A New Type Of Drill And Its Grinding Technology

Hole drilling is one of the most used methods for material machining. Drilling sequence amount is up to 20-40% of total machining sequences. Therefore, drilling technology (drill, technology and equipment for drill manufacturing) is important research project in machining area.Commonly used drills are these which are with conical flank surface and spiral flank surface. But the grinding motions of the machine tools are very complex for the flank surface of these drills, which can抰 exactly control geometric parameters of the drill points. Up to now, the parameters of these two kinds of drills are still allowed to vary in a wide allowance. Simultaneously, with the development and necessity of high and new technology, micro hole (especially precision micro-hole) is used more and more in products. For the size of micro-hole is small, it is very difficult exactly to make the drill for micro-hole. For existing micro-drill, planar point is commonly used at home and abroad, but which has a series of shortcomings for drilling. So, this project is to study a kind of new drill, the grinding technology and device of new drill, for which the motion of grinding machine is simple, the grinding parameters can be exactly control. This new type of drill can overcome shortcomings of planar drill point, is suited to common drill, and also suited to micro-drill. It is thus clear that the research of the project has strong theory and application significance. The content is part of the project (59775068) financial supported by NSFC (National Natural Science Foundation of China). The thesis study on the following area:.1.D~抏loping history of drill and its grinding technology are reviewed. Grinding methods of flank surfaces of several commonly used drill point are discussed. Developing states and characteristics of drilling technology of micro-hole are summarized. Some shortcomings of planar drill point are analyzed and pointed out. The necessity and feasibility for researching new micro-drill are proposed.2.Drill point is the most important part of a drill for drilling. To research of drill is mainly to research of its point. According to the shortcomings of common used points, to start with analysis of grinding principle and its motion relation, a new kind of drill, which is called as helical point drill, is advanced. The mathematical models of new helical point and flute of the drill are advanced. The process and approaches how to solve these mathematical models and how to get exact grinding parameters are discussed.3.To grind the new dill point it is necessary to develop grinding machine of the new point. It is an important problem how to make the structure of the new grinding machine be mostreasonable, the motion relation be simplest and the manufacturing cost be lowest. To solve this problem, it is necessary to analyze sensitivity of grinding parameters. For analyzing sensitivity of grinding parameters it is mainly to find which grinding parameters are sensitive to geometric parameters of the drill so that the most sensitive parameters are controlled. Then, the aim simplifying motion relation and structure of the grinding machine can be reached. At the same time, theoretical basis can be provided for design and control of grinding machine of helical drill point. The third chapter of the thesis is designed for this reason.4.After analyzing geometric parameters of new drill point and developing their mathematic models, the numerical values of geometric parameters can be quantitatively got. To analyze distribution reasonability of geometric angles of the new drill point, It is helpful to analyze and exactly control the parameters of drill point. Simultaneously, it is reasonable that the distribution of geometric parameters is shown in curve line or curve surface. So, all the changes and distribution of geometric parameters are shown in figures, which can enhance the visibility.5.Chisel edge of drill influences its drilling performance. Firstly, chisel edge has centering funct...