scholarly journals A new algorithm for build time estimation for fused filament fabrication technologies

Author(s):  
Zicheng Zhu ◽  
Vimal Dhokia ◽  
Stephen T Newman

The manufacture of highly complex and accurate part geometries with reduced costs has led to the emergence of hybrid manufacturing technologies where varied manufacturing operations are carried out in either parallel or serial manner. One such hybrid process being currently developed is the iAtractive process, which combines additive (i.e. fused filament fabrication, which is sometimes called fused deposition modelling. However, the latter term is trademarked by Stratasys Inc. and cannot be used publicly without authorisation from Stratasys) and subtractive (i.e. computer numerical control machining) processes. In the iAtractive process production, operation sequencing of additive and subtractive operations is essential. This requires accurate estimation of production time, in which the fused filament fabrication build time is the determining factor. There have been some estimators developed for fused deposition modelling. However, these estimators are not applicable to hybrid manufacturing, particularly in process planning, which is a vital stage. This article addresses the characteristics of fused filament fabrication technologies and develops a novel and rigorous method for predicting build times. An analytical model was first created to theoretically analyse the factors that affect the part build time and was subsequently used to facilitate the design of test parts and experiments. The experimental results indicate that part volume, interaction of volume and porosity and interaction of height and intermittent factor have significant effects on build times. Finally, the estimation algorithm has been developed, which was subsequently evaluated and validated by applying a wide range of identified influential factors. The major advantage of the new proposed algorithm is its ability to estimate the build time based on simple geometrical parameters of a given part. The key factors that drive the algorithm can be directly obtained from part dimensions/drawings, providing an efficient and accurate way for fused filament fabrication time estimation. Test part evaluations and analysis have clearly demonstrated that estimation errors range from 0.1% to 13.5%, showing the validity, capability and significance of the developed algorithm and its applications to hybrid manufacture.

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3982 ◽  
Author(s):  
Gustavo Medina-Sanchez ◽  
Rubén Dorado-Vicente ◽  
Eloísa Torres-Jiménez ◽  
Rafael López-García

Build time is a key issue in additive manufacturing, but even nowadays, its accurate estimation is challenging. This work proposes a build time estimation method for fused filament fabrication (FFF) based on an average printing speed model. It captures the printer kinematics by fitting printing speed measurements for different interpolation segment lengths and changes of direction along the printing path. Unlike analytical approaches, printer users do not need to know the printer kinematics parameters such as maximum speed and acceleration or how the printer movement is programmed to obtain an accurate estimation. To build the proposed model, few measurements are needed. Two approaches are proposed: a fitting procedure via linear and power approximations, and a Coons patch. The procedure was applied to three desktop FFF printers, and different infill patterns and part shapes were tested. The proposed method provides a robust and accurate estimation with a maximum relative error below 8.5%.


TEM Journal ◽  
2020 ◽  
pp. 966-970
Author(s):  
Damir Hodžić ◽  
Adi Pandžić ◽  
Ismar Hajro ◽  
Petar Tasić

Widely used additive manufacturing technique for plastic materials is Fused Deposition Modelling (FDM). The FDM technology has gained interest in industry for a wide range of applications, especially today when large number of different materials on the market are available. There are many different manufacturers for the same FDM material where the difference in price goes up to 50%. This experimental study investigates possible difference in strength of the 3D printed PLA material of five different manufacturers. All specimens are 3D printed on Ultimaker S5 printer with the same printing parameters, and they are all the same colour.


Author(s):  
Martin Hallmann ◽  
Benjamin Schleich ◽  
Sandro Wartzack

AbstractWhen using additive manufacturing processes, the choice of the numerous settings for the process and design parameters significantly influences the build and production time. To reduce the required build time, it is useful to adapt the parameters with the greatest influence. However, since the contribution of the individual parameters is not readily apparent, a sensible choice of process and design parameters can become a challenging task.Thus, the following article presents a method, that enables the product developer to determine the main contributors to the required build time of additively manufactured products. By using this sensitivity analysis method, the contributors of the individual parameters can be analyzed for a given parametrized CAD model with the help of an analysis-based build time estimation approach. The novelty of the contribution can be found in providing a method that allows studying both design and process parameters simultaneously, taking the machine to be used into account. The exemplary application of the presented method to a sample part manufactured by Fused Deposition Modeling demonstrates its benefits and applicability.


Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 457 ◽  
Author(s):  
Philipp Sauerbier ◽  
James Anderson ◽  
Douglas Gardner

Recent advances in large-scale thermoplastic additive manufacturing (AM), using fused deposition modelling (FDM), have shown that the technology can effectively produce large aerospace tools with common feed stocks, costing 2.3 $/kg, such as a 20% carbon-filled acrylonitrile butadiene styrene (ABS). Large-scale additive manufacturing machines have build-volumes in the range of cubic meters and use commercially available pellet feedstock thermoplastics, which are significantly cheaper (5–10 $/kg) than the filament feedstocks for desktop 3D printers (20–50 $/kg). Additionally, large-scale AM machines have a higher material throughput on the order of 50 kg/h. This enables the cost-efficient tool production for several industries. Large-scale 3D-printed tooling will be computerized numerical control (CNC)-machined and -coated, to provide a surface suitable for demolding the composite parts. This paper outlines research undertaken to review and improve the adhesion of the coating systems to large, low-cost AM composite tooling, for marine or infrastructure composite applications. Lower cost tooling systems typically have a lower dimensional accuracy and thermal operating requirements than might be required for aerospace tooling. As such, they can use lower cost commodity grade thermoplastics. The polymer systems explored in the study included polypropylene (PP), styrene-maleic anhydride (SMA), and polylactic acid (PLA). Bio-based filler materials were used to reduce cost and increase the strength and stiffness of the material. Fillers used in the study included wood flour, at 30% by weight and spray-dried cellulose nano-fibrils, at 20% by weight. Applicable adhesion of the coating was achieved with PP, after surface treatment, and untreated SMA and PLA showed desirable coating adhesion results. PLA wood-filled composites offered the best properties for the desired application and, furthermore, they have environment-friendly advantages.


Author(s):  
S H Ahn ◽  
S McMains ◽  
C H Séquin ◽  
P K Wright

Inspired by the metal oxide system implementation service (MOSIS) project, CyberCut is an experimental fabrication testbed for an Internet-accessible, computerized prototyping and machining service. Client-designers can create mechanical components, generally using our web-based computer aided design (CAD) system (available at http://cad.berkeley.edu ), and submit appropriate files to the server at Berkeley for process planning. CyberCut then utilizes an open-architecture, computer numerical control (CNC) machine tool for fabrication. Rapid tool path planning, novel fixturing techniques and sensor-based precision machining techniques allow the designer to take delivery of a component machined from high-strength materials with good tolerances, e.g. ±0.002in (0.05 mm). There are also instances where the complex geometry of a component cannot be prototyped on our three-axis machine tool. For these components use is made of solid freeform fabrication (SFF) technologies such as fused deposition modelling (FDM) to build a prototype of the design. Based on experience with this testbed, a new characterization of types of relationship, or ‘couplings’, between design and manufacturing has been developed using the three classifications ‘loose and repetitive’, ‘stiff and one-way’ or ‘strong and bidirectional’. These three couplings represent different trade-offs between ‘design flexibility’ and ‘guaranteed manufacturability’.


Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3555
Author(s):  
Patrich Ferretti ◽  
Gian Maria Santi ◽  
Christian Leon-Cardenas ◽  
Elena Fusari ◽  
Giampiero Donnici ◽  
...  

Additive manufacturing processes have evolved considerably in the past years, growing into a wide range of products through the use of different materials depending on its application sectors. Nevertheless, the fused deposition modelling (FDM) technique has proven to be an economically feasible process turning additive manufacture technologies from consumer production into a mainstream manufacturing technique. Current advances in the finite element method (FEM) and the computer-aided engineering (CAE) technology are unable to study three-dimensional (3D) printed models, since the final result is highly dependent on processing and environment parameters. Because of that, an in-depth understanding of the printed geometrical mesostructure is needed to extend FEM applications. This study aims to generate a homogeneous structural element that accurately represents the behavior of FDM-processed materials, by means of a representative volume element (RVE). The homogenization summarizes the main mechanical characteristics of the actual 3D printed structure, opening new analysis and optimization procedures. Moreover, the linear RVE results can be used to further analyze the in-deep behavior of the FDM unit cell. Therefore, industries could perform a feasible engineering analysis of the final printed elements, allowing the FDM technology to become a mainstream, low-cost manufacturing process in the near future.


Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2608 ◽  
Author(s):  
Mohammadreza Lalegani Dezaki ◽  
Mohd Khairol Anuar Mohd Ariffin ◽  
Mohd Idris Shah Ismail

Fused deposition modelling (FDM) opens new ways across the industries and helps to produce complex products, yielding a prototype or finished product. However, it should be noted that the final products need high surface quality due to their better mechanical properties. The main purpose of this research was to determine the influence of computer numerical control (CNC) machining on the surface quality and identify the average surface roughness (Ra) and average peak to valley height (Rz) when the specimens were printed and machined in various build orientations. In this study, the study samples were printed and machined to investigate the effects of machining on FDM products and generate a surface comparison between the two processes. In particular, the block and complex specimens were printed in different build orientations, whereby other parameters were kept constant to understand the effects of orientation on surface smoothness. As a result, wide-ranging values of Ra and Rz were found in both processes for each profile due to their different features. The Ra values for the block samples, printed samples, and machined samples were 21, 91, and 52, respectively, whereas the Rz values were identical to Ra values in all samples. These results indicated that the horizontal surface roughness yielded the best quality compared to the perpendicular and vertical specimens. Moreover, machining was found to show a great influence on thermoplastics in which the surfaces became smooth in the machined samples. In brief, this research showed that build orientation had a great effect on the surface texture for both processes.


Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 941 ◽  
Author(s):  
A.P. Valerga ◽  
S.R. Fernandez-Vidal ◽  
F. Girot ◽  
A.J. Gamez

Nowadays, improvement of the surface finish of parts manufactured by fused deposition modelling is a well-studied topic. Chemical post-treatments have proven to be the best technique in terms of time consumption and smoothness improvement. However, these treatments modify the structure of the material and, consequently, its mechanical properties. This relationship was studied in this work. In this case, on the basis of a previous study on crystallisation, polylactic acid pieces were subjected to different post-treatments to evaluate their effects on the sample’s mechanical properties, i.e., tensile strength and hardness. Models were obtained according to their percentage of crystallisation, which was related to the different treatments, as well as immersion time. Dramatic changes were obtained within a wide range of material behaviour with some treatments. Specifically, changes were obtained in the maximum stress (from 55 to 20 MPa), in elongation (from 3% to 260%), and in the hardness scale (Shore D to A).


Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1220 ◽  
Author(s):  
Sofiane Guessasma ◽  
Sofiane Belhabib ◽  
Hedi Nouri

Polyethylene terephthalate glycol (PETG) is a thermoplastic formed by polyethylene terephthalate (PET) and ethylene glycol and known for his high impact resistance and ductility. The printability of PETG for fused deposition modelling (FDM) is studied by monitoring the filament temperature using an infra-red camera. The microstructural arrangement of 3D printed PETG is analysed by means of X-ray micro-tomography and tensile performance is investigated in a wide range of printing temperatures from 210 °C to 255 °C. A finite element model is implemented based on 3D microstructure of the printed material to reveal the deformation mechanisms and the role of the microstructural defects on the mechanical performance. The results show that PETG can be printed within a limited range of printing temperatures. The results suggest a significant loss of the mechanical performance due to the FDM processing and particularly a substantial reduction of the elongation at break is observed. The loss of this property is explained by the inhomogeneous deformation of the PETG filament. X-ray micro-tomography results reveal a limited amount of process-induced porosity, which only extends through the sample thickness. The FE predictions point out the combination of local shearing and inhomogeneous stretching that are correlated to the filament arrangement within the plane of construction.


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