Numerical simulation and printability analysis of fused deposition modeling with dual-temperature control

Ideal tissue engineering scaffolds need interconnected pores and high porosity to enable cell survival,migration,proliferation,and differentiation.However,obtaining a high-resolution structure is difficult with traditional one-temperature control fused deposition modeling(FDM).In this study,we propose a dual-temperature control method to improve printability.A numerical model is developed in which the viscosity is a function of temperature and shear rate to study the influence of two different temperature control modes.Quantitative tests are used to assess filament formation and shape fidelity,including one-dimensional filament printing,deposition at corners,fusion,and collapse.By using dual-temperature control,the width of the deposited poly(ε-caprolactone)filament is reduced to 50μm.The comparative results of both the experimental method and numerical simulation suggest that the dual-temperature control FDM can manufacture spatially arranged constructs and presents a promising application in tissue engineering。

Multi-Objective Optimization of Fused Deposition Modeling for Mechanical Properties of Biopolymer Parts Using the Grey-Taguchi Method

The urgent need to develop customized functional products only possible by 3D printing had realized when faced with the unavailability of medical devices like surgical instruments during the coronavirus-19 disease and the ondemand necessity to perform surgery during space missions.Biopolymers have recently been the most appropriate option for fabricating surgical instruments via 3D printing in terms of cheaper and faster processing.Among all 3D printing techniques,fused deposition modelling(FDM)is a low-cost and more rapid printing technique.This article proposes the fabrication of surgical instruments,namely,forceps and hemostat using the fused deposition modeling(FDM)process.Excellent mechanical properties are the only indicator to judge the quality of the functional parts.The mechanical properties of FDM-processed parts depend on various process parameters.These parameters are layer height,infill pattern,top/bottom pattern,number of top/bottom layers,infill density,flow,number of shells,printing temperature,build plate temperature,printing speed,and fan speed.Tensile strength and modulus of elasticity are chosen as evaluation indexes to ascertain the mechanical properties of polylactic acid(PLA)parts printed by FDM.The experiments have performed through Taguchi’s L27orthogonal array(OA).Variance analysis(ANOVA)ascertains the significance of the process parameters and their percent contributions to the evaluation indexes.Finally,as a multiobjective optimization technique,grey relational analysis(GRA)obtains an optimal set of FDM process parameters to fabricate the best parts with comprehensive mechanical properties.Scanning electron microscopy(SEM)examines the types of defects and strong bonding between rasters.The proposed research ensures the successful fabrication of functional surgical tools with substantial ultimate tensile strength(42.6 MPa)and modulus of elasticity(3274 MPa).

Effect of Fibre Size on Mechanical Properties and Surface Roughness of PLA Composites by Using Fused Deposition Modelling (FDM)

Naturalfibre as a reinforcing agent has been widely used in many industrial applications.Nevertheless,several factors need to be considered,such as the size and weight percentage of thefibre used in binding.Using fused deposition modelling(FDM),this factor was investigated by varying the size of naturalfibre as the responding variable with afixed weight percentage of kenaffibre.The process of modifying the naturalfibre in terms of size might increase the dispersion of kenaffibre in the polymer matrix and increase the adhesion bonding between thefibre and matrix of composites,subsequently improving the interfacial bonding between these two phases.In this paper,the effect offibre size was evaluated by performing the mechanical test,Scanning Electron Micrograph(SEM)to observe the morphology of the composites,and also by surface analysis.The surface roughness was visualised using a 3D profilometer and thefigure was illustrated as colour shading in the image.The composite withfibre size≤100μm displayed better tensile andflexural strength,compared to other sizes.In conclusion,by reducing the size of thefibre,the composites could develop high strength performance for industrial applications.

DECISION-MAKING OF SLICING SCHEME IN FUSED DEPOSITION MODELING PROCESS BASED ON ANALYTICAL HIERARCHICAL PROCESS

Based on analyzing the influences of a slicing scheme on stair-stepping effect, supporting structure, efficiency and deformation, etc. , analytical hierarchical process （AHP） combining with fuzzy synthetic evaluation is introduced to make decision in slicing schemes for a processing part. The application in determining the slicing scheme for a computer mouse during prototyping shows that the method increases the rationality during decision- making and improves quality and efficiency for the prototyping part.

基于机器学习耦合模型预测FDM零件的表面粗糙度

熔融沉积工艺(FDM)制造的零件表面粗糙度高,不仅影响了零件外观,还降低了性能。采用响应面实验设计,研究了层高(A)、填充密度(B)、喷嘴温度(C)、床层温度(D)和打印速度(E)对聚乳酸(PLA)零件表面粗糙度的影响。同时,将遗传算法(GA)与决策树(DT)、人工神经元网络(ANN)两种机器学习模型相结合,预测了零件的表面粗糙度。结果表明,A、B、C和E是显著影响零件表面粗糙度的主效应,A×B、A×C、A×E、B×C、B×E、C×E是影响显著的交互效应。GA+DT耦合模型预测PLA零件表面粗糙度的准确性更高,预测值与实验值的相关系数(R2)、均方误差(MSE)和平均绝对误差(MAE)分别为0.952、0.132和0.234,优于GA+ANN的0.823、1.561和1.759。GA+DT模型的预测值与实验值的Pearson相关系数为0.984,而GA+ANN模型仅为0.903,这表明GA+DT模型在预测PLA零件表面粗糙度时准确度更高。

FDM技术打印参数对成型效率的影响研究

FDM技术可用于工业领域中大型零件模型的打印,提升成型效率成为重要的研究课题。本研究通过响应面分析方法,探究了FDM打印参数对聚乳酸圆柱件成型效率的影响规律,得到了最优打印参数,并经过实际打印验证。结果表明层厚增加,成型效率提高;打印速度增加,成型效率提高;填充率增加,成型效率降低;路径规划和壁厚对成型效率影响不大。影响成型效率的因素按照顺序排列是:层厚>打印速度>填充率,其中层厚和打印速度影响显著。最优打印参数为打印速度85mm·s^(-1)、层厚0.175mm、填充率55%,预测时间为58.8min,实际时间为59min,预测精度达99.7%,为提升成型效率提供了依据。

Fabrication and Characterization of Poly Lactic Acid Scaffolds by Fused Deposition Modeling for Bone Tissue Engineering

Three-dimensional porous poly-lactic acid(PLA) scaffold was fabricated using fused deposition modeling(FDM) method including 30%, 50% and 70% nominal porosity. Study of phases in initial polymeric material and printed scaffolds was done by X-ray diffraction(XRD), and no significant phase difference was observed due to the manufacturing process, and the poly-lactic acid retains its crystalline properties. The results of the mechanical properties evaluation by the compression test show that the mechanical properties of the scaffold have decreased significantly with increasing the porosity of scaffold. The microstructure of scaffolds were studied by scanning electron microscope(SEM), showing that the pores had a regular arrangement and their morphology changed with porosity change. The mechanical properties of the poly-lactic acid scaffolds printed using fused deposition modeling, can be adapted to the surrounding tissue, by porosity change.

Optimization of Fused Deposition Modelling (FDM) Process Parameters Using Bacterial Foraging Technique

Fused deposition modelling (FDM) is a fast growing rapid prototyping (RP) technology due to its ability to build functional parts having complex geometrical shapes in reasonable build time. The dimensional accuracy, surface roughness, mechanical strength and above all functionality of built parts are dependent on many process variables and their settings. In this study, five important process parameters such as layer thickness, orientation, raster angle, raster width and air gap have been considered to study their effects on three responses viz., tensile, flexural and impact strength of test specimen. Experiments have been conducted using central composite design (CCD) and empirical models relating each response and process parameters have been developed. The models are validated using analysis of variance (ANOVA). Finally, bacterial foraging technique is used to suggest theoretical combination of parameter settings to achieve good strength simultaneously for all responses.

A fiber Bragg grating based earth and water pressures transducer with three-dimensional fused deposition modeling for soil mass

A novel fiber Bragg grating(FBG)sensor with three-dimensional(3D)fused deposition modeling(FDM)approach is proposed for effective stress measurement in soil mass.The three-diaphragm structure design is developed to measure earth and water pressures simultaneously.The proposed transducer has advantages of small size,high sensitivity,low cost,immunity to electromagnetic interference and rapid prototyping.The working principle,design parameters,and manufacturing details are discussed.The proposed transducer was calibrated for earth and water pressures measurement by using weights and a specially designed pressure chamber,respectively.The calibration results showed that the wavelength of the transducer was proportional to the applied pressure.The sensitivity coefficients of the earth and water pressures were 12.633 nm/MPa and 6.282 nm/MPa,respectively.Repeated tests and error analysis demonstrated the excellent stability and accuracy of the earth and water pressure measurements.The performance of the proposed transducer was further verified by a model experimental test and numerical analysis,which indicated that the proposed transducer has great potential for practical applications.

FDM用ABS复合材料的改性及其应用研究进展

丙烯腈-丁二烯-苯乙烯共聚物(ABS)具有良好的力学性能和可加工性。近年来,随着熔融沉积成型(FDM)三维(3D)打印技术的不断成熟和发展,ABS及其各类改性复合材料也相应被广泛应用于FDM。本文重点基于FDM技术,首先系统整理了金属类填料、无机非金属类填料、有机高分子类填料、回收废旧聚合物类填料等改性ABS基复合材料的现状,并对其相关性能进行了归纳。同时,对相应的各类ABS改性复合材料的FDM打印制品在医学、民用工业、军用电磁与吸波等领域的前沿应用进行了综述。最后,结合FDM打印技术和ABS改性现状,对未来FDM打印方法以及ABS改性技术提出了几点思考。

Tensile Properties of Mechanically-Defibrated Cellulose Nanofiber-Reinforced Polylactic Acid Matrix Composites Fabricated by Fused Deposition Modeling

Biodegradable polymers are highly attractive as potential alternatives to petroleum-based polymers in an attempt to achieve carbon neutrality whilst maintaining the mechanical properties of the structures.Among these polymers,polylactic acid(PLA)is particularly promising due to its good mechanical properties,biocompatibility and thermoplasticity.In this work,we aim to enhance the mechanical properties of PLA using mechanically-defibrated cellulose nanofibers(CNFs)that exhibit remarkable mechanical properties and biodegradability.We also employ fused deposition modeling(FDM),one of the three-dimensional printing methods for thermoplastic polymers,for the low-cost fabrication of the products.Mechanically-defibrated CNF-reinforced PLA matrix composites are fabricated by FDM.Their tensile properties are investigated in two printing directions(0°/90°and+45°/-45°).The discussion about the relationship between printing direction and tensile behavoir of mechanically-defibrated CNF-reinforced PLA matrix composite is the unique point of this study.We further discuss the microstructure and fracture surface of mechanically-defibrated CNF-reinforced PLA matrix composite by scanning electron microscope.

局部增强切片对3D打印FDM模型弯曲强度的影响

为了提高熔融沉积(FDM)3D打印模型的弯曲强度和比强度,通过Cura软件局部增强切片功能对聚乳酸(PLA)试样的中心区域进行了加强,使用FDM工艺制作了8组试样(包含0#参考组和1#~7#增强组),对各组试样进行三点弯曲实验,对比不同增强切片参数下PLA试样的弯曲强度和比强度。结果表明,随着局部增强填充密度的增大,PLA试样的弯曲强度先增大后减小;随着局部增强填充走线乘数的增大,PLA试样的弯曲强度逐渐增大;随着局部增强挤出倍率的增大,PLA试样的弯曲强度逐渐增大;与0#参考组相比,局部增强填充密度60%、局部增强填充走线乘数3、局部增强挤出倍率120%三种方式下PLA试样的比强度分别提高了16%,13%和5%,通过局部增强填充密度方式产生的比强度提升效果最好。因此,对于常规切片参数为填充密度20%、填充走线乘数1、挤出倍率100%的FDM模型,将局部增强区域填充密度设置为60%可以有效提高其弯曲强度和比强度。

PROTOTYPE SURFACE MICRO- PRECISION IN FUSED DEPOSITION MODELING PROCESS

To aim at prototype parts fabricated with fused deposition modeling （FDM） process, the problems how to improve and enhance their surface micro-precision are studied. The producing mechanism of surface roughness is explained with three aspects concretely including the principle error of rapid prototyping （RP） process, the inherent characteristics of FDM process, and some mi- cro-scratches on the surface of the extruded fiber. Based on the micro-characters of section shape of the FDM prototype, a physical model reflecting the outer shape characters is abstracted. With the physical simplified and deduced, the evaluating equations of surface roughness are acquired. According to the FDM sample parts with special design for experimental measurement, the real surface roughness values of different inclined planes are obtained. And the measuring values of surface roughness are compared with the calculation values. Furthermore, the causes of surface roughness deviation between measuring values and calculation values are respectively analyzed and studied. With the references of analytic conclusions, the measuring values of the experimental part surface are revised, and the revised values nearly accord with the calculation values. Based on the influencing principles of FDM process parameters and special post processing of FDM prototype parts, some concrete measures are proposed to reduce the surface roughness of FDM parts, and the applying effects are better.

Minimizing Warpage for Macro-Size Fused Deposition Modeling Parts

In this study,we investigated warpage and corner lifting minimization for three-dimensional printed parts generated by macro-size fused deposition modeling(FDM).First,the reasons for warpage were theoretically elucidated.This approach revealed that the thermal deformation and differential volumetric shrinkage of the extruded molten plastic resulted in warpage of FDM parts.In addition,low adhesion between the deposited model and the heated or non-heated printing bed may intensify warpage further.As a next step,initial small-size and medium-size models were used to identify parameters to manage and minimize warpage in a way that would reduce material consumption and running time.Finally,a macro-size model was built to experimentally investigate and verify the technical solutions to minimize the warpage of FDM parts.In conclusion,an improved part with reduced warpage was efficiently produced after detailed consideration of thermal effects and adhesion force.Potential exists to widen the application scope of FDM technology in manufacturing for processes like thermoforming that involve mold core fabrication with heating.This technology,which has applications not only in mechanical engineering but also in related engineering fields,is convenient and could readily be applied to practical manufacturing industries.

基于FDM的PEEK/CGF复合材料综合力学性能优化

为提升连续玻璃纤维增强聚醚醚酮(PEEK/CGF)复合材料熔融沉积成型(FDM)制品的力学性能,通过单因素试验,Plackett-Burman Design试验与Box-Behnken Design试验,研究了保温舱温度、常用打印路径(5种)、层厚、道间距等工艺参数对PEEK/CGF复合材料样件综合力学性能的影响规律,寻求最优工艺参数组合并进行试验验证。结果表明,各工艺参数对力学性能影响程度大小排序为打印路径>道间距>保温舱温度>层厚;各工艺参数之间存在相互作用,适当的工艺参数组合可以使力学性能得到大幅提升,其中相较于拉伸强度,弯曲强度受工艺参数间的相互作用更为明显;当保温舱温度为82℃、层厚为1.0 mm、打印路径为0°/0°/0°/0°、道间距为0.7 mm时,拉伸强度可得最大值为383.75 MPa,当保温舱温度为73℃、层厚为0.75 mm、打印路径为0°/0°/0°/0°、道间距为1.0 mm时,弯曲强度可得最大值510.13 MPa。

3D Printing with a 5-Axis FDM Printer Using Bézier Techniques

In the last decade,3D printing,especially fused deposition modeling(FDM),has revolutionized manufacturing with intricate designs.Traditional 3-axis FDM printers face challenges with complex geometries,but 5-axis versions offer more design freedom.However,it requires specialized strategies.This research presents a model for 5-axis FDM printers using Bézier curves with an algorithm to enhance print quality.The result shows significant accuracy improvements,especially for curve-based tasks.In addition,this study deepens the understanding of 5-axis FDM technology,setting a solid basis for further research and potentially refining manufacturing methods.

层厚和模型底角对FDM表面成型质量的影响研究

轮廓表面粗糙度是影响熔融沉积成型(FDM)模型质量的关键因素,为了揭示层厚和模型底角对粗糙度的影响机理和规律,对FDM成型机理、软件切片算法、硬件实际工况进行分析,并构建了数学模型来研究垂直直线型轮廓和倾斜直线型轮廓。根据FDM成型机理,建立数学表达式,采用MATLAB软件进行运算分析,研究了层厚和模型底角两个参数对成型件表面粗糙度的影响规律。为了验证数学模型的有效性,设计二因素三水平正交试验,通过超景深显微镜观察发现,在层厚取最小值,模型底角取最大值时,成型件表面质量最佳。这与仿真结果一致。研究结论为提高表面粗糙度指明了方向,同时也为实际成型件的工艺参数优化提供了理论依据。

Properties of ABS/Organic-Attapulgite Nanocomposites Parts Fabricated by Fused Deposition Modeling

The paper discusses the mechanical and thermal performance manifested in natural nanorods attapulgite(ATP)reinforced Acrylonitrile butadiene styrene(ABS)nanocomposites in the process of fused deposition modeling(FDM).Molten extrusion technique was taken to manufacture the filaments of ABS/organic-attapulgite(OAT)nanocomposites with different mass fraction and the printing operation was made by one commercial FDM three-dimensional(3D)printer.Results indicate that the mechanical performance of these FDM 3D printed specimens are improved obviously via the introduction of OAT,and tensile strength of the ABS/OAT nanocomposites parts with only 2 wt%OAT addition is enhanced by 48.1%.At the same time,the addition OAT can reduce the linear expansion coefficient and creep flexibility,and improve the thermal stability and dimensional accuracy of these FDM 3D printed parts.

Concurrent Material Selection of Natural Fibre Filament for Fused Deposition Modeling Using Integration of Analytic Hierarchy Process/Analytic Network Process

The employment of natural fibres in fused deposition modeling has raised much attention from researchers in finding a suitable formulation for the natural fibre composite filaments.Moreover,selection of suitable natural fibres for fused deposition modeling should be performed before the development of the composites.It could not be performed without identifying selection criteria that comprehend both materials and fused deposition modeling process requirements.Therefore,in this study,integration of the Analytic Hierarchy Process(AHP)/Analytic Network Process(ANP)has been introduced in selecting the natural fibres based in different clusters of selection concurrently.The selection process has been performed based on the interdependency among the selection criteria.Pairwise comparison matrices are constructed based on AHP’s hierarchical model and super matrices are constructed based on the ANP’s network model.As a result,flax fibre has ranked at the top of the selection by scored 19.5%from the overall evaluation.Flax fibre has excellent material properties and been found in various natural fibre composite applications.Further investigation is needed to study the compatibility of this fibre to be reinforced with a thermoplastic polymer matrix to develop a resultant natural fibre composite filament for fused deposition modeling.

基于遗传算法-模糊PID的双喷头FDM型3D打印机温度控制方法

熔融沉积成形(fused deposition modeling,FDM)3D打印需要将打印喷头加热至材料所需温度后才能开始打印。由于单喷头FDM型3D打印机的打印效率较低,以及其加热系统的滞后性较大且稳定性差,使得整个成形过程既耗时又浪费资源,且成形件的质量不高。为解决上述问题,结合打印材料物理性质和化学性质的差异性,提出了一种基于遗传算法-模糊PID(proportional-integral-derivative,比例-积分-微分)的温度控制方法,以实现对双喷头FDM型3D打印机加热方法的控制,并建立温度控制系统的MATLAB/Simulink仿真模型,以验证所提出的控制方法的可靠性。仿真和实验结果表明,与传统PID控制、模糊PID控制相比,遗传算法-模糊PID控制的响应时间缩短了36.03%和32.45%,调节时间缩短了28.06%和20.99%,具有响应速度快、调节时间短、超调量小和控制效果稳定等优势。研究结果可为复合材料的双喷头FDM 3D打印提供参考。