Warping Deformation of Desktop 3D Printed Parts Manufactured by Open Source Fused Deposition Modeling (FDM) System

Transcription

1 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:04 7 Warping Deformation of Desktop 3D Printed Parts Manufactured by Open Source Fused Deposition Modeling (FDM) System Mohammad S. Alsoufi * and Abdulrhman E. Elsayed Department of Mechanical Engineering, College of Engineering and Islamic Architecture, Umm Al-Qura University, Makkah, KSA * Corresponding author: mssoufi@uqu.edu.sa Abstract-- The past few years have observed a fast increase in the popularity of 3D printing technology, e.g., for rapid prototyping. Additive manufacturing (AM) represents a spectrum of technology producing 3D printed parts layer-by-layer or even path-by-path. The aim of this paper is to study and minimize the deformation of open source FDM 3D prints focusing on the different process parameters. More precisely, this paper tackles the influence of the different nozzle temperatures ranging from 180 C to 220 C and printing speeds ranging from 5 mm/s to 20 mm/s on the FDM 3D components during the printing process. The process involved FDM 3D solid modeling as regards design, FDM 3D printing with PLA+ filament material with flat 45 /-45 build orientation, deformation measurement and statistical analysis. The experiment produced the minimum result of deformation value that can be achieved when the nozzle temperature was 220 C by reaching 2.0% at corner 1 (starting point) and 4.55% overall for FDM 3D printed part 1 (15 mm/s printing speed) when using coated thermos adhesive applied to the printing platform. It also shows that less than 1% can be reached when 20 mm/s printing speed and 220 C nozzle temperature is selected. Index Term-- Warping Deformation, 3D Prints, FDM. 1. INTRODUCTION Open source fused deposition modeling (FDM) is the most frequently used 3D printing technology, with excellent mechanical, thermal, and chemical resistance [1, 2]. FDM was developed in late 80 s and commercialized the first 3D product by Stratasys, Ltd., in the USA in the early 90 s [3]. Most of the previous studies on FDM 3D printing describe in detail the process (e.g., [4, 5]). The basic idea varied slightly among types of sources and given below is one of the most commonly used schemes. Concerning this technology, many scientific researchers agree that the FDM 3D printed parts are built up by heating and extruding long-fiber thermoplastic (LFT) polymer filament to a temperature close to the point of fusion through a heated circular nozzle and that this is then deposited in a semimolten state to create the desired shape. When LFT becomes cold, the internal stresses may create deformations around the corners [6]. The production line of any plastic component has been revolutionized for a broad range of industrial applications and it has also been gradually replacing conventional subtractive manufacturing methodologies which often remove up to 95% of the raw material to arrive at a finished component [7-9]. Additive manufacturing (AM) also known as 3D Printing is the process of joining materials to create a three-dimensional model usually layer-by-layer or path-by-path in which layers of material are formed. With the evolution of AM, is has become much easier to manufacture a 3D physical object of any shape directly using a computer aided design (CAD) model from huge numerical data by a fast, flexible process and automated system [10]. This was once thought impossible and it significantly reduces the manufacturing lead-time performance of the product by up to 50%, even if the plastic component complexity is high [11]. Nevertheless, one of the disadvantages of the open source FDM 3D printer is the plastic filament material that comes out from the circular nozzle, which tends to shrink, warp and peel away from the platform. This shrink or warp deformation issues in the FDM 3D printer have been emphasized by many investigators [7, 12, 13]. Additional surface preparation involving applying synthetic thermos adhesive between the first layer and the platform had been performed to overcome this problem [14]. However, due to the different FDM 3D printer process parameter settings, deformation remains a possibility and because of that, the best FDM 3D printer process parameters setting needs to be identified to acquire high quality FDM 3D printing parts. To the best of our knowledge, there is no publication available systematically assessing the deformation of FMD 3D parts using advanced polylactic acid (PLA+) filament at each corner made by AM where the temperatures range from 180 C to 220 C as the independent variable and printing speeds range from 5 mm/s to 20 mm/s as another independent variable for validating the results. Hence, the main purpose of this paper is to investigate how the FDM 3D printer process parameters affected the deformation and to establish the best process parameter values to minimize the deformation. Also, to find out the deformation at each corner of the FDM 3D parts along with the overall deformation of the system, aiming to reach a very low percentage of between the true value (as an input parameter) and measure value (as an output parameter). 2. EXPERIMENTAL DETAILS AND METHODOLOGY The desktop FDM 3D printing machine used in this study is the BEAST from Cultivate3D, Australia (see Table I for basic technical details). The filament material used for model fabrication is advanced polylactic acid, PLA+, (esun PLA+

2 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:04 8 filament, advanced formula by added extra bio-polyesters blends), light blue coloured, 1.75 mm diameter and ±0.05 mm tolerance (Shenzhen Esun Industrial Co., Ltd.). It is made up of 100% bio-degradable polymers, derived from renewable sources (such as corn starch, sugarcane or tapioca roots) with the molecular formula (C 3H 4O 2) n. The major differences between PLA+ and regular PLA filaments are the elongation at the break points for PLA+ which is 29% whereas for regular PLA which is 5%. Besides, the Izod impact strength for PLA+ filament is 7 KJ/m 2 and for regular PLA filament is 4.2 KJ/m 2 [15]. Based on that, the toughness of advanced PLA+ filament material is superior than regular PLA. It is a widely used, costeffective, environmentally-friendly method for both household and workplace, and thermoplastic material for FMD 3D is used in rapid prototyping (RP) [16]. The PLA+ filament material possesses excellent mechanical properties, with elastic modulus (also known as the modulus of elasticity, (E) and tensile strength (TS) or ultimate tensile strength (UTS)) in the range of 3.2 to 3.7 GPa and 55 to 60 MPa, respectively [17]. A number of studies have recently reported the mechanical strength of different FDM 3D printed plastics as summarized in Table II [18-22]. These studies highlighted the fact that PLA+ filament material has a better mechanical response than other thermoplastic polymers investigated. The PLA+ filament material is a semi-crystalline polymer with a glass transition temperature of 65 C to 70 C. Its melting temperature is approximately 160 C up to 170 C and does not produce hazardous toxics [23]. Using advanced PLA+ filament materials for printing allows the modeling of sharper edges of the object with no risk of cracking or deformation [15, 24]. Main Features Technology Layer resolution XY positioning resolution Z positioning resolution Filament diameter Nozzle Diameter Material type File compatibility Printing weight Printing size (w d h) Total build volume TABLE I Basic technical parameters of the desktop 3D printing 4x synchronous printing, large build volume, high precision, LCD controller, SD card and USB printing FDM (Fused Deposition Modeling) <50 microns 6.25 microns 1.25 microns 1.75 mm 0.25 to 1.00 mm PLA, PLA+, ABS, PVC (all filament types available) STL and G-Code 30 Kg mm mm (single extruder configuration) mm (2x single extruder configuration) mm (4x single extruder configuration) Raster Angle TABLE II Mechanical response (tensile strength, MPa) of different thermoplastics filament, adapted from [18-22] FDM 3D Filament Materials ABS PP PC PLA PEI Polyether Imide Acrylonitrile Butadiene Styrene Polypropylene Polycarbonate Polylactic Acid A total of fourteen FDM 3D printed parts were built and examined in this study. All specimens were printed with a raster angle of +45 /-45 to the x-axis along with flat orientation. This orientation was selected instead of unidirectional orientation as a majority of the FDM 3D printed parts use an alternating raster pattern as the default printing scheme. Therefore, the data from this study will be directly relatable to the manufacturing of the FDM 3D printed parts. The experiment started with a 3D modeling design that was prepared by using CATIA solid 3D modeling software. CATIA solid 3D is worldwide software used in many industries, including construction, electronics, machinery, and aerospace. One of the really remarkable features of CATIA solid 3D software is the variety of workbenches in its mechanical design section, making the design parts produced unique. A 3D shape cuboid model (STL format file) was designed with a size of 5 mm in length, 30 mm in width and 100 mm in height as shown in Figure 1. The STL (STereo-Lithography) is a file format native to the STL (STereo-Lithography) computer-aided design (CAD) software created by 3D systems. Many other software packages support this STL format file; it is widely used for rapid prototyping and computer-aided manufacturing. Then, the digital model is converted into printing instruction of thin layers for the opensource FDM 3D printer by using for example Slic3r software [25] and this produces a G-Code (G-Programming Language) file containing the complete sets of instructions and commands to a specific 3D printer, which in turn controls the extrusion head of the FDM 3D printer and defines the precise motion control paths. The FDM 3D printer allows the G-Code file instructions to lay down successive layer-by-layer or path-bypath loaded raw material (PLA+ filament) through a circular nozzle to build the physical object from a series of thinly sliced horizontal cross-sections until the entire 3D object of the final shape is created. For each layer, the circular nozzle moves following a piece-wise linear path horizontally. The PLA+ filament material extruded along each line segment is

3 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:04 9 commonly deposited in layers. After the whole layer is deposited, either the circular nozzle or the printing platform shift vertically to print the next deposit. The benefit of this procedure is its capability to build almost any complex 3D shape feature. Fig. 1. 3D shape cuboid model with a pattern of PLA+ filament deposition in the layers of 3D printed standard test bar Figure 2 and Equation (1) show the methodology that is used in this investigation to measure the deformation. In this trial, the FDM 3D prints deformation was measured using the digital vernier height gauge. WD = Center Height Height (1) Where, WD represents the deformation in mm, center height represents the measured height between corners 1 and 4 (front) or the measured height between corners 2 and 3 (rear), and corner height represents the measured height at each corner in mm. To be more precise, to measure the deformation at each corner, Equation (1) can be rewritten for each corner as stated from Equation (2) to Equation (5): than 50 nm). For convenience, three calibration trials were carried out. The calibration results showed that the relationship between the input data (Slip Gauge dimension) and output data (reading in the digital vernier height gauge) was a linear relationship (R 2 > 0.999) with 99.7% level of confidence and coverage factor, k = 3. This result is adequate as these trials are predominantly about related behaviour; design interpretation to other systems is always vulnerable to variations in materials and dimensions. WD corner 1 = Front Height 1 (2) WD corner 2 = Rear Height 2 (3) WD corner 3 = Rear Height 3 (4) WD corner 4 = Front Height 4 (5) This method of measuring the deformation precisely, from Equation (2) to Equation (5) was used to avoid any misalignment in the 3D platform and also to prevent any uncertainty appearing in the actual value of the geometry and any that might appear in the first layer of building the 3D parts. Before conducting the height measurement (), a calibration procedure was performed. A calibration procedure was carried out for the digital vernier height gauge using standard rectangular block gauges (Slip Gauges) M112 (grade 0, tolerance ±0.04 µm) with a high degree of surface finish (less Fig. 2. deformation and its method of measurement at each corner 2.1. Process Parameters Selection After conducting a great many experimental trial runs, five different values of nozzle temperature and four different

4 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:04 10 printing speeds are taken into account as these were found to be the most influential process parameter on the building parts in FDM 3D printing technology. Each independent variable was studied individually and also by using the other independent parameter (e.g., printing speed) to validate the results. Table III shows the process parameters of the FDM 3D prints used during the investigation including the independent variables namely nozzle temperature and printing speed. TABLE III Process parameters selection for desktop FDM 3D printer Parameters Unit Values Nozzle Diameter mm 0.5 Nozzle Temperature C 180, 190, 200, 210, 220 Printing Speed mm/s 5, 10, 15, 20 Layer Height mm 0.2 Infill % 20 Type of material - PLA+ Extrude of material (layer width) mm 0.48 Speed for non-print moves mm/s 60 Horizontal shells (top and bottom layer) - zero Vertical shells - 1 Cooling Rate - build-in Bed temperature C Room Temperature Room temperature C 25±1 Relative Humidity % RH 40±5 3. FDM 3D FABRICATION The FDM 3D model (test bar) has been designed and fabricated as shown in Figure 3 including the deformation problem which appears after the cooling phase and is encircled in red. The parts have been constructed using PLA+ filament material with flat 45 /-45 build orientation. A total of ten 3D FDM parts were fabricated with nozzle temperature as an independent variable ranging from 180 C to 220 C at a constant printing speed of 15 mm/s, while another total of four 3D FDM parts were built with printing speed as an independent variable ranging from 5 mm/s to 20 mm/s at a constant nozzle temperature of 220 C. Fig. 3. The FDM 3D object. Warping deformation problem shown in the circles 4. RESULTS AND DISCUSSION The FDM 3D parts should be allowed to cool down to room temperature and then measured directly after they are removed from the platform. After the FDM 3D parts were built, the dimension of the test bar in each corner (1, 2, 3 and 4) is measured using the digital vernier height gauge. Each dimension (corner) is measured at least three times, and the average (mean) is considered. Deviation for each dimension (corner) of the test bar in a direction is calculated and presented as standard deviation (mean±sd). The for each corner and the overall is also considered. The experimental observations and the percentage deviations are discussed in the following section. All 3D samples taken in this trial have more or less deformation around each corner. For independent variable nozzle temperature, the data were analyzed using pair-sample t-test (ANOVA) to analyze batch variations using OriginLab 2017 software. All values were reported as the mean ± standard deviation (mean±sd) provides valuable results. For all results, p-values were determined and considered not significant if larger than 0.05 level of significance. In cases without thermos adhesive, the t-test and p-values were as follows; (t(27.8) = 4, p = at corner 1, (t(27.6) = 4, p = at corner 2, (t(27.4) = 4, p = at corner 3 and (t(27.5) = 4, p = at corner 4, respectively. In cases where thermos adhesive was added, the t- Test and p-values were as follows; (t(27.8) = 4, p = at corner 1, (t(28) = 4, p = at corner 2, (t(27.7) = 4, p = at corner 3 and (t(27.5) = 4, p = at corner 4, respectively. For independent variable speed printing, the data were analyzed using pair-sample t-test (ANOVA) to analyze batch variations using OriginLab 2017 software. All values were reported as the mean ± standard deviation (mean±sd) provides valuable results. For all results, p-values were determined and considered not significant if larger than 0.05 level of significance. In cases involving thermos adhesive, the t-test and p-values were as follows; (t(2.4) = 4, p = 0.1 at corner 1, (t(2.4) = 3, p = 0.1 at corner 2, (t(2.4) = 3, p = 0.1 at corner 3 and (t(2.4) = 3, p = 0.1 at corner 4, respectively. Table IV shows the center height of all FDM 3D parts at the front between corners 1 and 4 and the rear between corners 2 and 3 along with and without thermos adhesive including the

5 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:04 11 independent variable of nozzle temperature ranging from 180 C to 220 C. Table V shows the center height of all FDM 3D parts at the front between corners 1 and 4 and the rear between corners 2 and 3 along with only thermos adhesive including the independent variable of printing speed ranging from 5 mm/s to 20 mm/s. TABLE IV Center height of specimen (front and rear) at 15 mm/s printing speed Parts No. Nozzle without with Printing Time Temperature Total Height (mm) thermos adhesive thermos adhesive (minutes) ( C) Front Rear Front Rear TABLE V Center height of specimen (front and rear) at 220 C nozzle temperature Parts No. Printing Speed Printing Time with thermos adhesive Total Height (mm) (mm/s) (minutes) Front Rear Nozzle Temperature vs. Warping Deformation Referring to Table IV, Table VI shows deformation for the first five FDM 3D prints without adding thermos adhesive on the platform. Such a deformation is revealed in practice as bending of the FDM 3D part in the direction away from the print pad (the U-shaped object). In this trial, the nozzle temperature ranges from 180 C to 220 C. 1 represents the starting point whereas corner 4 represents the finishing point. As can be seen from Table VI, the FDM 3D print part 1 with a nozzle temperature of 220 C shows the lowest deformation of 4.40±0.15 mm with an overall of 12.05%. It also indicated that the highest deformation was 3.98±0.25 mm with overall of 20.45% for printed part 2 with a nozzle temperature of 190 C. On the other hand, corner 1 (printed part 4) reported the lowest deformation of 4.47 mm with 10.6% (at 210 C nozzle temperature) whereas corner 4 (printed part 4) reported the highest deformation of 3.51 mm with 29.8% (at 210 C nozzle temperature). The may occur due to the temperature gradient during the cooling down phase, and solidification or as uneven heat distribution creates internal stresses within a part. The inhomogeneous heat dissipation, with a more significant effect in massive objects, causes high internal tensions in the material (e.g., PLA+ filament material) induced due to changes in the PLA+ filament density, as the PLA+ filament material is transformed from a melting state phase to a solid state phase. Printing at a lower nozzle temperature (around 180 C), even if it is excellent for avoiding or, at least, minimizing the drawback of deformation, is not always considered feasible. This is because the 3D printer will take a long time to complete the whole printing path of those layers, the lowest nozzle temperature required for allowing an excellent PLA+ interlayer adhesion is not maintained. Entirely insulated and closed chambers are key to avoiding variations in temperature, and so minimizing these uncontrollable issues, both deformation, and interlayer adhesion. Referring to Table V, Table VII shows the deformation for another new five FDM 3D prints. The PLA+ plastic filament is implemented by the nozzle to the print pad with the implemented thermos adhesive. The adhesive is to certain degree melted by the plastic (it depends on the speed with which the nozzle is moved), and it partially covers the plastic filament. The contact area of the object and the print pad is then larger, and the power caused by the tendency to deformation of the object is better distributed on its surface. The nozzle temperature ranging from 180 C to 220 C. 1 represents the starting point whereas corner 4 represents the finishing point. As can be seen from Table VII, the FDM 3D print part 5 with a nozzle temperature of 220 C shows the lowest deformation of 4.77±0.12 mm with an overall of 4.55%. It also indicates that the highest deformation was 4.56±0.25 mm with overall of 8.85% for printed part 1 with nozzle temperature of 180 C. On the other hand, corner 1 (printed part 5) reported the lowest deformation of 4.90 mm with 2.00% (at 220 C nozzle temperature) whereas corner 3 (printed part 1) and corner 4 (printed part 4) reported the highest deformation of 4.51 mm with 9.80% (at 180 C and 210 C nozzle temperature, respectively). Figure 4 shows the deformation with and without thermos adhesive as the results of data output in Table VI and VII. It shows clearly that the deviation for model one (without thermos adhesive) was in a range from ±0.15 to ±0.42 mm. With thermos adhesive, the deviation shows best results in a range from ±0.06 to ±0.25 mm. The positive finding is a reasonable function of thermos adhesive. The PLA+ filament laid by the nozzle melts the small layer of thermos adhesive on the print pad. This way, the contact area between the PLA+ plastic filament and the pad is increased, and the possibility of separation of the FDM 3D object from the pad during the printing process is decreased. In practice, a heated pad is necessary to eliminate the deformation of the part during its FDM 3D printing

6 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:04 12 [26]. If the platform (print bed) is cooler than the melting temperature point and softening temperature point of the PLA+ filament plastic, the filament strands will solidify on the platform (print bed) and form the printed FDM 3D object. Typically, the plastics solidification results in a huge drop in volume ( deformation) followed by additional thermal contraction of the cold layer as the temperature drops gradually below solidification (freezing) temperature point. The net effect of these phenomena is a reduction in the size of the FDM 3D Parts No. Nozzle Temperature ( C) Total Height (mm) corner 1 printed object compared to the true value that was laid down on the platform (print bed). This could result in deformation. However, this paper proved that the use of PLA+ filament material with thermos adhesive (no heated pad) had got a positive effect on the quality of printed FMD 3D object by reaching 2.0% at corner 1 and 4.55% overall for FDM 3D printed part 1 and nozzle temperature at 220 C and 15 mm/s printing speed. TABLE VI Warping deformation without thermos adhesive Deflected Height / Warping Deformation (mm) corner 2 corner 3 corner 4 Mean±SD ± ± ± ± ± Parts No. Nozzle Temperature ( C) Total Height (mm) 1 TABLE VII Warping deformation with thermos adhesive Deflected Height / Warping Deformation (mm) Mean±SD ± ± ± ± ± overall overall 220 C 180 C 5.0 true value corner 1 corner 2 corner 3 corner 4 (a) 190 C 220 C 180 C 5.0 true value corner 1 corner 2 corner 3 corner 4 (b) 190 C increased increased decreased decreased 210 C 200 C 210 C 200 C 5.0 mm No deformation 5.0 mm deformation presents 5.0 mm No deformation 5.0 mm deformation presents Fig. 4. Warping deformation (a) without thermos adhesive and (b) with thermos adhesive Figures 5 and 6 show the contour plot of all corners which respond to the independent variable nozzle temperature. The interval of nozzle temperatures started from 180 C and was successively increased by 100 C up to 220 C. It shows a different view of the correlation between adjacent corners 1 and 4 and corners 2 and 3 in respect to nozzle temperature. It shows

7 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:04 13 that the best result of minimum deformation value happens between corner 1 and 4 with using thermos adhesive of the blue coloured circle comparing to others at nozzle temperature equal to 220 C. On the other hand, as referred to the plot of nozzle temperature versus corner 1 and 4 without thermos adhesive, it shows that the greatest results of deformation in between the set of 190 C and 220 C and 20% infill density at an angular position of about 45. This result shows that the platform needs a thermos adhesive to reduce the deformation and also result in the best 3D printing quality. Generally, the starting point (corner 1) and end point (corner 4) represent the lowest deformation in all cases. On the other hand, corners 2 and 3 represent the highest deformation (the U-shaped object) in all cases due to PLA+ filament material transformation from melting phase to solid phase. This applies even for an unfinished object. So, the dimension (particularly the height between corners 2 and 3) of the FDM 3D printed parts does not tally with the physical dimensions given by the computer pattern. Although, deformation is not an exclusive drawback of AM as it must be also taken into account when components are produced by many other manufacturing techniques, such as casting or welding. So, optimizing nozzle temperature or, as will be seen in the follwing section, optimizing the printing speed can partially avoid this issue. Fig. 6. Contour plot of (a) corner 1 and 4 (b) corner 2 and 3 corresponded to the nozzle temperature with thermos adhesive at 15 mm/s printing speed Fig. 5. Contour plot of (a) corner 1 and 4 (b) corner 2 and 3 corresponded to the nozzle temperature without thermos adhesive at 15 mm/s printing speed 4.2. Printing Speed vs. Warping Deformation Once the optimization is completed as discussed before, the results need to be validated. For this purpose, the test bar as shown in Figure 1 is again printed with the optimal parameter of nozzle temperature of 220 C and measured for deformation. The result of the validation process shows that there is a significant improvement in deformation in each case. Fortunately, corners 1 and 4 improved significantly at 20 mm/s when using thermos adhesive and other corners not so much. Table VIII shows the deformation for four new FDM 3D prints at a constant nozzle temperature of 220 C and independent printing speed of 5, 10, 15 and 20 mm/s. The PLA+ plastic filament is implemented by the nozzle to the print pad with the implemented thermos adhesive. As can be seen from Table VIII, the FDM 3D print part 1 with a printing speed of 5 mm/s shows the lowest deformation of 4.87±0.10 mm with an overall of 2.60%. It also shows that the highest deformation was 4.77±0.12 mm with an overall of 4.55% for the printed part 3 with a printing speed of 15 mm/s. On the other hand, corner 1 (printed part 4) reported the lowest deformation of 4.98 mm with 0.4% (at 20 mm/s printing speed) whereas corner 3 (printed part 3) reported the highest deformation of 4.62 mm with 7.6% (at 15 mm/s printing speed).

8 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:04 14 It should be noted that printing speed at 5 mm/s and 220 C nozzle temperature shows less deformation at corner 1 (starting path) and corner 4 (ending path) with an of 1.4% and 1.0%, respectively. However, this does not necessarily mean that additive processes are cost-effective or a profitable investment at this printing speed as the universal approach is a time-driven activity-based costing, in which the costs of the processes are determined by the time they require to be accomplished. Here, the printing time to complete the whole FDM 3D object was 60 minutes at 5 mm/s printing speed while it takes 16 minutes at 20 mm/s printing speed to complete the FDM 3D part with thermos adhesive. The time required for printing one model is one of the most significant aspects for its final price, so machine type, layers thickness, the distance between points in the part or printing speed are some of the most sensitive technology factors and strongly influence the manufacturing costs. Having this in mind, 0.4% and 0.8% were reached at 20 mm/s printing speed and 220 C for corner 1 (starting path) and corner 4 (ending path), respectively. Parts No. Printing Speed (mm/s) Total Height (mm) 1 TABLE VIII Warping deformation with thermos adhesive at 220 C nozzle temperature Deflected Height / Warping Deformation (mm) Mean±SD overall ± ± ± ± Figure 7 shows the deformation with thermos adhesive as the results of Table VIII. It shows clearly that with thermos adhesive; the standard deviation (±SD) shows best results in a range from ±0.06 to ±0.12 mm. The positive finding is a reasonable function of thermos adhesive. The general trend shows that printing speed with 20 mm/s and 220 C nozzle temperature reported less deformation at corner 1 (starting point) and corner 4 (ending point). However, it also shows that printing with 20 mm/s reported high deformation at corner 2. It is possible to partially avoid at a specific corner (e.g., corner 2) by adding in the design discs (mouse ears) or little square boxes in the corner. These little one-layer disks or boxes keep warm the zone they are attached to for a given period and indeed contribute to generating an extra structure preventing deformation, and they can be simply trimmed after the cooling phase. 20 mm/s 5 mm/s 5.00 true value mm/s decreased increased corner 1 corner 2 corner 3 corner 4 10 mm/s 5.0 mm No deformation 5.0 mm deformation presents Fig. 7. Warping deformation with thermos adhesive at different printing speed and 220 C nozzle temperature Figure 8 shows the contour plot of all corners which respond to the independent variable printing speed. It shows that the best result of minimum deformation value happens between corner 1 and 4 when using thermos adhesive compared to others at a nozzle temperature equal to 220 C, 20 mm/s printing speed and 20% infill density, resulting in the best 3D printing quality. corner contour plot of printing speed vs. corner 1 and corner corner 4 center height represents the measured height between corner 1 and 4 (front) corner contour plot of printing speed vs. corner 2 and corner corner 3 Fig. 8. Contour plot of (a) corner 1 and 4 (b) corner 2 and 3 corresponded to the printing speed with thermos adhesive at 220 C nozzle temperature center height represents the measured height between corner 2 and 3 (rear) (a) Printing Sped < > 20.0 with thermos adhesive (b) Printing Sped < > 20.0 with thermos adhesive

9 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No: CONCLUSIONS This article presents the results of research in the field of prototyping, FDM 3D parts. All specimens were produced using an FDM 3D printer from a single spool of PLA+ filament. The 3D printer performs hot extrusion of a PLA+ filament with an initial diameter of 1.75 mm through a circular nozzle with a diameter of 0.5 mm. The extruded PLA+ filament is deposited onto the non-heated platform by moving a printing head in a user-defined pattern, such as to achieve the desired final 3D shape. It is concluded that the optimum value for the nozzle temperature was 220 C with minimum deformation of 4.77±0.12 mm at 15 mm/s printing speed. The accuracy of optimization resulted in some small percentages of of 4.55%. The result of the validation process shows that there is a significant improvement in deformation in each case by reaching 0.4%. 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