Design and Development of a Self-Aligning Multi-Hole Drilling Machine for Precision Drilling in Thin Plates

Precision drilling of thin plates is a challenging manufacturing operation due to workpiece deflection, misalignment, burr formation, and dimensional inaccuracy. Conventional drilling and multi-spindle drilling machines often fail to maintain consistent hole quality when applied to thin plates with thickness less than 5 mm. This paper presents the design, fabrication, and experimental investigation of a Self-Aligning Multi-Hole Drilling Machine (SAMHDM) developed to improve positional accuracy, surface finish, and productivity during multi-hole drilling operations. The proposed system integrates a mechanically self-aligning fixture with a multi-spindle drilling head to compensate for plate flatness variations and fixture misalignment. Experimental trials were conducted on aluminum 6061 and mild steel plates using drill diameters ranging from 3 mm to 10 mm. Results show a reduction in positional error by up to 70 %, improvement in surface finish by 30 %, and cycle time reduction of approximately 25 % compared to conventional drilling methods. The outcomes demonstrate that the proposed machine is suitable for precision thin-plate drilling applications in small- and medium-scale industries [1–3].