Before understanding the difference between up milling and down milling it is important to first understand the definition, advantages, and application of each type in detail. Let us start with up milling.
What is Up Milling?
This is also called as conventional milling or Climb up milling. Here, the cutter and feed move in the opposite direction i.e the rotary cutter moves against the feed.
Credits : ENGRAMRITKUMAR
With reference to the above 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.
Advantage of Up Milling:
This is a safe operation because It has no tendency to drag the workpiece into the cutter.
Application of Up Milling:
Generally used for milling of casting and forging.
What is Down Milling?
This is also called a Climb down milling. In the case of down milling, the cutter rotates in the same direction as that of the feed. There is less friction involved between the cutter and the workpiece.
Credits : ENGRAMRITKUMAR
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:
- It poses a longer tool life.
- It produces a good surface finish.
Down Milling Application:
This type of machine is generally used for finishing the operation like sawing, grooving, keyway cutting, etc.
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 in the same direction as the feed. |
| 6. | This process is mostly used as 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 chips are generated. | 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 for cutting of brass, bronze, and ferrous materials. | 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. |
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