Marlon Wesley Machado Cunico

Development of new rapid prototyping process

Purpose – The purpose of this paper is to identify the key elements of a new rapid prototyping process, which involves layer‐by‐layer deposition of liquid‐state material and at the same time using an ultraviolet line source to cure the deposited material. This paper reports studies about the behaviour of filaments, deposition accuracy, filaments interaction and functional feasibility of system. Additionally, the author describes the process which has been proposed, the equipment that has been used for these studies and the material which was developed in this application.Design/methodology/approach – The research has been separated into three study areas in accordance with their goals. In the first, both the behaviour of filament and deposition accuracy was studied. The design of the experiment is described with focus on four response factors (bead width, filament quality, deposition accuracy and deposition continuity) along with function of three control factors (deposition height, deposition velocity an...

Optimization of positioning system of FDM machine design using analytical approach

Purpose – The purpose of this paper is to analyse the conception of the positioning system of fused deposition modeling (FDM) machines, optimising design parameter and components accuracy to decrease mechanical errors of equipment, which, consequently, results in the increase of parts accuracy. This paper also reports studies related to analytical estimation of machine errors, describing a theoretical model which was used for the multivariable study. Additionally, an alternative conception is proposed, according with the result of this study.Design/methodology/approach – For elaboration of the numerical model of equipment, the authors have focused on conception of first generation of FDM, specifying as design parameters, timing belt stiffness, linear bearing clearance, and accuracy grade of ball screw housing, support and pulley. In order to identify the main effect of each design parameter for the final error of machine, the authors have applied a multivariable method in addition to identifying the error...

Development of acrylate-based material using a multivariable approach: additive manufacturing applications

Purpose – Over the last several years, the range of applications for the photopolymerisation process has been steadily increasing, especially in such areas as rapid prototyping, UV inks, UV coats and orthodontic applications. In spite of this increase, there are still several challenges to be overcome when the application concerns materials formulation and their mechanical properties. In this context, the main aim of this work is to outline the contribution of the formulation components for the parameters of the photopolymerisation process and the resultant mechanical properties of the material. Design/methodology/approach – For this research, the authors have applied multivariable analysis methods, which allow the identification of principal conclusions based on experimental results. For the experimental analysis, the authors applied design of experiment, while the material formulation was based on methyl methacrylate as a monomer, Omnrad 2500 as a photoinitiator and trimethylolpropane triacrylate as an ...

Study and optimisation of FDM process parameters for support-material-free deposition of filaments and increased layer adherence

As a consequence of the growth in additive manufacturing applications, research on the improvement of these processes has gained relevance. One such process, the Fused Deposition Modelling (FDM)-process, deposits a support material to build negative surface features such as snap-fits. The purpose of this work is to determine the parameters that enable the fabrication of these types of features without a support material. We applied a design-of-experiments method to identify the quality of the non-supported deposition and the adherence between layers. As to control factors, we defined the deposition temperature and the extrusion and deposition velocities, while the nozzle diameter and the deposition height were held constant. For response factors, we defined the distance, the non-supported deposition quality, and the ultimate tensile stress. Additionally, an optimisation study was performed to maximise the mechanical strength and the non-supported distance, thereby making it possible to determine the suitable range of parameters for implementation of the process.

Design of an FDM positioning system and application of an error‐cost multiobjective optimization approach

Purpose – As a result of the increased number of applications for additive manufacturing technologies and in addition to the demand for parts produced with high accuracy and better quality, the need for the improvement of positioning and precision equipment in manufacturing has become evident. To address this needed improvement, the main goal of this work is to provide a systematic approach for designing additive manufacturing machines, allowing the identification of the relationship between estimated errors and the cost of equipment. In the same way, this study also intends to indicate a suitable configuration of a machine as a function of final accuracy and total equipment cost.Design/methodology/approach – To identify the suitable elements of the machine, a numerical model that estimates the final error and relative cost of equipment as a function of cost and tolerance of the machine elements was constructed and evaluated. After evaluating this model by comparing it with first‐generation fused depositi...

Development of novel additive manufacturing technology: an investigation of a selective composite formation process

Purpose – The purpose of this study is to present a novel additive manufacturing (AM) technology which is based on selective formation of cellulose-acrylate composite. Besides proposing a process that combines the benefits of fibres and photopolymers, this paper reports the development of material, characterisation of a straight line composite formation, adherence between layers and functional feasibility of the proposed concept. Design/methodology/approach – For the preliminary evaluation of the proposed process, a composite material based on cellulose-photopolymer was developed, while a multi-objective optimisation study indicated the formulation which results in the maximum values of layer adherence, tensile strength of composite and the effect of the water on the mechanical strength of material. For the characterisation of the process, three main subjects were analysed: the characterisation of straight line composite formation, the effect of composite formation process on previous layers and the funct...

Optimization of thick layers photopolymerization systems applying experimental and analytical approach

Purpose – Over the last several years, the range of applications of photopolymerization process has been steadily increasing, especially in areas such as rapid prototyping, UV inks, UV coats and orthodontic applications. In spite of this, there are still several challenges to be overcome when the application concerns materials with thick layers. In this context, the main goal of this work is to outline a scheme to optimize the process of photopolymerizarion for thick layers, identifying its differences in relation to those applicable for thin layers.Design/methodology/approach – For this research, the authors have applied multivariable analysis methods which allow the identification of principal conclusions, based on analytical and experimental results. For analytical analysis, the authors applied numerical optimization for multivariables, while experimental analysis was done based on design of experiments. Both the analyses were based on methyl methacrylate as monomer and Omnirad 2500 as photoinitiator, ...

Development and characterisation of 3D printing finishing process applying recycled plastic waste

ABSTRACT In recent years, additive manufacturing technologies have been playing an important role in the global economy. Consequently, low-cost 3D printers rose in the domestic environment, accelerating the development of startup companies and new market segments. Nevertheless, with regard to 3D printing based on fused filament fabrication, several challenges still need to be overcome, such as those related to surface finishing and mechanical strength. Moreover, 3D printing in the domestic environment also generates untreated plastic waste, which can cause environmental problems. For these reasons, the main goal of this work is to introduce and characterise 3D printing surface finishing post-processing using recycled plastic waste. As the main results of this work, the proposed recycling process was confirmed to improve object properties. Whereas surface roughness was reduced from 27 to 3 µm, while mechanical strength was increased in 20 times. The application of recycled material for chemical welding was also seen to be feasible.

Development of additive manufacturing technology based on selective metal-polymer composite formation

Purpose During the past years, numerous market segments have increasingly adopted additive manufacturing technologies for product development and complex parts design. Consequently, recent developments have expanded the technologies, materials and applications in support of emerging needs, in addition to improving current processes. The present work aims to propose and characterise a new technology that is based on selective formation of metal-polymer composites with low power source. Design/methodology/approach To develop this project, the authors have divided this work in three parts: material development, process feasibility and process optimisation. For the polymeric material development, investigation of metallic and composite materials assessed each material’s suitability for selective composite formation besides residual material removal. The primary focus was the evaluation of proposed process feasibility. The authors applied multivariable methods, where the main responses were line width, penetration depth, residual material removal feasibility, layer adherence strength, mechanical strength and dimensional deviation of resultant object. The laser trace speed, distance between formation lines and laser diameter were the main variables. Removal agent and polymeric material formulation were constants. In the last part of this work, the authors applied a multi-objective optimisation. The optimisation objectives minimized processing time and dimensional deviation while maximizing mechanical strength in xy direction and mechanical strength in z direction. Findings With respect to material development, the polymeric material tensile strength was found between 30 and 45 MPa at break. It was also seen that this material has low viscosity before polymerized (between 2 and 20 cP) essential for composite formation and complete material removal. In that way, the authors also identified that the residual material removal process was possible by redox reaction. In contrast with that the final object was marked by the polymer which covers the metallic matrix, protecting the object protects against chemical reactions. For the feasibility study, the authors identified the process windows for adherence between composite layers, demonstrating the process feasibility. The composite mechanical strength was shown to be between 120 and 135 MPa in xy direction and between 35 and 45 MPa in z direction. In addition, the authors have also evidenced that the geometrical dimensional distortion might vary until 5 mm, depending on process configuration. Despite that, the authors identified an optimised configuration that exposes the potential application of this new technology. As this work is still in a preliminary development stage, further studies are needed to be done to better understand the process and market segments wherein it might be applied. Originality/value This paper proposed a new and innovative additive manufacturing technology which is based on metal-polymer composites using low power source. Additionally, this work also described studies related to the investigation of concept feasibility and proposed process characterisation. The authors have focused on material development and studied the functional feasibility, which at the same time might be useful to the development of other additive manufacturing processes.

Analysis of new additive manufacturing technology based on selective composite formation using finite element method approach

Purpose Over the past few years, the number of related research to additive manufacturing (AM) has risen. The selective composite formation (SCF) can also be found among the new technologies that were developed. This technology was first introduced in 2013, and because of its innovative character, there are still many challenges to be overcome. Therefore, the main aim of this study is to present a finite element method which allows to investigate the processing of the material during the selective formation of a composite material based on cellulose and acrylic. Design/methodology/approach In the beginning, we introduced a brand new finite element method approach which is based on light transmittance network and photopolymerisation in transient state. This method is mainly characterised by internal light absorption, transversal reflectance, light transmittance coefficient and photopolymerisation kinetics. The authors defined experimentally the main model coefficients besides investigating the formation of composite material in six case studies. The main variables evaluated in those studies were the number of layers and the number of lines. By the end, the degree of polymer conversion and the preliminary evaluation of adherence between layers were identified in addition to the formation profile of composite material. Findings The presented method evidence that the SCF resulted in a profile of polymerisation which is different from profiles found in vat polymerisation processes. It was shown that the light diffraction increases polymerisation area to outside of laser limits and reduces the penetration depth. It was also exposed that the selective formation of composite material on the top layer interferes with the polymerisation of previous layers and might increase the polymerised area in about 25 per cent per layer. By the end, adherence between layers was evidenced because of a high-pass filter that limited polymer conversion to over 60 per cent. In this case, the adherence between the top layers was provided by the interface between layers, while the deeper layers resulted in a solid formed by composite. Originality/value This paper presents research results related to a very new AM technology and also proposes a new method to characterise this concept. Because of this new analytic approach, the process planning can be simulated and optimised, in addition to being a useful tool for other researches related to photocurable polymers and AM technologies.