scholarly journals Experimental studies of the quality of embossed characters of the Braille alphabet

2016 ◽  
Vol 64 (3) ◽  
pp. 607-614
Author(s):  
R. Barczyk ◽  
D. Jasińska-Choromańska
Keyword(s):  
Surface Roughness ◽  
Statistical Analysis ◽  
3D Printing ◽  
Rapid Prototyping ◽  
Experimental Studies ◽  
Printed Text ◽  
Blind Persons ◽  
Blind Individuals

Abstract The paper presents studies pertaining to the quality of embossed characters of the Braille alphabet used, among other applications, for tagging drug labels. The following parameters of embossed inscriptions were measured: height, diameter of the dots and surface roughness (18 samples with various combinations of their values). 48 blind individuals assessed the quality of the printed text. Statistical analysis proved that a text with dots having height of 0.9 millimeter, diameter of 1.6 millimeters and roughness Ra of about 1 micrometer to be the best. The samples had been made using two different methods of rapid prototyping: PolyJet and SLS. 3D printing is increasingly popular and the studies proved the usefulness of these methods for labeling with embossed inscriptions, due to the repeatability, durability and quality they ensure. The assessing group of blind individuals was comprised of 24 persons 14–17 years old and other 24 persons aged over 60 who were not proficient in reading Braille alphabet, This allows to conclude that a text featuring the above values of the parameters will be easy to read for the majority of blind persons.

Statistical Analysis of Process Parameters in Drilling of Al/Al2O3p Metal Matrix Composites

2014 ◽  
Vol 14 (3) ◽  
pp. 171-175 ◽  
Author(s):  
Yashvir Singh ◽  
Amneesh Singla ◽  
Ajay Kumar
Keyword(s):  
Surface Roughness ◽  
Statistical Analysis ◽  
Process Parameters ◽  
Metal Matrix ◽  
Design Method ◽  
Experimental Studies ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
Signal To Noise ◽  
Drilling Parameters

AbstractThis paper presents a statistical analysis of process parameters for surface roughness in drilling of Al/Al2O3p metal matrix composite. The experimental studies were conducted under varying spindle speed, feed rate, point angle of drill. The settings of drilling parameters were determined by using Taguchi experimental design method. The level of importance of the drilling parameters is determined by using analysis of variance. The optimum drilling parameter combination was obtained by using the analysis of signal-to-noise ratio. Through statistical analysis of response variables and signal-to-noise ratios, the determined significant factors are depth of cut and drill point angle with the contributions of 87% and 12% respectively, whereas the cutting speed is insignificant contributing by 1% only. Confirmation tests verified that the selected optimal combination of process parameter through Taguchi design was able to achieve desired surface roughness.

scholarly journals Surface Roughness Investigation of Poly-Jet 3D Printing

Mathematics ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1758
Author(s):  
Nectarios Vidakis ◽  
Markos Petousis ◽  
Nikolaos Vaxevanidis ◽  
John Kechagias
Keyword(s):  
Surface Roughness ◽  
3D Printing ◽  
Surface Quality ◽  
Back Propagation ◽  
Physical Models ◽  
Layer By Layer ◽  
Linear Regression Models ◽  
Feed Forward Back Propagation ◽  
The Impact

An experimental investigation of the surface quality of the Poly-Jet 3D printing (PJ-3DP) process is presented. PJ-3DP is an additive manufacturing process, which uses jetted photopolymer droplets, which are immediately cured with ultraviolet lamps, to build physical models, layer-by-layer. This method is fast and accurate due to the mechanism it uses for the deposition of layers as well as the 16 microns of layer thickness used. Τo characterize the surface quality of PJ-3DP printed parts, an experiment was designed and the results were analyzed to identify the impact of the deposition angle and blade mechanism motion onto the surface roughness. First, linear regression models were extracted for the prediction of surface quality parameters, such as the average surface roughness (Ra) and the total height of the profile (Rt) in the X and Y directions. Then, a Feed Forward Back Propagation Neural Network (FFBP-NN) was proposed for increasing the prediction performance of the surface roughness parameters Ra and Rt. These two models were compared with the reported ones in the literature; it was revealed that both performed better, leading to more accurate surface roughness predictions, whilst the NN model resulted in the best predictions, in particular for the Ra parameter.

scholarly journals The Influence of Different Slicer Software on 3d Printing Products Accuracy and Surface Roughness

2021 ◽  
Vol 12 (2) ◽  
pp. 371-380
Author(s):  
Sally Cahyati ◽  
◽  
Haris Risqy Aziz
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
3D Printing ◽  
3D Model ◽  
High Surface ◽  
3D Printer ◽  
Layer By Layer ◽  
Additive Manufacturing Technology ◽  
Printing Machine

Rapid Prototyping (RP) is a manufacturing process that produces a 3D model CAD to be a real product rapidly by using additive manufacturing technology. In this case, the product will print layer by layer uses a 3D printer machine. The 3D printer requires slicer software to convert CAD data into data that a 3D printer machine can read. Research is done to analyze the effect of three kinds of slicer software on 3D printing objects on the accuracy and surface roughness of the product. The 3D model CAD is sliced using three different slicer software, namely Ideamaker, Repetier Host, and Cura. The slice model result from each slicer will be printed on a 3D printer machine with the same process parameters to be compared. Then the product's dimensional and surface roughness will be measured to determine the effect of each slicer on product quality. The best quality of the product reflected the most suitable slicer software for the 3D printing machine that used. The best results achieved by Cura slicer because it has resulted in small dimensional deviations (max 0,0308±0,0079) and stabile high surface roughness of the product (max 1,585+059).

scholarly journals Comparison of Ankle Proprioception Between Blind and Healthy Athletes

2014 ◽  
Vol 2 (11_suppl3) ◽  
pp. 2325967114S0015
Author(s):  
Muhammet Özer ◽  
Haydar Kaynak ◽  
Aziz Atik ◽  
Mehtap Kaçmaz Şilil ◽  
Muammer Altun ◽  
...  
Keyword(s):  
Plantar Flexion ◽  
Position Sense ◽  
Joint Position Sense ◽  
Athletic Department ◽  
Eyes Closed ◽  
Eyes Open ◽  
Blind Persons ◽  
Ankle Proprioception ◽  
Blind Individuals

Objectives: The positive effect of the visual sensation on the proprioceptive quality is well known. Although other senses of the congenital blind individuals have been proven to be increased more than healthy ones, there has been no data about the proprioceptive quality of congenital blind persons. The aim of this study is to determine the quality of ankle proprioception in congenital blind athletes. Methods: 15 congenital blind athletes (10 males and 5 females) with a mean age of 24 ± 2.9 (ranging from 20 to 29), and 15 healthy athletes (10 males and 5 females) with a mean age of 24.6 ± 3.05 (ranging from 20 to 29), from the same athletic department, were included in the study. Proprioception was evaluated by using the technique of joint position sense, and absolut errors during the reproduction of six target angles (plantar flexion 100, dorsiflexion 50, inversion 100 and 200, eversion 100 and 200) were detected in dominant and nondominant ankles of both groups. Athletes were measured both eyes open and closed. Statistical analysis was done by using Mann-Whitney U and Wilcoxon Signed Ranks tests. Results: When dominant extremities were compared while eyes open, there was only a difference in 50 dorsiflexion measurements statistically in favor of blind ones (p<0.05). When dominant extremities were compared while eyes closed, blind athletes got less wrong in four of the six target angles statistically (p<0.01), when non-dominant extremities were compared while eyes closed, blind athletes got less wrong in all angles statistically (p<0.01). The ankle proprioception of the blind athletes were better then the normal athletes. The ankle propriceptions of the normal athletes further deteriorated when their eyes were closed. Conclusion: We found that the ankle proprioceptions of congenital blind athletes were better than the normal athletes. So additional closed-eyes exercises can help to reach a high proprioceptive level of athletes in a normal season which in terms may decrease accidental traumas.

Effect of Printing Temperature on Mechanical Properties and Surface Quality of Photosensitive Resin Rapid Prototyping Parts

2017 ◽  
Vol 727 ◽  
pp. 466-470
Author(s):  
Xian Yong Zhu ◽  
Fei Fei Cui ◽  
Cheng Jiang ◽  
Dong Ni Geng ◽  
Xue Lei Xu ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Rapid Prototyping ◽  
Bending Strength ◽  
Bending Tests ◽  
Bending Modulus ◽  
C 23 ◽  
Photosensitive Resin ◽  
Tensile Elastic Modulus ◽  
C 30

Abstract. The rapid prototypes of different printing temperature by Objet30 Stratasys Pro printer were found a certain difference in performance in the process of using the process.In order to studied the effect of printing temperature on the rapid prototyping of photosensitive resin, tensile and bending tests were carried out on the rapid prototyping parts at 12°C, 18°C, 21°C, 23°C, 25°C, 30°C,respectively,and the rigidity and surface roughness of rapid prototyping parts were measured.Research shows：the tensile strength increases with the increase of printing temperature , tensile elastic modulus fluctuates with the printing temperature , they all increases rapidly after 25°C;The bending strength increases proportional with the increase of printing temperature, and the bending modulus increases first and then tends to decrease with the increase of printing temperature;The hardness value increases slowly with the increase of printing temperature, and increases obviously after 20°C,the hardness value in the middle of the prototype parts is bigger than the edge parts；The surface roughness with increasing printing temperature, although it is floating up and down, but have little effect.

scholarly journals Evaluation and optimisation of a slurry-based layer casting process in additive manufacturing using multiphase simulations and spatial reconstruction

2021 ◽  
Author(s):  
P. Erhard ◽  
A. Seidel ◽  
J. Vogt ◽  
W. Volk ◽  
D. Günther
Keyword(s):  
Surface Roughness ◽  
3D Printing ◽  
Fine Particles ◽  
High Surface ◽  
Casting Process ◽  
Spatial Reconstruction ◽  
Novel Method ◽  
Slurry Layer ◽  
High Level

AbstractSlurry-based 3D printing allows ceramic green bodies to be fabricated at high packing densities. In contrast to powder-based binder jetting, full densification of printed parts can be achieved in a subsequent sintering step as fine particles dispersed in a suspension are cast and compacted. Slurry-based 3D printing is thus expected to overcome the application limits of the powder-based alternative in metal casting in terms of unfavorable properties like high surface roughness, low density and low mechanical strength. To ensure stress-free drying and therefore high qualities of the compounds made in layers, it is crucial to fabricate single layers with a high level of homogeneity. This paper presents a CFD model based on the open-source simulation environment OpenFOAM to predict the resulting homogeneity of a cast slurry layer with defined parameter sets or coater geometries using the Volume-Of-Fluid method. Moreover, a novel method of spatial reconstruction is proposed to evaluate the surface quality of layers on a minimised computional demand. By comparing the results of the simulation with the real macroscopic behaviour determined in experiments, the approach is found to be a useful tool for suggesting suitable parameters and coater geometries for processing slurries. A precise reconstruction of the outline of the coating area with different process parameters and an approximate prediction of the effect on surface roughness was achieved.

scholarly journals Thermal Stress Flow Analysis in Fabrication of Acetabular Shells Using SLM

2017 ◽  
Vol 2 (2) ◽  
pp. 297 ◽  
Author(s):  
Amir Mahyar Khorasani ◽  
Ian Gibson ◽  
Moshe Goldberg ◽  
Mohammad Masoud Movahedi ◽  
Guy Littlefair
Keyword(s):  
Thermal Stress ◽  
Additive Manufacturing ◽  
3D Printing ◽  
Rapid Prototyping ◽  
Hip Replacement ◽  
Raw Material ◽  
Energy Beam ◽  
Acetabular Shell ◽  
Stress Flow

<p>Additive Manufacturing (AM), more popularly known as 3D Printing, is a process for producing functional artifacts by adding layers of materials from data generated directly from 3D solid CAD models. Additive Manufacturing (AM) is the formalized term for what used to be called Rapid Prototyping and what is commonly referred to as 3D Printing. The key to how AM works is that parts are made by adding layers of material; each layer corresponding to a thin cross-section of the part derived from the original CAD data. Although most AM machines produce parts using polymers, there are an increasing number of machines that can directly fabricate in metals. The majority of these machines fabricate from raw material in powder form using a directed energy beam to create a local melt zone. Total hip replacement is recommended for people who have medical issues related to excessive wear of the acetabular, osteoarthritis, accident or age. Researches have shown that large numbers of hip arthroplasties (where the articular surface of a musculoskeletal joint is replaced), hip remodelling, or realignment are carried out annually and will increase in the next few decades. Manufacturing of acetabular shells by using AM is a promising and emerging method that has a great potential to improve public health. Lost wax casting or investment casting is currently used to produce acetabular shells followed by lengthy and complex secondary processes such as machining and polishing. Living organs and medical models have intricate 3D shapes that are challenging to identity in X-ray CT images. These images are used for preparing treatment plans to improve the quality of the surgeries regarding waiting and surgery time per procedure and care regime. For instance, a limited number of hip replacement procedures can be carried out on each acetabulum due to a decrease of bone thickness. Rapid prototyping is a suitable treatment planning tool in complex cases to enhance the quality of surgical procedure and provide long-term stability that can be used to customize the shape and size of the acetabular shell. In this paper, to analyse the manufacturing of a prosthetic acetabular shell, built-up lines resulting from a thermal stress flow and process stopping during the selective laser melting (SLM) AM process, with regarding Gibbs free energy, interfacial energy, and equilibrium temperature will be discussed. Geometrical measurements showed 1.59% and 0.27% differences between the designed and manufactured prototype for inside and outside diameter respectively. Experimental results showed that thermal stress flow in outer surfaces are compressive, but for inner surfaces are tensile, so built-up lines in inner and outer surfaces appear as a groove and dent respectively. The results also indicate that SLM is an accurate and promising method for fabrication of acetabular cup.</p>

The effects of 3D printing in design thinking and design education

2016 ◽  
Vol 14 (4) ◽  
pp. 752-769 ◽  
Author(s):  
Scott Greenhalgh
Keyword(s):  
3D Printing ◽  
Rapid Prototyping ◽  
Design Process ◽  
Interior Design ◽  
Medium Effect ◽  
Design Technology ◽  
Content Type ◽  
3D Printed ◽  
Design Students

Purpose Rapid prototyping and three-dimensional (3D) printing allows the direct creation of objects from 3D computer-aided design files. To identify the effects 3D printing may have on student experiences and the learning of the design process, students were asked to create a design and create a prototype of that design. Design/methodology/approach This study follows an experimental design involving four total courses of interior design students. After conceptualizing a design, students were randomly selected to either create the prototype by hand or given access to 3D printing equipment. The models were graded by three subject experts using a rubric that focused on three key aspects of the model project, namely, craftsmanship, design quality and scale (proportion). Findings All three measures produced significant mean differences with a medium effect size when comparing the 3D printed models to the traditionally built models. Additional observations provided insights into the design processes approached by students using hand-constructed and 3D printed modeling. The most notable difference was the propensity for curved and rectilinear shapes by available design technologies. Research limitations/implications The experiment showed that the design technology (3D printing) did have an impact on the designs students conceptualized. This suggests that students do connect ideation to implementation, and the availability of enabling technology impacts the design process. This research was conducted in an interior design environment and consists of primarily female students. The experimental research may be limited to design programs with similar student populations and levels of exposure to various design technologies. Practical implications This research is designed to provide instructors and programs valuable information when looking at implementing new design technologies into the curriculum. Instructors are made aware that new design technologies do impact student design strategies. Additionally, although certain design technologies allow for revisions, it was apparent that students continued to be resistant to revise their initial models suggesting instructors prepare to address this issue in instruction. Social implications There is a strong body of research indicating inequality in education where students have differing access to technologies in schools. This research shows that 3D printing, similar to many technologies in education, can impact the cognitive processes of content being learned. Originality/value There is limited research on how design technologies impact design cognition and the experiences of design students. This paper looked specifically at one design technology (3D printing/rapid prototyping) and how it impacts the processes and quality of design, in addition to the quality of design products (prototypes or models). Research such as this provides instructors and faculty members an insight into how design technologies impact their curriculum.

Actively Cooled and Activated Coolant for Grinding Brittle Materials

2008 ◽  
Vol 389-390 ◽  
pp. 338-343 ◽  
Author(s):  
Y. Gao ◽  
J. Xin ◽  
H. Lai
Keyword(s):  
Surface Roughness ◽  
Surface Morphology ◽  
Surface Quality ◽  
Experimental Studies ◽  
Brittle Materials ◽  
Cryogenic Cooling ◽  
Experimental Results ◽  
Cooling Method ◽  
Cooling Methods

An actively cooled and activated cooling approach is proposed and examined in this project in order to deal with the problems associated with methods such as the cryogenic cooling method. It is also aimed to further improve the surface quality of the workpiece after grinding by combining the advantages of the existing cooling methods. Both computational and experimental studies were conducted for grinding the brittle materials with the proposed approach. Optical examinations were used to study the surface morphology. The experimental results show that the surface quality can be improved by up to 23.75% on average in terms of surface roughness Ra. The computational test reveals that the heat can be taken away more effectively by the proposed approach.

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