Meaning
Non-contact metrology characterizes physical dimensions by analyzing light interaction with a surface. Optical measurement tools capture spatial data through refraction, diffraction or shadows to determine distance, shape or surface roughness. Sensors convert light wavelengths into electrical signals, allowing software to calculate precise geometry without applying mechanical pressure that might deform soft polymers.
This process provides high resolution data suitable for inspecting delicate components where contact probes would introduce bias.
Moulding Control
Automated gauging systems verify cavity geometry after tool ejection to ensure wall thickness remains consistent with design specifications. Polymer parts suffer from differential shrinkage as cooling rates vary across complex geometries, which optical measurement detects during the initial production cycle. Moulders adjust holding time or melt temperature when data shows consistent deviation from the master file.
Accurate feedback loops prevent thousands of units from falling outside tolerance ranges due to thermal drift or moisture content changes in the feed material.
Process Resolution
Diffraction limits define the minimum feature size a scanner perceives, as light waves cannot resolve shapes smaller than their own frequency. Engineers choose hardware based on the scale of the object under test, balancing the field of view against the required micron level accuracy. Systems operate by projecting laser stripes or patterns onto the part, where distortion in the captured image reveals the topographic surface contour.
Greater sensitivity requires stable mounting, because vibration during acquisition degrades the resulting spatial point cloud.
Systemic Alignment
Precision calibration relies on reference artifacts possessing known dimensional values traceable to standardized national units. Variations occur when ambient conditions alter refractive indexes or introduce thermal expansion in the test equipment itself. Reliable results demand that measurements occur within controlled environments to minimize noise in the light path.
High frequency sampling ensures that geometric patterns emerge from background interference, validating the stability of automated manufacturing lines.
