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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.

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.

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.

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.

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.

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.

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.

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.

The additive manufacturing technologies have been facing an extraordinary growth along the past years. This phenomenon might be correlated with rise of low-cost FDM technologies into the non-professional market segment. In contrast with that, among the main disadvantages found in this sort of equipment are the final object finishing and low mechanical strength. For that reason, the purpose of this paper is to present and characterise a surface treatment which is based on solvent vapour attack and that is also known as smoothing process. In addition, a concise overview about the theory beneath this process is presented besides an experimental study that evaluates the main effects on the mechanical properties of object.

To analyse the benefits of this process, the authors preliminarily investigated the working mechanism that supports such surface treatment. It allowed them to identify and select a proper solvent for each material. The authors have also established that the exposure time repetition numbers (passes) were the main variables, whereas temperature, solvent type, drying time, object direction and object shape were constants. The main object dimensions, surface roughness, absorbed solvent mass and mechanical strength were the main study responses.

As a result of this work, the peak-peak roughness was reduced in 71 per cent, indicating the potential benefit of this process. On the other hand, excessive solvent exposure implied on relevant dimensional distortions and internal disruptures. It was also possible to see that the vapourised solvent penetrate into the object surface and fused layers and filaments. As consequence, the mechanical strength was also improved.

Despite the growth that additive manufacturing market segment has seen along the past years, the finishing and mechanical strength of low-cost equipment still lack for improvements. For that reason, applications like solvent vapour attack or smoothing process new perspectives for this non-professional segment, whereas roughness and mechanical strength are improved after its treatment. As a consequence, it is possible to consider a final object to be obtained directly from low-cost FDM in combination with smoothing process.

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.

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 functional feasibility of technology.

In the material development, the tensile strength of dry composite was identified between 20 and 30 MPa, while the tensile strength of wet composite was between 5 and 12 MPa. It is important to note that the dry and wet cellulose presented tensile strength, respectively, equal to 15 and 1 MPa, indicating the possibility of residual material removal only with the use of water or other soft solvent. The values of adherence between layers (peeling test) were found to be between 0.12 and 0.15 kgf, and the photopolymer formulation which resulted in the maximum adherence has monomer/oligomer ratio equal to 1.5 and 2 per cent wt of photoinitiator percentual. As result of the optimisation study, the material formulation was compounded by monomer – 10 ml, oligomer – 4.5 ml and photoinitiator – 2 per cent, being found suitable to characterise and evaluate the proposed process. The study of composite formation along a straight line showed values of line width between 1,400 and 3,500 μm in accordance with light power, laser velocity and laser beam diameter. On the other hand, the number of previous layers affected by the composite formation varied from 0 to 4, indicating a potential process limit. In the functional feasibility study, a feasible process window which resulted in the maximum dimensional deviation equal to 0.5 mm was identified. In addition, the mean mechanical tensile strength was found to be around 30 MPa for longitudinal laser trajectory (90°) and 15 MPa for transversal laser trajectory (0°), highlighting the anisotropic behaviour of final parts according to the manufacturing strategy.

This paper proposed a novel AM technology and also described studies related to the characterisation of this concept. This work might also be useful to the development of other AM processes and applications.

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.

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 budget of model. Also indicated are the two factors that promote more errors, undergoing a proposal of conception which consists in replacing one component of machine.

With reference to the evaluation of the numerical model, equivalency was found between the resultant error of model and the current FDM accuracy. The result of multivariable study identified the main causes of errors in machine, implying on an optimized solution which decreases the initial error in 69 μm. Similarly, the evaluation of the proposed conception resulted in the reduction of general error in almost 20 μm, even though the worst case was studied for this comparison.

Although the number of applications for additive manufacturing has been growing in recent years, implying an increase of demand for high precision parts, there are still several challenges to be overcome, such as the improvement of equipment. For that reason, the motivation of this work concerns the contribution for development of new equipment, as well the improvement of current technologies. Furthermore, the authors' focus was the reduction of mechanical errors through an analytical approach.

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.

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 deposition modelling (FDM) machines, an optimisation study was performed that focused on the minimisation of both the total cost and final equipment error. The optimisation problem was defined in accordance with the goal attainment method, which allowed identification of the Pareto optimum of the study. The optimisation results were then compared with current equipment concepts, and possible improvements and restrictions of the optimised concept were described.

With regard to the evaluation of the numerical model of final error, the general error in the x‐ and y‐direction was observed to have a deviation of 2 μm, while the numerical error in the z‐direction was found to be inferior to that of currently used equipment. The optimisation study also allowed the identification of the machine elements that provide the minimal error and cost for the equipment, identifying an optimal Pareto of the system. In such an optimal case, the average of the final errors for the balanced solution (in which the objective functions have equal importance) was found to be 141 μm. In addition, the cost of this solution was 1.57 times higher than the cheapest solution found. Finally, a comparison between the configuration of commercial FDM machines and the optimum values was found, highlighting the main points that would possibly provide an improvement to the current concepts and an increase in equipment profitability.

Despite the growth of additive manufacturing development, there are still several challenges to overcome to increase the accuracy of the final parts, such as the reduction of mechanical errors. However, in addition to the complexity of this subject, the cost of equipment restricts the development of new solutions. As a result, a systematic approach to identify a suitable configuration of each machine in accordance with the optimal accuracy and cost of equipment is needed.

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.

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, with the adjustable variables being initiator concentration; power of light source; light wave length; and thickness of layer. The range of values chosen for initiator concentration was between 1 and 10 per cent, while for light power, the range was 5‐9 W. For light wave length, the authors selected 325 and 400 nm as limits for their study and 0.12 and 4 mm as the range for thickness of layers. For the analytical approach of their study, it was possible to identify optimum conditions for curing thick layers, besides looking at optimum condition at each step along the varying thickness. On the other hand, in the experimental approach, the authors just considered the initiator concentration and thickness as variables, applying gravimetric and photometric analysis to determine the conversion curve of material.

In conclusion based on these studies, it was possible to identify the influence of thickness and initiator concentration as function of penetration depth, polymerization rate and homogeneity of material, in addition to determining the effect of light power and light wave length over the process. As a result of these studies, it was possible to identify situations wherein the material will possibly undergo a high degree shrinkage in addition to showing consequences of high quantity of initiator. On the other hand, low concentration of initiator is shown to provide more homogeneous solution besides being more suitable for deep layers. It was also possible to compare analytical and experimental results, making it possible to predict the behaviour of material for other conditions.

The main value of this work is to show the possibility of optimizing photopolymerizable systems through an analytical approach. In addition, it emphasized the viability of the application of UV curable material for producing moulded parts.

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.

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 oligomer. The authors analysed the photopolymerisation rate, viscosity, mechanical tensile strength, flexural stiffness and softening. These results comprise a multiobjective optimisation study to identify the ideal material formulation for additive manufacturing applications. The values chosen for the materials were the following: the initiator concentration was 2 and 5% wt., the monomer volume was 5 and 10 ml and the oligomer volume was 3 and 5 ml. To analyse the system kinetics and the photopolymerisation rate, the authors identified the polymer conversion rate through a photometric-cum-gravimetric method with a wavelength of 390 nm at the peak intensity. For the softening test, the authors identified the stiffness of the material as a function of temperature, characterising the thermal-mechanical behaviour of the material and determining its degree of crystallinity (cross-linking). Additionally, the authors performed an optimisation to maximise the mechanical tensile strength, flexural stiffness, softening temperature and photopolymerisation rate while minimising the viscosity.

Based on these studies, it was possible to identify the influence of the monomer/oligomer ratio and the initiator concentration as function of polymerisation rate, viscosity, mechanical tensile strength, stiffness and softening of the material. It was also possible to determine the photopolymerisation rate in addition to the constants of propagation and termination. As a result of these studies, the authors identified a material formulation that resulted in a softening temperature greater than 70°C, while the viscosity of material remained lower than 3 cP. The mechanical ultimate tensile strength was between 10 and 50 MPa, and the stiffness was between 1.6 and 5.8 GPa. The effect of cross-linking on the process highlighted the interaction between the monomer/oligomer ratio and the initiator. The contribution of the initiator and the inhibitor to the polymerisation rate was identified via a numerical model, which allows the prediction of the material's behaviour in different process conditions, as such curing time and penetration depth.

The main value of this work is to show the possibility of optimized photopolymerizable systems through an experimental approach as a function of the mechanical properties of material. In addition, it emphasised the possibility of predicting the material behaviour in front of different situations.

This study aims to explore the firm’s and country-level institutional forces that determine banks’ CSR reporting diversity, during the recent global financial crisis.

Specifically, this study assesses whether economic and institutional conditions explain CSR disclosure strategies used by 30 listed and unlisted banks from six countries in the context of the recent 2007/2008 global financial crisis. The annual reports and social responsibility reports of the largest banks in Canada, the UK, France, Italy, Spain and Portugal were content analyzed.

The findings suggest that economic factors do not influence CSR disclosure. Institutional factors associated with the legal environment, industry self-regulation and the organization’s commitments in maintaining a dialogue with relevant stakeholders are crucial elements in explaining CSR reporting. Consistent with the Dillard et al.’s (2004) model, CSR disclosure by banks not only stems from institutional legitimacy processes, but also from strategic ones.

The findings highlight the importance of CSR regulation to properly monitor manager’s’ opportunistic use of CSR information and regulate the assurance activities (regarding standards, their profession or even the scope of assurance) to guarantee the proper credibility reliability of CSR information.

The study makes two major contributions. First, it extends and modifies the model used by Chih et al. (2010). Second, drawn on the new institutional sociology, this study develops a theoretical framework that combines the multilevel model of the dynamic process of institutionalization, transposition and deinstitutionalization of organizational practices developed by Dillard et al. (2004) with Campbell’s (2007) theoretical framework of socially responsible behavior. This theoretical framework incorporates a more inclusive social context, aligned with a more comprehensive sociology-based institutional theory (Dillard et al., 2004; Campbell, 2007), which has never been used in the CSR reporting literature hitherto.

We present a critical literature review debating Brazilian research on social and environmental accounting (SEA). The aim of this study is to understand the role of politics in the construction of hegemonies in SEA research in Brazil. In particular, we examine the role of hegemony in relation to the co-option of SEA literature and sustainability in the Brazilian context by the logic of development for economic growth in emerging economies. The methodological approach adopts a post-structural perspective that reflects Laclau and Mouffe’s discourse theory. The study employs a hermeneutical, rhetorical approach to understand and classify 352 Brazilian research articles on SEA. We employ Brown and Fraser’s (2006) categorizations of SEA literature to help in our analysis: the business case, the stakeholder–accountability approach, and the critical case. We argue that the business case is prominent in Brazilian studies. Second-stage analysis suggests that the major themes under discussion include measurement, consulting, and descriptive approach. We argue that these themes illustrate the degree of influence of the hegemonic politics relevant to emerging economics, as these themes predominantly concern economic growth and a capitalist context. This paper discusses trends and practices in the Brazilian literature on SEA and argues that the focus means that SEA avoids critical debates of the role of capitalist logics in an emerging economy concerning sustainability. We urge the Brazilian academy to understand the implications of its reifying agenda and engage, counter-hegemonically, in a social and political agenda beyond the hegemonic support of a particular set of capitalist interests.