Posted on

AFRL and University Partners Used 3D Printed Composite Materials to Make Structural Parts

The Air Force Research Laboratory (AFRL), located at Wright-Patterson Air Force Base (WPAFB) near my hometown of Dayton, Ohio, has long been interested in using 3D printing and composite materials for the purposes of aerospace applications. Last year, AFRL’s Composites Branch at the Materials and Manufacturing Directorate partnered up with researchers from the University of Arkansas, the University of Miami in Florida, Louisiana Tech University, and the University of Texas at El Paso (UTEP) to work on advancing 3D printable composite materials.

The Composites Branch works on the research and development of organic and ceramic matrix composite technologies for legacy, developmental, and future Air Force system components. Together with its university partners, the AFRL branch demonstrated 3D printed composite materials, made from a combination of carbon fiber and epoxy, which had been successfully fabricated and used to make structural parts on both air and space craft. The results of this 3D printed composite material effort will soon be published in a special issue of the Journal of Experimental Mechanics that’s dedicated to the mechanics of 3D printed materials.

Dr. Jeffery Baur, leader of the Composite Performance Research Team, said, “The potential to quickly print high-strength composite parts and fixtures for the warfighter could be a tremendous asset both in the field and for accelerating weapon system development.”

Composite materials are made up of two, or sometimes more, constituent materials that have very different chemical or physical properties. When combined, these components produce a new material that has characteristics which are different from the originals. The individual components that make up the composite will remain distinctly separated within the final material structure.

When compared to the more low-quality polymers that are typically used in 3D printers, the composite materials demonstrated by AFRL and its partners are the same type that are already being used to make Air Force system components. These materials are very strong, while also lightweight, and have higher thermal and environmental durability than most.

Most traditional epoxy and carbon fiber composites are made by layering carbon fiber sheets, coated with epoxy resin, on top of each other. Then, the whole thing is cooked for hours in a costly pressure cooker to finish. The major downside to this method is that it’s more difficult to create parts that have complex shapes when sheets are being used.

This is where additive manufacturing comes in. Composite materials that are 3D printed are able to create parts with those complex shapes, and additionally don’t require the use of long heating cycles or expensive pressure cookers. On a materials level, there aren’t a whole lot of downsides to using composites for the purposes of producing, assembling, or repairing parts for the Air Force, whether at the depot or out in the field.

Military branches in other countries are also seeing the benefit of 3D printable composite materials. For example, engineers in India are manufacturing complex core structures using the composite 3D printing process; when combined with top and bottom face sheets, these structures will create lightweight sandwich structures that have properties tailored specifically to, as AFRL put it, “the physical forces that need to be carried.”

Conventionally fabricated sandwich structures use the same core geometries over the entire area of an aircraft skin, but a 3D printed version would be able to stand up under heavier forces when necessary, while also remaining lightweight in other parts of the skin.

Discuss this story and other 3D printing topics at 3DPrintBoard.com or share your thoughts in the Facebook comments below.

[Source: Dayton Daily News]

Posted on

3D Printing News Briefs: November 13, 2018

We should really call today’s 3D Printing News Briefs the formnext 2018 Briefs, as announcements from the show are numerous this week. EnvisionTEC, XYZprinting, BASF, and DSM all introduced new 3D printing materials at the event in Frankfurt today, and in the only news not related to formnext, Imerys Ceramics has announced a new range of ceramic feedstocks.

EnvisionTEC Debuting First 4K 3D Printing System

At formnext, 3D printer manufacturer EnvisionTEC debuted the industry’s first DLP-based 3D printer that uses a true 4K projector with UV optics tuned to the 385 nm wavelength. Available in three production-ready variations, with a gray body and a 2560 x 1600 pixel projector resolution, the Perfactory P4K 3D printer delivers highly accurate parts with an ultra-smooth surface finish. Additionally, the Perfactory P4K, has access to the rest of the Perfactory line’s versatile materials portfolio for production capacity.

“The P4K is the highest resolution advanced DLP printer with the largest build envelope and deploys artificial intelligence in pixel modulation to deliver the highest accuracy parts with the smoothest available surface finish in the 3D printing space. This will deliver the next level of production-grade 3D printing solutions,” said Al Siblani, the CEO of EnvisionTEC.

The new Perfactory P4K will be on display at formnext all week.

XYZprinting Introducing New 3D Printing Materials

Another company introducing new materials at formnext this week is desktop 3D printing brand XYZprinting. In order to expand the capabilities of both domestic and professional grade 3D printers, the company is launching a new antibacterial PLA material, along with copper metallic PLA and Carbon PLA materials. The first of these can destroy up to 99% of bacteria, including E. coli and Staphylococcus aureus, and comes in four colors: white, red, yellow and neon green.

The copper metallic PLA, made of 65% copper powder, is a good alternative for hobbyists when it comes to sculpting metal for ornamental models. The material is being launched in conjunction with XYZprinting’s new nozzle, made of carbon hardened steel. Finally, the new Carbon PLA, which is also compatible with this new nozzle, is made of 10% carbon fiber, and its matte finish is ideal for showing off fine details. You can learn more about these new materials at XYZprinting’s booth D10 in Hall 3.1, where it will also be exhibiting its latest 3D printer, the da Vinci Color AiO, with a 3D scanner and optional laser engraver.

BASF 3D Printing Solutions Presents New Products at formnext

Germany-based BASF 3D Printing Solutions GmbH (B3DPS), a 100% subsidiary of BASF New Business GmbH, is also at formnext this week, to introduce several new materials for photopolymer and laser sintering methods, in addition to announcing some new partnerships and alliances. First, B3DPS is introducing flame-resistant Ultrasint Polyamide PA6 Black FR, Ultrasint PA6 Black LM X085, which is suitable for most current SLS 3D printers, and Ultrasint PP, a polypropylene with great plasticity, low moisture uptake, and resistance to liquids and gases. Additionally, B3DPS has also grouped its photopolymer materials under the new Ultracur3D brand name.

András Marton, Senior Business Development Manager at B3DPS, said, “Our Ultracur3D portfolio enables us to offer customers various UV-curable materials for 3D printing that provide far better mechanical properties and higher long-term stability than most available materials.

“These materials have been developed for functional components that are subject to high stress.”

The subsidiary also announced that it’s partnering with California company Origin and 3D printer manufacturer Photocentric to develop photopolymers and photopolymer 3D printing processes, and working with Chinese 3D printer manufacturer Xunshi Technology, which operates in the US under the name SprintRay, to open up new applications for the Ultracur3D range. Additionally, B3DPS subsidiary Innofil3D is partnering with Jet-Mate Technology in China and US-based M. Holland to distribute plastic filaments. Visit B3DPS at formnext this week at booth F20 in Hall 3.1.

DSM Announces 3D Printing Product Launches

Vent cover used for PIV windtunnel testing, printed in Somos PerFORM Reflect

In today’s final formnext news, science-based company DSM has unveiled two new high-performance materials for 3D printing structural parts. Somos PerFORM Reflect is a groundbreaking new stereolithography material for wind tunnel testing with PIV (Particle Imaging Velocimetry), and saves more than 30% post treatment cost by eliminating the need to apply PIV coatings to printed parts. In addition to helping customers conduct iterations and collect data more quickly, the resin could actually help break speed records for wind tunnel testing.

“Speed is crucial, whether in automotive, aerospace or other transportation design. Eliminating the need to apply PIV coatings is a major breakthrough for customers who are using PIV wind tunnel testing. It allows them to speed up their aerodynamic design optimizations. We are thrilled that our strategy of focusing on helping customers create their applications have enabled us to deliver such tremendous value. Overnight, Somos® PerFORM Reflect will not just set new speed records but new industry standards,” said Hugo da Silva, Vice President of Additive Manufacturing at DSM.

The company’s second new material is the thermoplastic copolyester (TPC) Arnitel ID2060 HT, which is perfect for the FDM 3D printing of structural parts for automotive applications. The material features a balance of prolonged high temperature resistance, flexibility, and chemical resistance against exhaust gas recirculation (EGR) condensate.

Imerys Ceramics Introduces EZ Print 3D Range of Ceramic Feedstocks

As part of the Imerys group, Imerys Ceramics designs, produces, and markets high-performance mineral solutions for the ceramic industries, and is making ceramic 3D printing easy with its new, unique range of ceramic materials called EZ Print 3D.

EZ Print 3D is available as a plug & play cartridge, so users can enjoy efficiency and ease of use when it comes to 3D printing. The materials are also available as a “ready to fill” ceramic feedstock, and have been tested on several 3D printers currently on the market. EZ Print 3D has a low firing temperature of 1220°C that’s compatible with most kiln temperature limits, and the genuine low porosity (<0,5%) of a porcelain. The technology is perfect for tableware and giftware applications, and the company plans to expand EZ Print 3D accordingly as 3D printing adoption grows. Imerys Ceramics also provides technical support and a dedicated team that’s competent in 3D printing to help customers.

Discuss these stories and other 3D printing topics at 3DPrintBoard.com or share your thoughts in the Facebook comments below.

Posted on

New Study Shows that SLM 3D Printing Has High Potential for Fabricating Metallic Glass Components

Metallic glass, also known as amorphous metal, was first introduced in the early 1960s, and since then, it seems that everyone wants in on the action. The material is valued for its many exceptional properties, such as low stiffness, near-theoretical strength, high corrosion resistance, and large elastic strain limits. Bulk metallic glasses (BMG), which have characteristic specimen sizes in excess of 1 mm, have been explored successfully for for glass formers.

It’s not easy to produce metallic glasses with complex geometry, because the molten alloys must be cooled rapidly to move past the nucleation and growth of crystals, and most commonly used methods, such as melt spinning, casting, and powder metallurgy, are limited in both complex geometry and dimension. That’s why it’s so important to continue exploring and developing more novel processing routes for producing amorphous components.

A schematic illustration of SLM-YZ250 3D printer: (a) operating mode of the device; (b) processing scanning pattern.

A team of researchers from the University of Science and Technology Beijing have been investigating the use of selective laser melting (SLM, also called DMLS, Direct Metal Laser Sintering, Powder Bed Fusion, Laser Powder Bed Fusion) 3D printing to fabricate Fe-based metallic glass powder with unrestricted, complex geometry. This specific technology offers very high cooling rates, which is important for glass formation of most BMGs, and can apply various processing parameters involving laser energy density to melt the metal powder.

The researchers recently published a paper, titled “Fabrication and characterization of Fe-based metallic glasses by Selective Laser Melting,” in the Optics and Laser Technology journal. The paper details SLM’s high potential for 3D printing metallic glass components with complex geometries.

The abstract reads, “Fe-based metallic glasses (MGs) can be potential structural materials owing to an exceptional combination of strength, corrosion and wear resistance properties. However, many traditional methods are difficult to fabricate Fe-based MGs with complex geometry. In this study, a new metallurgical processing technology, selective laser melting (SLM), was employed to fabricate Fe-Cr-Mo-W-Mn-C-Si-B metallic glasses. The microstructure, thermal stability and mechanical properties of the as-fabricate samples processing with different laser energy density have been investigated by X-Ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and nano-hardness. Thanks to the high cooling rates of SLM, the crystalline phases in the gas-atomized powder almost completely disappeared and nearly fully amorphous structure parts were obtained after SLM processing. By choosing appropriate parameters, the size and quantity of the pores were reduced effectively and the relative density of the samples can reach values of over 96%. Although additional work is required to remove the residual porosity and avoid the formation of cracks during processing, the present results contribute to the development of Fe-based bulk metallic glasses parts with complex geometry via the SLM.”

(a) SEM secondary electron image of the gas-atomized powder; (b) SEM back-scattered image of the cross-section of the powder.

Fe-based BMGs are important for their unique combination of high physical, chemical, and mechanical properties, low affinity towards oxygen, and the fact that the raw material is less expensive than other commercial BMGs. So the researchers used a Fe-based metallic system Fe-Cr-Mn-Mo-W-B-C-Si with large glass forming ability (GFA) for the study, and used X-Ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC) to investigate structural variations between the original powder and the SLM 3D printer parts.

Samples prepared with different laser energy density.

According to the powder’s morphology, the surfaces are very smooth, which results in good flowability. But, the team also observed that micro-pores were formed by trapped glass, and that crystallization did occur in a small amount of the powder, due to the fact that, as the researchers explained, “the cooling rate during gas atomization is not high enough to suppress crystallization.”

However, the crystalline phases in the gas-atomized powder disappeared after SLM 3D printing.

Samples were 3D printed with different laser energy densities, in order to investigate the metallic glasses’ mechanical properties and microstructural evolution. By choosing the appropriate parameters, the researchers were able to successfully 3D print high quality Fe-based metallic glasses.

“At present it is great challenge to produce large-scale glassy alloys in sophisticated geometries with the existing technologies. SLM technology, including heating the powder to melting in very short time and then the melting pool rapidly solidifying procedures, provides new opportunities for the creation of large, geometry freedom of metallic glass components,” the researchers explained. “From the results above, we noticed that although the as-received powder had partially crystallized, the powder experienced a quickly laser processing procedure with high cooling rates, leading to nearly fully amorphous structure. This phenomenon proves that under optimized SLM processing conditions, the nucleation and crystallization are inhibited, and amorphous structure can be acquired.”

They also noted that to improve the quality of the SLM 3D printed parts by decreasing micro-cracks and pores, further fine-tuning of the processing parameters is necessary.

A selection of the as-built parts.

The researchers concluded, “In addition, the preparation process of the powder system still needs to be optimized, and ensuring a fully amorphous structure powders can be obtained which eliminates crystallization in the SLM parts. The present results confirm that additive manufacturing by SLM represents an alternative processing method for the preparation of bulk metallic glass components without limitations in size and intricacy. The processing method and conditions are in principle available for a large variety of metallic glasses production.”

Co-authors of the paper include X.D. Nong, X.L. Zhou, and Y.X. Ren with the university’s State Key Laboratory for Advanced Metals and Materials.

Discuss this story and other 3D printing topics at 3DPrintBoard.com or share your thoughts below.