Core Operating Mechanism of Forming and フライス加工

Thread Taps

Thread Mills

Structural Characteristics & Key Designs

Machine Thread Taps

Lead-In Section: The tap head features a conical lead-in segment that guides the tool into the workpiece, reducing cutting resistance and preventing chipping at the thread’s start.

Flute Designs (Critical for Chip Removal): Taps are classified by flute helix into three types (Figure1), with chip evacuation direction dictating application:

Figure 1 Flute designs of machine thread taps

Right-hand flutes (Figure 1a): Eject chips upward, ideal for blind holes (where chips cannot exit downward).

Left-hand flutes (Figure 1c): Direct chips downward, suitable for through holes (allowing free chip exit).

Straight flutes (Figure 1b): Flexible chip evacuation (both up and down), usable for both through and blind holes.

Flute Quantity: Minimum 3 flutes (Figure 1), with options for more flutes (e.g., 4 flutes in Figure 2) for enhanced chip removal. High-helix flutes (Figure 3) are used for high-efficiency machining to further improve chip discharge.

Figure 2 A thread tap with 4 flutes

Integral Structure: The cutting edges and tool shank are a single unit, with no blade replacements needed—one tap size corresponds to one thread specification.

          

Thread Mills: Diverse Structures for Versatile Thread Processing

Single-Edge Thread Mills (Borrowed Thread Turning Tools)

Multi-Edge (Transverse) Thread Mills

1.Integrated Internal Thread Mills (Figure 5b): Integral tool body with 3+ cutting edges. The smallest model has a 5.8mm tooth 回转 diameter, enabling milling of M8 and larger small-diameter internal threads.

2.Modular Internal Thread Mills (Figure 5c, Figure 6): Consist of a tool body and indexable inserts (3 edges typical). Designed for medium-diameter internal threads (e.g., 2mm pitch, ≥20mm major diameter).

3.Tool Disk Thread Mills (Figure 7): Mount multiple indexable triangular thread inserts (5 pieces shown) on a disk, with a cutting edge 回转 diameter ≥40mm. Ideal for large-diameter internal and external threads.

Longitudinal Multi-Edge Thread Mills (Thread Chasers)

1.Single-Edge Inlaid Thread Chasers (Figure 8): Triangular inserts with positioning sides, compatible with multiple thread standards on the same tool body. Pitch-specific inserts are required for different pitches of the same standard. A compact model with an 11.5mm cutting edge diameter can mill internal threads with a bottom hole diameter ≥12mm. Figure 9 shows its use for external thread milling.

2.Double-Edge Inlaid Thread Chasers (Figure 10): Two variants:

180° dual inserts (Figure 10), larger diameter, for external threads and large-aperture internal threads.Single insert with double edges, smaller diameter, for smaller-aperture internal threads.

Core Comparison of Taps and Thread Mills

Tool Selection Guidelines

1. Choose Thread Taps for: Small/medium-diameter internal threads (≤M20), batch processing, and conventional materials (carbon steel, cast iron). Cost-effective and efficient for standard through/blind hole threading.
2. Choose Thread Mills for: Large-diameter threads (≥M40), external threads, taper threads (e.g., NPT), high-precision requirements, or hard-to-cut materials (stainless steel, high-temperature alloys). Offers superior chip control, thread quality, and tool life.
3. Specialized Scenarios: For small-diameter precision internal threads (≤M8), use integrated transverse multi-edge thread mills. For large threads or frequent pitch changes, modular thread chasers or tool disk mills reduce overall costs.

結論