Marbling is often a real eye-catcher in plastic components. However, the effect is difficult to create and there are some pitfalls when it comes to reproducibility. Novel nozzles for injection molding machines in combination with a special dosing technology allow marbled molded parts to be produced far more easily in a much more robust process.

A 3D-Printed Nozzle and Modified Dosing Method Deliver Reproducible Marbling  in a Robust Process

Spritzgießen

Kunststoffverarbeitung: Verfahren

Spritzgießwerkzeuge

Kunststoffverarbeitung: Maschinen und Komponenten

Werkzeuge für die Kunststoffverarbeitung

Kunststoffe

Photonik

Optik

Dienstleistungen

Werkzeug-, Formen- und Modellbau

Additive Fertigung

Farben, flüssig

Kunststoff Werkstoffe

Additive

Exciting Design instead of  Exciting Manufacturing

A tool logbook on paper is often not to hand just when you need it most. Or it is incomplete, since it is time consuming to keep the information up to date. A cloud-independent, electronic tool log, which is directly integrated into the tool could make all the relevant data available directly.

The Electronic Tool Logbook as a Combination of Operating Manual and Check List

Werkzeuginnendrucksensoren

Messtechnik

Sensoren / Messwertaufnehmer

Messdatenerfassung und -verarbeitung

Software

Papierlose QM-Dokumentation

Qualitätsmanagement

Dokumentationsmanagement

Werkzeugkonstruktion

Werkzeugüberwachung

Toolmanagement

Mobile Datenerfassung

Logistik

Lagertechnik

Digitale Transformation

Wirtschaft

Innovationen und neue Technologie

Werkzeug- und Formenbau

Fernwartung / Ferndiagnose

Instandhaltung

Dokumentenmanagement, CAQ

Qualitätssicherung

Data Management at the Tool

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.

Spritzgießsimulation

Simulation

Interview

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

Halbzeuge und Zwischenprodukte

Kunststoff-Halbzeuge

Verbundwerkstoffe / Werkstoffverbunde

A Bike Frame from an Injection  Molding Machine

Susanne Schröder will become editor-in-chief of the magazines Kunststoffe and Kunststoffe international on December 1, 2020. The current editor-in-chief Dr. Karlhorst Klotz will leave the company by mutual agreement.

Werkzeuge für Leichtbauwerkstoffe

Präzisionswerkzeuge

Tiefziehwerkzeug

Werkzeugwechselsysteme, Spritzgieß

Modulare Werkzeugsysteme

Absaugungen für Werkzeugmaschinen

Betriebsausrüstung / Betriebsmittel

Absaugvorrichtungen

Fluorkunststoffe

Thermoplaste

Werkzeugverwaltungssoftware

Prüfen von Kunststoffen

Biokunststoffe

Presswerkzeuge, Kunststoff

Werkzeugreinigung, Kunststoffe

Standardkunststoffe

Kunststoffverarbeitung

Lohnfertigung

Technische Kunststoffe

Füllstoffe für Kunststoffe

Kunststoff

Bauwesen

Baustoffe

Kunststoffhandel

Handel

Betriebstechnik für Kunststoffverarbeitung (Peripherie)

Kunststofffasern

Verstärkungsstoffe

Kunststoff-Recycling

Kunststoff-Aufbereitung

Hochleistungskunststoffe

Qualitätssicherung Kunststoff

Change in the Chief Editorial Office of Kunststoffe

At K 2019, the metrology experts at Kistler AG, Winterthur, Switzerland, showed how artificial intelligence will pave the way for the smart factory. ComoNeoPredict, a module of the ComoNeo process monitoring system, allows model-based prediction of the desired part quality based on the cavity pressure and temperature profiles. 

Kistler Puts Artificial Intelligence into Plastics Processing 

Networked Production with an Adaptive System 

An electric valve gate cylinder, which moves the valve pin directly, and in so doing sits on the manifold, is as compact and easy to maintain as conventional hydraulic cylinders, which would represent combining the best of both worlds. So does this work? 

Introduction of New Electric Valve Gate Cylinder 

Normalien und Heißkanaltechnik

Compact User-Friendly Electric Valve Direct Drive 

During this year’s pandemic, maintaining supply capability has become a key necessity among processors. Closer involvement of suppliers is only logical in these circumstances. In toolmaking, new challenges are emerging for services related to molds.

The Advantages of a Network for Global Qualification for Injection Molding

Erstbemusterung, Erstmusterprüfbericht

Werkzeugbau

Inline- / Online-Messsysteme

Fast and Effective Start of Production

A solution, which is unique in Europe, significantly increases productivity and comprises the production from a 12+12 stack mold with fully automated in-mold labeling and removal with visual 100 % inspection of the parts.

Fully Automated Production Line with Stack Mold and In-Mold Labeling

Heißkanalsysteme

Komponenten für die Kunststoffverarbeitung

Award-Winning Packaging Solution Increases Productivity

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.

Electrical Drives in Injection Molds

Elektrische Antriebe

Antriebe

Mess- / Regel- und Prozessleittechnik

Prozessautomation

Mess-, Steuer- und Regelgeräte

Medizintechnik

Reinraumsysteme / -technik

Medizinprodukte

Mold Technology

Increasing demands on component functionality and the need for efficient manufacturing processes are keeping multi-component injection molding squarely in the focus of plastics processing. Not all materials can be processed reliably in the desired combination. The new InMould-Plasma process, which is fully integrated into the injection molding process, facilitates more-efficient production and paves the way for completely new material combinations.

More Material Combinations,  Lower Costs

Thermoplastische Elastomere

Mehrkomponenten-Spritzgießen

Plasmabehandlung

Oberflächentechnik

Reinigen und Vorbehandeln

Dichtungsschäumen

Schäumen / Reaktive Verarbeitung

InMould-Plasma Streamlines the 2-Component Process and Expands  the Material Spectrum

Mold breathing provides useful information about the processes that occur in the mold and the cavity. Mold-maker Schneider Form and injection molding machine-maker Engel have recognized the potential which this process variable offers and have worked intensively on it for several years, albeit by adopting different approaches. They recently carried out joint tests on bumper molds using a two-platen injection molding machine with a clamping force of 40,000 kN and then swapped experiences.

Comparative Methods for Determining Mold Breathing

Energiemanagement / Smart Home

Installationstechnik

Industrie 4.0 für die Kunststoffverarbeitung

Industrie 4.0

Druck- / Kraftsensoren

Spritzgießmaschinen

Using Breathing Signals for  Process Optimization

The newly developed Compactcube mold system from Foboha can be used on slightly modified standard machines in the low to medium clamping force range. This means that the advantages of cube mold technology are now also available for applications with smaller production volumes.

Compactcube Reduces Initial Capital Outlay and Maintenance Requirements

New Application Areas for Cube Molds on Standard Machines

Ambient lighting has captured the car interior – and facilitated orientation for the passengers. There is no need for anyone to fumble for the seat belt buckle in the dark in the Audi A7, as an integrated light guide shows the way. Kunststoff Helmbrechts produces the 3-component part and also developed the tool concept. The trick:  a so-called twin-turn tool which rotates on both sides. The company was awarded the GKV TecPart Innovation Prize for it at the K 2019.

Twin-Turn Tool Provides Solution to Production Problem with a Double Turn

Polycarbonat

KFZ-Zulieferer

Runway Lights for the Seat Belt

Anyone seeking to replace a metal component by a plastic one, to reduce the number of component parts from eight to three and simultaneously cut both the weight and manufacturing costs needs to take great care to ensure that all specifications are met – especially if the component is used in a hot gearbox and is subject to high mechanical stress.

Production-Ready Plastic Shifter Fork Offers a Maximum of Functional Integration

Kohlenstofffasern / -matten

Produktentwicklung (F+E)

Innovationsentwicklung

Inserttechnik

Hybrid-Spritzgießen (Metall / Kunststoff)

Replacing Metal in the Gearbox

The Potential of Redesign and  Part Consolidation

Additive Manufacturing and Hybrid Molds in Combination with Conventional Machining

Hybrid production chains have been increasingly in the spotlight in recent years. This also applies to the combination of conventional manufacturing and additive processes in tool construction. With the example of an injection molding tool, it is shown how mold inserts produced by additive manufacturing can greatly shorten cycle times, and thereby significantly reduce unit costs. The important thing is to find a suitable combination of processes from the variety available.

Over recent years, additive manufacturing processes have greatly improved in terms of their performance, reliability and the range of materials available. There are many industrial applications now available and new ones are emerging all the time – as is shown by the examples during the Corona crisis.

However, it is also becoming clear that approval or certification is a stumbling block for rapid implementation in industrial series production. Especially where series production is concerned, not all processes are completely certified, or not all materials are available. This is because of the principle of layer build-up.

If 3D printing and conventional machining processes are combined with tool and mold making – the prerequisite is always adequate equipment and the corresponding expertise – then the disadvantages of part production in a hybrid production chain can be transformed into advantages by means of tool making.

Tools for injection molding elastomers, thermoplastics and thermosets have always been manufactured by the familiar material removal processes, such as lathe turning, milling and electrical discharge machining. Molds and mold inserts – which are for the most part subsequently hardened – have high surface quality, hardness and fatigue limit. The success here depends on many years of experience in the use of the tools. For example, with a long tool life, parts and components can be produced in uniformly high quality.

The Process Chain is Becoming  More Challenging

For many years, a switch toward smaller batch sizes and shorter availabilities has been apparent – with a uniformly high quality always being required. This results in a dilemma for mold makers, since tools manufactured faster (e. g. from materials that are easier to machine) offer a shorter lifetime. To compensate for this, new solutions, often more technically complex, are required. It is also necessary to call on new processes to find solutions that meet these challenging conditions.

Additive manufacturing (AM) – in particular metal layering processes – if correctly applied, offer many advantages for manufacturing tools, and allow unique features and functions to be realized, which were not conceivable until now (using conventional methods). However, these processes also have disadvantages in surface quality and in speed of manufacturing. Additive manufacturing proves to be a promising addition to conventional methods, particularly if it is combined with conventional methods such as HSC (high speed cutting), which, as is known, is suitable for rapid machining of surfaces. With this procedure, it is important to realize that, due to the combination of processes, the process chain is extended with an additional factor, but also becomes more challenging.

It is already becoming clear that there is no moldmaking process for rapid manufacturing of injection molds that could really satisfy all the demands. The conditions applying to machining only allow high-speed operation to a limited extent. 3D printing, by contrast, offers advantages that can be exploited if the correct process parameters and chains are chosen and can significantly improve the efficiency, despite process-dependent disadvantages in the surface structure and fatigue limit.

Given the aforementioned problems, Eisenhuth GmbH & Co. KG, Osterode, Germany, as part of the “KitkAdd” project, publicly sponsored by the BMBF (German Federal Ministry of Education and Research), after a great deal of creativity and empirical work, succeeded in developing the combination of mechanical tool manufacture and metal 3D printing into so-called “hybrid molding.” This approach essentially makes use of additively manufactured mold inserts, steel inserts manufactured by HSC, milled graphite electrodes and moldmaking standards, such as master molds, guide pillars and bushes (Fig. 1).

Each of these elements has positive material and manufacturing properties as a result of the process, which not only determine the injection mold but also its design [1] and construction. It is thus essential to combine the corresponding properties of the individual components and processes with one another. Combining the advantages of all manufacturing processes results in very efficient tools with their own unique features [2].

First the particular application must be described accurately. Based on their advantages and disadvantages, a strategy for utilizing the processes is created well before the design work is performed. The designer decides which parts are manufactured using which process, and which processes can be used. After the single part design has been completed, ready for manufacturing, the individual manufacturing steps are started simultaneously, even combining the individual manufacturing and secondary finishing processes. It is necessary to exercise especial care when planning and implementing this process. At the end, the parts are combined with one another and are available for production in a mold insert [3].

For all manufacturing technologies, the production parameters must be observed. For example, with HSC, the absolute material removal rates are relatively low, but very high strength materials can be machined. 3D printing offers advantages for complex structures and great geometrical freedom and flexibility, though, here too, the pitfalls lie in the details. Low build-up rates, and therefore a high price per built-up volume require the design to be adapted to AM in the early stages for the least possible material consumption.

Not all structures can be manufactured additively, so that, for example, small bridges, deep grooves or delicate structures can present difficulties. Since this is still dependent on the orientation of the part in the build chamber of the AM machine, the designer faces a particular challenge to produce designs suitable for manufacturing.

The advantage of the generative build-up of the metal tool components, namely the possibility of manufacturing extremely complex shapes, can also be utilized for combined application in electrical discharge machining. Thus, additively manufactured copper electrodes open up new machining possibilities here, and can supplement the graphite electrodes manufactured by HSC in the case of particularly difficult geometries.

In previous years, Eisenhuth gained a lot of experience in various industries with customer parts. The example of an injection mold for a simple part (Title figure) is used here to illustrate a suitable combination of processes from conventional and additive manufacturing. The part that is manufactured here is a spacer (Fig. 2) of a high temperature resistant, glass fiber-reinforced “triple-six polyamide” (PA6T/66, type: Grivory HT2V-3H, manufacturer: Ems-Chemie AG, Domat/Ems, Switzerland).

The aim of the project performed with this material is to examine what advantages can be achieved with AM parts, and how much influence additive manufacturing has on the cycle time, and therefore on the costs of the injection-molded part. And also to show that hybrid manufacturing is suitable and provides added value, even with comparatively simple parts [4].

The original approach was only to optimize the costs for the final serial part. However, since the spacer had already been optimized for series production (i. e. finalized) and could not be manufactured from the specified series material with the required strength, the workaround was chosen to optimize the tool in favor of shorter injection molding cycles. This was achieved using a temperature-control system with conformal cooling. It was also possible to reduce material consumption and therefore the costs for tool manufacture by means of a so-called “bionic design” [5].

The design of the mold insert is initially based on the target geometry, i. e. the original data set [5]. Implementation in 3D printing required one thing in particular: observation of the AM-specific design rules [1]. The ultimate design satisfied the loading, manufacturing and secondary finishing requirements for a mold insert that was produced by selective laser melting.

Due to the layer-by-layer manufacturing process, the design could be optimized during CAD, such that the mold inserts could be produced with approximately 35  % lower material consumption. As a result, the process time in the AM machine – generally the cost driver [6] – was also reduced, so that the manufacturing of the inserts was accomplished in less than two thirds of the time [5]. In addition, the hybrid-molding design was chose so as to keep the effort for secondary finishing as low as possible.

All these measures – especially the conformal cooling – increase the part complexity significantly. This highlights the big advantage of additive methods since, unlike conventional machining, the complexity here has only a very small influence on the costs (“complexity for free”) [4].

Comparison of Process Chains: Complexity Has no Extra Costs

Within the publicly sponsored “KitkAdd” project [7], Eisenhuth, together with one of the project partners, the Institute of Production Technology at the Karlsruhe Institute of Technology (KIT), developed a calculation tool for determining the manufacturing costs and times in production. The starting data can now be changed at any time, and since it can be almost precisely predicted how the changes each influence the result, the effectiveness of a measure can be derived.

The calculation tool is based on a detailed analysis of the different process chains (Fig. 3). This can be used to determine all the data and parameters that influence the mold and injection molded part costs, as well as the production times. From the result, the three possible variants – conventional, hybrid and additive process chains – can now be compared.

In this context, hybrid means a combination of a conventional tool with additively manufactured mold inserts. In the scope of the project tool, the project partner KIT also determined what costs are generated by a purely additive tool. Here it was found that there is no break-even, i. e. the 100  % additively manufactured tool is more economical than a conventional tool.

In a detailed analysis of the process chains, the tool costs for the two variants, the one- and two-cavity tool, are considered and this information is also incorporated into the calculation tool. As a result, it is found that the hybrid tools are about 35 % more expensive than the tools manufactured conventionally. This is primarily because of the increased manufacturing and secondary finishing costs of the additively manufactured inserts.

However the crucial factor is that the pure consideration of tool costs only covers part of the process chain, since with the use of hybrid tools, the production costs of the final parts are reduced. Consequently, after the tool costs, it is also necessary to determine the part costs for the two tool variants. The developed cost model not only supplies the pure costs for the basic tool and mold inserts, all the cost factors, such as the cycle time, are also considered.

This is also found in practice: In the case of additively manufactured mold inserts, the cycle time is shortened significantly (25 s instead of 38 s) due to the conformal cooling in contrast to mold inserts manufactured conventionally. This leads to a significantly higher utilization of the machines and increases the capacities: thus, e. g., for 100,000 parts, the break-even is reached even earlier (Fig. 4). Consequently, the part costs of the hybrid AM production chain for this two-cavity tool are reduced by about 2.5  % compared to a tool manufactured conventionally.

The example shows that despite the higher tool costs and the necessary secondary finishing work, the productivity for using hybrid tools is increased significantly while the part costs are simultaneously reduced. The prerequisites for this, however, are, first, a greater design effort and the necessity for comprehensive process knowledge of the – very different – methods used. In summary, it can be stated that the additive manufacturing of tools and tool inserts leads to significant technical and economic advantages for producers who are open to new ways of thinking and are not afraid of the effort.

1 Adam, G. A. O.: Systematische Erarbeitung von Konstruktionsregeln für die additiven Fertigungsverfahren Lasersintern, Laserschmelzen und Fused Deposition Modeling. Forschungsberichte des Direct Manufacturing Research Centers; Dissertation Universität Paderborn 2015

2 VDI-Richtlinie 3405 & VDI-Statusreport: Realität in der industriellen Fertigung. Beuth-Verlag, Berlin 2019

3 Gebhardt, R.: Detaillierte Roadmaps weisen Additive Manufacturing den Weg in die Smart Factory. VDMA, https://am.vdma.org/viewer/-/v2article/render/27025768

4 Klemp, E.: Prozessketten der Additiven Fertigung – Möglichkeiten und Chancen. Präsentation an der HS Lippe/Lemgo, 8. November 2019

5 Hickmann, T.; Wiedenegger, A.: Das Potential von Redesign & Bauteilkonsolidierung. Präsentation auf dem 4. AM-Forum Berlin,12. März 2020

6: Langefeld, B.: Advancements in metal 3D printing – Additive manufacturing on the brink of industrialization. In: Studie Roland Berger, Oktober 2018

7 Kombination und Integration etablierter Technologien mit additiven Fertigungsverfahren in einer Prozesskette. Projekt KitkAdd (www.kitkadd.de), gefördert durch das Bundesministerium für Bildung und Forschung, ISBN 978–3–00–065337–7

Wilhelm Eisenhuth GmbH KG  

www.eisenhuth.com

Ausgabenartikel

Tool insert for a spacer of a glass fiber-reinforced PA66. The example shows that hybrid manufacturing is suitable and provides added value, even with comparatively simple parts

Fig. 1. Apart from conventional tool building, hybrid molding also includes additively manufactured mold inserts and HSC milling 