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Three-dimensional printing is a useful and common process in additive manufacturing nowadays. The advantage of additive polymer technology is its rapidity and design freedom. Polymer materials’ mechanical properties depend on the process parameters and the chemical composition of the polymer used. Mechanical properties are very important in product applicability. The mechanical properties of polymers can be enhanced by heat treatment. Additive-manufactured PLA’s mechanical properties and structure can be modified via heat treatment after the 3D printing process. The goal of this research was to test the effect of heat treatment on the mechanical and structural parameters of additive-manufactured PLA. This was achieved via the FDM processing of standard PLA tensile test specimens with longitudinal and vertical printing orientations. After printing, the test specimens were heat-treated at 55 °C, 65 °C and 80 °C for 5 h and after being held at 20 °C for 15 h. The printed and heat-treated specimens were tested using tensile tests and microscopy. Based on the test results, we can conclude that the optimal heat treatment process temperature was 65 °C for 5 h. Under the heat treatment, the test specimens did not show any deformation, the tensile strength increased by 35% and the porosity of the PLA structure decreased.

We introduce a simple model for equity index derivatives. The model generalizes well known L\`evy Normal Tempered Stable processes (e.g. NIG and VG) with time dependent parameters. It accurately fits Equity index implied volatility surfaces in the whole time range of quoted instruments, including small time horizon (few days) and long time horizon options (years). We prove that the model is an Additive process that is constructed using an Additive subordinator. This allows us to use classical L\`evy-type pricing techniques. We discuss the calibration issues in detail and we show that, in terms of mean squared error, calibration is on average two orders of magnitude better than both L\`evy processes and Self-similar alternatives. We show that even if the model loses the classical stationarity property of L\`evy processes, it presents interesting scaling properties for the calibrated parameters.

The last two decades have seen enormous gains in industrial adoption of additive manufacturing (AM) technologies. Its layer-wise approach to fabrication offers designers the opportunity to create structures with unique performance advantages over their traditionally manufactured counterparts, and have created new manufacturing business models and supply chains. While today’s AM technologies have enabled the creation of new geometries, future AM systems that offer simultaneous processing of multiple materials in a single build open opportunities for new product functionality that cannot be achieved by traditional manufacturing methods. Advances in multi-material additive manufacturing, which integrate dissimilar material into a complex, three-dimensional object, is emerging but the advances have been sporadic. Moving beyond homogenous materials, adding multi-materials, gradient, functional and responsive materials, and materials with heterogeneous and graded properties means that a single additive process based on either energy delivery or material deposition alone may not be suitable. This perspective gives a brief overview of the current status, challenges, and future recommendations for multi-material additive manufacturing. The authors aim to expand the notion of multi-material additive manufacturing beyond combining materials with dissimilar properties, to combinations of materials at different length scales, material classes as well as multiple functionalities.

The deep penetration mode at selective laser melting of a metal powder layer is determined by a special and intense hydrodynamic process in a thin molten layer at rapid heating of the metal by usin...

Powder-binder jetting is an additive process with applications for manufacturing complex geometric structures, such as lightweighting, mold making, and in situ resource utilization (ISRU) for space...

In this paper, the consensus problem is investigated for discrete-time multi-agent systems with additive process noises. Due to the presence of additive noises in the system dynamics, consensus cannot be achieved. The main contribution of this paper is to give the exact consensus error. In particular, control gain depending on the agent dynamics and network topology is designed based on the technique dealing with the simultaneous stabilization. Finally, a numerical simulation is provided to demonstrate the effectiveness of the proposed theoretical results.

Cu-11Ni-6Sn alloy used bearing material in aerospace and mining industries, Casting is one of the famous metal additive process in which it is able to produce complex shape for engineering applications. Heat Treatment is the controlled heating and cooling of metals to modify their physical and mechanical properties. In the present study, to investigate the microstructural and wear behaviour of heat treated Cu-11Ni-6Sn alloys. During the aging process, the hardness of the alloy increased, which is due to microstructural changes. The wear rate is a function of hardness of the alloy decreased and it follows the adhesion theory of wear.

El objetivo de este trabajo es encontrar el modelo que brinde la mejor estimación posible del Valor Razonable de las partidas que componen los estados financieros, considerando la ambigüedad en la normatividad sobre el cálculo del mismo. Para ello se compararon tres metodologías: Flujos de Efectivo Descontados, Opciones Reales bajo los procesos Browniano Geométrico (MBG) y Browniano Aritmético (MBA). A pesar de que son muy pocos los estudios que han realizado este tipo de investigación, se ha llegado a la conclusión de que resulta más adecuado modelar un proceso aditivo como un MBA. Por dicha razón, se proyectaron los ingresos y posteriormente el flujo de efectivo anual de 2019 a 2028, posteriormente, se calcularon las Opciones Reales incorporando la flexibilidad de expansión y contracción de forma conjunta. De conformidad con los resultados obtenidos y en concordancia con lo sugerido por diferentes autores, el modelo que brinda la mejor aproximación posible del Valor Razonable es el de Opciones Reales bajo un MBG, con lo cual se recomienda que las empresas mexicanas conozcan y apliquen este modelo, complementando la valuación tradicional de flujos de efectivos descontados con el propósito de presentar información relevante para la toma de decisiones. La limitante más relevante que se presentó en la realización de esta investigación fue la carencia de la información financiera completa de todas las empresas seleccionadas inicialmente para con ello poder contrastar los modelos en comento y poseer una muestra de mayor tamaño.

The paper describes problems with the current additive manufacturing chain before considering additive manufacturing as part of a modern manufacturing chain. Additive manufacturing can be used for near net-shape for finishing, for repair or for adding special features which cannot be made with traditional manufacturing. This paper describes how STEP-NC deals with these different scenarios in terms of accuracy, multi-material and variation of slice direction. The possibilities of multi-material objects also raises questions about the design of such objects and how these need to be handled by an advanced controller. The paper also describes non-planar slicing. Curved direction and cylindrical direction are shown to improve the accuracy of curved structure additive manufacturing. STEP-NC using boundary representation has better capability of depicting complex internal structures for additive processes. By using exact model of the final product represented by STEP-NC, the paper demonstrates improvements in data size reduction, slicing accuracy, and precise manipulation of internal structure.

An additively manufactured in-package flex sensor for accurate bending prediction of flexible phased arrays is introduced. The sensor design is thin, flexible and accurate and can be readily embedded within a flexible phased array/Flexible Hybrid Electronics(FHE) package. Additively manufactured flexible phased arrays can be easily integrated with this proposed sensor using an all additive process. A series of bending tests were performed to measure the accuracy of the bending prediction for a proof-of-concept phased array. Using the dataset collected, the sensor can achieve 90 % accuracy in predicting the bend radius in both directions over the phased array plane. Using a 29 GHz 15×15 element phased array model, results in an 1.04 dB average gain error per missclassification and only 0.071 dB error in total as compared to 10.2 dB average gain error when using a non-calibrated equally phased array. This approach could be easily expanded to include multiple bend axis for larger arrays and flexible packages allowing for the accurate detection of non-radial, irregular bends.

This study provides qualitative data on sensory compounds present in barrel aged U.S. corn-based whiskies (primarily bourbon) and their unaged counterparts. Whisky samples of commercial brands by Heaven Hill, Buffalo Trace, Maker’s Mark, and Nelson’s Greenbrier Distillery were tested by direct injection gas chromatography/mass spectrometry. Chromatograms of samples were analyzed against NIST mass spectra to develop and compare sensory compounds present in the whiskies analyzed. Results obtained from commercial whisky brands were used to build a baseline of sensory compounds present, providing a framework to show comparable compounds between the barrel aged whiskies and colorless, unaged whisky. Results show that barrel aging is an additive process in terms of total sensory compounds present and that sensory compounds resulting from barrel aging having longer retention times than those found in unaged whisky. Key words: Whiskey, barrel aging, GC/MS, bourbon.

A negyedik ipari forradalom rengeteg új technológiának adott lendítő erőt, hogy kinője magát általánosan használt ipari alkalmazássá, illetve, hogy általános társadalmi felhasználási rétegekben is megjelenjen. Az ilyen technológiák egyike az additív gyártástechnológia, melynek során térbeli tárgyakat készítenek újabb és újabb rétegek hozzáadásával. A cikkben az additív eljárás, mint gyártási technológia kerül elemzésre anyagszerkezeti szempontból. A tanulmány keretében hangsúlyt fektetünk a polimerekből létrehozott próbatestek különböző nyomtatási paramétereire. Kutatásunk célja a nyomtatott darabok vetemedésének, zsugorodásának szoftveres vizsgálata, az eredmények összehasonlítása, továbbá a nyomtatási paraméterek hatásának vizsgálata a termék jellemzőire.

An alcohol additive 1, 8-Octanediol (ODO) with a simple carbon chain structure was first introduced into the light-emitting layer (LEL) of solution-processed small molecule organic light-emitting diodes (OLEDs) in this work. We found a typical host material of CBP presented a micro-aggregation film state with low percent of ODO adding in the LEL. The corresponded solution-processed devices with the LEL of CBP and 4CzIPN were investigated. The reduced device turn-on voltage and improved efficiency was achieved with low percent addition of 2 wt% ODO in LEL. Moreover, in the atmosphere, the device with ODO additive showed alleviated device degradation compared to no additive device. These results demonstrate the micro-aggregated state of the host is helpful, which can be attributed to the better charge transfer ability. Significantly, this additive process was also applied to other devices with reduced device turn-on voltage and improved efficiency.

The objective of this chapter is to give additional insight into the inks which are being used for printing RFID antennas; their properties, how to apply them, their performance, benefits and drawbacks and future developments for these inks. In addition, some attention will be given to adhesives, which are necessary to bond the die or die strap to the antenna. Conductive inks have their place in the HF-RFID market, with proven performance in the field. But, the UHF-RFID market is a relatively new application for inks and, while much testing has been conducted, the technology is still in its infancy. Using conductive inks for printing RFID antennas has several benefits: printing is an additive process and generates much less waste than certain subtractive processes, investment in the technology is minimal (especially for companies that are already active in the printing industry), and inks are relatively environmentally friendly. Certain inks do contain solvents, but the quantities are limited and, if one chooses not to use solventcontaining inks, there are water-based and UV-curable inks available, which are environmentally friendly. One may think that the RF-performance of an ink is inferior to that of aluminum or copper, but experiments have proven that the opposite is true. Ink performance in RFID applications has been studied extensively and the general consensus is that inks perform as well as copper or aluminum.

54th CIRP Conference on Manufacturing Systems, CMS 2021, Athens, Greece, 22 Sep 2021 - 24 Sep 2021; Procedia CIRP 104, 1173-1178 (2021). doi:10.1016/j.procir.2021.11.197 special issue: "54th CIRP CMS 2021 - Towards Digitalized Manufacturing 4.0 / Edited by Dimitris Mourtzis", Published by Elsevier, Amsterdam [u.a.]

The electric motor components are manufactured through the additive process of fused filament fabrication in order to verify the functionality of the electric motor assembly. This process was chosen due to the advantages it confers: fast obtaining of components, low manufacturing costs, no tools required for processing or for moulds manufacturing. Through the fused filament fabrication process, parts with complex geometries, which cannot be obtained by classical machining, can be manufactured. Due to the above-mentioned advantages, this technology is extremely useful for the manufacture and testing of prototypes. The paper aims to manufacture components of a brushless electric motor in order to verify the assembling compatibility and manufacturing accuracy.

Laser melting deposition (LMD) is a promising way for the fabrication of complex reduced activation ferritic/martensitic (RAFM) steel components which provides an exceptional opportunity to improve the existing designs and move toward fabricating fine features and complex geometries with higher efficiencies. It is well known that if steel members are welded together, defects will be concentrated in the welded joint. We can control the scanning path of the laser to achieve a complex component molding, avoiding welding. Considering the LMD technology, the results of each layer of powder molding will affect the fineness of the final processed products, such as laser power, scanning speed, defocus and so on, which are all important factors affecting the products. We control the size of powder particle size as a variable to conduct a study on RAFM steel supplemented by LMD technology for the first time, and its microstructure and grain size were analyzed. In terms of mechanical properties, its hardness, Charpy impact, tensile strength and elongation were measured. The results show that compared with other processing processes including Selective Laser Melting (SLM), rolling, welding joints, the tensile strength of RAFM steel manufactured by laser coaxial powder feeding is up to 1057.75 MPa, and there are no pores and almost no defects when using small particle size powder. The microstructure of LMD RAFM steel contains a large amount of lath martensite and δ-ferrite, and some precipitates such as Mx, whose average grain size decreases with the increase of powder particle size (5–150 μm). In this study, the laser additive process was monitored by high-speed photography, and the average grain size of LMD RAFM steel was further analyzed, and a reasonable explanation of its mechanical properties was given.

Приведены результаты экспериментальных исследований литейной оснастки, полученной процессом 3D-печати по технологии послойного нанесения полимерной нити. Проанализировано влияние технологических параметров на качество изготавливаемых литейных моделей. Проведено технологическое обоснование эффективности производства оснастки для условий серийного производства литья., The results of experimental studies of foundry equipment obtained by the 3D printing process using the tech-nology of layer-by-layer application of polymer filament are presented. The influence of technological parameters on the quality of manufactured casting models is analyzed. The technological substantiation of the efficiency of production of tooling for the conditions of batch production of casting has been carried out.

This article presents a discussion of 3D printing technologies applicable for different types of antennas, both flexible and non-flexible, designed with the help of different kinds of materials. To develop accurate and useful products, 3D technology has come out as a very attractive method over conventional etching and chemical processes in developing complicated structures while maintaining the same performance with respect to the conventional ones. Thus, this article presents a systematic approach for designing and developing 3D printed antennas with the help of both flexible and non-flexible materials using state-of-the-art 3D printing technology. 3D printing technology is also termed as ‘additive manufacturing’ because the final product is made by adding on layers of material one on one in the additive process. This technology even allows the printing of multiple colors which further enhances 3D prototype printing delivering unimaginable products to the individual users

In this study, thick-wall products made of aluminum-magnesium alloy 5356 were produced by wire-feed electron beam additive technology. The wall-shaped samples were printed using two different types of a printing process. A three-point bending test method was chosen to characterize their mechanical properties. Analysis of samples after three-point bending test showed the distribution of cracks along the direction of applied loading. A decrease in porosity is observed with the increase in the amount of heat input. It is shown that high strength properties are typical for samples printed with a higher value of heat input.

The evolution of the printed and flexible electronics has attracted great interest from the academia and the industrial world as well. Due to the wide number of potential materials and emerging applications that may be exploited, laser printing has been studied both for scientific research and commercial purposes. In this context, this chapter discusses the fundamental theory supporting laser printing and specifically Laser-Induced Forward Transfer that is a direct non-contact and non-destructive laser printing technique in an aim to provide a complete overview of the printing mechanism and the jetting dynamics, while in the following paragraphs potential applications are also presented. Moreover, since Laser-Induced Forward Transfer is a technique that could be described as an additive process, in contrary to the subtractive processes such as laser sintering, part of this chapter is focused on the evolution of the technique towards additive manufacturing as well as industrialization activities that have risen in the last 5 years.

The Sato process associated with self decomposable laws at unit time is further generalized to an additive process with arbitrary innovation term structures. A second generalization to additive processes consistent with bilateral gamma marginal distributions is also made. The Sato process is a parametric special case of the two generailzations. This feature is exploited in defining calibration starting values. Calibration results are presented for 1255 days of daily data on SPY options. The deterministic innovation variance model makes a median improvement of 15% in root mean square error over the Sato process. The comparable value for the general additive process is 40%. The Sato process relative to the general additive process overprices negative moves and underprices positive ones. The underpricing of negative moves decreases with maturity. On the positive side the overpricing decreases with maturity. For negative moves the overpricing is larger for smaller moves, while for positive moves the underpricing is larger for the larger moves.

The cold spray technology is a relatively new additive process allowing for the deposition of metallic coatings on metallic substrates; the particles impacting on target surface at high velocity deform and bond together leading to the coating formation and grow-up. Although the impact phenomena have been studied by several scientists in the last decades, the actual bonding mechanism for cold spray particles is still a recent focus of research. Therefore, aiming to further investigate the intriguing phenomena governing the particle-substrate interaction in cold spray, both experimental and numerical studies were carried out in this research activity. Ballistic tests were performed by impacting a single lead particle (1.5 mm in diameter) on a lead substrate at different impact velocities through a light ballistic airgun. A high-frequency camera was used to observe the particle impact and measure impact and rebound velocities. A detailed 3D quarter symmetric numerical model was developed and impact simulations were performed. The comparison between the experimental results and the numerical outcomes in terms of particles and substrate deformations as well as particle rebound velocity allowed for the validation of the model. The validated numerical approach was used to study the thermo-mechanical regimes taking place on impact surface pointing out the rule of strain-temperature interaction in cold spray bonding. On these results, a temperature-based bonding hypothesis was proposed and an original bonding algorithm was implemented on the numerical model.

Multi-Material Additive Manufacturing (MMAM) is an emerging manufacturing approach that is gaining interest in architecture and construction as an expansion of Additive Manufacturing. Hereby, different materials or material properties are combined in a single additive process in order to create objects that are composed of multiple materials. Ultimately, this approach introduces a new way of manufacturing and building, where assembly is no longer a necessity in order to combine multiple materials. Moreover, different potentials can be derived from the use of MMAM. Leading towards components with heterogeneous material composition and a high degree of adaption towards structural, environmental, and design criteria. This work provides an overview of the current state of MMAM in architecture and construction. Different processes and materials which have been reported are discussed and potentials, which emerge through the use of MMAM are described using specific use-cases.