Abstract
This article dissects four core CNC machining processes—milling, turning, drilling, and grinding—covering technical principles, equipment selection, and industry applications. With visual diagrams and SEO-optimized keywords, it offers the manufacturing professionals a practical guide to process selection, precision control, and cost optimization for enhanced production efficiency.
1. Milling: The Core of Complex Surface Machining
1.1 Technical Principles
Milling uses rotating cutters to machine planes, slots, or 3D surfaces, supporting multi-axis (3/5-axis) operations. Typical equipment: vertical/horizontal machining centers.Key Parameters:
- Spindle speed: 800–24,000rpm
- Feed rate: 50–5,000mm/min
- Precision: ±0.005–0.05mm
1.2 Applications
- Aerospace: 5-axis milling of turbine blades (surface roughness Ra≤0.8μm)
- Mold Manufacturing: High-precision machining of injection mold cavities (tolerance ±0.01mm)
- Medical Devices: Machining complex surfaces of joint prostheses
Visual: Milling Workflow Diagram
graph LR
A[CAM Programming] --> B[Workpiece Clamping] --> C[Cutter Positioning] --> D[Layered Milling] --> E[Precision Inspection]2. Turning: Precision Machining for Rotational Parts
2.1 Technical Principles
The workpiece rotates while the tool feeds linearly to machine cylindrical, conical, or threaded surfaces. Typical equipment: CNC lathes, turn-mill composite machines.Advantages:
- Multi-process machining in one clamping (turning + milling + drilling)
- Threading precision up to ISO 4H class
2.2 Applications
- Automotive: Precision turning of engine crankshafts (roundness ≤0.003mm)
- Electronics: High-speed turning of connector terminals (40% efficiency gain)
- Precision Instruments: Nano-level turning of micro shafts
Visual: Turning Process Schematic
graph TD
A[Spindle Rotation] --> B[Tool Transverse Feed]
A --> C[Tailstock Support]
B --> D[Cutting Formation] 3. Drilling & Boring: Full-Spectrum Hole Machining
3.1 Drilling: Rapid Production of Standard Holes
- Equipment: CNC drilling machines, machining centers
- Key Points:
- Drill speed: 1,000–15,000rpm (aluminum)
- Internal cooling drills reduce tool wear
3.2 Boring: High-Precision Hole Finishing
- Precision: Hole tolerance up to H7, surface roughness Ra≤1.6μm
- Applications: Deep-hole boring of hydraulic valve bodies (depth-diameter ratio >20:1)
Comparison Table: Drilling vs. Boring
| Process | Precision Range | Typical Hole Size | Tool Life |
| Drilling | ±0.1–0.3mm | φ1–φ50mm | 500–1,000 parts |
| Boring | ±0.005–0.02mm | φ20–φ300mm | 2,000–5,000 parts |
4. Grinding: Ultimate Surface Precision Assurance
4.1 Technical Features
Grinding uses abrasive tools (wheels/stones) for micro-cutting, achieving micron-level precision (±0.001mm) and surface roughness Ra≤0.2μm.
4.2 Applications
- Aero-Engines: Mirror grinding of turbine journals (roundness ≤0.0005mm)
- Precision Molds: Lapping of ejector pin holes (Ra≤0.1μm)
Visual: Precision Comparison Chart
barChart
title Precision Comparison of Machining Processes
xAxis Process Types
yAxis Precision (μm)
series Precision Values
Milling: 5-50
Turning: 2-20
Grinding: 0.1-5Conclusion
Choosing the right CNC process directly impacts efficiency and cost. Milling excels at complex shapes, turning at rotational parts, drilling/boring at hole features, and grinding at ultimate precision. Strategic combinations (e.g., 5-axis milling + precision grinding) can significantly enhance yield rates and competitiveness in high-end manufacturing.
