Rolling Die Slope Variation for Screw Thread Quality
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Solution Overview
Problem
Conventional screw manufacturing methods require a specific rolling diameter for the blank, limiting flexibility and increasing costs when producing screws with different thread forms or head sections, as they often necessitate blanks with variable diameters.
Innovation Solution
A rolling die with varying depression slopes between its ends, allowing for a flexible selection of blank diameter and depression slope variation to accommodate different screw designs, including those with variable thread pitches, thereby enabling the use of a larger blank diameter and compensating for material volume defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a specific rolling diameter dw0 is selected to match the thread form requirements, then the thread quality is improved, but the flexibility in blank selection is reduced and manufacturing costs increase
Solution Approach 1:
The patent changes the geometric parameters of the rolling die by varying the slope of depression center lines between different regions (first end vs second end). This allows the rolling process to accommodate blanks with different diameters while maintaining consistent thread quality, as the slope variation compensates for differences in blank diameter relative to the required cylindrical substitute diameter dG0.
2Ease of manufacture
If a larger blank diameter is used to accommodate screw head formation, then the ease of manufacture is improved, but the thread formation quality deteriorates due to excessive material volume
Solution Approach 1:
The patent applies local quality by creating different depression slopes in different regions of the rolling die. The first end has a slope suitable for thread formation from larger diameter blanks, while the second end has a different slope that ensures proper thread quality. This regional differentiation allows the same blank to be processed successfully for both head formation and thread formation.
3Device complexity
If conventional rolling dies with parallel depression center lines are used, then the device complexity is reduced, but the adaptability to different screw designs is limited
Solution Approach 1:
The patent introduces dynamic characteristics into the rolling die design by varying the depression slopes along the rolling direction. Instead of a static, uniform slope throughout, the die features different slopes in different regions, allowing it to adapt to various blank diameters and screw designs while maintaining a relatively simple overall structure.
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 allows for the manufacture of screws with desired shapes and thread forms using larger blank diameters, reducing production costs and enabling the formation of screw heads and threads with consistent or variable thread pitches, while maintaining thread quality and reducing material usage.
Implementation Method 1
a blank is rolled between two rolling dies for the purpose of forming the screw thread... transverse pressure a flow in longitudinal direction of the thread occurs
Data Source
AI summary
A method for manufacturing a screw is disclosed where a blank is rolled between two rolling dies. In each rolling die a rolling profile has been formed that comprises a host of elongated depressions. The rolling die has a first and a second end which are spaced apart from each other in the direction of rolling. During rolling, the blank is moved relative to the die from the first end in the direction of the second end. The mean pitch of the center lines of the depressions, which pitch is defined as the quotient of the changes in the positions of the center line in the direction across or parallel to the direction of rolling, in a region of the first end of the rolling die differs from the mean pitch in a region of the second end of the rolling die.