How To Set CNC Feeds and Speeds

spindle speed for cutting wood

Feed rate and speed are two very important parameters in CNC processing. They together affect the cutting efficiency and quality of CNC machines. So what are feed rate and speed?

CNC Feeds and Speeds

Definitions:

  •  Feed Rate:  This refers to the speed of CNC router bits moving, usually measured in inches per minute (IPM) or millimeters per minute (MMPM). The feed rate determines the volume of material cut from the workpiece per unit of time. It directly affects the cutting depth and accuracy.
  • Speed: Also known as cutting speed, it refers to the distance the cutting tools move on the workpiece surface per unit time. It is usually measured in revolutions per minute (RPM). The spindle speed directly affects the cutting speed and cutting effect.

cnc router feeds and speeds

4 Key Factors To Affect Feed Rate and Speed

  • Workpiece Material: Feed rate and speed are related to the hardness of the workpiece. For example, softer materials such as wood require higher spindle rotary speeds, while harder materials such as aluminum require lower spindle speeds.
  • CNC router bits used: The router bits type, number of flutes, diameter, material, and coating of the CNC tool affect the cutting speed. For example, carbide router bits need higher speeds and feeds than high-speed steel CNC cutting tools. Large diameter router bits require lower speeds compared to small diameter router tools.
  • Cutting Depth: The depth of per cut affects the feed rate setting. Deeper cutting generally requires lower feed rates to avoid overloading the tool and CNC machine.
  • CNC Machine Quality: The overall quality and precision of CNC machines will affect cutting speeds and feeds.so we suggest to buy good quality CNC machines, if you have enougth budget.

spindle speed for cutting wood

double flute spiral aluminum cutting bits

How to set feed rates and speeds: 

  • Wood: Wood is relatively soft and easy to cut, so a higher spindle speed is required when cutting wood so that the surface can get a smooth finishing. It is usually set between 18,000-24,000 RPM. The feed rate can also be influenced on the number of CNC router bits flutes and the hardness of the wood and is directly related to the depth per cut.
  • Plastic: A medium-to-high spindle speed is required, usually set at around 18,000 RPM, which can prevent the tool from overheating.
  • Aluminum: Aluminum is harder and requires a lower spindle speed. Feed rate and speed depend on the number of flutes. The speed of Single flute end mills aluminum is generally set at around 12,000 RPM, while the speed of double flute spiral aluminum cutting bits is set at around 7,000 RPM.
  • Foam:  Generally, the router bits used to cut foam are relatively large, so the spindle speed should not exceed 6,000 RPM.
  • Engraving: For engraving cutters such as V-tip bits and ball nose router bits, it is recommended to set the spindle speed between 18,000-24,000 RPM and the feed rate to 3-5 meters per minute.

Single flute end mills aluminum

speeds and feeds

 

 

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