Pandora - Glass thickness and Concavity measurement

The Pandora¬†is an in-line inspection system capable of measuring the glass thickness and bottom concavity of vials. These dimensions are mentioned in ISO8366-1-2018(E) as ‘S2’ and ‘t’. Measurements are performed optically with no need for physical contact and thus preventing any possible damage. The inspection system consists of an optical probe, horizontal sliding unit and a chromatic confocal sensor.¬†

The optical probe and the horizontal slide are mounted to the back of an indexed transport line as can be seen in the image to right. The sensor measures the distance to the first reflective surface (outer wall of the vial) and the second reflective surface (inner wall of the vial). Together with abbe-number (approximate measure of the materials dispersion) and the refractive index of the glass the thickness can be calculated. This measurement is a point measurement only. To be able to measure the concavity the sensor is moved across the surface of the vial and during the movement multiple point measurements are performed to create a profile. The image below shows the results of a typical measurement performed with the Pandora.

The further measurements that can be performed are:

  • Concavity measurement; this determines the depth of the bottom (base depth) at the center of the vial.
  • Maximum bottom thickness
  • Minimum bottom thickness
  • Average bottom thickness
  • Bottom thickness variation; this measurement determines the difference between the maximum and the minimum thickness


The inspection system can measure vials of 16 to 30 mm in diameter at a speed of 100 vials per minute. The inspection system is operated through Vimec standard V-Center software and can be mounted on new and existing lines.

Interested to find out how the Pandora can help you improve your inspection capability? Get in touch via the contact form or call us at +31 (0)40 255 06 07

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