Meaning
Non-contact optical metrology utilizes wavelength-dispersive lenses to measure the physical surface topography of molded plastic components. The practice of chromatic confocal profiling relies on the axial chromatic aberration of a specialized lens to focus different wavelengths of light at different heights along the measurement axis. Because the sensor detects only the wavelength that is perfectly focused on the specimen surface, it generates highly accurate dimensional datasets.
This technique is applied to molded polymer micro-optics and textured automotive interiors where tactile probes might scratch or distort the delicate specimen.
Sensor Resolution
Precision calibration translates the returned light spectrum into a height measurement with sub-micron accuracy. By focusing white light through a series of lenses, the sensor splits the beam into a continuous continuum of focal points. A spectrometer then measures the peak intensity of the returned wavelength through a pinhole aperture.
This optical design allows the instrument to resolve fine surface details even on high-curvature surfaces or steep sidewalls.
Surface Evaluation
Molded parts require detailed surface inspection to ensure that micro-textures are correctly transferred from the steel tool cavity to the cooled polymer. Surface evaluation using this optical method tracks the depth of microgrooves and determines the replication percentage of the molding run. It helps process engineers adjust injection speed and hold pressures to eliminate micro-filling defects.
If the measured profile shows a rounded peak instead of the sharp ridge defined in the tooling specification, the molder must increase the mold temperature or prolong the pack phase to achieve full replication.
Cycle Efficiency
Automated quality systems deploy these optical probes to minimize inspection times during high-volume production. Continuous inline scanning reduces the necessity for slow, manual lab measurements and permits rapid qualification of multi-cavity injection molds. This prevents the shipment of out-of-specification batches and increases total plant yield.
