Tension Scanner (TRL 6)
for detecting and evaluating tension in transparent articles
With this scanner, stresses and defects in transparent articles can be visualized and measured extremely precisely. In contrast to cameras, the scanners have a much higher depth of focus and are at the same time extremely robust against the refractive power of the objects. With uniaxial arrangements, for example, 70-90% of the volume of pipes > 100 mm in diameter could be checked for stresses and defects at the same time. A full inspection is possible with a 2-axis scanner. For pipes with a known wall thickness (e.g. by measured by our I-Mike systems), which were guided vertically through the measuring field in production, stresses in the material could be measured so precisely that the pull-off forces in production could be determined - an essential step for direct control of the most important variable in glass tube production. The scanner must be attached to the hot end of the process.
In addition to checking for defects, a measurement, test or control of the stresses in the material can be carried out.
Control of stresses in glasses
If, in addition to checking for defects, a measurement, test or control of the tension in the material is to be carried out.
Controlling the annealing of transparent articles
With the scanner, the achievement of a maximum target tension pattern can be detected and achieved directly.
Glass production
The optical measurement of the pull-off force allows direct force control.
Specifications
- Transparent (transmission > 10%) clear or colored articles
- Diameter < 150mm
Imaging telecentric retroreflex laser scanners with polarization option
The scanners provide images at their image interface (just like line scan cameras) from which the following variables can be determined:
- Defect sizes
- Tension pattern
- Birefringence (when the optical path length through the material is known)
- Pull-off force (if the path length through the material and the stress-optical coefficient of the material are known)
- Depending on scanner type and material
- For glass tubes a resolution of phase differences of 0.1 nm has been achieved
160(W) x 100mm(D)
3R
- Combined transmitter / receiver unit (emits the laser beam)
- Retroreflector (behind the test object)
- 24V supply unit (power pack or supply unit with integrated PC)
- Robust against object displacement
- Minimum effort for adjustment
- Image interface (GiG-E or CameraLink)
- RS-232 interface for parameter setting
OPOS Scanner Player (OSP) for acquiring images and configuring the scanners. A complete evaluation software (Purity) with production line interface is available from our partner Fraunhofer IOSB.
Application examples
The figures below show the characteristics of the measurement of the pull-off force, which was recorded with the Purity software from Fraunhofer IOSB on a glass tube with a diameter of 30 mm and a wall thickness of 3 mm in the sketched test setup. A standard deviation of the pull-off force of <0.5 N was achieved
In the images, interference effects such as stress patterns or stress waves in the material, for example when pipes are cut, can be directly observed (see image below left). A minimization and thus optimization of the production process can be directly observed. At the same time, defects in the material can be displayed directly and recognized automatically (see figure on the right).
Send us your samples for a first free test or let us convince you with a device demonstration in your house!
We would be adapt to adapt our sensors to your application or develop new functions for you.
Patents
- M. Hartrumpf, "Laserscanner-Meßsystem"; DE19806288A1
- M. Hartrumpf, "LASER SCANNER MEASUREMENT SYSTEM"; EP1056987A1
- M. Hartrumpf, "Laser Scanner Measurement System"; US6858836B1
- M. Hartrumpf, "Vorrichtung und Verfahren zur optischen Charakterisierung von Materialien": EP11760701.0
- M. Hartrumpf, "Apparatus and method for optically characterizing materials": US9222879B2