Surface quality inspection using a laser beam with a regular dynamic interference pattern

1993 ◽  
Author(s):  
Vladimir P. Ryabukho ◽  
Yuri A. Avetisyan ◽  
Andrey E. Grinevich ◽  
Dmitry A. Zimnyakov ◽  
Boris V. Feduleev ◽  
...  
Keyword(s):  
Laser Beam ◽  
Surface Quality ◽  
Interference Pattern ◽  
Quality Inspection ◽  
Dynamic Interference

The Influence of Laser Beam Technological Parameters on the Polymethyl Methacrylate Surface Quality

2018 ◽  
Vol 919 ◽  
pp. 190-198 ◽  
Author(s):  
Vladimír Pata ◽  
Libuše Sýkorová ◽  
Oldřich Šuba ◽  
Milena Kubišová
Keyword(s):  
Regression Analysis ◽  
Statistical Analysis ◽  
Laser Beam ◽  
Surface Quality ◽  
Polymethyl Methacrylate ◽  
Quality Parameters ◽  
Technological Parameters ◽  
Detailed Statistical Analysis ◽  
Mathematical Relations

The paper is focused on the determination of the course and change of the surface quality parameters obtained by the laser engraving of the material known under commercial name polymethyl methacrylate. The paper aims to find mathematical relations based on regression analysis for amplitudes parameters Ra and Rz. For this purpose, a sample of variable technology parameters will be machined followed by the surface measuring and evaluation using the Talysurf CLI 500 3D Surface Scanner. Thus the data obtained will be subjected to the detailed statistical analysis to check homoscedasticity, the presence of outliers, and multidimensional normality testing.

Investigation of Sectoral Scanning in Selective Laser Melting

2010 ◽  
Author(s):  
Evren Yasa ◽  
Jan Deckers ◽  
Jean-Pierre Kruth ◽  
Marleen Rombouts ◽  
Jan Luyten
Keyword(s):  
Mechanical Properties ◽  
Residual Stresses ◽  
Laser Beam ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Random Order ◽  
Laser Source ◽  
Metal Powders ◽  
Laser Melting ◽  
Powder Bed

Selective laser melting (SLM), a powder metallurgical (PM) additive manufacturing (AM) technology, is able to produce fully functional parts directly from standard metal powders without using any intermediate binders or any additional post-processing steps. During the process, a laser beam selectively scans a powder bed according to the CAD data of the part to be produced and completely melts the powder particles together. Stacking and bonding two-dimensional powder layers in this way, allows production of fully dense parts with any geometrical complexity. The scanning of the powder bed by the laser beam can be achieved in several different ways, one of which is island or sectoral scanning. In this way, the area to be scanned is divided in small square areas (‘sectors’) which are scanned in a random order. This study is carried out to explore the influence of sectoral scanning on density, surface quality, mechanical properties and residual stresses formed during SLM. The experiments are carried out on a machine with an Nd:YAG laser source using AISI 316L stainless steel powder. As a result of this experimental study, it is concluded that sectoral scanning has some advantages such as lower residual stresses and better surface quality. However, the selection of parameters related to sectoral scanning is a critical task since it may cause aligned porosity at the edges between sectors or scanned tracks, which is very undesired in terms of mechanical properties.

Influence of overlap between the laser beam tracks on surface quality in laser polishing of AISI H13 tool steel

2012 ◽  
Vol 14 (4) ◽  
pp. 425-434 ◽  
Author(s):  
Abdullah M. Khalid Hafiz ◽  
Evgueni V. Bordatchev ◽  
Remus O. Tutunea-Fatan
Keyword(s):  
Laser Beam ◽  
Surface Quality ◽  
Tool Steel ◽  
Laser Polishing ◽  
H13 Tool Steel ◽  
Aisi H13 ◽  
Aisi H13 Tool Steel

Signal Analysis of Scratch-Detection on Magnetic Disc by Using Light Reflection Approach

2015 ◽  
Vol 781 ◽  
pp. 203-206 ◽  
Author(s):  
Achinee Polsawat ◽  
Nattawoot Suwannata ◽  
Apirat Siritaratiwat ◽  
Anan Kruesubthaworn
Keyword(s):  
Laser Beam ◽  
Signal Analysis ◽  
Quality Inspection ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Recording Head ◽  
Process Machinery ◽  
Magnetic Disc ◽  
Non Destructive ◽  
Scratch Detection

In hard disk manufacturing, a process of quality inspection of magnetic disc is crucially focused on finding traces of scratch that occur on the surface by various sources such as production process, machinery, tribology or recording head. It may affect the efficiency of magnetic disc’s read/write ability. Many approaches have been proposed to detect the scratch by either destructive or non-destructive testing. In this study, it shows an analysis of signals from the detected scratches on the magnetic disc by reflection light method, using a CD pick-up head. It works by producing an incidental laser beam to the surface and then detecting it by a photodiode detector. The results showed that when the laser beam is incident onto the magnetic disc with/ without scratch, reflecting lights to the photodiode are different and the signal changes according to the intensity of the incidental/reflecting lights.

Influence of laser parameters and Ti content on the surface morphology of L-PBF fabricated Titania

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Abid Ullah ◽  
HengAn Wu ◽  
Asif Ur Rehman ◽  
YinBo Zhu ◽  
Tingting Liu ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Laser Beam ◽  
Surface Quality ◽  
Selective Oxidation ◽  
Laser Power ◽  
Scanning Speed ◽  
Content Type ◽  
Powder Bed ◽  
Laser Parameters

Purpose The purpose of this paper is to eliminate Part defects and enrich additive manufacturing of ceramics. Laser powder bed fusion (L-PBF) experiments were carried to investigate the effects of laser parameters and selective oxidation of Titanium (mixed with TiO2) on the microstructure, surface quality and melting state of Titania. The causes of several L-PBF parts defects were thoroughly analyzed. Design/methodology/approach Laser power and scanning speed were varied within a specific range (50–125 W and 170–200 mm/s, respectively). Furthermore, varying loads of Ti (1%, 3%, 5% and 15%) were mixed with TiO2, which was selectively oxidized with laser beam in the presence of oxygen environment. Findings Part defects such as cracks, pores and uneven grains growth were widely reduced in TiO2 L-PBF specimens. Increasing the laser power and decreasing the scanning speed shown significant improvements in the surface morphology of TiO2 ceramics. The amount of Ti material was fully melted and simultaneously changed into TiO2 by the application of the laser beam. The selective oxidation of Ti material also improved the melting condition, microstructure and surface quality of the specimens. Originality/value TiO2 ceramic specimens were produced through L-PBF process. Increasing the laser power and decreasing the scanning speed is an effective way to sufficiently melt the powders and reduce parts defects. Selective oxidation of Ti by a high power laser beam approach was used to improve the manufacturability of TiO2 specimens.

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