CNC machining of special-shaped parts is a complex and delicate job that requires comprehensive consideration of multiple factors, from selecting the right tool to arranging the machining process reasonably, to clamping and positioning, each step requires meticulous operation. Only by strictly following the specifications can the machining quality and accuracy be ensured and production efficiency be improved.
(1) Tool selection
When CNC machining special-shaped parts, the choice of tool is crucial. Tool materials with high hardness, high precision and high wear resistance should be selected, such as carbide or high-speed steel tools. Different shapes and material properties of special-shaped parts require different types of tools. For complex curved surface machining, ball-end tools or round-nose tools should be used; for parts with simpler contours, flat-bottom tools are a better choice. The geometric angle of the tool also needs to be selected according to the specific machining requirements so that the tool can effectively contact and machine the workpiece.
Reasonable processing process division is the key to ensuring machining accuracy. We can divide the process into three types.
(1) Tool concentration sequencing method
Divide the process according to the tool used, use the same tool to complete all the parts that can be processed, and then change to another tool.
(2) Processing part sequencing method
Divide the special-shaped parts into internal shape, external shape, curved surface and other parts according to the structural characteristics, and process them step by step.
(3) Rough and fine processing sequencing method
For parts that are prone to processing deformation, perform correction after rough processing, and then perform fine processing.
When we perform CNC processing, the processing sequence should follow some principles. First, process the internal shape and cavity first, and then process the external shape.
Then the processes with the same positioning, clamping method or the same tool are better connected to reduce the number of repeated positioning and tool changes.
When multiple processes are performed in the same installation, the process that causes less damage to the rigidity of the workpiece should be arranged first.
(1) Program inspection
Before formal processing, be sure to carefully check the processing program to ensure its correctness. We can use simulation software to optimize and verify the program to prevent processing failure or workpiece damage caused by program errors.
(2) Control cutting parameters
Select appropriate cutting speed, feed speed and cutting depth according to the workpiece material and tool type. Cutting speed and feed speed will affect the tool life and processing quality. We must strictly control the parameters and pay attention to monitoring the cutting load to prevent tool damage or workpiece deformation due to excessive cutting force.
(3) Monitoring and adjustment
During CNC processing, the tool wear should be monitored at all times and the cutting parameters should be adjusted in time. When the tool is found to be severely worn, the tool should be replaced without affecting the processing quality and accuracy.
