Dimensional accuracy of FDM-printed polymer parts

2019 ◽  
Vol 26 (2) ◽  
pp. 288-298 ◽  
Author(s):  
Oğuzhan Emre Akbaş ◽  
Onur Hıra ◽  
Sahar Zhiani Hervan ◽  
Shahrad Samankan ◽  
Atakan Altınkaynak

Purpose This paper aims to analyze experimentally and numerically the effect of the nozzle temperature and feed rates on the dimensions of the fused deposition modeling (FDM) polymer parts. Design/methodology/approach In total, 30 strips per sample were printed with the same width as the nozzle diameter. The strips were printed with one vertical movement of the nozzle head. The width of the strips was measured with a caliper at five locations. A linear regression model was created based on the experimental data to understand the correlation between the strip width deviation and the parameters of interest. Numerical simulations were performed to predict the swell of the polymer exiting the nozzle using finite element method combined with level set method. The experimental results were then used to validate the models. Findings The average accuracy of polylactic acid (PLA) samples was better than that of acrylonitrile butadiene styrene (ABS) samples. The average strip width had a tendency to increase with increasing temperature for PLA samples, whereas ABS samples showed mixed behavior. The strip width decreased with increasing feed rate for most cases. The measurement positions had a major effect on strip width when compared to nozzle temperature and feed rate. The numerical model predictions were in good agreement with the experimental data. A few discrepancies were observed at high feed rates and nozzle temperatures. Originality/value This study will contribute to gaps in knowledge regarding the effect of processing conditions on dimensional accuracy of FDM-printed parts. The developed numerical model can be efficiently used to predict the dimensional accuracy of FDM-printed parts.

2021 ◽  
Vol 27 (11) ◽  
pp. 1-12
Author(s):  
Giovanni Gómez-Gras ◽  
Marco A. Pérez ◽  
Jorge Fábregas-Moreno ◽  
Guillermo Reyes-Pozo

Purpose This paper aims to investigate the quality of printed surfaces and manufacturing tolerances by comparing the cylindrical cavities machined in parts obtained by fused deposition modeling (FDM) with the holes manufactured during the printing process itself. The comparison focuses on the results of roughness and tolerances, intending to obtain practical references when making assemblies. Design/methodology/approach The experimental approach focuses on the comparison of the results of roughness and tolerances of two manufacturing strategies: geometric volumes with a through-hole and the through-hole machined in volumes that were initially printed without the hole. Throughout the study, both alternates are explained to make appropriate recommendations. Findings The study shows the best combinations of technological parameters, both machining and three-dimensional printing, which have been decisive for obtaining successful results. These conclusive results allow enunciating recommendations for use in the industrial environment. Originality/value This paper fulfills an identified need to study the dimensional accuracy of the geometries obtained by additive manufacturing, as no experimental evidence has been found of studies that directly address the problem of the FDM-printed part with geometric and dimensional tolerances and desirable surface quality for assembly.


Author(s):  
Fabian Lischke ◽  
Andres Tovar

One of the primary challenges faced in Additive Manufacturing (AM) is reducing the overall cost and printing time. A critical factor in cost and time reduction is post-processing of 3D printed (3DP) parts, of which removing support structures is one of the most time consuming steps. Support is needed to prevent the collapse of the part or certain areas under its own weight during the 3D printing process. Currently, the design of self-supported 3DP parts follows a set of empirical guide lines. A trial and error process is needed to produce high quality parts by Fused Depositing Modeling (FDM). The usage of chamfer angle with a max 45° angle form the horizontal for FDM is a common example. Inclined surfaces with a smaller angle are prone to defects, however no theoretical basis has been fully defined, therefore a numerical model is needed. The model can predict the problematic areas at a print, reducing the experimental prints and providing a higher number of usable parts. Physical-based models have not been established due to the generally unknown properties of the material during the AM process. With simulations it is possible to simulate the part at different temperatures with a variety of other parameters that have influence on the behavior of the model. In this research, analytic calculations and physical tests are carried out to determine the material properties of the thermoplastic polymer Acrylonitrile - Butadiene - Styrene (ABS) f or FDM at the time of extrusion. This means that the ABS is going to be extruded at 200°C to 245°C and is a viscous material during part construction. Using the results from the physical and analytical models, i.e., Timoshenko’s modified beam theory for micro-structures, a numerical material model is established to simulate the filament deformation once it is deposited onto the part. Experiments were also used to find the threshold for different geometric specifications, which could then be applied to the numerical model to improve the accuracy of the simulation. The result of the finite element analysis is compared to experiments to show the correlation between the prediction of deflection in simulation and the actual deflection measured in physical experiments. A case study was conducted using an application that optimizes topology of complex geometries. After modeling and simulating the optimized part, areas of defect and errors were determined in the simulation, then verified and and measured with actual 3D prints.


2017 ◽  
Vol 23 (2) ◽  
pp. 414-422 ◽  
Author(s):  
Timothy J. Coogan ◽  
David Owen Kazmer

Purpose The purpose of this paper is to investigate the factors governing bond strength in fused deposition modeling (FDM) compared to strength in the fiber direction. Design/methodology/approach Acrylonitrile butadiene styrene (ABS) boxes with the thickness of a single fiber were made at different platform and nozzle temperatures, print speeds, fiber widths and layer heights to produce multiple specimens for measuring the strength. Findings Specimens produced with the fibers oriented in the tensile direction had 95 per cent of the strength of the constitutive filament. Bond strengths ranged from 40 to 85 per cent of the filament strength dependent on the FDM processing conditions. Diffusion, wetting and intimate contact all separately affect bond strength. Practical implications This study provides processing recommendations for producing the strongest FDM parts. The needs for higher nozzle temperatures and more robust feed motors are described; these recommendations can be useful for companies producing FDM products as well as companies designing FDM printers. Originality/value This is the first study that discusses wetting and intimate contact separately in FDM, and the results suggest that a fundamental, non-empirical model for predicting FDM bond strength can be developed based on healing models. Additionally, the role of equilibration time at the start of extrusion as well as a motor torque limitation while trying to print at high speeds are described.


2020 ◽  
Vol 40 (5) ◽  
pp. 745-754
Author(s):  
Gurpartap Singh ◽  
Rupinder Singh ◽  
S.S. Bal

Purpose The purpose of this study is to investigate dimensional accuracy (Δd), surface roughness (Ra) and micro hardness (HV) of partial dentures (PD) prepared with synergic combination of fused deposition modelling (FDM) assisted chemical vapour smoothing (CVS) patterns and conventional dental casting (DC) from multi-factor optimization view point. Design/methodology/approach The master pattern for PD was prepared with acrylonitrile butadiene styrene (ABS) thermoplastic on FDM set-up (one of the low cost additive manufacturing process) followed by CVS process. The final PD as functional prototypes was casted with nickel–chromium-based (Ni-Cr) alloy by varying Ni% (Z). The other input parameters were powder to water ratio P/W (X) and pH value (Y) of water used. Findings The results of this study suggest that for controlling the Δd and Ra of the PD, most important factor is X, followed by Z. For hardness of PD, the most important factor is Z. But from overall optimization viewpoint, the best settings are X-100/12, Y-10 and Z-61% (in Ni-Cr alloy). Further, based upon X-bar chart (for HV), the FDM-assisted DC process used for preparation of PD is statistically controlled. Originality/value This study highlights that PD prepared with X-100/12, Y-10 and Z-61% gives overall better results from multi-factor optimization view point. Finally, X-bar chart has been plotted to understand the statistical nature of the synergic combination of FDM, CVS and DC.


2015 ◽  
Vol 21 (3) ◽  
pp. 250-261 ◽  
Author(s):  
Brian N. Turner ◽  
Scott A Gold

Purpose – The purpose of this paper is to critically review the literature related to dimensional accuracy and surface roughness for fused deposition modeling and similar extrusion-based additive manufacturing or rapid prototyping processes. Design/methodology/approach – A systematic review of the literature was carried out by focusing on the relationship between process and product design parameters and the dimensional and surface properties of finished parts. Methods for evaluating these performance parameters are also reviewed. Findings – Fused deposition modeling® and related processes are the most widely used polymer rapid prototyping processes. For many applications, resolution, dimensional accuracy and surface roughness are among the most important properties in final parts. The influence of feedstock properties and system design on dimensional accuracy and resolution is reviewed. Thermal warping and shrinkage are often major sources of dimensional error in finished parts. This phenomenon is explored along with various approaches for evaluating dimensional accuracy. Product design parameters, in particular, slice height, strongly impact surface roughness. A geometric model for surface roughness is also reviewed. Originality/value – This represents the first review of extrusion AM processes focusing on dimensional accuracy and surface roughness. Understanding and improving relationships between materials, design parameters and the ultimate properties of finished parts will be key to improving extrusion AM processes and expanding their applications.


Author(s):  
Kamaljit Singh Boparai ◽  
Gurpartap Singh ◽  
Rupinder Singh ◽  
Sarabjit Singh

Abstract In this work, 3D printed master patterns of acrylonitrile butadiene styrene (ABS) thermoplastic material have been used for the preparation of Ni-Cr based functional prototypes as partial dentures (PD). The study started with patient specific three dimensional (3D), CAD data (fetched through scanning). This data was used for preparation of .STL file for printing of master patterns on fused deposition modeling (FDM) setup. The 3D printed master patterns were further wax coated to reduce the surface irregularities (as cost effective post processing technique). The hybrid patterns were subjected to investment casting for the preparation of Ni-Cr based PD. The finally prepared functional prototypes as PD were optimized for dimensional accuracy, surface finish and surface hardness as responses. The results are visualized and supported by photomicrographs and in-vitro analysis.


2020 ◽  
pp. 009524432091683 ◽  
Author(s):  
Mojtaba Nabipour ◽  
Behnam Akhoundi

Recently, applications of three-dimensional (3-D) printers have extensively been increased in various industries. Fused deposition modeling process is one of the most widely used 3-D printing methods in this area due to its simplicity, reliability, and the ability to produce complex parts made of thermoplastic materials. In this research, composite sample parts consisted of copper particles with a constant 25 wt% of metallic powder as a filler and acrylonitrile butadiene styrene granules as a polymeric matrix. A filament production line to acquire printable filaments was applied and its optimum parameters were reported. Four printing parameters involved nozzle diameter, layer height, raster angle, and nozzle temperature were chosen in three levels for investigation of composite samples’ tensile strength, density, and production time as a new study. The Taguchi method, a well-known design of experiment tool, was employed to find the effect of each parameter and optimum levels with including the main effect, signal-to-noise ratio, and analysis of variance. Finally, optimum composite specimens manufactured by 3-D printer verified Taguchi method analysis and results.


2014 ◽  
Vol 20 (3) ◽  
pp. 215-220 ◽  
Author(s):  
Rupinder Singh ◽  
Gurwinder Singh

Purpose – The purpose of the present study is to investigate statistically controlled investment casting (IC) solution of fused deposition modeling (FDM)-based ABS replicas. Design/methodology/approach – The work started with the identification of the benchmark/component. Prototypes (to be used as pattern) were built on FDM with ABS plastic material, followed by IC. The measurements on final casting prepared were made on the co-ordinate measuring machine (CMM) from which international tolerance (IT) grades were calculated to establish the dimensional accuracy of the components. Findings – This study further highlighted the cast component properties (like hardness and surface finish) for suitability of this process. Final castings produced are acceptable as per international standard organization (ISO) standard UNI EN 20286-I (1995). Originality/value – This process ensures development of statistically controlled IC solution as technological prototypes and proof of concept at less production cost and time.


2014 ◽  
Vol 20 (3) ◽  
pp. 205-214 ◽  
Author(s):  
Wayne M. Johnson ◽  
Matthew Rowell ◽  
Bill Deason ◽  
Malik Eubanks

Purpose – The purpose of this paper is to present a qualitative and quantitative comparison and evaluation of an open-source fused deposition modeling (FDM) additive manufacturing (AM) system with a proprietary FDM AM system based on the fabrication of a custom benchmarking model. Design/methodology/approach – A custom benchmarking model was fabricated using the two AM systems and evaluated qualitatively and quantitatively. The fabricated models were visually inspected and scanned using a 3D laser scanning system to examine their dimensional accuracy and geometric dimensioning and tolerancing (GD&T) performance with respect to the computer-aided design (CAD) model geometry. Findings – The open-source FDM AM system (CupCake CNC) successfully fabricated most of the features on the benchmark, but the model did suffer from greater thermal warping and surface roughness, and limitations in the fabrication of overhang structures compared to the model fabricated by the proprietary AM system. Overall, the CupCake CNC provides a relatively accurate, low-cost alternative to more expensive proprietary FDM AM systems. Research limitations/implications – This work is limited in the sample size used for the evaluation. Practical implications – This work will provide the public and research AM communities with an improved understanding of the performance and capabilities of an open-source AM system. It may also lead to increased use of open-source systems as research testbeds for the continued improvement of current AM processes, and the development of new AM system designs and processes. Originality/value – This study is one of the first comparative evaluations of an open-source AM with a proprietary AM system.


2013 ◽  
Vol 13 (3) ◽  
pp. 183-197 ◽  
Author(s):  
Ranjeet Kumar Sahu ◽  
S.S. Mahapatra ◽  
Anoop Kumar Sood

AbstractFused Deposition Modeling (FDM) is an additive manufacturing technology for rapid prototyping that can build intricate parts in minimal time with least human intervention. The process parameters such as layer thickness, orientation, raster angle, raster width and air gap largely influence on dimensional accuracy of built parts which can be expressed as change in length, width and thickness. This paper presents experimental data and a fuzzy decision making logic in integration with the Taguchi method for improving the dimensional accuracy of FDM processed ABSP 400 parts. It is observed that length and width decreases but thickness shows positive deviation from desired value of the built part. Experimental results indicate that optimal factor settings for each response are different. Therefore, all the three responses are expressed in a single response index through fuzzy logic approach. The process parameters are optimized with consideration of all the performance characteristics simultaneously. Finally, an inference engine is developed to perform the inference operations on the rules for fuzzy prediction model based on Mamdani method. Experimental results are provided to confirm the effectiveness of the proposed approach. The predicted results are in good agreement with the values from the experimental data with average percentage error of less than 4.5.


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