- 1. Different directions
If the rotating direction of the touch part of the milling cutter and the workpiece is the same as the feed direction of the workpiece, it will be down milling. If the rotating direction of the touch part of the milling cutter and the workpiece is different from the feed direction of the workpiece, it will be up-milling. Always keep one side of the thread tightly fitted, and otherwise during down milling.
- 2. Different uses
During down milling, the cutter teeth are always cut from the surface of the workpiece, so it is not suitable for titanium machining hard-skinned workpieces. In up-milling, because of the greater conflict between the cutter tooth and the workpiece, the cold and hard phenomenon of the machined surface is more severe.
- 3. Different power consumption
The average cutting thickness during down milling is large, the cutting deformation is small, and the power consumption is less compared with up-cut milling (when milling carbon steel, power consumption can be reduced by 5%, and milling difficult-to-process materials can be reduced by 14%).
- 4. The journey of the tooth on the workpiece is different
When climb milling, the cutting thickness of each tool is gradually changed from small to large. When the cutter tooth just touches the workpiece, the cutting thickness is zero. Only when the cutter tooth slides a certain distance on the cutting surface left by the previous cutter tooth, and the cutting thickness reaches a certain value, the cutter tooth really starts cutting.
up-cut milling makes the cutting thickness gradually change from large to small, and the sliding distance of the tooth titanium machining on the cutting surface is also very small. And when down milling, the journey of the tooth on the workpiece is shorter than that of up milling. Therefore, under the same cutting conditions, when using up milling, the tool is easy to wear.
In up-milling, the straight component of the milling force during up-milling will lift the workpiece, and the conflict between the sliding of the cutter teeth and the machined surface will increase, because the direction of the horizontal cutting force acting on the workpiece by the milling cutter is opposite to the direction of the workpiece feed movement, so the work The screw rod and the nut can always keep one side of the thread tightly attached.
Otherwise during down milling, because the direction of the horizontal milling force and the direction of the workpiece feed movement are the same, when the tool tooth exerts a large force on the workpiece, because of the gap between the table screw and the nut, the table will shift. This will not only destroy the smoothness of the cutting process, affect the titanium machining quality of the workpiece, but also damage the tool when it is severe.
When milling castings and forgings, the cutter teeth first touch the black skin, which aggravates the tool wear; but the straight milling component of down milling presses the workpiece against the worktable, the cutter teeth slide with the machined surface, and the conflict phenomenon is small. It is beneficial to wear, reduce work hardening and reduce surface roughness. Therefore, when the gap between the screw and nut of the worktable is adjusted to less than 0.03mm, or when milling thin and long workpieces, down milling should be used.