A Study of the Kinematics System in Drilling Inconel 718 for Improving of Hole Quality in the Aviation and Space Industries

Abstract

This article discusses experimental results concerning the quality of through holes drilled in Inconel 718. The tests involved hole cutting under 27 different conditions using different values of the feed per revolution and spindle speed, and different types of kinematic system. The drilling was performed on a CTX Alpha 500 universal turning center using tools with internal coolant supply. Three kinematic systems were considered for hole cutting. The first, based on the driven tool holder, had a stationary workpiece and a rotating and linearly fed tool. In the second, where drilling was based on the spindle rotations, the workpiece rotated while the tool moved along a straight line. In the third system, the workpiece and the tool rotated in opposite directions; the tool also performed a linear motion. The study aimed to assess the quality of holes on the basis of the following output parameters: the hole diameter, cylindricity and straightness errors, and the surface texture. A multifactorial statistical analysis was used to determine how the hole quality was dependent on the process parameters and the type of drilling kinematics. The findings confirm that the kinematic system, as well as the feed per revolution, are the key factors affecting the quality of holes drilled in Inconel 718. The analysis of the hole drilling process for Inconel 718, performed using a CNC turning center, shows that the third kinematic system was the best option as all the four parameters describing the hole quality had the lowest values. The best results were obtained in the 6th (n = 637 rpm, fn = 0.075 mm/rev, KIN III) and 8th experiments (n = 955 rpm, fn = 0.075 mm/rev, KIN II), because the parameters were then the lowest, with the scatter of results being up to 30%.

Effect of Choice of Drilling Kinematic System on Cylindricity Deviation, Roundness Deviation, Diameter Error and Surface Roughness of Holes in Brass Alloy

“…A decrease in roundness deviation of 50-77%, cylindricity deviation of 13-51% and surface roughness of 47% was observed with cryogenic drilling. Several articles [23][24][25][26] examined how three different input parameters-spindle speed, feed per revolution and three different drilling strategies-affect cylindricity deviation, straightness deviation, roundness deviation and hole diameter error. The above studies show that the use of a suitable drilling strategy can significantly reduce the individual output parameters evaluated.…”

Parametric Analysis of Tool Wear, Surface Roughness and Energy Consumption during Turning of Inconel 718 under Dry, Wet and MQL Conditions

“…Inconel 718 exhibits superior properties like high hardness, high strength, and resistance to high temperatures, fatigue, and corrosion, as shown in Table 1. In Inconel 718, the presence of iron, chromium, nickel, and other constituents makes it resistant to corrosion and wear [6,7]. Due to these properties, Inconel 718 has found applications in different fields like the aerospace and marine industries.…”

Multi-Objective Optimization of Process Parameters during Micro-Milling of Nickel-Based Alloy Inconel 718 Using Taguchi-Grey Relation Integrated Approach

“…Blades, discs, and other components of aircraft engines have been made with Inconel 718 due to its superior mechanical properties including strength, corrosion resistance, and high temperature creep resistance [ 5 ]. Nickel, chromium, iron, and other constituents make Inconel 718 resistant to wear and corrosion [ 6 , 7 ]. Inconel 718’s low machinability requires deeper investigation of the manufacturing process.…”