scholarly journals Effect of Powder Feeding Rate on the Forming Quality of Alloy by Laser Melting Deposition

2021 ◽  
Vol 2083 (2) ◽  
pp. 022024
Author(s):  
Chenghong Duan ◽  
Yinzhou Zhang ◽  
Xiangpeng Luo
Keyword(s):  
Surface Quality ◽  
Feeding Rate ◽  
Granular Bainite ◽  
Single Track ◽  
Laser Melting ◽  
Forming Quality ◽  
Metallurgical Bonding ◽  
Laser Melting Deposition ◽  
Powder Feeding

Abstract 12CrNi2 alloy steel was prepared by Laser Melting Deposition (LMD) technology, and the effect of powder feeding rate on surface quality, internal defects, microstructure, and microhardness of the single track and manufactured part were investigated. The results show that the metallurgical bonding of the single track deteriorates, the surface quality of the manufactured part is improved, the average microhardness of the manufactured part increases, and the number of pores first decreases and then increases with the increase of powder feeding rate. At the lower powder feeding rate, the manufactured parts have larger pore defects, while at the higher powder feeding rate, the manufactured parts have poor fusion defects. The main phase composition of the manufactured parts is ferrite(F), granular bainite (GB), and pearlite(P), and the manufactured part has finer grains at the higher powder feeding rate.

scholarly journals Effect of Process Parameters and Layer Thickness on the Quality and Performance of Ti-6Al-4V Fabricated by Selective Laser Melting

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1323
Author(s):  
Yanlong Jing ◽  
Peng Wang ◽  
Xiaoling Yan
Keyword(s):  
Surface Quality ◽  
Selective Laser Melting ◽  
Exposure Time ◽  
Process Parameters ◽  
Laser Power ◽  
Single Track ◽  
Laser Melting ◽  
Powder Bed ◽  
Point Distance

To improve the quality of thick powder bed and realize the matching of thick powder bed and thin powder bed in the later stage, the influence of process parameters for the single-track, multi-layer fabrication, relative density, surface quality, defect, remelting, and boundary optimization performance of different layer thicknesses of Ti-6Al-4V fabricated by selective laser melting were investigated. It is more conducive to the stable forming of single-track when the point distance is half the diameter of the laser beam, and the exposure time is appropriately extended. The thin powder bed needs the corresponding point distance and exposure time under the laser power of 280–380 W to obtain high-density specimens. The thick powder bed needs to be able to ensure the formation of high-quality specimens under the smaller point distance and longer exposure time under higher laser power of 380 W. Both thick powder bed and thin powder bed will cause un-melted defects between molten pools, spheroidization defects caused by splashing, and microporous defects. The remelting process can significantly improve the surface quality of the formed specimen, but the surface quality of the thick powder bed is worse than that of the thin powder bed. The boundary quality of thick powder bed is worse than that of thin powder bed, and the boundary shape has a greater influence on the quality of the SLM forming boundary. Different strategies should be adopted to form the boundary of different shapes. Increasing the boundary count and increasing the laser power are more conducive to the improvement of boundary quality.

Effect of process parameters on formability and surface quality of selective laser melted Al-Zn-Sc-Zr alloy from single track to block specimen

2019 ◽  
Vol 118 ◽  
pp. 132-139 ◽  
Author(s):  
Jiang Bi ◽  
Zhenglong Lei ◽  
Yanbin Chen ◽  
Xi Chen ◽  
Xikun Qin ◽  
...  
Keyword(s):  
Surface Quality ◽  
Process Parameters ◽  
Single Track ◽  
Zr Alloy

scholarly journals The Influence of Process Parameters and Scanning Strategy on Lower Surface Quality of TA15 Parts Fabricated by Selective Laser Melting

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1228
Author(s):  
Junjie Jiang ◽  
Jianming Chen ◽  
Zhihao Ren ◽  
Zhongfa Mao ◽  
Xiangyu Ma ◽  
...  
Keyword(s):  
Surface Quality ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Flexible Manufacturing ◽  
Molten Pool ◽  
Lower Surface ◽  
Laser Melting ◽  
Scanning Strategy ◽  
Influence Of Process Parameters

With superior flexible manufacturing capability, selective laser melting (SLM) has attracted more and more attention in the aerospace, medical, and automotive industries. However, the poor quality of the lower surface in overhanging structures is still one of the factors that limits the wide application of SLM. In this work, the influence of process parameters and scanning strategy on the lower surface quality of SLMed TA15 (Ti-6Al-2Zr-1Mo-1V) titanium alloy parts were studied. The results showed that the laser surface energy density (EF) had a significant influence on the quality of the lower surface. Excessive EF led to obvious sinking of the molten pool and a serious slag hanging phenomenon. However, the too low EF easily contributed to the insufficient powder fusion in the lower surface area, which led to the agglomeration of a molten pool during core processing, resulting in slag hanging, pores, and powder spalling that reduced the quality of the lower surface. Moreover, the cross-remelting strategy and non-remelting strategy gained better surface quality at the low EF and high EF, respectively. In addition, it was found that the quality of the lower surface could be quickly and accurately evaluated by the cooling time of the molten pool during the processing of the lower surface. This research can increase the understanding of the forming mechanism of the lower surface and has certain guiding significance for the process optimization of the lower surface.

The Key Technology in Extrusion Tapping of Internal Thread

2011 ◽  
Vol 295-297 ◽  
pp. 2636-2641 ◽  
Author(s):  
Yong Yi Li ◽  
Sheng Dun Zhao
Keyword(s):  
Surface Quality ◽  
Automotive Industry ◽  
Hole Diameter ◽  
Internal Thread ◽  
Processing Efficiency ◽  
Forming Quality ◽  
Key Technology ◽  
Modern Manufacturing ◽  
Traditional Process

Internal thread processing is an indispensable procedure in manufacture, its processing efficiency and quality become more and more important in modern manufacturing, especially in aerospace and automotive industry. Compared with the traditional process of cut tapping of internal thread, the process of extrusion tapping of internal thread possesses the following advantages: without chip, higher precision, better surface quality, better continuity of metallic, greater efficient, greater strength, longer tool life. This paper firstly introduces the current research status of extrusion tapping of internal thread, elaborates the principle and characteristic of extrusion tapping, analyzes the matal plastic flow law and thread forming characteristic during tapping, then generalizes the influencing law of the key technology on thread forming quality, such as extrusion tap type, lead hole diameter, tapping speed and friction. Furthermore, puts forward some improvement approach to reduce tapping torque and enhance forming quality of internal thread.

scholarly journals Influence of Laser Energy in the Surface Quality of Parts Manufactured by Selective Laser Melting

2018 ◽  
pp. 0279-0286 ◽  
Author(s):  
Pablo Zapico ◽  
Sara Giganto ◽  
Susana Martinez Pellitero ◽  
Ana Isabel Fernandez - Abia ◽  
Maria Angeles Castro Sastre
Keyword(s):  
Surface Quality ◽  
Selective Laser Melting ◽  
Laser Energy ◽  
Laser Melting

Forming Quality of Titanium Alloys by Selective Laser Melting Based on Partition Scanning

2018 ◽  
Vol 55 (9) ◽  
pp. 091401
Author(s):  
万乐 Wan Le ◽  
王思琦 Wang Siqi ◽  
张晓伟 Zhang Xiaowei ◽  
蒋业华 Jiang Yehua
Keyword(s):  
Titanium Alloys ◽  
Selective Laser Melting ◽  
Laser Melting ◽  
Forming Quality

Research on Catalyst Penetration Process of Patternless Casting Manufacturing Technique

2014 ◽  
Vol 609-610 ◽  
pp. 1515-1520 ◽  
Author(s):  
Wei Dong Yang ◽  
Zhan Qun Shi ◽  
Li Li
Keyword(s):  
Rapid Prototyping ◽  
Surface Quality ◽  
Dimensional Accuracy ◽  
Single Droplet ◽  
Forming Process ◽  
Penetration Process ◽  
Forming Quality ◽  
Main Factors ◽  
Sand Particles

Pattenless Casting Manufacturing (PCM) technique is a kind of Rapid Prototyping based on droplet injection, using discrete nozzle to jet the catalyst. The quality of scanning lines has the most important effect on the sand strength, its surface quality and dimensional accuracy. The penetration and curing rules of the catalyst in the resined-sand particles are the main factors to determine the shape of the scanning lines. In order to study the penetration rules of the catalyst in the resined-sand, the penetration process of a single droplet and scanning lines are analyzed theoretically and verified by experiments. The important parameters of the forming process are determined based on the research and experimental results. It will provide the foundation to improve the forming quality of PCM technique.

Theoretical and experimental study on surface roughness of 316L stainless steel metal parts obtained through selective laser melting

2016 ◽  
Vol 22 (4) ◽  
pp. 706-716 ◽  
Author(s):  
Di Wang ◽  
Yang Liu ◽  
Yongqiang Yang ◽  
Dongming Xiao
Keyword(s):  
Surface Roughness ◽  
Energy Density ◽  
Surface Quality ◽  
Theoretical Foundation ◽  
Laser Energy ◽  
Melting Zone ◽  
Laser Energy Density ◽  
Single Track ◽  
Laser Melting ◽  
Content Type

Purpose The purpose of this paper is to provide a theoretical foundation for improving the selective laser melting (SLM) surface roughness. To improve the part’s surface quality during SLM process, the upper surface roughness of SLM parts was theoretically studied and the influencing factors were analyzed through experiments. Design/methodology/approach The characteristics of single track were first investigated, and based on the analysis of single track, theoretical value of the upper surface roughness would be calculated. Two groups of cubic sample were fabricated to validate SLM parts’ surface roughness, the Ra and relative density of all the cubic parts was measured, and the difference between theoretical calculation and experiment results was studied. Then, the effect of laser energy density on surface roughness was studied. At last, the SLM part’s surface was improved by laser re-melting method. At the end of this paper, the curved surface roughness was discussed briefly. Findings The SLM upper surface roughness is affected by the width of track, scan space and the thickness of powder layer. Measured surface roughness Ra value was about 50 per cent greater than the theoretical value. The laser energy density has a great influence on the SLM fabrication quality. Different laser energy density corresponds to different fabricating characteristics. This study divided the SLM fabrication into not completely melting zone, balling zone in low energy density, successfully fabricating zone and excessive melting zone. The laser surface re-melting (LSR) process can improve the surface roughness of SLM parts greatly without considering the fabricating time and stress accumulation. Originality/value The upper surface roughness of SLM parts was theoretically studied, and the influencing factors were analyzed together; also, the LSR process was proven to be effective to improve the surface quality. This study provides a theoretical foundation to improve the surface quality of SLM parts to promote the popularization and application of metal additive manufacturing technology.

Experimental Investigation into the Single-Track of Selective Laser Melting of IN625

2011 ◽  
Vol 233-235 ◽  
pp. 2844-2848 ◽  
Author(s):  
Li Wang ◽  
Qing Song Wei ◽  
Yu Sheng Shi ◽  
Jin Hui Liu ◽  
Wen Ting He
Keyword(s):  
Energy Density ◽  
Relative Density ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Laser Power ◽  
Laser Energy ◽  
Scanning Speed ◽  
Single Track ◽  
Laser Melting ◽  
Metallic Parts

Selective laser melting(SLM) is driven by the need to fabricate functional metallic parts and tools with near shape and density. The method of process to fabricate a metal part will save materials, time and energy compared to the traditional manufacturing methods. Unlike the selective laser sintering (SLS), the metal powder particles are molten by the laser beam during the process of selective laser melting. In this paper, IN625 powders were adopted to investigate the characters of single molten track. The factors that affect the surface quality and relative density are the process parameters such as the laser energy, scan speed and so on. They were studied to find out the correlation between the parameters and formation of single-track. It has been found that Optimal ratio between laser power and scanning speed (P/v) is 1-1.5 for IN625 SLM. P/v is the linear energy density. It also has been found that the width and height of single-track can be calculated when the linear energy density is given. In this study the laser power, scan spacing and the hatch spacing which affect the surface quality and the relative density of the metallic parts were optimized.

Sign in / Sign up

Export Citation Format

Share Document