Germany-based Seidenader Maschinenbau and ilis offer new method to measure stress in glass pharmaceutical containers during manufacturing; real-time measurement detects cracks during pre-stage production, reduces fractures
MARKT SCHWABEN, Germany
May 25, 2012
– The companies Seidenader Maschinenbau GmbH and ilis gmbh present a new development for the reproducible measurement of stress in glass containers in-line in the manufacturing process.
Detection of cracks and leaks in pharmaceutical containers to ensure the integrity and sterility of the contents is one of the top issues which Seidenader have met by provision of various inspection methods. However, of course, only defects which already exist at the time of the inspection can be detected by such methods. Seidenader Maschinenbau GmbH in cooperation with ilis gmbh now present a method by which specific pre-stages of crack formation may be identified.
Mechanical stress can reduce the fracture strength and processability of glass containers. Even small residual stress can increase the likelihood of breakage or cracking significantly.
In a relaxed state, glasses are optically isotropic, i.e. the refractive index is equal in all spatial dimensions. The propagation speed of light depends, among other things on the density of matter. Mechanical stress causes deformations in the material structure, i.e. different particle densities in the various spatial dimensions. This ultimately results in different speeds of light in the medium - the refractive index is dependent on the direction, the medium is birefringent. This birefringence can be analyzed with a polarimeter, which determines the angle of rotation of the polarization direction of linearly polarized light as it passes through a sample.
So far, correct measurements of the rotation angles with manual polarimeters were time-consuming and experienced laboratory personnel was required. Improvements could be achieved with the development of automated imaging polarimeters, which allow for inspection of not just one point, but of the whole object, and also exclude operator-induced measurement errors by automation.
Despite short measuring times of a few seconds, previously available systems are not able to inspect pharmaceutical products at clock rates of 600/min. Only now with the consistent further development of the automated imaging polarimeter is it now possible to measure and evaluate mechanical stress in glass containers in real time.
With the integration of such a system into a fully automatic inspection machine, objective and reproducible measurements at production speeds of up to 600 products/min. can be recorded so that production induced stress is detected early. Containers with residual stress can be automatically removed from the production and discharged into the defect channel. Therefore formation of stress-related cracks in the mechanical stress in glass is recorded and evaluated inline.
Since 1895, Seidenader has been committed to manufacturing high-quality equipment for the pharmaceutical industry. For more than 20 years, we have also been developing in-house the intelligent vision systems for our automatic inspection machines. Expertise on material handling and inspection of a vast variety of pharmaceutical containers filled with liquid and dry sterile products, combined with the experience and feedback of our customers has helped us to create a full line automatic inspection machines: from handy table top units for laboratory applications to high-performance inspection machines for large production environment. Exterior washing machines as well as inspection and sorting machines for tablets and capsules complete the Seidenader product range. Seidenader meets the increasing requirements of the pharmaceutical industry by developing complementary inspection technologies, automation solutions for the control of complex packaging lines as well as comprehensive track and trace solutions. The head office of Seidenader Maschinenbau GmbH is located in Markt Schwaben near Munich. Since January 2011 Seidenader is part of the Körber Medipak Group.
About Körber Medipak
As a worldwide leading provider for pharma packaging systems and technology Körber Medipak is a high performing and reliable partner for the international pharmaceutical industry.
The group provides specialized machines, packaging material and customized services from one source. Thus Körber Medipak covers all areas of the packaging process for liquid and solid pharmaceutical products. The broad portfolio ranges from contract manufacturing, specialized packaging development, construction of customized packaging and inspection machines up to track and trace solutions, and patient-ready medication systems. The Körber Medipak group consolidates the know-how of Rondo AG, Dividella AG, MediSeal GmbH, Seidenader Maschinenbau GmbH, Weimer Pharma GmbH and AvidiaMed GmbH. With worldwide 924 employees Körber Medipak achieved sales volume of 146 mio. € in the year 2010.
The ilis gmbh is based in Erlangen and develops, manufactures and markets software solutions, instrumentation, and automatic test equipment for quality assurance in the glass and optics industries. With the measuring and test equipment of the StrainMatic and StrainScope series, the company focuses its development on imaging polarimeter systems for automatic and objective measurement of stress birefringence in glass and plastic.