Contactless testing of packaging / Pierre Pfeffer in KUNSTSTOFFE INTERNATIONAL, Vol. 112, N° 2 (2021)  

[article]  inKUNSTSTOFFE INTERNATIONAL > Vol. 112, N° 2 (2021) . - p. 46-49 Titre : Contactless testing of packaging : Comparison of terahertz- and microwave-testing Type de document : texte imprimé Auteurs : Pierre Pfeffer, Auteur ; Thomas Hochrein, Auteur ; Giovanni Schober, Auteur Année de publication : 2021 Article en page(s) : p. 46-49 Langues : Anglais (eng) Catégories : Emballages en matières plastiques Mesures dimensionnelles sans contact Micro-ondes Térahertz Index. décimale : 668.4 Plastiques, vinyles Résumé : Terahertz and microwave methods offer a wide range of applications for testing of plastic packaging. Already established wall thickness measurements and defect detection are now joined by a wealth of other possible applications that promise process reliability and cost efficiency. Both systems show different strengths and are suitable for different applications. Note de contenu : - Differences between THé and MW - Saving costs and resources by inline testing - THz-systems advantageous with foams - Reliable recognition of defects in packaging - Moisture and filler content : further applications for the testin methods - Fig. 1 : The frequency range of terahertz and microwave technology lies between that of radio wave-based systems and that of infrared and UV light-based systems - Fig. 2 : Principle of thickness measurement: interfaces of different density lead to reflection of terahertz and microwaves. By measuring the temporal behavior and knowing the material-specific propagation speed, the distance traveled and thus the thickness can be inferred - Fig. 3 : Relationship between the refractive index, which can be determined in real time and inline, and the bulk density for various expanded polymers : since the frequency bandwidth is wider for THz systems than for MW systems, the former are more suitable for testing foams - Fig. 4 : THz and MW measurement techniques can be used to determine the moisture content of polymers. MW systems are particularly suitable for this purpose - Fig. 5 : Measuring the frequency-dependent absorbance allows conclusions to be drawn about particle sizes. A wide frequency bandwidth is an important criterion for this purpose - Fig. 6 : THz and MW methods can also be used for the identification of materials En ligne : https://drive.google.com/file/d/1Ps2ZPuXjEl3L6ADmWJx5uHS2fjowfmIZ/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35499 [article]

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Transparency in compounding / Pierre Pfeffer in KUNSTSTOFFE INTERNATIONAL, Vol. 111, N° 4 (2021)  

[article]  inKUNSTSTOFFE INTERNATIONAL > Vol. 111, N° 4 (2021) . - p. 10-13 Titre : Transparency in compounding : Inline testing methods for monitoring processes Type de document : texte imprimé Auteurs : Pierre Pfeffer, Auteur ; Norbert Halmen, Auteur ; Thomas Hochrein, Auteur ; Giovanni Schober, Auteur Année de publication : 2021 Article en page(s) : p. 10-13 Langues : Anglais (eng) Catégories : Analyse spectrale Assurance qualité Contrôle non destructif Matières plastiques Mesures optiques Micro-ondes Procédés de fabrication Térahertz Ultrasons Index. décimale : 668.4 Plastiques, vinyles Résumé : The quality of final products can be increased by using measurement technology for monitoring production processes. Interest in it is increasing especially for compounding. There are various existing methods of non-destructive testing that can also be used inline in the manufacturing process. The different methods are suitable for different applications: an overview of the current capabilities and limitations of the various inline methods. Note de contenu : - Ultrasonics : Proven, but temperature-dependent technology - Optical spectroscopy : Regulating color directly in production - Microwave and terahertz : Temperature-independent and non-contacting - The appropriate method for the particular application - Fig. 1 : An overview of electromagnetic and mechanical waves arranged in the order of frequency and wave length : The red colored areas represent the NDT methods used in plastics processing - Fig. 2 : Dependence of measurable ultrasonic amplitude (extinction coefficients) of filler content and the accompanying median size of chalk particles in plastics compounds: By using such databank-integrated calibration curves, both of these quality relevant features can be quantified inline by ultrasound - Fig. 3 : Process chain exemplified by color measurement of dyed plastics products: Dyed compounds are manufactured from various raw materials and processed further, either continuously by extrusion, or discontinuously to injection molded products. All along the process chain there are various possibilities for monitoring color quality - Fig. 4 : Dependence of a characteristic value, the so-called refractive index determined via terahertz from the degree of melting in a compound or the melt temperature: The degree of melting can be recorded inline by consulting a databank specific to the material - Fig. 5 : The dependence of so-called intensity, a characteristic value recorded via terahertz from the stochastic appearance of foreign materials in a compound (left), as well as a microscopic image of a machine-related wear particle in the melt (right): A threshold value (red line, left) can be defined by taking a variety of processing states into consideration beyond which the measuring signal can be univocally consigned to a foreign particle En ligne : https://drive.google.com/file/d/14HvEX29bLDS3vrJDpT7bgV9MOWqmqJhZ/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35712 [article]

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