• Title/Summary/Keyword: laser measurement

Search Result 2,037, Processing Time 0.032 seconds

Influence of Cutting Pressure on Laser Cut Quality (Relationship between Cutting Pressure and Cut Quality) (레이저 절단품질에 미치는 절단압력의 영향(2) (절단압력과 절단품질간의 상관관계))

  • Yang, Yeong-Su;Na, Seok-Ju;Kim, Won-Bae;Kim, Tae-Gyun
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.5 no.1
    • /
    • pp.63-70
    • /
    • 1988

  • Laser cutting system uses a gas jet to remove the molten or varpozed material from the workpiece. The quality of the laser cut can be strongly influenced by the gas flow charac- teristics formed through the nozzle. Laser cutting experiments were carried out for SS41 and SUS 304 to investigate the relationship between cut quality and cutting pressure. The cutting speed, nozzle pressure and nozzle to workpiece distance were also considered. The cut specimens were inspected by various manners such as dross observation, surface roughness test and kerf width measurement. Based on the data of pressure measurement on workpiece and the results of cut surface inspection, the influence of the considered cutting conditions on cut quality could be evaluated. The results of this study will be valuable in planning the optimal laser cutting process and in designing the laser cutting nozzle.

  • PDF

Optimizing Laser Scanner Selection and Installation through 3D Simulation-Based Planning - Focusing on Displacement Measurements of Retaining Wall Structures in Small-scale Buildings -

  • Lee, Gil-yong;Kim, Jun-Sang;Yoou, Geon hee;Kim, Young Suk
    • Korean Journal of Construction Engineering and Management
    • /
    • v.25 no.3
    • /
    • pp.68-82
    • /
    • 2024

  • The planning stage of laser scanning is crucial for acquiring high-quality 3D source data. It involves assessing the target space's environment and formulating an effective measurement strategy. However, existing practices often overlook on-site conditions, with decisions on scanner deployment and scanning locations relying heavily on the operators' experience. This approach has resulted in frequent modifications to scanning locations and diminished 3D data quality. Previous research has explored the selection of optimal scanner locations and conducted preliminary reviews through simulation, but these methods have significant drawbacks. They fail to consider scanner inaccuracies, do not support the use of multiple scanners, rely on less accurate 2D drawings, and require specialized knowledge in 3D modeling and programming. This study introduces an optimization technique for laser scanning planning using 3D simulation to address these issues. By evaluating the accuracy of scan data from various laser scanners and their positioning for scanning a retaining wall structure in a small-scale building, this method aids in refining the laser scanning plan. It enhances the decision-making process for end-users by ensuring data quality and reducing the need for plan adjustments during the planning phase.

  • https://doi.org/10.6106/KJCEM.2024.25.3.068 인용 PDF

Measurement of Grating Pitch Standards using Optical Diffractometry and Uncertainty Analysis (광 회절계를 이용한 격자 피치 표준 시편의 측정 및 불확도 해석)

  • Kim Jong-Ahn;Kim Jae-Wan;Park Byong-Chon;Kang Chu-Shik;Eom Tae-Bong
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.23 no.8 s.185
    • /
    • pp.72-79
    • /
    • 2006

  • We measured grating pitch standards using optical diffractometry and analyzed measurement uncertainty. Grating pitch standards have been used widely as a magnification standard for a scanning electron microscope (SEM) and a scanning probe microscope (SPM). Thus, to establish the meter-traceability in nano-metrology using SPM and SEM, it is important to certify grating pitch standards accurately. The optical diffractometer consists of two laser sources, argon ion laser (488 nm) and He-Cd laser (325 nm), optics to make an incident beam, a precision rotary table and a quadrant photo-diode to detect the position of diffraction beam. The precision rotary table incorporates a calibrated angle encoder, enabling the precise and accurate measurement of diffraction angle. Applying the measured diffraction angle to the grating equation, the mean pitch of grating specimen can be obtained very accurately. The pitch and orthogonality of two-dimensional grating pitch standards were measured, and the measurement uncertainty was analyzed according to the Guide to the Expression of Uncertainty in Measurement. The expanded uncertainties (k = 2) in pitch measurement were less than 0.015 nm and 0.03 nm for the specimen with the nominal pitch of 300 nm and 1000 nm. In the case of orthogonality measurement, the expanded uncertainties were less than $0.006^{\circ}$. In the pitch measurement, the main uncertainty source was the variation of measured pitch values according to the diffraction order. The measurement results show that the optical diffractometry can be used as an effective calibration tool for grating pitch standards.

  • PDF KSCI