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.

Injection Molding Trends at K 2019

Spritzgießen

Kunststoffverarbeitung: Verfahren

Schaumspritzgießen

Smart Factory

Energieeffizienz

Mikrospritzgießen

Mehrkomponenten-Spritzgießen

Spritzgießmaschinen, allgemein

Kunststoffverarbeitung: Maschinen und Komponenten

Spritzgießmaschinen

Spritzgießwerkzeuge

Werkzeuge für die Kunststoffverarbeitung

Fließpressen

Handling, Handhabungstechnik für die spanende Fertigung

Automatisierungstechnik

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

A year to forget is nearing its completion. To brighten up this dreary fall season without a major event like Fakuma, injection molding machine builders have concocted various strategies.

Injection Molding Machine Builders Are Discovering New Ways to Reach Their Customers

Vernetzung / Cloudlösung für die Kunststoffverarbeitung

Biokunststoffe

Kunststoff Werkstoffe

Nachhaltigkeit

Umweltmanagement

Schneidmühlen

Kunststoff-Aufbereitung

Silikonkautschuk

Kautschuk / Elastomere

What Can You Do at Fall Fairtime,  When There Aren’t Any?

Car windows can be framed more economically and more securely with a novel thermoplastic elastomer based on styrene block copolymers (TPS), as opposed to rubber seals. Advantageously, the typically low viscosity of TPS leads to reduced glass breakage and allows thinner glass to be used. 

Novel Thermoplastic Elastomer with Good Flow Behavior and High Surface Finish 

Messgeräte für Viskosität

Oberflächenveredelung

Flexible Auto-Glass Framing 

Engel Austria GmbH, Schwertberg, Austria has developed a new injection moulding machine for the processing of all common rubber compounds and other elastomer materials. The new Engel flexseal 300 T horizontal machine with a clamping force of 3,000 kN has been designed specifically for the needs of international O-ring and flat gasket manufacturers and sets new standards for the industry with its features. 

Injection Molding Machine for O-Rings and Flat Gaskets 

Flexseal 300 T 

At the Deutsche Kautschuk-Tagung DKT 2015 in Nuremberg, Germany from June 29th to July 2nd, Arburg GmbH + Co KG, Lossburg, Germany, presented a compact manufacturing cell for removal suction cups with a threaded brass insert. The system is centered around a vertical injection molding machine (type: Allrounder 275 V) fitted with an elastomer processing package. 

Insert Molding with EPDM 

Inserttechnik

Automated Elastomer Processing 

The lighting industry is going through a technological change – from light bulb via energy saving lamp to the light emitting diode (LED). Especially for high-power LED the limit of the optical materials is reached, which affects the durability significantly. Transparent liquid silicone rubber offers a promising alternative because of its good thermal properties and high UV-stability.  

LED-Lenses Made of Liquid Silicone Rubber for Light Applications in the Automobile 

Optik

Kunststoffe

Silicone in Automotive Headlights 

Industry 4.0, lightweight construction, and combined technology – that is how one could summarize the current trends and challenges that have been the subject of countless injection molding developments during the past years. In their advance releases for the K exhibition, exhibitors clearly indicate that they are continuing along these lines. 

Injection Molding between Industry 4.0, Lightweight Construction, and Combined Technologies 

Verbundwerkstoffe / Werkstoffverbunde

Spritzprägen

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

Hybridtechnik

Reinraumsysteme / -technik

Trip to a Known Destination 

Despite the proven superiority of high-tech rubber injection molding machine models, robust lean-tech alternatives still have a large body of support, even though the available methods for increasing rubber plastication performance have already been successfully used for over ten years. This is demonstrated with a practical report at the North-German rubber and silicone processor Präzisa in Ratekau near Lübeck. 

The Rubber Injection Molding Machine Manufacturer LWB Steinl Is Staging a Sporty Comparison between Two Injection Molding Concepts 

Steuern, Regeln

Manufacturing Quality Parts Faster 

The announcements in the field of injection molding give the impression that the developments of recent years are continuing. These include the increasing digitalization of injection molding production, as well as highly integrated production cells that combine very different competencies. The spotlight shines not only on the machinery, but rather on optimum system solutions for integrating molds and individually configured peripheries in the digital and the real world. 

Fakuma 2018: Injection Molding Networked and Integrated 

Steuerungen (Hardware und Software)

ERP-Systeme

Treibmittel

Temperiertechnik

The Communicative Machine 

The Dow Chemical Company (Dow), Midland, USA, has expanded its elastomer technology platforms and capabilities, including a  range of Silastic silicone and fluorosilicone rubber technologies. For example the Silastic LTC 9400 Liquid Silicone Rubber (LSR) product line is a low-temperature-cure (LTC) LSR solution that enables short cure times at low temperatures and features processing benefits including improved rheology for fast low-pressure injection. According to the manufacturer, that creates new opportunities for part design by enabling overmolding of low-melting-point thermoplastics, actives and electrical components. These LSRs also increase robustness by reducing sensitivity to temperature gradients. 

Low-Temperature-Cure Silicone  

Silikone

Extended Elastomer Product Line from Dow 

The integration of individual parts to a multifunctional assembly is one of the important innovation potentials of plastic injection molding, e. g. the production of glass window modules for car rear doors, as practiced at Henniges Automotive. They consist of the glass pane, a web strip, and fastening clips, which are overmolded by a TPE frame to a ready-to-install assembly. For the manufacturing the automotive supplier relies on vertical C-frame injection molding machines from LWB Steinl. 

Assembly of Higher Integrated Car Window Modules through Injection Molding 

KFZ-Zulieferer

From the Vertical Machine into the  Car Door 

In cars, LEDs are taking over ever more applications and are increasingly used as differentiating design elements. In order to ensure a high luminous efficiency even with complex geometries and elongated structures, Engel has developed a new plasticizing process for manufacturing light guides.

The Principle of Starve Feeding: Injection Molding Ultrahigh Purity Light Guides

Farbmessgeräte

Messtechnik

Optische Mess- und Prüftechnik

LED / OLED-Systeme und Faseroptik

Lichttechnik

Schnecken und Plastifiziersysteme

Less Granules  Stock Means More Quality

Certain optical textiles can create a three-dimensional light effect from an LED light source. The textiles are used in interior design and in booth construction and are stretched freely on frames for this purpose. In order to protect the fabric from external influences, it should be back-molded with plastic. Thus a process that do not influence the textile structure must be developed.

Yarn-Friendly Injection Molding Process for Back Molding of Optical Textiles

Gewebe, technisch

Halbzeuge und Zwischenprodukte

Kunststoff-Halbzeuge

New Illumination of Plastics

Optics play an increasingly important role in plastic components. Glossy and even surfaces are decisive for an attractive appearance. With glass fiber-reinforced polyamides (PA), these requirements can usually only be achieved with an additional coating. A PA specially developed for surface design offers an alternative approach.

Aliphatic High-Performance Polyamide for Plastic Surfaces

Polyamide

Thermoplaste

Oberflächentechnik

Kunststoff

Bauwesen

Baustoffe

Faserverbundwerkstoffe

Andere Werkstoffe

Kunststofffasern

Verstärkungsstoffe

Glossy Components without Painting

The particle foam crowd cannot complain about a lack of interest by potential users. At least as far as demand for products with high-quality functional and optical surfaces is concerned.

A Glossy Surface Quality for Particle Foam Components

Beschichten von Kunststoffen

Chemisches Bearbeiten (Auftragen)

Partikelschäumen

Schäumen / Reaktive Verarbeitung

Lacke für Kunststoff-Oberflächenveredelung

Polyurethan

Foam Beads in Gliding Flight

Surface Modification of LSR Components Hinders Adhesion of Dirt

LSR optics offers a wide range of applications due to the optical brilliance, the possibility to produce undercut shapes not to mention the competitive pricing. The adhesive surface which is almost impossible to clean however makes the LSR parts vulnerable against contaminations. This characteristic however limits the possible application fields. To overcome this limitation Wilhelm Weber has partnered with Fraunhofer IFAM in a recent research project.

The numerous advantages explain the large potential of LSR (Liquid Silicone Rubber) for optical applications. Next to the optical quality the high flexibility and the adjustable specifications must be named. In addition, the material is chemically stable, not sensitive against light exposure or natural UV radiation and usable in a temperature range between –60 °C and +250 °C. By overmolding of LED circuit boards it is also possible to seal the electric components and implement the optical lenses in one single step.

However, the sensitive, sticky surface which can hardly be cleaned after a contamination is a big drawback. Therefore a special treatment during production is required to ensure a stable process and to avoid rejects. This allows new applications for LSR-parts and components in a non-sealed environment.

To overcome these limitations the company Wilhelm Weber GmbH & Co. KG together with the Fraunhofer Institute for Manufacturing Technology and Advanced Materials (IFAM) have started a state-supported ZIM project (“Central Innovation Programme for small and medium-sized enterprises“). Aim: develop and implement a chemical-free surface modification (registered under the OpSiLight trademark). For almost 15 years Wilhelm Weber is pioneering in the field of optical LSR applications. Remarkable, recent products are the complex LSR-Optics which are used in recent Matrix LED headlights.

During the research project which is scheduled till September 30th 2021 the overall principle of the process as well as latest results for a potential change in the refraction angle, reflection coefficient and the effect of micro cracks are examined. Furthermore investigation of geometrical effects of the UV treatment like warpage, the long-term behavior of the treated components as well as the influence of a tempering process onto the process are performed. The potentials and limitations both in term of part shapes and process parameters are discussed and representative sample are presented.

Surface Modification to Allow New  LSR Applications

For standard LSR parts, it is know that such a surface modification can be achieved by high-energetic UV-photons. However, for optical LSR parts the influence of the treatment on optical and geometrical characteristics is unknown. What is the effect of the UV exposure? To achieve the effect, the surface is irradiated with 200 nm max. typically 185 nm (Fig. 1) or 172 nm. The photons have enough energy to crack bonds in the silicon molecules in the surface layer.

As samples for the modification small optical LSR disks with 32 mm diameter were used. To evaluate the influence onto the surface quality both parts from a tool with eroded surface (VDI 24, 1.60 µm Ra) as well as one with a high-polished surface were produced and evaluated. Due to the good molding this results in crystal clear parts for the polished mold and slightly opaque for the first version. With a XPS analysis (X-ray photoelectron spectroscopy) of the modified part surfaces it was demonstrated that the oxygen concentration in the molecule structure is more than doubled, while the carbon concentration was reduced up to a factor of 10. Therefore it was proven that the majority of molecules in the surface layer were modified.

By binding oxygen radicals from the surrounding atmosphere onto the silicon molecule fragments a glass-like surface is created. The thickness of the layer in the micrometer range can be modified by the dose and the wavelength of the radiation applied. The whole process can both be performed in normal or an oxygen-reduced atmosphere, additional chemicals are not required. However it must be ensured, that the whole surface which should be modified can be reached by the radiation, as the process is radiation induced. As the process window is pretty large also complex shapes and even areas which are slightly shaded are possible.

First experiments have demonstrated, that dust by normed test dust samples of polyamide fibers can be easily blown away by compressed air from the treated samples, while the untreated samples can be cleaned. In addition detailed measurements on transmission and reflection did not show any differences between the treated and the untreated material. However, small micro cracks on the surface may appear which might be reasons for property changes. By a suitable selection of the process parameters these micro cracks can be minimized or even avoided.

To evaluate the process the treatment of the 3 mm thick LSR disk (grade: Silastic MS-1002; manufacturer: Dow Chemical) both the radiation time as well as the surface is varied. Plotting the spectral transmission (Fig. 2) demonstrates, that below 450 nm the transmission is not affected at all, while below 450 nm the transmission is slightly reduced, which however is not relevant is almost all applications.

First Successful Application on  LED Circuit Board

The advantages of the surface treatment with high-energetic VUV radiation (vacuum-ulta-violation) were shown in some test series. As an example application a LED circuit board with 98 LEDS (Title figure) which is overmolded by an optics with a combined sealing (Fig. 3) was covered by 50 % and irradiated with UV. After this treatment norm dust – in this case consisting of polyamide fibers of 0.3 mm length – was applied onto the surface. Afterwards the part was shaken and the fibers were blown away with compressed air. While the dusts stick to untreated surface and could not be removed, the treated surface was dust free. (Fig. 4). The amount of dust just falling of the board also shows how much dust actually sticks to the surface. In addition, the surface also has an improved surface feel.

In addition optical parameters like the mean intensity, the standard deviation and also a possible color shift were evaluated. It could be shown, that the intensity of the treated area (32.8 x 2.9 AE) and the untreated area (31.9 x 2.0 AE) were the same. Also the recorded intensity patterns and the direct pictures of the boards did not show any difference in light distribution, angle of radiation or spectral distribution.

Additional Advantages of the  VUV Treatment

The newly created “glass-like” surface of the LSR is less sensitive to dust as demonstrated. In addition overmolding or gluing is possible in further process steps. Additional benefits oft he VUV treatment are:

<ul><li> Long-term test cycles (> 18 months) show, that the modification is long-term stable.</li><li> The modification is resistant against climate change, heating, storage in water, chemicals, etc.</li><li>Gluing onto the substrate with typical methods like epoxide resin, polyurethane resins or tapes is possible, overall the surface energy is enhanced significantly.</li><li>Adhesive free bonding onto glass is possible with freshly treated LSR.</li><li> The glass-like surface has a conformable “silk-touch” feeling.</li><li>The treated surface offers a high bio-compatibility.</li></ul>

The surface modification also results in an enhancement of the surface hardness. The nano hardness and the elastic modulus was measurement with a nanoindenter. The hardness was measured as a function of the penetration of the measuring tip. The measurements shows, that the hardness and stiffness of the layers close to the surface are significantly enhanced. At a contact depth > 20 mm the value is enhanced by a factor of more than 100 (!), which is the highest value published.

Recently, the process window is evaluated exactly. In parallel computer simulations are performed to be able to simulate the perfect process parameters and radiation distributions for specific parts. The process itself is fully ready for operation there Weber is recently looking for actual projects and applications partners which can benefit from the advantages.

UBCOM Kommunikationsmanagement UG (haftungsbeschränkt) 

www.ubcom.cc

Ausgabenartikel

Fig. 4. Details to compare the treated (left) and untreated (right) areas of the sample board after knocking off the dust

Fig. 2. Influence of the treatment to the spectral transmission, measured trough a 3 mm thick LSR disk. For wavelength > 450 nm no effect could be measured, while below 450 nm there is a slight decrease in transmission which is however not of any effect in most applications

Fig. 3. View into the tool to produce the test boards for the modification 

Half of the board was treated with VUV while the other half has covered. Afterwards norm dust was applied onto the board uniformly and than knocked off (once) in upright position. The dust sticks to the untreated areas while falls of the treated areas

Fig. 1. Surface modification is performed with 185 nm low-pressure mercury lamps

Name - Hauptartikel

Dipl.-Phys. Univ. and MBA Andreas Schäfert is Director Sales and Business Development Medical Devices at Wilhelm Weber GmbH & Co. KG, Esslingen, Germany; <a href="mailto:a.schaefert@weber-esslingen.de">a.schaefert@weber-esslingen.de</a>

Wilhelm Weber GmbH & Co. KG was founded 1925 by Wilhelm Weber and Ernst Eberspächer. It is located in Esslingen am Neckar, near Stuttgart, Germany. Weber portfolio consists of three main branches: the construction of high-quality injection molding tools for multicomponent-, LSR- or high-precision applications, the production of actual injection parts as well as assembly and the production of rotary units. Weber offers the whole value chain of injection molding production, from design and customer support for parts over construction, production, assembly and verification. Webers main customers are from the medical, electrical and automotive branch, while having a lot of long-term business relations with well-known partners. The company has a quality management according to DIN EN ISO 9001:2008 and has recently about 120 employees.