Dimple t is a defect that appears as a microscopic crater on the surface of the ceramic body on which an aqueous suspension has been discharged (and that is still in the drying phase). The problem results in an imperfect application due to a lack of flatness. The depth of dimples can be very different and the criticality may concern the most superficial layer (such as glaze) or other layers previously applied, such as engobe or smaltobbio.

The problem concerns in particular engobes and glaze suspensions, especially with low weight applications (low solid content).

The causes of dimples, as well as of any other defect that concerns the ceramic body, is due to a mix of elements that can also interact with each other and therefore the list is surely very long. The most significant are:

a) Impurities within ceramic raw materials

b) Improper use of defoamers

c) Improper application parameters: too long drying times and too low density/viscosity in respect of the production line parameters

d) Contamination within the suspension