Correlation-free measuring

A Game Changer for In-Line Measuring Technology

Correlation-free measurements will make it easier for the automotive industry to measure and manufacture parts with even greater efficiency.

OBERKOCHEN/Germany, 2017-05-09.

With correlation-free measurements, ZEISS is launching a new innovation that will enable the automotive industry to measure and manufacture parts with even greater efficiency. This technology marks a massive step forward on the path to the Smart Factory of tomorrow. At ZEISS, correlation-free measurements are considered a game changer because they will permanently alter in-line measuring technology and ultimately the world of manufacturing. This innovation will be presented at the Control trade fair in Stuttgart from 9-12 May 2017.

ZEISS developed correlation-free measuring to ensure that component dimensions are measured reliably in the production line, beginning with the very first part. With this system, companies must no longer subsequently measure their car body components on a highly precise coordinate measuring machine (CMM) at regular intervals, and then transfer the identified deviations between the in-line and CMM measurements to the in-line measuring systems as correction values. "Correlation-free measurements will provide an entirely new foundation for in-line measuring technology and boost manufacturing efficiency," says Dr. Kai-Udo Modrich, Head of Carl Zeiss Automated Inspection. A quick look at the world of in-line technology below will provide a better understanding how automotive manufactures benefit from this new technology.

Dimensional accuracy – the be all and end all in manufacturing

Automotive manufacturers throughout the world monitor production using in-line measuring systems to meet their own high quality standards. These systems detect geometric deviations from defined characteristics and provide 100% inspection in the production cycle. The speed and precision at which the geometric characteristics are inspected depend primarily on the optical sensors used. For example, the ZEISS AIMax 3D sensor uses fringe projection to generate a point cloud in just a fraction of a second. By obtaining thick point clouds, multiple characteristics can be measured immediately with just a single capture thanks to ZEISS AIMax cloud. Moreover, even very small characteristics can be measured precisely and on different surfaces. As is typical with all in-line systems, a flexible robot arm moves this outstanding sensor to the corresponding characteristics on the individual car body components. This method ensures that the entire measuring system provides accurate results, making subsequent measurements unnecessary. With traditional in-line measuring systems, reference measurements are performed on artifacts for reliable repeat accuracy. Active compensation is necessary for the robot arm extension because of self-heating and changing ambient temperatures. As robot measurements typically have minimum absolute precision, the determined measurement values are usually offset by performing a comparison measurement on a CMM. The correlation is then checked using multiple measurements. The additional workload for the CMM in the measuring lab as well as the time required pose a challenge in the automotive industry, but correlation-free measurements will make this a thing of the past.

Reliability starting with the very first part

ZEISS developed correlation-free measuring to ensure that component dimensions are measured reliably, beginning with the very first part. This system uses standard cameras to detect the robots' deviation from their specified position resulting from temperature influences.
These cameras are installed above the in-line cell and track every movement of the ZEISS AIMax cloud sensor without any difficulty.
There are markers on the robot arms and on the base of the in-line cell so that the system can determine the absolute spatial position of the sensors.
Thanks to this information and, most importantly, intelligent algorithms, the software developed by ZEISS detects deviations from the standard state and immediately filters these out.

With this system, companies must no longer subsequently measure their car body components on a CMM at regular intervals, and then transfer the identified discrepancies between the in-line and CMM measurements to the in-line measuring systems as correction values. For Modrich, it is clear how users will benefit: "Now manufacturers can be sure that the measured values are correct, beginning with the very first part. Having spoken with many different customers, I know that car makers have been eagerly awaiting this technology."

"Companies significantly expedite the ramp-up times for manufacturing new models and achieve the desired move rate more quickly. And that means real savings," says Modrich. "Since the system already delivers reliable data beginning with the first part, it lays the foundation for implementing a closed production loop between the in-line measuring station and the welding robot, to take just one example."

Correlation-free measurements enable automotive manufacturers to make measuring and production more efficient.

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Press contact

Bernd Balle
Industrial Metrology
Phone: +49 7364 20-8148
bernd .balle @zeiss .com


ZEISS is an internationally leading technology enterprise operating in the fields of optics and optoelectronics. The ZEISS Group develops, produces and distributes measuring technology, microscopes, medical technology, eyeglass lenses, camera and cinema lenses, binoculars and semiconductor manufacturing equipment. With its solutions, the company constantly advances the world of optics and helps shape technological progress. ZEISS is divided up into the four segments Research & Quality Technology, Medical Technology, Vision Care/Consumer Products and Semiconductor Manufacturing Technology. The ZEISS Group is represented in more than 40 countries and has over 50 sales and service locations, more than 30 manufacturing sites and about 25 research and development centers around the globe.

In fiscal year 2015/16 the company generated revenue approximating €4.9 billion with over 25,000 employees. Founded in 1846 in Jena, the company is headquartered in Oberkochen, Germany. Carl Zeiss AG is the strategic management holding company that manages the ZEISS Group. The company is wholly owned by the Carl Zeiss Stiftung (Carl Zeiss Foundation).

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Industrial Metrology

The Industrial Metrology business group is a leading manufacturer of multidimensional metrology solutions. These include coordinate measuring machines, optical and multisensor systems, and metrology software for the automotive, aircraft, mechanical engineering, plastics and medical technology industries. Innovative technologies such as 3D X-ray metrology for quality inspection round off the product portfolio. The business group additionally offers a broad global spectrum of customer services with measuring houses and competence centers close to its customers. The Industrial Metrology business group is headquartered in Oberkochen. Production and development sites outside Germany are located in Minneapolis in the USA, Shanghai, China and Bangalore, India. The business group is allocated to the Research & Quality Technology segment. Around 6,100 employees work for the segment, generating revenue totaling €1.5 billion in fiscal year 2015/16.

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