Multi-spindle drilling of Al2024 alloy and the effect of TiAlN and TiSiN-coated carbide drills for productivity improvement

Abstract

High precision drilling is required to ensure the structural integrity of the aircraft. Therefore, strict quality controls are required to ensure optimum hole quality since hundreds of thousands of holes are drilled into different aircraft structures. The large number of holes required for riveting means that their installation must be carried out in a fast and precise manner. This can be achieved using multi-head drilling tools that can drill several holes simultaneously. The current study investigated the use of a multi-spindle drill head that can produce three holes simultaneously. Uncoated carbide and TiAlN-and TiSiN-coated carbide drills were used to assess cutting forces, hole surface roughness, burr formations and tool condition when machining Al2024 aerospace alloy under dry machining conditions. Analysis of variance was employed for estimating the relationships between the input parameters (spindle speed, feed and tool coating) and the studied hole quality metrics. Further, a regression model was developed with a regression coefficient (R 2 ) of more than 90% for the prediction of measured responses. Interestingly, better results in lower thrust force and surface roughness were obtained using the uncoated carbide drills compared with TiAlN and TiSiN. While the performance of TiAlN was found to be better than those obtained from TiSiN.

Effect of Cutting Parameters and Tool Geometry on the Performance Analysis of One-Shot Drilling Process of AA2024-T3

“…Table 2 shows the technical specifications for the drill bits used in this study. All the drilling experiments were performed on AA2024-T3, which is the commonly used alloy in the aerospace industry [1,28]. The thickness of the workpiece material was 10 mm, and the dimensions were 200 × 150 mm 2 .…”

The Effect of TiN-, TiCN-, TiAlN-, and TiSiN Coated Tools on the Surface Defects and Geometric Tolerances of Holes in Multi-Spindle Drilling of Al2024 Alloy

“…This is in agreement with the machinery's handbook, where it was recommended that for the twist drills with sizes ranging from 3.175 to 6.35 (mm), the recommended feed range is 0.05-0.15 (mm/rev), and the higher feed should be used for materials like brass or aluminum for better results [45]. In addition, the hole deterioration due to the increase in the feed is likely due to the higher thrust force [46,47]. However, the spindle speed and the feed did not affect the perpendicularity error, as evident from the ANOVA result in Table 4.…”

Assessment of Hole Quality, Thermal Analysis, and Chip Formation during Dry Drilling Process of Gray Cast Iron ASTM A48

“…The process parameters, such as feed rate, spindle speed, cutting fluid, tool diameter, and chip formation play a key role in hole quality [3,4]. Similarly, an appropriate selection of machine setup and cutting tools during drilling operations is essential to avoid rapid tool wear and low-quality holes [5][6][7]. In addition, inappropriate process parameters can produce torque and undesired thermal stresses on the workpiece and cutting tool, which leads to undesirable distortion and hence reduces tool life and hole quality [8].…”