With integrated process chain, high strength and media tight plastic/metal hybrid components can be produced from laser-structured metal semifinished products.

Three stages of the manufacturing process of a headlamp reflector. From left to right: die cast reflector insert, back-molded hybrid reflector, reflector after PVD coating.

16:9

Hybridtechnik

Kunststoffverarbeitung: Verfahren

Spritzgießen

Magnesiumlegierungen

Metall Werkstoffe

NE-Metalle

Beschichten (CVD, PVD)

Oberflächentechnik

Chemisches Bearbeiten (Auftragen)

Aluminiumlegierungen

Leichtbau

Lichttechnik

Laserstrukturieren

Laserbearbeitungen

Polycarbonat

Kunststoff Werkstoffe

Thermoplaste

Form-Fitted Hybrid  Lightweight Construction

Zahoransky supplies systems and injection molds for manufacturing breakage-proof primary packaging for pharmaceuticals. Three typical applications.

The double quick-change system for pipette tips permits rapid restart of production after brief maintenance interruptions.

Automatisierungszellen

Automatisierungstechnik

Spritzgießwerkzeuge

Kunststoffverarbeitung: Maschinen und Komponenten

Werkzeuge für die Kunststoffverarbeitung

Medizintechnik

Medizinprodukte

Pharmaceutical Primary Packaging  with No Risk of Breakage

Once again, the K 2019 in Düsseldorf, Germany, lived up to its claim to be the leading trade show for plastics technology. At least in the field of injection molding, there were exciting global innovations to see – if you looked closely.

Fig. 1. Smart Operation – the machine is operated with only four buttons (© KraussMaffei)

Injection Molding Trends at K 2019

Schaumspritzgießen

Smart Factory

Energieeffizienz

Mikrospritzgießen

Mehrkomponenten-Spritzgießen

Spritzgießmaschinen, allgemein

Spritzgießmaschinen

Fließpressen

Handling, Handhabungstechnik für die spanende Fertigung

Handling, Handhabungstechnik

Spritzgieß-Sonderverfahren

Spritzgießsimulation

Software

Simulation

Elastomer-Spritzgießen

Linearroboter für die Kunststoffverarbeitung

Industrieroboter

Montagetechnik

Industrie 4.0 für die Kunststoffverarbeitung

Industrie 4.0

Montage-Spritzgießen

Knickarmroboter

Co-Injektion (Barriere-/Sandwich-Spritzgießen)

Hybrid-Spritzgießen (Metall / Kunststoff)

Ressourcenmanagement

Produktion

Technical Excellence thanks  to Digital Assistance

The imminent paradigm shift in mobility makes it essential that the German automotive industry prepares itself to undergo a transformation, both now and in the future, the like of which has not been seen before. Resource-efficient lightweight system engineering in a multi-material design is a key differentiating feature here. In this connection, novel materials, highly automated, digitized manufacturing processes as well as functional integration for intelligent component structures and vehicle systems will form the basis for creating springboard innovations that will dominate the competition. 

Innovative Injection Molding Technologies for Hybrid Lightweight Applications 

Elektromobilität

Verbundwerkstoffe / Werkstoffverbunde

Magnesium

Faserverarbeitung

Warmformen / Thermoformen

Inserttechnik

Beschichten von Metallen, allgemein

Verbindungstechnik, hybride

Plastic and Metal − an Inseparable Team 

In the Federal German Excellence Cluster "Merge", new processes for hydroforming-injection molding for processing thermoplastic fiber composites are being researched. With gas as a forming and supporting medium, fiber-reinforced plastic tubes have been processed for the first time. In specific applications, researchers succeeded in reducing the part weight and process costs, and increasing productivity. 

A Merger of Hydroforming and Injection Molding Technologies Is Driving Lightweight Design 

Kunststoff-Profile

Towards the Functionalized FRP Tube 

Aside from offering high mechanical strength, versatility and durability, polymer materials are ideal for applications in the electrical industry because of their ability to isolate electrical current.

For the conduction cooled MicroTCA systems, Harting processes LCP, a material that is flame-resistant, dimensionally stable at high temperatures, chemically resistant, and has only a low thermal expansion

Connectors for Industrial Lifelines: High-Tech Injection Molding at Harting

Polymere, flüssigkristalline

Heißkanalsysteme

Komponenten für die Kunststoffverarbeitung

Stanzen

Verfahren für die spanlose Fertigung

Schneiden

Steckverbinder

Elektromechanik

Well-Balanced Hot Runner Technology for LCP Processing

The interplay between the physical and virtual process chain permits the fully automatic production of FRP-metal hybrid parts every minute.

Virtualization offers great potential for better understanding of complex manufacturing processes for hybrid parts and shortening development times. The digital twin, in combination with the recorded process parameters of the physical process chain, is intended as an efficient tool for virtual design and optimization for future hybrid processes.

From Simulation to Mass Production of Hybrid Parts

Organobleche (gewebeverstärkte Thermoplast-Halbzeuge)

Halbzeuge und Zwischenprodukte

Kunststoff-Halbzeuge

With an Automated Process Chain  and a Digital Twin

In the production of plastic parts for the medical and pharmaceutical industry, the requirements for cleanroom environments are becoming increasingly stringent. In this area, not only the demand for all-electric injection molding machines is increasing. There is also an increasing use of electric drives for the implementation of mold movements, which meet the high requirements for cleanliness and reliability.

Fig. 1. Solutions for electrical mold movements, for example a 72+72 cavity stack mold for the closing cone production

Electrical Drives in Injection Molds

Elektrische Antriebe

Antriebe

Mess- / Regel- und Prozessleittechnik

Prozessautomation

Mess-, Steuer- und Regelgeräte

Qualitätssicherung

Qualitätssicherung Kunststoff

Reinraumsysteme / -technik

Mold Technology

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.

For its complex functional mechanism, the inhaler requires 14 components

Glittenberg Supplies Tools for Vital Medical Devices to Celon Pharma

Plastic in the Service of Medicine

Pipette tips feature a challenging wall thickness/length ratio, an inner geometry that is key for analysis results, and a tip opening just a few tenths of a millimeter wide. They have been in extremely high demand during the coronavirus pandemic, which is why the mold construction and hot runner specialist Männer has developed a mold with an innovative cluster concept.

At the Männer test center in Bahlingen, Germany: an injection mold for manufacturing pipette tips, shown here in operation. Automation of the system is currently being set up

Pipette Tips: Männer Presents a Mold with Replaceable Clusters

Maintenance During (Nearly)  Uninterrupted Production

Under the new name and the umbrella of the Indian Vasatha Group, the former KTW-Werkzeugbau is thriving in Waidhofen, Germany.

In the VTW pilot plant, the molds have been sampled to date. In future, it will also receive customer systems for start-up series.

Like a Phoenix from the Ashes

Injection molding machines are doubtless complex high-tech products. Despite this, their significance for injection molding should not be overrated. Only the appropriate combination of machine, mold and process provides the necessary framework for cost-efficient production. Combined processes are becoming increasingly important here. 

Injection Molding Trends: The Age of Combined Processes is Dawning 

Lightweight construction, small batches, and progressive integration of electronic functions: general industrial trends are spilling over into the injection molding industry. Recent years have seen the development of remarkable solutions for meeting all kinds of requirements. Machine manufacturers have not been idle though: precision-regulated processes form the basis for many applications, and now it seems that the self-optimizing injection molding machine is no longer a fantasy. 

Visible and Invisible Innovations Continue to Confer Benefits on the Industry.  And on Mankind, too? 

Steuern, Regeln

Additive Fertigung

Metallpulver-Spritzgießen

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

Temperiertechnik

Nobel Prize for Injection Molding 

Every three years, the showcase of plastics technology, the K fair, takes place, where one can deduce the current state of the industry. What is occupying the experts today, and what will still be flourishing in the future? The following article describes some of the development paths and trends. At the end of the day, there is a lot of tried-and-tested technology that is being continually refined and improved. There were also some innovative and visionary applications to be seen. 

Industry 4.0 Comes to Injection Molding and True Innovations at K 2016 

Instandhaltung

Polyethylenterephthalat

Mehrfarben-Spritzgießmaschinen

Normalien und Heißkanaltechnik

Spritzprägen

Schäumen / Reaktive Verarbeitung

Optische Mess- und Prüftechnik

Injection Molding 4.0 – Visionary and Tried-and-Tested Solutions 

Four project partners showcased their companies at Fakuma last October by means of an ingenious give-away. Two of the companies involved ¿ Horst Keller Werkzeugbau and Hasco ¿ have already enjoyed a dependable working relationship for almost 50 years. They implemented the project, based on an idea by injection molding machine manufacturer, Dr. Boy, in a very short time, together with a third partner from their network. 

Four Companies Team up for the Joint "Check Card" Project 

Multifunctional Trade-Fair Give-Away 

Process Chain for the Production of Hybrid Medical Products

Combined Deep-Drawing and Backmolding Process with Mechanically Interlocking Joint

Pharmaceutical crimp caps generally consist of a thin aluminum sheet and a plastic component, and are used to seal medical vials, for example for vaccines. Through a combined deep-drawing and backmolding process with previous inline laser treatment of the thin aluminum sheet, the process can be significantly shortened. The media-proof joining together of the two materials is carried out through a mechanically interlocking connection.

Medical vials and small injection bottles are frequently sealed with so-called crimp caps. These consist of an aluminum component that guarantees a long-lasting seal and a plastic component that allows easy opening of the crimp cap. At present, both components are usually produced in separate processes and subsequently compressed together, which necessitates a large number of handling and cleaning steps as well as high machine and tooling requirements. At the same time, the potential of the individual materials and their interplay in the hybrid component are only utilized to a limited extent.

In order to reduce the manufacturing work and improve the product quality, a group of several companies and research institutes (Table 1) has developed a mechanically interlocking process for joining the plastic together with the thin aluminum sheet. In this process, undercut microstructures are incorporated through laser radiation into the metal component, which, during subsequent backmolding, serve as interlocking elements. The joining together of the two components is to be carried out in a combined deep-drawing and backmolding process, which offers high potential for automation (Fig. 1).

To do this, suitable laser structuring parameters have first to be identified in order to create undercut microstructures in the 200 µm thick sheet component. In addition, it has to be proven that deep-drawing of the structured sheets is possible, because the microstructure can considerably weaken the metal sheet because of its low thickness. The aim is to implement the combined process fully automatically in a pilot production cell.

The innovative joining technology, which combines the advantages of an interlocking joint and an adhesive joint, offers extensive potential for heavy-duty hybrid materials. Through the interlocking connection of the two materials, it is possible to dispense with adhesive agents or pretreatment, so that the choice of plastic component and its use in medical technology is no longer restricted. If the interlocking elements are small enough and arranged in high density on the surface, the connection between the materials can be assumed to be a quasi “full-area joint”. As a result – as with an adhesive joint – the load is applied homogeneously over the joining area. The laser microstructuring of the thin aluminum sheet should also enable a quasi “full-area” interlocking joint.

For the microstructuring of the metal surface by laser ablation, both continuous and pulsed radiation sources are currently used [1]. With high intensities (I ≥= 108 W/cm²) and the use of a continuously emitting radiation source, the material ablation is carried out predominantly by evaporation. With a structuring in the form of lines, the structural geometry is changed by a repetition of the process. Through the geometry of the resultant microstructure and its configuration, undercuts are created [2] into which the plastic melt can flow. The strength of the joint can be influenced by different structural configurations [3, 4]. Until now, this structuring approach has only been studied for material thicknesses > 0.7 mm, so that the distortion of the metal component through the structuring process could be neglected.

Compromise between Bond Strength and Aluminum Sheet Damage

The microstructures in this project are produced by the Fraunhofer Institute for Laser Technology (ILT), Aachen, Germany, with a Singlemode fiber laser (Rofin FL 020C, manufacturer: Coherent Inc.) in combination with an intelliScanse 20 scan head (manufacturer: Scanlab GmbH). The laser has a maximum output of 2 kW and, with the optical system used here, a beam radius of approx. 20 µm is generated. The laser beam is diverted by two mirrors in the scan head, whereby, for example, lines or circles can be created.

By varying the laser beam power P, the scan velocity v, the number of passages N, the structure gap and the structure orientation, the geometry of the microstructure can be influenced. The material for the sheet metal used here is an AlFeSi alloy (EN AW-8011 H44, manufacturer: Aluminium Féron GmbH & Co. KG). Increasing the scan velocity shortens the interaction time between the laser beam and the aluminum surface, and the proportion of evaporated material increases accordingly. Consequently, the burrs at the opening of the structure can be reduced and the reproducibility of the structure form increases (Fig. 2).

Because of the reduced material ablation, comparatively more passages are needed for the undercut. The aim of generating a structure with undercut at a depth of &lt; 100 µm was achieved in the project. This structure depth represents a compromise between high bond strength and minimum damage to the thin sheet.

Apart from the microstructuring for the hybrid product, pre-damage is introduced by laser radiation in order to expose the rubber stopper when using the medical vial and to achieve a tightness structure. The laser also cuts out the circular blank from the aluminum sheet. In this project, the laser process is automated by Pulsar Photonics GmbH. Pulsar additionally integrates a camera-based quality control into the laser treatment unit.

Deep-Drawing of Structured Thin Aluminum Sheet

For the combined deep-drawing and backmolding process, Siegfried Hofmann GmbH developed and manufactured a prototype single-cavity mold. This was put into operation at the Institute for Plastics Processing (IKV) in Aachen. Various mold components, namely the draw punch, draw die and blankholder, were designed according to the relevant standards. In accordance with DIN EN ISO 8362, a diameter of 20.3 mm was selected for the punch of the deep-drawing tool for crimp caps of nominal size 20 [5]. The circular metal blanks with a size of approx. 32 mm are fixed by means of a vacuum in the mold (Fig. 3). Subsequently, the clamping force is applied via a core puller and the forming process is triggered by the movement of the draw punch.

In order to evaluate the deep-drawing process of the structured thin metal sheet in advance, SimpaTec GmbH is simulating this procedure. It is analyzing in particular the influence of the microstructure and the process parameters on the deep-drawing in order to prevent selected parameters leading to failure of the structure during the deep-drawing process. Apart from that, an examination is made of how the deep-drawing process changes the geometry, for example the opening width of the microstructure. Summarizing, it was found that, in the middle range with a structure depth of approx. 100 µm, structured thin metal sheet with a thickness of 200 µm can be formed by deep-drawing without any negative influence on the microstructure. This is a prerequirement for backmolding the caps and thus for the production of the mechanically interlocking caps.

In the combined deep-drawing and injection molding tool, a slider concept is used to enable backmolding of the deep-drawn sheets and to seal the cavity against the draw gap. This is necessary because the clearance is larger than the thickness of the metal sheet component. In the single-cavity mold, a cold runner sprue gate is used. After the deep-drawing process, the mold is closed, whereby the cavity is sealed off by the slide bar. After the injection, the composite with the thermoformed sheet metal component is produced in the microstructures through solidification of the plastic component – in this case the copolymer PP PCGR40 (manufacturer: Sabic AG) (Fig. 1). The bond strength is first tested in a vertical draw-off test. In initial trials, the bond strength between two star-shaped configurated microstructures and a circular microstructure is varied (Fig. 4). With the star-shaped microstructures, the minimum structure gaps are 100 µm and 150 µm. The circular structure configuration has a structure gap of 150 µm. For all test specimens, the area of the joint is 78.5 mm2.

The star-shaped structure with a structure gap of 100 µm achieves, with a cumulated structure length of 518 mm – in other words the total length of the microstructures in the bond area – a draw-off force of 23.4 ± 4.4 N. By increasing the structure gap to 150 µm and thus shortening the cumulated structure length to 324 mm, the draw-off force falls to 15.2 ± 6.9 N. The circular structure (structure length of 429 mm) achieves a draw-off force of 27.3 ± 2.1 N.

The results show that, with the same structure type, the accumulated structure length correlates with the bond strength, because, with a higher structure length, more anchoring points are available in the joining surface. In addition, there is an influence of the structure configuration or the way the structure is oriented to the direction of load. Because of the thermal influence of the laser treatment and the low material thickness between the structures, the minimum structure gap cannot be reduced at will [6]. Here, further tests are needed to increase the bond strength.

It was possible with the prototype tool to demonstrate the feasibility of the planned process route. In the next steps, the combined deep-drawing and backmolding process is to be further automated under the leadership of KraussMaffei Technologies GmbH and implemented in a pilot production cell. The process will be transferred to a 4-cavity mold. At the same time, the draw-off force of the plastic component is to be further increased. For this purpose, further variations of the laser structure configuration and process parameters of the injection molding process are to be carried out at IKV in cooperation with the ILT. Finally, Röchling Medical Solutions SE will validate the produced crimp caps.

[1] Poprawe, R.: Lasertechnik für die Fertigung: Grundlagen, Perspektiven und Beispiele für den innovativen Ingenieur. Springer Verlag, Heidelberg 2005

[2] Roesner, A.: Zweistufiges, laserbasiertes Fügeverfahren zur Herstellung von Kunststoff-Metall-Hybridbauteilen. Dissertation, RWTH Aachen, Aachen 2014

[3] Engelmann, C.; Mamuschkin, V.; Olowinsky, A.; Aden, M.: Experimental and Simulative Investigations of Laser Assisted Plastic-Metal-Joints considering Different Load Directions. Physics Procedia Volume 83 (2016), pp. 1118–1129

[4] Schricker, K.; Stambke, M.; Bergmann, J. P.; Bräutgam, K.: Macroscopic Surface Structures for Polymer-Metal Hybrid Joints manufactured by Laser Based Thermal Joining. Physics Procedia 56 (2014), pp. 782–790

[5] DIN EN ISO 8362–6: Injektionsbehältnisse und Zubehör – Teil 6: Bördelkappen aus Aluminium-Kunststoffkombinationen für Injektionsflaschen. Beuth, Berlin 2011

[6] Engelmann, C.; Hopmann, C.; Wurzbacher, S.: Laserstrahlmikrostrukturierung von Magnesiumblechen aus ME20 – Potenziale für die In-Mould-Assembly von Kunststoff/Magnesium-Hybridverbindungen. Joining Plastics – Fügen von Kunststoffen 13 (2019), pp. 182–189

Fraunhofer-Institut für Lasertechnik ILT  

https://www.ilt.fraunhofer.de

Ausgabenartikel

A crimp cap for injection vials is manufactured in a two-step process.

Fig. 1. Process for the production of mechanically interlocking plastic/aluminum crimp caps: cutting out and structuring of the thin metal sheet, insertion into the mold, forming, backmolding.

Fig. 2. Optimization of the structure geometry for thin aluminum sheet: through the scanning velocity and the number of passages, the geometry of the structure is adjusted.

Fig. 3. Mold concept for the combined deep-drawing and backmolding process.

Fig. 4. Testing the bond strength in a vertical draw-off test (left). Result (right): the vertical draw-off force of the plastic component depends on the structural configuration.

Table 1. Project participants and their fields of research.

Name - Hauptartikel

Moritz Mascher, M.Sc., research assistant at the Institute for Plastics Processing (IKV) in Industry and Craft at RWTH Aachen University, Germany; <a href="mailto:moritz.mascher@ikv.rwth-aachen.de">moritz.mascher@ikv.rwth-aachen.de</a>

Dipl.-Wirt. Ing. Christoph Engelmann is a scientific assistant at the Fraunhofer Institute for Laser Technology (ILT), Aachen; <a href="mailto:christoph.engelmann@ilt.fraunhofer.de">christoph.engelmann@ilt.fraunhofer.de</a>

Stefan Behrens, M.Sc., is also a scientific assistant at the Fraunhofer ILT; <a href="mailto:stefan.behrens@ilt.fraunhofer.de">stefan.behrens@ilt.fraunhofer.de</a>

Univ.-Prof. Dr.-Ing. Christian Hopmann holds the chair for Plastics Processing at RWTH Aachen University and is head of IKV.

The project that serves as a basis for this report was financed with funds from the Federal Ministry for Education and Research under funding number 03XP0291.