Agfa-Gevaert HealthCare GmbH, a leading manufacturer of IT and imaging systems for health facilities has been relying on measuring technology from Carl Zeiss since 2009 when they acquired the ACCURA measuring machine.
According to Maximilian Fischer, Sheet Metal Production Manager at Agfa-Gevaert HealthCare, it takes them a mere three minutes now instead of 45 minutes for the measuring cycle of a single optical disk. The company was earlier using an optical single-point stylus for quality inspection that not only took a long time for measurement but also caused the test piece to vibrate during the process.
Agfa-Gevaert HealthCare GmbH specialises in digital radiography and the optical disks are used by radiologists to capture X-rays. The company’s product line also includes the cassettes on which they are stored in addition to digitizers and printers. Agfa produces over 30,000 disks each year.
The disks, manufactured in Schrobenhausen comprise of an aluminium alloy featuring a phosphor or acicular crystal coating. Before this coating is applied, Agfa must ensure that the disk is absolutely flat so that the images retain their details. Blurry images would make a diagnosis more difficult or impossible.
The disks must be flat to also ensure they can be properly read and then deleted for further use in the digitizer. An exact measurement gives Agfa a distinct advantage in the market.
However, the material warps throughout the manufacturing process, requiring the curvature, which is usually invisible to the naked eye to be completely eliminated using several defined process steps.
Agfa installed the ACCURA bridge-type measuring machine with the optical LineScan laser line scanner from Carl Zeiss Industrial Metrology in the fall of 2009. For a measurement, the disk is suspended from three points at an angle of 10 degrees. Agfa inspects the aluminium disk exactly in the position in which it must later achieve maximum flatness: when reading the image data in the digitizer.
An optical measurement is the only option for measurement as a contact probe would move and warp the disk.
During the measuring process, which is synchronised to the process requirements at Agfa, the LineScan sensor scans the disk in 16 paths and generates 1,470 precisely defined image points on the disk. CALYPSO software displays them at 100x magnification to make the curvature visible to the naked eye, enabling the user to see surface deviations in micrometres.
The coloured display also helps to quickly and reliably detect unevenness, based on which a suitable strategy is developed for the subsequent alignment process and the disk sent back for a measurement following alignment.
Key benefits of the LineScan sensor:
- High detail resolution of up to 250,000 measuring points per second
- Maximum frequency of 1,000 Hertz
- Virtually captures objects in full within seconds, saving time
- Automatically and reproducibly measures workpieces without requiring employees to configure the system
- Provides non-contact information about the test object down to the micrometre regardless of surface colour, gloss or extraneous light
- Prevents contamination and damage to flexible workpieces sensitive to contamination during quality inspection
Markus Rupp, application expert for laser sensors at Dr. Wolf & Beck GmbH, a Carl Zeiss subsidiary specialising in noncontact, optoelectronic distance sensors says that the requirements on quality are tremendous in the medical systems industry in addition to the increasing cost and time pressures. Many manufacturers are aware that they can save considerable time and increase the quality with the right measuring machines.
With LineScan, Agfa has been able to reduce the time needed for a measurement by more than 90%, taking about three minutes for each disk. In addition to quality improvement with LineScan, Agfa benefits from a considerably more reliable, easy-to-use measuring system.