SLS Process Parameter Optimization to Improve Surface Quality and Accuracy of Polyamide Parts

The contribution of selective laser sintering (SLS) technique in the 4.0 manufacturing industry is undisputedly significant. SLS part quality exhibits high dependence on SLS process parameters and is a major challenge. Therefore, this research aims to investigate the effect of input parameters (i.e., part orientation, bed temperature, and layer thickness) on the surface roughness and accuracy of laser-sintered polyamide specimens. Response surface methodology (RSM) and ANOVA analysis aided the testing and evaluation. Optimal working conditions for minimum shrinkage were 0.17 mm layer thickness, 177.89°C part bed temperature, and part orientation at 88.91 degrees. The surface quality deteriorated with the increment in part bed temperature and layer thickness, and it shows an inverse trend (or improves) with the part orientation in the prescribed range. The optimal surface roughness was at a layer thickness of 0.11 mm, bed temperature at 174.55°C, and part orientation at 86.5 degrees.

Influence of Part Orientation on the Surface Roughness in the Process of Fused Deposition Modeling

The article focused on the influence of part orientation on the surface roughness of cuboid parts during the process of fabricating by FDM technology. The components, in this case, is simple cuboid part with the dimensions 15 mm x 15mm x 30 mm. A geometrical model is defined that considers the shape of the material filaments after deposition, to define a theoretical roughness profile, for a certain print orientation angle. Five different print orientations in the X-axis of the cuboid part were set: 0°, 30°, 45°, 60°, and 90°. According to previous research in the field of FDM technology by the author, the internal structure (infill) was set at the value of 70%. The method of 3D printing was the Fused Deposition Modeling (FDM) and the material used in this research was thermoplastic ABS (Acrylonitrile butadiene styrene). For each setting, there were five specimens (twenty five prints in total). Prints were fabricated on a Zortrax M200 3D printer. After the 3D printing, the surface “A” was investigated by portable surface roughness tester Mitutoyo SJ-210. Surface roughness in the article is shown in the form of graphs (Fig.7). Results show increase in part roughness with increasing degree of part orientation. When the direction of applied layers on the measured surface was horizontal, significant improvement in surface roughness was observed. Findings in this paper can be taken into consideration when designing parts, as they can contribute in achieving lower surface roughness values.

Factors Affecting Ultimate Tensile Strength and Impact Toughness of 3D Printed Parts Using Fractional Factorial Design

This paper aims to investigate the mechanical properties of spec- imens printed by 3D open-source printers. It discusses the effect of five fac- tors (part/print orientation, layer height, extrusion width, nozzle diameter, and filament temperature) on the ultimate tensile strength and the impact toughness of the 3D-printed samples. A 2 6-1 resolution V fractional factorial experiment was run with the 16 samples printed on a Prusa I3 MK3S in PLA. Tensile strength and impact toughness were tested using Instron 3367 and Tinius Olsen 66 testers, respectively. In analyzing the data, a normal proba- bility plot complimented with ANOVA (Analysis Of Variance) revealed that only part/print orientation was statistically significant at p = 0.05. Regression equations were used to predict the ultimate tensile strength and the impact toughness as a function of the part/print orientation. Both the toughness re- sponse and the tensile strength response are maximized with horizontal part orientation. Verification experiments have been implemented to validate the adopted regression equations’ predictions under different circumstances and the results of those experiments appear to confirm the model.

PART ORIENTATION AND SEPARATION TO REDUCE PROCESS COSTS IN ADDITIVE MANUFACTURING

Additive manufacturing offers great potential in geometric design through the layer-by-layer production of components. This is often used in the development of additively manufactured components to make components lighter. An even greater reduction in mass is possible if several components are combined into a more complex component. However, as complexity increases, so do the manufacturing costs, due to a higher demand for supporting structure, reworking and longer production time. Especially for complex components, which make poor use of the space available in the additive manufacturing system, component separation can be a useful way of reducing manufacturing costs. Therefore, a procedure for automated component separation is presented, which determines an optimal cutting plane with respect to the manufacturing costs. The presented procedure is evaluated using two exemplary components where a reduction of manufacturing costs up to 54 % could be achieved.

KNOWLEDGE-BASED EVALUATION OF PART ORIENTATION DESIRABILITY IN POWDER BED FUSION ADDITIVE MANUFACTURING

In powder bed fusion (PBF) additive manufacturing, the definition of part orientation is one of the most important steps as it affects the quality, the cost and the build time of products. Different works already attempted to propose methodologies for the assessment of optimal build orientation based on criteria such as the minimization of support volume. Elicitation works with industry experts have shown that they use much more varied rules to determine the orientation of parts. For instance, they do not treat the different surfaces of the part the same way (e.g., experts state that “priority surfaces of the part must be oriented close to vertical”). Today, the available tools do not allow integrating these kind of specifications. This paper discusses a knowledge-based methodology for the evaluation of part candidate orientations in PBF. Desirability function approach is used to translate companies’ expertise in the form action rules into mathematical functions that are tested on geometries to provide metrics for assisting the decision-making. A case study is presented to illustrate the use of this desirability function approach on complex part orientation problem.

Additive manufacturing casestudy and implementation strategy

The following report has been created to provide a broad range of information on current additive manufacturing technologies, their present applications in commercial and industrial sectors and predictions for their future deployment in those sectors. The report also examines the ongoing research and development of a variety of 3D printing techniques. The review is divided into three sections. The first section is composed of one to two page summaries of academic journals, thesis papers, consultant perspective articles and company releases. Each individual summary provides a synopsis of the article, as well as what the authors foresee as the future implications of the topic they explored. The second section contains summaries and reviews of technical studies on various aspects of several different 3D printing technologies. Lastly the third section introduces implementation strategy for 3D printed components and presents a study that highlights the effect of part orientation on the structural integrity of the printed components.

Additive manufacturing casestudy and implementation strategy

The following report has been created to provide a broad range of information on current additive manufacturing technologies, their present applications in commercial and industrial sectors and predictions for their future deployment in those sectors. The report also examines the ongoing research and development of a variety of 3D printing techniques. The review is divided into three sections. The first section is composed of one to two page summaries of academic journals, thesis papers, consultant perspective articles and company releases. Each individual summary provides a synopsis of the article, as well as what the authors foresee as the future implications of the topic they explored. The second section contains summaries and reviews of technical studies on various aspects of several different 3D printing technologies. Lastly the third section introduces implementation strategy for 3D printed components and presents a study that highlights the effect of part orientation on the structural integrity of the printed components.

Status, issues, and future of computer-aided part orientation for additive manufacturing

Part orientation is a critical task in the process of additive manufacturing product realisation. Recently, various computer-aided methods for this task have been presented in the literature. The coexistence of different methods generates a series of questions: What are the common characteristics of these methods? What are the specific characteristics of each method? What are the main issues in computer-aided part orientation for additive manufacturing currently? What are the potential research directions in this field in the future? To approach these questions, a review of the existing computer-aided part orientation methods for additive manufacturing is presented in this paper. This review starts with a clarification of a part orientation problem and a classification of the existing methods into two categories according to their process of solving the problem. An overview of the representative methods in each category is then carried out from the aspects of approaches for orientation search, generation, or selection, estimation of build orientation factors, determination of weights of factors, establishment of overall objective function, and demonstration of effectiveness. After that, a discussion about the main issues in computer-aided part orientation for additive manufacturing is documented based on the overview. Finally, a suggestion of some future research directions in this field is reported.