CNC machining is flexible and highly automatic, especially suitable for machining curve and curved surface parts with complex contour and shape, as well as complex box and prism parts with a large number of holes and grooves. In the case of multiple varieties and small batch production, the use of CNC machining can obtain higher economic benefits.
The processing technology of large-scale CNC is basically the same as that of common processing, but it has its own characteristics. Therefore, when designing the NC machining process of parts, we should not only follow the principle of good flexibility and high automation of NC machining, especially suitable for machining the curve and curved surface parts with complex contour and shape, as well as the complex box and prism parts with a large number of holes and grooves. In the case of multiple varieties and small batch production, the use of NC machining can obtain higher economic benefits.
The determination of tool setting point and tool change point in large CNC machining center is the starting point of tool movement relative to workpiece. Since the program is also executed from this point, the tool setting point is also called the program starting point or starting point. When programming, the selection of tool setting point should be considered first. When the machining accuracy requirements are not high, some surfaces on the workpiece or fixture can be directly used as the tool alignment surface; when the machining accuracy requirements are high, the tool alignment point should be selected on the design basis or process basis of the part as much as possible, for example, for the parts with hole positioning, the axis of the hole taken as the tool alignment point is more appropriate. The tool setting point must have a certain coordinate relationship with the positioning datum of the workpiece, so as to determine the relationship between the coordinate system of the machine tool and the workpiece. The selection of tool setting point shall facilitate the calculation of coordinate value and the tool setting. During the tool setting, the tool setting point shall coincide with the tool position. The so-called tool point refers to the intersection point of the tool axis and the tool bottom surface for the flat end milling cutter; the ball end milling cutter refers to the ball center of the ball head part; the turning tool refers to the tool tip; the drill bit refers to the drill tip; the line electrode cutting machine tool refers to the focus of the line electrode axis and the part surface. When the tool change is needed in the process of machining, the tool change point shall be specified, and the position of the tool change point shall be set according to the principle that the workpiece, fixture and machine tool shall not be damaged during the tool change.
About the author