Milling Methods: Up or Conventional Milling, Down or Climb Milling

Milling Methods

Milling is a process of metal cutting by means of a multi-teeth rotating tool, called cutter. The form of each tooth of the cutter is the same as that of single point tool. Each tooth after taking a cut comes in operation again after some interval of time. 

This allows the tooth to cool down before the next cutting operation is done by it. This minimizes the effect of the heat developed in cutting on the cutting edge. With cylindrical cutters, the following two methods are commonly used for cutting operation.

Milling Methods: Up or Conventional Milling, Down or Climb Milling

1. Up or Conventional Milling: 

In this method of milling, the cutter rotates in a direction opposite to that in which work is fed.

2. Down or Climb Milling: 

In this method the direction of rotation of the cutter coincides with the direction of work feed.

The relative directions of movements of the cutter and work should be noted at the point of contact between the two. In the conventional milling the chip thickness increases as the cut proceeds and in case of climb milling the chip thickness decreases as the cut proceeds. I.e. the chip thickness is zero at start of the cut and maximum at the end of the cut in conventional milling where as it is a reverse case in climb milling.

The section of a particular method of the above two, depends upon the nature of work. 

The conventional milling is commonly used for machining castings and forgings since this method enables the cutter to dig in and start the cut below the hard upper surface.

The climb milling is particularly useful for finishing operations and small work, such as slot cutting, milling grooves, slitting etc. It gives a better surface finish if there is no backlash in feeding mechanism of the table and the work is rigidly held.

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