3D打印逐漸發(fā)展成熟，似乎只在一夜之間，就已經(jīng)從一個(gè)打印 3D 模型組件的新奇市場變成一個(gè)制造原型的新興產(chǎn)業(yè)主力。最終，它還可能取代像射出成型或計(jì)算機(jī)數(shù)值控制(CMC)積層機(jī)械加工等制造能力，以及支持這些制造方式的全球工具供應(yīng)鏈。 目前，包括Stratasys與3D Systems等公司均提供了重要的工業(yè)級3D打印機(jī)，但卻還未能在主流工業(yè)領(lǐng)域展現(xiàn)積層制造的真正實(shí)力。因此，在日前由美國弗吉尼亞理工大學(xué)(Virginia Tech)主辦的“2014年春季積層制造挑戰(zhàn)賽”(Spring 2014 Additive Manufacturing Grand Challenge)，就成了證實(shí)這些3D打印工具能力的最佳機(jī)會。包括美國空軍科學(xué)研究院(AFOSR)、美國國防大學(xué)(NDU)、機(jī)器人研究公司 (Robotic Research LLC,)以及Stiefel家族基金會均贊助了這項(xiàng)競賽。

Virginia Tech美國弗吉尼亞理工大學(xué)主辦「2014年春季積程制造挑戰(zhàn)賽」，展示3D打印工具打造能以遙控行駛的小汽車。
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美國弗吉尼亞理工大學(xué)(Virginia Tech)主辦的2014年春季積層制造挑戰(zhàn)賽(Spring 2014 Additive Manufacturing Grand Challenge)展示實(shí)用3D打印工具，打造出可在地面行駛的汽車或空中飛行的載具。 Virginia Tech教授Christopher Williams表示：“3D打印的重點(diǎn)在于降低供應(yīng)鏈的復(fù)雜度，而不是預(yù)先制造出所有的組件，然后再輸送至世界各地進(jìn)行組裝。如今你只需要擁有一臺3D 打印機(jī)、一套電子模型套件以及打造組件所需的原始材料即可。這就是3D打印的愿景?！? “這項(xiàng)挑戰(zhàn)賽的想法是要證明如果您將 3D打印機(jī)送至比賽現(xiàn)場，你就能在幾個(gè)小時(shí)內(nèi)看到它制造出符合特定任務(wù)的汽車。目前的趨勢是制造出多功能的昂貴汽車，但透過3D打印工具，你可以打造出完 全因應(yīng)某種場合需要的低廉汽車，可在不需使用時(shí)收在架上或甚至直接丟棄，”Williams解釋。 第一屆積層制造挑戰(zhàn)賽目前只開放給Virginia Tech的學(xué)生參與，如果舉辦成功的話，未來希望能擴(kuò)大開放至每一所大學(xué)?！斑@是該領(lǐng)域的第一次競賽，”William表示，“但我們預(yù)計(jì)這項(xiàng)先驅(qū)性的競賽最快將在今秋開始也開放給其他大學(xué)共襄盛舉?！? 本文授權(quán)編譯自EE Times，版權(quán)所有，謝絕轉(zhuǎn)載 第2頁：舉辦比賽的目的，以及廠商贊助這項(xiàng)競賽的動機(jī) 第3頁：可自行選擇打印材料，以及三種3D打印機(jī)

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{pagination} 廠商贊助這項(xiàng)競賽的動機(jī)有兩方面：首先，為了證明3D積層打印不只是新奇的玩意兒，而是具有生產(chǎn)出可用工業(yè)級組件的能力，且最終將取代整個(gè)減層制造供應(yīng)鏈。其次，贊助商想藉此開始建立一個(gè)人才庫，培訓(xùn)工程師實(shí)現(xiàn)優(yōu)化利用3D打印技術(shù)進(jìn)行制造。 Williams 表示：“雖然我們還未能完全評估有多少學(xué)生正在學(xué)習(xí)3D打印，但目前所掌握的資料都是十分正面的。這些學(xué)生們一般都已經(jīng)學(xué)習(xí)3D打印技術(shù)，尤其還大量學(xué)習(xí)了機(jī)電整合。在參與這項(xiàng)競賽之前，他們幾乎都已經(jīng)具備基本知識了，并且將這項(xiàng)競賽視為一種激勵(lì)的動力，作為一個(gè)策動他們?nèi)W(xué)習(xí)一些過去一直想學(xué)卻從來沒時(shí) 間開始的理由?！? 這項(xiàng)競賽一開始總共有200名學(xué)生組成72個(gè)團(tuán)隊(duì)報(bào)名，所有的團(tuán)隊(duì)打造第一代原型進(jìn)行為期1個(gè)半月的非正式競賽。通過初賽的36組團(tuán)隊(duì)著手進(jìn)行完整的設(shè)計(jì)，最后淘汰到剩下14支隊(duì)伍——地面載具7組，以及空中載具7組。 “全部14件設(shè)計(jì)作品都是可實(shí)際操作的載具——都能飛行或或駕駛——也都有各自的強(qiáng)項(xiàng)與優(yōu)點(diǎn)，”Williams說?！氨M管在這些汽車中最后只有一輛能在這項(xiàng)競賽中勝出，但其他作品在不同項(xiàng)目的表現(xiàn)可能會更好。這就是3D打印最棒之處?！? 這項(xiàng)競賽也試圖回答兩方面的問題，一是軍事方面，另一個(gè)則與普羅大眾有關(guān)。軍 隊(duì)可在前線戰(zhàn)地部署3D打印機(jī)以及因應(yīng)需求打印出偵察機(jī)嗎？在等待救援小組到達(dá)以前，一般民眾第一時(shí)間打印出的搜救車輛能否具備展開搜救幸存者的性能？ 總決賽在2014年5月15日舉行，分別為地面車輛與空中載具設(shè)置了四關(guān)任務(wù)挑戰(zhàn)。無論是陸地行駛或空中飛行的載具都必須通過一些障礙，然后在每個(gè)關(guān)卡拍照。 Williams 解釋：“針對地面載具賽程，每個(gè)關(guān)卡都設(shè)有一些障礙，如陡坡、瓦礫場或隧道，你必須克服這些困難，或者，在其中的一個(gè)迷宮，必須展現(xiàn)急轉(zhuǎn)彎的性能。針對空 中載具賽程，則有不同的障礙，例如就像跳林波舞一樣穿過逐次降低的橫桿，或在一個(gè)開頂?shù)乃斜P旋向下并拍攝照片。其中還有一個(gè)關(guān)卡是飛近一扇窗，并在通過窗口時(shí)進(jìn)行拍照?！? 為了定量地判斷拍攝照片的質(zhì)量，每個(gè)關(guān)卡本身就像是驗(yàn)光師的視力表，經(jīng)由評分載具可清楚讀取的最低線，來決定團(tuán)隊(duì)在這一關(guān)所取得的分?jǐn)?shù)。最后只有一支團(tuán)隊(duì)分別以地面與空中載具成功地通過這項(xiàng)挑戰(zhàn)。 本文授權(quán)編譯自EE Times，版權(quán)所有，謝絕轉(zhuǎn)載 第3頁：可自行選擇打印材料，以及三種3D打印機(jī)

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{pagination} 第二部分的評分則是比賽隊(duì)伍所使用的3D打印工具。 “讓這次競賽更特別的是比賽隊(duì)伍可自行選擇3D打印的材料，這與過去的競賽規(guī)則全然不同。例如采用注塑成型和加工，限制了參賽者的創(chuàng)造力。但3D制造的本意就是在讓設(shè)計(jì)者控制每一滴材料，所以才能打印出更加復(fù)雜以及重量更輕的對象。” 在一項(xiàng)名為“積層制造最佳表現(xiàn)”的奬項(xiàng)，評分標(biāo)準(zhǔn)包括打印載具所需的組件花費(fèi)多少時(shí)間，組裝花費(fèi)多少時(shí)間、材料的使用量以及非3D打印組件數(shù)量有多少等等。 Robotics Research公司為每一支隊(duì)伍提供了電子組件工具套件。此外，所有的空中載具組必須用相同的螺旋葉片，而地面載具組則可選擇使用所提供的輪子或履帶或自行打印均可。 參 賽隊(duì)伍可選擇使用現(xiàn)有的三種3D打印機(jī)：Stratasys提供的熔融沉積(FDM)打印機(jī)；同樣由Stratasys公司提供的Poly-Jet打印機(jī) (唯一可支持從橡膠到剛性以及透明與不透明材等各種材料的打印機(jī))；以及3D Systems提供的選擇性雷射燒結(jié)(SLS)塑模3D打印機(jī)，利用高強(qiáng)度雷射光硬化燒結(jié)塑料、陶瓷、玻璃或金屬等小部份材料粉末。 他們可以從這三種打印機(jī)中選擇使用，但條件是整個(gè)載具都必須在同一臺3D打印機(jī)上進(jìn)行。這一方面為參賽團(tuán)隊(duì)賦予一些設(shè)計(jì)的空間，但又不得不在這三種3D打印技術(shù)的優(yōu)缺點(diǎn)之間進(jìn)行一些權(quán)衡折衷。4支隊(duì)伍選擇了FDM，7支隊(duì)伍選擇Poly-Jet，另3支隊(duì)伍選擇SLS。 Stiefel Family Foundation贊助了這項(xiàng)競賽的奬金——地面與空中載具組的冠軍分別可得到3,000美元，最佳表現(xiàn)與最佳設(shè)計(jì)奬分別可得3,000美元。 本文授權(quán)編譯自EE Times，版權(quán)所有，謝絕轉(zhuǎn)載 編譯：Susan Hong 參考英文原文：3D Printed Vehicles Meet US Grand Challenge，by R. Colin Johnson

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{pagination} 3D Printed Vehicles Meet US Grand Challenge R. Colin Johnson PORTLAND, Ore. — Three-dimensional printing has matured almost overnight from a novelty market for making knicknacks into a fledgling industry workhorse for making prototypes that could eventually displace the venerable manufacturing capabilities of injection molding or computer numerical control (CNC) subtractive machining, and the global tool-and-die supply chain supporting them. Today companies like Stratasys Ltd. and 3D Systems Inc. are providing the necessary industrial-grade 3D printers, but they have yet to prove the mettle of additive manufacturing to the mainstream industry. That is one reason they recently lent their expertise to the Spring 2014 Additive Manufacturing Grand Challenge, hosted by the Virginia Polytechnic Institute and State University (a.k.a. Virginia Tech) and funded by the Air Force Office of Scientific Research, the National Defense University, Robotic Research LLC, and the Stiefel Family Foundation. The Spring 2014 Additive Manufacturing Grand Challenge is hosted by Virginia Tech to demonstrate the utility of 3D printed vehicles. Christopher Williams, a professor at Virginia Tech, told EE Times in an interview: The whole point of 3D printing is to reduce the complexity of the supply chain -- thus instead of manufacturing all these pre-made parts and shipping them around the world to be assembled, you just send a 3D printer, an electronics kit, and a bucket of raw material to the place the device is needed. That's the vision. The idea of the Grand Challenge is to prove that if you send 3D printers into the field, you can print a vehicle in a few hours that is perfect for a specific mission. Today we tend to build very expensive vehicles that have to be a jack-of-all-trades, but with 3D printing you can build an inexpensive vehicle that exactly fits the needs you have at a specific site, and then put it on the shelf until its needed again -- or just throw it away. The first Additive Manufacturing Grand Challenge is open only to Virginia Tech students, but, if successfull, the hope is to duplicate it with competitions in which every major university will be able to participate. "This is the first competition of its kind," Williams told EE Times. "But it's a pilot competition that we are hoping to open up to contestants from other universities starting as early as this fall." The sponsors' motivations were twofold: first, to demonstrate that 3D additive printing is capable of more than just novelties and toys, but can produce usable industrial-grade devices that could eventually displace the whole subtractive manufacturing supply chain. Second, the sponsors want to begin creating a pool of talented engineers trained in how to make maximal use of 3D printing technology. Williams told us: We haven't finished our assessment of how much the students are learning, but the data we already have is overwhelmingly positive. The students are reporting a substantial amount of learning about mechatronics in particular and 3D printing in general. Almost all of them had minimal knowledge in these categories before the contest, and looked at the competition as a motivator, as a reason to go learn something they always wanted to learn, but never had time for. They decided, "Why not now?" Initially, 200 students signed up on 72 teams, all of which built first-generation prototypes that were put through a month-and-a-half of informal competitions. From that field, 36 teams were invited to create complete designs for evaluation, which were subsequently narrowed down to 14 -- seven ground vehicles and seven aerial vehicles. "All of the 14 vehicles are fully operational -- they all fly or drive -- but they all also have their own strengths and benefits," said Williams. "And its possible that one of these vehicles might finish last in our competition, but on a different course might do very well. That's the beauty of 3D printing." The competition attempts to answer two questions, one military and one civilian. Can the military can deploy 3D printers at forward bases and print out reconnaissance vehicles on demand? And can civilian first-responders print out search-and-rescue vehicles with just the right capabilities to start searching for survivors while waiting for the rescue teams to arrive? The finals competition is being held May 15, 2014, in a gymnasium at Virginia Tech where two courses, one for ground vehicles and one for aerial vehicles, have been set up. Each course has four waypoints, which the vehicles either drive or fly to while avoiding obstacles, and then take a picture of the waypoint. According to Williams: For the ground vehicle course, between each waypoint is an obstacle like a steep incline or a rubble field or a tunnel, where you must thread the needle, or, in one case, a maze that demonstrates sharp turning capability. The aerial vehicle's course [features] different obstacles, such as going under a bar like doing the limbo, or hovering down inside an open-top tower and taking a picture of the waypoint. And there's one waypoint that is inside a window that they have to fly close to and take the picture through the window. To quantitatively judge the quality of the picture, the waypoint itself is an optometrist's eye chart, so the judges just score the lowest line they can read to determine how many points a team receives at that waypoint. Only one team made it to the finals with two vehicles -- one ground and one aerial. And all the vehicles carry a GoPro camera as a payload, but vehicles can score extra points for carrying an additional payload. The second part of the judging is the teams' use of 3D printing. What makes this competition special is that you get to selectively place material, which is completely different from the old rules, like injection molding and machining, which constrain your creativity. But 3D manufacturing literally lets the designer control every drop of material, so we can print more complex and lighter-weight objects. In the prize category called "effective use of additive manufacturing" the judging incorporates into the score the time it takes to print the parts for the vehicle, the time it takes to assemble the vehicle, the amount of material used, and the number of non-3D-printed components. Each team got an electronic components kit from Robotics Research. In addition, all the aerial teams had to use the same rotor blades, but the ground teams got their choice of using provided wheels or treads or of printing their own. Teams each had a choice of all three types of 3D printers available today: a fused deposition modeling (FDM) printer from Stratasys; a poly-jet printer (the only one that supports a range of materials with properties from rubber to rigid and transparent to opaque) also from Stratasys; and a selective laser sintering (SLS) model, which uses a laser to harden and bond small grains of plastic, ceramic, glass, or metal, from 3D Systems. They could use any of the three printers, but the catch was that the entire vehicle had to be made on that single printer. We wanted to give them space to design, but they had to look at the tradeoffs -- the pros and cons -- between these three different technologies, which offer completely different ways of doing 3D printing. Four chose FDM, seven chose poly-jet, and three chose SLS. A total purse of $15,000 in cash prizes was made available by the Stiefel Family Foundation -- $3,000 for first prize in each category, ground and aerial, best performance and best design, plus $250 for each team that fields a functional vehicle.