Experimental Study On Drilling Of Aramid Fiber Composites

Aramid composites are of good fatigue resistance, high specific strength and strong design ability,and they are widely applied to aviation and space,automobile industry and military industry.The drilling process is the most common ways to make holes.But because aramid composites have specializations of the anisotropy of fiber,shearing strength at intersection and thermal conductivity,there are some problems of serious wear on drill unsure machining accuracy and processing fault.In view of the difficult processing property of aramid fiber composites.In this paper, the experimental research on drilling force,drilling temperature,machining defects and tool wear of aramid fiber 1414 reinforced epoxy resin composites drilled by ordinary solid carbide twist drill and ultrafine cemented carbide bit. It provides the technical guidance for the hole processing technology of this kind of materials.The main contents of this paper are as follows:The drilling experiment of aramid fiber composite board is made by using the common hard alloy bit and the ultrafine grain cemented carbide bit.The changing process of drilling force produced by two kinds of drills and the influence of drilling parameters on the drilling force are analyzed.And the drilling force produced by two kinds of drill bit is analyzed and compared.Results show:Under the same conditions,the drilling force decreases with the increase of the speed of the spindle, and the opposite trend is presented with the increase of the feed rate.And the drilling force produced by the ultrafine grained cemented carbide bit is smaller than that of the ordinary hard alloy bit by 40% or more.The reasons of the curve of the drilling temperature change caused by the two kinds of drill bits are analyzed.The variation rules of drilling parameters on the drilling temperature are studied,and the drilling temperature of the two kinds of drills are analyzed and compared.Results show : Under the same conditions, the drilling temperature increases with the increase of the spindle speed and decreases with the increase of the feed rate.The drilling temperature produced by the ultra fine grain cemented carbide bit is 85 ? lower than that of the ordinary carbide bit.Comparison and analysis of two different materials of drilling bit aramid fibercomposite material plate produced by the burrs and thermal damage.The experimental results show that the burr and the thermal damage defects of ultrafine cemented carbide drill hole caused by the less.Its processing quality is obviously superior.This paper describes the tool wear patterns and the causes of tool wear during the process of drilling.And comparative analysis of the wear of the two kinds of tool.The results show that the wear of the ultra fine cemented carbide bit is relatively small,which is more suitable for drilling this type of composite material. The wear rate increases with the increase of the spindle speed, and increases with the increase of the feed rate.Found the suitable processing parameters, namely the spindle speed4000r/min, feed rate 90mm/min.