Non-Contact Quality Control Measurement of Automobiles
In automotive production, accuracy is critical - no gap can be too wide and no offset too large. As a result, measuring instruments are required that deliver unambiguous results and leave no traces on the body paint after testing. Clearances and offsets on bodies are a key quality criterion for every production process in the automotive industry. Absolute - 100% - accuracy is therefore a must. Conventional scanning measuring methods have weaknesses: Classic measuring errors occur, for example when measuring with sliding calipers, due to skewed readings, undefined measuring force or inclined positioning. These operator errors lead to imprecise and unusable results. There is also a risk that the sensitive vehicle paint will be damaged by a mechanical measurement.
Simple and Straight Forward
To prevent errors and paint damage, the German high tech company Nextsense has developed the Calipri, an opto-electronic single-handed meter that detects different profile shapes fully with no contact, thanks in part to a board-level camera from IDS Imaging Development Systems, Inc. The measured profiles are used to calculate relevant features, such as clearances and offsets, preventing measuring errors caused by the user. Objective and reproducible at any time, the measured results are completely independent of operator influences. Plus, the non-contact measurement prevents damage to the instrument caused by lubricants, as well as to the surface being measured. Simple and straightforward, the Calipri measurement process takes approximately five seconds. To perform the measurement, the user holds the Calipri in his hand 10 cm above the measuring object, moving it around the object to capture the contours from several angles. A sensor connected to a tablet and the IDS camera scan the profile of the measuring object from different sides. Tilting is automatically detected, and the measured result is corrected accordingly. If the sensor is too far away from the object, an acoustic signal sounds. The Calipri evaluates the measured data itself and discards any unsuitable data.
Visualize and Analyze
USB 2.0 uEye cameras from IDS incorporated into the Calipri ensure 100% accurate measurements. The cameras meet the high standards set by the Nextsense engineers: compact dimensions, variable object installation, and power supply via USB 2.0. Inside the camera is a Wide-VGA-CMOS sensor produced by Aptina and a global shutter that delivers completely distortion-free images. Other criteria when selecting the camera included the high sensitivity of the sensor and the high frame rate. The user can easily switch to different IDS camera models or interfaces without any additional programming; in other words, the engineers have provided plenty of scope for future developments. To evaluate the measured data, Nextsense uses proprietary image processing algorithms. The measured values are supplied in XML or CSV format for processing on the tablet PC. The Nextsense Calipri Explorer software also enables measurements to be visualized and analyzed. Possible applications of Calipri single-handed meters are not limited to automotive technology. Different versions open up applications in rail vehicles, measurement of elastic profiles, weld seams, cracks, and bending contours.
