Abstract: Reaming is a process of improving the quality of already drilled holes by means of cutting tools called reamer A reamer is a rotating cutting tool generally of cylindrical shape which is used to enlarge and finish holes to accurate dimensions to previously formed hole. It is a multiple edge cutting tool having the cutting edge on its periphery. A reamer consists of three mean parts 1. Fluted section 2. Neck 3. Shank The fluted part consists of chamfer, starting taper, sizing section and back taper length. Chamfer length or bevel lead insures proper and easy entry of the reamer into the hole. The main cutting action of reamer is done by starting taper, the sizing section and to guide the reamers and also smooth or size the hole. The back taper reduces friction between reamers and the whole surface. The industrial relevance of bore holes with small diameters and high length-to-diameter ratios rises with the growing requirements on parts and the tendency of components for downsizing. Examples for components requiring deep holes with small diameters exist in the automotive industry; for the production of injectors for fuel injection as well as for medical and biomedical parts. Based on growing functional requirements, for example with the increase in injection pressure to improve the efficiency of the combustion process in diesel engines, the requirements on the surface integrity of bore holes also increase. To meet these requirements, an adaption of the deep hole drilling process is necessary. In this paper the influence of tool geometry, coating and cutting data on the bore hole quality and tool wear will be presented. An improvement in the efficiency of the cutting process requires high tool performance. For the tool performance the microscopic cutting edge shape is very important. By preparing the cutting edge the tool performance can be improved due to the reduction of the cutting edge chipping and the creation of a defined stable edge rounding. In this study, the influence of a cutting edge preparation on the deep hole drilling process is investigated. The aim is to increase the feed rate by a specific cutting edge design. Drilling is probably the most common machining operation applied to composites since components made out of composite materials are usually near net shaped and require only holes for assembly integration.

Keywords: optimizing the reamer design stopping reamer breakage and tool cost reduction.