Welding Device With Pointed Stamping Heads For High Cycle Rate
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Solution Overview
Problem
Existing methods for low-impedance welding of sheet metal with a high number of cycles require additional effort for forming contact points, which is not independent of the contact pressure needed for reliable welding current transmission.
Innovation Solution
A welding device with independently acting embossing heads and force measuring sensors allows for preheating and precise control of welding current, enabling reliable welding independent of electrode contact pressure, using adjustable prestressing elements and force measurement for optimal contact and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional effort is spent on forming contact points (graining, embossing, milling), then reliable welding current transmission is improved, but device complexity and manufacturing effort increase
Solution Approach 1:
The patent applies preliminary action by forming pointed extensions (graining, embossing, milling) on the metal sheets before the welding process. This pre-prepared surface geometry ensures that when the sheets are pressed together, the pointed extensions automatically create optimal contact points for current transmission without requiring additional complex device components.
Solution Approach 2:
The metal sheets themselves serve the dual function of being the workpiece and providing the contact point geometry through their surface features. The pointed extensions on the sheets create their own optimal contact conditions without requiring external devices to form them, thus the workpiece serves its own preparation needs.
2Reliability
If contact pressure between electrodes and sheets is increased, then welding current transmission is improved, but the decorative coating may be damaged
Solution Approach 1:
The patent applies local quality by concentrating the welding current and pressure only at the pointed extension contact points rather than distributing it across the entire sheet surface. This localized concentration ensures reliable current transmission through the metal while the decorative coating on the broader sheet areas remains undamaged.
Solution Approach 2:
The pointed extensions are pre-formed on the metal sheets to create optimal contact geometry before welding. This preliminary shaping ensures that when pressure is applied, the force is automatically concentrated at the pointed tips, achieving reliable electrical contact without requiring excessive overall pressure that would damage the decorative coating.
3Productivity
If high welding current is used, then welding speed is improved, but electrode coating and material sticking occur
Solution Approach 1:
The welding current is concentrated locally at the pointed extension contact points, creating intense heating only where needed for welding. This localized current concentration achieves effective welding at lower overall current levels, preventing the electrode coating damage and material sticking that would occur with high distributed current.
Solution Approach 2:
The patent employs impulse current with periodic on/off cycles. This periodic action allows brief high-current pulses for welding at the contact points, followed by off-periods that prevent excessive heat accumulation and material sticking, thereby maintaining productivity while avoiding harmful effects.
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 achieves a high cycle rate of at least 1200 welding processes per hour with low welding current levels, preventing electrode coating and ensuring reliable welds without material sticking, and allows for independent adjustment of embossing head pressure for various material pairings.
Implementation Method 1
a preheating current, which is first passed through the (upper) sheet to be welded, are heated to such an extent that this melts (or destroys) the inner coating of the decorative sheet
Implementation Method 2
a welding current with optimal welding data that excludes damage to the decorative layer is conducted via the contact point, welding the metal sheets
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
A device and method for the low-resistance welding of metal sheets with a high cycle rate, having the following features: a) a U-shaped main body (1), in the two horizontally mounted limbs of which there are arranged a lower stroke drive element (2) and an upper stroke drive element (7) which are situated opposite one another, wherein the lower stroke drive element (2) is followed in the direction of the action of force by a lower electrode holding device (3) and the upper stroke drive element (7) is followed in the direction of the action of force by an upper electrode holding device (6), b) a lower welding electrode (11) which is held by the lower electrode holding device (3) and an upper welding electrode (5) which is held by the upper electrode holding device (6), wherein the lower welding electrode (11) bears an in each case centrally arranged lower stamping head (10) which tapers to a point, and the upper welding electrode (5) bears an upper stamping head (8), c) a joining partner feed device (4) which conveys the joining partners (9) for welding into the intermediate space between the two stamping heads (10, 8), d) a current source which is adapted to the joining partners (9) and which provides the welding current.