CNC Up Milling VS Down Milling, What is the difference?

CNC Up Milling VS Down Milling, What is the difference?

Up milling, as well as down milling, are two typical CNC milling processes, from the interpretations, follow us to contrast them and also find out about the difference between up milling and down milling.

Up milling (conventional milling) is the milling procedure when the milling cutter cut the workpiece, the instructions of reducing speed are contrary to that of the CNC milling part feeding in the direction of.

Down milling (climb milling) refers to the milling procedure in which the rotating direction of the milling cutter is the same as the feed instructions of the work surface, that is, the element of the force exerted by the milling cutter on the work surface in the feed instructions coincides as the feed direction of the workpiece.

Motion of worktable

  • Down milling: the horizontal element force is the same as the feed direction of the worktable, when the gap between the feed screw of the worktable as well as the nut is large, the worktable is simple to axial wobble, causing the cutter teeth to break, shaft curved, the work surface and component are displaced as well as also the machine tool is harmed.
  • Up milling: the force is opposite to the feed direction of the worktable, which will not relocate.

Surface top quality

  • Down milling: when the reducing edge of the milling cutter cuts into the workpiece for the first time, the chip thickness is the largest, and slowly minimizes to 0. The blade wear is slow, and also the surface high quality is excellent.
  • Up milling: the chip density is transforming from 0 to the optimum. The cutter can not cut into the component at the start, the job solidifying will certainly decrease the surface top quality.

Cutter wear: faster in up milling or conventional milling

  • Down milling: the cutting is from thick to slim, and also the cutter teeth reduced from the surface that not have been machined, which is beneficial to the use of the milling cutter.
  • Up milling: when the cutter teeth contact the work surface, they can’t cut into the metal layer quickly, however slide for a short distance on the workpiece surface. In the moving process, as a result of solid friction, a great deal of heat will certainly be produced. At the same time, the hard layer is simple to form on the surface area to be machined, which reduces the resilience of the cutter.

Power usage

Power consumed in feed movement: up milling is greater than onward grating. Under the same cutting problem, the power usage of down milling is 5%– 15% lower.


  • Down milling: the force in the vertical instructions applied by the milling cutter on the part is always downward, which has an important result on the milling part, cutting continuously, ideal for hard to secure and also slender and thin sheet kind work surface.
  • Up milling: the vertical component pressure is upwards, workpiece needs bigger securing pressure.

Chip removal

Down milling is preferable for chip management.

Down milling is a general choice to improve surface area coating as well as guarantee precision. If there is a hard layer, slag deposit on the reducing surface and also the surface area of the workpiece is unequal, for instance, when processing built blank, the up milling needs to be utilized.

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