3D Laser Scan of Key

Filed under: 2D Profile Scanner

Demonstrating the capabilities of the new AccuProfile 820 Laser Scanner at the recent Quality Expo (Chicago), operators scanned an individual car key to produce an elevation map.  The AP820 laser scanner emits a laser line onto

a surface or object.  The image of this line is viewed by a high-accuracy CCD array.  Height positions are calculated across this line and transmitted over an Ethernet line to a PC computer.  The scanner is moved relative to the key on a small stage.  The linear encoder position of the stage is tracked directly by the scanner head and included in the data stream.  For more information, contact Acuity.

          

Laser Profile Scanning of Valve Base

Filed under: 2D Profile Scanner

In this application, engineers tested the Acuity AP620-7 laser line sensor to make dimensional profiles of a small polymer part used in an industrial applications. Currently, the company uses calipers and comparators to measure this part. The area to be measured is a diameter at the circumferential “shoulder” formed by the floor of the part and an interior wall.  Proper detection of the joint between the 30° wall and the horizontal surface was very important.  Additionally, it was critical to align the laser line with the diameter of the circular part and not a chord.  Any misalignment would result in a shorter diameter measurement.  Engineers suggested scanning the part as it passed beneath the scan line and then capturing several cross-sectional frames.  Software algorithms could be used to determine the maximum dimension of all collected and this number would be the diameter.

The size and shape of the part presented several challenges for using a line sensor.  The small part had rather tiny features and that is why engineers chose the most accurate model of Acuity laser line sensor because it could resolve the tiny features of the part.  That the area of interest was located within the cup-shaped part also presented challenges for applying the line sensor which relies on triangulation measurement principles.  Although it was simple to project the laser line across the target, the height of the part’s walls would block the view by the detector.  This is why simple laser triangulation sensors can not be used to measure down narrow bore holes, tubes, etc.  The laser may reach the target, but the detector can’t see because the height of the walls occlude its view.  To overcome this occlusion, the laser line sensor was deliberately tilted so that there was an unobstructed path for both the emitted and reflected beams.

The engineers concluded that the Acuity line sensor was a viable sensor solution for measuring such an intricate part.  For more information, please contact Acuity.

          

Welded Pipe Manufacturer uses Laser Scanners

Filed under: 2D Profile Scanner

A global manufacturer of steel pipes, tubes and rods maintains plants around the world that use the latest in factory automation technology.  Engineers from a plant in Brazil wish to improve the fabrication processes of welded steel pipe that is used in the oil and gas indstry.  Their product is formed in a multi-step bending process to steel sheet stock.

In the first step of the pipe fabrication process, a large, 12-m long carbon steel sheet is fed into a press which bends both edges with a slight radius of curvature.  Precision molds sandwich the material at high pressure to introduce the appropriate bend.  The system bends 3-m sections of steel at a time and a conveyor advances the material through the process until the full length of sheet has been bent.  The edge bend introduces a curve approximately 40 mm from the edge, leaving a straight tail at the very edge.

In subsequent steps, the steel sheet is further formed into a tube by using other presses.  Only at the end, the round structure is completed by welding the original edges.  The initial edge bend is critical to final gap alignment for successful welding and proper pipe dimensions and straightness.

The prior method for measuring / verifying the dimensions of the steel sheet edge was manual in nature.  Line workers would use a combination of templates, “feeler gages” and a ruler to verify the radius of the bend in the metal as well as the length of the straight tail between the end of the bend and the edge of the sheet.  Certainly, this method was operator dependent and subject to great variability and innaccuracy.  Over time, the template becomes deformed and worn and defeats the purpose for its initial use.

Replacing the manual verification methods was the implementation of non-contact scanning technology.  A 2D profile-scanning laser is installed aboave the edge and projects a wide laser line across the steel surface.  As the material passes beneath the scanner, it’s dimensional shape profile is captured by the sensor’s CMOS detector array.  This X Z position information is transmitted via Ehternet interface to a PC computer that hosts measurement algorithms (software) which automatically analyzes the high-speed data and calculates the radius of curvature and the length of the straigh tail of steel sheet edge.  At full speed, the laser scanner captures up to 250 profiles per second.

Integrators will install pairs of laser scanners along each edge to measure the desired dimensional information and to track the edge positions to ensure that the sheet is centered along the fabrication process.  Because the scanner captures both depth position and field of view, the representation of the profile is not susceptible to slight material vibrations as it is conveyed through the process by the roller bed.  The video below illustrates the entire process and the implementation of the AccuProfile Scanners in this application.  Contact Acuity with questions.