Vibrations in the Production System

The ways of searching for methods of increase of efficiency of the process of machining by water jet, of shortening the time inevitable for cutting the individual components with preservation of the quality of the machined area or of reduction of vibration size have not been completed yet. Vice versa, the technology—besides the unlimited assortment of sectile material—disposes a tool without negative effect upon a workpiece or environment and has become a progressive technology in the course of the last years. The infinite or progressive technology of machining by abrasive water jet has gained an importance by adding the abrasive substances. High speed of outflowing water jet with admixture of abrasive allows intensive, economic and ecological machining of almost all industrial materials.

Grain materials represent the most frequent form of the solid occurrence, and therefor, the grain composition ranks among basic information characterizing the properties of the substances.

The sieve analysis represents the oldest, the simplest and the cheapest method of detection of particle size of solids. The method belongs to a narrow group of fractionating or of separating techniques of particle size analysis.

Any equipment vibrates. Each vibration is specific for the equipment, and vibration is changed in relation to the change of conditions under which the particular equipment operates. The noise produced by the equipment represents only partial information on the state of equipment. Vibration analysis detects a broad scale of defective states of equipment. Increased vibrations may indicate standard wear of components or they can refer to origin of the problem. At the same time, the increased vibrations may signalize a need of inevitable servicing operation. Understanding of origin of vibrations and their development represents a key information for further steps of problem solving.

The methodology of measurement contains the basic information on performance of measurement of the magnitude of acceleration of technological head vibrations of the selected technical system in the time and frequency domain without the use of abrasive fraction and with the application of narrow fraction of abrasive. The chapter is divided into several basic parts:

The files of the individual measurements of the structure mentioned in Sect. 5.​2.​1 contain the assessment of magnitudes of amplitudes of acceleration of the technological head vibrations along with the related frequency spectra under the change of abrasive mass flow, type of abrasive and of narrow fraction of abrasive grain in case of machining of abrasion-resistant steel of K 13—HARDOX 500 type.

Comparison of the individual measurements of sizes of the acceleration amplitudes of technological head vibrations rests in formation of the envelopes in comparative graphs from the graphical dependence of frequency spectra described in the previous Chap. 6 “Assessment of Measurement of Vibration Sizes”. The following structure includes the measured values:

In general, the technical condition of equipment in operation deteriorates in the course of the time. Deterioration of technical condition represents the consequence of the influence of factors with negative effect. The fundamental factors include increased stress, temperature, dust nuisance and vibrations. Monitoring of the parameters allows obtaining basic objective data inevitable for assessment of the condition of equipment or for correction of negative condition. The operative condition of equipment requires the values to range within the specified limits.

Mechanical oscillation represents the undesired factor with negative effect upon almost any equipment with its environment. A long-term effect of oscillation upon the systems of structural complexes causes shortening of the service life and increasing of noise level. Diverse literatures and standards list limit values of two parameters of vibrations, i.e. speed and acceleration of vibration amplitudes. They specify the amount by which the value of vibrations can increase in contrast to initial value yet only a few technical devices dispose of definitions of these values. By means of the configuration of theoretical knowledge and by means of performance of experiments, it was partially achieved. The formed frequency spectra and their consequent analysis define the initial state and represent a suitable basis for defining the boundary which the values of vibration sizes cannot exceed. Pursuant to description and analysis of the present state of cognition and solutions focused on operation of production system with the water jet technology, the monograph “XZ” updates current knowledge and solutions by new information in the sphere of research and the application of the sieve analysis of abrasive in relation to origin and magnitude of acceleration amplitudes of technological head vibrations.