. com/video/Cryogenic-Machining-UsingEnvir;International-Manufacturing-Tec. 6 RS# 105 MACHINE DESIGN.com OCTOBER 18, 2012 Actuators and drives App Bosch Rexroth’s GoTo Products apps for iPhone and iPad provide quick access to information on more than 3,500 linear motion, hydraulic, pneumatic, electric drive, and control products. Content includes technical data, dimension and specification tables, and product visuals, as well as video clips explaining key features of various motion and control technologies. The iPhone version takes advantage of GPS and autodial features to simplify ordering from the nearest distributor. Learn more at www. boschrexroth-us.com/gotoapp. Simulation Hall of Fame Do you consider your simulations prize-worthy? The Ansys Hall of Fame competition showcases eye-popping simulation images and striking videos that illustrate real-world multiphysics applications using the company’s software. Winners will be selected based on the project and resulting benefits, with Apple iPads as the top three prizes. Deadline is November 23. Learn more and view previous winners at www.ansys.com. Elastomers and thermoplastics for vehicles Minnesota Rubber and Plastics has a new brochure on molded components and assemblies for motor-vehicle applications. Charts list a wide range of products, compare the performance of amorphous and semicrystalline polymers in relation to cost, and provide selection criteria for high-temperature thermoplastics. Get a copy at www. mnrubber.com. IT’S MOTION CONTROL VERSUS MOTHER NATURE ON CENTRE COURT. ©2010 Moog. All rights reserved. RS# 106 WHEN IT COMES TO HIGH PERFORMANCE MOTION CONTROL, MOOG EXPERTS ARE THERE. When design engineers sought the best way to control the new retractable roof at Wimbledon’s famed Centre Court, they turned to Moog. The result was an innovative all-electric installation that provides 148 axes of control via high performance electric actuators, servo motors, servo drives, closed-loop controls and software. Now, more than 1,100 metric tons (1,212 tons) of steel and 5,200 square meters (17,060 square feet) of fabric move swiftly and safely to prevent rain delays. Moog’s combination of motion control expertise and world-class solutions can make the difference for you too—no matter what industry you’re in. For more information call 866-580-7610. How can we improve your machine design? View our Wimbledon video at http://info.moog.com/wimbledon/1 WHAT MOVES YOUR WORLD moog.com/industrial EDITORIAL Antidote to innovation … Six Sigma Reliability in a Clutch ...a clutch, brake or power transmission part for that matter. Since 1903 Carlyle Johnson has solved some of history’s toughest motion control challenges – it’s what we love to do. Our precision electrical, mechanical, air and hydraulic power transmission products consistently prove reliable and dependable in every application. Underwater, on the ground and in the air, CJM is everywhere. Standard and Custom Clutch, Brake & Power Transmission Solutions 291 Boston Turnpike • Bolton, CT 06043 Phone: 860-643-1531 www.cjmco.com 8 RS# 107 MACHINE DESIGN.com There has been a lot of soul searching in the U. S. about a perceived lack of innovation among domestic manufacturers. One sign U. S. manufacturers have trouble innovating comes from the management consulting firm Booze & Co.’s annual report on the 1,000 companies that spend the most on research and development. Last year, only one company among the top 10 R&D spenders (Microsoft) made the list of the top-10 most innovative companies. In a nutshell, Booze points out that a lot of companies spend piles of money on R&D that don’t result in innovative products. In the quest for things to blame for this poor performance, Six Sigma programs seem to be one of the latest scapegoats. The case for Six Sigma as a cause of mediocre research is made by Navi Radjou, Jaideep Prabhu, and Simone Ahuja in a book called Jugaad Innovation, which outlines ideas for innovating more frugally. What convinced these three business consultants that Six Sigma kills the innovative spark was 3M’s experience applying Six Sigma processes to its R&D labs in the early 2000s. By 2005, 3M’s share of revenues from new products had dropped from the 30% it had seen for decades to 21%. The reason: 3M engineers became risk averse and played it safe, the consultants say. The situation turned around when 3M rolled back the program and reinstituted an old practice of giving employees 15% of the their paid work time to pursue pet projects without worrying about whether such efforts could be immediately commercialized. But Six Sigma is just a symptom of what ails R&D in most companies, the consultants insist. It is a manifestation of an approach to R&D structured so that it lacks flexibility and is insular. Companies that run R&D under rigidly structured schemes like Six Sigma seem to think that innovations can be scheduled, say the consultants. Another problem: Western companies often measure innovation the wrong way, by the number of patents they file. Big mistake, the consultants claim. The patenting process costs a lot, is time consuming, and often mires the patent holder in lawsuits. Better to not bother with patenting at all. Instead, focus on commercializing developments fast rather than trying to erect barriers around them. Maybe so, but having heard these arguments, I am convinced the real obstacle to innovation in many companies lies elsewhere: In the ranks of top management. Even when an innovative product gets developed, bottom-line oriented managers are likely to axe it before consumers can venture their opinion. That’s because ivory-tower managers often don’t know their own customers, so the only thing that can convince them an idea is good is a spreadsheet full of data. But there won’t be any such data for something that is a real innovation. (After all, the market for MP3 players was microscopic prior to Apple’s invention of the iPod.) And by the time there’s enough evidence to justify an innovative project, it may be too late to commercialize it. Radjou, Prabhu, and Ahuja seem to agree. They say top management’s overreliance on formal data shows why 90% of all consumer-product R&D goes into tweaking existing offerings, and why big R&D spenders leave the door open to competitors with truly innovative ideas. — Leland Teschler, Editor OCTOBER 18, 2012 air cylinders More Sizes • More Styles • More Accessories Performance that Engineers havee Learned to Trust. 40”  VRI     H DY  7KH\K KLSWKH 6  R W  \ 5HDG ,WHPV 35” \ D '  H 6DP 30” HDEOH J Q D K F ,QWHU 7RWDOO\ H1RZ G D U J S 8 25” 20”  15” 10” 5” 0“ For the past 50 years, Clippard has been providing quality cylinders for thousands of applications around the world. Cylinders that are responsible for millions s. Cylinders that pr rovide of production cycles. provide mance and payback. paybackk. outstanding performance 877-245-6247 www.clippard.com/cylinders the finest. fast! Cincinnati, OH RS# 108 On-li ne c make onfigurato s ord r simp ering le! EDITORIAL STAFF EDITOR Leland E. Teschler [email protected] GRAPHALLOY BEARINGS CAN TAKE THE HEAT. ® MANAGING EDITOR Kenneth J. Korane [email protected] SENIOR EDITORS HANDLE HIGH TEMPERATURE AND HARSH OPERATING CONDITIONS WITH EASE GRAPHALLOY® bushings, bearings and components: • Survive when others fail • Run hot, cold, wet or dry • Excel at -450°F to 1000°F • Corrosion resistant • Self-lubricating • Non-galling • Low maintenance • Ovens, dryers, pumps, valves, turbines, mixers, conveyors Leslie Gordon [email protected] Stephen J. Mraz [email protected] ASSOCIATE EDITORS GRAPHITE METALLIZING CORPORATION Yonkers, NY 10703 U.S.A. Lindsey Frick [email protected] Robert J. Repas, Jr. [email protected] ISO 9001:2008 H06a TEL. 914.968.8400 • WWW.GRAPHALLOY.COM/MD RS# 109 INDUSTRY COVERAGE: AUTOMOTIVE, PACKAGING, MEDICAL Stephen J. Mraz CAD/CAM, MANUFACTURING Leslie Gordon ELECTRICAL, ELECTRONICS Robert J. Repas, Jr. FASTENING & JOINING, MATERIALS Lindsey Frick FLUID POWER Kenneth J. Korane MECHANICAL Lindsey Frick Kenneth J. Korane UÊ£ääÊ`iÝiÃÊ«iÀÊÕÌiÊ UÊ*ÀiVÃÊÕÌ}Ê-ÞÃÌi UÊ´Ê°äÓ»Ê-iÀÛÊ*>V>}iÊ
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Rubenking Art Director 1300 E. 9th St. Cleveland, OH 44114-1503 10 MACHINE DESIGN.com RS# 110 OCTOBER 18, 2012 ƵƚŽŵĂƟŽŶĞƋƵŝƉŵĞŶƚƌĞƋƵŝƌĞƐŝŶŶŽǀĂƟǀĞƐŽůƵƟŽŶƐĨŽƌŵŽǀŝŶŐƉŽǁĞƌĂŶĚĚĂƚĂ ĂĐƌŽƐƐƌŽƚĂƟŶŐŝŶƚĞƌĨĂĐĞƐ"DŽŽŐŽīĞƌƐŽǀĞƌϭϬ,ϬϬϬƐůŝƉƌŝŶŐĚĞƐŝŐŶƐ"DŽĚĞůƐ ĂƌĞĂǀĂŝůĂďůĞŝŶĐĂƉƐƵůĞ,ƚŚƌŽƵŐŚďŽƌĞĂŶĚĮďĞƌŽƉƟĐĐŽŶĮŐƵƌĂƟŽŶƐ" ZĞůŝĂďŝůŝƚLJŝƐďƵŝůƚŝŶƚŽĞĂĐŚƉƌŽĚƵĐƚ"džƚĞŶƐŝǀĞůŝĨĞƚĞƐƟŶŐŵĞĂŶƐŽƵƌƐůŝƉ ƌŝŶŐƐĂƌĞĚĞƐŝŐŶĞĚĂŶĚŵĂŶƵĨĂĐƚƵƌĞĚƚŽŽīĞƌůŽŶŐůŝĨĞĂŶĚůĞƐƐĚŽǁŶƟŵĞ" >ĞĂƌŶŵŽƌĞĂďŽƵƚDŽŽŐ/ƐƐŽůƵƟŽŶƐĨŽƌĂƵƚŽŵĂƟŽŶĂŶĚƌŽďŽƟĐƐ"^ƚĂŶĚĂƌĚƐůŝƉ ƌŝŶŐĚĞƐŝŐŶƐĂƌĞƌĞĂĚLJĨŽƌƋƵŝĐŬĚĞůŝǀĞƌLJŽƌĐĂŶďĞƚĂŝůŽƌĞĚĨŽƌƵŶŝƋƵĞƉƌŽũĞĐƚƐ" ŽŶƚĂĐƚƵƐƚŽĚŝƐĐƵƐƐLJŽƵƌĂƉƉůŝĐĂƟŽŶ"   >ŽŽŬŝŶŐĨŽƌŵŽƌĞ ^ĐĂŶƚŽǀŝĞǁƐůŝƉƌŝŶŐƐƉĞĐŝĮĐĂƟŽŶƐ ^ůŝƉZŝŶŐ&ĞĂƚƵƌĞƐ 3 3 3 3 3  DŽƟŽŶdĞĐŚŶŽůŽŐLJ&ŝďĞƌKƉƟĐƐůĞĐƚƌŽŶŝĐ^LJƐƚĞŵƐ нϭϱϰϬϱϱϮϯϬϭϭဒϬϬϯϯϲϮϭϭϮ;h^ ŵĐŐΛŵŽŽŐ"ĐŽŵ ǁǁǁŵŽŽŐĐŽŵĐŽŵƉŽŶĞŶƚƐ RS# 111 ŽŶƟŶƵŽƵƐϯϲϬΣƌŽƚĂƟŽŶ ŽŵƉĂĐƚƐŝnjĞ DĂŝŶƚĞŶĂŶĐĞĨƌĞĞŽƉĞƌĂƟŽŶ ZŽďƵƐƚƉĞƌĨŽƌŵĂŶĐĞ ŽŵƉĂƟďůĞǁŝƚŚĚĂƚĂ ďƵƐƉƌŽƚŽĐŽůƐ LETTERS An engineer is an engineer . . . Having run an engineering and design business for over 40 years, I have followed with amusement t h e “C A D J o c k e y ” d i s c u s s i o n (“The Attack of the CAD Jockey?” Aug. 23). We design and build commercial products and production machinery, and I find that a person’s title or degree doesn’t matter. It is what comes out at the end of a project that’s impor tant. We let people do whatever they can and benefit from their experience. Harold Parks A good engineer must be both a good engineer and a good designer. A good designer is not an engineer (and is not expected, or required, to be one). Dayle D. Winnie Anybody can learn CAD and create geometry. But not all people can design. Designers have creativity and some sense of what will make a product work. I’ve been on all sides of this designer/ engineer debate for many years and have met many design engineers who could not design something as simple as a pin. On the other hand, I’ve worked with designers who understood basic principles and could engineer and design products. In companies, there is a mix of people. There are those who can analyze things once they are designed, those who can take something from concept all the way through manufacturing, and those who create geometry from concepts sketched out on napkins. It is not incorrect to state that design is simply creating geometry. I realize that in some places, CAD jockeys are called designers, but nothing could be further from the truth. It takes someone with engineering-design knowledge to create designs. Jaime Robledo 12 MACHINE DESIGN.com Job-title controversy Readers are still hashing out the meaning of the terms “designer” and “engineer.” And although they have no problem defining ethical behavior, they also think ethical behavior is disappearing. Over the last 25 years I have gone from a technical illustrator to an automation design engineer without an engineering degree. However, it is important to note that at some companies I would not be considered an engineer without an engineering degree. Prior to the meltdown of 2008, I was a special projects engineer at a company that was growing and letting HR control titles. As a result, HR personnel would not consider anyone without an engineering degree for any engineering positions and were forcing people with 10 to 15+ years of experience but no degree out of engineering positions. At another company, I was given the title mechanical designer because I do not have an engineering degree. Those with engineering degrees were called mechanical engineers. My experience indicates that the term “designer” has two basic definitions. The one used in the editorial refers to the person responsible for the look, touch, and feel of the product. The second is the person who does the same functions of an engineer without an engineering degree. The second definition is the one most of your readers are most familiar with. Another way to look at it is that the first definition refers to industrial design, while the second refers to me- OCTOBER 18, 2012 chanical design. As a side note, I found the definitions for “designer” frustrating during a job search. A thorough and specific list of job duties and responsibilities is much clearer than just a title with generic qualifications. By the way, I have continued my education by earning Associates degrees in technical illustration and math, a BA in Family Studies, an MBA, and a graduate degree in accounting. It would be nice if engineering classes were offered in the evenings like so many other programs. John E. Melton CAD jockeys are computer-age draftsmen and draf tswomen. They are not designers unless they have additional training in, knowledge of, and aptitude for one or more of the numerous fields of design. Even sketching or drawing free hand requires talent not necessar y for good CAD jockeys. Indeed, I am a CAD jockey and I can’t draw a pretty picture to save my life. Bob Vanstone Farewell ethics Our societ y has gone from a Christian-based one in the idealistic past to the “if it feels good do it” attitude in the 60s, to our current and cynical “get it while Sapa Introduces TM The Core of Consistency for Machine Grade Products Sapa ACC-U-LINE aluminum rod and bar products assure next-level quality in tolerances, mechanical properties, machinability and surface finish. • Tolerances for size, flatness, straightness and twist are 1/2 or better than Aluminum Association Standard Tolerances. • Faster, precision machining with a cleaner surface finish, increased scrap recovery and lower operating cost ACC-U-LINE 6061 Rod and Bar Core It’s What’s Inside That Counts! ACC-U-LINE features consistent, controlled grain structure – Sapa’s extensive use of indirect extrusion technology makes it possible. ACC-U-LINE products are produced in rod, plate, and hex, square and rectangular bar, available exclusively from Sapa Extrusions North America and its authorized Premier® Distributor Partners. For machining performance with accurate, consistent results, specify ACC-U-LINE. RS# 112 Scan for more information One Company, One Call, Unlimited Solutions 800-233-3165 l www.sapagroup.com/NA [email protected] Competitor’s Core LETTERS you can” mood today (“ Where Did Ethics Go?” Sept. 6). There is a tendency to push morals to the side when it comes to personal responsibility in society. Why are we surprised to find out it carries over into professional careers? Or, if we take the Darwinistic approach of survival of the fittest, instead of taking care of the least among us, did Madoff actually do anything wrong other than get caught? Mike Bartle Ethics went to the same place morals and principles went. Our nation has been in a state of decline for many years now as we stand idle watching entertainment, and political and other institutions raise our kids to be what we see today. This will not stop until we get off the sidelines and get involved. Thanks for your words of wisdom, I was feeling like a loner in this new world. Felix Ronmint Curing the U. S. blues More engineers, greater encouragement of the entrepreneurial spirit, and most importantly, fewer MBA’s (“Made in America?” June 14). This is what we need for manufacturing to thrive in this country. Joe Bonasses This is one of the best and most encouraging articles I have seen in a long time regarding the state of American manufacturing. We need more forward thinkers like the folks mentioned here. Buy American. Be American. Bill White RS# 113 14 MACHINE DESIGN.com OCTOBER 18, 2012 LETTERS TO THE EDITOR Please include your name, address, and daytime phone number. Letters may be edited for brevity and to focus on essential points. Mail: Letters, MACHINE DESIGN, 1300 E. 9th St., Cleveland, OH 441141503, Fax: 216-621-8469 E-mail, Editorial: [email protected] Conversion error If the Super Draco can develop 150,000 lbf of thrust, then the metric equivalent should be 670,000 N (“Spacetruckin’ with SpaceX,” Sept. 6). Dennis McKee Good catch. The correct figures for the Super Draco should be 15,000 lb of thrust or 67,000 N — Stephen J. Mraz RS# 114 SCANNING FOR IDEAS Edited by Stephen J. Mraz Going big with ultrasmall ball screw Wiper Return Screw shaft Ball bearings Engineers at Steinmeyer Inc., Burlington, Mass. (www.steinmeyer.com), recently added a new Nut device to its line of precision balls screws, the Ultraminiature, which the company claims is the “world’s smallest commercially available ball screw.” Its diameter can be as small as 3 mm and have a pitch of 1 or 0.5 mm. This makes the device well suited for medical applications such as dispensing exact amounts of liquids. The ball screw can be ordered in several sizes ranging up to 16 mm in diameter with a 30-mm pitch. The screws come with one of four types of ball nuts and with or without preload. The actuators are made of precision-ground, hardened tool steel. Stainless steel is For more information on rolled and ground ball screws, scan this an option. The screws can meet ISO code or go to: http:// tolerances from P0 to P5. machinedesign.com/ RS# 401 article/how-rolled-andground-ball-screwsstack-up-0708 r formation via ou Request free in Web site at Reader Service c design.com/rs ww w.machine 16 MACHINE DESIGN.com OCTOBER 18, 2012 N OW I T H I N K I N 3 D. AND MY DESIGNS JUST KEEP GET TING BET TER. With our Dimension® 3D Printer, I know my model will represent my idea exactly. And that makes it easier to improve my design with each iteration. Our Dimension is right here in the office, and that helps us get our products to market faster. And, with the Dimension Print TM Pack we got everything we needed to start printing immediately. The Dimension models we create are made in ABS, so they’re also tough and durable. Overall, Dimension gives me an amazing sense of freedom—and creativity. Find out more at www.dimensionprinting.com/macd4 RS# 115 ©2012 Stratasys, Inc. SCANNING FOR IDEAS Rotary motion with speed and precision Dial-plate mounting holes Gear teeth Large central opening for mounting equipment or cabling Gearbox Pinion Precision Ring Drives from the Nexen Group Inc, Vadnais Heights, Minn. (www.nexengroup.com), combine a rolling pinion with a precision-grade bearing and gearhead. There are four drives in the series with ratios ranging from 64:1 to 220:1. Peak torque goes from 563 to 1,936 Nm. And accuracy ranges from ±11 to ±35 arc-sec, with repeatabilities of ±4.2 to ±1.2 arc sec. The drives can handle peak-torque inputs at any time, which lets it index at twice the speed of traditional camdriven systems. The rolling pinion is 99% efficient, while the gearbox is 96% efficient, making the rotary device an energy saver. And the bearing-supported pinion rollers move smoothly across the face of each tooth, so it generates less noise and vibration than conventional rotary devices. The drive mounts on a table supported by cross-roller bearings rated for 1,575-kN loads. RS# 402 The new 955 eBrik linear displacement transducer. Price and performance so well balanced, it just might displace potentiometers. At last, there’s a purely electronic solution to position sensors. Our new 955 eBrik uses magnetostrictive technology so there’s no contact, no moving parts, nothing to wear out. No erratic position signals. Available in 1" to 72" stroke lengths, it’s economical and versatile enough for many applications, field-programmable, and the perfect replacement for old-style potentiometers. Learn more at our website. ametekapt.com 18 MACHINE DESIGN.com OCTOBER 18, 2012 RS# 116