Thread Cutting Tool With Finishing Edges for Smoother Internal Threads

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Solution Overview

Problem

Prior art thread cutting taps often produce internal threads with insufficient surface finish, leading to rough surfaces that can crack under dynamic forces.

Innovation Solution

A thread cutting drill tool with a cutting section featuring axially extending chip flutes, lands, and teeth, where crest cutting edges form the primary cutting edges, and front and rear finishing edges smooth the thread flanks, improving surface finish by following behind the crest cutting edges during operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional thread cutting taps with interrupted helical threads are used, then the thread cutting process can be performed, but the surface finish of the thread flanks is rough and insufficient

Engineering Contradiction:
Improvesurface finish of thread flanksVSAvoidrough surface causing cracks under dynamic forces
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The cutting tool is segmented into multiple distinct cutting edges along the helical thread, including both roughing cutting edges and finishing cutting edges. This segmentation allows different portions of the tool to perform different functions: roughing edges remove material efficiently while finishing edges smooth the thread flanks, thereby resolving the contradiction between cutting effectiveness and surface finish quality

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The roughing cutting edges perform the preliminary material removal action first, creating the basic thread form. Subsequently, the finishing cutting edges act on the same thread flanks to smooth and refine the surface. This preliminary action followed by finishing action ensures both efficient material removal and high surface quality, addressing the contradiction between cutting capability and surface finish

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4112214A1A thread cutting tool for metal cutting
Publication Date: 2023.01.04 WALTER AG
  • EP4112214A1 patent drawingFigure 1~3
  • EP4112214A1 patent drawingFigure 4a~4c
  • EP4112214A1 patent drawingFigure 5

AI summary

A thread cutting drill tool for metal cutting comprising an elongate main body, which comprises a cutting section (4) extending axially rearward from a front end (1). The cutting section (4) comprises an axially extending chip flute (5), an axially extending land (6), and a plurality of axially spaced teeth (8), wherein each tooth (8) of the plurality of teeth extends from the chip flute (5) across the land (6). Each tooth of the plurality of teeth comprises at least one of an axially forward facing front flank (10) and an axially rearward facing rear flank (11), a radially outward facing crest (12), which crest connects to each of the at least one of the front flank (10) and the rear flank (11), and at least one cutting edge (14, 15, 16). The cutting edges of the plurality of teeth comprises a set of crest cutting edges (14), wherein each crest cutting edge (14) is formed by an intersection of the crest (12) of one respective tooth (8) of the plurality of teeth with the chip flute (5). The cutting edges of the plurality of teeth comprises a set of front finishing edges (15), wherein each front finishing edge (15) is formed by an intersection of the front flank (10) of one respective tooth (8) of the plurality of teeth with the chip flute (5). The cutting edges of the plurality of teeth comprises a set of rear finishing edges (16), wherein each rear finishing edge (16) is formed by an intersection of the rear flank (11) of one respective tooth (8) of the plurality of teeth with the chip flute (5). A most forward tooth (9) of the plurality of teeth comprises a first single cutting edge, wherein the first single cutting edge is one of the crest cutting edges (14) of the set of crest cutting edges.