We look behind the cavity walls and along the data cable at what hot runner technology now offers in terms of mechanical, electronic and digital expertise.

The smart Control monitoring unit permits integrated monitoring of the injection molding production cell, including the mold, hot runner system and all ancillary components. The “Luer connector” application case was on show at K 2022.

16:9

State-of-the-Art Injection Molding Solutions at K 2022: Hot Runner Technology

Spritzgießen

Kunststoffverarbeitung: Verfahren

Doriat, Clemens, Dr.

Mikrospritzgießen

Digitale Transformation

Wirtschaft

Innovationen und neue Technologie

Spritzgießwerkzeuge

Kunststoffverarbeitung: Maschinen und Komponenten

Werkzeuge für die Kunststoffverarbeitung

Normalien und Heißkanaltechnik

Komponenten für die Kunststoffverarbeitung

Mess-, Steuer- und Regelgeräte

Qualitätssicherung

Qualitätssicherung Kunststoff

Temperaturregler

Messtechnik

Sensoren / Messwertaufnehmer

Heißkanalsysteme

Additive Fertigung

Everything under Control

Witosa is replacing titanium with 3D-printed steel elements in its hot runner systems. Its long-term goal is carbon neutrality.

Reducing the CCF through Titanium-Free Mold Constructions

Hot Runner, Carbon Neutral

Jessica Poliner has been appointed President of Barnes Molding Solutions. She replaces Norbert Scheid, who retired from Barnes Group in December 2020.

Jessica Poliner has been appointed President of Barnes Molding Solutions

Werkzeug- und Formenbau

Dienstleistungen

Werkzeug-, Formen- und Modellbau

New Management to Head Barnes Molding Solutions

At K 2022, Engel, with its partners Alpla Group, Brink and IPB Printing, is presenting a quantum leap for the packaging industry. Thin-wall containers can for the first time be produced from PET directly by injection molding in only one process step.

Fig. 1. The thin-walled containers are injection molded from rPET.

Messe K-Kunststoffmesse

kunststoffe-international.com

kunststoffe.de

Schmelzefilter

Kunststoff-Aufbereitung

Polyethylenterephthalat

Kunststoff Werkstoffe

Thermoplaste

Energieeffizienz

Industrie 4.0 für die Kunststoffverarbeitung

Industrie 4.0

Spritzgießmaschinen

Kunststoff-Rezyklat

Kreislaufwirtschaft

Processing rPET by Thin-Wall  Injection Molding

This year, the world’s leading trade show K has succeeded in presenting practical solutions for greater resource efficiency on a broad front. A first foray through the trade show grounds.

K 2022 gave numerous practical examples showing visitors how recyclates can be reliably processed with digital aids.

State-of-the-Art Injection Molding Solutions for Greater Resource Efficiency.

State-of-the-Art Injection Molding Solutions at K 2022

Solar / PV

Energieerzeugung

Erneuerbare Energie

Schaumspritzgießen

Temperiertechnik

Mehrkomponenten-Spritzgießen

Condition Monitoring / Prozessüberwachung

Instandhaltung

Biokunststoffe

Handling, Handhabungstechnik

Automatisierungstechnik

Elastomer-Spritzgießen

Oberflächentechnik

Digitalisierung

Silikonkautschuk

Kautschuk / Elastomere

Compoundieren

It Can Be Done!

Moldmaster uses thermoanalysis to identify melt leakage in the manifold outlet.

The TempMaster control unit detects leakages in the manifold recess by thermoanalysis.

Heißkanaltechnik

Messung von Umgebung (Klima)

Leak Detection in Manifolds

Injection molding: Family molds can produce a wide variety of parts in a single shot. Where the challenges lie in process control.

Three at once: a six-axis robot removes the final injection-molded assembly, consisting of door trim, map pocket and sill.

One Tool, One Shot, Three Parts

A group of Italian companies has developed three automated injection molding lines for the production of single-use compostable cutlery.

Armido Marana (left) and Antonio Munarini of Ecozema in front of the Engel e-mac 280 for the production of single-use cutlery in compostable bioplastics.

Discovery Tour

Länderspecial Italien

Nachhaltigkeit

Umweltmanagement

Compostable Bioplastics:  Italy Sets the Standard

According to the company, the UltraShot Injection System provides part design freedom, while improving part quality and speed of mold qualification.

The UltraShot Injection System filled the entire part where a conventional injection molding process at 2758 bar could not

Husky introduces the UltraShot Injection System

Kunststoffverarbeitung allgemein

Kunststoffverarbeitung

Spritzgießmaschinen, allgemein

Kunststoffverarbeitungsmaschinen

Next Generation Melt Delivery and Control System

The completion of the transaction is subject to customary regulatory approvals and is expected by the second quarter of 2021.

Oerlikon acquires Italian company INglass S.p.A. and its market-leading HRSflow business unit for hot runner system technologies

Oerlikon Signs Agreement to Purchase INglass

For the further development of the Streamrunner and also for customer demonstration purposes, Hasco hot runner has developed an innovative 32 cavity injection mold tool.

The special feature of the mold is the 32-cavity Hasco Streamrunner

New Design Possibilities in Moldmaking

Products intended for use in building services must meet very high quality requirements in terms of both their constituent materials and functionality. A single-cavity mold for a floor grate made by Barku, which appears to be a simple part at first glance, called for a certain level of technical sophistication. This was provided by a moldmaker with the necessary technical understanding and hot-runner manufacturer Witosa who, between them, devised the right solution for what proved nevertheless to be a complex mold.

Sebastian Lotzin, CEO of Barku’s U. S. subsidiary, with floor grate (3250 g) in the 10,000-kN injection molding machine that makes the part

Sequential Injection with a 6-Fold Valve Gate System for a Floor Grate

A Simple Cascade

With the Streamrunner from Hasco, the first additively manufactured hot runner, now completely new and space-saving options are also available for valve gate systems.

Fully balanced 20-cavity system with valve gate technology with an outer dimension of the 3D-printed manifold of just 124 x 124 mm. 

Additively Manufactured Hot Runner Manifolds with Needle Valve

Nowhere are the demands imposed on materials higher than in the area of medical technology. That is understandable because, after all, what is ultimately at stake here is the patient’s health. But any materials manufacturers seeking to use hot runner technology to process polymers in compliance with strict directives and differentiated legal regulations also need the expertise possessed by the hot runner manufacturer’s application engineers.

Günther has recently installed two new injection-molding machines for customer trials in its technical center.

Testing the Processing Limits of Modified POM Copolymer

Polyoxymethylen

Medizintechnik

Looking over the Application  Engineer’s Shoulder

For the production of a container for a disinfectant gel precision mold maker Matrix developed a complex 6+6+6-fold 3-component mold. Two single parts are manufactured in one step and sealed in the tool by overmolding with a third component. The demanding mold design which uses two rotating index plates required a tailored hot runner solution which was supplied by Ewikon. 

Tailored Hot Runner Solution for a Demanding 3-Component Mold Concept 

Molded and Assembled in One Work Cycle 

Flexible Injection Solutions  with Adapter Plates

Economical Solution for the Production of Thermoplastic Large-Structure Components

For the transformation of industrial production into an economic system with waste-free, low-CO2 manufacturing processes, injection-molded, highly stressable thermoplastic large components are also required.  Production systems for these molded parts can be flexibly and economically reconfigured or expanded using hot runner adapter plates.

Production systems for large molded parts can be flexibly and economically reconfigured or expanded using hot runner adapter plates.

In order to meet demands for a reduction in the carbon footprint of vehicles and aerospace, there is no way around thermoplastics. Injection molding has proven to be an effective and economical process for the production of heavy-duty lightweight components for these product groups. This process is depending on high quantities as well as high machine- and/or plant costs. The requirements and functions of a molded part determine its geometry, which in turn determines the size and design of the tool, machine- and installation engineering. If special requirements are placed on the thermal, mechanical or other properties of the molded parts, combinations of different thermoplastics, the incorporation of glass or carbon fibers and/or the overmolding or injection of organic sheets as well as LFT tapes (long fiber-reinforced thermoplastics) are state of the art.

In order to meet today’s market requirements for productivity, production plants must be adapted quickly and flexibly to newly manufactured molded parts. Hot runner adapter plates increase flexibility and productivity in the injection molding production of large thermoplastic lightweight molded parts. In contrast to definitions of the size of general industrial products according to Behrens [1], injection-molded parts can already be described as “large” from dimensions over 1000 mm.

The Area of Conflict between Productivity and Flexibility

The sizing (configuration) of an injection molding machine is always under pressure between productivity and flexibility. More generally, high productivity can only be achieved with less flexibility, which is colloquially referred to as the “contradiction of manufacturing technology” [2, 3]. Highly productive injection molding machines with low flexibility are or have been machines for the production of CD blanks with extremely short cycle times. The drives of the individual machine axes are designed for this specific product and then have the lowest energy consumption at this operating point. Multipurpose machines, on the other hand, have an operating range – their drives operate predominantly in the partial load range with lower efficiency.

Since operating times of between 20 and 30 years are expected, especially for large injection molding machines, the equipment features once taken during the design/condition are difficult to change again and at great cost. On the other hand, it is difficult to produce “reconfigurable” injection molding machines, as described for machine molds [2, 4]. A flexible adaptation and expansion of the technical possibilities to new production tasks is possible by additional assemblies on the individual machine or plant components if the configuration of the fixed and moving plate is retained and the tool is changed. The control of the individual plant components for the combination of different production technologies is a complex matter [5]. For such complex production lines hot runner intermediate plates can be a cost-effective alternative compare to new machines or to machine and molds.

The main criteria for the design of the injection molding machines in relation to the geometry of the molded part to be manufactured are shot volume, injection pressure and closing or locking forces. Large-volume molded parts require high injection volumes at relatively low injection pressures and have long cooling times. Large-area molded parts have long flow paths with thin wall thicknesses and thus require high injection pressures. Thus, the flow properties of the polymer melts and the geometric dimensions become the limiting criterion for the molded part size. This geometric-rheological boundary can be partially circumvented with cascade injection molding.

Hot runners in injection molds are state of the art and well described in their functions [6, 7]. The hot runners for the adapter plates, as offered by A&E Produktionstechnik GmbH, are rheologically designed and dimensioned. They are installed movably in the adapter plates. Reasons for this are:

<ul><li> The clamping of different molds, each with different layers of the sprue bushes, is easier than with a fixed installation, because a time-consuming dimensional coordination between the layers of the hot runner nozzle and the mold sprue bush is no longer necessary.</li><li>The connection of the hot runner nozzle to the mold sprue bush is not visible to the machine operator. This masked connection is reliably designed to be leak-free.</li></ul>

The hot runner is pivoted in a manually adjustable frame in the steel plate. By adjusting the frame, a nozzle stroke is possible – depending on the size of the adapter plate and customer requirements between 5 and 30 mm.

Sprue bushes and nozzles are designed with radii. Compared to other designs, such as flat surfaces or immersion nozzles, the radius design allows a greater tolerance for a possible offset of the melt channel of the mold to the hot runner. Since no melt may escape at the connection point between the hot runner nozzle and the mold sprue bushing even under the effect of 2000 bar injection pressure, the hot runner adapter plates have integrated assemblies for applying the nozzle contact force. This force thus acts independently of the nozzle contact force of the injection unit of the machine. Depending on customer requirements and the available installation space, the nozzle system force can be built up in the steel plate via spring packages or by hydraulic or pneumatic cylinders. The nozzle stroke and contact force of the hot runner nozzle are manually adjusted via an adjustment device on one side of the hot runner adapter plate (Fig. 1).

In order to reliably prevent melt leaks at the non-visible connection between the hot runner nozzle and the mold sprue bushing, this point is monitored by a capillary with a small stream of compressed air. Escaping melt leads to an increase in pressure of the compressed air flow (Fig. 2). A sensor converts this pressure increase into a signal for the machine control. Experience in the field has shown that the masked connection without this monitoring is a source for overmolding for some hot runners.

Reduced Carbon Footprint  by Using Recyclate

If the installation space in the steel plate allows it and customers required it necessary, sensors can be installed in the hot runner adapter plates that record the melt parameters: temperature, pressure, pressure difference and, if necessary, other process variables. In addition, the hot runner adapter plates can be offered with shut-off nozzle as well as shot-off sprue bushings. Optimized melt-flow channels are just commonly.

 Current demands to reduce the CO2-footprint for plastic molded parts are already leading to an increased use of recyclate (regrind, granulate). In order to continue to meet this requirement, the sandwich process (co-injection) is ideal for using the recycled material as a core material. This process can be carried out easily and cost-effectively with hot runner adapter plates on commercially available 2-component injection molding machines (due to the function-related shut-off of the nozzle when “filling”/dosing the injection cylinder).

Various types of “sandwich nozzles” are offered on the market in different process variants. These variants are all based on the technical implementation of the source flow effect and laminar flow. They are characterized in everyday production by more or less large advantages and disadvantages, for example by a simpler machine design but also by a less flexible process sequence (no sealing or rinsing phase) and partial occurrence of melt leaks in the nozzle chamber (due to the function-related shut-off of the nozzle when “filling”/dosing the injection cylinder) [8, 9].

Shut-off nozzle and shut-off sprue bush which are installed in the hot runner enable high process stability – comparable to well-known machine shut-off nozzles that are mounted directly on the plasticizing and injection units. In processes with the machine nozzle moving away, for example in injection molding systems with sliding table, the sprue bush shut-off prevents the melt from leaking out of the hot runner. For other special injection molding processes, such as foaming or processing of long-fiber material, the hot runners can be modified accordingly.

At Chemnitz University of Technology, Germany, an injection molding machine of the type KM 2300 MXW Twin SP24500/810 with bolt-on unit SP3000 (manufacturer: Krauss Maffei Technologies GmbH, Munich, Germany) is used as part of the Federal Excellence Cluster Merge. For them, a hot runner adapter plate measuring 2850 x 1580 x 196 mm was built with two exchangeable hot runners, each with shut-off nozzle and sprue bush shut-off. A hot runner directs the melt from the bolt-on unit to the center of the plate.

A second hot runner leads the melts from the bolt-on unit and from one of the two centrally arranged injection units simultaneously and/or sequentially to the nozzle in the center of the plate. The hot runner adapter plate can be attached to all four mold mounting platens of the machine (Figs. 3 and 4).

For an injection molding machine of the type Engel duo 2700 (manufacturer: Engel Austria GmbH, Schwertberg, Austria) with two parallel horizontally arranged injection units, a hot runner adapter plate of size 2180 x 1750 x 120 mm was built, which combines the melt flows of both injection units on a centrally arranged nozzle. This made it possible to increase the injection volume.

The tool is fastened with an electromagnetic quick-release plate (Figs. 5 and 6). This configuration shows production of interior parts for the automotive industry. Further examples of the use of hot runner adapter plates are described in literature [9–11] and on the authors’ websites.

Hot runner adapter plates are supplementary assemblies to increase the flexibility and productivity of injection molding machines. Experience gained so far from many years of production of these plates confirms the described advantages of this technology. We are continuously working on the further development and development of new areas of application. In the technical center of Chemnitz University of Technology, there are opportunities for interested parties to test these intermediate plates in combination with the company’s own molds.

[1] Behrens, B. A.; Nyhuis, P.; Overmeyer, L.: Divergent structure sizes in industrial production, et al. Towards a definition of large scale products. Prod. Eng. Res. Devel 8 (2014), pp. 153–164; URL: <a href="https://doi.org/10.1007/s11740" target="_blank">https://doi.org/10.1007/s11740</a>–013–0503–1

[2] Franz, H.: Die Balance zwischen Produktivität und Flexibilität. Kunststoffe 107 (2017) 5, pp. 30–31

[3] Lorenzer, T.: Wandelbarkeit in der Serienfertigung durch rekonfigurierbare Werkzeugmaschinen. Fortschrittsberichte VDI-Reihe 16 (2011), Nr. 199

[4] Stehle, T.; Heisel, U.: Konfiguration und Rekonfiguration von Produktionssystemen. In: Spath, D. et al. (Hrsg.): Neue Entwicklungen in der Unternehmensorganisation. Springer-Verlag ; URL: <a href="https://doi.org/10.1007/978" target="_blank">https://doi.org/10.1007/978</a>–3–662–55426–5_39

[5] N.N.: Modulare Produktionsanlagen für Hybridbauteile. MoPaHyb_Abschlussbericht, KIT Karlsruher Institut für Technologien, 07–<a href="http://2019.pdf" target="_blank">2019.pdf</a> (<a href="http://kit.edu" target="_blank">kit.edu</a>) <a href="https://www.ict.fraunhofer.de/content/dam/ict/de/documents/projekte/MoPaHyb_Abschlussbericht.pdf" target="_blank">https://www.ict.fraunhofer.de/content/dam/ict/de/documents/projekte/MoPaHyb_Abschlussbericht.pdf</a>

[6] Beaumont, J. P.: Auslegung von Anguss und Angusskanal. Carl Hanser Verlag, München 2013

[7] Johannaber, F.: Handbuch Spritzgießen. Carl Hanser Verlag, München 2002

[8] Internet-Seiten der Ferromatik Milacron GmbH: <a href="https://www.milacron.com/de/?s=Monosandwich" target="_blank">https://www.milacron.com/de/?s=Monosandwich</a>, abgerufen am 15.06.2022

[9] Skinmelt – Internetseiten der Engel Austria GmbH: <a href="https://www.engelglobal.com/de" target="_blank">https://www.engelglobal.com/de</a>, abgerufen am 15.06.2022

[10] N.N.: Engel stärkt Leichtbaukompetenz. K-Zeitung 68. Jahrgang (2017) 20, p. 7

[11] Nendel, W.; Reichert, V.: Flexible Technology Module. Kunststoffe international 106 (2016) 8, pp. 56–58

[12] Zinckgraf, S.: Spritzgiess-Systemlösung als Kombination Spritzen und Pressen. Plastverarbeiter, 66. Jahrgang (2015) 2, pp. 36–38

Ausgabenartikel

Fig. 2. Compressed air flow capillary on a  hot runner nozzle for detecting melt leakage.

Fig. 3. Installation version of the hot runner intermediate plate on the fixed plate of the KM 2300 MXW Twin SP24500/810 injection molding machine with bolt-on unit SP3000.

Fig. 4. Installation situation of the hot runner adapter plate on the middle plate of the KM 2300 MXW Twin SP24500/810 machine with bolt-on unit SP3000.

Fig. 5. Installation situation in the mold room of the Engel duo 2700: magnetic mold clamping plate in front of hot runner adapter plate.

Fig. 6. Graphical representation of the arrangement of (from left to right) magnetic clamping plate, hot runner adapter plate and fixed mold mounting plate in the Engel duo 2700.

Melt transfer from two on the side injection units of an Engel v-duo 2300 RTM into the middle of the hot runner intermediate plate mounted on the sliding table. 

Fig. 1. Adjustment device for nozzle stroke and nozzle system force with nozzle position indicator.

Name - Hauptartikel

Dipl.-Ing. Adam Czech is a research associate at the Chair of Lightweight Structures and Plastics Processing (SLK) at Chemnitz University of Technology, Germany; <a href="mailto:adam.czech@mb.tu-chemnitz.de">adam.czech@mb.tu-chemnitz.de</a>

Prof. Dr. Wolfgang Nendel is deputy head of the Chair of Lightweight Structures and Plastics Processing (SLK) at Chemnitz University of Technology; <a href="mailto:wolfgang.nendel@mb.tu-chemnitz.de">wolfgang.nendel@mb.tu-chemnitz.de</a>

Dr. Volker Reichert is Managing Director of A&E Produktionstechnik GmbH, Dresden, Germany; <a href="mailto:info@a-e-produktionstechnik.de">info@a-e-produktionstechnik.de</a>