In-line inspection for Industry 4.0
Mapvision RAIC technology: Industry 4.0 compatible in-line inspection
Mass production is changing. Efficiency and precision are moving towards zero defect manufacturing, and new digital technologies enable a paradigm shift that will be changing the way people see production quality and precision.
The digitalization of inspection processes is irreversible. Its development follows a path familiar to most industries. Initially, a process is entirely mechanical, and step by step, it slowly becomes fully digital. For in-line measurement, this has meant evolution from mechanical gauges and mechanical coordinate measuring machines (CMMs) to semi-digital systems like digitally-controlled CMMs and optical robotic measurement systems. The final stage of evolution will be an entirely digital process, like photogrammetric multi-camera measurement.
Flexible automatic production is a clear product of the fourth industrial revolution, with the potential to substantially increase the efficiency of production processes. However, truly realizing the revolution requires efficient and flexible support systems, like fully digital and automatic 100% in-line inspection methods.
Until now, the available measurement technologies for car chassis and body component production have not been able to produce fully reliable 100% inspection data in real time. Optical robot measurement systems (RMS) suffer from the fact that the positioning of the sensors is dependent on mechanical movement and the accuracy of the robots. In this environment, it has been necessary to base quality assurance on sampling and statistical methods, and the adjustment of processes on CMM data.
The CMM measurement data itself is highly accurate, but due to the slow speed of measurement, the data is only available after a delay and the number of measured parts is limited by the time available at the CMM. Thus, process adjustments have been slow, and they have been based on small samples of production. It is clear that this is not optimal. Instantly available, reliable and complete measurement data will significantly speed up line adjustment and, in fact, will simply make it possible to adjust lines better. New, fully-digital measurement technologies can provide the necessary performance.
The missing piece of the puzzle
Mapvision’s unique measurement technology is part of Industry 4.0. A fast and accurate digital measurement technology, it can monitor dimensional quality as well as component presence in real time, without disrupting the production flow.
The RAIC technology created by Mapvision is based on short-range multi-camera photogrammetry combined with image recognition. The system uses a set of static cameras that are calibrated into one linear orthogonal coordinate system. Each camera has a wide-angle view, and it can measure whatever features are within shot. In other words, unlike most similar technologies, the cameras are not dedicated to any specific measurement features.
Its performance and unique capabilities are due to the fact that the Mapvision RAIC measurement process is fully digital. Most other similar technologies involve mechanical movement while taking measurements, but Mapvision measurement does not.
Benefits of digital multi-camera inspection
A fully-digital process is faster and more accurate than any mechanical or semi-mechanical inspection method. Once the measured part has been put in place, nothing in the system moves. The Mapvision inspection process involves two stages: image taking and result calculation. Once pictures have been taken, the part can be removed. Results are calculated while the part is being lifted off the fixture.
Mapvision Quality Gate can deliver 3D measurement data of up to several hundred features, within a typical line cycle time of 30 seconds.
System calibration puts the cameras into one linear orthogonal coordinate system. For parts like subframes and cross car beams, the system reaches an average CMM correlation of 0.1 mm and repeatability of 0.02 mm. These values apply when the data is compared to normal, good production parts.
The system continuously monitors its own measurement quality, and sends an alert if problems are detected. This means you can trust the results, and you can use them to adjust your line without verifying them each time with your CMM.
One camera is not critical. Should a camera fail, the effects on the measurement are generally minimal.
As there are no moving parts, calibration does not change over time. Only incidental camera movement might create a need for system re-calibration. Normally, the calibration is checked once a year during the annual system maintenance.
The system can also use its machine vision capabilities to automatically detect the presence of components like weld studs and clip nuts. This needs only an additional software function, with no changes in hardware and almost no detectable extra inspection time. Automatic digital presence check control is more reliable and cost-effective than any manual inspection by an operator.
The best evidence of clear benefits is the fact that Mapvision’s first customers continue to invest in the technology, many of them integrating a Quality Gate system into every new production line. OEMs can clearly see the importance of 100% supplier quality. Disruptions caused by the supply of defective components need to be eliminated.
The 100% in-line inspection process is a central tool in making this happen. For the supplier, 100% delivery quality means less cost, less troubleshooting and a better supplier reputation. This naturally brings them higher profits.
The reduction of waste is a logical consequence of a 100% in-line inspection system. However, the potential for saving goes way beyond this. Such a system allows further optimization of the process, so that quality can still be increased, even while reducing costs. If everything is measured, the process doesn’t need to be fine-tuned for statistical process control (SPC). This saves time and money.
Impact on the industry
Paradigm-shifting digital technologies will complete migration into the next industrial era. This will make non-disruptive accuracy ubiquitous. Absolute accuracy will become the standard, tolerance for defectiveness will decrease, disruption within the mass production process will drop to a minimum, and unrestrained agility and adaptability will become the norm. The quality of products will further improve and the productivity and profitability of mass production facilities will continue to rise.