Nondestructive Computed Tomography Volumetric Void Acceptance Criteria for Heavy Polymer Sections
Computed tomography volumetric void acceptance requires zoning heavy polymer walls by stress field, setting pore limits below 0.1% in tensile skins.
Scatter Filtration
Meaning
Physical X-ray beam conditioning using metallic attenuation plates measures radiation spectrum hardness directly against unfiltered polyenergetic X-ray emissions. System setup incorporating scatter filtration places thin copper, aluminum, or brass plates between the X-ray tube and the target specimen to remove soft radiation. The hardware governs beam energy spectrum pre-hardening, scatter-to-primary radiation ratios, and grey-value boundary consistency across dense components.
Its physical action stops at pre-specimen hardware beam filtering, applying no direct correction to post-reconstruction software algorithms or detector electronic noise.
Beam Hardening Filter
Thin metal plates positioned in the X-ray beam path absorb low-energy photons that contribute to scatter without aiding material penetration. Utilizing scatter filtration improves image signal linearity when scanning dense glass-reinforced thermoplastic assemblies.
Spectral Boundary
Unfiltered polyenergetic X-ray beams passing through thick polymer components suffer soft-photon absorption, causing specimen edges to appear denser than core centers. Implementing scatter filtration pre-hardens the beam energy spectrum, dramatically reducing edge cupping artifacts and improving CT density calibration. Matching filter material and thickness to part composition and density is necessary to balance scatter reduction against overall X-ray intensity loss.
Insufficient filtration leaves secondary scatter radiation that degrades edge sharpness and introduces false void boundaries into scan data.
Image Clarity
Unfiltered scatter radiation creates fogging on detector pixels, obscuring subtle density shifts between virgin polymer matrices and reinforcing fillers. Optimizing scatter filtration setups sharpens grey-value contrast and supports accurate void volume calculations.