scholarly journals Simultaneous Nano-Texturing onto a CVD-Diamond Coated Piercing Punch with Femtosecond Laser Trimming

2020 ◽  
Vol 10 (8) ◽  
pp. 2674 ◽  
Author(s):  
Tatsuhiko Aizawa ◽  
Tomomi Shiratori ◽  
Yoshihiro Kira ◽  
Tadahiko Inohara
Keyword(s):  
Femtosecond Laser ◽  
Surface Quality ◽  
Chemical Vapor ◽  
Side Surface ◽  
Chemical Vapor Deposition Diamond ◽  
Diamond Coating ◽  
Periodic Surface ◽  
Femtosecond Laser Processing ◽  
Edge Profile

In this study, a CVD (Chemical Vapor Deposition)-diamond coated tungsten carbide cobalt (WC (Co)) punch was trimmed to adjust its surface roughness and to significantly reduce its edge curvature for fine piercing by femtosecond laser processing. Through this laser trimming, the surface quality of the diamond coating and the punch edge profile were improved to less than 0.5 μm at the maximum roughness and 2 μm in the edge width, respectively. In parallel with this improvement of surface quality, the side surface of the diamond coating was modified to include nano-textures via the LIPSS (Laser Induced Periodic Surface Structuring) process. Through the fine piercing process, this nanotexture was transcribed onto the pierced hole surface together with fine shearing of the hole by piercing. WLI (White-Light Interferometry) and SEM (Scanning Electron Microscopy) were utilized to describe this transcription of nanotextures during the piercing process. These semiregular nanotextures with an LIPSS period of 300 nm on the pierced hole surface induced a blue colored surface plasmon.

scholarly journals Femtosecond Laser Trimming with Simultaneous Nanostructuring to Fine Piercing Punch to Electrical Amorphous Steel Sheets

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 568
Author(s):  
Tatsuhiko Aizawa ◽  
Tomomi Shiratori ◽  
Yoshihiro Kira ◽  
Tomoaki Yoshino ◽  
Yohei Suzuki
Keyword(s):  
Femtosecond Laser ◽  
Chemical Vapor ◽  
Side Surface ◽  
Edge Condition ◽  
Sintered Alloy ◽  
Chemical Vapor Deposition Diamond ◽  
Layer Width ◽  
Steel Sheets ◽  
Edge Profile ◽  
Amorphous Steel

A CVD (Chemical Vapor Deposition) diamond coated tungsten carbide (WC) and cobalt (Co) sintered alloy punch was trimmed by the femtosecond laser machining to sharpen its edge with about 2 μm and to simultaneously make nanostructuring to its side surface. In addition to the sharpened edge, its edge profile was formed to be homogeneous enough to reduce the damage layer width by piercing the electrical amorphous steel sheet stack. Each brittle sheet in the stacked work was damaged to have three kinds of defects by piercing; e.g., the droop-like cracking in the thickness and at the vicinity of hole, the wrinkling in peak-to-valley with partial cracking on the peaks, and the circumferential cracking. When using the WC (Co) punch with the inhomogeneous edge profile in the sharpened edge width, these three damages were induced into each sheet and the maximum damage width exceeded 80 μm. When using the punch with the sharpened edge and homogeneous edge profile, the wrinkling mode was saved and the total affected layer width was significantly reduced to less than 20 μm. Through the precise embossing experiments, this effect of punch edge profile condition to the induced damages was discussed with a statement on the nanostructuring effect on the reduction of damaged width in electrical amorphous steel sheets. The developed tool with the sharpened edge and homogenous edge condition contributes to the realization of a low iron loss motor with a reduced affected layer width.

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.

Influence of polarization state on surface quality of femtosecond laser ablation quartz glass

2014 ◽  
Vol 26 (2) ◽  
pp. 21006
Author(s):  
吴东江 Wu Dongjiang ◽  
姚龙元 Yao Longyuan ◽  
马广义 Ma Guangyi ◽  
郭东明 Guo Dongming
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Surface Quality ◽  
Quartz Glass ◽  
Polarization State ◽  
Femtosecond Laser Ablation

Ultrafast Dynamics of Sub-Wavelength Periodic Surface Structuring during Femtosecond Laser Processing of Dielectrics

2014 ◽  
Vol 1035 ◽  
pp. 426-431
Author(s):  
Yan Ping Yuan ◽  
Ji Min Chen ◽  
Fu Rong Liu
Keyword(s):  
Femtosecond Laser ◽  
Laser Fluence ◽  
Chemical Characteristic ◽  
Quantum Model ◽  
Electron Dynamics ◽  
Periodic Surface ◽  
Ablation Crater ◽  
Surface Structuring ◽  
Femtosecond Laser Processing ◽  
Sub Wavelength

A femtosecond laser pulse duration is shorter than many physical/chemical characteristic times, which makes it possible to control electron dynamics such as ionizations and electron densities. This study expermetally investigtes the effects of laser fluence on sub-wavelength periodic surface structuring based on ultrafast laser electron dynamics control. A quantum model for the sub-wavelength periodic surface structuring is also proposed, which considers both the wave properties in the photon particle-properties based plasma model for photon-electron interactions and transient localized changes of material properties. It shows that the laser fluence strongly affects the ablation crater shapes. The prediction of ablation crater shape and periodicity is in agreement with experimental data.

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.

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