An Analysis of the Displacements in 3D-Printed PLA Acoustic Guitars.

This study focuses on the analysis of the displacements generated in 3D-printed acoustic guitar tops. Specifically, the influence of 3D printing direction parameters on the vibrational behavior of a guitar top designed for polylactic acid (PLA) by analyzing five points of the top surface at a reduced scale. For this purpose, finite element tests and laboratory experiments have been carried out to support the study. After analyzing the results, it can be affirmed that the vibrational response in reduced-scale top plates can be modified and controlled by varying the printing direction angle in additive manufacturing, providing relevant information about the displacement in the vibrational response of PLA acoustic guitars. Furthermore, this work shows that the behavior of a specific acoustic guitar design can be characterized according to a specific need.

Influence of 3D Printing Direction in PLA Acoustic Guitars on Vibration Response.

The design of musical instruments is a discipline that is still carried out in an artisanal way, with limitations and high costs. With the additive manufacturing technique, it is possible to obtain results for the generation of not only electrical but also acoustic instruments. However, it is necessary to generate a procedure to evaluate the influence of the process on the final result of the acoustics obtained. This study focuses on investigating the relationship between the construction of acoustic guitars and their final sound. The reinforcement structures at the top of the instrument are analysed, as well as how this design affects the vibratory behaviour of the top in the first five vibratory modes. Specifically, this article presents a procedure for the design of customised acoustic guitars using additive manufacturing through parametrisation and a vibrational analysis of the designed tops using finite element (FEA) and experimental physical tests, in order to develop a methodology for the study of stringed instruments. As a result, an 11% increase in the high-frequency response was achieved with a printing direction of +45°, and a reduction in the high-frequency response with ±45°. In addition, at high frequencies, a relative error of 5% was achieved with respect to the simulation. This work fulfils an identified need to study the manufacture of acoustic guitars using polylactic acid (PLA), and to be able to offer the musician a customised instrument. This represents a breakthrough in the use of this manufacturing technology, extending its relationship with product design.

Design of Customized TPU Lattice Structures for Additive Manufacturing: Influence on the Functional Properties in Elastic Products.

This work focuses on evaluating and establishing the relationship of the influence of geometrical and manufacturing parameters in stiffness of additively manufactured TPU lattice structures. The contribution of this work resides in the creation of a methodology that focuses on characterizing the behavior of elastic lattice structures. Likewise, resides in the possibility of using the statistical treatment of results as a guide to find favorable possibilities within the range of parameters studied and to predict the behavior of the structures. In order to characterize their behavior, different types of specimens were designed and tested by finite element simulation of a compression process using Computer Aided Engineering (CAE) tools. The tests showed that the stiffness depends on the topology of the cells of the lattice structure. For structures with different cell topologies, it has been possible to obtain an increase in the reaction force against compression from 24.7 N to 397 N for the same manufacturing conditions. It was shown that other parameters with a defined influence on the stiffness of the structure were the temperature and the unit size of the cells, all due to the development of fusion mechanisms and the variation in the volume of material used, respectively.

Influence of 3D-Printed TPU Properties for the Design of Elastic Products.

The design of products with elastic properties is a paradigm for design engineers because the properties of the material define the correct functionality of the product. Fused filament fabrication (FFF) allows for the printing of products in thermoplastic polyurethanes (TPU). Therefore, it offers the ability to design elastic products with the freedom of forms that this technology allows and also with greater variation of elastic properties than with a conventional process. The internal structures and the variation in thickness that can be used facilitate the design of products with different elastic realities, producing variations in the elasticity of the product with the same material. This work studies the influence of the variation of internal density as a function of basic geometries in order to quantify the difference in elasticity produced on a product when it is designed. Likewise, a case study was carried out with the creation of a fully elastic computer keyboard printed in 3D. The specimens were subjected to compression to characterize the behavior of the structures. The tests showed that the elasticity varies depending on the orientation and geometry, with the highest compressive strength observed in the vertical orientation with 80% lightening. In addition, the internal lightening increases the elasticity progressively but not uniformly with respect to the solid geometry, and also the flat faces favour the reduction in elasticity. This study classifies the behavior of TPU with the aim of being applied to the design and manufacture of products with specific properties. In this work, a totally flexible and functional keyboard was designed, obtaining elasticity values that validate the study carried out.

Product Design by Additive Manufacturing for Water Environments: Study of Degradation and Absorption Behavior of PLA and PETG.

Additive manufacturing technologies are shifting from rapid prototyping technologies to end use or final parts production. Polymeric material extrusion processes have been broadly addressed with a specific definition of all parameters and variables for all different of technologies approaches and materials. Recycled polymeric materials have been studied due to the growing importance of the environmental awareness of the contemporary society. Beside this, little specific research has been found in product development applications for AM where the printed parts are in highly moisture environments or surrounded by water, but polymers have been for long used in such industries with conventional manufacturing approaches. This work focuses on the analysis and comparison of two different additively manufactured polymers printed by fused filament fabrication (FFF) processes using desktop-size printers to be applied for product design. The polymers used have been a recycled material: polyethylene terephthalate glycol (PETG) and polylactic acid (PLA). Degradation and water absorption behaviors of both materials are presented, analyzed and discussed in this paper, where different samples have been immersed in saturated solutions of water with maritime salt and sugar together with a control sample immersed in distilled water. The samples have been dimensionally and weight-controlled weekly as well as microscopically analyzed to understand degradation and absorption processes that appear in the fully saturated solutions. The results revealed how the absorption process is stabilized after a reduced number of weeks for both materials and how the degradation process is more remarked in the PLA material due to its organic nature.

Evaluation of Reliefs' Properties on Design of Thermoformed Packaging Using Fused Deposition Modelling Moulds.

The increased consumption of food requiring thermoformed packaging implies that the packaging industry demands customized solutions in terms of shapes and sizes to make each packaging unique. In particular, food industry increasingly requires more transparent packaging, with greater clarity and a better presentation of the product they contain. However, in turn, the differentiation of packaging is sought through its geometry and quality, as well as the arrangement of food inside the packaging. In addition, these types of packaging usually include ribs in the walls to improve their physical properties. However, these ribs also affect the final aesthetics of the product. In accordance with this, this research study analyses the mechanical properties of different relief geometries that can affect not only their aesthetics but also their strength. For this purpose, tensile and compression tests were carried out using thermoformed PET sheets. The results provide comparative data on the reliefs studied and show that there are differences in the mechanical properties according to shape, size and disposition in the package.

Custom Design of Packaging through Advanced Technologies: A Case Study Applied to Apples.

In the context of food packaging design, customization enhances the value of a product by meeting consumer needs. Personalization is also linked to adaptation, so the properties of the packaging can be improved from several points of view: functional, aesthetic, economic and ecological. Currently, functional and formal properties of packaging are not investigated in depth. However, the study of both properties is the basis for creating a new concept of personalized and sustainable product. In accordance with this approach, a conceptual design procedure of packaging with personalized and adapted geometries based on the digitization of fresh food is proposed in this work. This study is based on the application of advanced technologies for the design and development of food packaging, apples in this work, in order to improve the quality of the packaging. The results obtained show that it is possible to use advanced technologies in the early stages of product design in order to obtain competitive products adapted to new emerging needs.