With the aim of increasing product and process quality, production processes are constantly changing. Time and cost pressures are driving production rates up, and rejects down. A great deal of energy is therefore devoted to automating control stages.
Without mechanical assistance, man is unable to achieve these objectives. With the increasing automation of quality assurance, necessary but time-consuming and costly laboratory tests can increasingly be replaced by product checks "directly on the line". In this way, modern camera technology keeps an eye on the objects to be inspected and their properties at virtually any time during production, without actively intervening in the process. Combined with image processing, the use of camera images offers many advantages and possibilities.
Optical measurement and control techniques" enable quality checks to be carried out very quickly, directly during the manufacturing process, and with absolutely no wear and tear. Replacing simple barcode scanners with industrial cameras makes it possible not only to determine and evaluate code content, but also code quality, alignment, color, size, environment and so on. This not only extends the possibilities of inspection, but also its quality, while further simplifying the automation of quality assurance. Cameras can detect existing errors at an early stage, even before subsequent errors occur, which then require little or no correction. Yet what camera technology is capable of meeting the high demands of measurement and control technology, enabling machines to best support human beings, or even replace them, with their own decisions?
"3D image processing can significantly improve the flexibility and accuracy of measurement and control processes".says Dr. Martin Hennemann, Ensenso Product Manager at IDS Imaging Development Systems GmbH.
Today's 3D camera technology enables robots to analyze their environment and respond to events on their own. In addition to the dimensions and position of objects on the shop floor, this data enables precise conclusions to be drawn about deviations or imperfections in relation to reference objects. It is then possible to carry out checks on the line, indicating whether the "right" product components are being assembled.
Particularly in the automotive industry, where production involves a large number of variants, the potential for error is high. Customers can put together the car of their dreams. The selection includes different tires, engine versions, chassis or interior fittings. For this reason, production staff in particular benefit from automated systems, which trigger an alarm at the right moment, before a faulty or defective part is fitted. This reduces the need for subsequent checks, or worse, the risk of production downtime due to errors.
"The high degree of customization involved in vehicle configuration inevitably leads to a wide variety of variants, which are difficult to grasp and control without the help of camera technology."stresses Martin Hennemann.
In April 2018, at the "Control 2018" international quality assurance trade fair in Stuttgart, IDS demonstrated an example of "3D object verification". The demonstration system reconstructed objects with an Ensenso N35 3D camera and then performed a data comparison using Halcon image processing. The 3D data generated was also compared with a reference model to detect any discrepancies or imperfections. 3D image processing identifies anomalies or minor deviations in the test objects, which are not even visible to the human eye. According to IDS, the quality of manufactured objects can be significantly improved for subsequent process steps by high-precision scanning with Ensenso 3D cameras and subsequent image processing to check the objects.
For Martin Hennemann, 3D technology is a beneficial complement to 2D camera technology. Combined, these technologies enable us to solve ever more applications. Both technologies offer advantages for specific applications. 3D data can be used to determine shapes, surface structures or the position of objects in space. 2D data, on the other hand, precisely detects contours and colors. They are also capable of reading markings. In the IDS demonstration example, 3D data is also used to compare objects. Existing part codes can also contribute to identification. They are perfectly decoded with 2D camera images. Car manufacturers also use camera-based inspection techniques combining 3D and 2D technologies during final inspection, for example, to search for deviations on a body that has already been assembled, and to check or measure them precisely according to specifications.
In general, camera technology offers many possibilities for moving towards zero-defect production. To effectively limit production errors, each required control criterion can call on one or both technologies. Camera systems also support manual processes in manufacturing. They monitor manual sequences at workstations. Image analysis checks whether the correct parts have been entered, whether the required number of screws matches, or whether a part has been overlooked. A follow-up system gives an audible or visual warning on the monitors or by projection whether the work has been carried out correctly or incorrectly. This ensures quality control during the manufacturing process.
Camera and production technologies are constantly developing. But a new camera technology does not immediately replace an existing one. The young 3D technology, which has developed enormously in recent years, visualizes other characteristics of an object. It opens the way to new applications and complements, but does not replace, 2D camera technology. Cameras are also evolving from "simple" image providers to flexible, "intelligent" image processing solutions. Alongside 2D and 3D cameras, machine vision systems such as the IDS NXT platform, when effectively combining cameras, sensors, intelligence, communication and adaptability, also make a major contribution to error prevention in quality assurance. Today, as in the past, "perfect" production without rework or defects is an ideal that is impossible to achieve, even with a lot of money and the most modern technologies. However, the use of camera and analysis technology has become indispensable for all those who want to get as close as possible to the goal of zero-defect production.
Learn more: www.ids-imaging.com