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The purpose of this study is to evaluate the 3D printability of a multimaterial, fully self-supporting auxetic structure. This will contribute to expanding the application of additive manufacturing (AM) to new products, such as automotive suspensions.

An experimental approach for sample fabrication on a multiextruder 3D printer and characterization by compression testing was conducted along with numerical simulations, which were used to support the design of different auxetic configurations for the jounce bumper.

The effect of stacking different auxetic cell modules was discussed, and the findings demonstrated that a one-piece printed structure has a better performance than one composed of multiple single modules stacked on top of each other.

The quality of the 3D printing process affected the performance of the final components and reproducibility of the results. Therefore, researchers are encouraged to further study component fabrication optimization to achieve a more reliable process.

This research work can help improve the manufacturing and functionality of a critical element of automotive suspension systems, such as the jounce bumper, which can efficiently reduce noise, vibration and harshness by absorbing impact energy.

In previous research, auxetic structures for the application of jounce bumpers have already been suggested. However, to the best of the authors’ knowledge, in this work, an AM approach was used for the first time to fabricate multimaterial auxetic structures, not only by co-printing a flexible thermoplastic polymer with a stiffer one but also by continuously extruding multilevel structures of auxetic cell modules.

The representation of Heterogeneous Object (HO) is divided into two categories: Data model (DM) and material evaluation paradigm (MEP). A hybrid methodology with geometry model and volumetric dataset to represent heterogeneous properties is proposed in this paper. Geometry model of an object can guarantee the accuracy of the final HO slices; and volumetric dataset lends the flexible manipulability and other advantages to HO representation. Two MEPs, namely distance field (DF) based and Fixed Reference Features & Active Grading Source(s) (FRF&AGS) are presented to facilitate the process of HO representation according to the designer)s input parameters. The DM can be modified interactively with users until the final satisfactory result is obtained. In this paper, a scheme of HO slicing is described. In this method, we utilize the slices contour of geometrical model as constraint to reconstruct the HO slices, which can theoretically achieve the same accuracy with the geometrical shape. Some examples of Heterogeneous object represented with our scheme are provided.

Most layer‐based rapid prototyping systems use polygonal models as input. In addition, the input polygonal models need to be manifold and water‐tight; otherwise the built objects may have defects or the building process may fail in some cases. This paper aims to present a regulation method of an arbitrarily complex polygonal model for rapid prototyping and manufacturing applications.

The method is based on a semi‐implicit representation of a solid model named the layered depth‐normal images (LDNI), which sparsely encodes the shape boundary of a polygonal model in three orthogonal directions. In the method, input polygonal models or parametric equations are first converted into LDNI models. A regulation operator based on the computed LDNI models is presented. A volume tiling technique is developed for very complex geometries and high accuracy requirements. From the processed LDNI model, an adaptive contouring method is presented to construct a cell representation that includes both uniform and octree cells. Finally, two‐manifold and water‐tight polygonal mesh surfaces are constructed from the cell representation.

The LDNI‐based mesh regulation operation can be robust due to its simplicity. The accuracy of the generated regulated models can be controlled by setting LDNI pixel width. Parallel computing techniques can be employed to accelerate the computation in the LDNI‐based method. Experimental results on various CAD models demonstrate the effectiveness and efficiency of our approach for complex geometries.

The input polygonal model is assumed to be closed in our method. The regulated polygonal model based on our method may have a big file size.

A novel mesh regulation method is presented in this paper. The method is suitable for rapid prototyping and manufacturing applications by achieving a balance between simplicity, robustness, accuracy, speed and scalability. This research contributes to the additive manufacturing development by providing a digital data preparation method and related tools.

It is a challenge to print a model with the size that is larger than the working volume of a three-dimensional (3D) printer. The purpose of this paper is to present a feasible approach to divide a large model into small printing parts to fit the volume of a printer and then assemble these parts into the final model.

The proposed approach is based on the skeletonization and the minima rule. The skeleton of a printing model is first extracted using the mesh contraction and the principal component analysis. The 3D model is then partitioned preliminarily into many smaller parts using the space sweep method and the minima rule. The preliminary partition is finally optimized using the greedy algorithm.

The skeleton of a 3D model can effectively represent a simplified version of the geometry of the 3D model. Using a model’s skeleton to partition the model is an efficient way. As it is generally desirable to have segmentations at concave creases and seams, the cutting position should be located in the concave region. The proposed approach can partition large models effectively to well retain the integrity of meaningful parts.

The proposed approach is new in the rapid prototyping field using the model skeletonization and the minima rule. Based on the authors’ knowledge, there is no method that concerns the integrity of meaningful parts for partitioning. The proposed method can achieve satisfactory results by the integrity of meaningful parts and assemblability for most 3D models.

Our article on a new approach to CAD/CAM in mechanical engineering has been written by Dr. Brian Walker who, after graduating from Queen's University Belfast, went on to research in the use of computer based control systems, leading to his Ph.D in 1968. Since 1959 he has been with Ferranti and is now head of software and services development, and Product Manager for Ferranti Cetec Graphics' systems for engineering applications.

The purpose of this paper is to design a lightweight tree-shaped internal support structure for fused deposition modeling (FDM) three-dimensional (3D) printed shell models.

A hybrid of an improved particle swarm optimization (PSO) and greedy strategy is proposed to address the topology optimization of the tree-shaped support structures, where the improved PSO is different from traditional PSO by integrating the best component of different particles into the global best particle. In addition, different from FEM-based methods, the growing of tree branches is based on a large set of FDM 3D printing experiments.

The proposed improved PSO and its combination with a greedy strategy is effective in reducing the volume of the tree-shaped support structures. Through comparison experiments, it is shown that the results of the proposed method outperform the results of recent works.

The proposed approach requires the derivation of the function of the yield length of a branch in terms of a set of critical parameters (printing speed, layer thickness, materials, etc.), which is to be used in growing the tree branches. This process requires a large number of printing experiments. To speed up this process, the users can print a dozen of branches on a single build platform. Thereafter, the users can always use the function for the fabrication of the 3D models.

The proposed approach is useful for the designers and manufacturers to save materials and printing time in fabricating the shell models using the FDM technique; although the target is to minimize the volume of internal support structures, it is also applicable to the exterior support structures, and it can be adapted to the design of the tree-shaped support structures for other AM techniques such as SLA and SLM.

The purpose of this paper is to understand the relationship between defect properties and the tool path used for generating additively manufactured parts. The correlation between processing strategy and porosity architecture is one of the key aspects for a precise understanding of defect formation and possibilities for defect reduction.

The authors present a new combined geometry, processing path and porosity analysis procedure based on the use of x-ray computed micro tomography image data and numerical control programming code. The procedure allows for a covisualisation of the track of the respective processing head with the three-dimensional microstructure data.

The presented method yields statistical results about defect distribution and morphologies introduced by the respective process characteristics in parts. The functionality of the proposed procedure is demonstrated on an aluminum (AlSi10Mg) and a polylactide test sample to show the additional insight found for both additive manufacturing processes and the resulting microstructural properties.

The novelty of this paper is the analysis of the porosity with respect to the underlying additive process zone and the sample geometry.

Sewing is the most widely used and preferred method for manufacturing clothing products for extreme weather conditions and other industrial insulation systems. Multiple layers of functional fabrics in combination with insulation materials are used to thermally insulate precious body heat from its surrounding cold environment. The sewing process fixes the insulation material between the fabric layers. During conventional sewing, the insulation material is compressed along the stitch line. With the compression of the insulation material, entrapped air is forced to leave the insulation material internal structure, and heat loss occurs along the entire length of the stitch line. It results in the deterioration of thermal properties of the end product along the stitch line.

The amount of air, which is a decisive factor for thermal properties of any insulation system, was investigated at the level of a unit stitch length of a lockstitch. Conventional microscopy methods are not suitable to study the compression along the stitch line. With the help of X-ray tomography, the three-dimensional data of a stitch was taken and studied to measure the volume of air. The samples were prepared with conventional lockstitch sewing and a newly developed innovative sewing method “Spacer Stitching.” The results are compared with each other in terms of the amount of air present in a unit stitch length.

Calculations based on X-ray tomography images of lockstitch and spacer stitch revealed that, in the case of lockstitch, a unit stitch has a 15% of its volume made up of material and 85% of its volume by air. In comparison, the spacer stitch with the same sewing and fabric parameters has a material volume of 4.6 % and an air volume of 95.4% in a single stitch.

The research can positively improve the thermal properties of sewn material made for insulating purposes of conventional clothing as well as of industrial insulations.

There is no literature available which investigates and calculates the amount of air and material present along with a stitch line.

Cornell University and Xerox Corporation, with the support of the Commission on Preservation and Access, have been collaborating in a project to test a prototype system for recording brittle books as digital images and producing, on demand, high quality and archivally sound paper replacements. The project goes beyond that, however, to investigate some of the issues surrounding scanning, storing, retrieving and providing access to digital images in a network environment.

University of Cincinnati Inaugurates OhioLINK. The University of Cincinnati (UC), first to implement a state‐of‐the‐art computerized Ohio library research system, celebrated the arrival of the technology with inauguration ceremonies.