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Background: The use of polymer bearings in some industries has increased in recent years because of their advantages, such as resistance to dirt and dust, no need for maintenance and lubrication, and chemical resistance, especially in hygienic areas. Additive manufacturing (AD) or 3D printing is also a popular method that makes complex geometric shapes easily produced using polymer material, layer by layer, of the defined component. Purpose: The study aims to investigate the applicability of producing polymer ball bearing with additive manufacturing techniques by experimentally observing the bearing's vibrations, temperature, and rolling resistance. Methods: A set of ball-bearing races—inner and outer—are produced with the stereolithography (SLA) method using polymeric resin and tested under a certain load. Results: Vibrations and load cell data for rolling resistance are analyzed through its lifetime to investigate the evolution of the bearing under the test. Conclusion: The additive manufacturing method could be preferred to produce a ball bearing with limited life. [ABSTRACT FROM AUTHOR]

Purpose: In industry applications, polymer hybrid bearings have become widespread in recent years owing to the lack of lubricant requirements, particularly in areas requiring hygiene. The additive manufacturing method gives significant advantages to have complex machinery parts, and it has become popular in the industry in recent years. However, it has some inherent disadvantages caused by layered deposition/addition of the materials, and the probability of the localized defect is much higher than in the conventional manufacturing methods. This study aims to investigate the effect of the outer race defect on the characteristics of vibration and service lifetime of hybrid polymer ball bearings produced with the stereolithography (SLA) additive manufacturing method. Design/methodology/approach: In this study, polymer bearings' races were produced with the additive manufacturing SLA method, and the outer race defect was analyzed with measured vibrations. Findings: The results show that the additive manufacturing method suggests a practical solution for producing a polymer hybrid ball bearing. On the other hand, the hybrid three-dimensional-printed bearing, which has an outer race defect, worked for approximately 8 h without any problems under a 1 kg load and a shaft speed of around 1,000 rpm. In addition, when there is a defect in the outer and/or inner race of the ball bearing, the crest factor and kurtosis of the vibration are higher than faultless ball bearing, as expected. Originality/value: This paper provides valuable information on the lifetime and vibration characteristics of polymer hybrid ball bearing produced by means of additive manufacturing. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2023-0183/ [ABSTRACT FROM AUTHOR]

Background: Regular condition monitoring of bearings has an important role in early detection of serious damages may occur on the machine. Many methods can be used to detect bearing faults, such as vibration and acoustic masurements, temperature measurements and wear analysis. Friction causes the systems temperature to rise, while the shaft-bearing system is running. Purpose: The purpose of this work, to investigate the lifetime of polymer ball bearings with regular control the vibration and temperature datas, the test rig has been designed. 6804 deep groove hybrid ball bearing consists of steel balls, polymer races has been tested. Methods: The accelerometer has been placed on the test rig for receiving and investigating vibration characteristics of the system. In addition, to determine the change of the temperature, thermocouple has been located on the test bearing housing when system working. Taken datas from the sensors have been saved on a computer with developing an algorithm environment within the experimental work. Results : Vibration results have been analyzed in time and frequency domain and associated with temperature change. The temperature-time graph and the vibration graphs which are time and frequency domain has been evaluated together. Conclusion: The results showed that accelerometer and temperature data were compatible, and temperature variation can be used to monitor bearing failure. [ABSTRACT FROM AUTHOR]

The vibrations of a shaft in rotary mechanical systems supported by angular contact ball bearings are investigated theoretically and experimentally for various preloads in this paper. In the theoretical part of the study, a dynamic bearing model is presented, a rigid shaft supported by EHL angular contact bearing has been modelled as 5 DoF. Non-linear equations of motion are solved numerically by the Runge–Kutta method. In the second part of the study, an experimental setup that enables performing different operating cases has been designed to validate the theoretical results. Theoretical and experimental data are investigated and compared in both time and frequency domains and the results are compared. It is observed from both the theoretical and experimental studies that preload has a significant effect on the vibration behaviour. Results show that the increase in preload reduces the amplitude of the variable compliance frequencies of bearing, the natural frequency of system is shifted to a higher value, and using signal processing with an envelope spectrum gives better results in spectral analysis; small deviations occur between the theoretical and the experimental data due to modulation and noise from machine elements such as gear, motor, misalignment, waviness, etc. Therefore, the presented dynamic bearing model can be used with a reasonable accuracy to examine effect of preload on the vibration of shaft-bearing system. [ABSTRACT FROM AUTHOR]

Aerostatic journal bearing applications mainly focus on high-speed precision machining, so predictable and smooth functioning of the system is crucial. Air is supplied to the bearing through a number of orifices and any unevenness in the size of these orifices will affect the performance of the system. The size difference could be due to manufacturing error and/or blockage of the orifice because of foreign materials in the air system. In this study, the performance of an aerostatic bearing with a partially blocked orifice is numerically investigated. Firstly, the airflow in the bearing clearance was modeled with Reynolds equation and this equation was numerically solved with the finite difference and differential transform hybrid method to obtain the pressure distribution. Then, the force and the stiffness are calculated from the pressure distribution for different blockage cases of the orifice and different blockage ratios. The results show that the partial blockage of the orifice significantly changes the performance of the system in a positive or a negative way according to the feeding hole position, and the blockage ratio also affects performance. [ABSTRACT FROM AUTHOR]

In this study, the pneumatic hammer instability phenomena in the aerostatic journal bearing--rotor system is analysed and discussed for different feeding hole configurations theoretically and experimentally. The influences of the configuration of the feeding holes on the nonlinear dynamics of the system are also investigated. The air flow between the surfaces is modelled with Reynold's equation and it is numerically solved with differential transform and finite difference hybrid method. Three different aerostatic bearings are modelled and simulated to investigate the ınfluences of the configuration of the holes for different angular speeds. An experimental test rig is designed and tested for different rotor speeds to validate the obtained numerical results. The dynamic response of the system is analysed using waterfall plots, bifurcation diagrams, orbit plots, phase portrait and Poincaré map, which are drawn to determine the pneumatic hammer instability region of the modelled system. The results reveal a nonlinear dynamic response of the rotor centre. In addition, the analysis shows that the feeding hole configuration affects the rotor dynamics and the pneumatic hammer instability region. [ABSTRACT FROM AUTHOR]