Quality Assurance of Machine Repair in Production Plants

Trzepieciński, Tomasz; Jaworski, J.

doi:10.12776/ams.v23i4.1007

Cited by 2 publications

(1 citation statement)

References 19 publications

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“…The process creates a force that causes the material to deform. Many physicochemical processes take place during forming which play a key role in the quality of the product obtained, the tooling lifetime or the accuracy of the shape of the formed product [ 1 , 2 , 3 ]. There are phenomena in the contact zone that are impacted by many variables, such as the macro- and microgeometry of the contact surfaces, pressure, processing temperature, type and viscosity of the lubrication used, die structure, topography and physicochemical phenomena of the contact surfaces, and load dynamics [ 4 , 5 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

Modeling of Friction Phenomena of Ti-6Al-4V Sheets Based on Backward Elimination Regression and Multi-Layer Artificial Neural Networks

2021

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This paper presents the application of multi-layer artificial neural networks (ANNs) and backward elimination regression for the prediction of values of the coefficient of friction (COF) of Ti-6Al-4V titanium alloy sheets. The results of the strip drawing test were used as data for the training networks. The strip drawing test was carried out under conditions of variable load and variable friction. Selected types of synthetic oils and environmentally friendly bio-degradable lubricants were used in the tests. ANN models were conducted for different network architectures and training methods: the quasi-Newton, Levenberg-Marquardt and back propagation. The values of root mean square (RMS) error and determination coefficient were adopted as evaluation criteria for ANNs. The minimum value of the RMS error for the training set (RMS = 0.0982) and the validation set (RMS = 0.1493) with the highest value of correlation coefficient (R2 = 0.91) was observed for a multi-layer network with eight neurons in the hidden layer trained using the quasi-Newton algorithm. As a result of the non-linear relationship between clamping and friction force, the value of the COF decreased with increasing load. The regression model F-value of 22.13 implies that the model with R2 = 0.6975 is significant. There is only a 0.01% chance that an F-value this large could occur due to noise.

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Section: Introductionmentioning

confidence: 99%

Modeling of Friction Phenomena of Ti-6Al-4V Sheets Based on Backward Elimination Regression and Multi-Layer Artificial Neural Networks

2021

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The Effect of Absorbed Hydrogen on the Rotors of Steel Machining Products During Powerful Turbo Aggregate Repairs

Balitskii,

Syrotyuk,

Kolesnikov

et al. 2024

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Rotor shafts are the most heavily loaded and accident-prone parts of powerful turbine generators, which are cooled using hydrogen. To eliminate damage sustained during operations, repair work was carried out, including the removal of defective parts, surfacing, and turning. This study tested the machinability of the rotor shaft using prototypes made from 38KhN3MFA steel. A section of the shaft was degraded due to prolonged operation (250 thousand hours), and compared to the central part, a decrease in the average grain size from 21.57 μm to 12.72 μm and an increase in the amount of hydrogen absorbed during operation from 2.27 to 7.54 ppm were observed. With the frequency of dry turning increasing from 200 to 315 RPM, the chips changed their form from mostly rectangular with linear dimensions of 10 to 20 mm to large spiral rings with a diameter of 15 to 20 mm and a length of more than 50 mm. Cracks of 1 to 4 mm in length were found in most chip particles at both rotational speeds. Increasing the rotational speed from 200 to 315 and up to 500 RPM led to the formation of an oxide film on the surface of the specimens, as evidenced by the appearance of oxygen during local analyses of the elemental content on the chip surface. The saturation of specimens by hydrogen gas led to the formation of finer chips compared to the non-hydrated material, and the roughness of the machined surface increased at hydrogen contents of 6 and 8 ppm. In both dry and coolant cutting operations, surface roughness reflects the degradation of the rotor shaft or experimental prototypes due to hydrogenation, which can be used to diagnose the condition of the rotor after long-term operation.

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Quality Assurance of Machine Repair in Production Plants

Cited by 2 publications

References 19 publications

Modeling of Friction Phenomena of Ti-6Al-4V Sheets Based on Backward Elimination Regression and Multi-Layer Artificial Neural Networks

Modeling of Friction Phenomena of Ti-6Al-4V Sheets Based on Backward Elimination Regression and Multi-Layer Artificial Neural Networks

The Effect of Absorbed Hydrogen on the Rotors of Steel Machining Products During Powerful Turbo Aggregate Repairs

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