Award for Technical Author on Additive Manufacturing

On October 16, 2019, on the first evening of the K fair in Düsseldorf, Germany, Carl Hanser Verlag awarded the Dr. Richard Escales prize for the eighth time in memory of the founder of the journal Kunststoffe.  Prof. Dr.-Ing. Andreas Gebhardt achieved the award for “outstanding achievements in the advancement of technical knowledge”, as the citation on the certificate states.

On October 16, 2019, on the first evening of the K fair in Düsseldorf, Germany, Carl Hanser Verlag awarded the Dr. Richard Escales prize for the eighth time in memory of the founder of the journal Kunststoffe. Prof. Dr.-Ing. Andreas Gebhardt achieved the award for “outstanding achievements in the advancement of technical knowledge”, as the citation on the certificate states.

It is important for me to systematize things,” commented Prof. Andreas Gebhardt (Fig. 1) on his prolific publishing activity in the field of additive manufacturing right from the early days of this technology. The first edition of his ground-breaking work “Additive manufacturing” appeared in 1995 in German, while his most recent German book “Produktgestaltung für die Additive Fertigung” (Product design for additive manufacturing) (co-authored by Julia Kessler and Alexander Schwarz) was finished just in time for K. In between there have been numerous books and journal publications in German and English.

Gebhardt studied mechanical engineering at RWTH Aachen University. As Director of the Laser Bearbeitungs- und Beratungszentrum NRW GmbH, Aachen, Germany, in the early 1990s, he came into contact with rapid prototyping, which initially was an important driver for the use of the additive manufacturing machines developed only a few years previously.

In 2000, he was appointed Professor of Advanced Fabrication Technology and Rapid Prototyping at the FH Aachen University of Applied Sciences, to which institution he has remained faithful as an emeritus lecturer since his retirement in August 2019. In addition, he is active as the Director of the Centrum für Prototypenbau GmbH, Erkelenz, Germany, and the IWF Institut für werkzeuglose Fertigung GmbH, Aachen.

Previous prizewinners, most of whom have been prominent authors of numerous technical articles and books, were presented with a certificate and a stylish fountain pen engraved with their name. But what could be better as a symbol of achievements in our industry than a trophy made of plastic? Together with its partner, the Association of German Tool and Moldmakers (VDWF), Carl Hanser Verlag took this idea to the ultimate. The 15 cm-high award is not only made of plastic but is a miniaturized replica of a mosaic that an Italian artist, “Lady Be”, was commissioned to produce in 2019 – made of plastic pieces.

As the model for this artwork, she used a drawing by the mainly USA-based artist, Marie Stoppe, who did a portrait of Dr. Richard Escales during his lifetime, probably around 1911, when the journal Kunststoffe appeared for the first time.

The artwork that “Lady Be” created from the original drawing in her own style using small plastic pieces and toy figures is brightly colored with an extremely fissured surface (Fig. 2). So it quickly became clear that, with a required production quantity of only 1, additive manufacturing was the process of choice here, although realization of the project would present a challenge. Soundings in the industry elicited a negative response: “It won’t work”, was the comment often heard – it was thought that, in practice, it would not be possible to scan the mosaic without losing geometrical and color data and even if it were possible, it would not be easy to reproduce the variety of colors.

Finally, Antonius Köster dared to capture the data of the original. But as our visit to Meschede, Germany, with the original mosaic in our hand luggage showed, there were initially “holes” in the data set, despite the virtuosic use of a scanner (type: Space Spider, manufacturer: Artec, Luxembourg, Fig. 3, left). The painted surface reflected too brightly in many places. The answer was a matting spray that suppressed the reflections for several minutes before the thin spray layer evaporated without leaving a residue. However, because the scanner cannot “see round corners”, “holes” in the data for 3D printing still had to be closed – a task that, given the complexity of the mosaic, the Geomagic Freeform (manufacturer: 3D Systems, Moerfelden-Walldorf, Germany) completed superbly.

As far as printing technology was concerned, the choice fell on the J750 from Stratasys, which cures photopolymers with UV light. The full-color printer can be loaded with up to six materials (including an auxiliary material). Just the five solid colors black, white, cyan, yellow, and magenta give a color portfolio of over 500,000 color variations, which are Pantone-validated.

Consultation at the 3D Printing Fair  in Erfurt

So much for the theory. Whether this would all actually work naturally had to be discussed with the printer manufacturer. For this purpose, Rapid.Tech (the trade and consumer fair for 3D printing technology) in Erfurt, Germany, offered a convenient meeting place (Fig. 3, center). As it turned out, Stratasys Manager Michael Eichmann was enthusiastic about the idea. Not long after, the first prototype prints were produced – in the original size (Fig. 3, right), thanks to the build volume of 500 × 400 × 250 mm, and in lively colors that came extremely close to those of the original.

However, since the award would have to fit in a display case or on a desk or shelf, it had to be just half the size of the original and also be provided with a plinth. Appropriately at a 3D printing event once again, the Köster/Eichmann duo discussed the new data set and so cleared the way for the final print, in which the miniaturized portrait of Dr. Richard Escales and his plinth were created.

The plinth contains information that makes the piece unique, even if, at the next award ceremony in three years’ time, the artwork is reproduced in the same way. On the back of the plinth are details of the companies Antonius Köster and Stratasys, whom we would like to thank here for their support in realizing this project. On the front are the year and name of the recipient of the award. Here the J750 shows that – thanks to the sixth jet – transparent material can also be processed. Consequently, the white text appears to float in the transparent areas.

From Candidate Selection to the Award Ceremony

In a departure from the previous internal selection process for the award, this year there was a call for candidates, which was announced in spring 2019. The call elicited many nominations for potential prizewinners, from whom the editors of Kunststoffe picked the winner of the award in June. The identity of the industry personality concerned was kept secret until the award ceremony took place. The presentation ceremony for this year’s Dr. Richard Escales prize was again jointly organized by Carl Hanser Verlag and the Association of German Tool and Moldmakers (VDWF). Hanser Publishing Director Andreas Klein and VDWF President Prof. Thomas Seul were pleased to welcome over 100 guests from the plastics industry to the award ceremony.

Fig. 3. From artwork to replica: the data were read with a hand scanner in about an hour (left); Antonius Köster discusses the result at a 3D fair (center); Stratasys Manager, Michael Eichmann, with a print in virtually the original size (right), which at first glance cannot be distinguished from  the original

Fig. 2. The original mosaic of Dr. Richard Escales, founder of the journal Kunststoffe, based on a black and white drawing and created in 2019 from plastic pieces and toy figures by the Italian artist Lady Be

MuM-Escales - Hauptartikel

Verfahren für die additive Fertigung

Messe K-Kunststoffmesse

kunststoffe-international.com

Bildverarbeitungs-Software

Fertigungsautomation

Bildverarbeitung

Klotz, Karlhorst, Dr.

Anlagen Additive Fertigung / 3D-Druck, Kunststoff

Anlagen für die Additive Fertigung

Additive Fertigung

Additive Manufacturing of Plastic Components in a High-Speed Process Using Standard Pellet Stock

3D printing is a fast-growing market, opening up completely new product and manufacturing options for customers and industry. The newly developed SEAM process significantly extends the options for the efficient manufacture of printed components. An impression of this is conveyed by the example of a fiber-reinforced clamping fixture.

The SEAM process (screw extrusion additive manufacturing) takes a new approach to high-speed additive manufacturing of plastic components. With printing speeds of up to 1 m/s, it was developed by the Fraunhofer Institute for Machine Tools and Forming Technology (IWU) in cooperation with Metrom GmbH. The 3D printer is based on a combination of an extrusion-based plasticating unit that processes plastic pellets (including fiber-reinforced material), and parallel kinematics for rapid highly dynamic movements with accelerations up to 10 m/s² and very high positioning accuracy.

Thanks to its mechanical design, it can cross the limits of existing processes and establishes a new generation of 3D printing processes, which is eight times faster than conventional 3D printing. The SEAM process is very material efficient, since it allows components to be manufactured without supporting structures. There are two versions:

<ul><li>The SEAM-Hex system has a table that moves in three different spatial directions and a fixed printing head (Fig. 1).</li><li>The PentaSEAM system is characterized by a movable printing head with fixed build platform or optionally a round table and a linear axis for enlarging the build chamber (Fig. 2).</li></ul>

The construction results in parallel kinematics, 6-axis in the first case and 5-axis in the second case.

In the SEAM process, output rates of up to 8 kg/h are generated, for example with a 1 mm nozzle. For comparison, a filament-processing FLM process requires about 20 h for 1 kg of printed component mass, corresponding to a mass output of only 0.1 to 0.2 kg/h. Since standard plastic pellets are processed instead of an expensive FLM filament, there is a huge material cost saving, e. g. a factor of 200, for PA6-CF compared to familiar FLM/FDM (fused layer and fused deposition modeling).

Different plastics, such as thermoplastic elastomers, polypropylene and, as here, a polyamide 6 with 40 % carbon fibers (PA6-CF) have already been tested. These are materials relevant for industry with high stiffness and strength, or high elasticity, which cannot be processed with conventional 3D printers.

Because of the short manufacturing times, a closed material loop and the possibility of being able to subsequently subtractively process the components in one clamping (additive-subtractive hybrid manufacturing), the component costs can be reduced to a fraction, in particular for small series and prototyping, while achieving the same surface quality as for the standard FLM process.

Conventional injection molded parts are usually designed as thin-walled structures according to the process and design. The SEAM process permits different wall thicknesses to be generated in one printed track, depending on the table speed and output rate of the extruder. Thus, for example with a 1 mm nozzle and PA6-CF as material, strand widths of between 1.2 and 3.1 mm can be obtained.

Compared to FDM/FLM, where, within narrow limits, the realizable strand width approximately corresponds to the nozzle diameter, the SEAM process is characterized by high variability. This also applies in an unfavorable parameter set – e. g. a low strand height or a high melt stream – has been adjusted. This can avoid the highly time-consuming infilling of the surfaces, and a significantly higher process speed can be achieved.

For controlled printing in curves and corners, as well as at position jumps without material discharge, the output rate must be controlled depending on the path velocity. Because of the sluggish plastication behavior of an extruder, it is not useful to perform a volume change via the extruder speed. An upstream unit for a velocity-dependent material output of between 0 and 100 % has been developed. The patent-pending unit is currently undergoing testing and permits both the familiar path control of classical FLM processes and the manufacture of complex structures as a genuine 5-axis 3D printing process.

Typical Application: Fiber-Reinforced Vacuum  Clamping Fixtures

CFRP components are generally manufactured with near-net-shape, so that they only need to be machined at the component edge and for functionalization, for example to introduce bores or recesses. Because of the usually open and large-area part design, they are very unstable and, despite the high stiffness, tend to oscillate, which has a negative effect on the tool life and part quality, for example the dimensional stability and edge quality.

In order to avoid such effects in the end processing, the development partners used the SEAM process to produce a special vacuum clamping device, for processing CFRP components, on which the parts lie in full contact and can be clamped with low vibration by means of vacuum. In the example shown here (Title figure), this is a B-column segment with the dimensions 800 x 200 x 3 mm.

In general, the advantages of additive manufacturing lie in the fast and economic manufacture of individual end products, which permit the simple integration of functions such as vacuum fields or milling and suction channels. The targeted introduction of hollow structures additionally permits significant weight savings, which lead to greater material efficiency, shorter printing times, easier handling of the clamping means.

The printed vacuum clamping fixtures can be recycled back to the starting material for reprocessing into plastic pellet stock after their useful life is over, so that the concept of a closed loop system can be applied and, on the other hand, the logistics chain is simplified (Fig. 3). If there is subsequently a need for spare parts production, the shape can be rapidly and inexpensively recreated – there is no need to keep molds in storage for many years.

The SEAM process developed at the Fraunhofer IWU expands the possibilities for the efficient manufacture of plastic components by 3D printing. Thanks to the low material costs and the short manufacturing times, the part costs can be reduced to a fraction. The process also permits the additive processing of materials that could not be processed in this way until now, while achieving the same surface qualities as for the standard FLM process.

In addition, the SEAM process is suitable for manufacturing large structures. For this purpose, early developments have already started, for example for manufacturing large-format laminated molds and processing devices for large-area fiber composites. To this end, an extrusion unit is integrated into a portal movement system and thus achieves a construction volume of several cubic meters. Overall, the new process could represent a crucial step in increasing the efficiency of 3D printing processes.

Vacuum clamping fixture of a B-column segment, manufactured by the SEAM process 

Fig. 1. SEAM-Hex machine with extrusion-based plasticating unit and Hexapod 6-axis parallel kinematics

Fig. 2. PentaSEAM machine with Metrom 5-axis parallel kinematics and extruder die

Fig. 3. Closed-loop concept with the example of the vacuum clamping fixture

Metrom - Hauptartikel

Dipl.-Ing. (FH) Johannes Blase is group leader and Dipl.-Ing. (FH) Christopher John is research assistant in the department group of extrusion-based 3D-printing at the Fraunhofer Institute for Machine Tools and Forming Technology in Chemnitz, Germany.

Dr.-Ing. Martin Kausch is Department Head at the Fraunhofer IWU; <a href="mailto:martin.kausch@iwu.fraunhofer.de">martin.kausch@iwu.fraunhofer.de</a>

Dipl.-Ing. IWE Marcus Witt is Head of Technical Sales at Metrom Mechatronische Maschinen GmbH, Hartmannsdorf, Germany; <a href="mailto:marcus.witt@metrom.com">marcus.witt@metrom.com</a>

The two machines – the fastest 3D printers in the world (SEAM-Hex), according to the Fraunhofer IWU, and a Metrom machine for additive-subtractive processing (PentaSEAM) – can be seen live in action at Formnext in Frankfurt/Main, Germany, from November 19 to 22, 2019.

Anlagen Additive Fertigung / 3D-Druck, andere

3D-Drucker (für FDM, FFF, etc.)

Anlagen Additive Fertigung / 3D-Druck, Metall

Faserverbundwerkstoffe

Andere Werkstoffe

Sanitary Prototypes with  High Requirements

Geberit: „Selective Laser Sintering Really Sparks our Imagination“

In order to minimize the development time for new products, Geberit International AG manufactures many prototypes using 3D printing. Since 2016, the Swiss company uses a Sintratec S1 for design optimization and material testing in its prototyping laboratory. A visit to Switzerland.

The Geberit Group, the market leader for sanitary parts in Europe, operates 29 production plants in over 50 countries. Before the Group releases a new product for market launch, it must meet a variety of requirements. At the Group headquarters in Rapperswil-Jona, Switzerland, all prototypes are tested for quality, functionality, design and ease of assembly. Development engineers from various departments benefit from the modern prototyping laboratory. It allows them to implement their ideas within a short time.

Before mass production (e. g. injection molding), each component undergoes several design variants. A considerable number of professional devices are available in Geberit’s prototyping laboratory with a wide range of 3D printing processes. A total of around 16,000 parts are printed each year – by selective laser sintering (SLS), fused deposition modeling (FDM), stereolithography (SLA), binder jetting (3DP) or multi jet fusion (MJF).

One of these components was a flexible sheathing of a valve connection angle (Fig. 1) for installation in confined spaces. Roger Baggenstos (Fig. 2), Geberit development engineer in the Piping Systems division, develops special solutions such as this: “Supply systems are insulated so that as little heat as possible is radiated from the hot water pipe to the cold water pipe – in that way, the hot water remains warm and the cold water cold. This is also necessary to comply with the normative requirements. For the valve connection angle as an example, we use expanded polypropylene, EPP for short.” The foamed plastic is stretchable and mechanically strong at the same time.

Such hygiene requirements generally affect the design of the water supply lines. Today, these are designed to keep the pipe distance with stagnant water as low as possible. In the past, for example, one separate pipe each led to the washbasin, one to the toilet and one to the shower, while today the line is continued directly from one installation to another.

Instantly Available Functional Prototypes

Back to the EPP sheathing: Geberit uses selective laser sintering (SLS) to produce functional prototypes with largely similar properties to such a sophisticated component. The coating was printed with the flexible Sintratec TPE material on the Sintratec S1 SLS desktop printer (manufacturer: Sintratec AG, Brugg, Switzerland; Fig. 3) and immediately tested in a real construction situation. Thus, Roger Baggenstos and his team were able to check whether the product idea really was mountable. With success: the two sheathing parts could be moved around the fitting connection angle without any obstacle and fixed onto it by means of the required snap mechanism.

Hugo Arnold, Head of the prototyping laboratory at Geberit, looks back on the project: “Prototypes produced with other 3D printing processes did not show the required flexibility and mechanical strength. The decision to manufacture the components on the Sintratec S1, however, depended on other factors.” Interestingly, the large SLS systems proved to be impractical for the project due to their complex material change processes: “On the Sintratec S1, which has a small printing area, I can immediately carry out a test print with relatively little powder,” continues Hugo Arnold. So, printing small individual parts on large-scale SLS systems is impractical.

3D Printing Has Largely Replaced Conventional Methods

That SLS systems like the Sintratec S1 create competitive advantages is also confirmed by Roger Baggenstos, who had only little development time available for this project: “We appreciate the fast implementation possibilities of test components. With the printed prototype in hand, we can immediately evaluate its function together with our production partner.”

With the durable Sintratec PA12, Geberit prints objects such as water housings, distributors or test specimens that can withstand water pressure up to 48 bar. Geberit uses the flexible Sintratec TPE material for seals on illustrative models, sound insulation parts (for the decoupling of water noise) or thermal insulation parts. In order to satisfy the developmental curiosity of engineers and laboratory personnel, tests with foreign materials are also carried out with the Sintratec S1. Hugo Arnold comments: ”For such research applications, we evaluate ten to twenty parameters per day.”

Geberit had already purchased the first 3D printer in 2005. While lathes and milling machines still made up the majority in the prototyping laboratory at that time, 3D printers dominate today. Selective laser sintering is one of the most commonly used technologies. Roger Baggenstos summarizes: “Thanks to SLS, we benefit from an easier idea generation in product development. The feel of 3D-printed objects sparks our imagination and enables us to quickly optimize designs and thus significantly reduces time-to-market.”

On the left the prototype of the valve connection angle made of Sintratec TPE and on the right the series component made of EPP

Fig. 1. For this fitting connection angle, the prototype of the flexible sheating was processed with a laser sintering system and tested in this real construction situation

Fig. 2. Roger Baggenstos, Geberit development engineer in the Piping Systems division: “We appreciate the fast implementation possibilities of test components

Fig. 3. Printed from Sintratec TPE material, heat-insulating and snap-in: functional prototype of a flexible jacket

Geberit - Hauptartikel

Luca Meister is a freelance journalist and lives in Zurich, Switzerland; <a href="mailto:textbuffet@protonmail.com">textbuffet@protonmail.com</a>

Anlagen Selektives Lasersintern, Kunststoff

Rapid Prototyping

Werkstoffe für additive Verfahren

Leonhard Kurz Has Extended its Development Capacities with Injection Molding Systems from Wittmann Battenfeld.

The company Leonhard Kurz is a specialist in the development and production of decorative and functional coatings for plastics applications, which are applied by means of carrier foils during injection molding. Essential objectives of the company are technology and process development as well as the optimization of the 3D foil forming around corners and the contours of the plastic parts. For this purpose, Kurz operates an extensive injection molding technology center. New in the machinery: two production cells based on servo-hydraulic injection molding machines from Wittmann Battenfeld.

For many of us, the car has become like a second living room, where we tend to spend more and more of our time, thanks to the increasing traffic density. As compensation measures against the stress factors of mobility, car manufacturers have increasingly invested in recent years in ergonomic improvements and assistance systems, but also in a more comfortable environment for the driver, especially through improving the surrounding surfaces. This includes coating of hard cladding parts with soft-touch elastomers, as well as painting and printing effects or combining structural parts with surface decorations. The latter, in particular, has turned out to be the method with the greatest potential for innovation, thanks to the advancement in foil technology, which is proved by significant growth rates.

Ever since the 1980s, foils have been playing an increasingly important part in the surface finish of plastic parts. At first, these were mainly used as carrier foils for metallic structures to be transferred onto plastic parts by hot stamping. This led to the foil gaining an increasing significance as a transfer medium for placing design layers/decorative prints on parts during the injection molding process. According to the company, Leonhard Kurz Stiftung & Co. KG, Fürth, Germany, is the market leader in transfer products for the surface finishing of plastics parts. It develops and produces decorative and functional coatings for a wide variety of plastic applications.

More than just High Gloss, Decoration and Scratch-Protection

For applying the print decor layer Kurz uses the roll-to-roll transfer (IMD, in-mold-decoration). A foil feeder specially developed by Kurz pulls the laminated foil web (most frequently consisting of polyester) synchronized with the cycle through the open mold, with the possibility of having continuous designs controlled by path control, and single image decorations by light conductor positioning. The IMD mold-specific clamping frame and vacuum technology then take care of high-precision holding and fitting into the mold cavity.

The carrier foil is subsequently backmolded. The decorative layer on the carrier foil is specified to form an adhesive bond with the plastic. After the carrier foil has been separated from coating layer during mold opening, the decorated part is demolded normally. This decoration method is also known as a “dry varnish decoration system” (including protective coating).

In addition to traditional hot stamping foils and IMD foils, Kurz offers a wide range of decoration products with special effects and/or functionalities (Fig. 1), such as parts commonly known as PMD (print mold design) foil components. These are crystal-clear polycarbonate foils printed on both sides with precisely matched designs, thus creating decorations with a 3D effect.

Due to their relatively high rigidity and softening temperatures, however, PC foils are not suitable for direct processing on an injection molding machine, but must be cut to size and formed into insert parts outside the machine by thermoforming and subsequent downstream finishing steps instead. When inserted into the mold and then overmolded, they are transformed into instrument panels of center consoles for automobiles.

Varioform IMD Pushes Application Limits and Unit Costs

However, neither the IMD roll passage method for processing polyester foils nor the PMD foil insert process are all-purpose solutions for decoration tasks. They differ in terms of both application limits and costs. For instance, the IMD polyester foils processed directly from the roll within one injection molding cycle can only be drawn three-dimensionally within relatively narrow limits.

As a further step towards realizing three-dimensional design transfer, Kurz intelligently combined several methods to a single process resulting in the Varioform roll-to-roll IMD process. This involves decorating, forming, back injection molding and punching directly in the injection mold combined with a single-step-injection molding process.

Martin Hahn, responsible for Application, Technology & Innovation, explains this as follows: “This additional technological development in application technology opens up a wide range in the choice of foil systems in combination with the injection molding substrate materials (such as PP or ABS-TPU). This leads to new variation options in the construction of moldings and opens new diversified design perspectives as well as, from an economic point of view, to achieving an even greater 3D moldability”.

Similar to standard IMD processes, design changes can be carried out by simply exchanging the foil roll. It is also possible to process a great variety of single image and continuous decorations as well as functional foils. This, too, enables the realization of extremely high-quality surface designs at reasonable cost. Thus “IMD Varioform” constitutes a further offer in Kurz application technology.

For Kurz, processes and application technology are vital success factors. “Accordingly, our technical application lab for injection molding has been extended by adding appropriate trial and testing equipment. Following a comprehensive cost/benefit analysis, we decided to acquire two injection molding cells from Wittmann Battenfeld for this purpose”, explains Hahn. The decisive argument in favor of this choice was their “all-in-one” concept, which means that all auxiliary components for the injection molding machines, such as handling robots, parts conveyor systems, material loaders, mold tempering devices and the local cleanroom-cell come from the Wittmann Group, and are therefore perfectly matched and linked to each other and to the company environment via the Wittmann 4.0 software tools.

To drive the process development with maximum practical relevance and production maturity, Kurz decided to acquire two machines from the servo-hydraulic SmartPower series, namely a SmartPower 210/750 (with 2100 kN clamping force) and a SmartPower 120/350 (with 1200 kN clamping force), each equipped with a W918 robot from Wittmann and clocked part conveyors. Kurz has fitted the clamping unit of each machine with a roll-to-roll foil feeding unit (Fig. 2)

Project Leader Fabian Bürkel from Kurz and Marcus Otto, Sales Engineer for Injection Molding Technology at Wittmann Battenfeld in Nuremberg, Germany, were jointly responsible for the detailed conception of the two systems (Fig. 3).

Bürkel comments in retrospect: “The most important point for us was the transferability of the processing parameters established in test runs to the real operation practice of potential users of our foils. Here, we wanted to be as independent as possible of variable influences from production auxiliaries. The Wittmann Battenfeld concept of interlinked auxiliary devices puts us in the position to concentrate entirely on the injection molding process with the corresponding wide range of different foil systems”.

Reaching for Higher  Three-Dimensionality

The main focus of the new testing capacities lies on increasing the level  of three-dimensional foil stretching (through infrared pre-heating and subsequent vacuum forming inside the mold) as an integral part of the injection molding process, as well as systematic optimization of the sprue position to minimize the effect of shear strain from the plastic melt on the higher elastic foil. An important side effect of the current product development program is keeping the corners of molded parts free of wrinkles, as well as process-safe folding of the foil around the contours of the molded part. Folding in this context means bending a decorative material around the edge of a carrier part by 90° or 180°, with subsequent fastening of the bent edge of the foil to the rear side of the carrier part) (Fig. 4).

An award-winning application for a car door interior cladding demonstrates the potential inherent in Kurz application processes (Fig. 5), which was presented live in production in a similar way at the Wittmann Battenfeld booth at K 2019. Here, a partly translucent decorative foil (IMD single image system) is combined by means of IML technology with a printed capacitive sensor from PolyIC GmbH & Co. KG, Fürth, Germany, on the inside of the molded part. Both of these are backmolded within just one injection molding cycle. The sensor enables touch operation of the light switch and the dimming function, by which the color of the LED light source can also be varied.

Decorative and functional coatings, such as those developed and produced at Leonhard Kurz in Nuremberg/Fürth, Germany, enable efficient implementation of new design concepts, shown here, for example on a car door panel with variable and dimmable backlighting

Fig. 1. PMD insert combined with a printed capacitive PolyIC sensor on the inside of the molded part 

Fig. 2. Both injection molding machines are equipped with roll-to-roll foil feeding units.  The robots carry a foil heating panel and on the opposite side a suction gripper for finished  parts removal

Fig. 3. The production cells were designed by Kurz Project Leader Fabian Bürkel and Marcus Otto, Sales Engineer for Injection Molding at Wittmann Battenfeld

Fig. 4. Examples from the current testing program at Leonhard Kurz to extend the thermoforming dimensions and potentials for forming corners and radii with various foils

Fig. 5. The back of the car door panel – the visible side is decorated using the IMD process – contains a prefabricated foil component from the Kurz group-company PolyIC with a printed-on sensor structure that integrates the interactive light switch and dimming function

WiBa - Hauptartikel

Dipl.-Ing. Reinhard Bauer is a freelance technical writer for plastics engineering; <a href="mailto:office@technokomm.at">office@technokomm.at</a>

Spritzgießen

Kunststoffverarbeitung: Verfahren

Spritzgießmaschinen, allgemein

Kunststoffverarbeitung: Maschinen und Komponenten

Spritzgießmaschinen

Kapazitive Sensoren

Messtechnik

Sensoren / Messwertaufnehmer

Folientechnik (IMD, IML, FIM, u.a.)

Spritzgieß-Sonderverfahren

Glittenberg Supplies Tools for Vital Medical Devices to Celon Pharma

A Polish pharmaceutical company is developing inhalation therapy for the treatment of lung disease and the appropriate drug delivery drug. The inhaler has a complex interior and consists of 14 components. In order to be able to produce these with the required precision, Celon Pharma has formed a partnership with the mold making company Glittenberg and its hot runner sister Witosa.

Mostly detached from developments in other industrial sectors, medical technology continues to be a rapidly growing industry with great innovative strength. Diverse new products with new types of materials for a wide variety of applications offer a wide range of applications, in particular for the field of injection molding technology. Anyone who wants to play here, however, faces great challenges, and not only in terms of quality, innovation and cost efficiency. More than anything, the rules and regulations applicable in this sector must also be mastered.

Compared to other industries, the quality requirements are very high. The documentation requirements are extensive. Production in accordance with GMP (Good Manufacturing Practice) is mandatory. This requires permanent monitoring and compliance with hygiene regulations and complete documentation of all process data over many years. Entry into the medical technology industry as a supplier is therefore difficult and requires a great deal of effort.

Development of an Inhaler for an Enzyme Inhibitor

The Celon Pharma S. A. is a still young pharmaceutical company based in Kielpin near Warsaw, Poland. It was founded in 2002 by Marciej Wieczorek. Today, the company employs 400 people in Poland, including 70 scientists, and distributes medicines in more than 50 countries around the world. The great strengths of Celon Pharma are their extensive research and development facilities. The company has two fully equipped laboratories that develop pharmaceutical products for the treatment of cancer, neurological disorders, diabetes and other metabolic disorders. Another focus is on the development, manufacture and distribution of specialized generics.

The production sites of Celon Pharma have attained appropriate GMP approvals. The GMP certificate enables the company to obtain authorizations for sales and marketing of drugs in all EU countries. Existing quality standards for production are thereby guaranteed.

Celon Pharma launched the PIKCel project in 2014 as part of the EU funding program “European Regional Development Fund”. The aim of the project is to use a PI3K inhibitor, which is used to treat various types of cancer, also for the treatment of lung diseases such as asthma or COPD (chronic obstructive pulmonary disease). The method of administering this medicine is inhalation.

Sophisticated Mechanics with 14 Interrelating Components

As part of this project, Celon Pharma faced the challenge of developing and producing a fully functional discus inhaler (Title figure). The customer was requiring from the outset that all parts for the inhaler be manufactured with the highest precision and accuracy in order to ensure a completely reliable functionality. Deviations from the required dimensions and the maximum tolerance of ± 0.02 mm at the individual components of the inhaler are not permitted, since otherwise the function is impaired.

For example, when operating the inhaler, the blister must be transported exactly to the next medication reservoir, opened, the used conveyor belt wound up and the unused stored. The drug must then be completely pulled out of the opened blister and transported through the mouthpiece by a slight negative pressure, as it arises when inhaling a small child. On the other hand, during handling of the inhaler, the drug must not fall out of the reservoir of the blister prior to inhalation.

In this complex mechanism, a total of 14 components work perfectly together to bring the inhaler into the desired function. An absolutely clean and smooth functioning of all moving components is a prerequisite. Failures or contamination, for example due to material abrasion, are not permitted.

“The demanded precision for the exact interplay of all parts of the inhaler, which must also remain absolutely constant over a planned serial number of 400 million units per year was one of the yardsticks that we set when choosing a suitable tool manufacturer and hot runner manufacturer, “says Artur Wieczorek, Project Manager at Celon Pharma. The fully automatic assembly and assembly of the inhalers in the cleanroom (Fig. 1) should not affect product quality.

The highest uniform quality and hygiene standards based on validated processes and a certified QM system were another basis. In addition, there were the regulations prevailing in medical technology such as the GMP requirements that require the implementation and exact documentation of risk assessments for the injection molding tools. In other words, qualification and process validations must be performed to create and document appropriate process capability certificates.

With this ambitions, Celon Pharma went in search of a suitable partner in Poland and Germany and then approached the Glittenberg Group. Artur Wieczorek (Fig. 2): “The subject of plastic injection molding was completely new to us. We had an inhaler in our hands and in no time needed millions of them. Therefore, short communication channels at this stage were very important to us. We needed a professional partner who could immediately implement our request and offer everything – design, tools, hot runner systems – from a single source. “

The time frame for this project was very tight: 14 injection molding tools including the hot runner systems had to be completed in less than a year, based on the article. Added to this were the high quality requirements for the tool surfaces, which are particularly demanded by the US market. “Since we are at home in the medical technology industry, we saw from the outset the enormous effort that we had to put into planning the tools in order to be able to fulfill the guidelines of the industry,” says Torsten Glittenberg, Managing Director of the Glittenberg Group.

Based on the requirement specifications and the performance specifications of the customer, a corresponding product specification was then drawn up and, in particular, determinations for the cleanroom suitability of the injection molding tools and hot runner systems were made. Among other things, this involved the selection of suitable corrosion-free materials for the tools and hot runners. But also maintenance and inspection plans and specifications for cleanroom-compatible cleaning, lubrication and storage of tools were created.

Despite the major hurdles, all deadlines were met and sometimes even undercut. “The design of the article and the documentation were very well prepared by Glittenberg,” says Wieczorek. And so already in 2014, the first parts could be produced from the new tools. These were optimized in several design loops and adapted to the required strict article geometries.

The first inhalers were intended for the US market. In 2016, production started for the entire European market with an initial volume of one million units. Meanwhile, the inhaler has gone through the tenth design loop. “We have grown with the demands of the market. Glittenberg was always open when help was needed and ready for adjustments. The desired changes were implemented in a completely uncomplicated manner “, Project Manager Wieczorek assesses the cooperation with his tool supplier.

Meanwhile, 35 injection molds equipped with hot runner systems and over 300 hot runner nozzles from Witosa have been delivered to Celon Pharma (Fig. 3). Under cleanroom conditions, the components for approx. 12 million inhalers per year are manufactured on 16 injection molding machines, then, fully automatically assembled, provided with blisters and tested.

Celon Pharma is currently running twelve drug development programs funded by the European Union. One special field of research in this program is the administering of the drugs by inhalation. A current program called “Disc” aims to develop this method of administering the drug for treating depression by means of an already known anaesthetic. While currently available depression treatments show therapeutic effects only after a few weeks of regular medication, several clinical studies have demonstrated a direct and long-term antidepressant effect of the anaesthetic. Patients should be able to take the drug themselves and control the dose administered, thanks to the developmental experience of Celon Pharma.

Because of the foreseeable enormous increase in demand of the order of 400 million units per year, Celon Pharma now plans to use further high-cavity tools for very fast cycles. Torsten Glittenberg is confident that “in this case we will be able to meet all the requirements of the medical technology industry. Even though that is sometimes very complex.”

Fig. 3. Celon Pharma usually uses DT-16 nozzles with an open nozzle tip or with a needle valve. This series is particularly suitable for products with small shot weights and tools with high numbers

For its complex functional mechanism, the inhaler requires 14 components

Fig. 1. The inhalers are fully automatically mounted in the cleanroom

Fig. 2. Artur Wieczorek (right), Project Manager at Celon Pharma, together with Ravan Graubner, Sales Manager International at Witosa Hot Runner Technology

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Ravan Graubner is Sales Manager International at Witosa GmbH, Hot Runner Technology, Frankenberg, Germany.

The company group Glittenberg, based in Frankenberg in northern Hesse, Germany, was founded in 1990. It consists of the companies Formenbau Glittenberg, Kunststofftechnik Glittenberg and Witosa Heisskanalsysteme. The group now employs over 150 people and is represented worldwide with its products.

<a href="http://www.glittenberg-gmbh.de">www.glittenberg-gmbh.de</a>

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The Qualification of Suitable Foam Injection Molding Processes Enables the Use of Thermosets in Lightweight Construction Applications

The transfer of foam injection molding from thermoplastic to thermoset processing has not yet been implemented in industrial practice. IKV Aachen has investigated this transfer and has precisely analyzed the economic efficiency of the process and the potential for lightweight construction.

For years, politicians have been urging the automotive industry to reduce the CO2 emissions of its fleets – and thus above all the vehicle weight – [1–3]. At the same time, a trend towards increased temperature resistance of materials in the engine compartment is emerging, which is why high-temperature-resistant or stabilized plastics are increasingly coming into focus [4]. These can meet the higher temperature resistance requirements and at the same time have a significantly lower density than metals (e. g. PA66-GF30: ~1.4 g/cm³, steel: 7.9 g/cm³).

Compared to high-temperature thermoplastics, such as polyphenylene sulfide (PPS) or polyetheretherketone (PEEK), which combine high operating temperatures with good mechanical properties [4], thermoset molding compounds with similar properties are considerably less expensive. They are therefore increasingly at the focus of technical series applications [5–7]. However, thermoset molding compounds have a higher density (EP ~1.9 g/cm³) than their high-temperature-resistant thermoplastic counterparts [8]. Their high density is a major disadvantage for use in lightweight construction applications. In particular, the excellent thermal and chemical properties as well as the low processing shrinkage favor the use of thermosets for applications close to engines.

In order to reduce the weight of the molded part, it is possible to foam plastics. Thermoplastic foam injection molding (FIM) is an established process in industry. A foam structure is created in the molded part by pressure relief of a propellant gas dissolved in the molten plastic during molding. In addition to weight reduction, this process offers further advantages. Foaming achieves a homogeneous holding pressure effect, since the formation of gas bubbles creates a pressure directly in the produced component. Furthermore, the addition of the blowing agent reduces the viscosity of the mixture; this in turn enables lower injection pressures and longer flow paths.

Despite this potential, a transfer of FIM to thermoset processing has not yet been implemented in industrial practice and has been barely investigated from a scientific point of view. For this reason, the aim of this research is to qualify and analyze suitable processes for the foaming of thermoset molding compounds.

Physical foaming of plastics is based on mass transport processes of the blowing agent in the plastic. These are stimulated by concentration or partial pressure gradients [9]. In order to test the sorption behavior of pourable thermosets, IKV – the Institute for Plastics Processing in Aachen, Germany, – has carried out high-pressure sorption measurements for loading epoxy resin molding compounds (EP) with CO2. The results show that, after a loading time which is clearly above economically reasonable cycle times (> 60 min), only an insufficient gas concentration of &lt; 1 % is achieved.

The reason for this are the high filler contents of thermosets, which form diffusion barriers and thus only permit slow sorption speeds and low sorption capabilities. Thus, physical foaming cannot be usefully transferred to thermoset processing.

In contrast, thermosets can be chemically foamed because no major modification of the plant engineering is required. The chemical blowing agent is mixed as a powder with the thermoset molding compound and fed into the injection molding machine. During injection into the hot mold, the reaction temperature of the blowing agent is reached and it is released, forming a foam structure. This is fixed by the parallel crosslinking reaction (Fig. 1).

Since both the crosslinking and the blowing agent reaction are thermally activated, special attention must be paid to temperature control when planning the experiment. In addition to the temperature of the mold and the nozzle of the injection molding unit, the blowing agent content and the injection speed are also varied. The materials used are an epoxy resin molding compound (type: Epoxidur EP 3582; manufacturer: Raschig GmbH, Ludwigshafen, Germany) and an endothermic chemical blowing agent (BIH, type: Hydrocerol BIH; manufacturer: Clariant Plastics & Coatings (Deutschland) GmbH, Lahnstein, Germany).

An alternative approach to density reduction is the use of hollow glass spheres (HGS). These have a lower density than the molding compound and thus reduce the density of the components. One advantage of using hollow glass spheres (as in chemical foaming) is that neither the plant nor the process has to be modified. The density reduction can be adjusted via the hollow glass sphere content. It is important for process control that the shear in the injection molding process does not exceed the compressive strength of the hollow glass spheres.

For this reason, the processing parameters vary not only the content of hollow glass spheres (HGS, type: iM30k; manufacturer: 3M Deutschland GmbH, Neuss, Germany) but also the screw speed, the injection speed and the nozzle temperature. The matrix material used is a phenolic resin molding compound (type: Bakelite X22; manufacturer: Hexion GmbH, Iserlohn, Germany), which is suitable for additional fillers due to its higher resin content.

The trials are carried out on an Allrounder 370A – 600 injection molding machine (manufacturer: Arburg GmbH + Co KG, Lossburg, Germany) equipped with a thermoset unit (compression-free screw conveyor, D = 30 mm, L/D = 15). The test specimen is a plate with the dimensions 80 x 80 x 4 mm, from which specimens for the tensile test and unnotched specimens for determining the impact strength are milled out (Fig. 2).

The foaming effect of the chemical blowing agent results in a weight reduction of the thermoset test specimens. In order to analyze the influences and interactions of the process parameters, the component weights are statistically evaluated (Fig. 3, left). Despite an increasing standard deviation, a significant weight reduction of up to 21 % (related to compact test specimens) can be observed with the addition of 10  wt. % blowing agent. Furthermore, the evaluation shows no further statistically significant effects or interactions of the varied process parameters.

Analysis of the mechanical properties shows that the foam structure causes the properties to drop disproportionately to the weight reduction achieved (Fig. 3, right). Compared to the compact reference samples, the stiffness is reduced by up to 25 %, while the strength and impact strength of the foamed samples are only half the initial value.

After microscopic examination of the fractured surfaces, inhomogeneous foam structures in the cross-section of the test specimens turned out to be the main cause. The inhomogeneous distribution of the blowing agent leads to areas with agglomerated gas bubbles which act as defects in the material and thus explain the failure of the test specimens. The decrease of the mechanical properties should be evaluated critically, but does not directly represent a knockout criterion.