3D打印逐渐发展成熟，似乎只在一夜之间，就已经从一个打印 3D 模型组件的新奇市场变成一个制造原型的新兴产业主力。最终，它还可能取代像射出成型或计算机数值控制(CMC)积层机械加工等制造能力，以及支持这些制造方式的全球工具供应链。
目前，包括Stratasys与3D Systems等公司均提供了重要的工业级3D打印机，但却还未能在主流工业领域展现积层制造的真正实力。因此，在日前由美国弗吉尼亚理工大学(Virginia Tech)主办的“2014年春季积层制造挑战赛”(Spring 2014 Additive Manufacturing Grand Challenge)，就成了证实这些3D打印工具能力的最佳机会。包括美国空军科学研究院(AFOSR)、美国国防大学(NDU)、机器人研究公司 (Robotic Research LLC,)以及Stiefel家族基金会均赞助了这项竞赛。
Virginia Tech美国弗吉尼亚理工大学主办「2014年春季积程制造挑战赛」，展示3D打印工具打造能以遥控行驶的小汽车。
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美国弗吉尼亚理工大学(Virginia Tech)主办的2014年春季积层制造挑战赛(Spring 2014 Additive Manufacturing Grand Challenge)展示实用3D打印工具，打造出可在地面行驶的汽车或空中飞行的载具。
Virginia Tech教授Christopher Williams表示：“3D打印的重点在于降低供应链的复杂度，而不是预先制造出所有的组件，然后再输送至世界各地进行组装。如今你只需要拥有一台3D 打印机、一套电子模型套件以及打造组件所需的原始材料即可。这就是3D打印的愿景。”
“这项挑战赛的想法是要证明如果您将 3D打印机送至比赛现场，你就能在几个小时内看到它制造出符合特定任务的汽车。目前的趋势是制造出多功能的昂贵汽车，但透过3D打印工具，你可以打造出完 全因应某种场合需要的低廉汽车，可在不需使用时收在架上或甚至直接丢弃，”Williams解释。
第一届积层制造挑战赛目前只开放给Virginia Tech的学生参与，如果举办成功的话，未来希望能扩大开放至每一所大学。“这是该领域的第一次竞赛，”William表示，“但我们预计这项先驱性的竞赛最快将在今秋开始也开放给其他大学共襄盛举。”
本文授权编译自EE Times，版权所有，谢绝转载
第2页：举办比赛的目的，以及厂商赞助这项竞赛的动机
第3页：可自行选择打印材料，以及三种3D打印机
相关阅读：
• 分享是美德，让我们拥抱“开放硬件平台”
• 3D打印走入彩色时代
• CES2014：智能手机绘3D打印图，3D打印走进家庭yY8esmc
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厂商赞助这项竞赛的动机有两方面：首先，为了证明3D积层打印不只是新奇的玩意儿，而是具有生产出可用工业级组件的能力，且最终将取代整个减层制造供应链。其次，赞助商想藉此开始建立一个人才库，培训工程师实现优化利用3D打印技术进行制造。
Williams 表示：“虽然我们还未能完全评估有多少学生正在学习3D打印，但目前所掌握的资料都是十分正面的。这些学生们一般都已经学习3D打印技术，尤其还大量学习了机电整合。在参与这项竞赛之前，他们几乎都已经具备基本知识了，并且将这项竞赛视为一种激励的动力，作为一个策动他们去学习一些过去一直想学却从来没时 间开始的理由。”
这项竞赛一开始总共有200名学生组成72个团队报名，所有的团队打造第一代原型进行为期1个半月的非正式竞赛。通过初赛的36组团队着手进行完整的设计，最后淘汰到剩下14支队伍——地面载具7组，以及空中载具7组。
“全部14件设计作品都是可实际操作的载具——都能飞行或或驾驶——也都有各自的强项与优点，”Williams说。“尽管在这些汽车中最后只有一辆能在这项竞赛中胜出，但其他作品在不同项目的表现可能会更好。这就是3D打印最棒之处。”
这项竞赛也试图回答两方面的问题，一是军事方面，另一个则与普罗大众有关。军 队可在前线战地部署3D打印机以及因应需求打印出侦察机吗？在等待救援小组到达以前，一般民众第一时间打印出的搜救车辆能否具备展开搜救幸存者的性能？
总决赛在2014年5月15日举行，分别为地面车辆与空中载具设置了四关任务挑战。无论是陆地行驶或空中飞行的载具都必须通过一些障碍，然后在每个关卡拍照。
Williams 解释：“针对地面载具赛程，每个关卡都设有一些障碍，如陡坡、瓦砾场或隧道，你必须克服这些困难，或者，在其中的一个迷宫，必须展现急转弯的性能。针对空 中载具赛程，则有不同的障碍，例如就像跳林波舞一样穿过逐次降低的横杆，或在一个开顶的塔中盘旋向下并拍摄照片。其中还有一个关卡是飞近一扇窗，并在通过窗口时进行拍照。”
为了定量地判断拍摄照片的质量，每个关卡本身就像是验光师的视力表，经由评分载具可清楚读取的最低线，来决定团队在这一关所取得的分数。最后只有一支团队分别以地面与空中载具成功地通过这项挑战。
本文授权编译自EE Times，版权所有，谢绝转载
第3页：可自行选择打印材料，以及三种3D打印机
相关阅读：
• 分享是美德，让我们拥抱“开放硬件平台”
• 3D打印走入彩色时代
• CES2014：智能手机绘3D打印图，3D打印走进家庭yY8esmc
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第二部分的评分则是比赛队伍所使用的3D打印工具。
“让这次竞赛更特别的是比赛队伍可自行选择3D打印的材料，这与过去的竞赛规则全然不同。例如采用注塑成型和加工，限制了参赛者的创造力。但3D制造的本意就是在让设计者控制每一滴材料，所以才能打印出更加复杂以及重量更轻的对象。”
在一项名为“积层制造最佳表现”的奬项，评分标准包括打印载具所需的组件花费多少时间，组装花费多少时间、材料的使用量以及非3D打印组件数量有多少等等。
Robotics Research公司为每一支队伍提供了电子组件工具套件。此外，所有的空中载具组必须用相同的螺旋叶片，而地面载具组则可选择使用所提供的轮子或履带或自行打印均可。
参 赛队伍可选择使用现有的三种3D打印机：Stratasys提供的熔融沉积(FDM)打印机；同样由Stratasys公司提供的Poly-Jet打印机 (唯一可支持从橡胶到刚性以及透明与不透明材等各种材料的打印机)；以及3D Systems提供的选择性雷射烧结(SLS)塑模3D打印机，利用高强度雷射光硬化烧结塑料、陶瓷、玻璃或金属等小部份材料粉末。
他们可以从这三种打印机中选择使用，但条件是整个载具都必须在同一台3D打印机上进行。这一方面为参赛团队赋予一些设计的空间，但又不得不在这三种3D打印技术的优缺点之间进行一些权衡折衷。4支队伍选择了FDM，7支队伍选择Poly-Jet，另3支队伍选择SLS。
Stiefel Family Foundation赞助了这项竞赛的奬金——地面与空中载具组的冠军分别可得到3,000美元，最佳表现与最佳设计奬分别可得3,000美元。
本文授权编译自EE Times，版权所有，谢绝转载
编译：Susan Hong
参考英文原文：3D Printed Vehicles Meet US Grand Challenge，by R. Colin Johnson
相关阅读：
• 分享是美德，让我们拥抱“开放硬件平台”
• 3D打印走入彩色时代
• CES2014：智能手机绘3D打印图，3D打印走进家庭yY8esmc
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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.
责编：Quentin
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