Designing Restrained State Quality Fixtures for Flexible Plastic Assemblies
Restrained state fixtures simulate final assembly fasteners with calibrated clamps on datum targets to measure flexible plastic profiles accurately.
Blue Light Scanning
Meaning
Non-contact optical metrology systems utilize narrow-band blue LED illumination to capture high-density three-dimensional coordinate data from physical objects. Industrial applications often deploy blue light scanning to verify the dimensional accuracy of injection-moulded polymer components against their original computer-aided design files. This method excels in environments with high ambient light because the blue wavelength stands apart from typical workplace lighting.
It allows rapid digitisation of complex geometries, including freeform curves and thin-walled structures, before production runs begin.
Optical Capture
Metrology processes rely on the projection of structured light patterns onto the surface of a polymer part while dual cameras record the resulting deformation of the lines. Because blue light scanning operates at a short wavelength, it filters out ambient thermal radiation and minimises the optical noise that frequently disrupts red or white light systems. High-intensity light-emitting diodes deliver structured patterns that the sensor captures in seconds.
This speed allows moulders to map entire components rather than relying on sparse point-by-point data collection.
Dimensional Control
Quality assurance workflows in precision moulding require accurate feedback to compensate for volumetric shrinkage and tool wear. Implementing blue light scanning during the first-article inspection stage helps identify warp, sink marks and other volumetric deviations caused by non-uniform cooling. When a moulder compares the scanned mesh to the nominal CAD geometry, the software generates a color-coded deviation map.
This visualization helps technicians adjust holding pressures and cooling times to bring the parts within specified tolerances.
Surface Evaluation
Molded parts with high-gloss finishes or textured surfaces demand precise replication of the tooling surface. Using blue light scanning on the initial trial parts reveals micro-surface deviations and injection defects before the tool is released for high-volume production. It ensures that the texture depth on the plastic part matches the tool design, avoiding costly reworking of the hardened steel cavity.
In addition, the method is non-destructive, meaning it does not deform flexible or soft elastomeric materials during the measurement process. Measuring the parts without physical contact prevents surface scratches and eliminates the mechanical forces that would otherwise distort the flexible polymer walls of the scanned object.
Tooling Surface Polish Impact on First Article Inspection Accuracy
Uncalibrated optical scans on mirror-polished plastic introduce up to fifteen micrometers of false elevations, ruining First Article Inspection accuracy.