1. Introduction
The process of synthesizing layers of materials to produce precise parts or finished goods is known as additive manufacturing (AM) [
1]. A computer-aided design (CAD) model serves as the blueprint for the additive manufacturing process, which entails building three-dimensional parts by gradually integrating material in the form of layers [
2]. The process of additive manufacturing may create parts with decent precision and a small amount of waste [
3]. The ability of AM technology to get a product to market more quickly than traditional techniques has caused its use to explode over the past few decades [
4]. According to Forbes, 95% of manufacturing firms believe that 3D printing technology offers a sizable competitive edge. 57% of worldwide companies made investments in 3D printing research and development. Additionally, research demonstrates that 47% of 3D printing companies have had greater success than in past years [
5]. According to estimates, the AM industry will increase by an average of 24%, or 35 billion US dollars, during the next five years [
6]. The AM sector expanded by 7.5%, or roughly
$12.8 billion US dollars, in 2020. AM is currently an area of interest for bio-printing and is employed in a wide range of industries, comprising the ceramic, polymer, biomedical, and industrial of composite materials [
7,
8,
9]. Powder bed fusion, direct energy deposition, material extrusion, binder jetting, material jetting, sheet lamination, and VAT photopolymerization are some of the various types of AM technology [
10].
Polymers are used as a filament in fused deposition modeling (FDM), sometimes referred to as the material extrusion AM technology. Typically, the filament is heated until it becomes molten, at which point it is extruded through the machine's nozzle. A significant reduction in processing time can be achieved by using lightweight materials to create complex shapes with the FDM technique [
11,
12]. In contrast to other AM methods that make use of various laser systems, powders, and resins. It stands out as a widely used technology that extrudes semi-solid thermoplastic material via a nozzle [
13]. FDM, also referred to as fused filament fabrication (FFF), was a popular technique for extruding materials. After being drawn through a nozzle and heated there, hot layers of material are then deposited. Due to its simplicity, adaptability, speed of processing, cheap cost, dependability, low waste, range of materials, and ability to deal with new materials, FDM is also among the most extensively used methods. The FDM technology was created in 1989 by Stratasys, Ltd., one of the leading participants in the global marketplace for 3D printing. FDM technology makes up over 40% of the global market. The most widely used AM technology is FDM because of its speed production, accessibility, cost-effectiveness, wide range of material versatility, and capacity to create complicated parts. [
14]. The most comprehensively researched thermoplastic polymer materials used in the FDM method consist of acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), polypropylene (PP), polyethylene terephthalate (PET), and high-density polyethylene (HDPE) [
15,
16].
Numerous earlier scholars investigated the effect of the FDM 3D printer's printing parameters. They researched variables such as printing speed, layer thickness, orientation, raster angle, and pattern infill [
17,
18,
19,
20]. ABS material was utilized by Sharma et al. [
21] and Vicente et al. [
22] to examine the influence of layer thickness on mechanical behavior. The FDM factors that received the greatest attention throughout the research were build orientation, layer thickness, raster orientation, air gap, infill density, and raster width. The most significant variables affecting the product's mechanical properties, dimensional accuracy, and surface roughness, according to previous studies, are thickness and orientation. The support material and fabrication time optimization on FDM were examined by Pavan Kumar and Regalla et al. [
23] using the DOE approach. According to the analysis of variance (ANOVA) results, the sample's orientation was determined to be essential for minimizing build time, and build time is reduced when the raster angle, raster width, layer thickness, and contour width rise. According to Nancharaiah et al.'s ANOVA analysis [
24], the raster width and layer thickness had a substantial impact on the product's part accuracy and surface finish. In order to prepare the sample and conduct mechanical experiments, research organizations used ASTM-established standards. For instance, practically all research organizations that tested for tensile testing employed ASTM D638 [
25].
A high percentage of studies indicated that the process variables primarily influence the part's tensile strength, elongation, and elastic modulus. Furthermore, mechanical performance was shown to depend on printing conditions in almost all of the research published [
26]. The part orientation and the inadequate interlayer bonding have the biggest impacts on the sample's tensile strength. Additionally, both parallel and longitudinal materials can produce materials that have elevated tensile in the printing direction [
27]. Hossain et al. [
28] investigated methods to manipulate the contour width, air gap, build orientation, and raster angle in order to increase Young's modulus, ultimate tensile strength, and tensile strain. The evaluation has been conducted using the default, visual response, and insight methods. The results showed that by employing the insight approach to optimize process parameters, a greater UTS could be achieved. The mechanical characteristics and microstructure of the FDM-printed ABS parts at various raster angle orientations were investigated by Fatimatuzahraa et al. [
29]. The results demonstrated that constructions with a cross-sectional angle of 45° have greater performance for impact, flexural, and deflection tests.
Researchers frequently used the scanning electron microscope (SEM) technology in their research. It is an accurate and efficient approach to evaluate a material's surface morphology. The samples' fractured surfaces underwent morphological examination by Atakok et al. [
30]. The test parts' resistance to deformation was decreased by their porous structure and the significant surface voids that they had created. The parallel layers created by the FDM process are clearly visible in the cross-section of the fracture test parts. According to Lyu et al. [
31], the interlayer bonding of the three samples had similarities as seen in the SEM images. The number of pores and adhesion between the filaments were greatly influenced by the 3D printing parameters, which in turn affected the samples' yield strength. For SEM microscopy investigation, the samples with the finest fracture were chosen [
32]. The outcome demonstrates that when the infill percentage declined, the amount of the infill voids grew larger. Therefore, the characteristics dropped as the size of the voids increased and the interaction between the layers became weaker. Based on the literature, there had been less research conducted regarding the effects of parameters for the FDM 3D printer (model Up Plus 2) using ABS filament. In order to better understand how 3D printing factors, affect important mechanical characteristics including tensile strength and tensile modulus of ABS material produced by an FDM 3D printer, this study will investigate those effects.