Advanced Distortion Analysis of Heat Treated Rings*

The basic approach to interpret distortion as a system property is accepted in science and industry. The determination of significant factors and interactions on distortion in the overall production process of selected components represents a central point to identify relevant distortion mechanisms. In this context, a component specific distortion description is a major step to answer distortion problems. In the field of ball bearing engineering, roundness deviation of raceways is an important characteristic. But this parameter is not useful for distortion engineering because no information concerning ring shape is given. But in literature, roundness deviation can be separated in its respective forms like oval and triangle shape with harmonic analysis. In addition, this analysis can be used to specify an amplitude and a direction in the different shapes to describe distortion. In this article, harmonic analysis is used for advanced distortion analysis of tapered roller bearing. An analysis in graphical form is introduced, which illustrates both the amount and the direction of distortion.

Research on Chrome Plating Quality of the Internal Surfaces in the Hydraulic Drives with Hydrostatic Guideways

The article presents a study of the characteristics of experimental samples with a chrome coating: the straightness and ovality of the inner surface of the cylinder, as well as the hardness and thickness of the chrome coating. The chrome coating is obtained on a previously developed installation for applying chrome coating on the inner surfaces of hydraulic cylinders of hydraulic drives with hydrostatic guides. The measurement of the geometric characteristics of the internal surface of the samples was carried out, the values ​​of deviations from roundness and deviations from straightness were obtained. A study of the chrome coating was carried out, for this we cut out sectors from the samples, carried out their sample preparation, measured the hardness and took pictures under a microscope, measured the hardness and thickness of the chrome coating. The obtained measurement results: deviation from roundness, deviation from straightness, coating hardness, coating thickness - correspond to the specified technical requirements, the proposed construction of the installation for applying chrome coating to the inner surfaces and the electrolyte composition, selected earlier, are applicable for chrome plating of the inner surfaces.

Experimental study on lapping ceramic balls with variable-radius groove plate

The method of lapping precision ball with variable-radius groove is developed in recent years. An experimental study on lapping ceramic balls with variable-radius groove was carried out. Taguchi method was used to design the orthogonal experiment of rough lapping, and the material removal rate ( MRR) and the roundness were selected as evaluation indicators. The signal to noise ratio (S/N) and the analysis of variance were used to analyze experimental results. The optimal parameters combination with load pressure of 2.5 N/Ball, abrasive concentration of 10 wt% and rotation speed of 15 rpm was obtained. During rough lapping, the maximum reduction rate of average roundness is 50%, the maximum reduction rate of roundness deviation is 81%, the MRR is 16.9 μm/h, and the reduction rate of variation of ball lot diameter ( VDWL) is 90%. After semi-lapping and polishing, the best surface roughness is up to 10 nm, the best roundness is 0.128 μm, and the VDWL is 0.24 μm. The surface roughness and VDWL of the five balls tested all meet the requirements of ceramic ball with G5 grade, and the roundness value is close to the requirement of G5. The variable-radius groove lapping method is very suitable for improving the precision of batch lapping for ceramic balls.

Characterization of IN 625 recycled metal powder used for selective laser melting

Additive manufacturing of high-quality materials by Selective Laser Melting depends not only on establishing appropriate process parameters, but also on the characteristics of the metal powders used and their stability over time or after recycling. The aim of the research was to characterize the IN 625 powder used over multiple manufacturing cycles with a Lasertec 30 SLM machine. In order to achieve the research's goal, virgin and recirculated powder's physical and technological characteristics were investigated. A decrease in all D-values (D10, D50, D90) of the powder size distribution was observed after multiple recirculation cycles showing a decrease of the powder dimensional range over time. Both virgin and recirculated powders are composed of mainly spherical particles, but elongated particles and satellite particles were observed as well. The dimensional evolution analysis showed a deviation from the powder ideal roundness, deviation that is more pronounced over multiple recirculation cycles. It was experimentally determined that the powders present a good flowability based on the flow rate value obtained for both virgin and recirculated powders, confirmed also by the Hausner ratio and angle of repose.

Measurement of Maximum Deviation from Roundness Based on the Inverse Kinematics Principle

The article deals with a special method of measuring the maximum deviation of objects from roundness based on the inverse kinematics principle. The inverse measurement mechanism is based on the immobility of the measuring probes and the object performing all the motions required to measure a dimension. The advantage of this principle is minimization of the temperature change, while the adverse effect in the measurement system is greatly reduced at the same time. The measurement methodology requires a special software evaluation of the data measured. The aim of the given measurement methodology was to establish the maximum roundness deviation that corresponds to the Least Squares Circle (LSC) method. An experiment with three measuring probes was conducted to verify the methodology.

Making roundness measurement applications and control systems on the Roundness Tester Machine

Dial indicator is a comparison device usually used in industrial activities, especially in production. To make measurements at this time must be supported by technology that can facilitate operators when using it and when analyzing measurement results. Involving the programme and microcontroller are a solution to developing in roundness measurement, and then the results can be more accurate or thorough between the readable values read from the measuring instrument with the actual value of varying the amount of data. Roundness application is a program that can input measurement data automatically and can do calculations directly. Then, it can display a reference circle, a table that calculates the values of X, Y, R, X’, Y’, R’, Roundness Deviation, Run out Concentricity or a shift in the center point and also the center point shift or Theta. In measuring roundness, the test object is used the Standard Mandrel which has been certified by PT. Global Quality Indonesia, by determining three points or positions, namely in the first position the amount of data is 180, in the second position the amount of data is 90 and in the third position, the amount of data is 60 with a rotating speed of 15 mm/s. The results of the reference circle can be seen in each calculation in each position, in the second position the roundness deviation values are approaching of the Mandrel.

Influence of roundness deviation value on bearing vibration level

This article investigates the influence of roundness value on vibration level generated by bearing. One of the shape errors playing a key role in bearing’s operation is roundness deviation. Its value directly influence on vibration level generated by bearing. In the paper, the significance and methodology of roundness measurements in reference to profile of rolling surface received in technological process. Experiment consisted of inner rings matching of bearing 6009C3 with variable roundness deviation with outer rings characterized with little variability of mentioned deviation. In the next step bearing vibration level was examined. In the end, obtained results were combined with values of roundness deviation and basing on them, models of linear regression were obtained, also Pearson’s correlation coefficients were calculated.

Measuring the roundness deviation in the Vblock measurement method

In this paper the measurement capabilities of form deviation of cylindrical surfaces using V-Block method are studied. The paper presents the influence of the V - Block angle to the ratio coefficient of dimension, and the ratio coefficient of form deviation on the k-harmonic. The equations for the dimension ratio coefficient and the form ratio coefficient of kharmonic are obtained. These equations give the opportunity to choose the most appropriate combination for the V-block angle and the measurement direction, angle β. Studies have been made using V-Blocks with the most common angles by symmetrical and non-symmetrical measurement schemes. Using V-Blocks for measurement is rational and appropriate in cases where for all measured details the number of harmonics are known in advance.

Cooperation of axisymmetric connection elements under dynamic load

The article presents a method for determining the parameters that define the cooperation of the elements in the axisymmetic connection. The connection, which constitutes a shaft cooperating with a sleeve, has been tested for reaction forces in the connection during shaft rotation in the static sleeve. The shaft was characterized by deliberately modelled roundness deviations in the form of ovality, triangularity and quadrangularity. In addition, the research programme has taken into account the determination of the impact of tolerance of the outside diameter of the shaft. Determination of reaction forces has been carried out using the FEM software. The shaft has been modelled as a rigid element that rotates with a given rotational speed in the deformable sleeve. The conclusions present the impact of roundness deviation types and the tolerance value on reaction forces in the connection restraint. The method presented in the article can be used to predict the behaviour of the elements of axisymmetic connections under dynamic load, which can contribute to forecasting the durability of the connection.