Micro-manufacturing : research, technology outcomes and development issues

Besides continuing effort in developing MEMS-based manufacturing techniques, latest effort in Micro-manufacturing is also in Non-MEMS-based manufacturing. Research and technological development (RTD) in this field is encouraged by the increased demand on micro-components as well as promised development in the scaling down of the traditional macro-manufacturing processes for micro-length-scale manufacturing. This paper highlights some EU funded research activities in micro/nano-manufacturing, and gives examples of the latest development in micro-manufacturing methods/techniques, process chains, hybrid-processes, manufacturing equipment and supporting technologies/device, etc., which is followed by a summary of the achievements of the EU MASMICRO project. Finally, concluding remarks are given, which raise several issues concerning further development in micro-manufacturing

The potential of additive manufacturing in the smart factory industrial 4.0: A review

Additive manufacturing (AM) or three-dimensional (3D) printing has introduced a novel production method in design, manufacturing, and distribution to end-users. This technology has provided great freedom in design for creating complex components, highly customizable products, and efficient waste minimization. The last industrial revolution, namely industry 4.0, employs the integration of smart manufacturing systems and developed information technologies. Accordingly, AM plays a principal role in industry 4.0 thanks to numerous benefits, such as time and material saving, rapid prototyping, high efficiency, and decentralized production methods. This review paper is to organize a comprehensive study on AM technology and present the latest achievements and industrial applications. Besides that, this paper investigates the sustainability dimensions of the AM process and the added values in economic, social, and environment sections. Finally, the paper concludes by pointing out the future trend of AM in technology, applications, and materials aspects that have the potential to come up with new ideas for the future of AM explorations

Effects of Gravity and Non-Perpendicularity during Powder-Fed Directed Energy Deposition of Ni-Based Alloy 718 through Two Types of Coaxial Nozzle

The consequences of gravity and the nozzle inclination angle in the powder-fed Directed Energy Deposition (DED) process were examined in this study. We also sought to define guidelines and manufacturing strategies, depending on the DED system configuration and the nozzle type. To do so, two nozzle types were used: a continuous coaxial nozzle with a slit of 0.5 mm and a four-stream discrete coaxial nozzle. Although the main effects of the configurations and the nozzles are well-known, their effects on the clad characteristics and the deposition strategy are as yet unclear. In this paper, measurements of a single clad and the effects of different deposition strategies on cladding applications and inclined walls are presented, and the consequences for manufacturing processes are discussed. Based on a complete study of a single clad, working vertically, five different tilted deposition strategies were applied: three to a single clad and two to an inclined wall. The results for both the single clad and the inclined wall reflect a pattern of changes to height, width, area, and efficiency, at both small and large nozzle angles and deposition strategies. The inclined wall presents a maximum horizontal displacement that can be reached per layer, without geometrical distortions. The amount of material per layer has to be adapted to this limitation.This research was funded by the European Commission through the project "PARADDISE: a Productive, Affordable and Reliable solution for large scale manufacturing of metallic components by combining laser-based Additive and Subtractive processes with high Efficiency” (Grant Agreement 723440), an initiative of the Public–Private Partnership “Photonics and Factories of the Future”. This research was also funded by European Institute of Innovation & Technology (EIT), through the project "DEDALUS: Directed Energy Deposition machines with integrated process ALgorithms Under dedicated monitoring and control System” (ID 20094), and by the vice-counseling of technology, innovation and competitiveness of the Basque Government (Eusko Jaurlaritza), under the ELKARTEK Program, PROCODA project, grant number KK-2019/00004

Vibration Assisted Robotic Hot-Wire Gas Tungsten Arc Welding (GTAW) for Additive Manufacturing of Large Metallic Parts

Most of the metal additive manufacturing technologies are focused on high cost and high end applications. There is in need, a low cost additive manufacturing technology suitable for low and high end metallic applications. Robotic automated welding can be considered as an alternative to manufactured large scale metal parts with layer by layer approach. However, many obstacles have to be overcome to make it viable technology in additive manufacturing industry. A Robotic hot-wire Gas Tungsten Arc Welding (GTAW) with low frequency vibrating filler wire has been used to deposit a metallic alloy. Different trials of weld-on-bead experiments were performed to obtain the desired envelop of the melt pool shape for build parts with low manufacturing costs and low build times.Mechanical Engineerin

Process Planning for Solid Freeform Fabrication Based on Laser-Additive Multi-axis Deposition

This paper describes a new approach for rapid prototyping based on volumetric skeletonization. Contrary to most of the popular techniques for Solid Freeform Fabrication (SSF) based on 2-1/2 -axis layering as planar slices, this approach suggests the growth of the component along all three coordinate axes. While this approach offers many advantages in terms of the elimination of the support structures for the reduction of the staircase effects and the elimination of various post processes for the functional parts, this approach also offers challenges towards process planning. For various complicated shapes it may not be possible to generate the required shape using this approach; however, a hybrid approach which also incorporates the deposition by layers, may offer an optimum solution. Preliminary results are based on the successful laser-based additive deposition along multiple g-vectors. The material properties and the problems of possible porosities are still to be investigated. Advantages, process planning, applications, experimental results, and the challenges of this new method are the subject of this paper.This work was financially supported by THECB (Texas Higher Education Coordinating Board) Grants 003613-0022-1999 and 003613-0016-2001, NSF (National Science Foundation) Grants DMI-9732848 and DMI-9809198 and by the US Department of Education Grant P200A80806-98.Mechanical Engineerin

Freeform Fabrication of Ionomeric Polymer-Metal Composite Actuators

Ionomeric polymer-metal composite (IPMC) actuators are a type of soft electromechanically active material which offers large displacement, rapid motion with only ~1V stimulus. IPMC’s are entering commercial applications in toys (Ashley 2003) and biomedical devices (Soltanpour 2001; Shahinpoor 2002; Shahinpoor, Shahinpoor et al. 2003; Soltanpour and Shahinpoor 2003; Soltanpour and Shahinpoor 2004), but unfortunately they can only actuate by bending, limiting their utility. Freeform fabrication offers a possible means of producing IPMC with novel geometry and/or tightly integrated with mechanisms which can yield linear or more complex motion. We have developed materials and processes which allow us to freeform fabricate complete IPMC actuators and their fabrication substrate which will allow integration within other freeform fabricated devices. We have produced simple IPMC’s using our multiple material freeform fabrication system, and have demonstrated operation in air for more than 40 minutes and 256 bidirectional actuation cycles. The output stress scaled to input power is two orders of magnitude inferior to that of the best reported performance for devices produced in the traditional manner, but only slightly inferior to devices produced in a more similar manner. Possible explanations and paths to improvement are presented. Freeform fabrication of complete electroactive polymer actuators in unusual geometries, with tailored actuation behavior, and integrated with other freeform fabricated active components, will enable advances in biomedical device engineering, biologically inspired robotics, and other fields. This work constitutes the first demonstration of complete, functional, IPMC actuators produced entirely by freeform fabrication.Mechanical Engineerin

A New Robotic Spray Technology for Generative Manufacturing of Complex Concrete Structures Without Formwork

The robot-assisted manufacturing is introduced for many years in automated production areas, while the production of buildings still follows the traditional manual process. Using new possibilities of digital planning the construction industry demonstrated potential for the implementation of freeform architectures, which are only possible using expensive and only once usable formwork structures. This paper focuses on sprayed concrete technology for automated production processes to build up freeform concrete components. A study case of the production of a concrete wall by an industrial robot, equipped with a concrete spraying tool is presented in order to investigate the possibilities and tolerancing issues of this technique

3D Printing of Functional Materials: Surface Technology and Structural Optimization

There has been a surge in interest of 3D printing technology in the recent 5 years with respect to the equipment and materials, because this technology allows one to create sophisticated and customized parts in a manner that is more efficient regarding both material and time consumption. However, 3D printing has not yet become a mainstream technology within the established manufacturing routes. One primary factor accounting for this slow progress is the lack of a broad variety of 3D printable materials, resulting in limited functions of 3D printed parts. To bridge this gap, I present an integrated strategy to fabricate a variety of functional materials/devices through the post-printing surface modification and target-motivated structural topology. A reusable 3D printed filter was first demonstrated to remove metal ions from water. This filter was functionalized with a layer of bio-adsorbent grown on its surface using post-printing modification, and the capacity was improved through structural optimization. To further improve the working efficiency, a customized 3D all-in-one printable material system was employed, which uses only one 3D printing material, but can realize various functionalities through a post-printing process. This material system is applicable for all types of photo-polymerization based 3D printing routes, including DLP, SLA, polyjet and other emerging technologies. It has significantly extended the capacity of current 3D printing technology. The 3D printed structures were converted into useful devices with new functions or new structural metamaterials with novel properties, that are attributed to both their materials composition and structural design. For example, we have showcased the magnetically manipulated robot, strength-enhanced lattice materials with high effective strength, ultralight metal materials and mechanical-metamaterials. In this thesis, a new generation of initiator-integrated material system was also developed. Beyond being able to successfully 3D print functional devices/materials with desirable properties, I also demonstrated that this initiator-laden material can be utilized to locally repair the surface damage, allowing a self-healing ability. In general, the developed 3D printing process that incorporates surface modification and structural topology enables a new class of functional devices/materials to be produced, and opens a door for further research and development of an increasing variety of 3D printing applications. Through the work presented in this dissertation, I substantially build upon and further establish the strategy and material system for 3D printing functional devices/materials, keeping in mind components, design, engineering and application

Additive manufacturing:state of the art and potential for insect science

Additive Manufacturing has become an efficient tool to study insect-inspired biomimetic solutions. Indeed, it can build objects with intricate 3D-shapes and use materials with specific properties, such as soft materials. From biomaterials to biostructures or biosensors, Additive Manufacturing allows more possibilities in terms of design and functions. Reciprocally, insect-inspired technological solutions can be implemented to enhance Additive Manufacturing processes providing for example biocompatible structures that can successfully host living cells. We believe that, thanks to its continuous progress, Additive Manufacturing will play a growing role in the development of insect-inspired solutions.</p

Force Measurement Methods in Telerobotic Surgery: Implications for End-Effector Manufacture

Haptic feedback in telesurgical applications refers to the relaying of position and force information from a remote surgical site to the surgeon in real-time during a surgical procedure. This feedback, coupled with visual information via microscopic cameras, has the potential to provide the surgeon with additional ‘feel’ for the manipulations being performed at the instrument-biological tissue interface. This increased sensitivity has many associated benefits which include, but are not limited to; minimal tissue damage, reduced recuperation periods, and less patient trauma. The inclusion of haptic feedback leads to reduction in surgeon fatigue which contributes to enhanced performance during operation. Commercially available Minimally Invasive Robotic Surgical (MIRS) systems are being widely used, the best-known examples being from the daVinci® by Intuitive Surgical Inc. However, currently these systems do not possess force feedback capability which therefore restricts their use during many delicate and complex procedures. The ideal system would consist of a multi-degree-of-freedom framework which includes end-effector instruments with embedded force sensing included. A force sensing characterisation platform has been developed by this group which facilitates the evaluation of force sensing technologies. Surgical scissors have been chosen as the instrument and biological tissue phantom specimens have been used during testing. This test-bed provides accurate, repeatable measurements of the forces produced at the interface between the tissue and the scissor blades during cutting using conventional sensing technologies. The primary focus of this paper is to provide a review of the traditional and developing force sensing technologies with a view to establishing the most appropriate solution for this application. The impact that an appropriate sensing technology has on the manufacturability of the instrument end-effector is considered. Particular attention is given to the issues of embedding the force sensing transducer into the instrument tip