Use of liquid grystals for metal machining

The paper presents results of measurements of surface roughness of holes reamed in steel and cast iron workpieces, when mineral industrial oil with and without liquid crystals additives was used as coolant for reaming. Four types of twisted nematic liquid crystals (cholesterol esters) were tested: cholesterol valerate, cholesterol caproate, cholesterol stearate and cholesterol oleate. The concentration of the liquid crystals in oil was 0.5% by oil volume. The dependence of average roughness Ra of the reamed surface on coolant composition was establishe

Investigation of dissipative properties of liquid crystalline lubricant layer

This work aims to investigate vibration behavior of rotating roller - a fixed segment friction pair lubricated with pure motor oil and motor oil containing liquid crystal (cholesteryl oleate) additive. Experiments were performed under boundary friction conditions. Mechanical vibrations were registered through the processing and analysis of radial vibration data of the segment, obtained for each lubricant composition under constant roller speed. It is established that vibration level of the segment is reduced at the presence of liquid crystal additive. Theoretical investigations of load-carrying properties of individual layered liquid crystal in a lubricating gap of the film lubrication bearing show a strong increase in load as compared with the equivalent viscous lubricant

Comparable analysis of vibrodiagnostic results of rotary components with different type bearings

"Comparable vibrodiagnostic results of rotor components of technological machines with bearings of tilting-pad journal bearing, sleeve liquid-friction and of roll are given in this work. Sliding of roll of researching technological machines are described; the main characteristics of work and photo are given. Experimental comparable vibrodiagnostics measurements are done. Primary signals of measurement are gotten doing vibrodiagnostic measurements, using different programmable pockets they are transformed to other formats of data. Getting results of measurement are systematized and its analysis is done. Comparison of getting results is done and dependence of work characteristics between rotary systems with bearings of sledding friction and of roll is ascertained. Generalization of results of vibrodiagnostic researches is done and conclusions are formulated in the end of this work

Line scale Comparator Carriage vibrations during dynamic calibration

Oscillations of the comparator, which is used for the dynamic calibration of long optical line scales, are analyzed in the paper. The accuracy of determination of the position of optical lines on the scale depends on the velocity of the carriage, which transports the microscope with a CCD camera in relation to the line scale. Oscillations influence the velocity equability, its value, and at the same time the error compo measuring. The base part of the comparator is acted upon by external excitations which come through the foundation and supports, also due to natural frequencies of the comparator set. It is shown in the work that vibration surroundings acting on the comparator have a random character and correspond to the criteria of the normal (Gauss) distribution. It is proved experimentally that preaching amplitudes of measured components of vertical and horizontal oscillations influence the stability of the carriage movement which causes the error of measurin

Tribological adhesion of particles in acoustic field

This paper investigates interaction between two particles in acoustic field. It is shown that additional oscillating movements of particles occur as a result of plain acoustic wave action. This sufficiently increases the probability of collisions between particles. Micro-displacements in the collision zone help to remove various pollutants, oxidation products and adsorbed gas molecules from surfaces of particles. Strong adhesive bonds are formed in the contact area between the particles

Use of liquid grystals for metal machining

The paper presents results of measurements of surface roughness of holes reamed in steel and cast iron workpieces, when mineral industrial oil with and without liquid crystals additives was used as coolant for reaming. Four types of twisted nematic liquid crystals (cholesterol esters) were tested: cholesterol valerate, cholesterol caproate, cholesterol stearate and cholesterol oleate. The concentration of the liquid crystals in oil was 0.5% by oil volume. The dependence of average roughness Ra of the reamed surface on coolant composition was establishe

Research of positioning accuracy of robot MOTOMAN SSF2000

Research of the dynamic properties, positioning precision and repeatability of MOTOMAN SSF2000 movement is presented in this article. Dynamic properties were analyzed using a mobile equipment of measuring „Machine Diagnostic Toolbox Type 9727“ with a DELL notebook. The manipulator vibrations were measured in two robot’s positions: vertical and horizontal, and at three different speeds. The research was made under three different conditions, changing the tool mass and spee

Numerical Simulation of a Pulsating Flow Generated in an Ejector

This paper presents a numerical simulation of a pulsating flow generated inside an ejector; the flow is intended to oxidize ferrous iron (Fe2+) dissolved in drinking water to ferric iron (Fe3+). The pulsating flow ejector can be used in water treatment systems where the water is saturated with oxygen before being treated by filters. It is shown that the pulsating flow is generated due to fluctuations in the pressure, density, and velocity of the flow inside the ejector. It is established that the flow pressure inside the ejector varies from 0.513 to 0.0719 MPa, the flow density varies from 4.64 to 0.66 kg/m3, and the flow velocity varies from 0 to 590 m/s. Numerical simulation results have shown that an acoustic field is generated inside the ejector during the mixing of air with water, which accelerates the coagulation of iron particles. The obtained sound power level value of 100 dB shows that the pulsating flow ejector can be used for non-reagent water treatment

Research of positioning accuracy of robot MOTOMAN SSF2000

Research of the dynamic properties, positioning precision and repeatability of MOTOMAN SSF2000 movement is presented in this article. Dynamic properties were analyzed using a mobile equipment of measuring „Machine Diagnostic Toolbox Type 9727“ with a DELL notebook. The manipulator vibrations were measured in two robot’s positions: vertical and horizontal, and at three different speeds. The research was made under three different conditions, changing the tool mass and spee

An Investigation Into Fault Diagnosis in a Rotor-Bearing System with Dampers Used in Centrifugal Milk Separators

This paper deals with the problems encountered in the fault diagnosis in damped rotor-bearing systems used in centrifugal milk separators. It is shown that direct bearing vibration measurements are more reliable than indirect (through rotor housing) vibration measurements. However, in most cases it is not possible to measure bearing vibrations directly. The factors causing large diagnostic measurement errors, such as the influence of the vibration damping system, step-up gear and electric motor noise are discussed in the paper. It is established that vibration measurements of the damping system are noninformative and cannot be used to diagnose faults in bearings. It is proposed to use the vibration spectra correlation to predict bearing failures in rotor-bearing systems of this type