Omar Ahmed Mohamed

Experimental Investigations of Process Parameters Influence on Rheological Behavior and Dynamic Mechanical Properties of FDM Manufactured Parts

Fused deposition modeling (FDM) has gained popularity in industry because of its ability to manufacture complex parts. But when it comes to the manufacturing of functional products, the advantages of FDM are not so distinct due to the high number of intervening parameters and complex optimal settings setup. This paper investigates the influence of process parameters on the rheological and dynamic mechanical properties of FDM-manufactured parts. In this study, an attempt has been made to establish an empirical relationship between the FDM input parameters and the properties involved using IV-optimal response surface methodology and statistical analysis. Further, optimized process parameters were established to maximize the rheological and dynamic mechanical properties through the graphical optimization. The optimization results show that the parameters with the most significant effect on the rheological and dynamic mechanical properties are the layer thickness, the air gap, the road width, and the number of contours. The results also show that by taking into consideration the number of contours, the functionality of manufactured part is improved significantly.

Analytical Modelling and Optimization of the Temperature-Dependent Dynamic Mechanical Properties of Fused Deposition Fabricated Parts Made of PC-ABS

Fused deposition modeling (FDM) additive manufacturing has been intensively used for many industrial applications due to its attractive advantages over traditional manufacturing processes. The process parameters used in FDM have significant influence on the part quality and its properties. This process produces the plastic part through complex mechanisms and it involves complex relationships between the manufacturing conditions and the quality of the processed part. In the present study, the influence of multi-level manufacturing parameters on the temperature-dependent dynamic mechanical properties of FDM processed parts was investigated using IV-optimality response surface methodology (RSM) and multilayer feed-forward neural networks (MFNNs). The process parameters considered for optimization and investigation are slice thickness, raster to raster air gap, deposition angle, part print direction, bead width, and number of perimeters. Storage compliance and loss compliance were considered as response variables. The effect of each process parameter was investigated using developed regression models and multiple regression analysis. The surface characteristics are studied using scanning electron microscope (SEM). Furthermore, performance of optimum conditions was determined and validated by conducting confirmation experiment. The comparison between the experimental values and the predicted values by IV-Optimal RSM and MFNN was conducted for each experimental run and results indicate that the MFNN provides better predictions than IV-Optimal RSM.

Experimental investigation for dynamic stiffness and dimensional accuracy of FDM manufactured part using IV-Optimal response surface design

Purpose Fused deposition modeling (FDM) has become an increasingly important process among the available additive manufacturing technologies in various industries. Although there are many advantages of FDM process, a downside of its industrial application is the attainable dimensional accuracy with tight tolerance without compromising the mechanical performance. This paper aims to study the effects of six FDM operating parameters on two conflicting responses, namely, dynamic stiffness and dimensional stability of FDM produced PC-ABS parts. This study also aims to determine the optimal process settings using graphical optimization that satisfy the dynamic mechanical properties without compromising the dimensional accuracy. Design/methodology/approach The regression models based upon IV-optimal response surface methodology are developed to study the variation of dimensional accuracy and dynamic mechanical properties with changes in process parameter settings. Statistical analysis was conducted to establish the relationships between process variables and dimensional accuracy and dynamic stiffness. Analysis of variance is used to define the level of significance of the FDM operating parameters. Scanning electron microscope and Leica MZ6 optical microscope are used to examine and characterize the morphology of the structures for some specimens. Findings Experimental results highlight the individual and interaction effects of processing conditions on the dynamic stiffness and part accuracy. The results showed that layer thickness (slice height), raster-to-raster air gap and number of outlines have the largest effect on the dynamic stiffness and dimensional accuracy. The results also showed an interesting phenomenon of the effect of number of contours and the influence of other process parameters. The optimal process conditions for highest mechanical performance and part accuracy are obtained. Originality/value The effect of FDM processing parameters on the properties under dynamic and cyclic loading conditions has not been studied in the previous published work. Furthermore, simultaneous optimization of dynamic mechanical properties without compromising the dimensional accuracy has also been investigated. On the basis of experimental findings, it is possible to provide practical suggestions to set the optimal FDM process parameters in relation to dynamic mechanical performance, as well as the dimensional accuracy.

Influence of processing parameters on creep and recovery behavior of FDM manufactured part using definitive screening design and ANN

Purpose The purpose of this paper is to investigate the effect of process parameters of fused deposition modelling (FDM) 3D printing process on viscoelastic responses (creep compliance and recoverable compliance) of FDM built parts using a novel experimental design technique. Design/methodology/approach As part of the process characterization, a recently developed class of three-level design methodology – definitive screening design (DSD) – was used in this study to fit a second-order polynomial regression model. Artificial neural network (ANN) was also used to determine the optimal process parameters to improve creep compliance and recoverable compliance. The relationship between layer thickness, air gap, raster angle, build orientation, road width, number of contours and creep performance of FDM fabricated part was thereafter established empirically. Scanning electron microscope (SEM) is used to examine and characterize the morphology of the structures for some samples. Findings This study found that the creep resistance of FDM-manufactured part is significantly influenced by layer thickness, air gap, raster angle and number of contours and it can be improved by optimizing the settings of the selected parameters. The relationship between FDM process parameters and creep properties was determined, with the best creep performance observed by using 0.127 mm of layer thickness, zero air gap, zero raster angle, build orientation of 17.188°, road width of 0.4572 mm and 10 contours. Finally, the result is verified by confirmation experiments. The results prove that a DSD is a very effective design in characterizing the influence of process parameters on creep properties of FDM-built part at the lowest cost. Originality/value The originality of this paper lies in characterizing and optimizing the effect of process parameters on creep performance of FDM manufactured part that has not been studied in all previous studies. The paper highlights, for the first time, how the application of DSD can overcome most of the limitations encountered in the conventional techniques. This study can be used as a guide to the different additive manufacturing users of various industries and the results provide a good technical database on how FDM process parameters influence the creep performance of manufactured parts.

Experimental investigation of the influence of fabrication conditions on dynamic viscoelastic properties of PC-ABS processed parts by FDM process

This paper presents optimization studies on manufacturing parameters for fused deposition modelling (FDM). Layer thickness, air gap, raster angle, build orientation, road width and number of contours are the process variables considered for optimization. Dynamic modulus and glass transition temperature were considered as response parameters. Experiments were designed using fractional factorial design. The effect of each process parameter was investigated using developed regression models and through analysis of variance (ANOVA) technique. The surface characteristics are studied using scanning electron microscope (SEM). Further, performance of optimum conditions was determined and validated by confirmation experiment.

Investigation of the influence of FDM operating parameters on dynamic force response using IV-optimal design and principal component analysis

To improve the functionality in regards to manufacturing products at low cost, several innovative additive manufacturing processes have been developed. Fused deposition modeling (FDM) is one the most prominent additive manufacturing processes for producing plastic products. Referring to the quality and functionality, there are many FDM process conditions contributing to the occurrence of poor quality and functionality of FDM manufactured products. Therefore, the effect of the build parameters on the functionality of FDM produced products need to be examined. In this study, an attempt has also been made to investigate the critical processing parameters affecting dynamic mechanical response of plastic part processed by FDM technology using IV-optimal response surface method coupled with principal component analysis technique. The results obtained from this study can be used in the future as a guide for future in selecting the appropriate process conditions before the manufacturing process of the product tak...

An investigation on impact resistance of FDM processed Nylon-12 parts using response surface methodology

Fused Deposition Modelling (FDM) is one of the leading additive manufacturing processes for plastic part manufacturing. However, engineers often face difficulties to specify the actual levels of process parameters in FDM process to achieve the proper mechanical properties of FDM fabricated parts. The effect of large number of FDM process parameters and the interaction among them need to be understood to achieve desired level of mechanical performance. This paper presents a study on the influence of three FDM process parameters (air gap, raster angle, and build orientation) on the impact strength and mechanical properties of the FDM Nylon 12 fabricated parts by Fortus 450mc FDM machine. The Response Surface Methodology (RSM) based on face centered central composite design was used to analyse, validate, and optimize the results. The significance of parameters was statistically validated with the analysis of variance (ANOVA) technique. The results show that the part build Y-orientations (flat) at 0° and 45° have a significant directly proportional influence on the impact strength, while Z-orientation (upright) at 90° has indirectly proportional effect on the impact strength. Moreover, raster angle has a much significant directly proportional influence on the impact strength at 0° and 60° angles and indirectly proportion influence at 30°.

Effects of build parameters on linear wear loss in plastic part produced by fused deposition modeling

Fused Deposition Modeling (FDM) is one of the prominent additive manufacturing technologies for producing polymer products. FDM is a complex additive manufacturing process that can be influenced by many processثconditions. The industrial demands required from the FDM process are increasing with higher level product functionality and properties. The functionality and performance of FDM manufactured parts are greatly influenced by the combination of many various FDM process parameters. Designers and researchers always pay attention to study the effects of FDM process parameters on different product functionalities and properties such as mechanical strength, surface quality, dimensional accuracy, build time and material consumption. However, very limited studies have been carried out to investigate and optimize the effect of FDM build parameters on wear performance. This study focuses on the effect of different build parameters on micro-structural and wear performance of FDM specimens using definitive screen...