English Author: Site Editor Publish Time: 2026-02-25 Origin: Site
The setting of the spindle speed of a CNC vertical lathe needs to comprehensively consider the processing material, tool characteristics, machine tool performance and control mode. Reasonable setting can not only improve processing efficiency, but also effectively extend the service life of the tool and spindle.
Ⅰ. Select the rotational speed reasonably based on the processing material
The requirements for cutting speed vary significantly among different materials. The appropriate spindle speed should be set based on the material of the workpiece.
Soft materials such as aluminum alloy : higher rotational speeds (e.g. 800-1200 rpm) can be adopted to enhance surface finish and processing efficiency
45 # steel and other medium carbon steels : It is recommended to use medium speed (400-600 rpm) for stable cutting
For difficult-to-machine materials such as cast iron and stainless steel : the rotational speed should be reduced to 200-350 rpm to minimize tool wear and heat accumulation
Note: The higher the hardness of the material, the lower the cutting speed should be. Non-ferrous metals can significantly increase the rotational speed.
Ⅱ. optimize the rotational speed parameters in combination with the type of cutting tools
The material and structure of the cutting tool directly affect its ability to withstand rotational speed:
Carbide tools : Compared with high-speed steel tools, they can increase the rotational speed space by approximately 30%
Coated cutting tools : Surface treatment reduces friction and allows for a 10% - 15% increase in rotational speed
Small tip arc radius tool : applicable to a wider speed range, suitable for high-speed cutting in fine machining
Ⅲ. Set rotational speed strategies for different processing stages
| Process type | Suggested rotational speed | Target |
| Rough finish | Take about 70% of the regular value | Ensure torque output at large cutting depths and avoid overload |
| Semifinishing | Increase it to 120% of the regular value | Balance efficiency and surface quality |
| Finish machining | High speed and small cutting depth | Meet the surface roughness requirement of Ra≤1.6 |
During finish machining, the surface quality can be improved by increasing the rotational speed and reducing the feed rate.
Iv. The Impact of Control Methods and System Functions
Constant speed control (G97) : suitable for most conventional processing, directly set the S value (such as S1500)
Constant linear speed control (G96) : It is used for turning outer circles or end faces, maintaining a constant cutting linear speed (such as G96 S100), and the system automatically increases the speed as the diameter decreases
The maximum speed limit must be set in conjunction with the G50 S3000 to prevent the spindle from overspeeding
Spindle ratio adjustment : The actual speed can be adjusted in real time within the range of ±50% to 120%, which is convenient for fine-tuning the cutting state during trial cutting
V. Speed Limits for Special Processing Scenarios
Thread processing : The spindle speed is limited by the encoder response frequency and interpolation operation speed. It is advisable to choose a lower speed to prevent the "random threading" phenomenon
Recommended formula: n screw ≤ n allowable/L (n allowable is the maximum allowable speed of the encoder, and L is the pitch)
Processing of long shafts or thin-walled parts : The rotational speed should be increased to reduce vibration, but the depth of cut and feed rate should be significantly reduced to avoid workpiece deformation
When the old machine tool or the spindle is in poor condition : the rotational speed should be set conservatively, with a focus on checking the spindle accuracy and the lubrication of the guide rail
Ⅵ. Key Points for Safety and Equipment Protection
Avoid problems caused by excessive rotational speed :
The cutting temperature rises sharply, accelerating tool wear and even causing "tool burning"
It causes the workpiece to vibrate (flutter) and affects the surface quality
Excessive centrifugal force may cause the fixture to loosen, posing a safety hazard
Avoid the risk of too low rotational speed :
The tool "squeezes" the material rather than cuts it, resulting in work hardening
Abnormal increase in cutting force can damage the tool life
Adaptive control technology application : It can monitor the spindle load in real time, dynamically adjust the feed rate, and achieve overload protection for the tool and spindle while improving efficiency
