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Up Milling Definition:
This is also called as conventional milling or Climb up milling.
In which the cutter and feed move in the opposite direction i.e the rotary cutter moves against the feed.
With reference to the adjacent figure, the cutter rotates in the anti-clockwise direction, while the direction of feed is from right to left.
So, due to this opposite motion, the width of the cutting chips gradually increases from minimum to maximum.
There is massive friction between the cutter and workpiece which results in generating a large amount of heat.
Up Milling Advantages:
This is a safe operation because It has no tendency to drag the workpiece into the cutter.
Up Milling Application:
Generally used for milling of casting and forging.
Down Milling Definition:
This is also called a Climb down milling.
In the case of this milling, the cutter rotates in the same direction as that of the feed.
There is less friction involved between the cutter and the workpiece as both.
Therefore, the cutter and feed are moving in the same direction. This small amount of friction results in the generation of minimum heat.
Here, the thickness of the chip varies from a maximum to a minimum during the process.
Down Milling Advantages:
This machine poses a longer tool life.
This machine produces a good surface finish.
Down Milling Application:
Difference Between Up and Down Milling Machine:
|Sl. No||Up Milling||Down Milling|
|1.||This machine is also called as conventional milling.||This is called a climb down milling.|
|2.||The cutting forces act upward.||The cutting forces act downward.|
|3.||Mostly used for rough cutting operations.||This is used for finishing operations.|
|4.||Due to the more tool wear rate, the durability of the tool is less.||Due to less tool wear rate, the durability of the tool is more.|
|5.||The tool wear rate is more, as the direction of the rotary cutter is against the feed.||The tool wear rate is less, as the direction of a cutter is the same direction as the feed.|
|6.||This process is mostly used in the conventional way of cutting the surface.||Nowadays, This is a better operation choice then up milling machine.|
|7.||Effective cooling is not required during cutting action.||Effective cooling is possible during cutting action.|
|8.||The cutter rotates against the direction of travel of the workpiece during metal cutting.||The cutter rotates in the same direction of travel of the workpiece during metal cutting.|
|9.||Poor surface finish.||Good surface finish.|
|10.||It requires a large amount of force compared to down milling.||Here, there is a requirement of less force.|
|11.||This machine is mostly used cutting of brass, bronze, and ferrous materials.||And whereas this is applicable to aluminum and aluminum alloys.|
|12.||Chip thickness starts at zero and increases towards the end of the cut.||Chip thickness is maximum initially and reduces to zero at the end of the cut.|