Application Notes
Shape and surface roughness measurements of screws / Surface roughness measurement using a laser microscope
Application
Screws are used to join parts by fitting tightly. A tight fit is created by static friction, and manufacturers need to ensure that the screws have enough friction to prevent them from becoming loose. The amount of static friction is proportional to the screw’s surface roughness. Consequently, manufacturers must measure surface roughness to ensure the screws conform to standards. In precision screws, the area that needs to be measured is so small that it is difficult to measure using conventional evaluation methods. In addition, to determine the friction values, the surface roughness needs to be measured instead of conventional line roughness.
Olympus' solution
Olympus' LEXT 3D laser microscope enables you to evaluate three-dimensional shapes such as the threads or grooves of a screw, the pitch or height of the threads, and the angle of the flank. The LEXT also makes it simple to measure the roughness of a precision screw’s contact surface so manufacturers can ensure quality. The microscope’s stitching function seamlessly combines multiple images into a single image for wide-field observation.
Entire 3D image of a precision screw
10X objective lens; 1x zoom; stitching
Surface roughness of the root of a thread
100X objective lens; 1x zoom
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LEXT OLS5500
Hybrid 3D Optical Profilometer
- Traceable surface measurements from the nanometer to micrometer scale
- Laser scanning microscopy (LSM), white light interferometry (WLI), and focus variation microscopy (FVM) in one award-winning platform
- First 3D optical profilometer to offer guaranteed accuracy and repeatability* for both LSM and WLI measurements
- WLI mode delivers up to 40x faster measurement throughput than conventional LSM
- Exceptional precision across surfaces with in-house engineered optics
- Intuitive interface and smart automation streamline operation for users of all levels
- AI-enhanced and high-throughput workflows with PRECiV™ software integration
*Based on Evident’s internal research as of October 2025. The guaranteed accuracy and repeatability apply only if the device has been calibrated according to the manufacturer’s specifications and is in defect free condition. Calibration must be performed by an Evident technician or an Evident-authorized specialist.
LEXT OLS5100
The LEXT™ OLS5100 laser scanning microscope combines exceptional accuracy and optical performance with smart tools that make the system easy to use. The tasks of precisely measuring shape and surface roughness at the submicron level are fast and efficient, simplifying your workflow and delivering high-quality data you can trust.