Milling Operation? | Difference Between Up Milling and Down Milling

What is Milling

Milling is a machining process in which, a rotary cutter is used to remove the material from the workpiece in the direction perpendicular to the axis of rotation. The milling process is done by the machine, which holds bot the tool and workpiece in jig and fixture, known as a milling machine.

There are two ways to cut the material from the workpiece through a milling machine. The first one is named as conventional milling or Up milling and the other one is known as climb milling or down milling.

Difference Between Up-Milling and Down-Milling Operation

Up Milling	Down Milling
In up milling the cutter rotates against the direction of feed.	In Down milling, the cutter rotates with the direction of feed.
It is also known as conventional milling.	It is also known as climb milling.
In this, chip width size is zero at the initial cut and increases with feed.  It is maximum at the end of the feed.	In this cutting process, the chip size is maximum at the start of the cut and decreases with the feed. It is zero at the end of the feed.
In this process, heat is diffused to the workpiece which causes the change in metal properties.	In down milling, most of the heat diffused to the chip does not change the workpiece properties.
In up milling, tool wear is more because the tool runs against the feed.	In this, tool wear is less compared to the up milling, due to the cutter rotating with the feed.
Tool life is low.	Tool life is high.
The cutting chips are carried upward by the tool so-known as up milling.	The chips are carried downward by the tool so-known as down milling.
The cutting chips fall down in front of the cutting tool which again cuts the chips cause less surface finish.	The cutting chips fall down behind the tool. This gives a better surface finish.
Due to upward force by tool, high strength jig and fixture are required to hold the workpiece.	In down milling, downward force act on workpiece normal jig and fixture required.
It is the traditional way of cutting the workpiece.	It is a non-traditional way, but nowadays, down milling is used more than up milling.
High-quality cutting fluid is required because heat diffuses in the workpiece.	In this process heat does not diffuse in the workpiece, so simple cutting fluid is required.
It required a high cutting force compared to down milling.	It required low cutting force.