Laser Cladding Head Mirror Protection for Confined-Space Repair
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Solution Overview
Problem
Conventional laser cladding heads are unsuitable for applications in confined or obstructed spaces due to their length, which restricts access and precision in welding or repair operations, especially in areas like pipes where obstructions block access.
Innovation Solution
A laser cladding system with a long focal length focal array and an indexable nonfocal turning mirror that redirects the laser beam transversely, combined with a borescope for high-resolution imaging and a gas system to protect the mirror and prevent oxidation, allowing for precise welding in narrow or obstructed areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional laser cladding heads are used, then welding precision can be maintained, but the head length becomes too long to access confined spaces
Solution Approach 1:
The laser cladding head is segmented into separate functional components: a long focal length focal array positioned away from the target area, and a compact working end with the turning mirror and powder delivery system. This segmentation allows the focal array to be positioned proximally while maintaining beam focus at the distal target point, effectively reducing the functional length requirement of the cladding head.
Solution Approach 2:
The system uses a turning mirror to redirect the laser beam at an angle (non-axial direction) to reach the target point. This dimensional change in beam delivery allows the cladding head to access confined spaces and oblique surfaces that would be inaccessible to conventional axial beam delivery systems, effectively reducing the required insertion depth.
2Manufacturing precision
If the focal length is increased to improve working distance tolerance, then the cladding head becomes longer and harder to maneuver
Solution Approach 1:
The optical system is segmented with the focal array positioned separately from the target area. The long focal length focal array is located in the proximal portion of the cladding head, while the target point is in the distal portion. This spatial segmentation allows the system to achieve long focal length benefits (increased working distance tolerance) without requiring the entire cladding head to be excessively long, as the beam is focused at a distance from the mirror assembly.
3Adaptability or versatility
If a turning mirror is used to redirect the beam, then access to oblique surfaces is improved, but the mirror is exposed to debris and oxidation
Solution Approach 1:
A protective gas flow system acts as an intermediary between the weld zone debris and the turning mirror. The gas flow deflects debris and spatter away from the mirror surface, preventing contamination and oxidation. This intermediary protective mechanism allows the turning mirror to maintain its reflective properties and durability while still enabling access to oblique surfaces through beam redirection.
Solution Approach 2:
The system uses an inert gas atmosphere to protect the turning mirror from oxidation and contamination. The gas flow creates a protective environment around the mirror, preventing harmful chemical reactions and physical contamination from weld debris, thereby extending mirror life while maintaining the ability to redirect beams to oblique surfaces.
4Length of moving object
If the focal array is positioned close to the target area, then the head can be shorter, but tolerance to working distance variations is reduced
Solution Approach 1:
The system segments the optical path into a proximal focal array region and a distal target region. The long focal length focal array is positioned in the proximal portion, creating a extended optical path that achieves working distance tolerance benefits without requiring the physical cladding head to be excessively long. The beam travels through the segmented optical path, maintaining focus precision while allowing for working distance variations.
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
Enables high-precision welding with increased tolerance to variations in working distance, allowing the system to operate effectively in confined spaces by maintaining beam focus and protecting critical components from debris and oxidation, thus extending the life of the turning mirror and reducing operational costs.
Implementation Method 1
a long focal length focal array at a proximal end to focus a laser beam along a primary axis extending between proximal and distal ends of the cladding head
Implementation Method 2
an indexable nonfocal turning mirror at a distal end to redirect the laser beam towards a target point a working distance away from the primary axis
Implementation Method 3
A gas system supplies a high speed gas flow to deflect debris and spatter away from the turning mirror
Implementation Method 4
a laser beam (typically received via an optical fiber line) creates a small melt pool on the surface of the workpiece
Implementation Method 5
Laser powder deposition is commonly used in manufacture and repair methods... Laser cladding heads spray pulverant towards an area to be joined or repaired, while a laser beam creates a small melt pool on the surface of the workpiece. This melt pool captures and incorporates some of the powder.
Data Source
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AI summary
A laser cladding system (10) comprises a cladding head (12) and a gas system (50). The cladding head (12) extends along a primary axis (AP), and comprises a mirror (30) and a powder nozzle (34) both situated at a distal end (22) of the head (40). The powder nozzle (34) directs weld material at a target point (PT), and the mirror (30) directs a beam (28) of collimated light at the target point (PT). The gas system (50) comprises a high-speed gas nozzle (304) and a gas knife (310). The high-speed gas nozzle (304) produces a gas sheath (302) coaxial with the beam (28) in a region between the mirror (30) and target point (PT), shielding the mirror (30) from debris and backspatter. The gas knife (310) redirects the gas sheath (302) away from the target point (PT) and redirects debris and molten backspatter away from an interior of the laser cladding head (12).