scholarly journals Modeling of the Influence of Input AM Parameters on Dimensional Error and Form Errors in PLA Parts Printed with FFF Technology

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4152
Author(s):  
Carmelo J. Luis-Pérez ◽  
Irene Buj-Corral ◽  
Xavier Sánchez-Casas
Keyword(s):  
Surface Roughness ◽  
Process Parameters ◽  
Desirability Function ◽  
Nozzle Diameter ◽  
Simultaneous Optimization ◽  
Acetabular Cup ◽  
Fused Filament Fabrication ◽  
Dimensional Error ◽  
Layer Height ◽  
Form Errors

As is widely known, additive manufacturing (AM) allows very complex parts to be manufactured with porous structures at a relatively low cost and in relatively low manufacturing times. However, it is necessary to determine in a precise way the input values that allow better results to be obtained in terms of microgeometry, form errors, and dimensional error. In an earlier work, the influence of the process parameters on surface roughness obtained in fused filament fabrication (FFF) processes was analyzed. This present study focuses on form errors as well as on dimensional error of hemispherical cups, with a similar shape to that of the acetabular cup of hip prostheses. The specimens were 3D printed in polylactic acid (PLA). Process variables are nozzle diameter, temperature, layer height, print speed, and extrusion multiplier. Their influence on roundness, concentricity, and dimensional error is considered. To do this, adaptive neuro-fuzzy inference systems (ANFIS) models were used. It was observed that dimensional error, roundness, and concentricity depend mainly on the nozzle diameter and on layer height. Moreover, high nozzle diameter of 0.6 mm and high layer height of 0.3 mm are not recommended. A desirability function was employed along with the ANFIS models in order to determine the optimal manufacturing conditions. The main aim of the multi-objective optimization study was to minimize average surface roughness (Ra) and roundness, while dimensional error was kept within the interval Dimensional Error≤0.01. When the simultaneous optimization of both the internal and the external surface of the parts is performed, it is recommended that a nozzle diameter of 0.4 mm be used, to have a temperature of 197 °C, a layer height of 0.1 mm, a print speed of 42 mm/s, and extrusion multiplier of 94.8%. This study will help to determine the influence of the process parameters on the quality of the manufactured parts.

scholarly journals Effect of Printing Parameters on Dimensional Error, Surface Roughness and Porosity of FFF Printed Parts with Grid Structure

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1213
Author(s):  
Irene Buj-Corral ◽  
Ali Bagheri ◽  
Maurici Sivatte-Adroer
Keyword(s):  
Flow Rate ◽  
Desirability Function ◽  
Low Cost ◽  
Multi Objective Optimization ◽  
Grid Structure ◽  
Fused Filament Fabrication ◽  
Dimensional Error ◽  
Layer Height ◽  
Multi Objective ◽  
Printing Parameters

Extrusion printing processes allow for manufacturing complex shapes in a relatively cheap way with low-cost machines. The present study analyzes the effect of printing parameters on dimensional error, roughness, and porosity of printed PLA parts obtained with grid structure. Parts are obtained by means of the fused filament fabrication (FFF) process. Four variables are chosen: Layer height, temperature, speed, and flow rate. A two-level full factorial design with a central point is used to define the experimental tests. Dimensional error and porosity are measured with a profile projector, while roughness is measured with a contact roughness meter. Mathematical regression models are found for each response, and multi-objective optimization is carried out by means of the desirability function. Dimensional error and roughness depend mainly on layer height and flow rate, while porosity depends on layer height and printing speed. Multi-objective optimization shows that recommended values for the variables are layer height 0.05 mm, temperature 195 ºC, speed 50 mm/min, and flow rate 0.93, when dimensional error and roughness are to be minimized, and porosity requires a target value of 60%. The present study will help to select appropriate printing parameters for printing porous structures such as those found in prostheses, by means of extrusion processes.

scholarly journals Analysis and optimization of laser drilling process during machining of AISI 303 material using grey relational analysis approach

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
V. Chengal Reddy ◽  
Thota Keerthi ◽  
T. Nishkala ◽  
G. Maruthi Prasad Yadav
Keyword(s):  
Surface Roughness ◽  
Process Parameters ◽  
Grey Relational Analysis ◽  
Pulse Frequency ◽  
Laser Drilling ◽  
Simultaneous Optimization ◽  
Fibre Laser ◽  
Drilling Process ◽  
Relational Analysis ◽  
Grey Relational

AbstractSurface roughness and heat-affected zone (HAZ) are the important features which influence the performance of the laser-drilled products. Understanding the influence of laser process parameters on these responses and identifying the cutting conditions for simultaneous optimization of these responses are a primary requirement in order to improve the laser drilling performance. Nevertheless, no such contribution has been made in the literature during laser drilling of AISI 303 material. The aim of the present work is to optimize the surface roughness (Ra) and HAZ in fibre laser drilling of AISI 303 material using Taguchi-based grey relational analysis (GRA). From the GRA methodology, the recommended optimum combination of process parameters is flushing pressure at 30 Pa, laser power at 2000 W and pulse frequency at 1500 Hz for simultaneous optimization of Ra and HAZ, respectively. From analysis of variance, the pulse frequency is identified as the most influenced process parameters on laser drilling process performance.

scholarly journals Comparative study of the flexural properties of ABS, PLA and a PLA–wood composite manufactured through fused filament fabrication

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
J.A. Travieso-Rodriguez ◽  
R. Jerez-Mesa ◽  
Jordi Llumà ◽  
Giovanni Gomez-Gras ◽  
Oriol Casadesus
Keyword(s):  
Additive Manufacturing ◽  
Acrylonitrile Butadiene Styrene ◽  
Nozzle Diameter ◽  
Bending Test ◽  
Mechanical Resistance ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Layer Height ◽  
Maximum Deformation ◽  
Materials Used

Purpose The aim of this paper is to analyze the mechanical properties of acrylonitrile-butadiene-styrene (ABS) parts manufactured through fused filament fabrication and compare these results to analogous ones obtained on polylactic acid (PLA) and PLA–wood specimens to contribute for a wider understanding of the different materials used for additive manufacturing. Design/methodology/approach With that aim, an experimental based on an L27 Taguchi array was used to combine the specific parameters taken into account in the study, namely, layer height, nozzle diameter, infill density, orientation and printing velocity. All samples were subjected to a four-point bending test performed according to the ASTM D6272 standard. Findings Young’s modulus, elastic limit, maximum stress and maximum deformation of every sample were computed and subjected to an analysis of variance. Results prove that layer height and nozzle diameter are the most significant factors that affect the mechanical resistance in pieces generated through additive manufacturing and subjected to bending loads, regardless of the material. Practical implications The best results were obtained by combining a layer height of 0.1 mm and a nozzle diameter of 0.6 mm. The comparison of materials evidenced that PLA and its composite version reinforced with wood particles present more rigidity than ABS, whereas the latter can experience further deflection before break. Originality/value This study is of interest for manufacturers that want to decide which is the best material to be applied for their application, as it derives in a practical technical recommendation of the best parameters that should be selected to treat the material during the fused filament fabrication process.

scholarly journals The Impact of 3D Printing Process Parameters on the Dielectric Properties of High Permittivity Composites

Designs ◽  
2019 ◽  
Vol 3 (4) ◽  
pp. 50 ◽  
Author(s):  
Athanasios Goulas ◽  
Shiyu Zhang ◽  
Darren A. Cadman ◽  
Jan Järveläinen ◽  
Ville Mylläri ◽  
...  
Keyword(s):  
3D Printing ◽  
Process Parameters ◽  
Relative Permittivity ◽  
Main Process ◽  
Fused Filament Fabrication ◽  
Layer Height ◽  
Additive Manufacturing Technology ◽  
The Impact ◽  
Printing Speed ◽  
Hatch Spacing

Fused filament fabrication (FFF) is a well-known and greatly accessible additive manufacturing technology, that has found great use in the prototyping and manufacture of radiofrequency componentry, by using a range of composite thermoplastic materials that possess superior properties, when compared to standard materials for 3D printing. However, due to their nature and synthesis, they are often a great challenge to print successfully which in turn affects their microwave properties. Hence, determining the optimum printing strategy and settings is important to advance this area. The manufacturing study presented in this paper shows the impact of the main process parameters: printing speed, hatch spacing, layer height and material infill, during 3D printing on the relative permittivity (εr), and loss tangent (tanδ) of the resultant additively manufactured test samples. A combination of process parameters arising from this study, allowed successful 3D printing of test samples, that marked a relative permittivity of 9.06 ± 0.09 and dielectric loss of 0.032 ± 0.003.

Process–Property Relationships for Fused Filament Fabrication on Preexisting Polymer Substrates

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Harry A. Pierson ◽  
Bharat Chivukula
Keyword(s):  
Surface Roughness ◽  
Bond Strength ◽  
Layer Thickness ◽  
Process Parameters ◽  
Optimal Parameter ◽  
Fused Filament Fabrication ◽  
Highly Sensitive ◽  
Raster Angle ◽  
Process Property ◽  
Five Axis

Recent advances in fused filament fabrication (FFF), such as five-axis printing, patching existing parts, and certain hybrid manufacturing processes, involve printing atop a previously manufactured polymer substrate. The success of these technologies depends upon the bond strength between the substrate and the newly added geometry. ANOVA and response surface methods were used to determine the effect of three process parameters on bond tensile strength: surface roughness, layer thickness, and raster angle. Experimental results indicate that the process–property relationships are not identical to those found in single, continuous FFF operations, and that the physical bonding mechanisms may also be different. Bond strength was found to be highly sensitive to surface roughness and layer thickness, and distinct optimal parameter settings exist. These results represent a first step toward understanding bond strength in such circumstances, allowing manufacturers to intelligently select process parameters for the production of both the substrate and the secondary geometry.

scholarly journals Effect of Printing Parameters on Dimensional Error and Surface Roughness Obtained in Direct Ink Writing (DIW) Processes

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2157
Author(s):  
Irene Buj-Corral ◽  
Alejandro Domínguez-Fernández ◽  
Ana Gómez-Gejo
Keyword(s):  
Desirability Function ◽  
Roughness Parameter ◽  
Ceramic Materials ◽  
Machining Processes ◽  
Dimensional Error ◽  
Hip Prostheses ◽  
Layer Height ◽  
Direct Ink Writing ◽  
Bed Temperature ◽  
Printing Speed

Prostheses made from ceramic materials have the advantages of producing little debris and having good durability, compared with those made from metal and plastic. For example, hip prostheses require a porous external area that allows their fixation by means of osseointegration and a solid internal area that will be in contact with the femoral head. The manufacturing of complex ceramic shapes, by means of machining processes, for example, is complicated and can lead to breakage of the parts because of their fragility. The direct ink writing (DIW) process allows the printing of ceramic pastes into complex shapes that achieve their final strength after a heat treatment operation. This paper studies both the dimensional error and surface finish of porous zirconia prismatic parts prior to sintering. The variables considered are infill, layer height, printing speed, extrusion multiplier and bed temperature. The responses are the dimensional error of the lateral walls of the samples and an areal roughness parameter, the arithmetical mean height, Sa. Mathematical models are found for each response, and multiobjective optimization is carried out by means of the desirability function. The dimensional error depends mainly on the interaction between layer height and infill, while the roughness on the interaction between infill and printing speed. Thus, infill is an important factor for both responses. In the future, the behavior of compact printed parts will be addressed.

scholarly journals Dimensional Stability of 3D Printed Parts: Effects of Process Parameters

2019 ◽  
Vol 119 (2) ◽  
pp. 9 ◽  
Author(s):  
Elizabeth Azhikannickal ◽  
Aaron Uhrin
Keyword(s):  
3D Printing ◽  
Process Parameters ◽  
Dimensional Stability ◽  
Computer Aided Design ◽  
3D Model ◽  
Dimensional Error ◽  
Layer Height ◽  
Fused Deposition ◽  
3D Printed ◽  
Rms Error

The three-dimensional (3D) printing manufacturing process begins with the creation of a 3D model—using computer aided design (CAD) software—of the part to be printed. Using a type of 3D printing known as fused deposition modeling (FDM®), the 3D printer extrudes molten plastic to scan lines to create individual layers (i.e., the infill): one on top of the other. (Note that "scan" in this context refers to the movement of the extruder head, along an x,y coordinate path, while depositing molten plastic.) This process is repeated until the overall geometry, specified by the 3D model, is built. This process is attractive for producing proof of concept or prototype parts in various fields including automotive, aerospace, and medical. However, FDM subjects the material to rapid heating and cooling; therefore, some degree of undesirable warpage of the part occurs post fabrication. The primary objective of this study was to determine the effect of 4 process parameters (i.e., infill shape, infill density, number of perimeters created per layer, and layer height) on the total dimensional error of a representative 3D-printed part. This part (the "simple part"), used in Trials 1 through 3 of this study, was a square acrylonitrile butadiene styrene (ABS) plate having a nominal measurement of 50 mm × 50 mm × 5 mm thick. A residual error (the difference between the measured post-printing dimension and the theoretical CAD file dimension) was calculated along each given direction and for each test print. Finally, a root mean square (RMS) error (i.e., the square root of the average of the squared residual errors along the length, width, and thickness directions) was calculated for each printed part. Three repeat test prints were carried out for each parameter. The number of perimeters played a key role in the dimensional stability of the part. As the number of perimeters increased up to 5, the RMS error decreased. Beyond 5 perimeters, however, the RMS error increased due to excessive warpage/curvature at the corners of the part. Ultimately, when examined individually, a grid infill shape at 100% density, a 0.4 mm layer height, and 5 perimeters each produced the lowest warpage. In combination, these same 4 parameters also produced the lowest RMS error (based on dimensional analysis of 3 test prints) when used to print a more complicated part (the "stacked part") in Trial 4.

scholarly journals Mathematical Modeling and Optimization of Fused Filament Fabrication (FFF) Process Parameters for Shape Deviation Control of Polyamide 6 Using Taguchi Method

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3697
Author(s):  
Zohreh Shakeri ◽  
Khaled Benfriha ◽  
Mohammadali Shirinbayan ◽  
Mohammad Ahmadifar ◽  
Abbas Tcharkhtchi
Keyword(s):  
Product Development ◽  
Process Parameters ◽  
Optimization Method ◽  
Polyamide 6 ◽  
Wall Layer ◽  
Layer By Layer ◽  
Fused Filament Fabrication ◽  
Taguchi Optimization ◽  
Shape Deviation ◽  
Layer Height

Fused filament fabrication (FFF) is a layer-by-layer additive manufacturing (AM) process for producing parts. For industries to gain a competitive advantage, reducing product development cycle time is a basic goal. As a result, industries’ attention has turned away from traditional product development processes toward rapid prototyping techniques. Because different process parameters employed in this method significantly impact the quality of FFF manufactured parts, it is essential to optimize FFF process parameters to enhance component quality. The paper presents optimization of fused filament fabrication process parameters to improve the shape deviation such as cylindricity and circularity of 3D printed parts with the Taguchi optimization method. The effect of thickness, infill pattern, number of walls, and layer height was investigated as variable parameters for experiments on cylindricity and circularity. The MarkForged® used Nylon White (PA6) to create the parts. ANOVA and the S/N ratio are also used to evaluate and optimize the influence of chosen factors. As a result, it was concluded that the hexagonal infill pattern, the thickness of 5 mm, wall layer of 2, and a layer height of 1.125 mm were known to be the optimal process parameters for circularity and cylindricity in experiments. Then a linear regression model was created to observe the relationship between the control variables with cylindricity and circularity. The results were confirmed by a confirmation test.

Influence law and optimization analysis of technological parameters of TC4 titanium alloy on water cavitation peening

2021 ◽  
pp. 095440542110410
Author(s):  
Fuzhu Li ◽  
Jun Guo ◽  
Shangshuang Chen ◽  
Yuqin Guo ◽  
Ruitao Li ◽  
...  
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Titanium Alloy ◽  
Process Parameters ◽  
Nozzle Diameter ◽  
Main Process ◽  
Strengthening Effect ◽  
Surface Residual Stress ◽  
Influence Of Process Parameters ◽  
Tc4 Titanium Alloy

TC4 titanium alloy is widely used in aerospace, petrochemical, pharmaceutical and other fields, which accounts for about 60% of the current titanium alloy products. Water Cavitation Peening (WCP) is a new material surface modification process and has great development potential. The improvement of the water cavitation peening is severely limited by the correlation and coupling between process parameters. Therefore, the influence law of each process parameter is the key problem that needs to be resolved. TC4 titanium alloy as research object is took and four main process parameters of WCP under four working conditions is construct (four factors and four levels orthogonal). The influence of process parameters on three evaluation indexes is studied, such as the surface residual stress, the surface roughness and the microhardness. Then, the fuzzy mathematics comprehensive evaluation is used to optimize. Results show that the peening time has the greatest influence on strengthening effect and the nozzle diameter has the least. The optimized combination is that the nozzle diameter is 1.4 mm, the incident pressure is 40 MPa, the dimensionless target distance is 72.5 and peening time is 27.5 min. The corresponding surface residual stress, the surface roughness and the microhardness can reach −612 MPa, 0.76 μm, and 405 HV respectively.

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