Through-the-Lens Laser Marking for Large Workpiece Alignment
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Solution Overview
Problem
Existing laser marking systems struggle to consistently mark large workpieces without the need for specialized fixtures, as they often rely on cameras with limited fields of view, leading to alignment issues and increased operator training requirements.
Innovation Solution
The system employs a through-the-lens camera arrangement that captures multiple images from different locations within the marking field, stitching them together to create a composite image. This allows for the identification and marking of workpieces larger than the camera's field of view, regardless of their orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a camera with a limited field of view is used in the laser marking system, then the device complexity is reduced, but the manufacturing precision deteriorates due to alignment issues with large workpieces
Solution Approach 1:
The marking field is divided into multiple image tiles that are captured separately by the limited-field-of-view camera and then stitched together to form a composite image. This segmentation allows the camera to cover the entire large workpiece area without requiring a complex high-field-of-view camera system, while still achieving precise alignment through the composite image representation.
Solution Approach 2:
The system transitions from a single two-dimensional field of view to a composite representation that effectively creates an expanded viewing dimension. By capturing multiple tiles at different locations and stitching them, the system achieves coverage of a much larger area than any single camera view could provide, resolving the contradiction between camera simplicity and marking precision for large workpieces.
2Measurement precision
If multiple image tiles are captured and stitched to create a composite image, then the measurement precision is improved for large workpieces, but the loss of time increases due to additional capturing and processing steps
Solution Approach 1:
The system performs preliminary actions by capturing multiple image tiles and stitching them into a composite image during the setup phase. This preliminary composite image creation enables precise identification of workpiece location and orientation before marking begins, allowing for automated alignment calculations that reduce manual setup time and improve measurement precision for large workpieces.
3Device complexity
If the beam path of the image capture device passes through the same lens as the laser, then the device complexity is reduced, but the reliability deteriorates due to potential interference between laser and image paths
Solution Approach 1:
The system applies local quality by using a dichroic mirror that selectively reflects specific wavelengths. The mirror is designed to reflect visible light wavelengths (for image capture) while transmitting infrared wavelengths (for laser marking). This localized wavelength-specific property allows both the laser beam and image capture to share the same optical path without interference, maintaining both device simplicity and operational reliability.
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 enables efficient and accurate laser marking of large workpieces without the need for specialized fixtures, reducing job setup time and improving alignment precision.
Implementation Method 1
The laser may be configured to produce a laser beam at a frequency at which the dichroic mirror is substantially transparent
Implementation Method 2
a marking head including electromagnetic energy deflectors and at least one lens, a beam path of the laser and a beam path of the image capture device both passing through the at least one lens
Data Source
AI summary
A laser marking system comprises a laser, an image capture device, a marking head including electromagnetic energy deflectors and at least one lens, a beam path of the laser and a beam path of the image capture device both passing through the at least one lens, and a computer system operable to perform a method comprising capturing image tiles at each of multiple different locations with the image capture device, stitching the image tiles to produce a composite image of the marking field, identifying a location and orientation of an image of a workpiece within the composite image of the marking field, determining a location and orientation of a mark to be applied to the workpiece based on the location and orientation of the image of the workpiece within the composite image of the marking field, and applying the mark to the workpiece with the laser.