In CNC aluminum machining and other metal material machining processes, the setting of cutting parameters is crucial for improving machining accuracy. CNC aluminum machining, as part of CNC metal machining, requires special attention to the selection and optimization of cutting parameters to ensure machining quality and efficiency.
Setting Spindle Speed
The reasonable setting of spindle speed is the key to achieving efficient machining and improving machining quality. When machining metal materials with CNC machines, four technical points should be considered, which is particularly important for CNC aluminum machining.
First, material properties. Different metal materials have different hardness, toughness, thermal conductivity and other cutting characteristics, which directly affect the cutting force, cutting temperature and material removal rate. When setting the spindle speed, it is necessary to fully consider the material characteristics and select the appropriate speed range. Especially in CNC aluminum machining, due to the low hardness and high thermal conductivity characteristics of aluminum, a higher spindle speed can be chosen to achieve faster cutting speeds, thus improving machining efficiency and surface finish.
Second, tool type and diameter. Tool type and diameter determine the spindle speed. To ensure that the cutting speed is within a reasonable range, larger tool diameters require faster spindle speeds.
Third, cutting speed. Cutting speed refers to the length of the tool cutting over the unit time, is one of the important reference of the spindle speed. The appropriate spindle speed can be calculated based on the cutting speed formula.
Fourth, cutting force and cutting temperature. Cutting force is the force experienced by the tool during cutting and is related to spindle speed and feed rate. Excessive cutting force will lead to increased tool wear, machining accuracy decline. Cutting temperature will affect the tool life and machining surface quality, so spindle speed should be set to avoid causing excessive cutting temperature.
Setting Feed Rate
The feed rate directly impacts the precision and smoothness of machined parts during metal material CNC machining. Four factors should be considered when setting the feed rate.
First, material hardness. For higher hardness of the material, a slower feed rate is required to reduce the cutting force and the impact of thermal deformation. For lower hardness of the material, a faster feed rate can be used to improve production efficiency.
Second, the machining method. For milling, the feed rate is mainly influenced by the cutting force and temperature. When the cutting force is high or cutting temperature is elevated, the feed rate should be slowed down to ensure tool life and processing quality. For turning, the feed rate is mainly determined by the cutting speed and time. A faster cutting speed allows for a quicker feed rate, to ensure the cutting surface quality and machining accuracy.
For drilling, the feed rate is mainly determined by drill diameter, cutting fluid supply and material hardness. A smaller drill diameter can accommodate a faster feed rate, while insufficient cutting fluid supply may require a slower feed rate.
Third, the characteristics of the workpiece. The shape, size and surface roughness requirements of the workpiece will affect the choice of feed rate. Large workpieces or those that need to maintain high surface quality, you need to apply a slower feed rate to ensure machining accuracy and surface quality.
Fourth, use the cutting force control system to adjust the feed rate. Real-time monitoring of the cutting force, adjust the feed rate, when the cutting force exceeds the set range, the system automatically adjusts the feed rate to protect the tool and machine tool, and improve machining quality.
Setting Cutting Speed
Cutting speed, the linear speed generated by the spindle tool’s rotation, should be set based on a thorough understanding of the material’s characteristics, such as hardness, toughness, and thermal conductivity, along with machining requirements like surface finish and precision. For high-speed steel materials, cutting speeds can range from 20 to 130 m/min; for carbide materials, from 20 to 160 m/min; and for tungsten steel materials, from 30 to 150 m/min.
Controlling Feed Rate
Feed rate, the displacement of the tool relative to the workpiece in the feed direction, is a critical parameter in metal material machining that affects machining quality. For conventional machining centers, feed rates can range from 30 to 1,400 mm/min. For high-performance machining centers, feed rates can be set between 150 and 2,000 mm/min.
