Thread Cutting Tap with Selective Chip Breaking for Thread Quality
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Solution Overview
Problem
Existing thread cutting taps produce long chips that cause tool damage, chip jamming, and inferior thread quality due to inadequate chip evacuation and chip breakers affecting surface finish.
Innovation Solution
A thread cutting tap design with selective chip breaking features in some flutes and not others, utilizing chamfers with negative rake angles and non-coated regions to enhance chip breaking while maintaining surface finish quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If chip breaking features are applied on all flutes of the thread cutting tap, then chip breaking efficiency is improved, but surface finish quality deteriorates
Solution Approach 1:
The patent applies chip breaking features selectively to only some flutes (e.g., first and second flutes) while leaving other flutes (e.g., third flute) without chip breaking features. This local differentiation allows the tap to achieve effective chip breaking where needed while maintaining superior surface finish on threads cut by flutes without chip breakers, thus resolving the contradiction between chip breaking efficiency and surface finish quality
2Object-generated harmful factors
If chip breakers are applied on the rake face, then chip evacuation is improved, but thread quality deteriorates
Solution Approach 1:
The patent implements chip breakers on only some of the flutes rather than all flutes. This selective application ensures that chip evacuation is improved in the flutes equipped with chip breakers, while the flutes without chip breakers produce threads with higher quality and better surface finish, thereby resolving the contradiction between chip evacuation and thread quality
3Force
If long chips are produced, then cutting force is reduced, but chip jamming and tool damage increase
Solution Approach 1:
The patent uses selective chip breaking on specific flutes to break chips into manageable segments. This prevents long chips from causing jamming and tool damage while still allowing sufficient cutting force to be applied. The chip breakers create localized chip curling and breaking zones that eliminate the harmful effects of long chips without requiring reduction of cutting force
Data Source
Figure 1~3c
Figure 4~6d
Figure 7
AI summary
The invention relates to a thread cutting tap (1, 10) having an axial extension along a longitudinal axis (C) thereof from a front end (2) of the thread cutting tap to a rear end (3) of the thread cutting tap, wherein the thread cutting tap comprises a thread cutting portion (4) extending along the longitudinal axis (C) over at least a part of the axial extension of the thread cutting tap, and wherein the thread cutting portion (4) comprises a plurality of lands including a first land (21), a second land (22), and a third land (23), separated from each other by a corresponding number of associated flutes, including a first flute (31), a second flute (32), and a third flute (33). Each of the lands includes a plurality of thread cutting teeth and each of the flutes includes a rake face (51, 52, 53), wherein the first flute (31) comprises a first chip breaking feature (41) that extends, in the direction of extension of the first flute, a first distance (d1) on the rake face (51) of the first flute. At least one of the second flute (32) and the third flute (33) lacks a chip breaking feature. The invention also relates to a method for manufacturing a thread cutting tap.