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

The required screw diameter can be ascertained on the basis of the shot volume. The formula for the average residence time can be used to estimate the degree of utilization and the thermal load on the material.

Part 1 of the Series Discusses the Basic Design of a Plasticizing Unit and the Correct Choice of Injection Unit

Schnecken und Plastifiziersysteme

All about Plasticizing Screws

To be able to carry out the practical test in a resource-saving manner, the designers use simulation tools to assess the screw geometry. What is important here is explained using a 3-zone screw as an example.

Part 2 of the Series Deals with Basic Methods for Evaluating a Screw Geometry

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

Less Granules  Stock Means More Quality

ARBURG is one of the world‘s leading manufacturers of plastic processing machines. The product portfolio encompasses ALLROUNDER injection moulding machines with clamping forces of between 125 and 6,500 kN, the freeformer for industrial additive manufacturing, plus robotic systems, customer and industry-specific turnkey solutions, and further peripheral equipment.

ARBURG GmbH + Co KG  

https://www.arburg.com

Abkantmaschinen, -pressen, -bänke

Blechbearbeitungsmaschinen

Maschinen für die spanlose Fertigung

Additive Fertigung

Anlagen für die Additive Fertigung

Antriebselemente

Lineartechnik

Maschinenelemente

Ceramic-Injection-Moulding, CIM

Condition Monitoring für die Qualitätssicherung

Industrie 4.0 für die Qualitätssicherung

Kennzahlen

Qualitätsmanagement

Kennzahlen, Q-Leitstand, Q-Monitor

Qualitätssicherung

Kühlelemente, aktive

Kühlkörper

Elektromechanik

Management-Informationssysteme

Medizintechnik

Mehrfarben-Spritzgießmaschinen

Mikrobauteile

Montage

Mischer

Kunststoff-Aufbereitung

NE-Metalle

Metall Werkstoffe

Partikelschäumen

Schäumen / Reaktive Verarbeitung

Produktionssystem

PUR-Schäummaschinen

Rapid Manufacturing

Rapid Prototyping

Reinraumsysteme / -technik

Reinraumtechnik

Betriebsausrüstung / Betriebsmittel

Reporting-Tools

Rückverfolgbarkeit, Traceability

Schnecken und Zylinder

Spanneinrichtungen

Systemperipherie

Spritzgieß-Zubehör und Einzelteile

Stetigförderer

Fördertechnik

Logistik

Trockner

Vorbeugende Instandhaltung für die spanende Fertigung

Industrie 4.0 für die spanende Fertigung

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

Silikonkautschuk

Kautschuk / Elastomere

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

Infrared heating technology has become established as the standard in the processing of thermoplastic composite materials. The focus is on process control. On the one hand, it is important that the heating process is fast, on the other hand, the material must not be overheated. It is also important to achieve excellent temperature homogeneity. Simultaneous processing of blanks with different thicknesses is a particular challenge.

Efficient and Precise Heating up of Thermoplastic Composites

Steuern, Regeln

Infrarotstrahler

Verbundwerkstoffe / Werkstoffverbunde

Organobleche (gewebeverstärkte Thermoplast-Halbzeuge)

Halbzeuge und Zwischenprodukte

Kunststoff-Halbzeuge

Software-Based Control of IR Ovens

The new injection-molding machine Engel duo speed combines productivity and efficiency with short cycle times in a high clamping force range. The two-platen machine is thus making inroads into a range of packaging applications that were formerly the domain of toggle machines.

Engel Duo Speed Expands the Machine Portfolio for Packaging Applications

High-Speed Machine with a  Small Footprint

The fifth broadcast by arburgXvision was all about the exciting question of how productivity can be optimized by bringing together technology, organization and digitalization in the ideal manner.

5. arburgXvision: „Savings through Hidden Benefits!“

The Wilhelm Böllhoff GmbH & Co. KG employs Arburg’s ALS host computer system as a uniform MES at locations all over the world. Not only all their injection molding machines are networked with information technology via ALS, but hundreds of machines and turnkey systems for metalworking and assembly, as well. Some 3000 injection molds are also managed. This generates transparency in everything from order planning and process optimization to maintenance.

Böllhoff Uses ALS as a Uniform Global MES for Injection Molding and Metalworking

Big Data für die Qualitätssicherung

Qualitätssicherung Kunststoff

Energiemanagement

Completely Joined to the Host Computer System

The toolmaker Siebenwurst uses injection molding simulation to optimize part design and production processes in its routine workflows. Among other things, Simcon’s software ensures the quality and dimensional accuracy of the plastic frame for the first series-produced injection molded e-bike.

Controlling Complex Development and Manufacturing Processes, Using Simulation

Composite-Halbzeuge

Dienstleistungen

Werkzeug-, Formen- und Modellbau

A Bike Frame from an Injection  Molding Machine

At the 2019 K fair, Arburg and Simcon showcased a filling process proceeding in real-time, as a 3D animation, on the display of a machine control panel, for an example of sunglasses, made of PA12. All that was needed to prepare this, was to load the simulation model, as well as the geometry of the part, directly onto the machine controls. This sounds almost too easy to be true. Right?

Interview with Eberhard Duffner and Paul F. Filz by the Magazine Kunststoffe

Doriat, Clemens, Dr.

Interview

SIGMA Engineering GmbH is a 100% daughter company of the technology and market leader in casting simulation located in Aachen, Germany, (<span class="webadresse">www.magmasoft.de</span>). Owner managed and fascinated by technology we make modern polymer forming processes transparent. With our simulation product SIGMASOFT® our customers optimize plastics parts and injection molds as well as production conditions of thermoplastic-, elastomer-, thermoset- or MIM/CIM applications.

SIGMA Engineering GmbH  

https://www.sigmasoft.de

Auswerte- und Analysesoftware

Beratung und Consulting

Kunststoffverarbeitung

Lohnfertigung

Logistik Software

Logistiksysteme Software

Produkt- / Formteildesign

Produktentwicklung(sprozess)

Prozesssimulation

Prozessvisualisierung

Rheologie

Werkstoffprüfung

Making the production of optical lenses economical while maintaining a certain level of product quality poses a huge challenge. Aside from the need to modify the geometry of the molded part, there is often a debate about the right production strategy.

Simulation as a Tool for Weighing Process Options before Producing Optical Components

Simulation Produkt- / Formteildesign

Optische Komponenten / Baugruppen

Photonik

Optik

More is Less

The switchover process from the injection phase to the holding pressure phase is frequently the cause of reduced part quality in injection molding.

Phaseless Process Control Should Revolutionize the Switchover Process

Mess- / Regel- und Prozessleittechnik

Prozessautomation

Mess-, Steuer- und Regelgeräte

The Switchover Problem and  its Consequences

Part 3 of the Series Deals with the Tests to Optimize the Screw Geometry

In the second part of the series, calculations were carried out on the throughput behaviour, pressure build-up capacity and the melting process on the basis of an exemplary geometry. These results are now to be examined in more detail and subsequently optimized. For this purpose, the effects of adjusting some selected geometry parameters have to be investigated and interpreted.

In the second part of the series, calculations were carried out on the throughput behaviour, pressure build-up capacity and the melting process on the basis of an exemplary geometry. These results are now to be examined in more detail and subsequently optimized.

The main task of a plasticizing unit is to melt the plastic granulate and homogenize the molding compound. Plasticizing units in which the heated barrel is combined with a three-zone screw are widely used. In the feed zone, the granules are fed from the hopper into the plasticizing unit. In the compression zone, the screw flight narrows so that the molding compound is compressed and melts due to the interaction between the frictional heat generated and the heated cylinder. In the metering zone, the viscous melt is mixed to distribute additives and fillers as well as heat evenly.

In part 1 and part 2 of the series (Kunststoffe international 10/2020 and 1/2021), the basic principles of plasticizing unit design and screw geometry calculation were discussed. Calculations concerning throughput behavior, pressure build-up capacity and the melting process were demonstrated on an exemplary screw geometry. In our example the average metering performance was about 12.49 g/s with a back pressure of 80 bar and a circumferential screw speed of 300 mm/s – a value which can be improved by appropriate geometry optimizations.

As shown in the second part of the series, the screw showed a considerable overcapacity for pressure build-up. With a back pressure of 80 bar, the screw was able to reach a peak pressure of just under 160 bar. But in the interest of gentle plasticizing to protect the material, this peak pressure should be reduced to below 120 bar in practice.

However, the melting process developed very positively, as the material was already completely liquefied after traveling about L/D = 8 in conveying direction. In the course of further optimization, it is now necessary to prevent solid material from traveling too far into the metering zone, since in extreme cases this could lead to excessive wear of the screw, the barrel and the check valve. Ultimately, this is also why the dwell time of the melt should not be allowed to fall below the minimum dwell time recommended by the manufacturer of the material.

Step 1 of Optimizing the Geometry: Shortening the Metering Zone

As a first step, the length of the metering zone should be reduced. The idea behind this is that the metering zone with its low flight depth and considerable length produces a corresponding blockage effect on the preceding screw zones. This is also shown by the closeness of the peak pressure point to the end of the compression zone prior to the optimization attempt. In this first test, the metering zone is shortened from 5.5 D to 3.5 D. To keep the total screw length of 22 D unchanged, the compression zone is lengthened (from 5.5 D to 7.5 D) accordingly (Table 1).

The effect on the peak pressure is negligible. However, the pressure gradient in the metering zone has now become steeper, since the pressure peak has moved closer to the check valve (Fig. 1). For the sake of completeness, it should also be mentioned that the change has a similarly minor effect on the melting process and throughput. Liquefication is now completed at L/D = 8.9, and the average metering performance is about 13.02 g/s.

Step 2 of Optimizing the Geometry: Increasing the Metering Zone Depth

Since the effect achieved by shortening the metering zone is only minor, the flight depth is now examined as a second step. The individual zones are returned to their original lengths (feed zone 50 % of the total length, metering and compression zone 25 % each). The flight depth ratio of 2 zones remains unchanged, but that of the metering zone is increased by between 25 and 30 %. In rounded figures, a flight depth of roughly 3.2 mm is calculated for the metering zone (Table 2).

After carrying out this optimization attempt, the pressure curve shows that the original pressure of 158 bar has been reduced to 129 bar (Fig. 2). It is interesting to see how a 28 % increase in the flight depth reduces the blockage effect much more strongly than a shortening of the metering zone by some 36 %.

Other points worth mentioning here are the average metering performance of 15.23 g/s reached by this move, and the shift of complete liquefication to L/D = 10.4. Moreover, it is basically possible to vary the compression ratio, the zone length ratios, etc., in a similar way in order to optimize their influence on the processing parameters.

Where these tests are carried out for many different materials and harmonized accordingly, a universally applicable screw geometry emerges as a result. At Wittmann Battenfeld GmbH, Kottingbrunn, Austria, multi-purpose screws of this kind are sold under the name of Unimelt. They stand out by their extremely wide range of possible applications in thermoplastics processing. In combination with a suitable anti-wear package, they offer a long-lasting plasticizing system. Wherever special challenges in injection molding must be mastered, the Wittmann Battenfeld team of engineers stand ready to help their customers in a joint search for the optimal plasticizing solution to fit every individual purpose.

Empirical tests and simulation-supported test series allow the design of a screw tailored to the specific application (for example, low pressure build-up or high plasticizing flow). Outside this application, however, such a screw cannot reach its full potential. It is also possible to generate a universal screw by means of comprehensive test variations, which can be used for a wide variety of materials and process parameters.

Wittmann Battenfeld GmbH  

https://www.wittmann-group.com

Ausgabenartikel

Through empirical tests and simulation-supported test series, a screw can be designed in a tailor-made manner for the respective application 

Table 1. Geometry optimization, test 1: Metering zone shortened, compression zone lengthened

Table 2. Geometry optimization, test 2: Screw with increased flight depth

Fig. 1. First test for geometry optimization: Pressure curve along the screw at stroke position 50 mm

Fig. 2. Second test for geometry optimization: Pressure curve after the increase of flight depth by approx. 28 %

Name - Hauptartikel

<b>Filipp Pühringer</b> heads the Process Engineering Development Department at Wittmann Battenfeld GmbH in Kottingbrunn, Austria.