Difference between Feed Rate and Cutting Speed in CNC Machining

Difference between Feed Rate and Cutting Speed in CNC Machining

CNC machining is a manufacturing process is the process where the metal piece is sheared until the desired shape is achieved. This process is computer-driven, but to get it right, the machine operator must be aware of the shearing capability and moving speed of the machine. In simple terms, they must be familiar with the feed rate and cutting speed of the CNC machine. This post gives you a brief understanding of the difference between feed rate and cutting speed in CNC machines.

What is the difference between the Feed Rate and the Cutting Speed?

Cutting speed and feed rate maybe two different terms, which work simultaneously. Cutting speed is considered the speed of a tool that cuts the workpiece. In comparison, the feed rate is the distance traveled by the tool in one revolution of the spindle. Therefore, the feed rate is considered as the velocity at which the cutter is fed.

Cutting Speed

Cutting speed, also known as the surface speed, is the relative velocity between the cutting tool and the workpiece surface. There is an optimum cutting speed for each material and a set of machining conditions that differ between materials. This optimum feature of the cutting speed ensures the accuracy offered by the CNC machining process.

Factors to Be Considered For Cutting Speed in CNC Machining

Optimum cutting speed is a necessity to improve the efficiency of CNC machining. As said before, CNC machining is a software-controlled process, and the cutting speed still depends on different factors. The following are a few important ones among them. 

  • Material Being Cut: 

    A CNC lathe machine is compatible with different materials like metals, wood, glass, and so on. These materials differ in their thickness and hardness, which highly affects the cutting tool and the cutting speed. If the material is too soft, then the cutting tool material will tend to cut the material quickly with high accuracy and cutting speed. In contrast, the cutting speed will be slow for durable and h4 materials.
  • Material of the Cutting Tool:

    The CNC machine uses different types of lathe tools. This tool can be made from soft or hard materials. The strength of the cutting tool contributes to optimum cutting speed. For instance, the cutting tool made of high-strength material can be used for high-speed cutting, whereas cutting too made of soft material can be used for low-speed cutting. As in the latter case, soft material cutting tools may wear out easily at high speeds.
  • Tool Life: 

    The life of the tool is another essential factor that needs to be considered for cutting speed. Tool life is basically a period in which the cutting tool works effectively. Tool life decides the accuracy of the workpiece and the cutting speed.

Feed Rate

Feed rate is basically the distance at which the tool travels during its single spindle revolution. It is defined as the velocity at which the cutter is fed. It is represented in the units of distance per revolution turning.

Factors to be considered for Feed Rate in CNC Machining

Feed rate has fewer effects on the process, but it is essential for the perfect finishing of the workpiece. To regulate the optimum value of the workpiece, machinists consider the factors given below:

  • Type of the Tool: 

    The type of tool that is being used for cutting the material is highly based on the type of material being fed. Hence the tool must be suitable for the material being fed.
  • Surface Finishing of the Work Piece: 

    Surface roughness increases when the feed rate increases. Hence the feed rate is slowed down to get a smooth surface finishing.
  • Cut Width: 

    Cut width less than half diameter may thin the chip. This causes manufacturing defects. To reduce this issue, the feed rate must increase.
  • Use of TPI: 

    TPI stands for thread per inch, which is proportional to the feed rate. Feed rate increases as per the range of thread pitch on screws being used.

Feed rate and cutting speed are only two factors to improve the efficiency of your CNC machine process. There are several other factors that may contribute to. However, you need not worry about these factors when you partner with a trusted and experienced player like Brogan & Patrick. The company takes pride in its technology investments and resource pool comprising CNC machining programmers and experienced machine operators. You can contact the experts today to discuss your machining needs. 


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