Metal cutting: How cutting speed affects it

Metal cutting is one of the most basic processing methods in the machinery manufacturing industry. Metal cutting refers to the use of metal cutting tools on metal cutting machines to remove excess metal from the surface of the workpiece to achieve processing that meets the predetermined shape, dimensional accuracy and surface quality requirements.

Cutting speed is a very important parameter in the metal cutting process and has a direct impact on cutting quality and processing efficiency. Choosing the right cutting speed can improve processing efficiency, extend tool life and ensure processing quality. This article will analyze the impact of cutting speed on metal cutting quality and provide some suggestions for optimizing cutting speed selection.

1.Impact of cutting speed on metal cutting quality

1) Tool wear

Cutting speed has a direct impact on tool wear. The higher the cutting speed, the higher the temperature generated at the cutting interface and the more severe the tool wear. This is especially important in high-speed machining, because the tool wear rate will be faster during high-speed machining.

2) Heat generation

Cutting speed has a great impact on the heat generated during machining. High temperature will have an adverse effect on the tool and workpiece material. Overheating will cause tool softening, accelerated wear, and even thermal damage to the workpiece surface.

3) Surface treatment

Cutting speed will affect the quality of the machined surface. Generally speaking, the higher the cutting speed, the better the surface finish. However, there is an optimal range for cutting speed, exceeding which may result in poor surface quality due to factors such as tool deflection and overheating.

4) Chip Formation

Cutting speed affects chip formation and evacuation. Proper chip formation is critical to achieving a good surface finish and preventing issues such as chip re-cutting. Different cutting speeds may result in variations in chip morphology and evacuation efficiency.

5) Material Removal Rate

Cutting speed is an important factor in determining the material removal rate (MRR). The higher the cutting speed, the higher the MRR, which is beneficial when productivity is the primary consideration. However, this needs to be balanced with considerations of tool life and surface finish.

6) Tool Force and Power Consumption

Cutting speed affects the cutting forces experienced by the tool and the power required for machining. Higher cutting speeds generally reduce cutting forces, which is beneficial for minimizing tool deflection and power consumption.

7) Material Hardening

For some materials, especially some heat-treated steels, high cutting speeds can lead to material hardening. This is a phenomenon where the material hardens due to rapid heating and cooling during the cutting process. It affects tool life and machinability.

8) Vibration and chatter

Cutting speed is a factor that causes vibration and chatter during machining. Excessive cutting speed may lead to unstable cutting conditions, resulting in vibration, which has a negative impact on surface finish and tool life.

9) Tool engagement

Cutting speed determines the frequency of engagement between the cutting tool and the workpiece material. The engagement frequency affects the formation of built-up edge (BUE), chip thickness, and the overall stability of the machining process.

2.Optimizing the selection of cutting speed

1) Material properties

Different metal materials have different cutting characteristics. It is necessary to select the appropriate cutting speed according to the hardness, toughness, plasticity and other characteristics of the material; generally speaking, harder metal materials such as stainless steel and high-speed steel should use lower cutting speeds to reduce heat accumulation and tool wear; for softer metal materials such as aluminum alloys and copper, the cutting speed can be appropriately increased.

2) Cutting depth and feed rate

The selection of cutting speed also needs to consider parameters such as cutting depth and feed rate. Generally speaking, when the cutting depth is large, a lower cutting speed should be selected to reduce heat accumulation and tool wear; when the cutting depth is small or the feed rate is large, the cutting speed can be appropriately increased.

3) Tool type and quality

Tools of different types and qualities have different requirements for cutting speeds. High-speed steel tools are usually suitable for medium and low-speed cutting, while carbide and ceramic tools are suitable for high-speed cutting. When selecting tools, the appropriate cutting speed should be determined based on their wear resistance and heat resistance.

Cutting speed plays a vital role in metal cutting and directly affects cutting quality and processing efficiency. Selecting the right cutting speed can ensure the quality of the processed surface, control cutting force, and extend tool life. Therefore, in practical applications, it is necessary to comprehensively consider factors such as the characteristics of metal materials, cutting depth and feed rate, as well as tool type and quality, to optimize the selection of cutting speed and achieve the best processing effect.