Surface Topography Description of Threads Made with Turning on Inconel 718 Shafts

Abstract

The technology of producing threads, especially in materials that are difficult to cut, is a rare subject of research and scientific publications. The requirements for the production of these elements apply not only to the geometry, but also to the quality of the surface obtained. This is particularly important in the aviation industry, where the durability of the threaded connection affects passenger safety. Due to the design of the thread, the quality of its surface is assessed visually in industrial practice. The authors of this study decided to examine the surface topography of external threads made by turning on Inconel 718 shafts in order to confirm the visual evaluation, as well as to investigate the influence of such factors as cutting speed, turning direction and type of profile. Three types of contours were cut for the research: triangular, trapezoidal symmetrical and trapezoidal asymmetrical. Turning of each was carried out twice at cutting speeds vc = 17 m/min and vc = 30 m/min. On each of the threads, the side surface of the profile made in the direction of the insert feed and the opposite surface were examined. The surface texture parameters Sa, Sq, Sp, Sv, Sz, Ssk and Sku were determined and compared. It was noticed that the thread surfaces show a tendency to irregular roughness, which was confirmed by the analysis of the Sku and Ssk coefficients. The sides of the contours made in the direction of the insert feed are characterized by a higher roughness in relation to the opposite sides, which may result from high cutting forces and difficulties with chip evacuation. With the cutting speed being considered, lower values of Sa and Sq were obtained for vc = 17 m/min, which differed from the visual assessment, proving its high subjectivity.

Influence of Innovative Post-Weld Finishing Method on Bead Surface Quality

“…In order to conduct research related to the analysis of the impact of an innovative method of finishing (removal) on butt weld faces in steel specimens and its effect on the main parameters of the geometric structure of the surface, measurements of surface roughness were performed using a non-contact optical method. Additionally, visual representation of the roughness and surface topography of the selected area was obtained using an Alicona Infinite Focus G6 [ 24 , 25 , 26 , 27 , 28 ]. Both the 2D profile parameters (Ra, Rz, Rt, Rv, Rz) and thestereometric characteristics of the 3D surface roughness (Sq, Sp, Sv, Sz, Sa) determining its functional properties were tested.…”

“…The anode voltage and anode current were set at 20 kV and 4 mA, respectively. representation of the roughness and surface topography of the selected area was obtained using an Alicona Infinite Focus G6 [24][25][26][27][28]. Both the 2D profile parameters (Ra, Rz, Rt, Rv, Rz) and thestereometric characteristics of the 3D surface roughness (Sq, Sp, Sv, Sz, Sa) determining its functional properties were tested.…”

Analytical Model of Tapered Thread Made by Turning from Different Machinability Workpieces

“…The mechanism of closed-loop chip formation is modeled by evaluating the effect of the process vibrations. The study [56] examined the influence of such factors as cutting speed and turning direction on the quality of external thread surface made by turning on Inconel 718 shafts. The work [33] describes the kinematic analysis of turning a noncircular cross-section workpiece, using mathematical parameters to optimize the efficiency of the process.…”

On-Machine Measurement as a Factor Affecting the Sustainability of the Machining Process

“…In addition to the typically economic aspects, it is crucial to produce quality compliant parts the first time. Measurement automation is a significant improvement in this matter [35].…”