Overview
EN 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 compositional and physical properties (for example solids content, dynamic viscosity, particle size distribution, chemical composition, and dispersion stability) and gives accepted methods for sampling and preparing slurry samples for testing. Note: safety aspects are outside the scope of this document.
Key topics and technical requirements
- Sampling and sample preparation
- Samples must be representative of the batch and prepared in accordance with agreed procedures and ISO 1513; raw powder sampling references ISO 8213.
- Recommended handling under UV-cut light to avoid premature photopolymerization.
- Ceramics content (solids loading)
- Reported as mass fraction (wt. %) or volume fraction (vol. %).
- If unknown, estimate via loss-on-ignition or thermogravimetry referencing ISO 11358-1, ASTM D6370, D7348, E1131.
- Dynamic viscosity and rheology
- Recognizes non-Newtonian behavior (shear thinning) - specify shear rate/stress used for measurement.
- Acceptable measurement devices and methods include cone-and-plate, coaxial-cylinder, double-gap, parallel-plate, Brookfield viscometers, falling-ball and spindle methods (referenced standards such as ISO 3219-2, ISO 19613, ASTM D2196/D7395/D4287).
- Particle size distribution (PSD)
- Report cumulative PSD (D10, D50, D90) as mass or volume fractions consistent with ISO 9276‑1/2.
- Emphasizes deagglomeration and appropriate solvent selection per ISO 14703 and ISO 14887.
- Solid dispersion stability
- Characterize stability and changes over time using methods and observations guided by ISO 13097 (see informative Annex C).
Practical applications and users
- Who uses it:
- Ceramic feedstock manufacturers and formulators
- Vat photopolymerization AM machine OEMs
- Quality control and test laboratories
- R&D teams and materials scientists developing ceramic AM slurries
- Purchasing/specification engineers comparing suppliers
- Practical benefits:
- Standardized acceptance testing for incoming slurry batches
- Informed slurry formulation and solids-loading optimization
- Root-cause analysis for print defects related to rheology or PSD
- Consistent reporting to support supplier–customer agreements
Related standards
- ISO/ASTM 52900 (AM vocabulary & fundamentals)
- ISO 1513, ISO 8213, ISO 11358-1, ISO 13097, ISO 14703, ISO 14887
- ISO 9276-1/2 (PSD reporting)
- Viscosity/rheology references: ISO 3219-2, ISO 19613, ISO 2555; ASTM D2196, D7395, D4287, D7175, etc.
Using EN ISO/ASTM 52940:2025 helps ensure repeatable, comparable characterization of ceramic slurry feedstock for reliable vat photopolymerization printing and supplier qualification.