A study on the surface quality of the 3D printed parts caused by the scanning strategy

2019 ◽  
Vol 25 (2) ◽  
pp. 247-254 ◽  
Author(s):  
Jitai Han ◽  
Yanan Ge ◽  
Yuxin Mao ◽  
Meiping Wu
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Scanning Strategy ◽  
Clear Trend ◽  
Content Type ◽  
3D Printed ◽  
Side Face ◽  
Zigzag Shape ◽  
The Relationship

Purpose The purpose of this paper is to mainly focus on the relationship between the scanning strategy and surface quality. Surface quality, including surface roughness and flatness, is important for printed parts. So this paper optimizes the surface quality by changing the scanning strategy. Design/methodology/approach This paper is based on the phenomenon after the printed parts. A clear trend can be seen that the surface roughness on the side face shows a clear zigzag shape, so an optimized scanning strategy is used. Surface roughness in measured in macrostructure first by Mitutoyo and the flatness is measured by Hexagon Metrocogy. After that, microstructure on the side face is seen by RTEC to explain this phenomenon. Findings The surface quality on the side face shows a significant optimize by changing the scanning strategy. The surface quality on the positive face has some optimization to some degree. Originality/value This paper determines the relationship between the surface roughness on the side face and the scanning strategy. Few studies focus on the surface roughness, especially on the side face. Some studies try to optimize the surface roughness on the positive face. However, researchers always neglect the surface roughness on the side face. 2. This paper measures not only the surface roughness, but also the flatness. Surface roughness has a significant impact on the surface quality. However, it still has some limitations. Flatness is also measured to make this paper more representative. 3. This paper explains why scanning strategy can affect the surface quality. These images explain the research better and not just at the theoretical level.

The mechanism of process parameters influencing the AlSi10Mg side surface quality fabricated via laser powder bed fusion

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shimin Dai ◽  
Hailong Liao ◽  
Haihong Zhu ◽  
Xiaoyan Zeng
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Process Parameters ◽  
Laser Power ◽  
Side Surface ◽  
Laser Powder Bed Fusion ◽  
Scanning Velocity ◽  
Content Type ◽  
Powder Bed

Purpose For the laser powder bed fusion (L-PBF) technology, the side surface quality is essentially important for industrial applicated parts, such as the inner flow parts. Contour is generally adopted at the parts’ outline to enhance the side surface quality. However, the side surface roughness (Ra) is still larger than 10 microns even with contour in previous studies. The purpose of this paper is to study the influence of contour process parameters, laser power and scanning velocity on the side surface quality of the AlSi10Mg sample. Design/methodology/approach Using L-PBF technology to manufacture AlSi10Mg samples under different contour process parameters, use a laser confocal microscope to capture the surface information of the samples, and obtain the surface roughness Ra and the maximum surface height Rz of each sample after analysis and processing. Findings The results show that the side surface roughness decreases with the increase of the laser power at the fixed scanning velocity of 1,000 mm/s, the side surface roughness Ra stays within the error range as the contour velocity increases. It is found that the Ra increases with the scanning velocity increasing and the greater the laser power with the greater Ra increases when the laser power of contour process parameters is 300 W, 350 W and 400 W. The Rz maintain growth with the contour scanning velocity increasing at constant laser power. The continuous uniform contour covers the pores in the molten pool of the sample edge and thus increase the density of the sample. Two mechanisms named “Active adhesion” and “Passive adhesion” cause sticky powder. Originality/value Formation of a uniform and even contour track is key to obtain the good side surface quality. The side surface quality is determined by the uniformity and stability of the contour track when the layer thickness is fixed. These research results can provide helpful guidance to improve the surface quality of L-PBF manufactured parts.

scholarly journals Pseudo-random Path Generation Algorithms and Strategies for the Surface Quality Improvement of Optical Aspherical Components

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1216
Author(s):  
Jun Zha ◽  
Hangcheng Zhang ◽  
Yipeng Li ◽  
Yaolong Chen
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Path Generation ◽  
Optical Components ◽  
Validation Experiment ◽  
Polishing Path ◽  
Computer Controlled Optical Surfacing ◽  
The Relationship ◽  
Convolution Effect

This study proposes two path generation algorithms to diminish the superposition of the convolution effect on the polishing path in computer-controlled optical surfacing. According to the polishing of aluminum-alloy based hyperboloid optical components, different proportions of polishing agents were blended. Then, the surface roughness of the optical components were determined through a validation experiment of the algorithms. Furthermore, the relationship between surface roughness and the polishing agent concentration, and the compensation strategies for surface roughness were analyzed. The results show that the two algorithms effectively compensated for surface waviness. The findings support the strategies for improving the surface quality of optical components with aspherical surfaces.

scholarly journals A Proposed Scan Strategy Used on SLM Inner Structure Part

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 937 ◽  
Author(s):  
Jitai Han ◽  
Meiping Wu ◽  
Weipeng Duan
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Laser Energy ◽  
Side Surface ◽  
Test Results ◽  
New Strategy ◽  
Optimal Surface ◽  
The Relationship ◽  
Main Factor

A model with an inner structure was designed to study the relationship between the surface quality of the inner structure and the scan strategy in this study. The test results showed that the precision of the inner structure was highly affected by the scan strategy, and the specimens printed using different strategies showed different performances on the surface quality of the inner structure. The specimen printed using the square-framed scan strategy had a lower flatness value on the positive face of the inner structure compared to that of the other two specimens printed using Z-shape scan strategies, while the specimen printed using the Z-shape scan strategy (along the inner structure) had a relative optimal surface roughness on the side surface of the inner structure in all three specimens. The bending deformation caused by the scan strategies was considered to be the main factor affecting the flatness on the positive surface, while laser energy fluctuation showed a significant impact on side surface roughness. Combined with the experimental data, a new scan strategy was proposed; we found that the specimen printed using this new strategy improved positive surface flatness and side surface roughness.

Investigation on the relationship between bending angle of the overhanging surface and overhanging surface quality printed using selective laser melting

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Weipeng Duan ◽  
Jitai Han ◽  
Qingfneg Xia ◽  
Keqing Wang ◽  
Meiping Wu ◽  
...  
Keyword(s):  
Surface Quality ◽  
Molten Pool ◽  
Bending Angle ◽  
Content Type ◽  
Factors Affecting ◽  
Overall Performance ◽  
Increasing Demand ◽  
The Relationship ◽  
Bending Angles

Purpose With the increasing demand for lightweight parts, the quality of the inner structure gained growing attention from different kinds of fields. As the quality of the overhanging surface was one of the most important factors affecting inner structure formation, its quality still needs to improve. This paper aims to clarify the change of the overhanging surface quality caused by different bending angles. Design/methodology/approach The structure of the inner hole was redesigned according to the different performances of the overhanging and side inner surface. The experimental results revealed why different surface qualities can be seen under different bending angles. According to the experimental data, the inner structure was redesigned to increase its overall performance. Findings The results revealed that when the bending angle was small, the slope of the overhanging surface increased which lead to the decreasing length of the powder-supported layer. However, less space on bending angle resulted in the accumulation of unmelted powder which leads to the increasing of sinking distance. When the bending angle was too large, the slope of the overhanging surface decreased and the length of the molten pool which was supported by powder increased. It resulted in the sinking of the molten pool caused by the gravity of powder and its attachment. Originality/value This paper is the first work to study the relationship between bending angle and overhanging surface quality as far as the authors know. The different performances of left and right overhanging surfaces also have not been revealed in other research studies to the best of the knowledge.

Dry WEDM in Improving HS-WEDMed Surface Quality

2008 ◽  
Vol 392-394 ◽  
pp. 624-628 ◽  
Author(s):  
Tong Wang ◽  
Yu Mei Lu ◽  
Shuang Shuang Hao ◽  
Shu Qiang Xie ◽  
Xiao Cun Xu ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Material Removal ◽  
High Speed ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Dry Wedm ◽  
Finish Cut ◽  
The Relationship

This paper studies the surface quality of mould steel with high-speed wire electrical discharge machining (WEDM) method, which is conducted in gas to improve the accuracy of finish cut, and compares the surface quality in atmosphere and in emulsion dielectric. Experiment results showed that WEDM in atmosphere offers advantages such as better surface roughness and higher material removal rate. The relationship about winding speed and worktable feed on WEDMed surface quality in semi-finishing cut and finishing cut had been obtained. Morover, a new attemption was successful in applying dry WEDM in multiple cut to improve surface roughness.

scholarly journals Optimising the process parameters of selective laser melting for the fabrication of Ti6Al4V alloy

2018 ◽  
Vol 24 (1) ◽  
pp. 150-159 ◽  
Author(s):  
Zhonghua Li ◽  
Ibrahim Kucukkoc ◽  
David Z. Zhang ◽  
Fei Liu
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
High Surface ◽  
Optimum Process ◽  
Laser Melting ◽  
Vertical Side ◽  
Content Type

Purpose Surface roughness is an important evaluation index for industrial components, and it strongly depends on the processing parameters for selective laser molten Ti6Al4V parts. This paper aims to obtain an optimum selective laser melting (SLM) parameter set to improve the surface roughness of Ti6Al4V samples. Design/methodology/approach A response surface methodology (RSM)-based approach is proposed to improve the surface quality of selective laser molten Ti6Al4V parts and understand the relationship between the SLM process parameters and the surface roughness. The main SLM parameters (i.e. laser power, scan speed and hatch spacing) are optimized, and Ti6Al4V parts are manufactured by the SLM technology with no post processes. Findings Optimum process parameters were obtained using the RSM method to minimise the roughness of the top and vertical side surfaces. Obtained parameter sets were evaluated based on their productivity and surface quality performance. The validation tests have been performed, and the results verified the effectivity of the proposed technique. It was also shown that the top and vertical sides must be handled together to obtain better top surface quality. Practical implications The obtained optimum SLM parameter set can be used in the manufacturing of Ti6Al4V components with high surface roughness requirement. Originality/value RSM is used to analyse and determine the optimal combination of SLM parameters with the aim of improving the surface roughness quality of Ti6Al4V components, for the first time in the literature. Also, this is the first study which aims to simultaneously optimise the surface quality of top and vertical sides of titanium alloys.

Modeling for Prediction of Surface Roughness and Experimental Research in Ultra-Precision Flycutting Machining

2018 ◽  
Author(s):  
Jiasheng Li ◽  
Yang Jiao ◽  
Pinkuan Liu
Keyword(s):  
Surface Roughness ◽  
Prediction Model ◽  
Surface Quality ◽  
Cutting Parameters ◽  
Machining Parameters ◽  
Ultra Precision ◽  
Set Up ◽  
Validation Tests ◽  
The Relationship

To improve the surface quality of the copper and reduce the diamond tool wear, a prediction model is established experimentally for the relationship between surface roughness and machining parameters. Based on the processing principle of flycutting machining, the prediction model for surface roughness is set up by response surface methodology. Then, a machining experiment for the copper is conducted under different cutting parameters designed by Taguchi method and the surface roughness is tested by 4D technology dynamic laser interferometer. After that, the prediction model is obtained by analyzing the experimental data, and the accuracy of the model is verified by analysis of variance (ANOVA), R2 value and residual analysis. Furthermore, the effect of cutting parameters upon the surface roughness is analyzed. Finally, validation tests are conducted to verify the model. Experimental results demonstrate that the prediction model is adequate at 95% confidence level. The output of prediction model helps to select cutting parameters to reduce surface roughness which ensures surface quality in ultra-precision fly cutting machining.

scholarly journals Relationship of patient shame to working alliance and satisfaction: a preliminary investigation

2019 ◽  
Vol 14 (4) ◽  
pp. 251-263
Author(s):  
Daniel J. Carabellese ◽  
Michael J. Proeve ◽  
Rachel M. Roberts
Keyword(s):  
Patient Satisfaction ◽  
Working Alliance ◽  
Preliminary Investigation ◽  
Community Members ◽  
Content Type ◽  
Mediation Analyses ◽  
External Shame ◽  
Relationship Of ◽  
The Relationship

Purpose The purpose of this paper is to explore the relationship of two distinct variants of dispositional shame (internal and external shame) with collaborative, purpose-driven aspects of the patient–provider relationship (working alliance) and patient satisfaction. The aim of this research was to conduct a preliminary investigation into the relevance of dispositional shame in a general healthcare population. Design/methodology/approach In total, 127 community members (mean age 25.9 years) who reported that they had regularly seen a GP over the past year were recruited at an Australian university. Participants were asked to reflect on their relationship with their GP, and completed instruments assessing various domains of shame, as well as working alliance and patient satisfaction. Findings Non-parametric correlations were examined to determine the direction and strength of relationships, as well as conducting mediation analyses where applicable. Small, negative correlations were evident between external shame and working alliance. Both external and internal shame measures were also negatively correlated with patient satisfaction. Finally, the relationship of external shame to patient satisfaction was partially mediated by working alliance. Practical implications Both the reported quality of patient–provider working alliance, and level of patient satisfaction are related to levels of dispositional shame in patients, and working alliance may act as a mediator for this relationship. Originality/value The findings from this preliminary study suggest that internal and external shame are important factors to consider in the provision of medical care to maximise the quality of patient experience and working alliance.

Observation in the Surface Roughness of Silicon Wafer during Semi-Fixed Abrasive Machining with Large Grains

2009 ◽  
Vol 69-70 ◽  
pp. 253-257
Author(s):  
Ping Zhao ◽  
Jia Jie Chen ◽  
Fan Yang ◽  
K.F. Tang ◽  
Ju Long Yuan ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Silicon Wafer ◽  
Processing Parameters ◽  
Wafer Surface ◽  
Abrasive Machining ◽  
Fixed Abrasive ◽  
Is Failure ◽  
Better Than

Semi-fixed abrasive is a novel abrasive. It has a ‘trap’ effect on the hard large grains that can prevent defect effectively on the surface of the workpiece which is caused by large grains. In this paper, some relevant experiments towards silicon wafers are carried out under the different processing parameters on the semi-fixed abrasive plates, and 180# SiC is used as large grains. The processed workpieces’ surface roughness Rv are measured. The experimental results show that the surface quality of wafer will be worse because of higher load and faster rotating velocity. And it can make a conclusion that the higher proportion of bond of the plate, the weaker of the ‘trap’ effect it has. Furthermore the wet environment is better than dry for the wafer surface in machining. The practice shows that the ‘trap’ effect is failure when the workpiece is machined by abrasive plate which is 4.5wt% proportion of bond in dry lapping.

Quality of learning experience, student satisfaction and perceived overall experience in the COVID-19 context

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Venugopal Prabhakar Gantasala ◽  
Swapna Bhargavi Gantasala ◽  
Tareq Na'el Al Tawil ◽  
Prerana Prasad
Keyword(s):  
Higher Education ◽  
Student Satisfaction ◽  
Online Courses ◽  
Learning Experience ◽  
Decision Makers ◽  
Undergraduate Level ◽  
Content Type ◽  
The Relationship ◽  
Medical Programs

PurposeThe intention for this study was to explore any relationship that might exist between quality of learning experience (QLE), the second construct student satisfaction (SS) and the third construct perceived overall experience (POE) among undergraduate students within the higher education context. This study also attempts to explain the path direction between QLE, SS and POE.Design/methodology/approachThe researchers utilized structural equation modeling to analyze the variables considered for this study – QLE, SS and POE and for hypotheses testing. Respondents for this study were medical students' coordinators of the undergraduate level of medical colleges in the 28 states of India. Data collected for the study were possible by utilizing a questionnaire that was emailed to these student coordinators. The emailing effort returned 198 (n) filled questionnaires (complete) representing 198 institutions offering undergraduate-level medical programs out of a total of 542 institutions that offer undergraduate medical programs.FindingsFindings from this study confirm the relationship between QLE with SS, and PLE. Interestingly, the findings established a significant relationship between SS and POE.Practical implicationsDecision-makers and administrators of higher education institutions (HEIs) can utilize the findings from this study to focus on strengthening important elements of QLE in ways that positively impact SS and POE of students taking online courses and program offerings. The study reiterates the importance of course content, course structure, lecture-delivery quality, instructor mentoring and student-instructor interactions on SS and POE. The role of SS in reinforcing confirmation, perceived usefulness, perceived openness of the online courses and the perceived reputation was established. This relationship is key to administrators while they focus on improving SS and building on the institutions' reputation in addition to their efforts to support marketing and enrollments during the pandemic.Originality/valueResearchers in the past have examined the relationships between QLE and another construct of this study – SS. Past research has also examined the relationship between QLE and POE. However, there is not enough research exploring the relationship between SS and POE. This study establishes the relationship between SS and POE that benefits decision-makers in higher education.

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