Climb or conventional, what do I need?

When you begin to process your part and a face milling operation is necessary, what type of milling do you want to do? Should you use climb milling or conventional milling, and what is the difference?

The definition for climb milling is the tool rotating clockwise, climb milling goes with the rotation. When climb milling, the insert hits the material at the top of the cut, and the thickness of the chip decreases as the insert cuts.

The definition for conventional milling is the cutter rotates against the direction of the feed and the cutting tooth enters the workpiece in a manner that creates a chip that’s thicker at the beginning and thinner at the end.

There are also other terms that apply to these types of milling. Climb milling is also referred to as down milling, while conventional milling is referred to as up milling.

In most cases climb milling improves finish, increases tool life, and generates less heat in the cut. Chips also evacuate away from the cutter faster, creating less deflection. On the other hand, conventional milling leads to poor surface finishes and increased heat in the cut, which reduces tool life and makes chips not as easily evacuated from the cutting zone.

So, the question is, which one will you use? The part, the fixture, and the geometry of the part will dictate what you must do to produce a quality part. However, in my opinion, you should always choose climb milling if you can. The benefits are in your favor considering less chip hammering, less heat, greater tool life, and better surface finishes. They’ll lead to a better-quality part!

When choosing your cutter path, I suggest looking at the down milling process. You can also discuss this with your favorite cutting tool supplier as well. They have professionals who will help you to make your decisions in the best interest of your part quality.

CMR Consultants