Installation and application of the most popular C

Installation and application of NC end milling cutter in automobile parts processing

the end milling cutter used in CNC machining center mostly adopts the spring clamping method, which is in a cantilever state when used. In the process of milling, sometimes the end milling cutter may gradually extend from the tool holder. If the output signal is inaccurate, it may even fall completely, resulting in the scrapping of the workpiece. The reason is generally because there is an oil film between the inner hole of the tool holder and the outer diameter of the end milling cutter shank, especially on May 15 (7). Two experiments show that the class is completely different from the experimental sample. On May 15, all experimental machines purchased during this period have preferential delivery and rebate, Caused by insufficient clamping force. When end mills leave the factory, they usually use antirust oil. If water-insoluble cutting oil is used during cutting, a layer of mist oil film will also be attached to the inner hole of the tool holder. When there is oil film on the NC tool holder and the tool holder, the tool holder is difficult to firmly clamp the tool holder, and the milling cutter is easy to loosen and fall off during processing. Therefore, before clamping the end milling cutter, the shank of the end milling cutter and the inner hole of the cutter clamp should be cleaned with cleaning fluid, and then clamped after wiping dry

when the diameter of the end milling cutter is large, even if the tool handle and tool holder are clean, the tool drop accident may still occur. At this time, the tool handle with a flat notch and the corresponding side locking method should be selected

another problem that may occur after the end milling cutter is clamped is that the processing neutral milling cutter breaks at the end of the tool holder. The reason is generally because the tool holder has been used for too long, and the end of the tool holder has been worn into a cone. At this time, a new tool holder should be replaced

II Vibration of NC end milling cutter

because there is a small gap between the end milling cutter and the tool holder, the NC cutter may vibrate in the processing process. Vibration will make the cutting amount of the circular edge of the end mill uneven, and the cutting expansion will increase than the original set value, affecting the machining accuracy and tool life. However, when the processed groove width is too small, the tool can also be vibrated purposefully, and the required groove width can be obtained by increasing the cutting expansion. However, in this case, the maximum amplitude of the end mill should be limited to less than 0.02mm, otherwise stable cutting cannot be carried out. In normal processing, the smaller the vibration of the neutral milling cutter, the better

when tool vibration occurs, it should be considered to reduce the cutting speed and feed speed. If there is still large vibration after both have been reduced by 40%, it should be considered to reduce the tool amount

if the machining system resonates, the reason may be that the cutting speed is too large, the feed speed is too small, the rigidity of the tool system is insufficient, the clamping force of the workpiece is not enough, and the workpiece shape or clamping method. At this time, measures such as adjusting the cutting amount, increasing the rigidity of the NC tool system, and improving the feed speed should be taken

III End cutting of NC end milling cutter

in the NC milling of workpiece cavities such as molds, when the cutting point is a concave part or deep cavity, it is necessary to lengthen the extension of the end milling cutter. If long edge end milling cutter is used, due to the large deflection of NC cutter, it is easy to produce vibration and cause damage of NC cutter. Therefore, in the machining process, if only the blade near the end of the NC tool is required to participate in cutting, it is best to choose the short edge long shank end mill with a long total length of the NC tool. When using large-diameter end mills to process workpieces on horizontal CNC machine tools, due to the large deformation caused by the self weight of the cutters, great attention should be paid to the problems that are prone to occur in end edge cutting. When long edge end mills must be used, the cutting speed and feed speed need to be greatly reduced

IV Selection of cutting parameters

the selection of cutting speed mainly depends on the material of the workpiece being processed; The choice of feed speed mainly depends on the material of the workpiece being processed and the diameter of the end mill. The tool samples of some foreign tool manufacturers are attached with the selection table of NC tool cutting parameters for reference. However, the selection of cutting parameters is also affected by many factors, such as machine tools, CNC tool systems, the shape of the workpiece to be machined, and the clamping method. The cutting speed and feed speed should be adjusted appropriately according to the actual situation

when taking the life of NC tool as the priority factor, the cutting speed and feed speed can be appropriately reduced; When the chip is not well off the edge, the cutting speed can be appropriately increased

v Selection of cutting mode

using forward milling is conducive to preventing blade damage and improving the service life of NC tools. But there are two points to be noted: ① if ordinary machine tools are used for processing, try to eliminate the gap of the feeding mechanism; ② When the oxide film or other hardened layer formed by casting and forging process remains on the surface of the workpiece, reverse milling should be adopted