scholarly journals Laser-based additively manufactured polymers: a review on processes and mechanical models

2020 ◽  
Vol 56 (2) ◽  
pp. 961-998
Author(s):  
Roberto Brighenti ◽  
Mattia Pancrazio Cosma ◽  
Liviu Marsavina ◽  
Andrea Spagnoli ◽  
Michele Terzano
Keyword(s):  
Process Parameters ◽  
Mechanical Performance ◽  
Selective Laser Sintering ◽  
Theoretical Models ◽  
Raw Material ◽  
Laser Source ◽  
Mechanical Resistance ◽  
Layer By Layer ◽  
Influence Of Process Parameters ◽  
Mechanical Models

Abstract Additive manufacturing (AM) is a broad definition of various techniques to produce layer-by-layer objects made of different materials. In this paper, a comprehensive review of laser-based technologies for polymers, including powder bed fusion processes [e.g. selective laser sintering (SLS)] and vat photopolymerisation [e.g. stereolithography (SLA)], is presented, where both the techniques employ a laser source to either melt or cure a raw polymeric material. The aim of the review is twofold: (1) to present the principal theoretical models adopted in the literature to simulate the complex physical phenomena involved in the transformation of the raw material into AM objects and (2) to discuss the influence of process parameters on the physical final properties of the printed objects and in turn on their mechanical performance. The models being presented simulate: the thermal problem along with the thermally activated bonding through sintering of the polymeric powder in SLS; the binding induced by the curing mechanisms of light-induced polymerisation of the liquid material in SLA. Key physical variables in AM objects, such as porosity and degree of cure in SLS and SLA respectively, are discussed in relation to the manufacturing process parameters, as well as to the mechanical resistance and deformability of the objects themselves. Graphic abstract

scholarly journals Fused Deposition Modelling of Fibre Reinforced Polymer Composites: A Parametric Review

2021 ◽  
Vol 5 (1) ◽  
pp. 29
Author(s):  
Narongkorn Krajangsawasdi ◽  
Lourens G. Blok ◽  
Ian Hamerton ◽  
Marco L. Longana ◽  
Benjamin K. S. Woods ◽  
...  
Keyword(s):  
Process Parameters ◽  
Mechanical Performance ◽  
Fibre Length ◽  
Processing Parameters ◽  
Thermoplastic Composite ◽  
Fused Deposition Modelling ◽  
Layer By Layer ◽  
Fused Deposition ◽  
Fibre Reinforced Polymer ◽  
Printing Parameters

Fused deposition modelling (FDM) is a widely used additive layer manufacturing process that deposits thermoplastic material layer-by-layer to produce complex geometries within a short time. Increasingly, fibres are being used to reinforce thermoplastic filaments to improve mechanical performance. This paper reviews the available literature on fibre reinforced FDM to investigate how the mechanical, physical, and thermal properties of 3D-printed fibre reinforced thermoplastic composite materials are affected by printing parameters (e.g., printing speed, temperature, building principle, etc.) and constitutive materials properties, i.e., polymeric matrices, reinforcements, and additional materials. In particular, the reinforcement fibres are categorized in this review considering the different available types (e.g., carbon, glass, aramid, and natural), and obtainable architectures divided accordingly to the fibre length (nano, short, and continuous). The review attempts to distil the optimum processing parameters that could be deduced from across different studies by presenting graphically the relationship between process parameters and properties. This publication benefits the material developer who is investigating the process parameters to optimize the printing parameters of novel materials or looking for a good constituent combination to produce composite FDM filaments, thus helping to reduce material wastage and experimental time.

Research on Warpage of Polystyrene in Selective Laser Sintering

2010 ◽  
Vol 43 ◽  
pp. 578-582 ◽  
Author(s):  
C.Y. Wang ◽  
Q. Dong ◽  
X.X. Shen
Keyword(s):  
Layer Thickness ◽  
Process Parameters ◽  
Laser Power ◽  
Selective Laser Sintering ◽  
Scanning Speed ◽  
Laser Sintering ◽  
Main Process ◽  
Influence Of Process Parameters ◽  
Temperature Changes ◽  
Hatch Spacing

Warpage is a crucial factor to accuracy of sintering part in selective laser sintering (SLS) process. In this paper, The influence of process parameters on warpage when sintering polystyrene(PS) materials in SLS are investigated. The laser power, scanning speed, hatch spacing, layer thickness as well as temperature of powder are considered as the main process parameters. The results showed that warpage increases with the increase of hatch space. Contary to it, warpage decreases with the increase of laser power. Warpage decreases with the increase of layer thickness between 0.16~0.18mm and changes little with increase of the thickness. Warpage increases along with the increase of scanning speed but decreases when the speed is over about 2000mm/s. When the temperature changes between 82°C-86°C, warpage decreases little with the increase of temperature. But further increase of temperature leads to warpage decreasing sharply when the temperature changes between 86°C-90°C.

Influence of Process Parameters and Raw Material on the Characteristics of Hydrolyzed Feather Meal

2020 ◽  
Author(s):  
Marcia Regina Sinhorini ◽  
Evellin Balbinot-Alfaro ◽  
Wagner de Aguiar ◽  
Alexandre da Trindade Alfaro
Keyword(s):  
Process Parameters ◽  
Raw Material ◽  
Feather Meal ◽  
Influence Of Process Parameters

Experimental Study on Warping Height of PA12/HDPE Specimen by Selective Laser Sintering

2010 ◽  
Vol 43 ◽  
pp. 430-433
Author(s):  
Nai Fei Ren ◽  
Pan Wang ◽  
Yan Luo ◽  
Hui Juan Wu
Keyword(s):  
Process Parameters ◽  
Selective Laser Sintering ◽  
Single Layer ◽  
Dimensional Accuracy ◽  
Laser Sintering ◽  
Sintering Process ◽  
Influence Of Process Parameters ◽  
Optimum Parameters ◽  
Scan Speed ◽  
The Relationship

The dimensional accuracy and mechanics properties of parts made by Selective Laser Sintering depend greatly on the sintering process parameters. The influence of process parameters on warping weight of parts sintered by blends of polyamide (PA12) and high density polyethylene (HDPE) was studied. The relationship between the process parameters and the warping height was presented. The surface morphology of the part and uniformity of powder mixed were analyzed by SEM. The optimum parameters of minimum warping height were obtained: preheat temperature 110°C, scan speed 300mm/s, laser power 21W, thickness of single layer 0.2mm.

scholarly journals The Influence of Process Parameters and Build Orientation on the Creep Behaviour of a Laser Powder Bed Fused Ni-based Superalloy for Aerospace Applications

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1390 ◽  
Author(s):  
Hani Hilal ◽  
Robert Lancaster ◽  
Spencer Jeffs ◽  
John Boswell ◽  
David Stapleton ◽  
...  
Keyword(s):  
Process Parameters ◽  
Structural Integrity ◽  
Mechanical Performance ◽  
Creep Behaviour ◽  
Test Method ◽  
Influence Of Process Parameters ◽  
Powder Bed ◽  
Build Orientation ◽  
Aerospace Applications ◽  
Layer Manufacturing

Additive Layer Manufacturing (ALM) is an innovative net shape manufacturing technology that offers the ability to produce highly intricate components not possible through traditional wrought and cast procedures. Consequently, the aerospace industry is becoming ever more attentive in exploiting such technology for the fabrication of nickel-based superalloys in an attempt to drive further advancements within the holistic gas turbine. Given this, the requirement for the mechanical characterisation of such material is rising in parallel, with limitations in the availability of material processed restricting conventional mechanical testing; particularly with the abundance of process parameters to evaluate. As such, the Small Punch Creep (SPC) test method has been deemed an effective tool to rank the elevated temperature performance of alloys processed through ALM, credited to the small volumes of material utilised in each test and the ability to sample material from discrete locations. In this research, the SPC test will be used to assess the influence of a number of key process variables on the mechanical performance of Laser Powder Bed Fused (LPBF) Ni-based superalloy CM247LC. This will also include an investigation into the influence of build orientation and post-build treatment on creep performance, whilst considering the structural integrity of the different experimental builds.

scholarly journals Numerical Model and Experimental Validation for Laser Sinterable Semi-Crystalline Polymer: Shrinkage and Warping

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1373 ◽  
Author(s):  
Jiang Li ◽  
Shangqin Yuan ◽  
Jihong Zhu ◽  
Shaoying Li ◽  
Weihong Zhang
Keyword(s):  
Heat Transfer ◽  
Selective Laser Sintering ◽  
Dimensional Accuracy ◽  
Polymeric Materials ◽  
Crystalline Polymer ◽  
Raw Material ◽  
Critical Issues ◽  
Mechanical Models ◽  
Powder Fusion ◽  
Polymer Shrinkage

Shrinkage and warping of additive manufacturing (AM) parts are two critical issues that adversely influence the dimensional accuracy especially in powder bed fusion processes such as selective laser sintering (SLS). Powder fusion, material solidification, and recrystallization are the key stages causing volumetric changes of polymeric materials during the abrupt heating–cooling process. In this work, the mechanisms of shrinkage and warping of semi-crystalline polyamide (PA) 12 in SLS are well investigated. Heat-transfer and thermo-mechanical models are established to predict the process-dependent shrinkage and warping. The influence of raw material- and laser-related parameters are considered in the heat-transfer and thermo-mechanical models. Such models are established considering the natural thermal gradient and dynamic recrystallization, which induce internal strain and volumetric change. Moreover, an experimental design via orthogonal approach is introduced to validate the feasibility and accuracy of the proposed models. Finally, the quantitative relationships of process parameters with product shrinkage and warping are established; the dimensional accuracy in part-scale can be well predicted and validated with printed parts in a real experiment.

Additive Manufacturing of Continuous Carbon Fiber Reinforced Thermoplastic Composites: An Investigation on Process-Impregnation-Property Relationship

2020 ◽  
Author(s):  
Gongshuo Wang ◽  
Zhenyuan Jia ◽  
Fuji Wang ◽  
Chuanhe Dong ◽  
Bo Wu
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Carbon Fiber ◽  
Process Parameters ◽  
Mechanical Performance ◽  
Movement Speed ◽  
Fiber Reinforced ◽  
Influence Of Process Parameters ◽  
Continuous Carbon Fiber ◽  
Carbon Fiber Reinforced

Abstract Fused filament fabrication (FFF) is one of the most broadly used additive manufacturing technologies, which possesses the advantage of a reduction in fabrication time and cost for complex-structural parts. FFF-fabricated continuous carbon fiber reinforced thermoplastic (C-CFRTP) composites have seen their great potentials in the industry due to the extraordinary mechanical properties. However, the relationship among process parameters, impregnation percentage, and mechanical properties is still unknown, which has greatly hindered both the manufacturing and application of those advanced composite parts. For this reason, the influence of process parameters on the impregnation percentage and mechanical properties of C-CFRTP specimens has been investigated in this paper. The process-impregnation-properties relationship of FFF-fabricated C-CFRTP specimens has been revealed through theoretical analyses and experimental measurement. It could be concluded that the impregnation percentage served as the bridge connecting process parameters and mechanical properties, which would provide a great insight into the property improvement. The experimental results of microscopic measurement and mechanical tests indicated that the combination of low transverse movement speed, high nozzle temperature, and small layer thickness led to an improved impregnation percentage, which ultimately produced better mechanical properties. The findings in this work will guide the fabrication of C-CFRTP parts with excellent mechanical performance for practical engineering applications.

Sign in / Sign up

Export Citation Format

Share Document