Improper Lubrication Research Articles

ANALISA KERUSAKAN CONNECTING ROD PADA MESIN DIESEL KENDARAAN BERMOTOR

Connecting rod and crank pin bearing are important components of automotive diesel engine. If these components failed, all of engine system would be shut down. In this research, these components failed during operation. Detail analysis of the failed surface showed that the failure in connecting rod and crank pin bearing was caused by improper lubrication system. Evidence of improper lubrication system was proved by the existence of black scratch and chipping on crank pin bearing which formed by high friction during operation. High friction affects performance of other pistons and therefore bolts of connecting rod experienced dynamic tension load. With repeated load during operation, crack initiated on the bolts and propagated until the bolt could not withstand the load anymore before they are finally broken.

Lubrication Mode and Selection of the Helicopter Transmission System Roller Bearing

The bearings will directly affect the performance of helicopter transmission system whether they are in normal work or not. Lubrication is the essential element for the normal work of bearings. Under the condition of the bearing design and manufacture technique, material technique is becoming more and more advanced, and lubricant becomes “the fifth main part”, which has been got a wide-ranged agreement. One of the most critical factors to improve bearing life is lubricant. This paper analyzes lubrication type and mode, and the failure of helicopter transmission system roller bearing caused by improper lubrication. It further explains the importance of lubrication to the bearings. And how to select lubrication mode and lubricant to improve the bearing life is also summed up.

Tribological behaviour of DLC coatings for sheet metal forming tools

Abstract Sheet metal forming processes usually involve a sliding contact between the blank and tool surfaces, thus requiring the use of lubricants to prevent severe tribological conditions at the tool–workpiece interface. However, improper lubrication policies may have a negative impact on the environment, due to the use of unhealthy degreasing agents to wash the formed parts. In recent years, the introduction of the diamond like carbon (DLC) coatings has represented an attractive solution for the development of dry or nearly-dry forming processes. To be effective, these coatings must strongly bond to the dies substrate in order to grant resistance to the abrasive and adhesive wear. Although many approaches for evaluating the tribological performances of such coatings can be found in the existing literature, they often suffer from limitations in reproducing the interface conditions typical of the industrial processes. The objective of the present research work is to investigate the tribological behaviour of DLC coatings applied to sheet-forming tools under process conditions compared to the ones experienced by the traditional coatings used in industry. Experimental values of the friction coefficient have been determined by means of strip drawing tests and the coatings wear and adhesion to the substrate have been investigated by means of pin-on-disk and scratch tests.

Detection of lubrication starved bearings in electrical motors by means of vibration analysis

The detection of improperly lubricated bearings from vibration patterns is a difficult task especially when records from short operating periods are available. This is exactly the case of end-quality assessment systems. This problem has been addressed by applying both cyclostationary analysis and spectral kurtosis for the selection of a frequency band in which variations in vibration patterns are most expressed. The approach was evaluated on a test-set comprising 63 electrical motors with fault-free and 21 with improperly lubricated bearings. The results reveal that improper lubrication is expressed as increase in the spectral components at bearing cage and ball spin frequency.

Fatigue failure of steel links operating as chain components in a heavy duty draw bench

Steel links used as chain elements in draw benches are subjected to repetitive tensile stressing due to successive loading and un-loading conditions. In addition, friction caused by poor or improper lubrication can be very harmful, due to associated surface degradation and wear/corrosion related processes which play an important role to the integrity and performance of the machine components. Frequent in-service failures of chain links occurred in a copper tube draw bench have led to increased maintenance costs and machine downtime resulting in poor productivity indicators. Samples from fractured components, made of induction hardened structural steel, were brought for a failure analysis investigation. Failure analysis findings suggest strongly that the failure was accomplished by the operation of fatigue mechanism initiated at the inner-eye area of the link and followed by brittle overload fracture. Review of the service history (operating conditions, applied loads), in combination to the examination of a potential substitution of the material to a more fatigue resistant one are recommended as further fatigue damage preventive actions.

Suppression of Macroscopic Defects through the Control of Friction between Workpiece and Dies in a Forged Magnesium Alloy Part with Ribs

Superplastic magnesium alloy sheets were closed-die forged into an experimental part with ribs, which are asymmetrical elements to the plane of the forging. A macroscopic surface defect, which was formed by extrusion-type flow, was observed opposite to the rib during forging under improper lubrication conditions. However, the formation of the defect could be successfully suppressed by changing the frictional conditions of the workpiece/dies interface. Analysis of the rib forging using a finite controlled volume method simulation suggested that the suppression of the extrusion-type defect is associated with a change in velocity field distribution of the deforming material. [doi:10.2320/matertrans.MC200740]

Importance of early detection of maintenance problems in rotating machines in management of plants: Case studies from wire and tyre plants

In this article, importance of application of predictive maintenance concept with vibration measurement has been discussed. Appreciation of the subject was performed with the help of data collected cases related to maintenance problems from Plants A and B. The first case was examined in aerial conductor manufacturing Plant A. The company does not apply predictive maintenance (PM) in management of the manufacturing activities. The machines used in conductor and similar wire processing plants have very big rotors and their loads on rotors continuously change. Therefore, these types of machines are good examples in checking the health of the machine regularly. The second case was analysed in vehicle tyre plant named as Plant B and it has perfect usage ability of vibration technique of PM methods. The importance of the regular collection of vibration signatures in evaluation of conditions of rotating machines has been analysed in details to indicate the power of the predictive maintenance technique in prevention of losses, which are caused by unbalanced forces, misalignments, improper lubrication of ball bearings, metal fatigue and cracks occurred in welding of constructed parts and locking of the ball bearings due to excessive heating. The second case observed in Plant B is an example to show detection of a ball bearing failure just in time. Evaluation of second case has been performed using measurements of vibration signatures of the machines with the help of fault indicator graphics. Results from the cases have been summarised to give useful ideas in management of the plants to the persons responsible with production and maintenance subjects.

Surface roughness evolutions in sliding wear process

Wear debris analysis is a technique for machine condition monitoring and fault diagnosis. One key issue that affects the application of wear debris analysis for machine condition monitoring is whether the morphology of the wear particles accurately depicts their original states and the surface morphology of the components from which the particles separate. This study aimed to investigate the evolution of the surface morphology of wear debris in relation to change in the surface morphology of wear components in sliding wear process. Sliding wear tests were conducted using a ball-on-disc tester under proper lubrication and improper lubrication conditions. The study of the particle size distribution and the surfaces of both the wear debris and the tested samples in relation to the wear condition and the wear rates of the wear components were carried out in this study. The evolutions of the surface topographies of both the wear debris and the wear components as wear progressed were investigated. This study has provided insight to the progress of material degradation through the study of wear debris. The results of this research have clearly demonstrated that: (a) there is a good correlation of the surface morphology of wear debris and that of the wear components, and (b) the surface morphology of wear debris contains valuable information for machine condition monitoring.

Wear characterization by fractal mathematics for quality improvement of machine

PurposeThe objective of the present work is to find an alternative approach for gearbox condition monitoring using wear particle characterization incorporated with image vision systems.Design/methodology/approachIt is a quite well‐known phenomenon that wear generates whenever two metallic bodies have contact with each; other hence the present work tries to investigate the effect of improper lubrication in the gearbox due to wear particle generation between gear wheels. Since the identification of wear for machine condition monitoring needs much expertise knowledge and is time‐consuming using the conventional process, fractal mathematics with image morphological analysis has been utilized to overcome this situation in the present work.FindingsThe type of wear has been found for the present method by utilizing the lubricant used in the system ferrographically and a great deal of image processing has been done to characterize the type of particle so that the proper maintenance strategy can be undertaken.Originality/valueWear particle characterization is a quite common method in maintenance engineering, especially when fault diagnosis of any equipment is concerned. In the present work, the CCD acquisition of the images has been done for different particles, but one analysis amongst them has been shown in this paper. Among all other methodologies, the new technique of fractal mathematics has been used in the present work to minimize the imaging hazards and to make the system more user‐friendly.

Assessment of useful life of lubricants using artificial neural network

Most catastrophic failures of machines result from improper lubrication. The cost of lubricants can be up to 10‐12 percent of the production cost an essential part of maintenance management, therefore it is essential that the optimization of lubricants is at the optimum. This paper decribes and considers present practice in lubricant condition monitoring.

Acoustic Analysis of Quiet Ball Bearing Failure Modes

Qualitative analysis of rotating machinery structureborne noise and vibration can identity ball bearing installation problems. Indications of improper lubrication and impending bearing failures are identified. The problem of nonuniform motion of ball bearing components in determining expected bearing frequencies is noted together with the effects of grease deterioration. The philosophy of structureborne noise versus vibration measurements and an appreciation of several analysis techniques in the context of determining maintenance requirements and evaluating subsequent repair are discussed.