Cutting machine for paper material logs with a sharpening unit

A cutting machine for the transversal cutting of paper material logs, comprising:

• a structure on which are moved the logs to be cut transversely in order to obtain rolls of shorter length;
• a cutting unit arranged at a predetermined point of said structure and comprising a support plate for a blade removably connectable to a respective rotary actuator adapted to determine the rotation of the same blade about its own axis with a predetermined speed, said plate being in turn constrained to a further actuator which drags it into rotation with a predetermined angular speed about an axis parallel to the axis of rotation of the blade, the blade being arranged along a lying plane perpendicular to said rotation axis in a predetermined position within the cutting unit;
• at least one sharpening unit with two grinding wheels suitably arranged to sharpen the blade on opposite sides with respect to said plane and provided with an abrasive side;
• a device for positioning said grinding wheels with respect to the blade arranged on each sharpening unit, by means of which each grinding wheel is placed in a position of contact with the blade in a sharpening step of the latter starting from an initial inoperative position;
• wherein said positioning device is provided with automatic means for detecting the wear of the abrasive side of the grinding wheels.