Paweł Pieśko

SURFACE ROUGHNESS OF THIN-WALLED COMPONENTS MADE OF ALUMINIUM ALLOY EN AW-2024 FOLLOWING DIFFERENT MILLING STRATEGIES

The paper presents an analysis of surface roughness following milling of thin-walled components made of aluminium alloy EN AW-2024, taking into account the three different machining strategies and rolling direction of semi-finished product in the form of a plate combined with the milling feed. The aims of the study were to compare the results of machining using various technologies and show the best of them, providing the smallest roughness of the component following milling, as well as to determine the impact of rolling direction of the plate on the quality of the end surface. Measurement results of surface roughness parameters were provided information about the progress of the machining process.

A Comparative Analysis of the Impact of CNC Miller Programming on Machining Effects

Abstract This paper presents a comparison of the impact of the programming methods of a CNC miller on the machining effects. As a part of the study, the test samples were made of the EN AW-2024 aluminium alloy. The CNC machining programs compared were developed with two programming methods: by inputting the CNC machining program directly from the CNC millers control panel (machine level programming) and in a CAM software environment (CAM programming). The machining effect indicators adopted included: machining time, surface quality, and dimensional deviation of specific geometrical features. A measurement of the machining times revealed than the CAM programming reduced the machining time up to 20% from the machining time of the machine level programming. A conclusion stands valid that CNC machining programs developed in the CAM software environment are more efficient than CNC programming directly with the CNC miller control panel, most likely due to the machining path optimisation in CAM. In addition, given the experimental test results, it was found that smaller machined errors were also obtained for CAM programming. To conclude, the comparative analysis revealed that CAM programming provided better machining results than the machine level programming.

Carbide Milling Cutter Blades Durability during Machining of AL-SI Casting Alloy

Abstract The paper presents results of wear measurements of carbide shank milling cutters during machining of AlSi10Mg casting alloy. The comparison was made between blades wear of milling cutters without protective coating, with TiB2 coating, and with TiAlCN coating. All cutters had identical geometry dedicated to milling of materials of ISO N group. To assess blades wear degree, measurement of two direct indicators, i.e. VBC and VBBmax, and one indirect indicator, i.e. machined surfaces roughness, were used. Received results allowed to determine usefulness of using selected protective coatings in machining of aluminium alloys, especially Al-Si casting alloys.

Influence of included drill angle on cutting forces during drilling of aluminum alloy

The paper presents the analysis of the influence of the twist drill geometry, in particular the 2κr angle, on the cutting forces during holes drilling in the element made of aluminum alloy for plastic forming EN AW-2024. In addition, the impact of the application of the drill geometry correction on the values of cutting forces was also investigated. During the tests, the values of components Fx, Fy and Fz of the cutting force for tools with different geometry with the set, variable technological parameters, i.e.: feed f and cutting speed vc were measured. The changes in the value of the axial component Fz were analyzed in detail. It was found that the use of drills with an angle of 2 κr < 100°, due to the significant value of the axial force Fz and high amplitude is unfavorable. Also, the lack of drill correction translates into an increase in the value of the axial force Fz and its amplitude.

The influence of changing the parameters of water-abrasive cutting on the quality of cutting composite cross-section structures

Presented are results of the surface quality sandwich composites (aluminum alloy EN AW-2024 and CFRP) by using an abrasive water-jet. The experiments were conducted with different speed of cutting, pressure of the abrasive water, mass flow rates, entry side of the stream and quantity of composite layers. The analysis has been studied based on received bevel angle values.

State of Residual Stresses After the Process of Milling Selected Aluminium Alloys

The purpose of this paper was to analyse the structure and the state of residual stresses in the samples made of rolled AW-2024 and AW-7075 aluminium alloy plates, prior to machine cutting and after the process of milling under various machining conditions. The state of stresses was evaluated on the basis of measurements by means of sin2vF X-ray diffractometry and layer removal method. Furthermore, top layer microstructures were compared in half-finished product, machined product, and core material samples.

Influence of technological parameters and type of drill bit on the accuracy of holes machining in carbon fibrous composites

The increasing interest in composite materials determines to conduct the research allowing to neutralize the negative effects of the machining process. The paper presents an analysis of the influence of technological parameters and the type of drill bits on the quality of drilled holes in carbon fibrous composites.

Influence of Machining Strategies and Technological History of Semi-Finished Product on the Deformation of Thin-Wall Elements After Milling

The paper presents an analysis of the influence of machining strategy and the technological history of semi-finished product on the deformation of thin-walled elements made of aluminium alloy EN-AW 2024 after milling. As a part of this research work, five machining strategies are analysed. Additionally, the rolling direction of the plate (longitudinal and transversal) is taken into account as a technological history. During the research, the focus is set on the effects of the machining strategies i.e. HPC, HSM and conventional machining as well as their combinations on the post-machining stresses and deformations. Each of these strategies has a different range of technological parameters, which results in differences in machining efficiency and introduces post-machining stresses to the surface layer of the workpiece that vary in values and nature (i.e. compressive stresses or tensile stresses). The conducted study shows that larger deformations were obtained for transversal rolling direction in each analyzed case. The lowest deformation both for transversal and longitudinal rolling direction were achieved for the HSM and CM strategy.