Laser polishing to improve the surface quality of CoCr and Ti6AL4V additively manufactured parts

Author(s):  
Wojciech S. Gora ◽  
Yingtao Tian ◽  
Marcus Ardron ◽  
Philip Prangnell ◽  
Nicholas J. Weston ◽  
...  
Author(s):  
Jon Iñaki Arrizubieta ◽  
Magdalena Cortina ◽  
Jose Exequiel Ruiz ◽  
Aitzol Lamikiz

The present work proposes a novel manufacturing technique based on the combination of Laser Metal Deposition, Laser Beam Machining and Laser Polishing processes for the complete manufacturing of complex parts. Therefore, the complete process is based on the application of a laser heat source both for the building of the preform shape of the part by additive manufacturing and for the finishing operations. Their combination enables to manufacture near-net-shape parts and afterwards, remove the excess material via laser machining, which has resulted to be capable of eliminating the waviness resulting from the additive process. Besides, surface quality is improved via laser polishing to reduce the roughness of the final part. Therefore, conventional machining operations are eliminated, what results in a much cleaner process. In order to validate the capability of this new approach, the dimensional accuracy and surface quality of the resulting parts are evaluated. The process has been validated on an Inconel 718 test part, where a previously additively built up part has been finished by means of laser machining and laser polishing.


2016 ◽  
Vol 22 (6) ◽  
pp. 956-964 ◽  
Author(s):  
Benoit Rosa ◽  
Pascal Mognol ◽  
Jean-Yves Hascoët

Purpose Direct metal deposition (DMD) with laser is an additive manufacturing process enabling rapid manufacturing of complex metallic and thin parts. However, the final quality of DMD-manufactured surfaces is a real issue that would require a polishing operation. Polishing processes are usually based on abrasive or chemical techniques. These conventional processes are composed by many drawbacks such as accessibility of complex shapes, environmental impacts, high time consumption and cost, health risks for operators, etc. […] This paper aims to solve these problems and improve surface quality by investigating the laser polishing (LP) process. Design/methodology/approach Based on melting material by laser, the LP process enables the smoothing of initial topography. However, the DMD process and the LP processes are based on laser technology. In this context, the laser DMD process is used directly on the same machine for the polishing operation. Currently, few studies focus on LP of additive laser manufacturing surfaces, and it tends to limit the industrial use of additive manufacturing technology. The proposed study describes an experimental analysis of LP surfaces obtained by DMD process. Findings The investigation results in the improvement of a complete final surface quality, according to LP parameters. For mastering LP processes, operating parameters are modelled. Originality/value This experimental study introduces the LP of thin and complex DMD parts, to develop LP applications. The final objective is to create a LP methodology for optimizing the final topography and productivity time according to parts’ characteristics.


2020 ◽  
Vol 110 (11-12) ◽  
pp. 838-843
Author(s):  
Philipp Müller ◽  
Bernd-Arno Behrens ◽  
Sven Hübner ◽  
Hendrik Vogt ◽  
Daniel Rosenbusch ◽  
...  

Techniken zur Steigerung der Formgebungsgrenzen in der Umformtechnik sind von hoher wirtschaftlicher Bedeutung. In dieser Arbeit wird eine Schwingungsüberlagerung im Krafthauptfluss eines Axialformprozesses zur Ausprägung einer Verzahnungsgeometrie untersucht. Die Auswirkungen der Schwingung auf die erzielbare Ausfüllung der Zahnkavitäten werden analysiert sowie die Parameter Schmierung und Oberflächengüte der Halbzeuge in ihrer kombinierten Wirkung untersucht. Es konnte eine Reduzierung der mittleren Umformkraft sowie eine Erhöhung der Formfüllung festgestellt werden. Techniques for extending the production limits in forming technology are of great economic importance. In this research, a superimposed oscillation in the main force flow of an axial forming process to form an axial gear geometry is investigated. The effects of the superimposed oscillation on the achievable form-filling of the tooth cavities are analyzed and the parameters lubrication and surface quality of the semi-finished products are investigated in their combined effect. A reduction of the averaged forming force as well as an increase of the form-filling could be achieved.


2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Xu Zhao ◽  
Yadong Gong ◽  
Guiqiang Liang ◽  
Ming Cai ◽  
Bing Han

AbstractThe existing research on SiCp/Al composite machining mainly focuses on the machining parameters or surface morphology. However, the surface quality of SiCp/Al composites with a high volume fraction has not been extensively studied. In this study, 32 SiCp/Al specimens with a high volume fraction were prepared and their machining parameters measured. The surface quality of the specimens was then tested and the effect of the grinding parameters on the surface quality was analyzed. The grinding quality of the composite specimens was comprehensively analyzed taking the grinding force, friction coefficient, and roughness parameters as the evaluation standards. The best grinding parameters were obtained by analyzing the surface morphology. The results show that, a higher spindle speed should be chosen to obtain a better surface quality. The final surface quality is related to the friction coefficient, surface roughness, and fragmentation degree as well as the quantity and distribution of the defects. Lower feeding amount, lower grinding depth and appropriately higher spindle speed should be chosen to obtain better surface quality. Lower feeding amount, higher grinding depth and spindle speed should be chosen to balance grind efficiently and surface quality. This study proposes a systematic evaluation method, which can be used to guide the machining of SiCp/Al composites with a high volume fraction.


2011 ◽  
Vol 233-235 ◽  
pp. 2714-2717
Author(s):  
Xin Gang Ai ◽  
Sheng Li Li ◽  
Dong Wei Zhang ◽  
Nan Lv ◽  
Jun Tao

Huge rectangular ingots becomes crying needs in the condition of lots of heavy plate mills more than 5m have been in operation. In this paper, a special method of wind cooling outside mould has been presented and applied to produce 60t rectangular ingot. Mathematical simulation results tell us that by wind cooling, the solidification time of the 60t ingot can be shortened by 67 minutes, internal soundness can be ensured. The wind cooling process can obviously improve microstructure and preventing skull patch by increasing the thickness of solidified shell. A 60 tons huge rectangular ingot is successfully produced by wind cooling, the surface quality of is very well and the internal soundness should be improved further.


e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 519-527
Author(s):  
Wei Gong ◽  
Xianglin Pei ◽  
Xiaogang Yin ◽  
Daming Ban ◽  
Hai Fu ◽  
...  

AbstractIn this paper, acrylonitrile and hydroxypropyl acrylate are used as the binary polymerization monomers, and isooctane is used as the foaming agent to prepare high-temperature thermally expandable microcapsules. Analysis of the effect of blowing agent and crosslinking agent on the expansion properties of high-temperature thermally expandable microcapsules, the effects of foaming agent azodicarbonamide (ADCA) and micro-expansion capsule on the surface quality and foaming quality of foamed acrylonitrile–butadiene–styrene (ABS) products were investigated. The foamed product prepared by the high-temperature microcapsule has a good surface quality, the gloss is 52.3, the cell is not easily deformed, and the volume fraction is 4%; the foamed ABS/ADCA material has poor cell uniformity, the cell is easily deformed, the volume fraction is 6.5%, the surface quality is poor, and the gloss is only 8.7.


Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 393
Author(s):  
Jiantao Zhou ◽  
Xu Han ◽  
Hui Li ◽  
Sheng Liu ◽  
Shengnan Shen ◽  
...  

Laser polishing is a widely used technology to improve the surface quality of the products. However, the investigation on the physical mechanism is still lacking. In this paper, the established numerical transient model reveals the rough surface evolution mechanism during laser polishing. Mass transfer driven by Marangoni force, surface tension and gravity appears in the laser-induced molten pool so that the polished surface topography tends to be smoother. The AlSi10Mg samples fabricated by laser-based powder bed fusion were polished at different laser hatching spaces, passes and directions to gain insight into the variation of the surface morphologies, roughness and microhardness in this paper. The experimental results show that after laser polishing, the surface roughness of Ra and Sa of the upper surface can be reduced from 12.5 μm to 3.7 μm and from to 29.3 μm to 8.4 μm, respectively, due to sufficient wetting in the molten pool. The microhardness of the upper surface can be elevated from 112.3 HV to 176.9 HV under the combined influence of the grain refinement, elements distribution change and surface defects elimination. Better surface quality can be gained by decreasing the hatching space, increasing polishing pass or choosing apposite laser direction.


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