Industry pain points related to hole detection:

In the field of precision manufacturing, quality control of holes—such as those found in engine cylinders, fuel injectors, hydraulic valves, and semiconductor through-holes—has always been a challenge.

1. High aspect ratio: Hole depths can exceed 10 times the diameter, making it difficult for traditional optical microscopes to focus on the bottom.

2. Confined space: Probes have difficulty accessing the interior, and contact measurements can easily damage the inner walls.

3. High precision requirements: The surface roughness, roundness, and taper of the inner walls directly affect product performance.

Technical Principles:

White-light interferometric profilometers operate on the principle of low-coherence interferometry:

The white light emitted by the device is split into two beams by a beam splitter—one illuminates the surface being measured (the measurement beam), and the other illuminates a standard reference plane (the reference beam); after reflection, the two beams recombine to form interference fringes.

Since white light has an extremely short coherence length (only a few micrometers), the clearest interference signal appears only at positions where the path difference is zero. By scanning point by point along the Z-axis, the system acquires interference signals at different heights. These signals are then reconstructed using algorithms to generate a 3D topographic map, converting the microscopic topography of the borehole wall into quantifiable data.

Solution:

Using a POMEAS 3D white-light interferometric profilometer equipped with a deep-hole measurement accessory, the three-dimensional topography of the cylinder bore at various heights is captured using scanning interferometry.

Test Results:

For more information on the application of white-light interferometric profilometers in aperture inspection, please visit the POMEAS website at www.pomeas.cn or call our service hotline at 13925702452.