Overview
ISO/ASTM 52940:2025 - "Additive manufacturing of ceramics - Feedstock materials - Characterization of ceramic slurry in vat photopolymerization" defines how to characterize ceramic slurries used as feedstock in vat photopolymerization AM processes. The standard covers required composition and physical properties (solids content, dynamic viscosity, particle size distribution, chemical composition, dispersion stability), sampling and preparation of test samples, and reporting. Safety aspects are explicitly excluded.
Key topics and requirements
- Sampling & sample prep
- Samples must represent the product batch and follow agreed sampling plans; preparation per ISO 1513 and ISO 8213 where applicable.
- UV-blocked environments are recommended for handling photocurable slurries.
- Ceramics (solids) content
- Reported as mass fraction (kg/kg or wt %). If unknown, estimate by loss on ignition or thermogravimetry (ISO 11358-1, ASTM D6370, ASTM E1131).
- Dynamic viscosity (rheology)
- Measure shear-dependent viscosity (shear-thinning behavior common). Methods include cone-and-plate, coaxial-cylinder, parallel-plate rotational rheometers, Brookfield viscometers, falling-ball, and disc/ball spindles (standards such as ISO 3219-2, ISO 19613, ASTM methods listed).
- Particle size distribution
- Expressed as cumulative mass/volume (include D10, D50, D90). Use appropriate dispersion (ISO 14703/14887/14488) to break agglomerates. Test methods include laser diffraction, dynamic light scattering, image analysis, electrical sensing zone, and X‑ray monitoring (ISO/ASTM references given).
- Chemical composition
- Determine major and trace elements or impurities that affect final ceramic properties. Recommended analytical techniques: ICP–OES, ICP–MS, AAS, XRF, gravimetric/LOI methods per the relevant ISO/ASTM standards.
- Solid dispersion stability
- Assess resistance to flocculation/sedimentation over time (principles and observation methods referenced; see ISO 13097 and informative annexes).
- Test report
- Results must be documented with method references, units (SI or wt %), particle-size statistics, and any sample preparation details.
Applications & users
ISO/ASTM 52940:2025 is intended for:
- Slurry manufacturers establishing product specifications and quality control.
- Additive manufacturing service providers and OEMs verifying feedstock consistency for vat photopolymerization (DLP, SLA variants).
- Materials R&D and labs optimizing slurry formulations (solids loading, rheology, dispersion).
- Procurement and QC teams using standardized test methods in supplier agreements.
Practical uses include feedstock qualification, process optimization (layering and cure depth control), failure analysis, and improving sintered ceramic part quality.
Related standards
Keywords: ISO/ASTM 52940:2025, ceramic slurry characterization, vat photopolymerization, additive manufacturing, solids content, dynamic viscosity, particle size distribution, dispersion stability.