Internal thread processing is a core process in mechanical manufacturing, widely used in automotive components, aerospace, precision instruments, and other fields. With technological advancements, internal thread processing methods have evolved from traditional manual tapping to CNC automated processing. This article will deeply analyze 7 mainstream internal thread processing methods, helping you quickly master key techniques and applicable scenarios.
Tapping Processing: Classic Manual and Machine Tapping Techniques
Process Flow: Drilling → Selecting tap (straight flute/spiral flute) → Manual or machine tapping → Deburring.
Advantages: Low cost, suitable for small batch production.
Disadvantages: Prone to tool breakage, requires high operator skill.
Application: Small hole diameters (M6 and below), blind hole processing.
Tips: When processing stainless steel, use cobalt taps, and combine with emulsified coolant to improve efficiency by 30%.
Turning Processing: High-Precision CNC Lathe Internal Thread Solutions
Key Points: Use a 60° thread cutting tool, spindle speed ≤ 800 rpm, G76 command for layered cutting.
Advantages: Precision up to IT7 grade, surface roughness Ra 1.6.
Case Study: A valve manufacturing company used a CAK6150 CNC lathe, increasing processing efficiency by 200%.
Milling Processing: Efficient Solution for Complex Large Diameter Internal Threads
Technical Breakthrough: Single-tooth thread milling cutters enable processing of M24-M120 threads. Spiral interpolation strategy reduces tool wear.
Advantages: Processing speed 3 times faster than tapping, precision ±0.02mm.
Applicable Scenarios: Aerospace titanium alloy parts, deep cavity structures.
Extrusion Forming: Chip-Free Processing to Enhance Thread Strength
Principle: Threads are formed through plastic deformation, increasing material density by 20%.
Advantages: Improved fatigue strength, no chip contamination.
Limitations: Suitable only for materials like aluminum alloy, low-carbon steel, etc.
Grinding Processing: Ultimate Solution for Ultra-Precision Internal Threads
Technical Parameters: Diamond grinding wheel with 800# grain size, processing precision up to IT5 grade.
Application: Hydraulic servo valve, optical instrument thread pairs.
Cost: Equipment investment over 2 million RMB, suitable for mass production of high-value-added parts.
Special Processing Solutions (EDM/Cool Forming)
Electrical Discharge Machining (EDM): Can process hard carbide internal threads, surface roughness Ra 0.8.
Cold Extrusion Forming: Preferred for automotive wheel hub bolt hole processing, efficiency up to 200 pieces per hour.
How to Choose the Best Internal Thread Processing Method?
Material Hardness: For materials with hardness below HRC50, choose turning or milling; for higher hardness, grinding is required.
Batch Requirements: Use tapping for small batches, cold extrusion for large batches.
Precision Level: Choose tapping for IT8 grade or below, and grinding for IT6 grade or above.
Conclusion
Mastering the core technologies of internal thread processing can significantly improve production efficiency and product quality. Whether using traditional tapping or five-axis coordinated milling, selecting the appropriate process will help reduce costs and increase efficiency.
