The presence of manufacturing defects in a piston can have very serious consequences if these lead to a seizure of the engine on which it will be mounted. In a new engine, the seizure leads to locking in a more evident way than in an old one. The lock may result in an imbalance of the crankshaft, damage of bearings ecc., but generally it results only in the ruin of the piston skirt, and, in severe cases, in the formation of scratches on the cylinder . Today special machines, specifically designed, are able to perform complex processing for shaping of the heads and finishing of the mantle of the pistons with smaller and smaller tolerances, a few thousandths of a millimeter. The definition of appropriate control plans for each product and the careful analysis of possible defects, with the elimination of the causes, are the best guarantee of absolute conformity of output . Of particular importance is the dimensional control of the diameter of the coat and gorges.
MAGYC has realized, for this kind of check, a solution for large series production, based on an optical control desk installed directly in line with a servo robot. The profile examination of the piece is performed by a collimated optical system; the piece, backlit, is subjected to full rotation and examined on all the height of compression.