Which is better, down milling or down milling?

    The milling cutter's cutting edge is subjected to an impact load each time it is plunged. In order to successfully mill, you must consider the correct contact between the cutting edge and the material during cutting in one cut. In the milling process, the workpiece is fed in the same or opposite direction as the rotation direction of the milling cutter, which will affect the cutting in and out of the milling and whether the method of up milling or down milling is adopted.

1definition

Down milling:The cutting speed direction of the tool is the same as the moving direction of the workpiece.

Back milling:The cutting speed direction of the tool is opposite to the moving direction of the workpiece.

The golden rule of milling-From thick to thin

    When milling, be sure to consider chip formation. The decisive factor for chip formation is the position of the milling cutter. Be sure to strive to form thick chips when the cutting edge is cut in and thin chips when the cutting edge is cut out to ensure a stable milling process and make the chip thickness as small as possible.

2Discrimination method

When milling the external contour of the workpiece, feed clockwise along the external contour of the workpiece, programming is down milling, programming counterclockwise along the external contour of the workpiece, feeding is down milling; when milling the internal contour of the workpiece, follow the internal contour Feeding and programming in the counterclockwise direction is down milling. Programming and feeding in the clockwise direction along the contour of the workpiece is up milling.

3Features of up and down milling

① When cutting down, the cutting thickness of each tool is由Small to large gradually changing.Also, the sliding distance of the cutter teeth on the cutting surface is small. At the same time, the distance traveled by the cutter teeth on the workpiece is shorter than that of up milling. Therefore, under the same cutting conditions, the tool is prone to wear when using down milling.

② During up-milling, the table screw and nut can always keep one side of the thread tightly fit.During down milling, because the direction of the horizontal milling force is consistent with the workpiece feed motion direction, the force of the cutter teeth on the workpiece is large, so that there is a gap between the table screw and the nut and it cannot be closely fitted.

③When counter-milling, the cold hardening of the processed surface is serious.

④ Down milling should not be used to process hard-skinned workpieces.

⑤ The average cutting thickness during down milling is large, and the cutting deformation is small.

⑥ The feed direction of the tool has different requirements on the workpiece fixture. During up-milling, the workpiece holder must be able to resist lifting forces. It must be able to resist downforce during down milling. Down milling and down milling have their own characteristics. In the actual production process, after each cutting, full consideration should be given to the correct way of contact between the cutting edge and the material when cutting in and out, before deciding whether to use down milling or up milling.