Thread Forming Die Curved Elements
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Solution Overview
Problem
Existing thread roll forming dies for male fasteners assume a constant blank diameter, leading to misalignment and deformation of threads due to the increasing rolling diameter during the forming process, resulting in non-uniform threads and premature wear.
Innovation Solution
The thread forming elements on the dies are longitudinally spaced based on the increasing diameter of the blank, with the transverse pitch adjusted to reflect the changing rolling diameter, allowing the thread form to follow a curved path rather than a straight line, ensuring proper alignment and reduced wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If straight-line thread forms are used on the dies, then the manufacturing process is simple and easy to implement, but thread deformation occurs and manufacturing precision deteriorates
Solution Approach 1:
The patent applies curvature by transitioning from straight-line thread forms to curved/threaded paths on the die surfaces. The thread forms now follow a curved trajectory that accounts for the increasing rolling diameter, ensuring proper alignment and uniform thread formation throughout the rolling process.
Solution Approach 2:
The patent changes the geometric parameters of the thread forms on the dies. Instead of constant straight-line paths, the thread forms now have variable parameters (curved paths) that adapt to the changing rolling diameter, maintaining alignment and precision throughout the forming process.
2Reliability
If the blank diameter is assumed constant during rolling, then the thread form alignment is maintained, but thread deformation occurs due to the actual increasing diameter
Solution Approach 1:
The patent acknowledges and compensates for the changing parameter (diameter) during the rolling process. The thread forms on the dies are designed with curved paths that account for the increasing diameter, maintaining proper alignment and preventing deformation throughout the forming process.
3Shape
If multiple revolutions are used to form deeper threads, then thread depth is achieved, but manufacturing time increases and die wear increases
Solution Approach 1:
The curved thread forms on the dies enable more efficient material deformation by following the actual rolling path. This improves the effectiveness of each revolution, allowing deeper threads to be formed in fewer passes while reducing die wear through better alignment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in better thread formation quality and extended die life by maintaining proper alignment during the rolling process, reducing heat generation and improving performance.
Implementation Method 1
Multiple revolutions of the blank are employed to progressively deform the blank material to fully form the thread crests and roots
Implementation Method 2
The movement of the moveable die with respect to the stationary die causes the screw blank to rotate and advance along the die surfaces
Data Source
AI summary
A die for roll forming threads on a cylindrical blank includes a planar die body having a longitudinally elongate working face of sufficient length for the blank to make multiple revolutions across the face. A plurality of thread forming elements on the face. The thread forming elements are spaced apart longitudinally of the die working face an ever increasing distance, based on the actual rolling diameter of the blank with the spacing between the thread forming elements at the start end equal to the diameter of the blank and the spacing between the thread forming elements at the finish end equal to eighty-five percent of the final diameter of the thread formed on the blank. The thread forming elements on the working face of the die are equally spaced apart in a direction perpendicular to the longitudinal extent of the working face.