scholarly journals Effects of Post-Treatment to Improve the Surface Quality of 3D Printing Cement Mold Casting

2021 ◽  
Vol 11 (24) ◽  
pp. 11824
Author(s):  
Seung-Yeop Chun ◽  
Geumyeon Lee ◽  
Su-jin Kim ◽  
Bora Jeong ◽  
Jeehoon Shin ◽  
...  
Keyword(s):  
Surface Roughness ◽  
3D Printing ◽  
Surface Quality ◽  
Post Treatment ◽  
Silica Sand ◽  
Gas Generation ◽  
Powder Bed ◽  
Aluminum Castings ◽  
Mold Casting ◽  
Spherical Silica

Powder bed 3D printing can be applied to sandcasting mold manufacturing to ensure high quality and economy through process innovation. In this study, refractory alumina cement was used as an aqueous binder to ensure high-temperature thermal stability to minimize the addition of organic matter to reduce gas generation. In addition, spherical silica sand, the study material, was selected to a size of 30 µm to improve the casting mold resolution. To improve the surface quality through the post-treatment process, we confirmed the change in the surface roughness of the mold depending on the surface treatment of colloidal silica and the presence or absence of heat treatment, and finally made the mold through actual casting. Changes in the surface roughness and flowability of the cast body after mold post-treatment were confirmed. For aluminum castings, the shrinkage rate and surface roughness were confirmed in a box-shaped mold via gravity casting, and the flowability of the molten metal in the mold was confirmed in a hand-shaped mold. There was a change in the roughness and porosity of the mold, owing to the post-treatment, and the influence of the surface roughness and flowability of the cast body during actual casting was confirmed.

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 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 Pandora’s Box–Influence of Contour Parameters on Roughness and Subsurface Residual Stresses in Laser Powder Bed Fusion of Ti-6Al-4V

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3348
Author(s):  
Katia Artzt ◽  
Tatiana Mishurova ◽  
Peter-Philipp Bauer ◽  
Joachim Gussone ◽  
Pere Barriobero-Vila ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Surface Quality ◽  
Powder Bed Fusion ◽  
Fuel Injector ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Melt Pool ◽  
Contour Lines ◽  
High Laser

The contour scan strategies in laser powder bed fusion (LPBF) of Ti-6Al-4V were studied at the coupon level. These scan strategies determined the surface qualities and subsurface residual stresses. The correlations to these properties were identified for an optimization of the LPBF processing. The surface roughness and the residual stresses in build direction were linked: combining high laser power and high scan velocities with at least two contour lines substantially reduced the surface roughness, expressed by the arithmetic mean height, from values as high as 30 µm to 13 µm, while the residual stresses rose from ~340 to about 800 MPa. At this stress level, manufactured rocket fuel injector components evidenced macroscopic cracking. A scan strategy completing the contour region at 100 W and 1050 mm/s is recommended as a compromise between residual stresses (625 MPa) and surface quality (14.2 µm). The LPBF builds were monitored with an in-line twin-photodiode-based melt pool monitoring (MPM) system, which revealed a correlation between the intensity quotient I2/I1, the surface roughness, and the residual stresses. Thus, this MPM system can provide a predictive estimate of the surface quality of the samples and resulting residual stresses in the material generated during LPBF.

scholarly journals A Study of the Surface Deterioration due to Erosion

1983 ◽  
Author(s):  
W. Tabakoff ◽  
C. Balan
Keyword(s):  
Surface Roughness ◽  
Wind Tunnel ◽  
Surface Quality ◽  
Engine Performance ◽  
Silica Sand ◽  
Particulate Flow ◽  
Heavy Oils ◽  
Synthetic Fuels ◽  
Combustion Gases

Turbomachines are subject to excessive rate of erosion when operated in dusty environments or exposed to combustion gases of newly developed synthetic fuels or heavy oils. The surface quality of the blades exposed to such particulate flow deteriorates. With time, the surface roughness increases and leads to a decrease in engine performance. This paper presents the results of the experiments carried out in an erosion wind tunnel on 6061T6 aluminum specimens to study the roughness formations. The particles used were silica sand.

scholarly journals De-Powdering Effect of Foundry Sand for Cement Casting

2021 ◽  
Vol 12 (1) ◽  
pp. 266
Author(s):  
Seungyeop Chun ◽  
Geumyeon Lee ◽  
Sujin Kim ◽  
Bora Jeong ◽  
Jeehoon Shin ◽  
...  
Keyword(s):  
3D Printing ◽  
Silica Sand ◽  
Powder Layer ◽  
Test Results ◽  
Binding Properties ◽  
Powder Bed ◽  
3D Printed ◽  
New Research ◽  
Aluminate Cement ◽  
Thermal Stability Of

With the development of the powder bed 3D printing process, sand casting can be performed with methods that are more advanced than the traditional ones, thus enabling new research on applied materials. When sand is 3D-printed with cement as a binder, its casting performance is improved and sufficient thermal stability of conventional organic and inorganic binders is ensured. In this study, to ensure high resolution and strength in a physical and simple mixture of cement and sand, the compatibility for casting was confirmed using submicron-level cement with ingredients and sizes similar to commercial sand, which is uniformly controlled at 4 µm, instead of conventional sand. To enable quick 3D printing, calcium aluminate cement, which has quick binding properties, was used for high-temperature casting. The strength up to 6 h after hydration was compared to determine the curing rate of silica, mullite, and alumina sand containing cement components. By investigating the change in strength due to heat treatment and comparing the adhesion drop test results after powder bed formation, the material containing silica sand was determined as the most suitable for powder layer 3D printing for application to the mold.

A Study of the Surface Deterioration due to Erosion

1983 ◽  
Vol 105 (4) ◽  
pp. 834-838 ◽  
Author(s):  
W. Tabakoff ◽  
C. Balan
Keyword(s):  
Surface Roughness ◽  
Wind Tunnel ◽  
Surface Quality ◽  
Engine Performance ◽  
Silica Sand ◽  
Particulate Flow ◽  
Heavy Oils ◽  
Synthetic Fuels ◽  
Combustion Gases

Turbomachines are subject to an excessive rate of erosion when operated in dusty environments or exposed to combustion gases of newly developed synthetic fuels or heavy oils. The surface quality of the blades exposed to such particulate flow deteriorates. With time, the surface roughness increases and leads to a decrease in engine performance. This paper presents the results of the experiments carried out in an erosion wind tunnel on 6061T6 aluminum specimens to study the roughness formations. The particles used were silica sand.

scholarly journals Laser Polishing of Laser Powder Bed Fusion AlSi10Mg Parts—Influence of Initial Surface Roughness on Achievable Surface Quality

2021 ◽  
Vol 12 (01) ◽  
pp. 15-41
Author(s):  
Markus Hofele ◽  
Andre Roth ◽  
Jochen Schanz ◽  
David K. Harrison ◽  
Anjali K. M. De Silva ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Initial Surface ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Laser Polishing

scholarly journals On the Relevance of Volumetric Energy Density in the Investigation of Inconel 718 Laser Powder Bed Fusion

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 538 ◽  
Author(s):  
Fabrizia Caiazzo ◽  
Vittorio Alfieri ◽  
Giuseppe Casalino
Keyword(s):  
Surface Roughness ◽  
Energy Density ◽  
Process Parameters ◽  
Vickers Hardness ◽  
Powder Bed Fusion ◽  
Processing Conditions ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Fractional Density ◽  
Experimental Variation

Laser powder bed fusion (LPBF) can fabricate products with tailored mechanical and surface properties. In fact, surface texture, roughness, pore size, the resulting fractional density, and microhardness highly depend on the processing conditions, which are very difficult to deal with. Therefore, this paper aims at investigating the relevance of the volumetric energy density (VED) that is a concise index of some governing factors with a potential operational use. This paper proves the fact that the observed experimental variation in the surface roughness, number and size of pores, the fractional density, and Vickers hardness can be explained in terms of VED that can help the investigator in dealing with several process parameters at once.

scholarly journals Mechanical Characterization and Thermodynamic Analysis of Laser-Polished Landscape Design Products Using 3D Printing

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2601
Author(s):  
Yue Ba ◽  
Yu Wen ◽  
Shibin Wu
Keyword(s):  
Surface Roughness ◽  
3D Printing ◽  
Fused Deposition Modeling ◽  
High Surface ◽  
Landscape Design ◽  
Laser Polishing ◽  
Fused Deposition ◽  
Design Structure ◽  
3D Printed ◽  
Stability And Accuracy

Recent innovations in 3D printing technologies and processes have influenced how landscape products are designed, built, and developed. In landscape architecture, reduced-size models are 3D-printed to replicate full-size structures. However, high surface roughness usually occurs on the surfaces of such 3D-printed components, which requires additional post-treatment. In this work, we develop a new type of landscape design structure based on the fused deposition modeling (FDM) technique and present a laser polishing method for FDM-fabricated polylactic acid (PLA) mechanical components, whereby the surface roughness of the laser-polished surfaces is reduced from over Ra 15 µm to less than 0.25 µm. The detailed results of thermodynamics and microstructure evolution are further analyzed during laser polishing. The stability and accuracy of the results are evaluated based on the standard deviation. Additionally, the superior tensile and flexural properties are examined in the laser-polished layer, in which the ultimate tensile strength (UTS) is increased by up to 46.6% and the flexural strength is increased by up to 74.5% compared with the as-fabricated components. Finally, a real polished landscape model is simulated and optimized using a series of scales.

scholarly journals Improving surface quality in selective laser melting based tool making

2021 ◽  
Author(s):  
Filippo Simoni ◽  
Andrea Huxol ◽  
Franz-Josef Villmer
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Melting Process ◽  
Laser Remelting ◽  
Laser Melting ◽  
Great Cost ◽  
Starting Point ◽  
Processing Techniques

AbstractIn the last years, Additive Manufacturing, thanks to its capability of continuous improvements in performance and cost-efficiency, was able to partly replace and redefine well-established manufacturing processes. This research is based on the idea to achieve great cost and operational benefits especially in the field of tool making for injection molding by combining traditional and additive manufacturing in one process chain. Special attention is given to the surface quality in terms of surface roughness and its optimization directly in the Selective Laser Melting process. This article presents the possibility for a remelting process of the SLM parts as a way to optimize the surfaces of the produced parts. The influence of laser remelting on the surface roughness of the parts is analyzed while varying machine parameters like laser power and scan settings. Laser remelting with optimized parameter settings considerably improves the surface quality of SLM parts and is a great starting point for further post-processing techniques, which require a low initial value of surface roughness.

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