3. Differences Between Up and Down Milling
The described types of milling have substantial differences that make manufacturers pick a process for a particular component.
1. Scope of Application
It is already stated that up milling is rather hard and rough machining. Thus, it is typically required for milling, casting, and forging. Some extra tough materials such as titanium, bronze, or stainless steel are machined by up milling because such processes enable them to apply more force to a component.
And, there is no risk of surface deterioration because of melting of excessive physical force. In contrast, down milling is a thinner and even soft process. It is generally used for finishing operations, as it offers greater smoothness than up milling does.
Sawing, grooving, slotting, keyway cutting, and other similar operations are also included in the scope of applications of down milling. Most frequently, materials such as aluminum, with a low melting point and low hardness, are to be machined with the use of up milling.
2. Surface Quality
Generally, under certain circumstances and with proper settings adjustment, both types of processes can offer great surface smoothness. However, up milling is not fully designed for great finishes, as just opposite directions of movement of a workpiece and a rotating tool make it almost impossible to cut off the thinnest pieces.
In contrast, down milling is intended to apply lower forces, cut thinner metal chips, and work with metal that is often required to be polished to perfection.
As a result, the surface quality of a component manufactured with the use of down milling will always be on a completely another level than such with up milling.
![CNC milling part](https://ecoreprap.com/wp-content/uploads/2022/02/CNC-milling-part.jpg)
3. Movement of Worktable
We hope that you are not confused with us showcasing infographics with pointing out the direction of a workpiece feeding. In a broad sense, milling is shaping a stationary workpiece with a movable cutting tool.
While moving a workpiece into a stationary cutter is called turning. Up and down milling may imply that a cutter rotates and is fed simultaneously in the same direction or in the opposite. It is still these two milling processes, but with a stationary workpiece.
Technically, the movement of a worktable is not crucial. You may find similar methods as described in other manufacturing operations. Just stick to rotating along the feed direction, or in the opposite direction. In essence, with proper settings, moving a worktable and a cutting tool, or one of them only does not impact the quality of milling.
But, it is definitely easier to program the movement of only one of the constituents of the process.
4. Cutter Wear
This one is simple. Up milling requires high forces to be applied to a workpiece. Apparently, it increases the tension that a cutter experiences. Additionally, friction conceives extra heat, which also deteriorates tooling. As a result, even expensive cutters may have their sharpness reduced or even break shortly.
In contrast, down milling is a more gentle process, typically applied under low tension and low friction to soft metals such as aluminum and its alloys. Even relatively cheap tooling may last for a longer period if used in down milling, compared to up milling.
![CNC Milling Cutters](https://ecoreprap.com/wp-content/uploads/2022/02/CNC-Milling-Cutters.jpg)
5. Power Consumption
Basically, power is the last concern of factories’ owners. However, in case you are curious, we may reveal this secret to you based on our experience. Power consumption during up milling slightly exceeds down milling consumption.
It is explained with the rubbing action of more friction, which requires more energy. The difference is not worth paying attention to, but it is still present.