Indexable Laser Cladding Head for Welding in Confined Spaces
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Solution Overview
Problem
Conventional laser cladding heads are unsuitable for applications in confined spaces due to their length and inability to access obstructed areas, limiting their use in welding within pipes or other narrow environments.
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 from debris, allowing precise welding in obstructed areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional laser cladding head is used, then the laser beam can be focused precisely on the target point, but the head is too long to access confined spaces and obstructed areas
Solution Approach 1:
The optical system is segmented into multiple components: a focal array with multiple focal points positioned at different distances from the turning mirror, allowing the laser beam to be focused precisely at various working distances without requiring a long head structure. The turning mirror acts as an intermediary that redirects the beam from these distributed focal points to the target.
Solution Approach 2:
A turning mirror is introduced as an intermediary optical element that redirects the laser beam from the focal array to the target point. This mediator allows the focal array to be positioned away from the target area, enabling access to confined spaces while maintaining precise beam focusing through the mirror's redirection capability.
2Ease of operation
If the turning mirror is positioned close to the target point to enable access to confined spaces, then the head can reach obstructed areas, but the mirror is exposed to debris and weld spatter that can damage it
Solution Approach 1:
The turning mirror is made rotatable about an axis, allowing it to be dynamically repositioned. When debris or spatter threatens to damage the mirror surface, the mirror can be rotated to expose a fresh, undamaged portion of its surface, thereby extending its operational life and maintaining reliability in harsh environments.
Solution Approach 2:
As the turning mirror rotates, previously exposed portions that have been damaged by debris or spatter are effectively discarded from the active beam path. The system recovers functionality by continuously presenting new, undamaged portions of the mirror surface to the laser beam, extending the component's service life.
3Reliability
If a long focal length focal array is used to increase tolerance to working distance variations, then the system can accommodate positioning variations, but the device complexity increases
Solution Approach 1:
The focal array is segmented into multiple discrete focal points positioned at different distances from the turning mirror. This segmentation allows the system to accommodate variations in working distance by selecting the appropriate focal point, providing tolerance to positioning variations without requiring a single complex adjustable mechanism.
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 in confined spaces with increased tolerance to variations in working distance and extended mirror life through indexing, reducing operational costs and maintaining weld quality.
Implementation Method 1
a focal array (26) at a proximal end (20) of the cladding head. The focal array focuses 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 (30) at a distal end (22) of the cladding head. The turning mirror redirects the laser beam towards a target point a working distance away from the primary axis
Implementation Method 3
a laser beam (28) creates a small melt pool on the surface of the workpiece
Implementation Method 4
Lasers in such systems can be tightly focused, enabling precise deposition of powder in a target area
Implementation Method 5
additional inert gas is often directed substantially along the same axis to the molten puddle at the target point to protect from oxidation
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A laser cladding head (12) comprises a protective housing (18), a focal array (26), a turning mirror (36), and a powder nozzle (34). The housing (18) extends along a primary axis (AP) from a proximal end (20) to a distal end (22). The focal array (26) is situated at the proximal end (20) and oriented to receive and focus collimated light (28) in a beam (28) directed substantially along the primary axis (Ap). The turning mirror (30) is situated at the distal end (22) and disposed to redirect the beam (28) in an emission direction, towards a target point (PT) separated from the turning mirror (30) by a working distance (DT) of at most a tenth the focal length. The turning mirror (30) is a nonfocal reflective surface indexable to alter an impingement location (PI) of the beam (28) on the turning mirror (30). The powder nozzle (34) is situated at the distal end (22) and receives and directs weld material towards the target point (PT) for melting.