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3rd International Conference on Material Engineering and Advanced Manufacturing Technology, 26–28 April 2019, Shanghai, China
- 2020
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Proceedings (redaktörskap) (refereegranskat)abstract
- We are very pleased to present the proceedings of the 3rd International Conference on Material Engineering and Advanced Manufacturing Technology (MEAMT 2019) that was held successfully under the auspices of IASED in Shanghai, China, April 26-28, 2019.The theme of the conference - Material Engineering and Advanced Manufacturing Technology - is of key importance to the science and technology and a sustainable industrial development. This conference promotes valuable contacts between academia and industry and addresses both basic research and the societal/industrial technological needs within Material Engineering and Advanced Manufacturing Technology.In this era of Industry 4.0, we hope that the conference provided applicable data/information, addressed the issues in the societal/industrial transformation, and facilitated exchange within and between academia and industry.We want to express our gratitude to the program chairs and all members of the advisory, publicity, and technical committees for their valuable time and advices. We are grateful to the world renowned scientists who acted as keynote speakers at the conference.After a rigorous review process, where each paper was reviewed by at least two reviewers, high quality papers were accepted for presentation at this conference. We would like to thank all the reviewers for their time, effort, and for completing their assignments on time albeit tight deadlines.Many thanks to the authors for their valuable contributions and to the attendees for their active participation.Finally, a big thank to the organizers who made this conference to yet another unforgettable experience.Nader AsnafiProfessor of Mechanical Engineering, Örebro University, Sweden Editor of the proceedings of MEAMT 2019 One behalf of the conference committee.
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- Sadeghimeresht, Esmaeil, 1985-, et al.
(författare)
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Isothermal Oxidation Behavior of EBM-Additive Manufactured Alloy 718
- 2018
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Ingår i: Proceedings of the 9th International Symposium on Superalloy 718 & Derivatives. - Cham : Springer. - 9783319894799 - 9783319894805 ; , s. 219-240
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Konferensbidrag (refereegranskat)abstract
- Oxidation of Alloy 718 manufactured by electron beam melting (EBM) process has been undertaken in ambient air at 650, 700, and 800 °C for up to 168 h. At 800 °C, a continuous external chromia oxide enriched in (Cr, Ti, Mn, Ni) and an internal oxide that was branched structure of alumina formed, whereas at 650 and 700 °C, a continuous, thin and protective chromia layer was detected. The oxidation kinetics of the exposed EBM Alloy 718 followed the parabolic rate law with an effective activation energy of ~248 ± 22 kJ/mol in good agreement with values in the literature for conventionally processed chromia-forming Ni-based superalloys. The oxide scale formed on the surface perpendicular to the build direction was slightly thicker, and more adherent compared to the scale formed on the surface along the build direction, attributed to the varied grain texture in the two directions of the EBM-manufactured specimens. The increased oxygen diffusion and high Cr depletion found on the surface along the build direction were attributed to the fine grains and formation of vacancies/voids along this grain orientation.
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- Vallabani, N. V. Srikanth, et al.
(författare)
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Toxicity evaluation of particles formed during 3D-printing : Cytotoxic, genotoxic, and inflammatory response in lung and macrophage models
- 2022
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Ingår i: Toxicology. - : Elsevier BV. - 0300-483X .- 1879-3185. ; 467
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Tidskriftsartikel (refereegranskat)abstract
- Additive manufacturing (AM) or "3D-printing" is a ground-breaking technology that enables the production of complex 3D parts. Its rapid growth calls for immediate toxicological investigations of possible human exposures in order to estimate occupational health risks. Several laser-based powder bed fusion AM techniques are available of which many use metal powder in the micrometer range as feedstock. Large energy input from the laser on metal powders generates several by-products, like spatter and condensate particles. Due to often altered physicochemical properties and composition, spatter and condensate particles can result in different toxicological responses compared to the original powder particles. The toxicity of such particles has, however, not yet been investigated. The aim of the present study was to investigate the toxicity of condensate/spatter particles formed and collected upon selective laser melting (SLM) printing of metal alloy powders, including a nickel-chromiumbased superalloy (IN939), a nickel-based alloy (Hastelloy X, HX), a high-strength maraging steel (18Ni300), a stainless steel (316L), and a titanium alloy (Ti6Al4V). Toxicological endpoints investigated included cytotoxicity, generation of reactive oxygen species (ROS), genotoxicity (comet and micronucleus formation), and inflammatory response (cytokine/chemokine profiling) following exposure of human bronchial epithelial cells (HBEC) or monocytes/macrophages (THP-1). The results showed no or minor cytotoxicity in the doses tested (10 100 mu g/mL). Furthermore, no ROS generation or formation of micronucleus was observed in the HBEC cells. However, an increase in DNA strand breaks (detected by comet assay) was noted in cells exposed to HX, IN939, and Ti6Al4V, whereas no evident release of pro-inflammatory cytokine was observed from macrophages. Particle and surface characterization showed agglomeration in solution and different surface oxide compositions compared to the nominal bulk content. The extent of released nickel was small and related to the nickel content of the surface oxides, which was largely different from the bulk content. This may explain the limited toxicity found despite the high Ni bulk content of several powders. Taken together, this study suggests relatively low acute toxicity of condensates/spatter particles formed during SLM-printing using IN939, HX, 18Ni300, 316L, and Ti6Al4V as original metal powders.
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- Asnafi, Nader, 1960-, et al.
(författare)
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3D Metal Printing from an Industrial Perspective : Product Design, Production, and Business Models
- 2019
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Ingår i: Berg- und Huttenmännische Monatshefte (BHM). - Vienna : Springer. - 0005-8912 .- 1613-7531. ; 164:3, s. 91-100
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Tidskriftsartikel (refereegranskat)abstract
- This paper is focused on automotive stamping tools and dies as well as the impact of 3D metal printing and metals related 3D-printing on design and production of such tools and dies. The purpose has been to find out the current industrial potential of 3D-printing as far as lead time, costs, shapes, material usage, metal piece size, surface roughness, hardness, strength, and machinability are concerned. The business transformational impact of 3D-printing is also addressed in this paper. The obtained results show that the lead time can be halved, the costs are somewhat higher, and the strength, hardness, surface roughness, and machinability of the 3D-printed metallic tools and dies are as good as those of the conventionally made. The maximum size of a metal piece that can be 3D-printed today by Powder Bed Fusion (PBF) is, in the best case, 500 mm × 500 mm × 500 mm. 3D-printing can also be used for the pattern to make the mold box in iron and steel casting. It is also possible to eliminate the casting pattern, since the mold box can be 3D-printed directly. All this has started to have a large business impact, and it is therefore of great significance to outline and execute an action plan almost immediately.
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- Asnafi, Nader, 1960-, et al.
(författare)
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Laser surface-hardening of dies for cutting, blanking or trimming of uncoated DP600
- 2004
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Ingår i: Proceedings of the International Conference on Recent Advances in Manufacture and Use of Tools and Dies and Stamping of Steel Sheets. - Olofström : Vovo Cars. ; , s. 193-214
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Konferensbidrag (refereegranskat)abstract
- In this study, the methods used to harden trim dies were at the focus. Laser surface-hardening was compared to induction- and through-hardening for small and medium-size series production. The sheet materials used were 1.2 mm thick uncoated Docol 600DP and 1.95 mm thick uncoated Docol 600DL The die materials tested were Fermo, Canmo and Sleipner. This investigation showed that the optimum laser-hardening parameters must be established for each trim die material. The trim die in laser-hardened Sleipner exhibits the smallest wear, whilst the trim die in induction-hardened Fermo displays the largest wear in the semi-industrial phase of this study. The magnitude of this largest wear is, however, very small. The trim die in induction-hardened Fermo managed 100 000 strokes without any problem. The dimensional changes after laser hardening are very small. The burr height is very small, regardless of how the trim die is hardened. In this study, two sets of production trim dies were manufactured and set up. This production trim dies are used in the manufacture of V70 B-pillar Left and Right Laser hardening resulted in a lead time reduction by 5 labour days. However, the Tool & Die unit estimates that the lead time reduction obtained with laser hardening should be around 10 days under normal conditions. The cost analysis conducted by the Tool & Die unit shows that the manufacturing costs are reduced by 6%, if laser-hardening is selected. These production trim dies are and will be monitored continuously. As this paper is being written, these dies have been subject to 50 000 strokes.
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- Asnafi, Nader, 1960-
(författare)
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Tubular Hydroforming and Hydropiercing
- 2019
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Ingår i: Sustainable Material Forming and Joining. - Boca Raton : CRC Press. - 9781351670319
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Bokkapitel (refereegranskat)abstract
- Hydroforming of tubular components has been known by many other names such as bulge forming of tubes, hydrobulging, internal high-pressure forming, liquid forming of tubular components, etc. Different “hydroforming” methods have been reported earlier. Hydroforming or expansion in an open and in a closed tool (Dohmann and Hartl, 1996), free and die-bound hydroforming (Schäfer Hydroforming, 1996), low, high and sequenced pressure forming (Mason, 1996; VARI-FORM, 1996), and the Rolls–Royce method (Astrop, 1968) are some of the different methods tested, used, and reported so far.
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- Kang, Byung-Soo, et al.
(författare)
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The effect of calcium ion concentration on the bone response to oxidized titanium implants
- 2012
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Ingår i: Clinical Oral Implants Research. - Malden, USA : Wiley-Blackwell. - 0905-7161 .- 1600-0501. ; 23:6, s. 690-697
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To investigate the effect of calcium concentration on the bone tissue response to Ca-incorporated titanium implants.Materials and methods: Two titanium surfaces containing 4.2% and 6.6% calcium were prepared using the micro-arc oxidation process. The implants were inserted in the tibia of nine New Zealand White rabbits. After 6 weeks of healing, the bone response to the implants was quantitatively compared by biomechanical and histomorphometrical measurements.Results: Ca 4.2% and Ca 6.6% containing implants revealed no distinctive differences in their qualitative surface chemistry; chemical bonding state of Ca in titanium oxide was mainly calcium titanates. No significant differences were observed between two implants in peak removal torque and shear strength comparisons (P>0.05). Histomorphometrical analyses presented no significant differences in bonemetal contact, bone area and newly formed bone measurements between two implants (P>0.05).Conclusions: From biomechanical and histomorphometrical measurements, the two calcium concentrations in this study did not differ significantly with respect to their influence on the bone tissue response. This similar bone response in rabbit tibiae may be explained by the similarity of the qualitative Ca chemistry in titanium surfaces.
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- Rahayem, Mohamed R., 1978-, et al.
(författare)
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Quadric segmentation and fitting of data captured by a laser profile scanner mounted on an industrial robot
- 2010
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Ingår i: The International Journal of Advanced Manufacturing Technology. - Berlin : Springer London. - 0268-3768 .- 1433-3015. ; 52:1-4, s. 155-169
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Tidskriftsartikel (refereegranskat)abstract
- Applications like geometric reverse engineering, robot vision and automatic inspection require sets of points to be measured from the surfaces of objects and then processed by segmentation and fitting algorithms to establish shape parameters of interest. In industrial applications where speed, reliability and automatic operation is of interest a measuring system based on a laser profile scanner mounted on an industrial robot can be of interest. In earlier publications we have presented such a system and also a segmentation algorithm for planar surfaces using 2D profile data in combination with robot poses. Due to the data reduction offered by this approach the segmentation algorithm computes faster than algorithms based on 3D point sets alone. Encouraged by the results we have now developed a segmentation algorithm for two different quadric surfaces also based on 2D profiles in combination with robot poses. This paper presents the new algorithm together with test results and also an interesting observation that points to future work.
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