Why is cutting speed important in machining?
- Tool wear and service life
Choosing the right speed reduces the load on the tool, increases its service life and so lowers the cost of tools. A cutting speed that is too high leads to increased wear and can even cause the tool to break. - Heat generation
A lot of heat is generated when working with steel. If the speed is set too high, the tool may overheat and lose its hardness. - Surface quality
The correct setting ensures clean cutting areas. Values that are too low or too high can lead to chatter marks, built-up edges or a poor surface finish. - Process reliability
Particularly with hardened and tempered steels, the correct setting is crucial for achieving consistent and reproducible results.
Calculating cutting speed
The cutting speed is calculated from the diameter and rotational speed using this formula:
Example:
Diameter: 12 mm
Speed: 3,000 1/min
vc = (3.14 × 12 × 3,000) / 1,000
vc = 113.04 m/min
Key:
vc = cutting speed [m/min]
π = pi (the mathematical constant)
d = tool diameter [mm]
n = rotational speed [1/min]
The difference between cutting speed and feed rate
Cutting speed and feed rate are two key parameters in machining which describe different movements. Whilst the cutting speed refers to the cutting edge of the tool, the feed rate (f) describes the speed at which the tool penetrates the workpiece or advances along the machining direction. It determines how much material is removed per unit of time and has a significant influence on chip formation, surface quality and the cutting forces involved.
Help with the calculation: The Meusburger cutting data calculator
Finding the correct cutting values is easy
Step 1: Select tool
From our wide range of cutting tools, select the tool you wish to use for machining your material, depending on the machining method (milling, drilling, thread cutting, reaming). Also select the appropriate tool diameter.
Step 2: Select machining method
In the next step, specify how the workpiece is to be machined (e.g. milling). In addition, please specify here the material to be machined, including the exact material number.
The result
Once all the data has been entered, the cutting data calculator automatically displays the values for tool diameter, cutting speed and feed. You will also be given a reference value for the rotational speed. You can then simply email the values to yourself.
Step 1: Select tool
From our wide range of cutting tools, select the tool you wish to use for machining your material, depending on the machining method (milling, drilling, thread cutting, reaming). Also select the appropriate tool diameter.
Step 2: Select machining method
In the next step, specify how the workpiece is to be machined (e.g. milling). In addition, please specify here the material to be machined, including the exact material number.
The result
Once all the data has been entered, the cutting data calculator automatically displays the values for tool diameter, cutting speed and feed. You will also be given a reference value for the rotational speed. You can then simply email the values to yourself.
Step 1: Select tool
From our wide range of cutting tools, select the tool you wish to use for machining your material, depending on the machining method (milling, drilling, thread cutting, reaming). Also select the appropriate tool diameter.
Step 2: Select machining method
In the next step, specify how the workpiece is to be machined (e.g. milling). In addition, please specify here the material to be machined, including the exact material number.
The result
Once all the data has been entered, the cutting data calculator automatically displays the values for tool diameter, cutting speed and feed. You will also be given a reference value for the rotational speed. You can then simply email the values to yourself.
Factors affecting cutting speed
The material
The material has a significant influence on the choice of cutting speed. Hard and dense materials, such as carbide, generate higher cutting forces and cause greater tool wear, which is why lower cutting speeds are required. Soft materials with good machinability on the other hand allow for higher cutting speeds and more cost-effective machining. Chip formation also affects process safety and heat generation.
The general rule is: the higher the hardness of the material, the lower the cutting speed should be.
The machining method
The machining method affects the load on the tool and therefore the choice of cutting speed. When milling, a higher rotational speed is usually possible. When drilling, deep hole drilling or for thread cutting and thread forming, due to the higher thermal and tool loads lower values must be selected. Reaming is carried out at medium to low cutting speeds in order to achieve high precision.
The cooling
Cooling reduces heat and friction during machining, thereby extending the service life of the tool. The inner coolant supply is particularly effective, as it cools the cutting edge directly. Minimum quantity lubrication can also effectively reduce friction. In general, adequate cooling enables higher cutting speeds and a more stable machining process.
The tool
Another key factor in choosing the cutting speed is the tool material. It determines which speeds are technically feasible and how well the tool can withstand the resulting loads. HSS tools (high-speed steel) are relatively sensitive to heat and are therefore only suitable for lower cutting speeds. Carbide tools, on the other hand, offer high wear resistance and heat resistance, which means that significantly higher cutting speeds can be achieved. Adjusting the tool material to the cutting speed is therefore crucial for cost-effective and reliable machining.
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