Mechanical Engineering - Production Engineering - Discussion

In orthogonal cutting, the cutting edge of the tool is perpendicular to the axis of rotation of w/p i.e. 90 deg, while in oblique cutting, cutting edge is inclined at an angle to the w/p rotating axis. The drilling operation, the drill bit has a point angle, which is 118 degree for general purpose, hence it is oblique cutting. For a drilling operation to be orthogonal, the point angle should be 180 deg, which is not possible as a point angle is necessarily made less than 180 to centre the w/p in the material.

If the cutting edge of the tool is perpendicular to the cutting velocity vector it is orthogonal machining otherwise oblique machining. Examples of orthogonal machining are chiselling, broaching, sawing, parting off operations whereas drilling, shaping, planing, turning and boring are the examples of oblique machining.

For a process to be Orthogonal machining process the angle between the cutting speed vector and the chip flow direction is 90 degrees and also the cutting edge must be perpendicular to cutting velocity.

Because it is three dimensional cutting and cutting edge of tool is oriented at an acute angle to tool feed and it is less concentration of heat, so drilling presses require less heat.

The drill bit is fixed in the drilling machine in 90 degree, but oblique cutting is less than 90 degree then how can we say oblique cutting is the right answer.

Oblique means when the cutting edge of the tool less then 90 degree to the direction of tool travel. Orthogonal--- perpendicular to the direction of tool.

If the face of cutting is perpendicular to the feed motion that cutting is said to an oblique this is exactly right answer for Drilling operation.

If we consider the only partial angle of point angle. It comes to less than 90 degrees. That is the condition for oblique cutting.

Drill makes 90 degrees angle with the workpiece, then how it will be oblique cutting?

I think it will be orthogonal cutting.

Drilling is a simple cutting.

It is said to be oblique cutting angle is less than 90. Hence it is a simple cutting.