Norsk Titanium AS公司憑借在快速等離子沉積工藝（Rapid Plasma Deposition，RPD）方面超過10年的研發(fā)經(jīng)驗(yàn)，聲稱有能力以25%-50%的成本，提供同類鈦材料組件。具體來說，Norsk公司會(huì)將室溫狀態(tài)下的6-4鈦絲送入在氬氣環(huán)境中由一對等離子發(fā)生器產(chǎn)生的等離子弧。此后，鈦絲原料的溫度將快速上升至上千攝氏度，然后作為一種液體材料，供機(jī)械沉淀臂打印使用。沉積后的液體鈦材料將立即凝固?？傮w來說，組件將在這樣的閉環(huán)工藝過程中快速層疊成型，可以最大程度降低精加工需求。
事實(shí)上，MERKE IV RPD設(shè)備與標(biāo)準(zhǔn)的計(jì)算機(jī)數(shù)控加工中心(CNC)很類似，只不過使用的是等離子弧，而不是軸而已。Norsk公司總裁兼CEO Warren Boley表示，MERKE IV RPD設(shè)備“每年可以打印20噸鈦材料”，而且“將真正改變航空器級鈦材料零部件的生產(chǎn)現(xiàn)狀。”
今年4月，總部位于奧斯陸的Norsk公司宣布，公司將為波音787 Dreamliner夢幻客機(jī)提供3D打印RPD工藝結(jié)構(gòu)性鈦材料組件。波音公司在組件的整個(gè)開發(fā)設(shè)計(jì)過程中一直與Norsk保持密切合作。此外，為了驗(yàn)證這些原始結(jié)構(gòu)性組件在Dreamliner夢幻飛機(jī)上的表現(xiàn)，波音公司還與Norsk一起聯(lián)合美國聯(lián)邦航空管理局(FAA)進(jìn)行了一系列嚴(yán)格的測試，并在今年2月完成了認(rèn)證。Norsk公司是首家為波音提供RPD工藝組件的供應(yīng)商。
波音公司飛機(jī)材料與結(jié)構(gòu)、供應(yīng)商管理副總裁John Byrne表示，“我們總是在探索最新的技術(shù)，從而降低成本、提升性能并給我們的客戶創(chuàng)造更多價(jià)值，Norsk的RPD工藝完全符合我們的要求。”
Norsk公司聲稱，RPD工藝的生產(chǎn)成本低于傳統(tǒng)的鍛造和制造工藝技術(shù)，而后者需要使用鈦坯料作為加工原材料。
“你可以找一塊200磅的材料進(jìn)行鍛造，然后生產(chǎn)一個(gè)20磅的部件，”Boley表示，“而我們可以直接用30磅的材料打印一個(gè)20磅的部件。”通常來說，采用傳統(tǒng)加工工藝的組件交貨期在55到75周左右，而如果采用我們的RPD工藝，這些組件的打印和加工完全可以在2到3小時(shí)內(nèi)完成。
Norsk表示，由于這種增材工藝本身可以在生產(chǎn)過程中節(jié)省大量能耗，因此能夠節(jié)省75%的成本，并顯著節(jié)省工時(shí)。
Boley認(rèn)為，波音787中大約有1,000個(gè)組件均可采用RPD工藝，“每個(gè)部件大約可以節(jié)省2,500美元，那么整部飛機(jī)則可以節(jié)省接近250萬美元的成本。如果按照每年生產(chǎn)144架飛機(jī)計(jì)算，波音每年可以節(jié)省3.6億美元。這可是革命性的進(jìn)展！”
Norsk公司也非常注意RPD工藝對環(huán)境的影響。通過減少浪費(fèi)的廢鈦（傳統(tǒng)工藝鈦材料組件的成品與原材料之間的重量比大約為1:40），RPD工藝還可以減少礦石的開采加工需求。
Dreamliner的RPD組件以及生產(chǎn)這些組件的NorskTitanium MERKE IV RDP加工設(shè)備均參加了今年6月在法國Le Bourget舉辦的巴黎國際航展。
Norsk Titanium AS—which has been researching and developing its RPD (rapid plasma deposition) process for over 10 years—says it can produce titanium components that can cost from 50 to 75% less than other equivalent components. Its process involves feeding room-temperature titanium 6-4 wire into a plasma arc created by a pair of torches in argon gas environment. The titanium temperature is raised by thousands of degrees and then is robotically printed as a liquid by a robotic depositing arm. The titanium solidifies instantly after being deposited. The component is rapidly built up in layers in a closed-loop process and requires very little finish machining.
The system itself, a MERKE IV RPD machine, bears a resemblance to a standard computer numerical control (CNC) machining center—with a plasma arc instead of a spindle. Norsk President and CEO, Warren Boley stated that the MERKE IV RPD machine “can print 20 tons of titanium per year,” and that it’s “a game changer in terms of being able to produce aircraft quality titanium parts.”
This past April, Oslo-based Norsk announced that it will be producing via RPD 3D-printed structural titanium components for the Boeing 787 Dreamliner. Boeing designed the components and collaborated closely with Norsk throughout the development process. To certify these initial structural components on the Dreamliner, Boeing and Norsk undertook a rigorous testing program with Federal Aviation Administration (FAA) certification deliverables completed in February. Norsk is the first supplier for Boeing’s high deposition rate material specification.
“We are always looking at the latest technologies to drive cost reduction, performance, and value to our customers and Norsk’s RPD capability fits the bill in a new and creative way,” said John Byrne, Vice President, Airplane Materials and Structures, Supplier Management, Boeing Commercial Airplanes.
Norsk claims that the production cost is less than that of legacy forging and manufacturing techniques where billets of titanium are machined into components.
“You can take a 200-lb forging and produce a 20-lb part,” said Boley. “We can print 30 lb of material to produce a 20-lb part.” Producing a 200-lb billet and machining it down to a 20-lb component typically requires a lead time of 55 to 75 weeks. These same components can be created via RPD and machine finished within 2 to 3 hours.
Because of the significant reduction of waste and machining energy inherent in their additive process, Norsk claims up to 75% cost and time savings.
With an estimated 1000 titanium components in a Boeing 787 that can be manufactured using the RPD process, Boley stated that, “We think we can save $2500 per part; that’s $2.5 million per aircraft. At 144 aircraft a year, that’s $360 million. That kind of saving is revolutionary.”
Norsk also takes note of the environmental impacts that its RPD process brings as well. By reducing the amount of scrap titanium (approximately 40 lb of scrap to 1 lb that sees flight), the process also reduces the amount of ore that must be mined and processed.
The Dreamliner RPD components—as well as Norsk Titanium’s MERKE IV RDP machine that produced them—will be on display at the International Paris Airshow, Le Bourget in June.
Author: William Kucinski
Source: SAE Aerospace Engineering Magazine
Norsk公司MERKE IV RPD加工設(shè)備的內(nèi)部環(huán)境。
采用Norsk RPD工藝打印的鈦材料結(jié)構(gòu)性部件：未完成階段（左）、初級加工階段（中）、最終精加工成品（右）。
Dreamliner的RPD組件以及生產(chǎn)這些組件的Norsk Titanium MERKE IV RDP加工設(shè)備均參加了今年6月在法國Le Bourget舉辦的巴黎國際航展。
