Homemade- The future of Functional Rapid Prototyping - 2005

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versity, in Ithaca, N.Y., my group in the Cornell ComputationalSynthesis Laboratory has taken the first steps toward what we hopewill be a significant milestone: the creation of a fabricating systemthat can produce small, simple robots incorporating a battery, actu-ators, and sensors. Our goal is to one day see little automatons wrig-gle, completely finished, out of our apparatus, their electronic andmechanical subsystems having been created in one seamless process—batteries included. In the meantime, we recently succeeded in cre-ating a small fabber that we used to make a coin-shaped battery andan actuator suitable for our envisioned robot.

Compact and yet capable fabbers point the way toward a futurewhere the term “online shopping” takes on a whole new mean-ing. Imagine purchasing a piece of software that encodes detailedspecifications of something and then seeing that object emergefrom a box on your desk no bigger than a microwave oven. Likeyour desktop printer today, this desktop fabber would use somesort of cartridges. And just as desktop-printer cartridges con-

ALTHOUGH IT SOUNDS FARFETCHED,home fabbing has a precursor in

the array of rapid-prototyping systems now used routinely in vari-PAGE: CHRIS LOCKWOOD BRYAN CHRISTIE

Not every consumer product is suitable for fabbing, of course,but anything whose materials cost is low compared with its intel-lectual investment is a contender. A few examples are electric tooth-brushes, cellphones, eyewear, toys, costume jewelry, and otherdecorative items [see sidebar, “Download Museum Pieces Today”].Although many technical hurdles must be cleared before homefabbing can become a reality, it’s already possible to see its hugeimplications for engineers, designers, and distributors. Manu-facturing, at least for things that could be fabbed, would be divorcedfrom rigid corporate control, spawning new classes of independ-ent designers. Much of the stock and delivery costs associated withconventional manufacturing would be eliminated. And with appro-priate software, a product could be customized, enabling a systemof bespoke production almost inconceivable today.

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tronic components (such as resistors) with mechanical ones (suchas ball joints). The electronics-oriented systems fall under thecategory of direct-write electronics; the mechanical ones are calledsolid-freeform fabricators and can make objects of any shape.During the past 30 years solid-freeform prototyping has maturedinto a multibillion-dollar industry.

Rapid-prototyping systems, both electric and mechanical,work by incrementally and selectively depositing material froma source onto a substrate. The machines read data describingslices of a computer model and, using one of several methods,lay down successive thin layers of liquid or powdered polymers,ceramics, or metals.

The solid-freeform systems are commonplace tools for indus-trial designers. They are used mostly by automakers to create pro-totypes of car parts, from engine blocks to side-view mirrors; byappliance manufacturers to model products such as air conditionersand microwave ovens; and by consumer electronics companies tocursors, cross-linkers, binders, solvents, dispersants, and surfac-tants, whose properties—including viscosity, density, meltingpoint, and surface tension—are tailored to particular applications. Currently, rapid prototypers can fashion plastics, ceramics, andcertain metals into almost any kind of mechanical structure, includ-ing sliding and rotary kinematic joints, links, springs, gears, ratchets,nuts, and bolts, with quality good enough for functional testing.Many solid prototypes incorporate a tough, rigid plastic, calledacrylonitrile-butadiene-styrene (ABS). Electronics maker LogitechInc., in Fremont, Calif., used a solid-freeform machine fromStratasys Inc., in Eden Prairie, Minn., to make an ABS prototypeof its Bluetooth headset and then attached weights to the boommicrophone to test the design for strength. Another Stratasyscustomer, Diebold Inc., in North Canton, Ohio, builds automatedteller machine prototypes made of ABS or polycarbonate and teststheir endurance in rain, sleet, snow, and extreme temperatures.Grotell Design Inc., in New York City, makes prototypes of all its

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For electrical engineers, direct-write methods for creating elec-tronic prototypes have progressed from their origins as simple plot-ters for electronic circuits to an emerging family of commercialmachines. The new machines, which can deposit a variety of mate-rials over different surfaces according to a software design, are usedmostly for printed-circuit board models. With inkjet, plasma, thermalspray, pen, and laser-based methods, they lay down lines rangingin width from nanometers to centimeters. The prototypes are madefrom metals, ceramics, ferrites, semiconductors, and polymers, aswell as various composite materials such as polymer ceramicsfor resistors and similar components. The techniques work at lowtemperatures and can write lines at speeds approaching one meterper second [see sidebar, “Technologies for Future Fabbers”].

Today’s most advanced direct-write techniques work not onlyon flat boards but also on nonplanar substrates, flexible plasticsubstrates, and even textiles to make flexible and compact circuitsthat conform to the tight space requirements of certain consumerproducts. Because direct write lends itself not only to prototypingbut also to small-scale production of specialty parts and devices,the U.S. Defense Advanced Research Projects Agency has pouredmillions of dollars into the technologies’ development. DARPA isfunding a project by Potomac Photonics Inc., in Lanham, Md., todevelop and commercialize laser-based direct-write tools that candeposit metal, dielectric, and ferrite materials …… 此处隐藏：20090字，全部文档内容请下载后查看。喜欢就下载吧 ……