Will the industry events announced for this fall now take place digitally, in hybrid form or actually face to face?

After two chaotic years, the show organizers, as well as visitors, still harbor this scintilla of uncertainty: will the industry events announced for this fall now take place digitally, in hybrid form or actually face to face? And we are in just the same position. A glimpse behind the scenes of the Kunststoffe editorial team.

When you hold this edition in your hands (or use the e-paper), the Kuteno regional trade show in Rheda-Wiedenbrück, Germany, will already be behind us. With the Special in this edition, we are giving you an extensive preview of Fakuma, which will kick off in October in Friedrichshafen, Germany. In planning this edition, we were hesitant at first. Will the show preview be 5 or even 30 pages? Will the trade show really be held live and in color? Eventually, we settled on 20 pages – filled with many innovations by the exhibitors. They demonstrate that there’s a lot to show. Even though in the past, there were more extensive reports of this kind. Most companies in the plastics industry have largely recovered from the effects of the corona pandemic – or even benefited from it. And many of them appear to be looking forward eagerly to meeting their customers in person again.

In the interview with Kunststoffe, Bettina Schall, who is in charge of Fakuma, puts it in a nutshell: “Of course, the trade show will be a bit sparser than usual because of the safety and hygiene regulations in force. But, this fall, it is not a matter of record figures but of personal attendance per se, and high-quality exchange.”

We can only endorse this. Instead of speed-dating and jostling, we will move around the show grounds in an orderly way, and perhaps make appointments in advance in a more goal-oriented way. But this very restriction reminds us yet again how valuable personal contact is. So in this spirit: Friedrichshafen, here we come!

16:9

Susanne Schröder [<a href="mailto:Susanne.Schroeder@hanser.de">Susanne.Schroeder@hanser.de</a>]

Editorial Schröder

User-Friendly Data-Exchange in the Digital Engineering

Part 6 of the Series: How a Web-Based Interface Supports Data-Handling

The multitude of software applications often requires the handling of information in different data formats. It is not uncommon for information to be lost in the process, which is why PIC 4.0 is researching methods for implementing continuous simulation chains.

Digital engineering encompasses the complete development chain of a product, from quality requirements to the design of the product and mold, to process simulation and design. The multitude of software applications often requires the handling of information in different data formats. It is not uncommon for information to be lost in the process, which is why PIC 4.0 is researching methods for implementing continuous simulation chains.

In digital engineering, the properties of a product to be developed are simulated and digitally optimized by a digital but physically adequate representation, taking into account the manufacturing process. The consistent use of digital methods and corresponding software (CAx) increases the planning quality along the entire product development and production process [1].

Due to the complex planning and calculation methods in the respective stages of product development (Title figure), many software applications are used. On the one hand, the applications are specialized in the simulation at the respective stage and therefore process specifically provided information. On the other hand, the users are also often specially trained in the use of these programs and their evaluation. As a result, data handling across different formats and planning stages – especially in case of iteration loops across domain boundaries – is often challenging.

Loss of Information by  Software Combination

One use case is the linking of a computational fluid dynamics (CFD) simulation with structural simulation (Fig. 1). Simulation programs specialized in injection molding use STEP files (*.stp, *.step), stereolithography files (*.stl) or a variety of other geometry data in their own and further established formats to generate a calculation mesh suitable for the simulation case. They determine the expected temperature and pressure distribution, provide a filling pattern including the expected defect features (e. g. weld lines) and calculate properties such as shrinkage, warpage, fiber orientation and residual stresses.

The mesh of structure simulation, on the other hand, can be generated differently in terms of shape and granularity of the elements. In order to make comparisons, the meshes must be mapped to each other, e. g. the nodes and edges of the rigid calculation mesh of a filling simulation must be assigned to the more flexible meshes of a structure simulation in order to consider a mechanical load. A loss of information occurs if interpolation is necessary between nodes of one and another mesh, e. g. due to deviating granularity.

Even when mapping between selected programs and formats using commercially available interface programs, information about the granularity of the output mesh is often lost after interpolation or after rounding of edge lengths in the output mesh. Here, it is necessary to keep track of the output mesh as well as basic mesh information such as the size, order and shape of the elements and the structure of a mesh at the respective stage of development.

Development of a User Interface to Facilitate Data Handling

One solution for a user-friendly data handling is a web-based user interface newly developed as part of the Plastics Innovation Center 4.0 (PIC 4.0) research project. It accesses a database with available simulation files and provides insight into how calculation meshes change in the product development process. In addition, it supports simulation and production processes by generating test plans and automatable optimization routines directly from the application.

For the targeted development of the user interface, a specific use case is considered in which a product for optical applications is to be designed according to defined requirements [3]. This concerns the material selection and the product geometry as well as the manufacturing process. The high requirements on the thermo-optical design of lenses often require a complex development process involving many iterations. Even if the first products have already been produced, the mold geometry often still has to be digitally measured and adapted accordingly. In addition to process simulation in software applications such as Moldex3D, the project focuses also on structure simulation using Ansys or Abaqus to design the optical properties.

From Uploading Geometry Files to Finally Export Machine Settings

The web-based user interface developed in the JavaScript web framework Vue.js (Fig. 2) simplifies the setup of an injection molding simulation in a selected application. It also supports the optimization of setting parameters through the automated evaluation of simulated design of experiments (DoE). The web application guides the operator from the initial upload of several geometry files for part, sprue and cooling channel layout through the entire development process to the export of a machine settings of a desired target machine (module area).

Available models and target applications are displayed in the project preview so that the dataset can be obtained directly via the user interface (simulation setup  download simulation). If a corresponding dataset is not yet available for the requested simulation software, it can be generated via the interface (simulation setup  create simulation). Some basic information about the available datasets is displayed directly in the preview area (part information).

To set up a new simulation project, corresponding files are first uploaded to the user interface via the geometry import and assembled into a simulation project for the target application. For this purpose, the individual geometry data for the component, cooling channel layout or sensor positions are combined in a project file suitable for the target application. After the gathered master data for the simulation project as well as the mesh information have been transferred or manually adapted, the project and geometry files are stored in the object database MinIO of MinIO Inc. (USA). Thereby, they are available for further processing of the parameter and structure optimization in the geometry module of the web application.

Optimization of Quality Models and Neural Networks

As soon as the geometry data is available, a trial plan can be generated via the DoE-module in order to determine and analyze the effects of relevant parameter variations by simulation. For this purpose, the user interface generates a trial plan in the background based on the desired factor combination and simultaneously triggers simulation tasks for the respective trial points. These are sent directly to the selected simulation program via the interface to set up and start simulation of trial points independently of the target application in the user interface.

The corresponding module enables the optimization of the setting parameters and generation of machine-settings on the basis of the simulated test plans. On the one hand, optimization based on quality and process models from statistical analysis is planned, and on the other hand, data-based optimization, e. g. with the aid of neural networks.

In the module for geometry optimization, the automatable iteration of the process and structure simulation is carried out up to the simulated ideal of the component geometry. Each iteration includes both the necessary mapping of the calculation meshes to each other and the storage of the meshes with the relevant mesh information. This ensures that changes in the calculation mesh can be tracked by the mapping and that it is possible to jump to any point in the iteration. The final geometry as well as the recommended process settings are conclusively displayed in the module.

Data Standards Enhance  Individual Workarounds

The web-based user interface is already capable to connect to the Moldex3D simulation environment. Simulation projects can thus also be created and initiated outside the actual simulation application. Due to the modular character of the user interface, the implemented methods can also be individually further developed and reused, for example to send parameter combinations of a simulated test plan directly as an order to the injection molding machine.

In the following, the PIC 4.0 also focuses on the integration of the potential data standard VMAP, which was developed by industry representatives along the value chain in a research project “Virtual Material Modeling in Manufacturing” completed in 2020 [4, 5]. It is intended to facilitate the consistent exchange of information between applications in digital engineering and thereby further increase the functionality of the user interface. Thereby, information about the calculation mesh might automatically be extracted by the presented user interface without the necessity of application-specific formats or converters. At the same time, a unified data format like VMAP might support automation of a quality-oriented data exchange and comparison between models in digital engineering and high-frequent data from real production processes.

[1] Schumann, M.; Schenk, M.; Schmucker, U.; Saake, G.: Digital Engineering – Herausforderungen, Ziele und Lösungsbeispiele. In: Schenk, M. (Hrsg.): Digitales Engineering und virtuelle Techniken zum Planen, Testen und Betreiben technischer Systeme, 14. IFF-Wissenschaftstage 28.-30.06.2011, pp. 191–200

[2] Balcerowiak, D.: Entwicklung eines geschäumten, thermoplastischen und lokal endlosfaserverstärkten Leichtbauteils sowie Konzipierung der erforderlichen Werkzeugtechnologie und Fertigungszelle mit variantenreicher Produktion. Masterarbeit, RWTH Aachen 2016

[3] Hopmann, C.; Loosen, P.; Stollenwerk, J.; Liu, B.; Gerads, J.; Hofmann, J.: Kunststofflinsen im Laser sind möglich. Gekoppelte Prozess- und thermooptische Auslegung. Plastverarbeiter 72 (2021) 4, pp. 22–25

[4] Fassas, A.; Mokios, G.: Mapping made easy: How the new VMAP interface standard can be utilized in ANSA towards smooth preprocessing. In: N. N. (Hrsg.): NAFEMS World Congress 2019. Québec City, Canada 2019

[5] Liebold, C.; Haufe, A.; Vinot, M.; Holzapfel, M.; Dittmann, J.; Böhler, P.; Fritz, F.; Finckh, H.: Lessons Learned from Developing a Digital Prototype within the ARENA 2036 Environment and Improvements with the new VMAP Standard. In: N. N. (Hrsg.): NAFEMS World Congress 2019. Québec City, Canada 2019

Stages of an exemplary product development process for a load-balanced saddle equipped with different tapes

Fig. 1. Linking CFD and structure simulation to get an ideal product design [2] 

Fig. 2. The web-based user interface supports initializing an injection molding process simulation independent from the target application 

Name - Hauptartikel

Univ.-Prof. Dr.-Ing. Christian Hopmann has held the Chair of Plastics Processing as Head oft he Institute for Plastics Processing (IVK) in Industry and Craft at RWTH Aachen University, Germany, since 2011.

Pascal Bibow, M.Sc. RWTH, has been working since September 2016 on intelligent production systems at IKV. Since January 2020, he has been managing director of the Plastics Innovation Center 4.0; <a href="mailto:pascal.bibow@ikv.rwth-aachen.de">pascal.bibow@ikv.rwth-aachen.de</a>

Ben Liu, M.Sc. RWTH, has been working since April 2019 on automated data exchange for targeted analysis with respect to Digital Engineering in injection molding.

The construction of the Plastics Innovation Center 4.0 is funded by the State of North Rhine-Westphalia and by the European Regional Development Fund (ERDF).

In the following article, the authors report about digital shadows from setting up and testing initial PIC 4.0 Testbeds, as well as their storing and processing by smart agents. It will be published in one of the next issues. The previous part has been <a ext="tango:{f0232aa8-a74c-4078-9146-8ea0ebb04235}">published in issue 5/2021</a>.

<a href="http://www.ikv-aachen.de/forschung/efre-pic-40/" target="_blank">www.ikv-aachen.de/forschung/efre-pic-40/</a>

Digitale Transformation

Wirtschaft

Innovationen und neue Technologie

Simulation

Software

Spritzgießsimulation

Industrie 4.0 für die Kunststoffverarbeitung

Industrie 4.0

Virtual Reality für die Qualitätssicherung

Industrie 4.0 für die Qualitätssicherung

Implementation of Industry 4.0 in Injection Molding and Compounding

Part 1 of the Series: Use Cases Based on Strategic Priorities in Plastics Processing

Based on interviews in industry, this article describes a common understanding of the most important use cases. The results capture the current direction in the plastics industry.

The challenge in digitalization is to maintain an overview of possible technologies and to identify their benefits for use cases in the own company. Small and medium-sized companies in particular find this difficult. Based on interviews in industry, this article describes a common understanding of the most important use cases. The results capture the current direction in the plastics industry.

Industry 4.0 covers a wide range of possible technologies and applications. This increasing digitalization is opening up new opportunities for production companies. Within the framework of a three-part series of articles, the challenges of implementing Industry 4.0 in the area of injection molding and compounding production technologies will be highlighted. In this first article, the focus lies on the use cases of Industry 4.0. The question is how to identify the use cases that are relevant for a company. A focused and targeted approach based on specific use cases has proven to be promising. However, the challenge usually lies in the diversity and complexity of the different use cases. Here, a common understanding of the definition of the relevant use cases is a central point. In most cases, they form the basis for the data acquisition requirements, including the development of the necessary IT infrastructure. This view of the use cases essentially shows which signals have to be recorded and in which quality they must be available. This basis shows companies how artificial intelligence can be used to learn from the data of the specific case.

More about this topic will follow in the next two articles in this series. In this first article, an approach for the identification of use cases in plastics processing is presented. The results are identified use cases based on the strategic priorities of the manufacturing companies.

Digital technologies form the core of Industry 4.0 and the basis of the many different use cases that result from it. When networked products and machines grow together in production, this leads to a smart factory [1]. Cloud computing or IoT predictive maintenance are just some of the technologies mentioned in this context [2]. There are also various approaches to implementing Industry 4.0 in the field of plastics processing [3]. The challenge is to maintain an overview of possible technologies and to derive their benefits for individual use cases for one’s own company. Closely linked to the effective benefit of a specific use case is the relationship to corporate strategy.

Furthermore, the existing IT infrastructure of the companies will influence the further development and the identification of new use cases. A 2018 survey of Swiss manufacturing companies shows that small and medium-sized enterprises (SMEs) in particular are reluctant to implement digital technologies [4]. The variety of possible technologies overwhelms small and medium-sized enterprises in particular in identifying the use cases that are relevant for them. The study also shows that the focus of smaller companies lies on increasing sales, whereas medium-sized companies are concerned with increasing efficiency. Companies with a size of 500 employees want to increase both sales and efficiency by selecting suitable use cases [5]. This gives first indications, where the focus of possible use cases lies.

The structured approach in the identification of suitable use cases enables companies, based on strategic priorities, to identify technologies for their own production. This article is based on the use case framework for the smart factory [6]. Table 1 shows the procedure structured in six steps for the evaluation of suitable use cases.

The framework shows small and medium-sized companies in particular how to quickly identify potential use cases. With the help of the generic use cases, a common understanding can be built up and the question of the appropriate implementation of digitalization measures can be discussed. The most targeted use of the required resources is related to the maturity of the infrastructure and the processes of the company.

In order to identify the relevant use cases in the field of injection molding, five companies were surveyed on the generic use cases. The results should be viewed critically as the sample can not be regarded as representative of the basic industry population. The results of this article are mainly suitable for highlighting general trends.

The interviews focused on the current status of already realized implementations and the potential benefits in the future. The participants of the survey is composed of the following companies in the value chain of the plastics industry:

<ul><li>suppliers of sensors and measuring systems (1),</li><li>machine manufacturer (2), and</li><li>processing industry (2).</li></ul>

By selecting companies along the value chain, the priorities can be shown for the plastics industry. The various people interviewed were each asked to take the point of view of the processing industry, so that agreements can be shown with regard to the prioritized use cases. The following results claim to capture the current direction in plastics processing.

With the definition of the strategic priorities and the resulting core processes, the common consensus on the most important use cases can be established. Figure 1 illustrates the common view of the companies surveyed with regard to the potentials and the current status of their implementation. The use case framework for the smart factory can be used to draw conclusions about relevant use cases based on the corporate strategy.

The evaluation revealed a common consensus on seven use cases. All of these show high potential. The exact definition of the use cases is recorded in Table 2. The two use cases “Remotely guided operations” and “Remote maintenance assistance” have already been partially implemented and ensure the decentralized exchange of knowledge between machine manufacturers and the manufacturing industry.

The remaining five use cases are being tested for implementation on the basis of preliminary studies or concepts. The survey showed that the trend is toward “autonomous process optimization”, with this use case representing the highest level of maturity in the framework. The common effort towards the reduction of downtime leads to the optimization of process efficiency via clearly defined fault conditions. The integrated data flow via a central database provides the basis for implementation. The goal of autonomous process optimization at the machine or plant level requires that both the transmission and the analysis of the parameters are mastered.

The interviews showed that the companies are already working on many use cases. However, the knowledge learned usually remains with the project team involved. As a result, it is difficult for the companies to record progress in terms of implementation.

The presented framework supports the prioritization of use cases as well as the implementation based on the specific context in the companies. The results of the six process steps are developed by a project team. The common understanding leads to an early clarification of what influences the implementation and what advantages are achieved in terms of costs, quality, delivery reliability and flexibility. The multi-stage approach in conjunction with clear strategic goals means that existing knowledge can be built upon through previous projects. The definition of specific use cases is of central importance when talking about the same throughout the company. In general, the identification of use cases should be carried out using a defined method in order to deploy resources in a targeted manner.

[1] Classen, M., Blum, C., Budde, L., Hänggi, R. & Friedli, T. (2018). Digitalisierung à la carte. ZWF Zeitschrift für wirtschaftlichen Fabrikbetrieb, 113(12), 850–854. https://doi.org/10.3139/104.112016

[2] Friedli, T., Benninghaus, C., Elbe, C. & Remling, D. (2018). Swiss Manufacturing Survey 2018 – A national study. Final Report.

[3] Hopmann, C. & Schmitz, M. (2021). Plastics industry 4.0: Potentials and applications in plastics technology. Hanser Publishers; Hanser Publications.

[4] Huber, W. (2018). Industrie 4.0 kompakt – wie Technologien unsere Wirtschaft und unsere Unternehmen verändern: Transformation und Veränderung des gesamten Unternehmens. SpringerLink Bücher. Springer Vieweg. https://doi.org/10.1007/978–3–658–20799–1

[5] Kagermann, H., Helbig, J., Hellinger, A. & Wahlster, W. (2013). Umsetzungsempfehlungen für das Zukunftsprojekt Industrie 4.0: Deutschlands Zukunft als Produktionsstandort sichern ; Abschlussbericht des Arbeitskreises Industrie 4.0. Forschungsunion. https://books.google.ch/books?id=hzmFoAEACAAJ

[6] Lichtblau, K., Bertenrath, R., Millack, A., Schröter, M., Institut der Deutschen Wirtschaft Köln und FIR e. V. an der RWTH Aachen, Schmitz, E., Stich, V., Bleider, M., Blum, M. & Schmitt, K. Industrie 4.0-Readiness (FIR – Forschungsinstitut für Rationalisierung e. V RWTH-CONV-207822). <a href="https://publications.rwth-aachen.de/record/569389">https://publications.rwth-aachen.de/record/569389</a>

Table 1. Procedure steps for the use case evaluation

Table 2. Description of the generic use cases

Source: based on Classen et al., 2018; graphic: © Hanser

Ostschweizer FH - Hauptartikel

Adrian Rüedy, M.Sc., is project leader at the Institute for Product Design, Development and Construction (IPEK) at OST – Eastern Switzerland University of Applied Sciences.

Prof. Dr. Roman Hänggi is a partner at the Institute for Product Design, Development and Construction (IPEK) and Professor for Production Management at OST.

Dr. Lukas Budde is a post-doc and project leader at the Institute of Technology Management (ITEM) at the University of St. Gallen (HSG).

Prof. Dr.-Ing. Frank Ehrig heads the Institute for Materials Technology and Plastics Processing (IWK) at OST.

Curdin Wick, M.Sc., is head of the injection molding department at the Institute of Materials Technology and Plastics Processing (IWK) at OST.

Prof. Daniel Schwendemann is head of the compounding and extrusion department at the Institute of Materials Engineering and Plastics Processing (IWK) at OST.

The following two articles highlight the challenges of implementing specific use cases and learning from data using artificial intelligence in the field of the production technologies injection molding and compounding.

Strategie und Organisation

Spritzgießen

Kunststoffverarbeitung: Verfahren

Compoundieren

Kunststoff-Aufbereitung

Fakuma 2021: Trade Meeting in Friedrichshafen from October 12th to 16th

Due to current requirements, the aisles will be wider and the halls “somewhat more airy”, as Kunststoffe was told by exhibition manager Bettina Schall.

Due to current requirements, the aisles will be wider and the halls “somewhat more airy”, as Kunststoffe was told by exhibition manager Bettina Schall. This year’s autumn exhibition will not focus on record numbers – in the foreground will be the physical meeting at a presence event. Apart from the topics of injection molding, thermoforming, extrusion, and 3D printing, circular economy will also play a significant role.

Exhibitors and trade visitors are eagerly awaiting the 27th Fakuma in Friedrichshafen, Germany. In addition to further developments in the digital transformation of the plastics processing industry, the exhibition will focus on the change from linear to circular economy.

“At long last, exhibitors want to show their novelties live again”, says Bettina Schall, manageress of P.  E. Schall GmbH & Co. KG. “That’s why users and customers are looking forward to the hands-on presentation of new products and technical solutions.” As an established trade fair for injection molding, extrusion technology, thermoforming, and 3D printing, the Fakuma wants to show that much has been achieved in machine and product development as well as improvements in processing and processes.

For machine manufacturers, users, and end customers, the current range of products and services offers new approaches and solutions in the fields of sustainability, environmental protection, recycling, and circular economy. Apart from production efficiency, the exhibition also addresses the conservation of resources and the indispensability of plastics in the attempt to reach the climate change targets. “It can be felt clearly that exhibitors are increasingly taking steps to counter the unfortunately negative image that plastics have”, says Annemarie Schur, Fakuma project leader. “The Fakuma will contribute towards providing more detailed information about circular economy, recyclability, product life cycles, and product design.”

… Bettina Schall, manageress of exhibition organizer P. E. Schall GmbH & Co. KG

A presence exhibition again at last! What is your personal highlight hereby?

For me, the Fakuma is a highlight itself. Because I am very pleased that we have overcome the event-free period, and that exhibitors can personally meet with their customers again.

How many exhibitors have booked? Are all the halls occupied?

All halls are occupied. We will experience a well-visited Fakuma, which will obviously be somewhat more “airy” than usual, due to the applicable protection and hygiene regulations. But the exhibition this autumn is not focused on record numbers, but on presence as such, and on a qualitatively high-grade business exchange.

What will be different in the halls because of Corona regulations?

The Messe Friedrichshafen has a protection and hygiene concept that we fully observe. The concept regulates all individual measures – they have been agreed with the authorities, and are based on the Corona Act passed by the federal state of Baden-Württemberg, Germany. Within the scope of this concept, personal business contacts and the exchange between experts on equal footing are possible, and that is what counts now!

Has the “one year break” changed the exhibition’s focus?

The Fakuma’s main topics remain the same. But of course, the industrial sector has progressed in many areas. For example, increasing digitalization and automation provide opportunities for better sequences, improved efficiency, and higher productivity. Simultaneously, plastics processors are faced by the change from a linear to a circular economy. We will also frequently come across the subjects of recycling and product design. In this context, we are sure to see and experience many exciting novelties during the exhibition.

Bettina Schall, Fakuma exhibition manageress

Preview Fakuma - Hauptartikel

International trade fair for  plastics processing

<a href="http://www.fakuma-messe.de">www.fakuma-messe.de</a>

Messe Fakuma

kunststoffe-international.com

From Injection Molding to  Additive Manufacturing

PA66 and PBT considerably expand the field of applications for laser sintering by showing better properties than classic PA11 and PA12 materials in most cases.

The implementation of series applications in laser sintering is currently still hindered by an insufficient variety of materials. Many important engineering materials from traditional plastics processing have only been available for the process to a restricted extent up to now. PA66 and PBT considerably expand the field of applications for laser sintering by showing better properties than classic PA11 and PA12 materials in most cases.

Additive manufacturing of plastics, and laser sintering in particular, has developed into a series production process in recent years. The production of millions of mascara brushes [1] and tens of thousands of glasses frames [2] are examples of this and show that even large quantities can be produced cost-effectively and in high quality. A major advantage of laser sintering is that standard thermoplastics can be processed with high part quality and close to injection molding properties. Although the process has become well established, the choice of materials is still limited. Various materials, especially semi-crystalline ones, are meanwhile available, but most of these are still niche products.

The market is currently still dominated by polyamide 11 (PA11) and PA12. With these polymers, the process has reached a good technical maturity. However, both are not dominating materials in traditional plastics processing. Plastics such as polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC) and acrylonitrile butadiene styrene (ABS) have significantly larger market shares. Even among polyamides, PA6 and PA66 dominate over PA11 and PA12, making them niche materials in classic applications.

For this reason, the step into additive manufacturing remains unavailable for many classic application areas due to a lack of suitable materials, although many interesting application areas would be available, for example, in the automotive, aerospace, electronics and electrical and mechanical engineering sectors. However, many companies hesitate to change the manufacturing process and material in one step. The effort required to introduce additive manufacturing is often considered too high to consider a second variable in the form of a previously unused material. As a result, many potential series applications remain closed, even though the number of units and the area of application would be suitable in principle.

A rethinking process has therefore taken place in the industry in recent years. Developments using additive manufacturing are being planned and initiated, claiming a clear break with widely available PA11 and PA12. The focus of this trend is additive manufacturing with the materials that have already been used for the application. The requests for additional materials for additive processes are therefore becoming louder.

However, the development of materials for laser sintering or powder bed fusion is usually very complex. The requirements for the materials and the manufactured components are based on the reference materials for injection molding. However, both processes differ fundamentally with respect to the required material properties and are usually even contrary with respect to these requirements (for more details [3, 4]). While rapid solidification and short crystallization times are desired in injection molding, these complicate processing in laser sintering. In addition, there is the need for a wide processing window between melting and crystallization, which only a few semi-crystalline materials provide as standard. Further complications arise from the lack of process pressure to support forming, and the difficulty of producing powders with good flowability and suitable particle size distribution. The combination of these requirements has in the past, and still currently, resulted in many materials with poor processing or part properties. Poor experience among users has often led to rejection of alternative powder materials to PA11 and PA12, thus hindering the necessary market distribution.

Traditional Plastics for  Additive Manufacturing

AM Polymers has addressed this problem in particular, developing well-known standard thermoplastics and engineering plastics from injection molding for laser sintering with a focus on plug-and-play solutions. Over the last few years, this has resulted in various powder materials based on thermoplastic polyurethane (TPU), PE, PP, PBT and PA6, which are distributed under the brand name Rolaserit. They are characterized by part properties comparable to injection molding and good processing behavior with high elongation at break and good batch-to-batch reproducibility. Special focus is placed by the company on short run-in times of just a couple of days through support with extensive processing know-how, so that customers can quickly go into part production.

With Rolaserit PA66–01, AM Polymers is now announcing for the first time a PA66 powder material for the laser sintering process. Compared to other polymers, PA66 is characterized in particular by high heat deflection temperature and aging resistance. At the same time, the material exhibits high hardness and stiffness as well as good abrasion resistance. These properties make the material particularly suitable for molded parts subjected to high mechanical and thermal stresses in electronics as well as in mechanical engineering, automotive applications and apparatus manufacturing. Typical components made of PA66 can be coil bodies, plain bearings, gears, coupling parts, but also coverings and housing parts [5, 6].

The material was developed as part of the Flatisa joint project funded by the German Federal Ministry of Education and Research (BMBF) via the Projektträger Jülich as part of the Promat_3D call (funding reference number 03XP0099F) in cooperation with Airbus and Siemens. It has already been successfully tested at the last mentioned companies for the production of demonstrators for the aerospace and electronics industries (Title figure and Fig. 1).

The material exhibits PA66 typical component properties with an elastic modulus of 3100 MPa, a strength of 75 MPa and an elongation at break of up to 15 % in dry state. In addition, the material meets a fire protection classification according to UL94 V2. In a first commercialization step, the material will be made available to the user market as part manufacturing on equipment from AM Polymers. The material shows very good processability on a laser sintering system (type: ST252P, manufacturer: Farsoon Europe) and also allows fine details due to its good ductility. Due to the high melting temperature, suitable machines with sufficiently high processing temperatures are required for processing. Such machines, however, are not yet very widespread. The range of suitable machines available from various machine manufacturers is increasing steadily, however. In the future, it can therefore be assumed that PA66, like other materials for laser sintering, will be widely available on the market.

As a further new product development, different PBT grades for use in laser sintering were jointly developed by AM Polymers and Mitsubishi Chemical. PBT as a polymer is characterized in particular by good slide and wear properties, good electrical insulation properties independent of moisture absorption, and high dimensional stability. Typical applications include plain bearings, valve moldings, rollers, pump housings, impellers, couplings and, in particular, applications in the electrical industry such as coil bodies, clamp and connector blocks [5, 6].

The typical melting temperature of PBT is 223 °C and thus normally requires powder bed temperatures above 200 °C for laser sintering. The material commercialized under the product name Rolaserit PBT01, on the other hand, can be processed on all standard types of laser sintering machines. The material has, for example, already been successfully processed on systems of type ST252P from Farsoon Europe, Vanguard HS from 3D-Systems, EOS P360 from EOS. Therefore, there are no restrictions with regard to the machine technology for a wide range of applications.

Compared to PA12, the material is characterized in particular by a higher stiffness of 2650 MPa at a strength of 48 MPa, as well as lower moisture absorption and thus moisture-independent material properties. Elongation at break of up to 15 % is achieved in laser sintering, which is about the same as for PA12. Even without post-treatment, the material has a high-quality, very smooth surface. This can be further improved by chemical post-processing through vapor smoothing (Fig. 2). The material also has very good electrical insulation properties. The surface resistance is 5  ·  1016 Ωm and the volume resistance is 3  ·  1015 Ω, which is a potency higher than that of classic injection molding materials made of PBT. These properties make the material very suitable for electrical and electronic parts, as illustrated by the application for a special connector (Fig. 3). Due to the high component ductility, it was also possible to produce fine details and snap-on connectors of suitable quality. This was confirmed by application and function tests.

On the base of this basic grade, further filled versions were developed, which again significantly extend the application spectrum of PBT for laser sintering. In a first step, glass fiber and carbon fiber filled grades were considered. For the first time, fiber-filled PBT-based materials were successfully introduced in laser sintering. Filling with fibers once again significantly improves the material properties. The stiffness could be increased to 5500 - 6000 MPa and the strength to up to 60 MPa, while the temperature resistance could be increased to 180 °C. By suitable preparation of the materials, it was possible to prevent any deterioration in processing behavior despite the use of fibers. Thus, a good powder spreading is given despite the use of fiber fillers.

Additive manufacturing and in particular powder bed fusion processes such as laser sintering are becoming increasingly important for use as series production techniques. However, in many cases the use in series production requires the appropriate materials, which are already used today in injection molding in the corresponding applications. However, these are often only available for additive manufacturing to a limited extent. AM Polymers is addressing this point and making traditional injection molding materials with application-specific properties available for laser sintering. This should create a comparable range of materials for laser sintering in future.

[1] Lai. E., Chanel announces plan to mass-produce a 3D printed mascara brush. 3d Printing Industry, 20th March 2018.

[2] Bräunlein, J.: 3D-Druck: Augenoptik im Umbruch?. eyebizz, 6 (2016).

[3] Alscher, G.: Das Verhalten teilkristalliner Thermoplaste beim Lasersintern, PhD thesis, University of Essen, 2000.

[4] Schmachtenberg, E., Seul, T.: Model of Isothermic Laser-Sintering, Proceedings of the Antec Conference 2002, San Francisco Kalifornien, Society of Plastics Engineers, 2002.

[5] Domininghaus, H.; Elsner, P.; Eyerer, P.; Hirth, T.: Kunststoffe – Eigenschaften und Anwendungen, 7. Edition, Berlin – Heidelberg, Springer-Publishing, 2008.

[6] Baur, E.; Brinkmann, S.; Osswald, T.: Saechtling Kunststofftaschenbuch, 30. edition, Munich, Carl Hanser Publishing, 2007.

As a temperature-resistant and flame-retardant material with high mechanical properties, PA66 opens up new application possibilities for laser sintering, such as its use as a sensor holder

Fig. 1. Functional demonstrator of an electronic component made of PA66 produced by laser sintering: the material offers itself as an alternative to PA11 and PA12 in many areas

Fig. 2. Components made of PBT produced by laser sintering already have a very smooth surface after printing (left). Vapor smoothing can subsequently improve the surface quality even further (right)

Fig. 3. Laser-sintered special connector with clips and thin connector elements made of PBT: due to its electrical insulation properties, the PBT type used is very well suited for such components

KU 9-21_AM Polymers - Hauptartikel

Dr. Andreas Wegner is co-founder and CEO of AM Polymers GmbH; <a href="mailto:a.wegner@am-polymers.de">a.wegner@am-polymers.de</a>

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Additive Fertigung

NP Germany: Extraordinary Turnkey System for Automotive Products

NP Germany’s turnkey system around a vertical Arburg injection molding machine takes up a quarter of the production hall.

A more impressive sight is scarcely imaginable: NP Germany’s turnkey system around a vertical Arburg injection molding machine takes up a quarter of the production hall. During operation, six robotic systems dance a ballet to produce a pump impeller for the car coolant pump of an international automotive supplier – a level of fully automated production that was not an everyday occurrence.

Benedikt Niglis, head of project at NP Germany in Brilon, Germany, says he put several years of his professional engineering life into the project. And the result is really something to be proud of, he adds with conviction. The system is used to produce a pump impeller for a high-output car coolant pump, which can be used to cool vehicle components such as battery packs for hybrid vehicles.

One requirement for the turnkey system (Title figure) was to automate as many work steps as possible up to the finished product while maintaining a high level of autonomy through buffers. Another aspect of the system‘s great flexibility is its ability to run processing steps manually and to decouple the two aspects of injection molding and ultrasonic welding so that malfunctions in the welding cell do not lead to an interruption of the injection cycle.

NP Germany, founded in 1851 and member of the Clayens NP Group since 2012, and Arburg decided to integrate a vertical injection molding machine, type Allrounder 1500 T, because the machine‘s vertical mode of operation ensures that the inserts remain precisely positioned in the mold. The cycle time also plays a major role and has been shortened by more than 6 s compared with the horizontal concept. Even with all the different inserts, the electric two-station rotary table, on which there are two identical ejector sides, each with four cavities, saves valuable time as loading takes place at the same time as the spraying cycle.

The vertical machine is the first machine of its kind to be integrated into the production process at NP Germany. Initial concerns due to the complex handling processes were quickly dispelled by working with the Selogica controller, whose user interface was also implemented on the controller of the three Kuka six-axis robots involved in the process. The gradual ramp-up phase is scheduled for the second half of 2021.

Filigree Pockets Filled by High  Injection Flowrates

Two versions of the pump impeller made of PPS with 40 % glass fiber content are produced on the line. They are differentiated by the length of the integrated magnets and punch packs. In this way, the product is divided into two performance classes. Two hot runner molds with needle-type shut-off nozzles and four cavities each stand ready for each version. Before the cycle actually begins, a bearing bush and a rotor pack are inserted into each of the four cavities on the free side of the rotary table, into each of which six magnets have previously been automatically pressed. One special feature is the ejector side of the three-platen molds where, in addition to the mechanical slides, there are ejectors, which are used to precisely position the rotor packs to be overmolded using a core pull after the mold has been closed.

A six-axis robot removes these supply parts from a load carrier on a tray server, positions them correctly and transfers them to a preheating station. A linear robot system (Multilift V 30) collects the rotor packs from the heating station (Fig. 1). Prior to this, the bearing bushes had been received as bulk material. At the end of the cycle, the three-axis robot first removes the molded parts from the rotary table and then loads the cavities with the inserts. Since the punch packs have very filigree pockets through which the material must flow to fill the lower lid, this requires a high injection speed. After the injection molding process, the second handling unit removes the sprue tree.

The molded parts that have been re-moved are transferred to a camera inspection station, which checks their top sides for molding defects. The second six-axis robot takes charge of the parts and guides them to another camera station where their under-sides are also checked (Fig. 2). The molded parts are then placed on a double sliding table and leave the system in the direction of the welding cell. Once there, they are removed from the double sliding table by the third Kuka robot. The robot then collects lids, which are provided as bulk material via a vibratory bowl.

The lids are also turned out in the correct welding position by the six-axis robotic system before collection by a third linear handling system. Before the molded parts are transferred to the welding station (Fig. 3), the finished parts are removed. The six-axis robot then loads the welding station again and packs the finished parts on a load carrier, which is likewise supplied by a tray server. These then go directly to the customer.

Besides the fact that Arburg was able to provide all the components required for the turnkey system in cooperation with proven partners, NP Germany also appreciates “Arburg‘s cooperative approach, the standardized operation of its systems including all peripheral equipment, plus the company‘s swift support, short communication channels and solution-oriented work,” as Benedikt Niglis explains.

Benedikt Niglis, head of project (left), and Plant Manager Mario von der Heyde are more than proud of their complex turnkey system

Fig. 1. A Multilift V picks them up, inserts them into the ejector side of the mold and removes the finished parts 

Fig. 2. A six-axis robot feeds the molded parts to the camera inspection (rear area) and sorting and deposits the good parts (front area)

Fig. 3. The transfer points of the six-axis robots, e.g. on the ultrasonic welding system, can also be approached manually during set-up 

Andreas Armbruster is head of the Automation & Turnkey Solutions department at Arburg GmbH + Co KG, Lossburg, Germany.