3D printer manufacturerAscend Manufacturing已经揭示了其新型大面积投影烧结（LAPS）3D打印方法的内部工作。
3D印刷行业在接受贾斯汀·努斯鲍姆（Justin Nussbaum）公司的创始人兼首席执行官采访时，发现了有关新方法背后的闭环添加剂制造技术的更多信息。Nussbaum将粉末床融合（PBF）技术描述为选择性激光烧结（SLS）和无膜片投影立体光刻的组合。3D打印机使用包括热摄像机在内的闭环系统，能够不断监视和调整粉末床的温度，而无需用户输入。简化的制造过程可确保床在恒定的温度下均匀加热，这使整个零件层都能一次制造。
“Our process disconnects the layer time from the overall manufacturing time. As we scale the system up, it still takes the same amount of time to fuse a layer, but we can now fuse a lot more parts in the same amount of time. Our production systems will literally be capable of making hundreds of thousands of parts, in a single day,” said Nussbaum.
Ascend Manufacturing
制造技术是由努斯鲍姆（Nussbaum）开发的，同时攻读博士学位。在南佛罗里达大学。After founding Ascend Manufacturing in 2018, the graduate was awarded $500,000 to commercialize the technology as part of the Innovation Crossroads scheme byOak Ridge National Laboratory(ORNL). Facilities at ORNL have provided all the advanced testing equipment necessary to progress the technology, with CT scanners, 3D microscopes, and a research team to support its development.
The startup is now looking for additional investment, to make its next step from the laboratory, to commercial production, with the aim of filling what it perceives as a gap in the market for a “middle volume” production service.
“There’s a disparity between ordering ten or one hundred parts and very high volumes. That’s where 3D printing is really starting to shine. What we want to do is help to bridge that gap and make a disconnect between the price and part quantity. So, whether you wanted one part or a million of them, you can have them manufactured for the same price per part.”
Nussbaum credits the “newer players” in 3D printing, for taking a similar approach to medium volume production, such asHP及其多喷射融合技术。Nonetheless, he remains adamant that his LAPS system is very different to other SLS-based machines.
Large Area Projection Sintering Technology
圈速工艺涉及使用高强度投影仪将图像投放到粉末床上。然后将材料融合到该形状中，使整层立即生产，并断开从整个制造时间创建一层所花费的时间。随着公司的构建体积增加和较大的床，层的生产时间却没有增加，但是它可以一次融合更多的零件。
The LAPS system’s optical and thermal camera not only supervises the process but is also able to control it. During layer formation, the thermal camera is able to monitor the temperature of the bed in real-time, and update the image being sent to the projector so that the whole area is fused at an even temperature. As a result, fewer user inputs are necessary, with only temperature and time parameters required, which acts to reduce the level of expertise necessary to operate the machine.
According to Ascend, other high-speed sintering techniques heat the whole powder bed but at varying temperatures across the bed, which limits the plastics that can be used. The LAPS system, on the other hand, has been compatible with every tested material so far, ranging from low cost to high-performance materials. Parts produced during testing exhibited 100% density with no visible pores and a side wall finish that is comparable to those produced using SLS or MDF 3D printers. The top surfaces of the products were also smooth, with a surface roughness that’s measurable in nanometers.
“饰面很光滑，是一种塑料，但最终会反射。这给了我们一些优势，特别是用于印刷的电子设备，如果您的表面粗糙，这会变得困难。”
A total of $1m has been invested in the project since 2015, with Innovation Crossroads providing $500k in funding through ORNL and an additional $500k being provided by multiple grants from theNSF, State of Tennessee and the南佛罗里达大学。Additional funding is now being sought to take the initial step of becoming a contract manufacturer. In this role, the company would sell services and components such as tools and fixtures, in addition to other end-use components for consumer goods.
最终，鉴于零件在测试过程中表现出的重量强度比增强的长期目标是为航空航天和国防行业开发组件。尽管Covid-19造成的业务中断，但该公司计划在年底之前赚取收入，目的是在2021年开始提供服务。
Closed-loop additive manufacturing
Although full closed-loop control has not yet been commercialized in SLS 3D printing, it has been utilized by researchers and companies for other means.
Researchers from theArgonne国家实验室added an infrared camera, capable of capturing融化颗粒的热特征以每秒100000帧(fps) PBF体制m in September 2018. The device’s addition to the 3D printer reflected a doubling down of the lab’s efforts to enhance the reproducibility of PBF processes.
Chicago-based metal 3D printer manufacturerSciaky Inc带来了闭环控制2016年2月，其电子束添加剂制造（EBAM）机器。
The nominations for the2020 3D Printing Industry Awards现在开放。您认为谁应该在今年的演出中列出入围名单？现在有发言权。
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Featured image shows the Oak Ridge National Laboratory, where Ascend’s LAPS technology is being developed. Photo via Ascend Manufacturing.
