Polygonal Stud Welding Head for Thin Sheet Burn-Through Prevention
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Solution Overview
Problem
The challenge in stud welding is to effectively secure thin body sheets without causing 'burn-through' and to ensure the strength of the welded joint, particularly in vehicle technology, where existing solutions require high energy input and result in costly rework if defects occur.
Innovation Solution
A stud with a polygonal outer circumference and an annular section designed for stud welding, allowing for a test torque to be applied, which reduces energy input during welding and enables easy verification of joint strength, thereby preventing burn-through and minimizing rework.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conically tapering welding surface is used on studs, then the stud can be welded to body sheets, but a relatively high input of energy is required which may lead to burn-through of thin body sheets
Solution Approach 1:
The invention changes the geometric parameters of the welding surface from a conical taper to a substantially planar surface with specific dimensions (diameter 0.8-1.2 times the stud shank diameter, distance from flange 0.5-1.5 times the shank diameter). This parameter optimization allows for reduced energy input while maintaining reliable welded joints on thin body sheets, preventing burn-through while ensuring joint strength.
2Reliability
If a stud with uniform outside diameter head section and polygonal flange is used, then test torque can be applied to verify joint strength, but the stud design becomes more complex
Solution Approach 1:
The head section of the stud is designed with a uniform outside diameter and a polygonal outer circumference that serves multiple functions: it provides a standardized geometry for welding, enables application of test torque to verify joint strength, and allows for identification of the welding side. This multi-functionality reduces the need for separate verification components while maintaining reliability.
Solution Approach 2:
The polygonal shape of the flange outer circumference introduces intentional asymmetry that enables torque application and verification. The non-circular geometry provides distinct sides for welding and testing, allowing for simple torque verification procedures without adding complex verification mechanisms.
3Weight of moving object
If studs are welded onto thin body sheets to reduce vehicle weight, then weight reduction is achieved, but the welding becomes difficult and expensive rework is necessary if defects occur
Solution Approach 1:
The invention enables preliminary verification of the welded joint by applying test torque to the polygonal flange before final assembly. This preliminary action allows defective joints to be detected and corrected during the body-in-white phase when rework is inexpensive, rather than discovering defects later during assembly when rework would be costly. The standardized head geometry facilitates this preliminary testing.
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
The solution enables cost-effective welding of thin sheets with reduced risk of burn-through and allows for timely detection and repair of defective joints during the body-in-white phase, avoiding expensive rework in the assembly phase.
Implementation Method 1
The welding of studs onto body sheets that are becoming increasingly thinner turns out to be difficult. As a rule, the studs have a conically tapering welding surface. In order to fuse this surface during the stud welding, a relatively high input of energy is required.
Implementation Method 2
In order to fuse this surface during the stud welding, a relatively high input of energy is required. This may lead to 'burn-through' of the body sheet.
Data Source
Figure 1~3
AI summary
The invention relates to a stud (10) for stud welding, having a shank (12), having an axially adjoining flange (14) which projects radially relative to the shank (12) and whose outer circumference is of polygonal design in order to be able to apply a test torque (T) to the stud (10) by means of a tool (40), and having an annular section (16) which axially adjoins the flange (14) and whose front, radially extending annular surface (19) is designed as a welding surface which is to be welded to a workpiece (32), wherein the annular section (16) directly adjoins the flange (14), and the annular section (16) and the flange (14) form a head section (20) which has a uniform outside diameter (D) throughout, and wherein the polygonal shape (22) of the flange (14) extends over the annular section (16) up to its front annular surface (19).