Sliding Pressing Pad for Consistent Laser Welding Force
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for laser welding of large-sized plastic workpieces face challenges in consistently applying a sufficient clamping force, particularly for complex geometries, as they require complicated fixtures or bulky mounting structures that can interfere with the welding process.
Innovation Solution
A laser welding apparatus featuring a pressing arm with a wear-resistant pressing pad that allows a sliding-contact movement, enabling consistent application of joining force along the welding direction while maintaining an optical path for the laser beam, and is adaptable for various shapes and sizes through a detachable and robot-mounted design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a roller element is used to apply pressing force during laser welding, then the joining force can be consistently applied at the welding location, but a complicated mounting structure is needed to rotationally mount the roller element without interfering with the laser beam transmission
Solution Approach 1:
The patent extracts the pressing function from a complex rotational mounting system and implements it through a simple linearly movable pressing arm that applies force directly at the welding location without requiring rotational mechanisms or complex laser beam path accommodations
Solution Approach 2:
Instead of using a roller element that rotates and requires complex mounting to accommodate the rotation, the patent inverts the approach by using a pressing arm that moves linearly in the welding direction, simplifying the mounting structure while maintaining consistent pressing force application
2Reliability
If a fixture with pressure block assembly is used to apply joining force, then force can be applied over the entire assembly of workpieces, but different fixtures must be produced for each different product and the joints in the pressure block assembly interrupt the through-groove producing discontinuities in the weld
Solution Approach 1:
The patent employs a dynamic pressing arm that moves linearly in the welding direction rather than a static pressure block assembly, allowing a single fixture design to accommodate various workpiece geometries while maintaining continuous pressing force application without interrupting the weld groove
Solution Approach 2:
The pressing arm design serves multiple functions: it applies joining force, moves with the welding process, and accommodates different workpiece geometries through linear movement, eliminating the need for product-specific fixtures while maintaining continuous weld groove integrity
3Ease of operation
If a pressing arm with sliding-contact movement is used, then the pressing arm can move smoothly along the workpieces during welding, but the pressing surface must be wear-resistant to maintain consistent contact
Solution Approach 1:
The pressing surface is constructed from composite or specially treated materials that combine low friction properties for smooth sliding movement with high wear resistance to maintain consistent contact pressure throughout the welding process
Solution Approach 2:
The pressing surface parameters (material composition, surface finish, hardness) are optimized to achieve the right balance between smooth sliding movement and wear resistance, ensuring consistent contact force application throughout the welding operation
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 solution ensures a reliable and consistent joining force is applied across complex geometries without interfering with the laser beam, facilitating high-quality welds in large-sized plastic workpieces by using a wear-resistant pressing arm that can move smoothly along the workpieces during welding.
Implementation Method 1
The laser beam passes through a first (e.g., top) workpiece, which is transparent to the laser radiation, and is absorbed at a surface of a second (e.g., bottom) workpiece that is in contact with the first workpiece. Heat is generated at the surface of the second workpiece when the laser radiation is absorbed
Implementation Method 2
Heat is generated at the surface of the second workpiece when the laser radiation is absorbed, and some of this generated heat is transferred to the surface of the first workpiece that is in close contact with the second workpiece under the applied clamping force. This heating causes the material at the surfaces of the first and second workpieces to melt
Data Source
AI summary
A pressing device for a laser welding apparatus includes an arm member with opposite mounting and pressing ends. A pressing pad at the pressing end has an opening for allowing a laser beam to irradiate a workpiece assembly that is being pressed by the pressing device. The mounting end has a mounting structure for detachably securing the pressing device to the laser welding apparatus. The arm member is shaped to position the opening at a known fixed distance from a laser source of the laser welding apparatus. The pressing pad has a pressing surface on a workpiece-facing side thereof for applying a joining force to the workpiece assembly at a welding location. At least one of the size, shape and smoothness of the pressing surface allows a sliding-contact movement of the pressing surface along a surface of the workpiece assembly during application of the pressing force.