增材制造（AM）技術(shù)正在強(qiáng)勢登陸航空航天業(yè)生產(chǎn)領(lǐng)域?？湛团c火箭制造商聯(lián)合發(fā)射聯(lián)盟（ULA）將在飛行器上使用Stratasys生產(chǎn)的3D打印部件。
這家增材制造方案供應(yīng)商在今年5月宣布，空客公司已在其Stratasys FDM（熔融沉積成型） 3D生產(chǎn)系統(tǒng)上了生產(chǎn)了1000多個飛行部件，用于2014年12月上市的A350 XWB機(jī)型。一名Stratasys發(fā)言人表示，空客選擇將一些以傳統(tǒng)方式生產(chǎn)的輕型或無負(fù)載的內(nèi)飾部件替換成3D打印部件，目的是在達(dá)成交貨承諾的同時提高供應(yīng)鏈的靈活性。
2013年，空客公司與Stratasys聯(lián)手發(fā)起3D打印的開發(fā)和認(rèn)證活動，目的是為了降低生產(chǎn)進(jìn)度方面的風(fēng)險。
“只要得到自動化生產(chǎn)所需的數(shù)字文件，并具備合格且適當(dāng)?shù)臋C(jī)器設(shè)備，無論你身處哪里都能進(jìn)行部件的生產(chǎn)，” Stratasys航空航天與防御業(yè)務(wù)發(fā)展經(jīng)理Scott Sevcik告訴《航空航天工程雜志》。“這意味著研發(fā)階段無需更多考慮制造和采購方面的限制因素，可以依據(jù)特定采購要求進(jìn)行決策，靈活變化，而不需要在整個項目生命周期中固定選擇某一項設(shè)計。此外，這種生產(chǎn)不需要使用額外的工具，這意味著在改變部件時無需對工具進(jìn)行相應(yīng)的變更。要知道修改工具可能耗費(fèi)數(shù)周或數(shù)月之久，而且這段時間內(nèi)還不能進(jìn)行生產(chǎn)。因此，生產(chǎn)部件的地點和方式變得更加靈活，而更短的修改周期則意味著你可以更自由地掌控改善設(shè)計的時間，而且變更所造成的影響也更小。”
這些3D打印部件的原材料是FDM專用的ULTEM 9085樹脂，該材料已獲得空客公司的材料規(guī)范認(rèn)證。ULTEM 9085熱塑材料的強(qiáng)重比極高，而且它的FST（火焰、煙塵和毒性）特性也符合飛機(jī)內(nèi)飾的規(guī)范。這一工藝使空客公司不僅能夠生產(chǎn)出更輕便的部件，而且還能“大大降低”生產(chǎn)時間和成本。
“此外，因為減少了傳統(tǒng)生產(chǎn)方法中不可避免的材料浪費(fèi)，增材制造還能夠顯著提高BTF比率（原材料與成品零件之間的重量比），” Stratasys市場推廣與垂直解決方案部門事業(yè)開發(fā)執(zhí)行副總裁Dan Yalon表示。“Stratasys期待著在與空客的合作中發(fā)揮上述及其他優(yōu)勢，并成為空客‘未來工廠計劃’的一部分。”
在一個視頻中（ https://www.youtube.com/watch?v=Cy3V3KR1LWc&feature=youtu.be），空客公司的專家講解了增材制造將在未來幾年內(nèi)對航空航天業(yè)產(chǎn)生怎樣的影響。講解專家在視頻中提到，“從長遠(yuǎn)來看，3D打印將使每一架飛機(jī)減少1噸以上的重量。”
ULA使用3D打印技術(shù)生產(chǎn)運(yùn)載火箭的“flight-ready” (意為隨時可以升空)部件，生產(chǎn)成本為1.65億美元，達(dá)到了該種部件成本的最低水平。這些部件將用于重達(dá)6萬磅以上的航天衛(wèi)星的推進(jìn)。ULA為NASA、美國空軍和商業(yè)火箭公司等機(jī)構(gòu)生產(chǎn)運(yùn)載火箭。
ULA不斷推進(jìn)3D打印技術(shù)，從原型機(jī)到工具，而現(xiàn)在已進(jìn)入飛行硬件的生產(chǎn)。在購入Stratasys公司的2臺Fortus 900mc 3D生產(chǎn)系統(tǒng)之后，ULA開始更新Atlas V火箭上的環(huán)境控制系統(tǒng)（ECS）導(dǎo)管，搭載全新3D部件的火箭預(yù)計將于2016年升空。ECS導(dǎo)管負(fù)責(zé)將氮氣輸送至火箭助推器的電子部件。
工程師們在使用FDM系統(tǒng)修改設(shè)計后，將ECS管道總成的部件從140個合并至16個。ULA表示，這樣做大大減少了安裝時間，并降低了57%的部件生產(chǎn)成本。
“ULTEM 9085在極寬的溫度變化范圍內(nèi)都能保持極高的強(qiáng)度，” ULA增材制造項目經(jīng)理Greg Arend表示。“我們已經(jīng)通過測試證明，該材料能承受從低溫到高熱的溫度范圍，而且還能承受住升空與飛行產(chǎn)生的振動與壓力。”
ULA計劃在下一代火箭上將3D打印部件的數(shù)量增加至100個以上。
“我們確實能夠在很多應(yīng)用中使用這種高強(qiáng)度熱塑材料，因此我們正在將許多金屬替換成塑料，要知道塑料的成本要低很多，”ULA材料處理工程師Andrea Casias表示。
“目前的運(yùn)載火箭上，3D打印的飛行部件的數(shù)量正在猛增，”Arend補(bǔ)充道。“而且我們還打算在Vulcan火箭上大量使用3D打印部件。”
航空航天業(yè)市場規(guī)模較小，但復(fù)雜程度極高，是增材制造技術(shù)理想的應(yīng)用領(lǐng)域，Stratasys的Sevcik表示。“2014年初，我們與兩家公司討論過飛行應(yīng)用材料的認(rèn)證問題，而現(xiàn)在已經(jīng)有十多家公司開始關(guān)注這一領(lǐng)域。”
Sevcik還提到：“可打印部件的類型是由我們可以提供的材料類型所決定的，目前我們只能打印某些不需要負(fù)重的部件，但我們也在與航空航天業(yè)的關(guān)鍵客戶探討，如何讓該技術(shù)走得更遠(yuǎn)。隨著材料和工藝方面的不斷改進(jìn)，我們能實現(xiàn)的應(yīng)用也越來越多，”其中包括整個飛機(jī)和發(fā)動機(jī)中的結(jié)構(gòu)部件和關(guān)鍵飛行部件。
3D-printed parts fly on Airbus A350 XWB and ULA rockets
Additive manufacturing (AM) is making significant headway in aerospace production programs, as evidenced by recent announcements that Airbus and rocket manufacturer United Launch Alliance (ULA) both are—or soon will be—flying aircraft that incorporate 3D-printed parts enabled by Stratasys.
The AM solutions provider announced in May that Airbus has produced more than 1000 flight parts on its Stratasys FDM (Fused Deposition Modeling) 3D Production Systems for use in the A350 XWB aircraft, delivered in December 2014. Airbus chose to replace certain traditionally manufactured parts—lightly- or non-loaded interior components, according to a Stratasys spokesperson—with the 3D-printed ones in an effort to increase supply chain flexibility, which the company achieved while meeting its delivery commitment.
Airbus initiated development and certification of 3D printing with Stratasys in 2013 as a schedule risk reduction activity.
“With a digital file as the basis for automated production, wherever you have the appropriate, qualified machine to produce the part, you can,” Scott Sevcik, Stratasys’ Aerospace & Defense Business Development Manager, shared withAerospace Engineering. “This shifts the make-buy decision out of the development phase, and can be a decision made based on the needs of the specific procurement rather than a design choice for the life of the program...Also, because you are producing a part without tooling, changes to the part can occur without involving a change to tooling, which can take weeks or months out of the procurement cycle. So you have more flexibility in where and how you produce the parts, and the shorter change cycle enables flexibility to improve designs over time with less impact.”
The parts are 3D-printed using ULTEM 9085 resin for FDM, which is certified to an Airbus material specification. ULTEM 9085 thermoplastic provides high strength-to-weight ratio and is FST (flame, smoke, and toxicity) compliant for aircraft interior applications. The process enables Airbus to manufacture lighter weight parts while “substantially reducing” production time and manufacturing costs.
“Additive manufacturing also greatly improves the buy-to-fly ratio as significantly less material is wasted than with conventional manufacturing methods,” said Dan Yalon, Executive Vice President, Business Development, Marketing & Vertical Solutions for Stratasys. “Stratasys is looking forward to bringing these and other advantages to its collaboration with Airbus and to being part of Airbus’ Factory of the Future initiative.”
Airbus provides insight into how additive manufacturing, in general, will impact its business in the coming years in this video: https://www.youtube.com/watch?v=Cy3V3KR1LWc&feature=youtu.be. The narrator states in the video that “in the long term, 3D printing could reduce weight on each aircraft by more than a ton.”
ULA uses 3D printing to produce flight-ready parts for its launch vehicles, which cost at the lower end about $165 million and are used to propel into space satellites that can weigh more than 60,000 lb. The company makes launch vehicles forNASA, the U.S. Air Force, and commercial satellites.
ULA progressed its use of 3D printing technology from prototyping to tooling and then to flight hardware production. After acquiring two Fortus 900mc 3D Production Systems from Stratasys, the company began updating the environmental control system (ECS) duct on the Atlas V, which is expected to launch with the new 3D component in 2016. The ECS duct delivers nitrogen to electronic components within the rocket booster.
Engineers consolidated the number of parts for the ECS duct assembly from 140 to 16 parts by using FDM technology to modify the design. This “significantly reduces” installation time and results in a 57% part-cost reduction, the company claims.
“ULTEM 9085 has great strength properties over a wide temperature range,” said Greg Arend, Program Manager for Additive Manufacturing at ULA. “We have done testing to show that it is very capable of withstanding temperatures from cryogenic all the way up to extreme heat. And it’s tough enough to handle the vibration and stress of lift off and flight.”
ULA plans to increase the quantity of 3D-printed parts to more than 100 on the next-generation rocket.
“In a lot of cases, because we do have the ability to use this high-strength thermoplastic, we’re actually replacing a lot of metallic applications with plastic applications because it’s substantially less expensive,” said Andrea Casias, Materials Process Engineer at ULA.
“We see somewhat of an exponential growth in the utility of 3D printing for flight applications on our current vehicles,” added Arend. “And we intend to use it heavily with our Vulcan rocket.”
The lower volume, higher complexity nature of the aerospace industry is an ideal fit for additive manufacturing, according to Stratasys’ Sevcik. “In early 2014, we were in discussion with two companies on certifying material for flight applications; today we’re talking to more than 10.
“The type of parts that can be printed will be driven by the type of materials we can offer,” he continued. “Right now, we’re limited to certain applications that aren’t heavily load bearing, but we are working with key customers in the aerospace industry to advance the technology even further. As we continue to improve the material and process offerings, we will be able to address more and more applications,” including structural and flight-critical content throughout the aircraft and engines.
空客公司已用Stratasys FDM 3D生產(chǎn)系統(tǒng)生產(chǎn)了1000多種飛行部件，用于一類A350 XWB機(jī)型。
聯(lián)合發(fā)射聯(lián)盟將用3D打印技術(shù)生產(chǎn)即可飛行部件，其中包括Atlas V火箭上的環(huán)境控制系統(tǒng)（ECS）導(dǎo)管，搭載新部件的火箭預(yù)計將于2016年升空。（ULA）
ULA選擇ULTEM 9085作為打印材料，因為它能承受大范圍的極限溫度。圖為Atlas V火箭上3D打印的ECS導(dǎo)管。(ULA)