GlasStress Ltd.

21, Akadeemia Tee, 12618 Tallinn
Telephone +372 655 5531
Fax +372 655 5532


Hall map

glasstec 2016 hall map (Hall 14): stand A07

Fairground map

glasstec 2016 fairground map: Hall 14

Our range of products

Product categories

  • 05  Measurement, testing, control technology and software
  • 05.01  Measurement and control technology, sensoring
  • 05.01.01  Measurement and control
  •  Measurement and control of glass tension

Our products

Product category: Measurement and control of glass tension

Scattered Light Polariscope SCALP-04

Scattered light polariscope SCALP-04 is meant for through-the-thickness stress measurement in architectural glass panels and automotive glazing. The polariscope is computer controlled. Handling of the polariscope is extremely simple: just place the the device on the glass panel to be measured and press slightly the button on the left side of the device. After ten seconds the stress profile through the panel thickness is shown on the screen of the laptop. Some additional measurements are needed for stress measurement near the edges and holes.

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Product category: Measurement and control of glass tension

Automatic transmission polariscope AP-07

Polariscope AP-07 is a computer controlled device designed for automatic stress measurement in solid and hollow axisymmetric glass products (drinking glasses, bottles, neck tubes of CRT bulbs, lamps, optical fibre preforms, etc.). It permits also edge stress measurement in glass plates and automotive glazing, thickness stress measurement in strips cut out from glass plates, and measurement of stress at edge corners. Photoelastic measurements are completely automatic and take from 2 to 10 seconds. After that stress distiribution in any section of the test object can be displayed on the screen. Diameter of the field of view is 40 mm. The measurement area can be easily displaced using the coordinate device with digital readout. Modern integrated photoelasticity algorithms are used for stress calculation from the measurement data. The polariscope can be used for stress measurement near the production line. Its handling does not need any knowledge about photoelasticity or stress analysis. The polariscope is delivered together with a laptop computer and software to control the measurements. 

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About us

Company details


Glasstress Ltd. was formed on the basis of the Laboratory of Photoelasticity of the Institute of Cybernetics at Tallinn University of Technology. The personnel of GlasStress Ltd. has 40 years of experience in measuring stress in glass articles, especially in articles of complicated shape. For that we have developed modern measurement technology as well as automatic polariscopes which are easy to handle and can be used in the vicinity of the production line.


Traditional photoelasticity premits only qualitative estimation of stress in glass articles of complicated shape. Errors in peak stresses may be manyfold. Manufacturing of resistant glass articles demands accurate knowledge of the residual stresses in order to optimize the glass manufacturing technology.

For measuring stresses in axisymmetric glass articles a new method, based on integrated photoelasticity has been developed. The method permits the determination of the distribution of all the stress components in solid and hollow glassware. Regions with highest stress can be easily found. The method has been successfully used for measuring stresses in drinking glasses, bottles, neck tubes of the CRT glass bulbs, lamps, optical fibre preforms, etc., for many companies. New projects concern development of photoelastic tomography for stress measurement in glass articles of arbitrary shape and of a portable scattered light polariscope for thickness stress measurement in flat glass.

The Market

GlasStress instruments and measurement technology have entered numerous markets from containers and tableware to automotive and architectural glass. Initially, GlasStress supplied instruments for laboratory use. Developments now concentrate on higher volume lower cost stress analysis equipment that may also be implemented as quality control instruments at the production line.

GlasStress is now developing and providing real-time, on-line inspection equipment for the broader manufacturing sector. The AP-06C and now the SCALP-01 are playing important role in the quality control of glass and translucent products. GlasStress is working to improve its customers productivity and product quality.

Relationships have been established with major glass manufacturers to develop process control systems for the manufacture of containers, tableware, architectural glass and automotive glazing.

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Company data

Target groups
  • Manufacturing, Processing and Finishing
  • Architecture / Construction
  • Solar Glass/Technical Glass