Exploring CNC Machining: The Art of Precision Manufacturing
CNC machining is a subtractive manufacturing process that typically uses computer control and machine tools to remove layers of material from a workpiece, producing custom-designed parts. This process suits various manufacturing tasks, from simple to highly complex, and can handle materials such as metals, plastics, wood, foam, and composites. It is widely applied in the automotive, aerospace, medical devices, and consumer electronics industries.
01 Characteristics of CNC Machining
✔ High degree of automation, resulting in extremely high production efficiency.
✔ High adaptability to CNC machining objects.
✔ High precision in machining quality and minimal time-based error accuracy.
✔ Stable and consistent machining quality.
02 CNC Machining Processes and Applications
Different machining methods can be selected based on the material and requirements of the workpiece. A clear understanding of common machining techniques and their applications helps identify the most suitable approach for processing components.
(1) Turning
—— Material cutting is achieved through the rotation of the workpiece and the tool's linear feed motion. Form-turning tools can be used to machine-rotate curved surfaces.
Turning is relatively productive. The cutting process is relatively stable, and the tools are relatively simple.
The general machining accuracy of turning ranges from IT11 to IT6, and the surface roughness ranges from 12.5 to 0.8 μm. During finish turning, the accuracy can reach from IT6 to IT5, and the roughness can reach from 0.4 to 0.1 μm.
Application Scope: Drilling center holes, drilling, reaming, tapping threads, turning external circles, boring holes, turning end faces, turning grooves, turning formed surfaces, turning conical surfaces, knurling, and turning threads.
(2) Milling
—— Material removal is achieved through the relative movement between a rotating multi-edged tool (milling cutter) and the workpiece.
· Climb Milling: When the horizontal component of the milling force is in the same direction as the workpiece's feed direction. The cutting thickness decreases from large to small, and the tool cuts into the material from the surface. It provides a good surface finish, but feed surging may occur (requires eliminating lead screw clearance).
· Up Milling: The horizontal component of the milling force is opposite to the workpiece's feed direction. The cutting thickness gradually increases from zero, and the tool cuts into the material from the interior. The machining process is stable, but tool wear is faster.
Application Scope: Milling planes, milling steps, milling grooves, milling formed surfaces, milling spiral grooves, milling gears, and cutting off.
(3) Drilling
—— A process for machining various internal holes on a drilling machine.
Drilling typically offers lower precision (IT12–IT11) with a surface roughness of Ra5.0–6.3μm. Post-drilling, semi-finishing, and finishing are often achieved via reaming, which provides higher precision (IT9–IT6) and finer surface roughness (Ra1.6–0.4μm).
Application Scope: Drilling, reaming, tapping, countersinking, and spot facing.
03 Main Application Industries
Aerospace: Requires components with extremely high precision and repeatability, including turbine blades in engines and tooling for manufacturing other components.
Automotive and Machinery Manufacturing: Involves producing high-precision molds for casting parts (e.g., engine mounts) or machining high-tolerance components (e.g., pistons).
Medical: Implantable devices are often designed to fit the shape of human organs and must be manufactured from advanced alloys.
Various processing techniques have been developed with the development of machining to the present day and the improvement of market requirements. When selecting a machining process, considerations can be made from multiple aspects, including the surface shape of the workpiece, dimensional accuracy, positional accuracy, surface roughness, etc.
