Article Title

A7075-T651 alaşımının sürtünmeli delinmesinde kovan yüksekliğinin malzeme kalınlığına göre araştırılması


The friction drilling process, a non-traditional hole making technique, is widely used for drilling cast materials recently. In friction drilling, a rotating conical tool is applied to penetrate work material and create a bushing in a single step without generating chip. A no – chip drilling process was formed by thermal friction to soften work material principle in which it had the most important features such as no pollution, short machining time and long tool life. In friction drilling the cylindrical rotating tool penetrates the softened material and push the melted material in the below direction and provides forming bush. Once the tool moves further forward to push aside more work material and form the bushing using the cylindrical part of the tool. The shoulder of the tool may contact with the work piece to trim or collar the extruded burr on the bushing. Finally the tool retracts and leaves a hole with a bushing on the work piece. The process is typically applied to ductile sheet metal but there is a lash of research in friction drilling of brittle cast metals. The difference in the brittle and ductile work piece can be seen as the brittle work – material begins to fracture and the ductile work material encompasses the tool. Finally the tool retracts and leaves a hole with a bushing on the work piece. The formed bushing height is about 2-3 times of material wall thickness. The aim of friction drilling is provide clamp load due to bushing formation in thin walled materials. Although the beneficiation of increasing clamp loads of thin wall thickness material there are less experimental studies in the friction drilling area.The aim of this experimental study was investigate the differentiation of bushing height according to the both hole diameter and material thickness. With using 1 HSS tools it was friction drilled 2mm, 4mm, 6mm, 8mm and 10mm thickness of A7075-T651 aluminium alloy. In study they were selected 240, 360 and 480 tool conical angles, 2400 rpm, 3600 rpm and 4800 rpm spindle speeds, 50 mm/min, 75 mm/min and 100 mm/m feed rates, 8 mm ve 10 mm hole diameters. With increasing tool conical angle the bushing height is decreased. With increasing spindle speed, due to spread the material environment of the hole, the bushing height is decreased because of the momentum effect. With increasing hole diameter and work piece material thickness, due to the increasing material volume, bushing height is increased. But the bushing height is not showed a parallel increase to the work piece material thickness.