Modeling and prediction of surface roughness and dimensional accuracy in SLS 3D printing of PVA/CB composite using the central composite design

Purpose: To compare the dimensions accuracy and surface roughness of polymeric dental bridges produced by different 3D printers. Design/methodology/approach: Four-part dental bridges were manufactured by three printing systems working on the basis of digital light projection (DLP) stereolithography (SLA), laser-assisted SLA and fused deposition modeling (FDM). The materials used from SLA printers are liquid methacrylate photopolymer resins, while FDM printer use thin wire plastic polylactic acid. The accuracy of the external dimensions of dental bridges was evaluated and the surface roughness was measured. Findings: It was found that compared to the base model, the dimensions of the SLA printed bridges are bigger with 1.25%-6.21%, while the corresponding dimensions of the samples, made by FDM are smaller by 1.07%-4.71%, regardless the position of the object towards the substrate. The samples, produced by FDM, are characterized with the highest roughness. The average roughness deviation (Ra) values for DLP SLA and lase-assisted SLA are 2.40 μm and 2.97 μm, respectively. Research limitations/implications: For production of high quality polymeric dental constructions next research should be targeted to investigation of the polymerization degree, stresses and deformations. Practical implications: Our study shows that 3D printers, based on laser-assisted and DLP SLA, can be successfully used for manufacturing of polymeric dental bridges – temporary restorations or cast patterns, while FDM system is more suitable for training models. The results will help the dentists to make right choice of the most suitable 3D printer. Originality/value: One of the largest fixed partial dentures – four-part bridges, produced by three different commercial 3D printing systems, were investigated by comparative analysis. The paper will attract readers’ interest in the field of biomedical materials and application of new technologies in dentistry.

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Effects of Process Parameters on Surface Roughness, Dimensional Accuracy and Printing Time in 3D Printing

Lecture Notes in Mechanical Engineering - Advances in Production and Industrial Engineering ◽

10.1007/978-981-15-5519-0_15 ◽

2020 ◽

pp. 187-197

Author(s):

Rajat Jain ◽

Shivansh Nauriyal ◽

Vishal Gupta ◽

Kanwaljit Singh Khas

Keyword(s):

Surface Roughness ◽

3D Printing ◽

Process Parameters ◽

Dimensional Accuracy ◽

Printing Time

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Central Composite Design Optimisation in Single Point Incremental Forming of Truncated Cones from Commercially Pure Titanium Grade 2 Sheet Metals

Materials ◽

10.3390/ma14133634 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3634

Author(s):

Marcin Szpunar ◽

Robert Ostrowski ◽

Tomasz Trzepieciński ◽

Ľuboš Kaščák

Keyword(s):

Surface Roughness ◽

Central Composite Design ◽

Feed Rate ◽

Incremental Forming ◽

Single Point ◽

Pure Titanium ◽

Single Point Incremental Forming ◽

Forming Force ◽

Step Size ◽

Central Composite

Single point incremental forming (SPIF) is an emerging process that is well-known to be suited for fabrication in small series production. The aim of this paper was to determine the optimal input parameters of the process in order to minimise the maximum of both the axial and the in-plane components of the forming force achieved during SPIF and the surface roughness of the internal surface of truncated-cone drawpieces. Grade 2 pure titanium sheets with a thickness of 0.4 mm were used as the test material. The central composite design and response surface method was used to determine the number of experiments required to study the responses through building a second-order quadratic model. Two directions of rotation of the forming tool were also considered. The input parameters were spindle speed, tool feed rate, and step size. The mathematical relations were defined using the response surfaces to predict the surface roughness of the drawpieces and the components of the forming force. It was found that feed rate has an insignificant role in both axial and in-plane forming forces, but step size is a major factor affecting axial and radial forming forces. However, step size directly affects the surface roughness on the inner surfaces of the drawpieces. Overall, the spindle speed −579 rpm (clockwise direction), tool feed 2000 mm/min, and step size 0.5 mm assure a minimisation of both force components and the surface roughness of drawpieces.

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A Study on Coolant Parameters in Internal Grinding of 9CrSi Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.950.24 ◽

2019 ◽

Vol 950 ◽

pp. 24-31 ◽

Cited By ~ 7

Author(s):

Le Xuan Hung ◽

Vu Thi Lien ◽

Vu Ngoc Pi ◽

Banh Tien Long

Keyword(s):

Surface Roughness ◽

Regression Model ◽

Central Composite Design ◽

Flow Rate ◽

Optimal Parameters ◽

Machining Processes ◽

Internal Grinding ◽

Surface Method ◽

Internal Cylindrical Grinding ◽

Central Composite

This paper aims to analysis the effect of coolant parameters on surface roughness in internal cylindrical grinding of annealed 9CrSi steel. The concentration and flow rate of the coolant are investigated in thirteen experiments by central composite design and response surface method. The effect of each parameter and their interaction on the surface roughness are analyzed by their regression model. From that model, optimal parameters are determined to obtain the minimum surface roughness. The measured roughness matches with the predicted roughness from the regression model. This proposed is proven and it can be further applied for optimizing other machining processes.

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Experiment-Based Process Modeling and Optimization for High-Quality and Resource-Efficient FFF 3D Printing

Applied Sciences ◽

10.3390/app10082899 ◽

2020 ◽

Vol 10 (8) ◽

pp. 2899 ◽

Cited By ~ 6

Author(s):

Ahmed Elkaseer ◽

Stella Schneider ◽

Steffen G. Scholz

Keyword(s):

Surface Roughness ◽

Energy Consumption ◽

3D Printing ◽

Layer Thickness ◽

Process Parameters ◽

Inclination Angle ◽

Dimensional Accuracy ◽

Surface Inclination ◽

Thick Layers ◽

Printing Speed

This article reports on the investigation of the effects of process parameters and their interactions on as-built part quality and resource-efficiency of the fused filament fabrication 3D printing process. In particular, the influence of five process parameters: infill percentage, layer thickness, printing speed, printing temperature, and surface inclination angle on dimensional accuracy, surface roughness of the built part, energy consumption, and productivity of the process was examined using Taguchi orthogonal array (L50) design of experiment. The experimental results were analyzed using ANOVA and statistical analysis, and the parameters for optimal responses were identified. Regression models were developed to predict different process responses in terms of the five process parameters experimentally examined in this study. It was found that dimensional accuracy is negatively influenced by high values of layer thickness and printing speed, since thick layers of printed material tend to spread out and high printing speeds hinder accurate deposition of the printed material. In addition, the printing temperature, which regulates the viscosity of the used material, plays a significant role and helps to minimize the dimensional error caused by thick layers and high printing speeds, whereas the surface roughness depends very much on surface inclination angle and layer thickness, which together determine the influence of the staircase effect. Energy consumption and productivity are primarily affected by printing speed and layer thickness, due to their high correlation with build time.

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Design of Experiment in the Milling Process of Aluminum Alloys in the Aerospace Industry

Applied Sciences ◽

10.3390/app10196951 ◽

2020 ◽

Vol 10 (19) ◽

pp. 6951

Author(s):

Aurel Mihail Țîțu ◽

Andrei Victor Sandu ◽

Alina Bianca Pop ◽

Ștefan Țîțu ◽

Dragos Nicolae Frățilă ◽

...

Keyword(s):

Surface Roughness ◽

Aluminum Alloy ◽

Central Composite Design ◽

End Milling ◽

Milling Process ◽

Depth Of Cut ◽

Main Task ◽

Advantages And Disadvantages ◽

Optimization Of Cutting Parameters ◽

Central Composite

For many years, surface has quality received a serious attention due to its influence on various mechanical properties. The main contribution made in this scientific paper is the performance of actual experiments, as well as the experimental processing obtained in order to develop a model for predicting the surface roughness based on the optimization of cutting parameters. The novelty of this paper is brought by the method of obtaining the regression equation of the surface roughness, resulted from a standard end-milling process (standard milling tools, standard milling parameters, recommended by the tool manufacturer, 3 axis CNC machine and standard vice), on aluminum alloy 7136 in temper T76511, through two statistical methods of data analysis. This material is used for the production of extruded parts and is poorly understood for the proposed line of research. This study’s aim is to determine the surface roughness equation obtained by the milling of aluminum alloy 7136 in two ways: using Taguchi′s experimental design once and the other, using the central composite design. The Taguchi method and the central composite design are used to develop an efficient mathematical model to predict the optimal level of certain processing parameters. Using ANOVA analysis, a comparative study of calculated and experimental surface roughness values is carried out. The initial characteristics (surface roughness) and the controlled factors (cutting speed, depth of cut and feed) are analyzed with the Minitab program. Finally, an analysis of the advantages and disadvantages of the two methods used is presented. This study has a great industrial application, since the main task of every manufacturer is to achieve a better quality of the final product with minimal processing time.

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