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The growing applications and constant miniaturization of electronic devices and of low‐temperature co‐fired ceramics (LTCC) in various fields, such as aviation, telecommunications, automotive, satellite communications, and military, have led to an increase in the demand for LTCC. Such prospects arise due to the continuous scaling down of components and high‐density interconnection in electronics packaging. This paper reports a technique for the transfer of high‐resolution microstructures from silicon substrates to LTCC. In this method, gold and copper patterns were formed by photolithography, electrodeposition, and residual layer stripping on silicon substrate. Lithography provides the opportunity to create and transfer complex patterns for use in several different applications and electroplating enables the use of pure metal for excellent electrical properties. The developed structures were transferred onto a top layer of LTCC tape using hot embossing. Then, the subsequent layers were stacked, laminated, and sintered. A resolution of 1.5 μm after free sintering and 4.5 μm after pressure‐assisted sintering was achieved. This distinctive method can be useful for several applications requiring high‐resolution and superior electrical properties. [ABSTRACT FROM AUTHOR]

The article is devoted to identifying the origins and regional features of the technology of high-relief coinage in the Kazan-Tatar jewelry tradition. The main source was the electronic database of Tatar jewelry from museum collections, collected within the framework of the academic project “Jewelry of the Turkic peoples of Eurasia: general and special” (Russian Foundation for Basic Research 2013–2014, No. 13-06-97056). The research was based on a systematic technical and stylistic analysis of traditional jewelry and a detailed synchronous-diachronic examination of Bulgar-Golden Horde and Tatar products with three-dimensional images. Reconstruction of technological techniques related to this type of artistic metal processing made it possible to identify specific features of the formation of decor. The manual method of obtaining a unique relief using punches with a figured striker predominated. The decorations are characterized by the following: two or three-level bas-relief, the absence of a “locking” profile, the principle of “compositing” that underlies the conventionally interpreted floral and plant motifs, geometric orderliness, subject to the laws of the central-radial composition. The completed form of the decoration corresponds to the typical features of “notch chasing”, which is a marker of the Tatar craft tradition: smooth relief and “grain” background. An integrated approach allowed us to conclude that the origins of the existing artistic and figurative system can be traced in artifacts of the Bulgarian and Golden Horde silver of the 11th–14th centuries, made by embossing, stamping, and punching on a matrix. The formation of technological features was influenced by the traditions of high-relief coinage, which received regional development among Kazan silversmiths in the 17th–18th centuries. The specifics of Tatar relief coinage as a whole were formed in the context of Islamic art.

Tissue paper is deep-rooted in our daily life because of its different types of products that allow various applications. Tissue paper is a low grammage paper that is mainly characterized by softness, tensile strength, liquid absorption, and elasticity. These characteristics are essential when producing products such as toilet paper, kitchen rolls, hand towels, napkins, and facials. The tissue paper production involves two stages: formation of the tissue paper sheet itself and its converting into different finished products. Converting is characterized by several operations, namely: unwinding, winding, embossing, lamination, perforation, cutting, packaging, and palletizing. The most impacting operation is the embossing, which consists of marking a pattern on the paper sheet by applying pressure, with the intent to produce papers more aesthetically pleasing to the final consumer and/or a way to identify a particular brand. Also, it affects final properties, increasing the liquid absorption capacity and bulk but reducing softness and tensile strength. Converting is complex and has a huge impact on the finished products properties. In this review, the authors explored the different steps of converting and how they impact the different properties of finished tissue products.

The requirements for embossing of cardboard for print and packaging applications are constantly increasing. High degrees of forming, richness of detail, and high shape accuracy are desired. However, current embossing technology can only fulfil these requirements to a limited extent. A loss of detail and moderate degrees of forming are typical defects in the embossing process. In previous research work, a positive effect on the forming behavior of cardboard could be observed by the application of ultrasound. Therefore, the influence of ultrasound was also investigated for embossing. In order to quantify the effects of ultrasound, conventional and ultrasonic-assisted embossing results were compared. New approaches for analysis and evaluation of embossing results and new characteristic values for describing the forming were applied for the comparison. Two exemplary embossing geometries and a range of ultrasonic parameters were used to characterize the impact of ultrasound and showed positive effects to the forming results.

The Bayanovo burial ground dating from the IX – first half of the X centuries is one of the most interesting medieval sites of Perm Cis-Urals . At the moment it is the most studied burial site of Lomovatovo archaeological culture (527 burials have been studied). The article deals with the results of the study of wooden scabbards with metal plates found during the excavation of the monument. Based on the collection, visual analysis of sources and their study with the help of different natural scientific methods, a detailed view of the design of items, the features of their manufacture and decoration techniques are given. The authors found out that birch was the main material for making the base of the scabbard. Birch, leather and textiles were also used. Thin sheets of pure copper or sheets of an alloy with a high silver content were used to make the metal plates of the scabbard. The decoration of the items was carried out with the help of various jewelry techniques. Often the artifacts were decorated with stamped wire with a grainy effect, triangles made of grains, incrustation or squeezed ornithomorphic and anthropomorphic images. Gilding applied with the help of amalgamation was also used.

Tissue paper is deep-rooted in our daily life because of its different types of products that allow various applications. Tissue paper is a low grammage paper that is mainly characterized by softness, tensile strength, liquid absorption, and elasticity. These characteristics are essential when producing products such as toilet paper, kitchen rolls, hand towels, napkins, and facials. The tissue paper production involves two stages: formation of the tissue paper sheet itself and its converting into different finished products. Converting is characterized by several operations, namely: unwinding, winding, embossing, lamination, perforation, cutting, packaging, and palletizing. The most impacting operation is the embossing, which consists of marking a pattern on the paper sheet by applying pressure, with the intent to produce papers more aesthetically pleasing to the final consumer and/or a way to identify a particular brand. Also, it affects final properties, increasing the liquid absorption capacity and bulk but reducing softness and tensile strength. Converting is complex and has a huge impact on the finished products properties. In this review, the authors explored the different steps of converting and how they impact the different properties of finished tissue products. [ABSTRACT FROM AUTHOR]

Ultrathin, lightweight, high-performance, low- cost, and energy-efficient loudspeakers that can be deployed over a wide area have become increasingly attractive to both traditional audio systems and emerging applications such as active noise control and immersive entertainment. In this article, a thin-film loudspeaker is proposed based on an active piezoelectric layer embossed with an array of microscale domes. Actuation of these freestanding domes contributes to excellent sound generation by the loudspeaker, for example, 86 dB sound pressure level at 30-cm distance with 25-V (rms) excitation at 10 kHz, regardless of the rigid surface on which it is bonded. The acoustic performance is further tunable by designing the dome dimensions. The proposed loudspeaker also exhibits high bandwidth, which extends its prospects into the ultrasonic range. The loudspeaker weighs only 2 g, is 120 μm thick and can be manufactured at low cost. These advantages make the proposed loudspeaker a promising candidate for ubiquitous applications in existing and emerging industrial and commercial scenarios. [ABSTRACT FROM AUTHOR]

In this study, the mechanical and thermal properties of poly(lactic acid) (PLA) blends with an addition of poly(ε–caprolactone) (PCL) and fumed silica (SiO2) were evaluated to research the possibility of their use as relief printing plates for embossing processes. PCL and nano-silica were added to the PLA matrix at different concentrations. Morphological, thermal and mechanical analyses were performed to determine the properties and possible functional characteristics of the studied blends. SEM micrographs showed that unmodified PLA/PCL blends exhibit a morphology typical of incompatible blends with clearly visible spherical domains of dispersed PCL in PLA. In particular, the results of the hardness tests showed that the selected blends have the optimal hardness (between 65 SH D and 75 SH D) for use in the embossing process. The tensile tests showed that the addition of nano-silica to neat PLA and to the PLA/PCL blends 50/50 and 60/40 improved the mechanical properties of the blends, especially stiffness and toughness. The DMA results showed that the addition of smaller amounts of SiO2 can contribute to an increase in storage modulus, which is due to good dispersion and distribution of SiO2 in the matrix. DSC analysis showed that the addition of PCL to PLA polymer increased the thermal stability of PLA and that the addition of nano-silica increased the degree of crystallinity of PLA. The TGA results showed that the addition of nano-silica improved the thermal degradation behavior of the studied blends, especially for blends modified with 3 wt% nano-silica. The results show that it is possible to optimize the mechanical and thermal properties of the blends with the aim of using them in the embossing process. [ABSTRACT FROM AUTHOR]

The requirements for embossing of cardboard for print and packaging applications are constantly increasing. High degrees of forming, richness of detail, and high shape accuracy are desired. However, current embossing technology can only fulfil these requirements to a limited extent. A loss of detail and moderate degrees of forming are typical defects in the embossing process. In previous research work, a positive effect on the forming behavior of cardboard could be observed by the application of ultrasound. Therefore, the influence of ultrasound was also investigated for embossing. In order to quantify the effects of ultrasound, conventional and ultrasonic-assisted embossing results were compared. New approaches for analysis and evaluation of embossing results and new characteristic values for describing the forming were applied for the comparison. Two exemplary embossing geometries and a range of ultrasonic parameters were used to characterize the impact of ultrasound and showed positive effects to the forming results. [ABSTRACT FROM AUTHOR]

The potential for site-specific, process-parameter control is an attribute of additive manufacturing (AM) that makes it highly attractive as a manufacturing process. The research interest in the functionally grading material properties of numerous AM processes has been high for years. However, one of the issues that slows developmental progress in this area is process planning. It is not uncommon for manual programming methods and bespoke solutions to be utilized for site-specific control efforts. This article presents the development of slicing software that contains a fully automated process planning approach for enabling through-thickness, process-parameter control for a range of AM processes. The technique includes the use of parent and child geometries for controlling the locations of site-specific parameters, which are overlayed onto unmodified toolpaths, i.e., a vector-based planning approach is used in which additional information, such as melt pool size for large-scale metal AM processes, is assigned to the vectors. This technique has the potential for macro- and micro-structural modifications to printed objects. A proof-of-principle experiment is highlighted in which this technique was used to generate dynamic bead geometries that were deposited to induce a novel surface embossing effect, and additional software examples are presented that highlight software support for more complex objects. [ABSTRACT FROM AUTHOR]

In this study, the mechanical and thermal properties of poly(lactic acid) (PLA) blends with an addition of poly(ε–caprolactone) (PCL) and fumed silica (SiO2) were evaluated to research the possibility of their use as relief printing plates for embossing processes. PCL and nano-silica were added to the PLA matrix at different concentrations. Morphological, thermal and mechanical analyses were performed to determine the properties and possible functional characteristics of the studied blends. SEM micrographs showed that unmodified PLA/PCL blends exhibit a morphology typical of incompatible blends with clearly visible spherical domains of dispersed PCL in PLA. In particular, the results of the hardness tests showed that the selected blends have the optimal hardness (between 65 SH D and 75 SH D) for use in the embossing process. The tensile tests showed that the addition of nano-silica to neat PLA and to the PLA/PCL blends 50/50 and 60/40 improved the mechanical properties of the blends, especially stiffness and toughness. The DMA results showed that the addition of smaller amounts of SiO2 can contribute to an increase in storage modulus, which is due to good dispersion and distribution of SiO2 in the matrix. DSC analysis showed that the addition of PCL to PLA polymer increased the thermal stability of PLA and that the addition of nano-silica increased the degree of crystallinity of PLA. The TGA results showed that the addition of nano-silica improved the thermal degradation behavior of the studied blends, especially for blends modified with 3 wt% nano-silica. The results show that it is possible to optimize the mechanical and thermal properties of the blends with the aim of using them in the embossing process.

Targeted magnetic flux guidance in the rotor cross section of rotational electrical machines is crucial for the machine's efficiency. Cutouts in the electrical steel sheets are integrated in the rotor sheets for magnetic flux guidance. These cutouts create thin structures in the rotor sheets which limit the maximum achievable rotational speed under centrifugal forces and the maximum energy density of the rotating electrical machine. In this paper, embossing-induced residual stress, employing the magneto-mechanical Villari effect, is studied as an innovative and alternative flux barrier design with negligible mechanical material deterioration. The overall objective is to replace cutouts by embossings, increasing the mechanical strength of the rotor. The identification of suitable embossing geometries, distributions and methodologies for the local introduction of residual stress is a major challenge. This paper examines finely distributed pyramidal embossings and their effect on the magnetic material behavior. The study is based on simulation and measurements of specimen with a single line of twenty embossing points performed with different punch forces. The magnetic material behavior is analyzed using neutron grating interferometry and a single sheet tester. Numerical examinations using finite element analysis and microhardness measurements provide a more detailed understanding of the interaction of residual stress distribution and magnetic material properties. The results reveal that residual stress induced by embossing affects magnetic material properties. Process parameters can be applied to adjust the magnetic material deterioration and the effect of magnetic flux guidance. [ABSTRACT FROM AUTHOR]

The potential for site-specific, process-parameter control is an attribute of additive manufacturing (AM) that makes it highly attractive as a manufacturing process. The research interest in the functionally grading material properties of numerous AM processes has been high for years. However, one of the issues that slows developmental progress in this area is process planning. It is not uncommon for manual programming methods and bespoke solutions to be utilized for site-specific control efforts. This article presents the development of slicing software that contains a fully automated process planning approach for enabling through-thickness, process-parameter control for a range of AM processes. The technique includes the use of parent and child geometries for controlling the locations of site-specific parameters, which are overlayed onto unmodified toolpaths, i.e., a vector-based planning approach is used in which additional information, such as melt pool size for large-scale metal AM processes, is assigned to the vectors. This technique has the potential for macro- and micro-structural modifications to printed objects. A proof-of-principle experiment is highlighted in which this technique was used to generate dynamic bead geometries that were deposited to induce a novel surface embossing effect, and additional software examples are presented that highlight software support for more complex objects.

Embossing is a commonly used design element on printed products and packaging. It enhances the product impression with optical and haptic effects. The material deformation during the embossing of cardboard is normally done using high mechanical pressure between two dies. The use of ultrasound in the embossing process leads to a noticeable reduction of the embossing pressure and a greater embossing precision. However, there is a noticeable heating of the cardboard during the ultrasonic-assisted embossing process. This work aimed to characterise the effects of heating and to understand the reasons for the greater precision with decreased force when ultrasound is used. Therefore, the effects of the thermal ultrasonic energy on the chemical composition and the morphological properties of the fibres were investigated. The findings showed that no noticeable changes occurred in the chemical composition or fibre geometry as a result of the embossing process with ultrasound. [ABSTRACT FROM AUTHOR]

The article is devoted to the identification and archaeological and ethnographic interpretation of technical and technological features of the Tatar jewelry art. Kazan was one of the largest jewelry centers in the Russian Empire, distinguished by the peculiarities of technical and technological and ornamental techniques of jewelry, formal and morphological content of jewelry. Tatar jewelers had a grip on almost all technological processes, but they acquired a special skill in the art of filigree and embossing. In historiography there was a belief that the so-called knobby filigree is “distinctive and unique appliances that have not received distribution in jewelry of other Nations” (Tatar encyclopedia, p. 468). However, recent research (RFFI, project № 13-06–97056) showed that it was common in the jewelry of some of the peoples of the European part of Eurasia since the 11th century. Analogues of Kazan Tatar lumpy filigree of the 18th – the first half of the 19th centuries were revealed for the first time in Russian (religious) and European (secular) traditions of jewelry art. Original kind Tatar coinage is the coinage identified by the researchers (F.H. Valeev) as a high-relief. On the products, which were made using this technique, presence (merger) of regional traditions characteristic of Tatar and Russian art have been revealed. Manifestations of syncretism, whoch are observed in a number of technologies of Tatar jewelry production, are probably due to the existence of numerous Russian jewelry centers in Kazan, the Kazan Volga region as a whole (usually in monasteries), including a large handicraft in the village of Rybnaya Sloboda.

During the embossing process, a fiber sandwich is compressed between embossing tools. The use of ultrasound causes a short-term increase in the material temperature in addition to causing plastic deformation. The combination of the material compression and an increase in material temperature leads to structural changes, which can be observed by the change in mechanical properties of the cardboard. This work investigated the influence of an ultrasonically induced temperature increase on the structural changes of cardboard. Using three-parameter combinations, different temperature levels were achieved with a material densification of less than 5%. Subsequently, the samples were subjected to selected physical and visual analyses to characterize the change in the fiber structure. With the increase of 124 °C material temperature there was a decrease of about 15% in the splitting resistance and 10% in the bending stiffness. [ABSTRACT FROM AUTHOR]

Developing research skills in budding engineers at the undergraduate level is a daunting task. Research thinking is an important skill that can be developed among students during their UG program, as it will lead to acquiring sound basics of the area of interest as well as develop innovating ideas. This will enhance the confidence of young engineers and their career opportunities. The proposed approach enables the student to undergo various phases listed as 1) Idea Generation 2) Defining Problem 3) Design of Procedures 4) Observation 5) Data analysis 6) Interpretation 7) Communication. Here we propose the objectives and the methodologies introduced for the systematic approach of finding a solution through the research process. The process involved is Identifying the research problem through the literature and market survey, devising a solution for the problem, building the prototype, and validating through standard tests. The proposed approach was followed under a well structured two-credit course called Research for Undergraduate(REU) planned for a selected group of students of Automation and Robotics program, which is highly inter-disciplinary. The research problem identified was the need for a low-cost solution for 3D printing on polyester fabric, a potential problem identified by many textile industries involved in the fabric printing process. Currently, the technology being used for fabric printing on polyester material is the Screen printing and Embossing methods with specific limitations. Also, the requirement was to incorporate the automation feature to print any computer-generated 3D models easily and in a flexible fashion by incorporating rapid prototyping technologies. The scope of research included the materials used for printing as well as building of the low-cost automated mechanism involving three-axis controls for laying of the material on the fabric. The standards for material testing were explored and were implemented for the selected polymer used for printing. Here, the methodologies introduced for the systematic approach of selection and testing of polymer used in printing, the building of automated printing mechanism prototype, and validating through standard tests are discussed. The performance of the developed prototype model of 3D printing mechanism is evaluated and analyzed. The mechanism was tested using two materials, namely, Silicone Rubber and the other Plastisol with puff ink for rated specifications, in terms of viscosity, flexibility, surface adhesion pressure, durability, dimensional stability, scratch resistance, and abrasion resistance.Liquid Plastisol with 30% puff ink yielded the optimum adhesion strength with better mechanical properties and good puffy appearance on polyester fabric. The mechanism to print liquid Plastisol is demonstrated by an X-Y plotter. A micropipette is placed as a liquid dispenser to lay the material in required design as per the NC codes generated from the SolidWorks software model. The control parameters are sent to the stepper motor drives through the Arduino controller to control the 3D mechanism. The proposed activity provided a lot of research insight into the design and development issues for both the students and the faculty coordinators. [ABSTRACT FROM AUTHOR]

This study provides an analysis of the hot embossing process with poly methyl methacrylate (PMMA) film. The hot embossing process engraves a fine pattern on a flexible film using a stamp, applied heat and pressure. As the quality of the embossing pattern varies according to various process variables, the mechanism of making the embossed shape is complicated and difficult to analyze. Therefore, analysis takes much time and cost because it usually has to perform a lot of experiments to find an appropriate process condition. In this paper, the hot embossing process was analyzed using a computational analysis method to quickly find the optimal process. To do this, we analyzed the embossing phenomenon using the finite element method (FEM) and arbitrary Lagrangian–Eulerian (ALE) re-mesh technique. For this purpose, we developed a constitutive model considering the strain, strain rate, temperature-dependent stress and softening of the flexible film. Work hardening, strain softening, and temperature-softening behavior of PMMA materials were well described by the proposed method. The developed constitutive model were applied in the embossing analysis via user-subroutine. This proposed method allowed a precise analysis of the phenomenon of film change during the hot embossing process.

Small-scale optical components with micron or submicron features have grown in popularity in recent years. High-quality, high-efficient, and cost-effective processing approaches for polymer optics mass production are an urgent need. In this study, ultrasonic vibration will be introduced in embossing. The major advantage is that the required energy can be provided for process times ranging from a few hundred milliseconds to a few seconds, and that the process energy is provided at exactly the required location so that the structures in the surrounding area are not affected. Due to the strong correlation between electrical impedance and the temperature of the material, a novel impedance-based control strategy has been utilized for precisely controlling ultrasonic vibration during the embossing process. The investigation used two types of stamps with grating line widths of 4 µm and 500 nm, respectively. As a result, an embossing time of less than a few seconds was accomplished and a uniform embossed surface with an average fill rate of more than 75% could be achieved.

Rejected tanned leather is tanned lether product with damages of more than 30% of its total surface area, but can be improved by embossing. Embossing is the provision of patterns that influences the properties of articles and contributes to the closure of the defects on the surface of leather. This study aims to determine the influence of urethane binder and embossing motives to the quality of rejected leather for shoe upper applications. Variables investigated were urethane binder composition (100, 150, and 200 part in 1000 part of base coat) and embossing motives (crocodile, ostrich, shark fish, and milled motive). The quality of the leather was then tested in terms of organoleptic properties (feel, flexibility, visual appearance), mechanical properties (tear strength, tensile strength, elongation at break, rub fastness (dry, wet), adhesive strength of cover paint (dry, wet), and flexing resistance), physical properties (WVP and WVA), as well as morphology (SEM). The results showed that the addition of urethane binder and embossing patterns affect the quality of shoe upper leather, i.e. in general covering the leather defects and increasing the visual appearance (organoleptic properties), and changing the collagen network structure (based on SEM test). Visually preferred skin is skin with the addition of 200 parts of the urethane binder and crocodile patterned leather.

This paper proposes a novel micro high-speed forming technique, laser shock liquid flexible embossing (LSLFE), that uses liquid shock wave induced by the laser energy to achieve elastic-plastic forming of parts, to emboss metallic foils into three-dimensional large area microarrays, and expand the range of liquid impact forming application to the field of microforming. In this study, the micro-die and liquid chamber are designed to investigate the effects of the workpiece thickness and laser energy on formability. Then, experiments are performed to demonstrate the deformation characteristics of pure copper foils with LSLFE process. The results show that the fabrication of microparts with microscale structures through LSLFE is feasible. The morphology and fitability of the formed part indicate that accurate shape and dimension replication can be achieved through this technique. Then, the influences of laser pulse energy and copper foil thickness on the deformation depth of the formed parts are investigated. The results show that the depth of the replicated features increases with laser energy rising and the workpiece thickness decreasing. Besides, surface quality investigations indicate that the roughness of the fabricated micro-die and the original workpiece, as well as the process method significantly influence surface quality of the formed parts. Nanoindentation tests show that the hardness of the formed parts along the cross-section increases in various degree after LSLFE. Finally, the thickness distributions are characterized by polishing the cross-section of the formed parts and the most significant necking of thickness occurs at the fillet location. [ABSTRACT FROM AUTHOR]

This study aimed to identify the performance properties that drive the shelf price of kitchen paper towels and evaluate whether sustainability is an important driver for pricing. Nineteen products were compared according to their performance (softness, absorbency, and strength), technology, and fiber morphology. Metrics to rank the products in different grades (economy, premium, and ultra) according to their performance were provided. A multiple linear regression showed that absorbency and softness are the most significant properties used to predict the price. Market data indicates that there is a segment of consumers willing to pay a premium price for products marketed as "sustainable", even though their performance is comparatively inferior to the majority of the samples. Sustainable products are up to 85% more expensive than regular products. The metrics obtained in this work can contribute to improvement in market transparency, and aid companies in deciding strategies for product development and new investments. [ABSTRACT FROM AUTHOR]

An imprinting process with a brass stamp is used to generate a step on polypropylene plates. Process parameters are systematically varied, temperature, pressing-time, -pressure and the resulting step-heights are determined. Combining the direct correlation of step-height with its variation as a function of process parameters reveals most desirable process parameters. The approach described can be applied to a wide range of processing challenges. [ABSTRACT FROM AUTHOR]

The goal of this study was to develop and test an appropriate method for the evaluation of surface quality and to identify and quantify the quality of a surface modified by 3D molding. New software was developed to evaluate the surface quality based on the identification of macroscopic defects such as cracks within a scanned area. The influence of specific factors that affect the development of cracks during the uneven pressing process was assessed. Based on the measured and evaluated results, a process combination of factors was designed which yielded an embossed surface that was formed with the lowest proportion of cracks and with sufficient shape stability. In this work, 432 groups of test pieces were monitored, with each piece exposed to different combination of factors. Based on the measured and evaluated results, we found a combination that provided the lowest crack ratio. This innovative method will contribute to the knowledge of embossed surface quality and to the improvement of the uneven pressing process for wood surfaces.

Microfabricated devices have been introduced as a promising approach to overcome some of the challenges related to oral administration of drugs and, thereby, improve their oral bioavailability. In this study, we fabricate biodegradable microcontainers with different polymers, namely poly-ɛ-caprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA) 50:50 and PLGA 75:25 by hot punching. The mucoadhesion of the microcontainers is assessed with an ex vivo retention model on porcine intestinal tissue. Finally, in vitro degradation studies of the biodegradable microcontainers are completed for six weeks in simulated intestinal medium with the addition of pancreatic enzymes. Through SEM inspection, the PLGA 50:50 microcontainers show the first signs of degradation already after two weeks and complete degradation within four weeks, while the other polymers slowly degrade in the medium over several weeks.

Pattern formation of pyrolyzed carbon (PyC) and tetrahedral amorphous carbon (ta-C) thin films were investigated at micro- and nanoscale. Micro- and nanopillars were fabricated from both materials, and their biocompatibility was studied with cell viability tests. Carbon materials are known to be very challenging to pattern. Here we demonstrate two approaches to create biocompatible carbon features. The microtopographies were 2 μ m or 20 μ m pillars (1:1 aspect ratio) with three different pillar layouts (square-grid, hexa-grid, or random-grid orientation). The nanoscale topography consisted of random nanopillars fabricated by maskless anisotropic etching. The PyC structures were fabricated with photolithography and embossing techniques in SU-8 photopolymer which was pyrolyzed in an inert atmosphere. The ta-C is a thin film coating, and the structures for it were fabricated on silicon substrates. Despite different fabrication methods, both materials were formed into comparable micro- and nanostructures. Mouse neural stem cells were cultured on the samples (without any coatings) and their viability was evaluated with colorimetric viability assay. All samples expressed good biocompatibility, but the topography has only a minor effect on viability. Two μ m pillars in ta-C shows increased cell count and aggregation compared to planar ta-C reference sample. The presented materials and fabrication techniques are well suited for applications that require carbon chemistry and benefit from large surface area and topography, such as electrophysiological and -chemical sensors for in vivo and in vitro measurements.

Weight reduction in structural design can be achieved using lightweight materials and functional integration. A new approach consists in the direct integration of piezo ceramic elements into micro structured aluminum sheets in order to act as sensors or actuators. Typical applications are structure health monitoring or active noise canceling. Thereby piezo ceramic rods are inserted into micro embossed channels. However, the necessary embossing process involves high compression stresses in the sample leading to increased friction, adhesive tool wear and failure. The goal of the research is a decrease of the forming force in the generation of micro channels. For that purpose, the tool and the samples are heated. In addition, the achievable precision and reproducibility should be similar to cold forming. Process parameters like stamp velocity, holding time and lubrication are varied and their influence on the formed channels is investigated. At a forming force of 80 kN, the deepest channels were obtained at the highest temperature applied, which amounts to 200 °C. Because of the thermal contraction of the aluminum samples during the cooling down process, structure dimensions are only significantly smaller compared to cold formed samples. The reproducibility of the forming process was demonstrated within an additional test series. [ABSTRACT FROM AUTHOR]

To improve wear properties and reduce friction in orthopedic bearings, UHMWPE surface texturing is a proposed approach to retain fluid, reduce stress in the polymer and promote lubrication in the joint. The objective of this study was to establish a preliminary procedure to texture UHMWPE specimens using a custom die in a hot embosser. Four parameters were varied in subsequent stages: hold pressure, chamber temperature, hold duration and specimen cooling. Each stage was based upon the successful results of the previous stage. A dimple diameter of 96% of the desired diameter was achieved. These parameters will be used to commence a formal procedure to optimize the process using a formal DOE method. [ABSTRACT FROM AUTHOR]

Folding is a process of forming cellular structures out of a flat raw material. Through this technology it is possible to create sharp-edged structures with high depths and multiple bending axes and for this reason it is part of the technical origami. Current research work at the IFU focuses on applying this technique to sheet metals with thicknesses between 0.5 – 2mm. These kinds of structures can be used for optically appealing claddings, heat exchangers or sandwich panel core materials. In previous projects, it was shown that it is necessary to pre-crease the bending axis on the flat raw material to achieve a defined folding process. For sheet metals, in particular the embossing of grooves is a promising approach. The general challenges for folding sheet metals are the forming of radii, the hardening effects emerging in the bending axis, and well-ordered design of appropriate tool concept. Also appropriate FEA models are necessary for a sufficient development of this process. The embossing of grooves itself is a bulk metal forming process and, therefore requires volume elements. Folding itself, however, is a forming process of large blanks, which is why simulations based on tetrahedral elements are extremely time-consuming. For this reason, two different models are necessary. The first model, which has integrated volume elements, simulates the folding of single folding cells targeting to detect the interaction of the embossing and the subsequent bending process. In the second model, shell elements are used, with a focus on the effect of the grooves’ run rather than the effects of the embossing itself. In this paper, a FEA model for the folding of a mono cell is presented, which shows that a defined folding with small radii for sheet metals with blank thicknesses larger than 0.5mm is possible as well. [ABSTRACT FROM AUTHOR]

Manufacturing of the embossing tools customary implies use of metals such as zinc, magnesium, copper, and brass. In the case of short run lengths, a conventional manufacturing process and the material itself represent a significant cost, not only in the terms of material costs and the need for using complex technological systems which are necessary for their production, but also in the terms of the production time. Alternatively, 3D printing can be used for manufacturing similar embossing tools with major savings in production time and costs. However, due to properties of materials used in the 3D printing technology, expected results of embossing by 3D printed tools cannot be identical to metal ones. This problem is emphasized in the case of long run lengths and high accuracy requirement for embossed elements. The objective of this paper is primarily focused on investigating the influence of the printing speed on reproduction quality of the embossing tools printed with FDM (Fused Deposition Modelling) technology. The obtained results confirmed that printing speed as a process parameter affects the reproduction quality of the embossing tools printed with FDM technology: in the case of deposition rate of 90 mm/s was noted the poorest dimensional accuracy in relation to the 3D model, which is more emphasised in case of circular and square elements. Elements printed with the highest printing speed have a greater dimensional accuracy, but with evident cracks on the surface. [ABSTRACT FROM AUTHOR]

In this communication, we report a physical method for the fabrication of organic solvent and surfactant-resistant barriers on paper-based fluidic devices. When nonwoven polypropylene sheet is embossed with a steel mold, the embossed region acts as a physical barrier that can prevent the flow of liquids. Embossed polypropylene barriers not only block water, but also block organic solvents and surfactants, which are known to be difficult to handle on previous paper-based devices. Various amounts of embossing pressures were tested to determine the minimum embossing pressure required for leakproof barrier formation. The compatibility of the barrier was also investigated with several surfactants and organic solvents. As a demonstration, a lysis buffer, which was known to leak through wax-printed barriers, was used to detect Escherichia coli (E. coli) O157:H7. To the best of our knowledge, this paper is the first to report a one-step fabrication method of paper-fluidic devices capable of handling surfactants and organic solvents, including alcohols. [ABSTRACT FROM AUTHOR]