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WERIT Kunststoffwerke W. Schneider GmbH & Co. KG 

https://www.werit.de

Armaturen

Drucklufttechnik

Betriebsausrüstung / Betriebsmittel

Mechanische Konstruktionselemente

Maschinenelemente

Behälter / Silos

Lagereinrichtungen

Elektronik

Elektronik-Fertigung

Fasern

Kunststoff-Halbzeuge

Halbzeuge und Zwischenprodukte

Gehäuse aus Kunststoff

Kühlkörper

Elektromechanik

HV-Anwendungen / Hybridisierung / Elektrifizierung

Elektromobilität

Mobilität

Halbleiterfertigung

Halbleiterlaser, Diodenlaser

Photonik

Heizung

Haustechnik

Klemmen

Kunststoffverarbeitung

Lohnfertigung

Dienstleistungen

Lichtwellenleiter (LWL)

Palettiersysteme

Anlagen / Systeme

Fertigungsautomation

Palettierung

Werkstückspanntechnik, spanend

Spanntechnik

Polyethylen

Thermoplaste

Kunststoff Werkstoffe

Schalter, Taster

Schrauben

Normteile

Simulation Verpackung

Simulation

Software

Teile nach Muster

Verbindungstechnik

Bioplastics are comparable to conventional materials, not only in terms of their mechanical properties. By adding simple mineral additives the fire protection of these materials is improved substantially. Different flame retardants were tested for a sandwich board from bio-based polyurethane with linen cover layers, and their performance has been proven. 

Fire-Protected Sandwich Panels Made from Natural Fiber-Reinforced Bio-Based Polyurethane 

Biokunststoffe

Additive

Polyurethan

Flachfolien- und Plattenextrusion

Platten

Good Fire Protection with Simple  Flame Retardants 

A thermoplastic composite sheet based on TPU film reinforced with continuous carbon fibers has been developed for lightweight load-bearing structures. The orientation of the fiber plies in the thermoplastic composite sheet can be varied from unidirectional to multiaxial, and adapted to the load case. Economical and robust components can be fabricated using a laminate structure consisting of two thin outer layers of TPU composite sheet and a core of continuous glass fiber-reinforced polyamide 6.  

Thermoplastic Polyurethane Composite Sheet with Continuous Carbon Fiber Reinforcement 

Verbundwerkstoffe / Werkstoffverbunde

Faserverarbeitung

Ready for Large-Scale Production  

The aim of this joint project is to develop a production cell in which a rear license plate light can be manufactured with hybrid processes without any additional steps such as bonding. Some of the necessary analyses and pre-testing of the material combinations resulting from the structure of the product – plastic housing and optics plus metal conductive tracks – are presented in this article.

Lighting  solutions on various products. 

16:9

Manufacture of a Rear License Plate Light in a Highly Integrated Production Cell

Spritzgießen

Kunststoffverarbeitung: Verfahren

LED / OLED-Systeme und Faseroptik

Lichttechnik

Polymethylmethacrylat

Hybrid-Spritzgießen (Metall / Kunststoff)

Polycarbonat

What Is the Most Suitable  Material Combination?

In order to protect their offspring from being eaten by predators near the ground, green lacewings deposit their eggs on the underside of leaves – on the ends of stable silk threads. These so-called egg stalks are only around 15 micrometers thick and can easily hold the weight of the eggs. In order to produce these impressive fibers, the green lacewing excretes a protein secretion onto the leaf. The egg is then laid in the droplet and perpendicularly pulled out from the leaf. The resulting silk thread then hardens in the air. 

High-Grade Rigid Fiber for Lightweight Plastics 

Medizintechnik

Technik Trend

kunststoffe-international.com

Biofibers Made from Green Lacewing Silk 

The e.GO Life is an affordable electric car for short-range transport. Starting as a development project at the RWTH Aachen University campus, the first cars of this type were delivered in the middle of this year. For this car, the engineers use plastic panels for the vehicle’s body. The large-sized body panels are thermoformed by the plastics-processing company Parat in close collaboration with the plastic sheet manufacturer Senoplast.

All 59 plastic body panels of the e.GO Life electric vehicle were thermoformed very cost-effectively from semi-finished plastic products i. e. coextruded plastic sheets

59 Lightweight Components for the Body of the New Electric City Vehicle e.GO Life

Werkzeuge für Leichtbauwerkstoffe

Präzisionswerkzeuge

Leichtbau

Extrusion

Automotive

Fahrzeugbau

Lightweight Construction

The global market for PMMA continues to benefit from an increasing demand, mainly from the construction and electronics industry as well as the automotive and transportation sector. However, continuing raw material bottlenecks have damped sales, which has also pushed up the price for PMMA.

Lower energy consumption, better plant growth: a company in the Netherlands builds functional greenhouses with the help of lens optics made of a Plexiglas PMMA molding compound

Growth through Diversity for Molding Compounds and Semifinished Products

Technische Kunststoffe

Polymethyl Methacrylate (PMMA)

Lupine Lighting Systems manufactures extremely bright mountain bike lights with lenses made of Plexiglas. The molding compounds from Röhm meet the most important standards for e-bike and bicycle lighting.

A masterpiece of precision: UPT Optik in Nuremberg produces the lenses for Lupine in an injection molding process using the brand PMMA from Röhm. The material is unsurpassed in its transparency and light guiding properties

Technische Optik

Ingenieurwissenschaften

Optik

Bright Lights with Precision Lenses Made from Plexiglas

Atomic force microscopy can be used to determine various properties of polymer surfaces. However, until now it was still necessary to change the hardware on the probe for different measurement methods.

With the Tosca series, all AFM measurements can be carried out with only one actuator body and thus without hardware exchange

Characterize Plastic Surfaces More Easily with Atomic Force Microscopy

Messtechnik

Prüfen von Kunststoffen

Kunststoff

Bauwesen

Baustoffe

Measurements without  Hardware Exchange

The transition to electric cars is transforming automotive design. And so polymers producer Röhm has developed special polymethyl methacrylate (PMMA) molding compounds with this in mind. These are sold under the company’s well-known Plexiglas brand. At Fakuma, the company will be demonstrating how they can be used to combine design requirements and functional properties.

Plexiglas Resist AG 100 is used, for example, in Volkswagen’s ID.3 electric vehicle

Messe Fakuma

Greater Design Freedom for Electric Cars

Röhm produces antimicrobial PMMA for transparent partitions.

Plexiglas XT Antimicrobial is an extruded sheet material with a special surface treatment on both sides. The coating contains a formulation that controls microbial growth

Disease Protection by PMMA

Zumtobel produces moisture-proof luminaires from Plexiglas molding compounds, the polymethyl methacrylate from Röhm.

The Amphibia PM moisture-proof luminaire from Zumtobel is made using the Plexiglas Resist zk5BR special molding compound.

Leuchten / Lichtmanagement

High Light Efficiency for a Luminaire

PMMA for lights, lighting solutions, automotive exteriors, and household appliances will take center-stage on Röhm’s booth at this year’s show.

Displays with a black panel effect for household appliances can be implemented in PMMA.

Messe K-Kunststoffmesse

More Design Freedom for Lights

The strong demand for PMMA is based on the continually expanding diversity of applications.

Design trend light: in the TIR lens LFO by Bartenbach and kdg Opticomp made of a Plexiglas PMMA of Röhm, the surface of the lenses is structured using free-form surface facets in such a way that the light appears homogeneous.

Trotz Rohstoffengpässen und Turbulenzen in wichtigen Branchen stehen die  Zeichen für PMMA auf Wachstum

Polymethyl Methacrylate (PMMA): Turbulence in Key Industries

Kennzahlen

Qualitätsmanagement

Despite Raw Material Shortages, the Signs for PMMA Point to Growth

Optically excited Lockin-Thermography is well suited for fast and robust detection of near-surface defects in isotropic and fiber-reinforced plastics. The resulting phase images are driven by the excitation frequency as a measurement parameter and can be analyzed in the one-dimensional case for depth-selective evaluation. For real test specimens, however, diffusive heat conduction processes overwhelm which makes accurate defect characterization from phase images much more difficult. Neural networks are used within this work to evaluate multiple phase values of different excitation frequencies with each other and thus implement for the first time a quantitative defect characterization in isotropic and fiber-reinforced plastics based on a LSTM-CNN hybrid model. It is shown that the already good prediction values of the neural network are again significantly improved by additional training data obtained from heat flow simulations.

Representation of the experimental setup: thermographic camera (bottom left), photodiode (top left), VCSEL array (right), CFRP test specimen (center).

Industrie 4.0 für die Qualitätssicherung

Industrie 4.0

Künstliche Intelligenz für die Qualitätssicherung

Andere Werkstoffe

Faserverbundwerkstoffe

Defect characterization in isotropic and fiber-reinforced plastics using active thermography and neural networks

Polymer Optical Fibers Increase the Reliability of MRI Images

Patient movements can severely affect the quality of MRI and CT images. A new approach detects the movements and subsequently incorporates them into the image evaluation by means of correction algorithms. This significantly improves the image quality. For the detection of the patient’s movements, the use of polymer optical fibers is suitable.

Light-guiding materials such as optical fibers fulfil important functions not only in data communication, but also in medical technology. Polymer optical fibers (POFs) made of special plastics have a number of advantages over optical fibers made of silicate glass, both in short-distance communication and in illumination and sensor technology. The first POFs were developed as early as 1967 by DuPont from polymethyl methacrylate (PMMA) [1]. More recently, a number of other polymers have been used in addition to PMMA for manufacturing. Of particular note are polycarbonate (PC) and thermoplastic polyurethane (TPU), but also various block copolymers such as the fluoroplastic Cytop from AGC Chemicals and the cyclo-olefin copolymer Zeonex from the American manufacturer Zeon [2].

Due to the lower elastic modulus compared to optical glass fibers, POFs are more flexible even with large fiber diameters and can therefore be easily integrated into textiles. In addition, they enable easier light coupling and better light capture. They are also cheaper, easier to handle and offer high electromagnetic immunity (EMI) [3]. Because of these advantages, POFs are predestined for short-range communication in motor and rail vehicles, electronic devices and building networking, among other applications. They are also suitable for measuring and monitoring a range of environmental parameters such as pressure, temperature, pH values, body movement, velocity, oxygen saturation and friction [4 – 9].

Melt Spinning Enables Adaptation of Different Fiber Properties

Besides production by hot drawing and extrusion, melt spinning (Fig. 1) is one of the most suitable processes for the production of POFs [10]. Melt-spun fibers with adjustable fiber attenuation and degree of hardness or flexibility can be produced from the aforementioned polymers. By adjusting the process parameters and the nozzle geometry, different fiber cross-sections (circular, square, trilobal, etc.) and different fiber diameters are possible.

In addition to the mentioned fields of application, POFs can also be used for medical applications such as health monitoring and motion analysis due to their pressure sensitivity. The Institut für Textiltechnik of RWTH Aachen University (ITA), Germany, and the Stimulate research campus led by Siemens are currently working on such an application in a joint project funded by the German Federal Ministry of Education and Research (BMBF). In the Stimulate project, the two development partners are investigating the possibility of body movement monitoring during medical imaging, such as magnetic resonance imaging (MRI) or computer tomography (CT), using melt-spun POFs. Patient movement during imaging results in significant artefacts and thus unusable scans. However, with precise knowledge of the body movements during the measurement, it is possible to implement appropriate countermeasures to restore the image quality. Thus, a repeat performance of the time-consuming and cost-intensive examination can be avoided.

Developments in the field of POF and advances in sensor technology have pushed the application boundaries for human motion analysis [9]. For example, POFs are currently being investigated for motion analysis in smart carpets and as strain gauges [15]. By combining a defined pressure sensitivity and targeted light coupling, they enable measurements of dynamic patient movements [9]. In addition, the electromagnetic interference immunity makes POFs ideal candidates for medical applications, especially in MRI, which are highly susceptible to such interference.

The development of POFs that have the necessary pressure sensitivity and the integration of the fibers with regard to the required light coupling is the focus of the Stimulate project. The technological principle is based on the so-called cross-coupling between two POFs. Within the framework of the project, a textile grid is being developed that provides the foundation for patient movement monitoring and image correction in MRI or CT scans.

The textile grid is made of two different POF systems. The first fiber system is connected to a light source and consists of flexible, soft POFs. They are not conventionally available on the market and are therefore produced by the researchers themselves as part of the project. The first fiber system is referred to as the driving fiber in the following. The second fiber system consists of a PMMA POF (hereafter referred to as sensing fiber), which has a low attenuation, is dimensionally stable and is connected to a photodiode. The main requirement for the POF is thus, in addition to light conduction, primarily the pressure force-induced cross-coupling of light between the driving fiber and the sensing fiber. The dependence of the optical properties on the compressive stress of the textile grid plays the decisive role in the underlying operating principle.

Several internal and external influencing factors (raw materials, processing conditions and fiber properties such as diameter, cross-section, crystallinity, etc.) must be taken into account in the development of the POF and the textile grid. For this purpose, ITA and the Hochschule für Telekommunikation Leipzig, University of Applied Sciences (HfTL) in Leipzig, Germany, have recently produced titanium dioxide (TiO2)-doped POFs with a trilobal cross-section by compounding and melt-spinning PMMA [13, 16]. Radiation patterns within the cross-section of the melt-spun fibers were also investigated using ray tracing simulation [17, 18].

What Is the Effect of Different Fiber Properties?

In some previous work on this project, the researchers developed a 2D pressure sensing device by cross-coupling between a driving fiber and a sensing fiber [17, 19, 20]. TPU and PMMA fibers were fabricated for the experiments. It was shown that the differences in the degrees of hardness between the two fiber systems are decisive parameters for increasing the contact area under pressure. Various influencing variables such as the fiber cross-section, the crossing angle and the influence of pressure on the sensitivity of the structure were also investigated [17–20]. The researchers found that smaller crossing angles result in higher cross-coupling efficiency, while the increase in pressure also increases the sensitivity. The prototype structure developed with these findings was subsequently presented as a sensitive 2D multitouch system [17].

Melt-spinning tests on eight types of transparent TPU from BASF, Covestro and Lubrizol enabled the production of monofilament driving fibers with different diameters from 0.2 to 1 mm (Fig. 2) for coupling with commercially available PMMA fibers with a diameter of 0.5 mm. Process parameters such as polymer throughput, drawing ratio and winding speed were varied in the process. A spinning system from Fourné Maschinenbau and spinnerets from Sossna with an L/D ratio of 4 and a capillary diameter of 1 to 2 mm were used to produce the driving fibers.

Appropriate Combination of Driving and Sensing Fibers

The attenuation measurements on a plastic sheet showed considerable differences between the raw materials (Fig. 3). Nevertheless, some of the driving fibers are suitable as counterparts for the PMMA sensing fiber in terms of attenuation coefficients and flexibility. The integration of selected fibers into a 3D-printed demonstrator (Fig. 4) at the Stimulate research campus by Otto-von-Guericke University in Magdeburg, Germany, showed that the pressure sensitivity of the driving fiber and the light coupling into the sensing fiber are crucial for the development goal.

A very important factor in the system is also the sensitivity when measuring the captured light intensity. Therefore, the driving fiber should have a high light emission, while the sensing fiber must capture as much of the emitted light as possible in order to guide it into a transparent and safe medium. This allows the photodiodes to detect and measure the light intensity. The necessary optomechanical connections are designed to have minimal light absorption and sufficiently high power. A suitable approach for pressure detection and image correction in MRI is shown in Figure 5.

The knowledge gained in the Stimulate project paves the way for using POFs in medical imaging. The development is based on the flexibility of transparent POFs and the pressure-induced light emission from a driving fiber into a sensing fiber through cross-coupling. By capturing the light signals with photodiodes, this leads to a visual image in a 3D-printed demonstrator. These pressure-induced measurements are the input data for image correction algorithms in medical imaging devices such as MRI or CT, as they reflect the patient’s body movement during imaging. In the future, this approach will be tested in application-oriented tests on medical imaging devices using a prototype of the developed textile grid.

[1] Derick B, Synder J. Luminous Textile Products. USA Patent No. 1967;3508589.

[2] Zubia J, Arrue J. Plastic optical fibers: An introduction to their technological processes and applications. Optical fiber technology. 2001;7(2):101–40.

[3] Bunge C-A, Beckers M, Gries T. Polymer Optical Fibres: Fibre Types, Materials, Fabrication, Characterisation and Applications: Woodhead Publishing; 2016.

[4] Guignier C, Camillieri B, Schmid M, Rossi RM, Bueno M-A. E-knitted textile with polymer optical fibers for friction and pressure monitoring in socks. Sensors. 2019;19(13):3011.

[5] Janting J, Pedersen JK, Woyessa G, Nielsen K, Bang O. Small and robust all-polymer fiber Bragg grating based pH sensor. Journal of Lightwave Technology. 2019;37(18):4480–6.

[6] Cheng X, Bonefacino J, Guan B, Tam H. All-polymer fiber-optic pH sensor. Optics express. 2018;26(11):14610–6.

[7] Quandt BM, Boesel LF, Rossi RM. Polymer optical fibres in healthcare: Solutions, applications and implications. A perspective. Polymer International. 2018;67(9):1150–4.

[8] Kam W, O‘Sullivan K, O‘Keeffe M, O‘Keeffe S, Mohammed WS, Lewis E. Low cost portable 3-D printed optical fiber sensor for real-time monitoring of lower back bending. Sensors and Actuators A: Physical. 2017;265:193–201.

[9] Leal-Junior AG, Diaz CA, Avellar LM, Pontes MJ, Marques C, Frizera A. Polymer optical fiber sensors in healthcare applications: A comprehensive review. Sensors. 2019;19(14):3156.

[10] Beckers M, Schlüter T, Vad T, Gries T, Bunge CA. An overview on fabrication methods for polymer optical fibers. Polymer International. 2015;64(1):25–36.

[11] Leal-Junior AG, Frizera A, Marques C, Sanchez MR, Botelho TR, Segatto MV, et al. Polymer optical fiber strain gauge for human-robot interaction forces assessment on an active knee orthosis. Optical Fiber Technology. 2018;41:205–11.

[12] Bunge C-A, Mohr B, Vad T, Beckers M, Gries T, editors. Non-circular side-emitting fibers for directed lighting. Micro-Structured and Specialty Optical Fibres V; 2018: International Society for Optics and Photonics.

[13] Bunge CA, Mohr B, Vad T, Beckers M, Gries T. Fabrication and analysis of side‐-emitting poly (methyl methacrylate) fibres with non‐-circular cross‐-sections. Polymer International. 2018;67(9):1170–8.

[14] Bunge C-A, Kallweit JP, Al Houri M, Mohr B, Bērziòš A, Grauberger C, et al. Textile Multitouch Force-Sensor Array Based on Circular and Non-Circular Polymer Optical Fibers. IEEE Sensors Journal. 2020;20(14):7548–55.

[15] Kallweit J, Bunge C-A, Al-Houri M, Mohr B, Bērziņš A, Grauberger C, et al., editors. Textile Touch-Sensor Array based on Circular and Non-Circular Polymer Optical Fibers. 2019 IEEE International Conference on Flexible and Printable Sensors and Systems (FLEPS); 2019: IEEE.

[16] Bunge C-A, Kallweit J, Colakoglu L, Gries T, editors. Fiber Cross-Coupling Mechanisms in Optical Pressure Sensor Arrays. 2020 IEEE Sensors; 2020: IEEE.

[17] Bunge C-A, Kallweit J, Colakoglu L, Gries T. Analysis of Fibre Cross-Coupling Mechanisms in Fibre-Optical Force Sensors. Sensors. 2021;21(7):2402.

RWTH-Aachen Inst. f. Textiltechnik (ITA) 

https://www.ita.rwth-aachen.de

Ausgabenartikel

Fig. 2. Light microscope images of the cross-section of melt-spun POFs made of TPU: the melt-spun POFs made of Elastollan 1180 from BASF (left) have a density of 1.08 g/cm3 and were produced at a polymer throughput of 5.6 g/min using a spinneret with a capillary diameter of 1.5 mm, a draw ratio of 1 and a winding speed of 23 m/min. The melt-spun POFs of Covestro’s Desmopan 9385 has a density of 1.18 g/cm3 and was produced at a polymer throughput of 4.8 g/min using a spinneret with a capillary diameter of 1 mm, at a draw ratio of 2 and a take-up speed of 23 m/min.

Fig. 3. The attenuation measurement reveals large differences in the materials. Materials 1160 (BASF) and 3360 (Covestro) are selected for their lower attenuation and smaller deviations.

Fig. 4. Schematic view of the 3D-printed demonstrator: important for a correct measurement result are the pressure sensitivity of the driving fiber and the light coupling into the sensing fiber as well as the sensitivity when measuring the captured light intensity.

Fig. 5. Final approach of the project for image correction: via the POF pressure measurement mat integrated into the MRI, the patient’s movements can be precisely recorded.

Fig. 1. POFs with different fiber diameters and cross-sections can be produced using the melt spinning process.

KUint3-22_ITA_Pursche - Hauptartikel

Dr.-Ing. Mohammadreza Naeimirad has been working since 2017 as an Assistant Professor at Razi University, before joining ITA as a research fellow at RWTH-Aachen University, Germany, <a href="mailto:m.naeimirad@razi.ac.ir">m.naeimirad@razi.ac.ir</a>

Mark Pätzel, M. Sc., has been working as a research assistant at the ITA since 2020 on the production and processing of polymer optical fibers (POFs) after completing his mechanical engineering degree at RWTH-Aachen University; <a href="mailto:mark.paetzel@ita.rwth-aachen.de">mark.paetzel@ita.rwth-aachen.de</a>

Alexander Warsch is a M. Sc. student at OVGU Magdeburg, Germany.

Dr.-Ing. Franz Pursche has been working since 2020 as the group leader of Monofilament Technology group after receiving his Ph. D. from RWTH-Aachen University; <a href="mailto:franz.pursche@ita.rwth-aachen.de">franz.pursche@ita.rwth-aachen.de</a>

Jan Kallweit, M. Sc., has been working as a research assistant at the ITA since 2018 on POFs after completing his mechanical engineering degree at RWTH-Aachen University; <a href="mailto:jan.kallweit@ita.rwth-aachen.de">jan.kallweit@ita.rwth-aachen.de</a>

Robert Kowal, M. Sc., has been working as a research assistant at OVGU Magdeburg since 2020 on hardware development for interventional magnetic resonance imaging after completing his medical engineering degree at OVGU Magdeburg.

Dr.-Ing. Enrico Pannicke has been working since 2018 as a group leader at OVGU.

Prof. Thomas Gries has been working since 2000 as the director of ITA at RWTH-Aachen University.

The work of this paper is partly funded by the Federal Ministry of Education and Research within the Research Campus Stimulate under the number 13GW0473A and 13GW0473E. The authors gratefully acknowledge the support.