Custom ceramic acceptance criteria should distinguish cosmetic variation from structural defects. Defect type, location, depth and functional consequence matter more than appearance alone, especially around seals, load paths, holes and thin sections.

Custom ceramic parts can meet length, diameter and thickness tolerance while still failing fit or sealing because of warpage, nonparallel surfaces or poor straightness. Specify geometric tolerances only where they control real function.

Visual inspection is the first crack-detection method for industrial ceramics, while penetrant, microscopy, acoustic methods, ultrasonic inspection or CT may be useful for specific dense or high-value parts. Highly porous ceramics require particular caution because many surface inspection methods produce misleading results.

Elastic modulus measures ceramic stiffness, not failure strength. High modulus improves dimensional rigidity but can increase thermal or assembly stress when movement is constrained. Joint design and support condition must therefore match the brittle, stiff nature of ceramic.

The coefficient of thermal expansion is critical for thermally cycled and constrained process ceramics. Evaluate CTE together with component size, temperature range, metal interfaces and installation clearance instead of relying only on maximum operating temperature.