Manufactura Aditiva de UAVs: Cómo aumentar la resistencia de las piezas mediante sandwichs de ABS y CFRP

Si existe una tendencia invariable en todo el proceso de diseño aeronáutico, ésta es mejorar el rendimiento de los aparatos haciéndolos más ligeros pero aumentando su resistencia mecánica al mismo tiempo.

Esa "cuadratura del círculo" puede lograrse mediante el uso de materiales compuestos CFRP. Los compuestos CFRP (Polimero Reforzado con Fibra de Carbono) son materiales livianos pero fuertes que suelen utilizarse en las aplicaciones más exigentes debido a sus excelentes propiedades mecánicas.

Un equipo colaborador de investigadores de la Universidad de Kingston, la Universidad de Liverpool y la Universidad de Ciencia y Tecnología de Khalifa han publicado un estudio titulado  “Additive Manufactured Sandwich Composite/ABS Parts for Unmanned Aerial Vehicle Applications" que analiza el uso de materiales compuestos CFRP en estructuras de sándwich, utilizando núcleos fabricados mediante Impresión 3D basada en tecnología FDM.

Las estructuras de sándwich ofrecen una resistencia y rigidez específicas superiores a las que ofrecen los compuestos monolíticos, y se fabrican agregando dos capas de piel delgada a un núcleo grueso y liviano. El material del núcleo es generalmente más barato, y tiene menor resistencia y densidad en comparación con las capas de la piel.

En cuanto a la tecnología FDM, si bien las piezas creadas mediante esta tecnología presentan con frecuencia una mayor anisotropía que las piezas fabricadas mediante otras tecnologías tales como SLS, SLM o EBM, resulta sin embargo la tecnología más equilibrada para muchas aplicaciones y más concretamente para fabricación de piezas de uso final en vehículos aéreos no tripulados (UAV, por sus siglas en inglés) donde se requiere peso ligero, resistencia mecánica, rigidez, economía de costes, versatilidad de materiales, economía de tiempo y agilidad de fabricación.

En este documento se propone un proceso de fabricación de la estructura del UAV utilizando para ello sandwichs de núcleos de ABS fabricados mediante FDM y recubiertos de CFRP,  al objeto de mejorar el módulo de elasticidad y la resistencia mecánica del ABS impreso.

Particularmente en el caso de los UAVs, las estructuras compuestas en sándwich presentan una doble ventaja: Conservan las ventajas de la tecnología FDM a la hora de fabricar geometrías complejas, y solo requieren simples pasos de post-procesamiento para mejorar las propiedades mecánicas de la pieza final.

Para la realización del estudio se utilizó una ANN (Red Neuronal Artificial) a fin de de investigar la influencia de la densidad del núcleo y el número de capas de CFRP en las propiedades mecánicas de la pieza final. El resultado mostró  una mejora de la resistencia específica y el módulo de elasticidad al aumentar el número de CFRP: La resistencia específica de las muestras mejoró de 20 a 145 KN*m / kg, mientras que el módulo de Young aumentó de 0,63 a 10,1 GPa al laminar las muestras con capas de CFRP. 

Stratasys Composite Production

Stratasys’ development of high-temperature materials, as well as the increased throughput of its Fortus 3D Production Systems, enable the manufacture of high-temperature lay-up / sacrificial tooling in hours or days, rather than the weeks or months it would take to produce and procure tooling made from traditional methods.

3D printed tooling also offers disruptive cost-savings compared to traditional tooling materials and numerous other less quantified benefits, such as dramatic weight savings. This is being exemplified by Dutch 3D service bureau, Visual First, who is using FDM Nylon 12CF carbon-filled thermoplastic to replace metal machine parts for its customer, The Chocolate Factory.

This has significantly reduced machine downtime, ensuring production line continuity for the company. In fact, the replacement time of broken machine parts has been reduced from one month to one week using Stratasys additive manufacturing compared to traditional handmade metal replacements, with cost reductions of 60%.

Application of 3D printing technology in aerodynamic study

3D printing, as an additive process, offers much more than traditional machining techniques in terms of achievable complexity of a model shape.

That fact was a motivation to adapt discussed technology as a method for creating objects purposed for aerodynamic testing.

The following paper provides an overview of various 3D printing techniques. Four models of a standard NACA 0018 aerofoil were manufactured in different materials and methods: MultiJet Modelling (MJM), Selective Laser Sintering (SLS) and Fused Deposition Modeling (FDM).

Various parameters of the models have been included in the analysis: surface roughness, strength, details quality, surface imperfections and irregularities as well as thermal properties.

Read more:

http://iopscience.iop.org/article/10.1088/1742-6596/530/1/012009/pdf

General Atomics looks for an Additive Manufacturing Machine Technician

Duties & Responsibilities

Follow established procedures, assembly documentation, work instructions, methods and sequence of operation related to the creation of production parts and tooling using Additive Manufacturing (AM) (3D Printing), FDM and SLS techniques.

Essential Functions

Setup, operate and perform daily maintenance on AM machines.

Desirable Qualifications

Background in FDM (Fused Deposition Modeling) and/or Selective Laser Sintering (SLS) AM technologies.

More info:

https://www.linkedin.com/jobs/view/additive-manufacturing-machine-technician-at-general-atomics-503569977/

¿Can 3D Printing get married with traditional technologies?

More and more, Additive Manufacturing is now seen as a complementary technology, as witnessed by the increased in hybrid printers that combine 3D Printing and CNC machining.

Now, Stratasys, one of the leading players in the 3D printing industry, is sharing some of that expertise via a new whitepaper titled "How Additive and Traditional Manufacturing Mix".

The whitepaper is free to download from 3dprint.com after you fill out a brief form, by clicking here: https://3dprint.com/stratasys-how-additive-and-traditional-manufacturing-mix/.

Introduction to Additive Manufacturing for Composites

Additively manufactured composites offer advantages that include greater design flexibility, decreased costs and production efficiency. In this e-book, you’ll learn more about:

• Reinforced thermoplastics for high-performance applications
• Multi-axis motion platforms for design optimization
• Lightweight, agile mold tooling capabilities
• Sacrificial tooling for easier production of hollow composites
• Autoclave cure- and high-temperature-capable materials

Download this FREE e-book to learn how additive manufacturing enables a new era of lightweight structures with degrees of geometric complexity, part consolidation, and design optimization not previously possible.

Low-cost approaches to UAV design using Additive Manufacturing

Unmanned Aerial Vehicle (UAV) platforms are of major interest to Defense, Government, and commercial industries. The ability to remotely control an aerial vehicle capable of surveillance, offensive and defensive maneuvering, reconnaissance, or numerous other applications without the need to put a human life in jeopardy is a major attraction to their use. Furthermore, there exists opportunities to make these airborne vehicles largely autonomous, further reducing the need for even remote human operators. However, for all of the significant advantages of UAVs, there is a significant negative: the cost of manufacture, and the cost of design. Due in part to the substantial amount of complex electronic equipment on board, UAVs become not only a design of aeronautics, but an experiment in energy conservation through optimization. A limited range of UAV power becomes a limiting factor of UAV application. The challenge becomes to optimize the size, weight, and aerodynamics of the UAV based on the application. 

(Read More)

FDM Lightweight Structures

The FDM process offers several material options, from ASA to Nylon 12 CF, each has attributes that make it suitable for a variety of lightweight structural applications. With this variety in materials, FDM technology is boosting design freedoms without having to sacrifice material use or part stiffness in both Aerospace and Automotive Industries. 

Download this white paper now and learn how to: 

    

•    Choose the correct material for each required application

•    Create higher strength-to-weight value by using use the “single bead” design methods 

•    Increase stiffness-to-weight ratio by using sparse fill in structural parts

http://aviationweek.com/knowledge-center/fdm-lightweight-structures

UAVs con electrónica embebida

¿Es posible fabricar un UAV mediante Impresión 3D... y que lleve embebida la electrónica? La respuesta es SÍ, SIN DUDA.

El reto lo ha protagonizado Phillip Keane, estudiante de la Universidad Tecnológica de Nanyang (Singapur), quien ha diseñado y fabricado un UAV con material Ultem 9085, utilizando para ello un sistema de producción 3D Fortus 450mc. Aunque se trataba sólo de un prototipo, el reto demostró la posibilidad de llevar a cabo una fabricación automatizada de UAVs complejos y funcionales mediante impresión 3D.

¿Looking for a 3D-Printable Racing Drone?

Yeggi is a search engine for printable 3D Models. They collect data from all 3D Communities and marketplaces offering 3D models to print, and give you the best results to find 3D models on the internet. ¿Are you looking for a 3D-Printable racing drone? here you have +2.700 printable 3D Models: Just click on the icons, download the file(s) and print them on your 3D printer

http://www.yeggi.com/q/racing+drone/?s=tt

Significant Aspects of the FAA’s Drone Rules

The Federal Aviation Administration has released its much anticipated Part 107 rules, which cover the use of drones for non-recreational purposes in the U.S. airspace system. The Part 107 rules are based on a document called the Notice of Proposed Rule-making (NPRM), which was released in February 2015. (Read more)

Airbus sees big growth in UAV market

Airbus Defence and Space believes the Unmanned Aerial Vehicle (UAV) market is poised for massive growth, and it is seeking to become involved in this sector, through technology like its Zephyr pseudo-satellite. (Read more)

Airbus presenta a THOR, su UAV impreso en 3D

THOR (Testing High-tech Objectives in Reality) es el UAV fabricado por Airbus a través de la impresión 3D.

Manufactura Aditiva para la fabricación de UAVs

"Manufactura Aditiva" es hoy día el término más comunmente aceptado en entornos profesionales para referirse al conjunto de tecnologías de fabricación basadas en la disposición sucesiva de capas de material.

Un conjunto de tecnologías en pleno desarrollo que está permitiendo obtener nuevos diseños de UAVs a unos costes y en unos plazos de tiempo imposibles de obtener mediante la manufactura tradicional. Vamos a ver en este post las tecnologías más significativas que existen a día de hoy.

A grandes rasgos, existen tres tecnologías que dominan el mercado:

FDM (Acrónimo de Fused Deposition Modeling o Modelado por Deposición de material Fundido)

SLA (Acronimo de Stereolitography o Estereolitografía)

SLS (Acrónimo de Selective Laser Sintering o Sinterizado Selectivo por Laser)

La tecnología FDM utiliza un cabezal de extrusión para depositar filamentos de plástico en estado de cuasi-fusion. Es la tecnología más extendida a escala mundial, y su rango de precios para aplicaciones profesionales empieza en torno a 15.000 Euros, pudiendo alcanzar hasta 300.000 en función de las capacidades de la máquina.

La tecnología SLA utiliza un láser UV para polimerizar en determinadas zonas una fina capa de un monomero fotosensible.

La tecnología SLS utiliza un láser infrarrojo para sinterizar en determinadas zonas una fina capa de polvo termoplástico.

Cada tecnología tiene sus propias ventajas y desventajas respecto de las otras, y elegir una u otra es el resultado de una ecuación que puede contener muchas variables: Para fabricar una sola pieza indudablemente la opción más económica será la FDM, pero si necesitamos fabricar grandes cantidades de piezas todos los días quizá sea mejor optar por la tecnología SLS. 

En lo referente a la libertad de diseño, es cierto que la Manufactura Aditiva permite obtener diseños imposibles de fabricar mediante las tecnicas de mecanizado tradicional. Pero existen algunas limitaciones a tener en cuenta. Por ejemplo, tanto la FDM como la SLA requieren el uso de estructuras de soporte para construir superficies por debajo de un angulo crítico relativo a la superficie de fabricación (normalmente 45º) y esas estructuras de soporte deben ser eliminadas tras la fabricación, lo cual requiere sumergir durante unas horas la pieza en un baño de disolución (caso de FDM) o someterla a otro tipo de procesos (caso de SLA).

Si optamos por la SLS no tendremos que esperar a que se disuelva el material de soporte pero necesitaremos eliminar a mano el polvo sobrante, además de que tendremos que esperar varias horas de enfriamiento antes de abrir el horno para retirar la pieza, ya que de lo contrario ésta podría sufrir deformaciones por el cambio brusco de temperatura.

Los materiales disponibles tambien difieren para cada proceso, aunque los fabricantes de UAVs optan preferentemente por el FDM ya que ofrece la posibilidad de trabajar con diferentes termoplásticos, entre los que se incluyen el ABS, el Policarbonato, el Nylon, la Polifenilsulfona y la Polieterimida, lo cual les proporciona un amplio abanico de aplicaciones que pueden ir desde el modelado conceptual y el prototipado funcional, hasta la fabricación digital directa de piezas aptas para uso final.

En particular, los materiales basados en Polieterimidas ofrecen una alta resistencia térmica y química, lo cual los convierte en los favoritos para la fabricación de piezas que deban resistir el contacto con el fuego.

Impresión 3D para desarrollo de UAVs: Aerialtronics

Vamos de nuevo a tratar acerca de la Fabricación Digital Directa de UAVs mediante la tecnología FDM.

Pero en este caso vamos a hacerlo de la mano de Aerialtronics, fabricante cuyos clientes están usando sus UAVs para tareas profesionales que abarcan desde la inspección de infraestructuras hasta la filmación de spots para TV.

Aerialtronics es una empresa pequeña (no más de 35 empleados) que se enfrenta desde sus inicios al reto de fabricar diseños personalizados para cada aplicación concreta: “Hemos desarrollado un concepto basado en una plataforma standard capaz de ser personalizada a gusto del cliente,” explica Joost Hezemans, diseñador jefe de Aerialtronics.

El producto en cuestión se denomina Altura Zenith, que permite diversas configuraciones en función de:

• Número y potencia de motores
• Capacidad de carga de pago
• Autonomía de vuelo
• Interfaces de usuario
• Gimbals
• Carcasas

"Personalizar cada UAV requiere llevar a cabo múltiples iteraciones que se traducen siempre a más dinero y más tiempo" dice Hezemans. “Esto convierte cada diseño en una ecuación complicada.”

En orden a reducir los ciclos de desarrollo y contener los costes, Aerialtronics decidió hace tiempo fabricar los modelos y prototipos mediante Impresión 3D, y más concretamente mediante una Impresora 3D Stratasys uPrint SE Plus.

Hezemans afirma que la decisión de recurrir a la Impresión 3D les ha permitido reducir drásticamente los plazos de entrega gracias a reducir su tiempo de I + D en un 50 por ciento.

"Nos gustó la facilidad de manejo de esta impresora 3D. Además, el material ABSplus ™ ofrece una relación resistencia/peso perfecta para construir un prototipo listo para volar."

New Stratasys 3D Manufacturing material

ASA (Acrylonitrile Styrene Acrylate) is an all-purpose thermoplastic 3D printing material used to produce prototypes, manufacturing tools and finished goods.

Owners of Stratasys 3D Production Systems in the UAV industry can now benefit from ASA's UV stability, strength and durability, as the company has introduced the new material to be used with its Fortus 360mc, Fortus 400mc and Fortus 900mc.

Stratasys Ltd. (Nasdaq:SSYS), headquartered in Minneapolis, Minnesota and Rehovot, Israel, is a leading global provider of 3D printing and additive manufacturing solutions. The company's patented FDM®, PolyJet™, and WDM™ 3D Printing technologies produce prototypes and manufactured goods directly from 3D CAD files or other 3D content.

Systems include 3D printers for idea development, prototyping and direct digital manufacturing. Stratasys subsidiaries include MakerBot and Solidscape, and the company operates a digital-manufacturing service, comprising RedEye, Harvest Technologies and Solid Concepts. Stratasys has more than 2500 employees, holds over 600 granted or pending additive manufacturing patents globally, and has received more than 25 awards for its technology and leadership.

AirDog: The first 3D-printed action sports UAV

Aimed primarily at the consumer market, AirDog is an innovative, yet simple-to-use, ‘quad-copter’ that operates via a wrist-worn tracking device and accommodates a standard GoPro sports camera.

“Airdog is a perfect example of how 3D printing is an enabler for inventors looking to turn their ideas into fully-operational parts quickly and effectively,” said Andy Middleton, Senior Vice President and General Manager EMEA at Stratasys. “In this case, both our core 3D printing technologies have proved instrumental in producing a fully-functional drone and wrist device. With the exception of the advanced sensor technology, both parts have been created entirely using 3D printing.”

“AirDog not only grants end-users their own affordable and personal aerial video crew, but goes one step further in providing thrilling footage from distances and angles previously inaccessible to such consumers,” said Edgars Rozentals, Co-founder and CEO of the Latvia-based, Helico Aerospace Industries. Helico is specifically targeting the outdoor ‘extreme’ sports market and expects AirDog to be of particular interest to recreational participants of freestyle BMX, motocross and skateboarding, as well as water-sports such as surfing, kite-surfing and wake-boarding.

Prior to investigating the use of 3D printed parts, Rozentals was trying silicon-molded designs through a supplier in China. But finally “The benefits delivered by 3D printing compared to the method we trialled originally are numerous,” said Rozentals. “Above all, turnaround time is significantly reduced and if we need to make last minute changes to a design, we can do so within a matter of hours, easily and cost-effectively. This was simply unachievable before as it necessitated time-consuming production of a costly new mold. In fact, I’m not sure how we would have arrived at the stage of having a functional part, were it not for Stratasys 3D printing technology. I founded the company two years ago and we’re a staff of three, so for start-ups like Helico, this technology isn’t just a game-changer, but the ticket to the game itself,” he said.

The company sought the expertise of Stratasys’ Latvian partner, Baltic3D, who also worked with Polish reseller Bibus Menos to meet the requirements outlined by Helico’s team. The final AirDog drone was fully 3D printed using Stratasys’ FDM-based ULTEM material, chosen for its ability to provide parts of extreme strength and durability, with the lightweight characteristics vital for take-off and in-flight manoeuvrability. “We were particularly impressed by how far we could push the boundaries of the ULTEM material,” added Rozentals. “The material’s functional stability enabled us to print very thin walls that further reduced AirDog’s overall weight.” To produce fully-functional parts that could perform in the real environment, both Stratasys’ FDM and PolyJet 3D printing technologies were used for AirDog and its AirLeash tracking device, respectively.

FDM makes custom parts for UAVs

In the growing unmanned vehicle market there is increasing demand for technologies that reduce time-to-market and lower development costs.

Until recently, most of UAV OEMs had been using various production techniques, such as CNC milling, mainly in the production of the aluminum core of its products.

This had become problematic on three levels:

•First, costs to produce increasingly complex and sophisticated parts were rising exponentially using traditional processes, such as CNC machining.

•Second, there was a critical dependency on sub-suppliers of CNC milled parts which tended to prioritize high volume contracts giving smaller orders a slower turn around.

•Third, some parts must be custom, meaning the company was producing even lower volumes with resultant increased cost for these parts.

To solve these issues, many UAV design engineers are reviewing various alternative technologies for more efficient production combining traditional production methods with modern in-house production techniques such as Fused Deposition Modeling (FDM), that allows delivering of custom parts just in hours or days.

Replacing expensive and lead-time critical CNC-milled parts with in-house manufactured plastic parts, engineers are reducing the part cost to one third. Also, the plastic parts perform better technically, weighing less and providing better electrical insulation.

MQ-9 Reaper 3D-Printed replicas at Sheppard AFB

The Trainer Development Flight (TDF) is a highly diversified group of civilians that work in different sections such as design, fabrication, assembly, quality/material/workload control and office support sections, as their core business is to provide top quality trainers in support of war fighting capability for the Air Force and DoD across the United States. 

The TDF has their own facility in the Sheppard Air Force Base (Wichita Falls, Texas) where they design, develop, and manufacture trainers and training aids for the Air Force and all branches of the Department of Defense (DoD) as required. These aids are used in numerous training environments, including avionics, weapons and fuel systems, medical readiness, HVAC, and telecommunications systems.

The trainers and training aids may be either original products or replicas of existing ones, depending on the training need. Some devices are not required to be working units, so it usually isn’t cost-efficient to purchase the actual device. For most training applications, it’s more economical to train students on replicas, instead of the often extremely expensive equipment.

The TDF uses direct digital manufacturing to fabricate a wide majority of its training products. To do so, it employs four FDM additive fabrication machines in a centralized location with AFSO 21 (Lean) processes incorporated into the overall process. The Fused Deposition Modeler creates 3D solid models directly from 3D CAD files, or similar software, using PC-ABS plastic to build strong durable, fully functional prototypes within hours.

Before adding direct digital manufacturing to its processes, the TDF used conventional manufacturing methods to make its products. Conventional manufacturing typically requires longer lead times because there is often multiple steps, such as machining, lathe work, welding, sheet metal bending and cutting. A similar difficulty occurs when producing tooling to mold a part. “Because most of our projects are either one-of-a-kind or very low volume, conventional methods become very expensive,” says Mitchell Weatherly, Chief of the TDF. “Only about 10 percent of our work is for prototyping, and 90 percent is production.”

The machine reduces cost of materials through use of PC-ABS plastic and reduction of wasted alloys. Before settling on FDM, the TDF considered “a multitude” of the other additive processes, says Weatherly. “With FDM, the investment is up front, not ongoing,” he says. “The parts are durable, and they have the high level of detail we require. In addition, the process is environmentally safe and 100% ‘green’ with zero waste.”

The TDF is responsible for designing and manufacturing an exact replica of any required UAV (MQ-9 Reaper in this case) for training repair technicians. It has built a variety of internal and external components using its FDM machines. Once the final product is complete the employees at the metal shop will cut the metal to the exact tolerance and add the metal for realism so that Airmen will know what the real product not only looks like, but can feel the actual physical weight of it. 

The components included most of the body components as well as several cowlings, propellers, and antennas. They also purchased a number of real UAV components from the OEM.“Major advantages to the FDM system include its speed over other processes or alternative build methods, the versatility of FDM versus injection molding, and the ability to run multiple parts simultaneously through the system,” says Weatherly. Benefits include ease of maintenance, as well as the availability to use multiple materials for a variety of purposes.

“Additional capabilities include the ability to design based on function needs instead of manufacturing constraints, and the ability to implement design changes immediately and at minimal costs. The versatility to manufacture any item coupled with zero hazardous waste is one of the greatest advantages to the Air Force,” says Weatherly. ”The FDM-based machines have been used for a number of trainer projects which have tight budgets. We have also utilized the FDM process for research and development for our airmen and soldiers to be able to train like we fight."

“For our first FDM machine purchase, we projected ROI in 4 years, but it took only 18 months,” Weatherly says. “For our second FDM machine purchase we saw ROI in only 9 months. You will never get away from conventional methods and highly skilled technicians, but you can give them the proper tools and new technology that can make their job easier and competitive. I believe FDM is one of the technologically advanced premier manufacturing methods available. Since 2004, when we purchased our first of four machines, the FDM process has saved the government over $3.8 million to date with an expected 10-to-15-year savings of over $15 million. “ 

Revolutionary “Smart Wing” Created for UAV Model Demonstrates Groundbreaking Technology

Stratasys and Optomec Inc. announced that the companies successfully completed a joint development project to merge 3D printing and printed electronics to create the world’s first fully printed electro-mechanical structure.

The development of a “smart wing” for an Unmanned Aerial Vehicle (UAV) model with functional electronics is a revolutionary event that has the potential to change product development in industries including medical device, consumer electronics, automotive and aerospace. An Optomec Aerosol Jet system was used to print a conformal sensor, antenna and circuitry directly onto the wing of a UAV model. The wing itself was 3D printed with the Stratasys Fused Deposition Modeling (FDM) process. The electrical and sensor designs were provided by Aurora Flight Sciences, a supplier of UAVs. The combination of FDM 3D printing and printed electronics technologies can provide benefits over traditional prototyping, manufacturing and field repair processes. Performance and functionality of products can be improved in two ways: 3D printers enable lighter weight mechanical structures; and conformal electronics printed directly onto the structure frees up space for additional payload. In turn, the process has a positive impact on the environment by using fewer materials. Manufacturers can implement this technology in a multitude of applications, not just in aerospace. This technology can benefit numerous industries by allowing thinner, lighter, fully functional structures that cost less to manufacture.