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Automated Robotic Part Spraying Inside Optical Metrology Cell

For the entire quality assurance process in optical metrology to proceed quickly, not only the pure measurement process but also the upstream and downstream steps must be optimised and ideally automated.

The preparation of the parts is one of the unpleasant but at the same time essential steps for a smooth measurement process. In particular, transparent and reflective surfaces require thorough preparatory work, since they cannot or can only be captured with difficulty by optical measuring equipment. The problem with transparent parts is that the scanner light is not reflected by the component surface, but rather passes through it. This means that the structure cannot be captured. It is similarly difficult with reflective surfaces that focus the light beam instead of diffusely reflecting it.

To be able to scan reflective and transparent parts, they need to be matted beforehand with a scanning spray. The spraying is very quick, but the subsequent cleaning of the parts and the surrounding area has always been problematic and time-consuming. To keep the cleaning effort within limits, the measuring objects were usually sprayed outside the measuring cell and then transported there.

It’s all now much easier and faster with the newly developed scanning spray from AESUB,  and the time-consuming transport between the spraying station and the measuring room is a thing of the past. Since the spray evaporates after a certain time, the parts can be sprayed in the measuring room itself. The spray is free of the pigments used in traditional sprays that are deposited in the scanning environment. The matting of the measuring parts is made even more efficient by automated spray robots.

Lightning-fast – Spray Robot Mattes Car Headlights in Seconds

Measurement service provider MQS (Germany) is breaking new ground with the AESUB Scan-Spray, which makes the entire measurement process even more efficient: transparent and reflective parts are automatically sprayed by a spray robot according to a preprogrammed routine.

To do this, the measuring part is positioned directly on the measuring machine.  Before the actual scanning, the spray robot sprays the predefined contours of the headlight. The spraying process is completed in less than 20 seconds and the part is covered with a thin and homogeneous matt layer. The thickness of the white layer is approx. 10 µm. It is dry to handle so that reference points can also be attached without any problems. This is followed by the actual scanning process, in which a second robot arm with a scanning system traces the same contours again. The component can then be removed immediately and the next part can be sprayed and scanned. Cleaning is not necessary as the layer sublimates on its own.

“The vanishing spray and robot allow us to better utilise our measuring capacities. The time saved is enormous, especially with repetitive scans of identical components,” says Andreas Zacherl, measurement engineer at MQS, describing the use of the AESUB Scanning Spray.

Matting Spray Without Pigments – Gentle on People and Environment

The AESUB spray is available in different versions. AESUB green in container form is used for automated spraying. It is fed through a hose to a nozzle on the head of the robot. AESUB green spray is pigment-free and gentle on people and the environment. “Many conventional sprays contain pigments such as the harmful titanium dioxide. It was important for us to develop a matting spray that facilitates scan progress and does not damage the object or pose a threat to the user,” explains Friedrich Schlott, AESUB Managing Director. “We also know from our own experience how tedious and time-consuming it is to remove the matting layer after the work is done. Fortunately, with the evaporating spray, this is a thing of the past and the throughput in the measuring room can be increased immensely,” continues Schlott.

When developing the different spray variants, AESUB’s team of experts kept an eye on the various requirements in measurement laboratories. While AESUB green is designed for use with spray robots and spray guns, the other sprays are offered in cans and are particularly suitable for smaller objects.

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