Additive Medical Polymer Dimensional Verification Using X-Ray Tomography
Micro-CT verification of additive medical polymers requires physical pre-filtering, local adaptive thresholding, and ISO 15530-3 uncertainty budgeting.
Volumetric Voxel Resolution
Meaning
Metric values that define the physical size of individual three-dimensional pixels in a reconstructed tomographic image determine the level of detail of a scan. In computed tomography, volumetric voxel resolution determines the limit of defect detection and the accuracy of dimensional measurements. This value depends on the position of the sample relative to the x-ray source.
Resolution Limits
Physical limits of the detector and the magnification factor determine the voxel size. A smaller voxel size allows for the detection of tiny internal voids. In contrast, a larger voxel size reduces file sizes but can blur the boundaries of small features.
Image Acquisition
Operators must adjust the distance between the source, the sample and the detector to achieve the desired voxel density. This adjustment requires mechanical precision to avoid collision between the rotating sample and the x-ray tube. Speeding up the acquisition process without optimizing these positions can lead to blurry images and lost metrological traceability.
Inspection Impact
Selecting the correct voxel density ensures that the quality control team can identify non-conforming parts before they are shipped to customers. If a factory runs high-speed scans with inadequate resolution, critical internal flaws like micro-porosity will go undetected, which can lead to premature component failure in the field, trigger expensive product liability claims and damage the company’s brand.