The glass changes it's shapes by heated and molded duringmanufacturing
process. Regardless of how excellent shape and color is, the distortions
can occur within the glass invisibly if proper annealing* is not carried
out.
**annealing: the process of heating up to an appropriate temperature, then
holding at that temperature then followed by slowly cooling. By this process,
it removes residual stresses, reducing hardness, improving machinability,
enhancing cold working, and adjusting crystal structure, etc
Products with distortions are fragile and can easily break with even a
slight impact. In extreme cases, the unevenness can naturally cause curvature
or cracks. Distortion tester can easily identify these imperfections in
inadequately annealed products. Another distinctive feature of this product
is the ability to observe the striae caused by refractive index imbalances.
The rotating frame has markings distributed from 0° to 100°. With 0°representing
the normal state and the most intense colors of distortion appearing at
the 90°position.
For the inspection, the acceptable quality limit is set by the number appears
on the rotating frame. Based on that, it can be judged that the annealing
is insufficient if the color of distortion can be observed at a lower value
on the scale than where the acceptable quality limit begins to show color.
(If the annealing process is sufficient, distortions will not be visible.
If the annealing is insufficient, the more intense the colors will appear.
Additionally, the appearance of distortions can vary slightly depending
on the sample.) |
