現(xiàn)在，利用3D打印制作汽車部件原型的想法，已經(jīng)真正變成了一種省時省成本的成熟技術。一家立志于用3D打印技術打造整車的初創(chuàng)企業(yè)Local Motors，不僅在北美國際汽車展上展示了他們的先進技術，還將一輛汽車駛入了展區(qū)內。該公司的生產(chǎn)系統(tǒng)名為BAAM（大面積增材制造），可以實現(xiàn)大型部件的3D打印制造。
3D打印機制造商Cincinnati Inc與美國能源部下屬的橡樹嶺國家實驗室曾達成一項協(xié)議，共同開發(fā)BAAM設備與生產(chǎn)流程。Local Motors的項目是該領域中的一項嘗試，也是第一個通過“打印”技術制造汽車的項目。
雷諾電動車的“City Car”部件
當然，整輛車是無法直接打印出來的，但3D技術卻可以打印出完整的車身和底盤。Local的展車搭載了雷諾電動汽車的部件，該部件來自“City Car”的Twizy，據(jù)稱是一輛最高轉速為25mph（40kph）的社區(qū)用電動汽車。在Local公司對其進行了碰撞測試和其他測試，完成了銑削等加工工序，使其成為一輛可以出售的成品車之前，它還僅屬于概念車的范疇。Local公司表示，雷諾并非其機電部件的指定供應商，選擇雷諾參與原因很簡單，是因為他們不僅適合該項目并且有實力。
車身與底盤，甚至小到茶杯架這樣的細節(jié)，都是分成多個層面制造的，每一層都有獨自的刀位軌跡。使用的原料是粒狀的碳纖維復合材料ABS，比3D打印通常使用的塑料線便宜得多。Local公司正在進行試驗，希望可以使用濃度范圍為13%-20%的碳纖維。他們的材料供應商SABIC是一家業(yè)務涉及面廣泛的化學品與塑料生產(chǎn)商，可提供聚烯烴、聚乙烯、聚丙烯等塑料原料。
凡是車中不涉及到機械或電子功能的部件，都可以整合成一個整體，而座椅和座墊則在Local Motors的一家工廠單獨制作。
Local公司所展示的這輛車離成品還非常遙遠，從圖上就能看出這點。它的層次還相當粗糙，而且盡管機械銑削和多色制造并非高不可攀的尖端技術，但它們仍需得到驗證。
在現(xiàn)階段，觀眾看到的只是一個多部件的結合體，而且車輛的主要結構部分無論在3D打印還是銑削工藝方面，都需要大大提升精度。而要從一輛酷似高中生手工作業(yè)的項目作品提升至可以出售的商業(yè)產(chǎn)品，其中所面臨的挑戰(zhàn)巨大，遠不只是將3D打印領域多年來只專注的小型部件變得“更大、更多”那么簡單。因此，從證明工藝可行性到生產(chǎn)出可售的汽車，這一過程可能會比較漫長，而Local公司所預估的兩年時間，也許是比較樂觀的判斷。
打印時間44小時
Local的首席執(zhí)行官Jay Rogers稱，這輛名為Strati（意大利語中的意思是“層次”）的展車的生產(chǎn)時間為44小時，但他相信一輛完整的汽車可以在一天以內生產(chǎn)出來。公司將汽車的目標售價范圍定在1.8萬-3萬美元，并將客制化作為其賣點，他希望這一點可以通過軟件的改變來實現(xiàn)。
這輛車是Local能夠在全球召集到的10萬名工程師共同參與的研究成果，由公司內部團隊負責最終驗證，該團隊位于亞利桑那州的錢德勒。Rogers表示，做出貢獻的工程師們將根據(jù)其貢獻的重要性轉換成的一個專利稅點數(shù)，并獲得相應報酬。Local打算在全美范圍內開設小型工廠，每個廠房的造價約為800-1000萬美元，生產(chǎn)力約為3000輛/年，每家工廠將配置5臺或更多的3D打印機與銑削機，實現(xiàn)流水作業(yè)模式。
Rogers表示會在田納西州靠近橡樹嶺國家實驗室的地方開設第一家工廠，而第二家工廠計劃開在馬里蘭州的國際港，那是一個靠近華盛頓特區(qū)的商業(yè)開發(fā)區(qū)。如果成功，他還打算將小型工廠的計劃擴展至其他國家。
從電動汽車到越野車，再到摩托車，3D生產(chǎn)理念已經(jīng)滲入到各種機動車輛的生產(chǎn)中。在一個基于計算機技術的，生產(chǎn)工藝快速發(fā)展的時代，Local Motors可能有足夠的遠見，已經(jīng)能夠看到未來的完成品的模樣。如果它能將車展上那輛尚在基礎階段的展車提升為接近組裝車的產(chǎn)品，那么未來的市場就在前方。值得嘉許的是，除了安裝了機械和電子部件外，Local Motors并未使用任何手工精加工技術來偽裝它的作品。這家公司坦誠地表明了自己的態(tài)度：這就是我們現(xiàn)在的實力，而我們的未來，請大家拭目以待。
The idea of using 3-D “printing” to perform rapid prototyping of many automotive parts has become a well-established technology to save time and money. But Local Motors, an ambitious startup that intends to build complete cars, demonstrated its technology at NAIAS, and showed a vehicle that it drove into its display area. The production system is called “BAAM,” for Big Area Additive Manufacturing, which is a description for 3-D manufacturing of big parts.
Cincinnati Inc., a maker of 3-D printers and the Department of Energy's Oak Ridge National Laboratory have an agreement to develop the equipment and processes for BAAM. Local Motors project is just one of the efforts in this area, and the first seeking to "print" a car.
Renault EV "city car" components
All right, the entire car can’t be printed of course, but a complete body and chassis can, and the Local show vehicle is equipped with Renault electric vehicle components (from the Twizy, a “city car,”) and described as a neighborhood EV with a top speed of 25 mph (40 kph). Until Local has gone through crash and other testing, and milling and other work, to produce a finished car that can be sold, it is in the proof-of-concept category. Renault is not a designated supplier for the electrical and mechanical componentry, and was used simply because of suitability and availability for the project, the company said.
The body-chassis, down to the cup holders, is made in layered sections, with specific toolpaths for each layer. The material is a carbon-fiber composite ABS that is most readily available in pellet form and much less expensive than the more common filament plastic that normally is used in 3-D printing. Local is experimenting with carbon-fiber concentrations ranging from 13% to 20%. SABIC, which is supplying the material, is a diversified producer of chemicals and such plastic materials as polyolefins, polyethylene, and polypropylene.
Every part of the car that is not mechanically or electrically involved is fused into a single piece. Seats and cushioning will be made in a Local Motors facility.
The demonstration vehicle that Local drove into the show display is far from a finished vehicle, as a look at the illustrations indicates. The layering look is crude, and although robotic milling and multi-color manufacturing may not be insurmountable challenges, they still have to become proved processes.
At this stage the viewer sees an assemblage of parts, with one major structure that needs much more precision in both the 3-D process and the finish milling. And taking what presently resembles a high school hand-built project car to a level that will command the necessary price for a business case may be a greater challenge than just "bigger and more" of the smaller parts for which 3-D production has been used for many years. So the road from proving the process to making salable vehicles may take longer to travel than the two years in the company's optimistic projections.
"Print" time is 44 hours
Local CEO Jay Rogers said that production time for the show vehicle, called the Strati (layer in Italian) is 44 hours, but his belief is that a complete vehicle can be built in a day. The company has a target price range of $18,000 to $30,000 for vehicles, with the appeal in the idea of customization, which he hopes would become primarily a matter of a software change.
The car was the achievement of an engineering community of 100,000 worldwide that the Local startup was able to assemble, with central validation by an in-house team in Chandler, AZ. Engineering contributors will be paid on a royalty basis according to the importance of their work, Rogers said. Local intends to set up micro-factories throughout the U.S., each with an estimated cost of $8-10 million for a production capacity of about 3000 units per year, from five or more 3-D printers and milling machines, which operate in series.
Initially, Rogers said, there will be one factory in Tennessee, close to the Oak Ridge National Laboratory. A second is planned for National Harbor in Maryland, a commercial development close to Washington, D.C. If the approach is successful, he said, he envisioned micro-factories in other countries as well.
The 3-D production concept lends itself to a wide variety of motor vehicles, from EVs to off-road to motorcycles. In an era of rapid improvements in computer-directed processes, Local Motors may merely be visionary, able to see its finished projects of the future. If it can go from the rudimentary look of its NAIAS show vehicle to something more akin to kit cars, it could find a waiting market. To its credit, Local Motors did not try to disguise its vehicle with hand-finishing, beyond the installation of the electrical and mechanical parts. It delivered an apparently honest "here is where we are now, but watch us" presentation.
這是一輛由Local Motors展示的可駕駛的汽車。目前還不能呈現(xiàn)出組裝車成品的水平，但該公司并沒有對目前的技術水平進行偽裝。
近觀前擋泥板與車燈總成及壓條。
銑削機的演示，展現(xiàn)出機器人是如何對車輛進行精加工的。
3-D原型打印是由計算機控制的，通過一個顯示屏可以調整打印工藝。