Application Notes
Evaluation of Oil Grooves on the Sides of Pistons
Piston
Application
Pistons move inside an engine’s cylinders to generate the power needed to drive an automobile. For pistons to move smoothly, their side surfaces (piston skirts) need to be adequately lubricated.
Grooves on the pistons’ side surfaces help maintain a layer of lubricant. It is important that the oil grooves meet precise required specifications. Oil groove configuration must, therefore, be measured with high precision to help ensure the adequate sliding performance of components. Because pistons are cylindrical, specialized fixtures are needed to hold them on a microscope for observation of the side surfaces. These fixtures increase the overall height of objects on the observation stage of a microscope, which can potentially obstruct the movement of the objective lens above them.
Solution
The LEXT OLS5000 microscope uses lasers to perform 3D measurement of samples that are up to 210 mm high. This enables measurement of the sides of pistons that are mounted on fixtures.
LEXT OLS5000 product features
- This model is capable of observing and measuring samples up to 210 mm in height.
- Measurement performance is enhanced to four times the speed of the previous model.
- Improved resolution (plane resolution of 0.12 μm) enables high-precision measurement.
- Smart scan functionality enables the acquisition of high-precision data with a press of the start button, helping minimize differences in the data acquired by different microscope operators.
Images
Piston external view
Oil groove image provided by a laser microscope
(objective lens: 20X; zoom: 1x)
Piston mounted on a LEXT microscope
Shape measurement
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.