The influence of a number of points on results of measurements of a turbine blade

Abstract

Purpose The purpose of this paper was to determine the influence of a number of measured points on results of measurements of turbine blades, which are the parts of aircraft engines. The selection of a number of points is the part of a measurement strategy in the coordinate measuring technique and determines the accuracy of measurements. Design/methodology/approach Numerical and experimental investigations were conducted. The measurements were simulated using different numbers of measured points. The simulated measurements were performed for the selected dispersion of measured points. The dispersion reflected the inaccuracy of a manufacturing process of the considered product and the uncertainty of measurements of curvilinear surfaces. To verify the accuracy of the numerical studies, experimental research was conducted. The real measurements were conducted using the selected coordinate measuring machine. Findings The gained results following the simulations can be very useful when selecting the appropriate number of measured points. The chosen number of points may be used during real measurements of turbine blades conducted on coordinate measuring machines. The results of numerical research indicate that there should be used the average radii of leading and trailing edges to increase the accuracy of measurements. The results of real coordinate measurements confirmed the results of simulation studies. Originality/value The main novelty of the paper is the presented methodology for determining the influence of measured points on results of measurements. The presented methodology helps the user of a coordinate measuring system select the appropriate measurement strategy of free-form surfaces applied in the aerospace industry.

Cutting layer and cutting forces in a 5-axis milling of sculptured surfaces using the toroidal cutter

“…The total force exerted by the tool on the workpiece is defined as the resultant of the cutting forces exerted by all the tool cutting blades [6,11,15,19,20]. The components of the total force are determined by the rectangular projection of this force along the direction of the individual motions associated with the kinematics of the cutting process.…”

“…For simulation tests the method of a tool direct transformation in a CAD environment was applied, which was used among others in [1,4,6]. This method is based on mathematical models of solids used in CAD/CAM systems.…”

“…One of the latest research in the area of 5-axis milling was carried out by Ozturk, Budak et al [4][5][6] and Erdim and Lazoglu et al [7,8]. These studies concerned an analytical modeling of the cut layer geometry and they obtained data that were later used to predict the cutting force and optimize the 5-axis milling process.…”

“…Actually, since the cut geometry with ball-end cutters always occurs on a spherical cap, the cut geometry does not vary as a function of tool axis orientation in 5-axis milling. The influences of the tool axis orientation on the engagement parameters when using ball-end cutters have been investigated [4][5][6][12][13][14], but this effect has not been investigated using a toroidal cutter [10], [15,16].…”

Precision CNC Machining of Femoral Component of Knee Implant: A Case Study

“…For the components of the replacement implant, suitable metals or non-metallic materials are chosen and properly machined in order to resemble the natural shape of the knee as much as possible and allow for proper joint motion, resistance to wear and corrosion and biocompatibility. The machined components should adhere to highly restrictive regulations and exhibit considerable durability [2][3][4][5][6].…”