Surface roughness of zipper poly bag fastener rails
Micron-area shape measurement using a laser microscope
Zipper poly bag
Application
Poly bags are widely used in our daily lives. Poly bags with zippers are very convenient because they are easy to seal and also economical because they can be resealed as many times as needed. The material the bags are made of differs widely depending on what is going to be stored inside the bag, but polyethylene and polypropylene are typical bag materials. One of the important functions needed for zipper bags is a sealing ability that prevents the contents from leaking out or becoming exposed to air. Confirming the surface property of the top of the fastener rail (the area that makes contact with its counterpart when the bag is closed) is essential for helping to ensure excellent sealing performance.
The Olympus solution
Olympus' LEXT 3D laser scanning microscope is designed to make 3D shape measurements with high resolution and high precision. These features enable users to create accurate profile measurements of the roughness of a surface as well as the depth (or height) of surface irregularities. The LEXT microscope provides the same roughness (two-dimensional) parameters as contact-type microscopes do, generating measurement results that are compatible with those from contact microscopes. The LEXT microscope also provides three-dimensional roughness parameters that comply with ISO25178, enabling you to obtain more information than line roughness through surface-area evaluation using 3D images as well as numerical data. Although it would be difficult for conventional contact-type microscopes to take measurements by placing the stylus on the top of the thin rail, the LEXT microscope enables non-contact measurement at low to high magnifications without losing sight of the small area being measured.
Images of a poly bag rail at different magnifications
Objective lens 20X
Zoom 1x
Objective lens 50X
Zoom 1x
Objective lens 100X
Zoom 1x
Objective lens 100X
Zoom 3x
3D＋Profile
Before curved surface correction
After curved surface correction
Related products
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.