Forced Vibrations in Machines

A machine that generates forced vibration and uses it to the maximum extent does not always eliminate shifter vibration or shaker vibration of the mechanical system, but it may be used for specific purposes. One type of these mechanical systems is a vibrating screen system. Vibrating screens are used when there are different sizes of the same material to be separated (grain crushing, aggregate crushing for construction purposes, coal production, etc.). A particular item is placed on the screen (at the top of the system) and looks like a mesh with holes.

What happens when the machine is "pushed" with repetitive force? As the repetitive force vibrates the machine at a natural speed, the machine vibrates more and more strongly. In addition to vibrating at the "wanted" speed, the machine vibrates excessively because it is receiving external support. Machines that vibrate like this are said to resonate

Vibration is not always a problem. Vibration is essential for certain tasks. Machines such as vibration polishing machines and vibration drums use vibration to remove materials and surfaces. The vibration feeder uses vibration to move the material. In buildings, concrete is compacted in shape and compact filler using vibration machine. Vibration rollers help to compress asphalt used in highway paving. In other cases, vibration is specific to mechanical design. For example, there are virtually unavoidable vibrations in the operation of reciprocating pumps and compressors, internal combustion engines and gearing. For well-designed, well-maintained machines, this vibration should not deserve attention.

There are two main technologies for vibration drilling: autonomous vibration system and forced vibration system. Most vibration drilling technology is still at the research stage. In the case of a self-retaining vibratory borehole, it uses the natural frequency of the tool to naturally vibrate during cutting and its vibrations are self-sustained by the mass spring system contained in the tool holder. Other studies use piezoelectric systems to generate and control vibrations. These systems allow for high vibration frequencies (up to 2 kHz) and small amplitudes (a few microns); they are particularly suitable for small hole drilling. Finally, the vibration can be generated by a mechanical system, the frequency given by the combination of rotation speed and frequency per revolution (1 oscillation per revolution) and the amplitude is about 0.1 mm.