How to Improve Chip Evacuation in CNC Blind Hole Tapping in Germany: Application of Spiral Flute Taps

In German precision manufacturing, CNC machining centers are widely used for blind hole tapping operations, especially in automotive and mechanical engineering sectors. However, poor chip evacuation remains a critical issue affecting tapping stability.

In blind hole applications, chips cannot exit freely as in through-hole machining. Instead, they tend to accumulate inside the hole. As chip accumulation increases, cutting resistance rises significantly, leading to torque fluctuations. These fluctuations affect thread quality and may accelerate tool wear or cause breakage.

From a machining perspective, the key challenge in blind hole tapping is chip control. If chips are not effectively guided away from the cutting zone, they interfere with the tool-workpiece interaction and reduce process stability.

DIN371 spiral flute taps provide a structural solution. With a spiral angle of approximately 35° (Spiral R35), chips are directed upward along the flute, keeping the cutting area clear. The short thread design (6–15 mm) reduces cutting engagement length and helps lower cutting load.

Key parameters include a size range from M3 to M10, overall lengths of 56–100 mm for rigidity, and a 6H tolerance for consistent thread quality.