An electromechanical knocking activated device and method for working and cold-hardening the surface of tools, machine parts, etc. is disclosed. The electromechanical apparatus may include: an impact head which is secured to a support, wherein at least one part of the support is composed of a ferromagnetic material; and at least one coil which is also secured to the support. A magnetic field holds the impact head in a defined position of rest. The coil is may be positioned in the same magnetic field or a second magnetic field, through which an alternating or pulsed current may flow. As a result, the impact head is made to oscillate with a defined impact frequency, impact altitude and zero crossing. The device may be used in combination with a computer aided manufacturing system.