Thread-Forming Screw With Welded Cutting Elements
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Solution Overview
Problem
Existing methods for manufacturing thread-forming screws with welded-on cutting elements require lengthy processes that soften the base material, leading to heat-induced structural changes, potential cracks, and decreased corrosion resistance.
Innovation Solution
A method involving forming a thread on a shank, stamping recesses into it, and welding compact cutting elements made of harder material into these recesses, which are designed to match the thread's extent, thereby minimizing base material melting and preserving corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base material is softened to allow cutting elements to be pressed into the thread, then the cutting elements can be sufficiently anchored in the thread, but the screw material is locally brought to high heat which alters the structure of the base material and may lead to the formation of cracks
Solution Approach 1:
The patent applies preliminary action by pre-forming recesses or indentations in the thread before welding the cutting elements. These recesses are created while the material is in its original state, not softened. The cutting elements are then welded into these pre-formed recesses, eliminating the need to press them into softened material and avoiding the harmful heat effects associated with excessive softening.
Solution Approach 2:
The patent applies local quality by creating localized recesses only in the specific regions where cutting elements need to be anchored, rather than softening the entire thread. This localized approach allows the cutting elements to be securely positioned without subjecting the entire base material to harmful heat treatment, preserving the structural integrity of the surrounding material.
2Reliability
If the base material is softened to allow cutting elements to be pressed into the thread, then the cutting elements can be sufficiently anchored in the thread, but the corrosion resistance of the shank may decrease region-wise due to the action of the heat
Solution Approach 1:
The recesses are pre-formed in the thread before the welding process, allowing cutting elements to be positioned without requiring extensive softening of the base material. This preliminary formation of recesses minimizes the thermal affect zone during welding, thereby preserving the corrosion-resistant properties of the shank material in the surrounding regions.
3Strength
If cutting elements are welded on the thread, then the hardness of cutting elements is greater than the hardness of the screw, but the base material must be sufficiently softened which requires long process time
Solution Approach 1:
The recesses are formed in advance before the welding process, eliminating the need for time-consuming softening operations. The cutting elements are then directly welded into these pre-formed recesses, significantly reducing the overall process time while maintaining the high hardness of the cutting elements.
4Reliability
If the base material is brought to high heat during welding, then cutting elements can be anchored, but the structure of the base material is altered
Solution Approach 1:
The patent creates localized recesses only in the specific areas where cutting elements need to be anchored, rather than heating and softening the entire thread. This localized approach confines the thermal effects to minimal regions, preserving the structural composition and properties of the surrounding base material.
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 a securely anchored cutting element with reduced material wear and preserved corrosion resistance, enabling higher load ratings and cost-effective manufacturing with improved thread-forming performance.
Implementation Method 1
a plurality of recesses or indentations is stamped into the thread, wherein the material of the screw is hardened in this region, at least in part
Implementation Method 2
a plurality of compact cutting elements is welded into the previously generated recesses in the thread
Data Source
AI summary
A method for manufacturing a thread-forming screw having a shank and a thread formed in one piece with the shank and region-wise circumferentially arranged on the shank, is disclosed. After the formation of the thread on the shank, a plurality of recesses is subsequently stamped into the thread. Then, a plurality of compact cutting elements is welded into the recesses in the thread, where the cutting elements are made of a hard material and have a hardness greater than the hardness of the thread. Additionally, a stamping device for carrying out the method is also disclosed.