Automating Crack Detection in Ceramic Roof Tiles

The Challenge

In many roof-tile factories, quality control still comes down to a person tapping each tile and listening. Auscultation by ear is slow, tiring, and inconsistent: operators fatigue, judgements vary from one person to the next, and a meaningful share of cracked tiles slips through while sound ones get rejected. On a high-throughput line that variability is expensive, in both scrap and escaped defects. The tiles make it harder still, with complex geometries (valleys, lugs, grooves), an engobe surface layer, and part-to-part variation in mass, thickness and temperature that all shift the acoustic response.

The Approach

GrindoSonic assessed whether an automated impulse-excitation system, built around the MK7, could do the listening objectively, both on the bench and on a moving line. Following ASTM E1876 and E2534, the method taps each tile, records its ring, and reads the two things that carry integrity: the resonant frequencies and the damping. A cracked tile rings differently, and its vibration dies away faster. The campaign used real production tiles in three states, sound, lightly fissured, and severely cracked, to build the decision rule. The outcome is a practical protocol: pick the vibration modes that best separate the states, fix a repeatable support and impact point, and set robust OK/NOK thresholds a machine can apply without an operator in the loop.

The Results

The acoustic signature reliably distinguished the integrity states, telling sound tiles from fissured and cracked ones, on complex geometries and under the mass, thickness, engobe and temperature variation of a real line. That turns a subjective, fatiguing manual step into a repeatable, traceable measurement suited to automated high-throughput inspection. It cuts the site’s dependence on human auscultation and gives quality control a recorded value for every tile rather than one operator’s judgement.