In the world of manufacturing, precision is paramount. Any deviation from exact specifications can lead to wasted materials, increased scrap, and ultimately, decreased profitability. In this landscape, automated vision alignment capabilities are proving to be game-changers. While machine vision has been around for decades, manufacturers have just begun to recognize its value in sheet processing applications. Machine vision eliminates errors caused by operator error or variations in incoming materials enabling manufactures to compete at the highest levels with unprecedented precision, consistency and productivity.
As an advanced laser cutting solution, the LaserCube is equipped with a high-resolution camera system and advanced vision registration software that allows users to take advantage of part alignment and high-accuracy cutting as soon as the system is installed.
High-Resolution Camera
The LaserCube’s advanced vision capabilities are supported by a high-resolution camera installed parallel but offset to the beam. Unlike alternative systems that focus a camera through the laser optics, the LaserCube's vision setup allows for higher magnification and a larger field of view. This means that even features on panels or parts that are less than ideally placed can be accurately located without operator intervention.
The offset between the laser beam and the camera is addressed through an automated beam-to-camera offset software routine. In this process, the laser marks a spot on a sample target, and the camera automatically locates and aligns to that spot. This automated calibration process is both speed and accurate.
Alignment Flexibility
The LaserCube vision system is not limited to aligning to panel edges – instead the camera can be taught with virtually any high contrast image to use each alignment point as a unique feature. These features could be a pre-existing alignment fiducial, the corner of a character on a printed nameplate, or any combination of other features. During the alignment process, the reference image is compared to the part image before the offset from nominal position is compared and corrected to ensure that the cutting path is properly aligned to the workpiece.
In addition to the alignment reference images, a unique starting point image can also be trained. This allows alignment to features across a long baseline, followed by alignment to the program start point for increased accuracy.
Implementation Options
Vision integration varies based on application needs and material consistency. In the most basic of implementations, for example, alignment to the incoming sheet will be performed using opposite corners of the workpiece and returning the sheet datum for final alignment of a process start point. This eliminates any errors in operator loading of the sheet.
A common two-step process is often used for tasks like cutting photo-etched parts, where initial alignment to the sheet is followed by alignment to the first part to correct for any offsets. Once aligned to the first part, the same correction is applied to subsequent parts in the array.
When processing stamped or punched parts, or where there may be other sources of inconsistency in input materials, there may be more variations that need to be corrected. In the case of parts like medical grade saw blades, where accuracy is critical, the machine can be configured for alignment not only to the whole sheet, but also to unique positions on every part of the sheet. The result is absolute alignment to the stamped features, resulting in output of parts meeting exacting critical tolerances necessary for medical instruments.
Correcting for Scaling Errors
LaserCube systems offer additional capability for correcting for scaling errors that may occur in silk screening or chemical etching processes. This capability allows both correction for orientation as well as scaling. This capability requires 4 target points in a rectangle on the sheet. These are often alignment fiducials dedicated solely for part alignment but may also be existing features where an existing rectangle exists on a printed part. This feature can also be particularly useful in cases where different scale parts are desired, without having to create unique drawing files for each part size.
