In times of politically prescribed contact restrictions, what does the future hold for trade shows or other face-to-face events?

The plastics sector is not the only one challenged by this question but, as a capital goods industry, it is particularly hard hit. In the attempt to offer life support for major events, a limited number of options are available. The shows can be postponed to summer, as Arburg has done with its Technology Days, the VDI with its PIAE automotive congress or Nuremberg Messe with its Toy Fair for 2021– in the hope that seasonal factors will have checked the spread of infection by then. Or a strict hygiene concept can be imposed, which reconciles infection protection with the need for information by all the participants, and minimizes personal proximity between exhibitors and visitors.

The fact that this tightrope walk is possible was demonstrated in September by Caravan Salon in Düsseldorf, Germany, with over 100,000 visitors over ten days. The catalog of measures, which applies to organizers and stand builders, just as much as to exhibitors and visitors, includes the following: routing in open areas, distance marking at entrances and in front of booths, video monitoring of visitor streams, open-top booths, tables with clear partitions, powerful, constant air-exchange systems, obligatory mouth-and-nose covering (except at seats). The number of visitors per day is limited. Visitors must acquire E-tickets in advance and may only enter booths after the tickets are scanned. On the positive side, this could even make for a more relaxed, less hectic trade-show atmosphere.

The alternative is digital shoes, as have already been organized by individual companies as well as commercial suppliers. Despite the specific advantages of this genre, it has still not achieved the charm of a face-to-face trade show: the technical exchange between exhibitors and customers, as well as direct feedback from the users at the exhibit, spontaneous sales closures and personal reunions – all this should make the greater commitment worthwhile. Even though it will probably take even longer before we can enjoy the reward of booth parties once again.

Editorial_Doriat

Doriat, Clemens, Dr.

The Advantages of a Network for Global Qualification for Injection Molding

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. This is where the global, high-performance infrastructure of Barnes Molding Solutions enters the picture. The slogan here is “globally qualified local manufacturing.”

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 so-called “Global Hybrid Qualification” offered by Molding Solutions, a strategic business unit within Barnes Group (see Box p. 8) involves technology transfer based on global manufacturing capability, for which all units are tailored and harmonized for qualification of customer molds (Fig. 1). The activities involved in the process were further extended and refined during the pandemic in 2020. Norbert Scheid (Fig. 2), President of Barnes Molding Solutions, stated, “The key focus is to stay in close contact with customers all across the globe. The goal is the highest process reliability and availability of molds, regardless of where the customer manufactures.” The concept is related to all high-performance mold systems within Barnes Molding Solutions, including customer-specific hot runner systems, control technology, and process control.

The Strategic Approach of Standardized Quality Guidelines

Global Hybrid Qualification is based on two underlying principles. On one hand, customers can receive faster and more qualified support if an entire global network is utilized for the project. On the other hand, many customers are globally positioned and want to use production molds at different locations, according to defined quality standards. “The toolmaking industry must meet global demand with global solutions,” said Norbert Scheid. “Barnes Group supports this conceptual approach of global customer proximity through group-wide technology transfer.”

The most important criteria for global cooperation between Barnes Molding Solutions’ companies in Europe, the USA, and Asia are standardized quality guidelines related to CAD/CAM processes, our fleet of machine tools, and qualification. The qualification process can be carried out according to customer specifications or according to our uniquely-developed Barnes Molding Solutions benchmark. The “Molding Solutions Qualification Standard” was developed following strict scientific molding criteria.

Molds can be built in the Barnes Molding Solutions plant in China and prepared for sampling and qualification. In Suzhou, a pre-qualification routine – the FOT process (First off Tool) – is initially carried out. These molds are then subject to final qualification testing at group network locations in Europe or the USA. During the current pandemic, however, the model for developing and manufacturing molds in Europe (Germany and Switzerland) and finally qualifying them in the USA is also becoming increasingly important.

Tech Centers Bring together Qualification Expertise

Each tech center at the respective locations plays a key role. The four qualification locations in China, Germany, and the USA employ experienced process engineers and high-performance machinery. A total of 37 injection molding machines with clamping force ranging from 700 kN to 5000 kN, including machines for multicomponent and cube molds are available. Beginning in 2021, an additional injection molding machine for the automotive sector with 27,000 kN of clamping force and an injection molding machine featuring high-speed automation will go into production.

For sensitive customer development, production cells can be installed at all locations, with the complete handling process restricted to closed-off areas with separate office units. The extensive calculating technology used for assessing quality parts includes measuring machines for optical and tactile testing, thermal imaging, hydrological measurement, high-speed camera systems, and flow rate meters. After completing the “SAT ready” qualification (ready for site acceptance test), customers receive complete documentation and optimal process parameters, which allows them to begin with site acceptance testing and start production promptly.

The local application engineers then accompany the physical start-up of production. Nobert Scheid stated, “A smooth start-up of production is essential for the processor to prepare for contract manufacturing with defined delivery quantities and times. With our global toolmaking resources in engineering, project management, and lifecycle services, we ensure that our customers can carry on their operations.”

Due to global travel restrictions, the method was expanded to include “Online Mold Qualification” (Fig. 3). DOE (Design of Experiments) and FAT (Factory Acceptance Test) can occur using high-resolution camera technology, without the customer having to travel.

A Holistic Technology Approach and One-Stop Specialist

The basis for economic high-end mold concepts is the elaborate interplay between the mold, hot runner system, temperature control, and process control as a comprehensive system. Process control is becoming increasingly important in this regard. “Today, molds are intelligent process units and include automated sensors for keeping a process stable,” said Norbert Scheid. “Barnes Molding Solutions combines all components into a single high-performance production system. The customer benefits from not only a mold but also a reliable, overall solution. The low total cost of ownership this approach facilitates adds up to the highest level of customer satisfaction.”

Tool qualification in the test center in Bahlingen, Germany. After that, the tool is ready for the “site acceptance test”, i . e. for the acceptance on site directly at the customer

Fig. 1. “Seal of Quality” stands for global quality standards of Barnes Molding Solutions

Fig. 2. Norbert Scheid, President of Barnes Molding Solutions 

Fig. 3. The “Online Mold Qualification” is transmitted from the test center by a high-resolution camera without the customer having to travel

Name - Hauptartikel

Guido Radig is the owner of the Provvido editorial office; <a href="mailto:radig@provvido.de">radig@provvido.de</a>

Barnes Group Inc. is a global company whose products and services are used in many different applications and end markets, including aerospace, transportation, manufacturing, automation, healthcare and packaging. Barnes Molding Solutions Group is a strategic business unit within Barnes Group, which includes renowned brands in the areas of mold making, hot runner technology and temperature and process control. Synventive, Thermoplay, Männer, Foboha, Priamus and Gammaflux deliver a comprehensive portfolio of solutions to meet the demanding requirements of global customers in the injection molding industry (figure: © Männer).

The global network of Barnes Molding Solutions includes production sites in Germany, Switzerland, Italy, China and the USA as well as four qualification sites in Bahlingen, Haslach, both Germany, Suzhou, China, and Lawrenceville, USA. <a href="http://www.BGInc.com">www.BGInc.com</a>

Guido Radig is the owner of the Provvido editorial office; radig@provvido.de

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Medical Applications of Additive Manufacturing

Status and Perspectives for Human Medicine

Anyone who introduced additive manufacturing (AM) in a company 15 years ago was a visionary. Anyone who did not do so ten years ago fell behind the early adopters. Anyone who still is not using additive manufacturing today is losing their edge over the competition. What this technology is considered capable of today and how it can be applied in many areas of application is shown (representative) by this expert’s view of medical technology.

What AM technology is considered capable of today and how it can be applied in many areas of application is shown (representative) by this expert’s view of medical technology.

Additive manufacturing (AM) is bringing about increasingly disruptive changes in traditional manufacturing strategies. Often classic procedures such as casting or milling are to be replaced. The benefits of a procedure not bound to a specific form, such as geometric freedom, re-engineering, and resource conservation, are complemented by great economic advantages and excellent availability.

But the essential merits are not just the copying of conventional parts but rather the new designs and bionic design approaches. Time-to-market as well as quick availability and idle time reduction also come into play. In light of the debate about long supply chains as a side effect of globalization, AM is also a viable approach for local production. Local production also means that value creation, product development, and product manufacturing will take place closer to the customers. Reducing logistic overhead contributes to achieving climate goals.

Classic material groups include metal, ceramics, and plastics. For the metals and the LaserCusing procedure, a powder bed-based metal laser melting process developed by me (market share approx. 80 % of all metal AM systems worldwide), very early adoption for medical applications was possible because we were always able to use certified original materials in powder form. A similar approach also works for ceramics-based solutions. The process is a little more complicated with polymers due to the variety and material behavior of that group. That is why metal applications have a head start of about five to ten years.

When we now shed some light on the medical industry, we will see many isolated application clusters: hip, joint, or spinal implants, cranial or dental prostheses in dental technology. Medical devices, laboratory equipment, or components used in high-tech medicine are added to the mix (Fig. 1); currently, the operative word would be valves for reanimation and ventilation devices. Even veterinary medicine knows a range of examples for 3D printed implants applications by now.

Market Development of 3D Printing Providers and Users

 As reported by the Wohlers Report 2020, the total value of additive manufacturing products and services was estimated at USD 11.9 bn with medical applications representing an estimated about USD 1.7 bn. The total value of AM machines, materials, software, and services for medical applications is projected to reach USD 2.2 bn by 2024. According to Wohlers Report, with such incredible growth, keeping up with developments can be challenging.

The projected global market size estimated by SmarTech Analysis company is approx. USD 55 bn in 2029. More conservative analysts such as 3D Hubs project an expected annual growth rate between 18 and 27 %. But even that outshines many other industries by far. The British market analytics company Context predicts double-digit growth rates for 3D metal printers (Table 1) as well for polymer printers (Table 2) for the coming years. Industrial mass and mid-scale serial production, however, account for the highest sales increase in the field of additive manufacturing. This includes only part of medical technology.

With regard to the global market, EY Research reports that in 2019 722 AM companies hailed from Europe, 421 from the Americas, and 168 from Asia. AM providers in the industry, however, are currently in a consolidation phase. The enormous growth of the past ten years in particular, its numerous innovation pushes, and the consolidation of prices are taking effect. While major players may feel a stronger effect, small start-up companies are still pushing into a dynamic market with creative solutions, a market that is still far from saturation or fights for survival.

For users, on the other hand, things are still going extremely well. That is true for the medical industry as well as others. But it also applies to the numerous 3D printing service providers who guide numerous industries into the world of 3D printing with their AM expertise and manufacturing capacities. The possibilities of improving existing products with AM are just too tempting. Buzzwords include bionic design, lightweight construction, patient-specific components, the one-shot approach drastically reducing the number of components in an assembly group without any assembly required, decentralized manufacturing, and rapid availability.

Example Titanium: Implant for  an Acetabulum

In light of the boomer demographics in the West, orthopaedic implants for the human musculoskeletal system play an increasingly important role. Applications for the hip, knee, and spine are considered a relevant emerging market in medical technology. Stryker from Cork, Ireland, therefore developed a new 3D titanium acetabular system (Fig. 2) using electron beam melting (EBM) technology. The system received clearance from the US Food and Drug Administration in 2016. Stryker calls this product Trident II Acetabular System and emphasizes that it is a cementless solution, which massively improves its longevity in the body.

The 3D printing process allows for highly complex geometries which cannot be produced using conventional means. The complete implant has the durable mechanical properties of kinematics consisting of a titanium acetabular system, a ball head and a shell-shaped insert made of metal, ceramic, polyethylene, or an aluminum-ceramic composite, depending on compatibility and load, and a locking mechanism.  Of course, the providers of such 3D solutions are manifold. For the sake of proportion, here are also B. Braun, Surgival, SurgTech, ImplanTech, Imeco, Medacta, Link, or Rentec.

Example Polyamide: Venturi Valves  for Reanimation Devices

Back in March 2020, the EU responded to the SARS-CoV-2 pandemic by reaching out to the European AM industry. The idea was to use 3D-printing strategies, among others, to tackle the lack of protective equipment, such as N95 respirators, masks, face shields, or gowns as well as reanimation and ventilation devices in healthcare and the strong dependence on global supply chains. Major providers such as Draeger in Lübeck, Germany, but also many other plant and machinery installers and processors from a variety of industries heeded the call for help. Many companies had never manufactured products like these before.

Venturi valves for reanimation and ventilation devices are a good example (Fig. 3). The challenge here is to 3D-print a conventionally manufactured expendable part within a narrow time frame. That is what happened at the hospital in Brescia, Italy: the Milan-based company Fab Lab set up a polymer 3D printer in the hospital. The hitherto used valves were scanned, and new valves were printed, so the reanimation devices never stopped running. Later, Lonati Spa took over serial production using the polymer laser powder bed melting process in order to print the polyamide parts and supply Italian hospitals.

This is known in our industry as “spare parts on demand”: an essential element whenever a solution requiring a specific form is no longer available or takes too long to procure. We must also not forget to mention re-engineering in this context. If you redesign a spare part on top of everything else, an assembly part with many components may be turned onto a 3D-printed component with no assembly required in one shot.

Protective Face Shields for Nose and Mouth for Clinics

Protective equipment for healthcare professionals was a major global challenge when the pandemic broke out. Firstly, there were only emergency stocks lasting, and secondly, a lot of it was not produced in the European area. Supply chains and delivery times were too long. Prices skyrocketed unrealistically, and the quality was often dubious. If more healthcare professionals had been unable to work, the crisis could have turned into a catastrophe the way we have seen it happen in some other countries.

In this uncertain situation the emergency room of the Bamberg clinic in German asked whether there was a 3D printing solution for face shields. Basically, this is a very simple design consisting of a headband and a sheet of acrylic glass. It was not possible to recreate any certified models, but to produce makeshift equipment consisting of a face shield, protective gown, and respirator mask. And another thing was absolutely clear: this can only work in a proper network, because 3D printing can only ever be part of the solution and not the solution itself.

In this case, the network was the Lichtenfels Center of Next Generation Digital Technologies (Forschungs- und Anwendungszentrum für digitale Zukunftstechnologien, FADZ) currently under development, which brings together numerous companies in the region. Innocept, a Neuses-based company in Germany, developed a new type of respirator mask. The idea was to design a reusable respirator mask that was comfortable to wear, consisting of two soft polymer half-shells between which various filters could be inserted (Fig. 4). The benefits: the respirator filter does not sit directly on the face, making it much easier to breathe compared to makeshift fabric masks. Moreover, the large batch production of the respirator mask allows for favorable manufacturer’s prices. It is environmentally friendly because not the whole mask must be disposed.

To speed up the development process, five prototypes were produced overnight using the multi-jet fusion HP technology at the company Hofmann – Ihr Möglichmacher in Lichtenfels, Germany. Two and half weeks later, the product reached maturity. The patent was filed by Innocept. But there is another essential advantage to digital processes: STL printing files can be used as a common basis on many printers regardless of the manufacturer.

State of the Art Using the Example  of Cranial Implants

Artificial intelligence, digitalization, and automation are the pillars of the Industry 4.0 strategy. But they also inspire additive manufacturing. They will also shape the future of 3D printing as well as accelerate, innovate, and help spread it more broadly. This is only of marginal importance in medical technology, where solutions are often patient-specific. But there is still enormous leeway for a digital product. For instance, an operating surgeon can have a perfectly fitting cranial implant custom-made based on the X-ray images and their conversion into STL files (Fig. 5).

A defined porous surface makes sure that the implant is optimally accepted into the human tissue structure. But what really stops the show for seasoned medical practitioners is the design at the points where the implant meets the cranium. Thanks to that design, the component can be implanted faster and the surgical risk reduced. Quicker healing is a benefit for the patient, but so is increased quality of life. Both is a major mission of medical AM technology.

AM plants and machinery make full use of the potential of design, digital process chains, and the synergy of hardware and software. With regard to hardware, installation spaces and construction rates (assembly speed) used to play a bigger role. Currently, the required installation space in powder bed metal printing ranges between up to approx. 800 cm3. Standard installation spaces are 187 cm3 or 125 cm3 in multi-laser environments. These installation space dimensions are absolutely sufficient for any medical application nowadays. Assembly speed, too, has risen impressively due to the use of multi-laser systems. Construction rates today are up to 50 cm3/h with several 1000 W lasers.

The binder jetting technology has the potential to increase these rates in the future. That technology, developed by the Massachusetts Institute of Technology (MIT), will become increasingly relevant for simple applications with certain tolerances. In binder jet 3D printing, also known as “powder bed and inkjet”, the parts are built up layer by layer as “green bodies”. 3D data serve to calculate the geometry of every individual cross-section or layer. During 3D printing, a bed of powder or granulate is spread on a height-adjustable tabletop and then a binder is deposited to glue the parts together in the places that form part of the component.

The developments of the past ten years also led to a large increase in batch sizes. Quality assurance and automation are becoming more and more important. Quality assurance is one of the main tasks of the software, though not its only task. The software controls the build-up of a 3D-printed part. It controls the data preparation of the part and design-related tasks and it suggests an exposure strategy and parameter choices, also for the surface or density of the part. The software optimizes the orientation of the part in the installation space as well as the necessary supporting structures.

For quality assurance purposes, it also facilitates thermal behavior simulations (thermal simulation) and warpage simulations (mechanical simulation) based on a part’s density or strength. Last but not least, the software provides for a “digital twin”. The recorded optimized process parameters of the part can be saved one-to-one. This means maximum reproducibility, which only a digital part can provide.

Additive Manufacturing as a Holistic Manufacturing Strategy

Automation and the digital supply chain round off the development. Automation means the elimination of as many disturbance values as possible, to make the process safe in a protective gas atmosphere, and to design it fast and automated. It ranges from the preparation in containers and the actual setting up of the 3D printing machine to the automated post-processing such as removal of supporting structures, thermal aftertreatment, or surface processing. Maximum automation means that the whole process, from powder to the finished part, is handled without any manual activity.

The digital process chain, since its inception a challenge but also a necessity for plant and machinery installers to fully tap into the potential of AM, has been extended by now. One of its core points is the direct yield of digital STL files. Nowadays scanners can be used to capture the files directly. This can be done at the patient bedside, but also for conventional parts which are now to be produced using AM. But the digital process chain also happens in another dimension. The operative word here is modern AM plants with continuous digital process chains for production and process control (Fig. 6). This modern type requires data flow in material staging and preparation, parts production, post-processing, and intra-plant logistics, including even autonomous transport systems (automated guided vehicle systems).

Step by step, this technology will become more effective and efficient, even though the development stages are now somewhat more moderate than ten or twenty years ago. We are certainly going to see new bionic products, new designs, new materials, more sustainable products, and a broadening of applications.

Humans are now starting to join technology in the spotlight as a designing factor. While many companies are pioneers, the mainstream remains guarded: in 2019, 71 % of companies stated that a lack of expert knowledge was the greatest factor against 3D printing when it came to choosing alternative methods of manufacturing. But in contradiction, 79 % of companies stated that the number of parts manufactured by 3D printing in the next three to five years would at least double (source: Jabil survey 2019). In effect, this contradiction means that we may not know how it works, but we do know that it is becoming more important.

Companies are realizing that something is happening, but they are still reluctant to act. There must be a plus in “digital knowledge” in the future in order to shape this transformation in more concrete terms. Training and development of the “Generation 3D Printing” will be the key to the future. A training and development will give everyone anywhere in the world the advantage of site, because AM is a key way to develop and build products locally. I am also saying this in light of the debate about long supply chains all the way to China. AM permits us to manufacture locally, close to demand. There is no need for long transport routes or dependencies. Digital AM plants around the world have similar cost structures.

So we need local AM centers, “digital hot spots”. For this to happen, we must provide the technology with developers, draughtspeople, designers, and operators who understand 3D printing and are able to use it. That is the only way for us to translate traditional manufacturing strategies into the new possibilities offered by 3D printing, and to fully utilize future innovation opportunities. 3D will become a competitive factor for many companies and industries.

I do not want to end my outlook on the future of AM without mentioning the 3D consumer market. Just like for any other hardware, there will always be a market for industrial 3D printers and consumer 3D printers. The British market analytics company Context states a market volume ratio of 70 : 30. There are real quantum leaps in the market here: a state-of-the-art consumer 3D printer costs around 1000 EUR these days. I dare say that around 15 years ago an industrial 3D printer of similar parts quality would have cost between 100,000 and 200,000 EUR. This means that 3D printing is now spreading horizontally instead of vertically.

A home 3D printer – the HP multi jet fusion technology currently being the most popular – will be as much of a staple in the future as an office laser printer. It is therefore conceivable, based on geometry licenses, for numerous practical products to be manufactured at home by “people like us”. That outlook is none too bad, I believe, considering that during a pandemic such as SARS-CoV-2 you are longing to print your own protective visors or masks, without leaving the house. Using data found online.

To enhance the mobility of the spine, the upper and lower shell of this disc prosthesis are connected with an elastic double spring made of titanium. The core also contains a cushioning silicone filling. The prosthesis can be manufactured according to the patient’s anatomy using the LaserCusing process 

Table 1. Top 5 providers of metal printing (systems worth 20,000+ USD)

Table 2. Top 5 providers of polymer printing (systems worth 20,000+ USD)

Fig. 1. Several parts for the automated suturing device for heart surgery are made simultaneously on a building board

Fig. 2. 3D-printed titanium acetabular system

Fig. 3. 3D-printed polyamide Venturi valves for ventilators

Fig. 4. Reusable respirator mask, the filter elements are inserted between two soft plastic half shells

Fig. 5. High precision fit: additive manufactured craniofacial, patient-specific implant

Fig. 6. Tomorrow’s factory requires a data flow from material supply (left) through component production to post-processing (right), which also includes the operation of driverless transport systems © GE Additive / Concept Laser

Frank Carsten Herzog is founder and Managing Partner of Concept Laser GmbH, Lichtenfels, Germany, and with over 300 patent applications is regarded as one of the pioneers of industrial 3D metal printing as we know it today. As Managing Director of the HZG Group, Coburg, Germany, he supports start-ups, particularly in the field of digital future technologies; <a href="mailto:info@hzg-group.org">info@hzg-group.org</a>

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Expanded Polypropylene from Maritime Plastic Waste

A large part of the plastic waste in the sea comes from the maritime industry. The Danish company Plastix recycles old fishing nets and ropes. The granules produced are used by JSP International, among others, to manufacture expanded polypropylene (EPP). This results in a 7 % reduction in CO2 emissions compared to virgin material. In order to obtain the same properties as virgin material, the recyclates must meet strict requirements. This requires a precise analysis of the waste in the recycling process and strict quality control.

The Danish company Plastix recycles old fishing nets and ropes. The granules produced are used by JSP International, among others, to manufacture expanded polypropylene (EPP).

The fight against climate change and mismanagement in waste management are high on the global political agenda. Since the demand for plastics continues to grow in view of their advantages in many areas of application, plastic waste plays a major role in this.

However, the processing of this waste has not kept pace with the growing demand. Since 1950, some 8.3 billion t of plastics has been produced worldwide. Half of this in the last 13 years alone [1]. This corresponds to approx. 400 million t of CO2 emissions per year [2].

Plastic waste is mainly disposed of by landfill and incineration. Both types have significant negative impacts on climate, wildlife and human health. The establishment of a functioning closed-loop economy and the recycling of plastic waste into high-quality, reprocessed raw materials have therefore become global megatrends. The governments of various countries and international organizations such as the EU and the United Nations are addressing the waste problem, for example, through political and organizational commitments aimed at greater climate protection and responsible consumption of raw materials. Both have been incorporated into the United Nations’ goals for sustainable development [3].

In the maritime industry, the aim is to extend the useful life of plastics through reuse and recycling and to establish a closed loop economy for the plastics used. Millions of tons of plastics are already in the world’s oceans. According to UNO and WWF, 15 t are added every minute. 11 % of this plastic waste comes from the maritime industry in the form of fishing nets and trawls, ropes and boxes [3]. It is therefore obvious that the maritime industry has an important role to play in preventing further pollution of the oceans.

This is also relevant for companies from an economic perspective. Due to the increasing Extended Producer Responsibility (EPR), in which producers are financially responsible for the waste management and recycling of their end-of-life products, companies have to deal with this issue more intensively [4]. Recently, several legislative initiatives have been introduced targeting the maritime industry, in particular a comprehensive European Union EPR, which will come into force in 2024.

The increased focus on effective waste management, EPR regulations and stricter legislation has significantly increased the availability of recoverable waste and recyclates and has led to increased cooperation between recycling companies and plastics producers. One such cooperation exists between the Danish recycler Plastix, Lemvig, and JSP International, Estrées-Saint-Denis, France. Among other things, Plastix recycles fishing nets and ropes that would otherwise end up in landfills or in the sea. The company was one of the first 13 companies in the world to participate in the United Nations Accelerator Program for Sustainable Development goals.

Plastix purchases its plastic waste from ports, netmakers and plastic waste disposal companies worldwide. The in-house laboratory analyses, evaluates and records the recyclability of all incoming input waste streams based on their physical and chemical properties. Plastix currently has over 900 different types of ropes and nets registered in its extensive database (Fig. 1). In the mechanical recycling process used, the input raw material strongly influences the consistency of the output material. Therefore, the company attaches great importance to the quality and homogeneity of the nets and ropes entering the recycling process.

Based on their physical, chemical and visual properties, the incoming nets and ropes are roughly sorted by material type and color and finely fractionated upon arrival at the factory. Non-recyclable materials are removed in the process. Sorting, fractionating and homogenizing the input material can be a labor-intensive step, as recyclability is currently not a major concern for either the manufacturers or the users of fishing gear. Plastix fishing gear recycling technology has been developed by combining tailor-made processing with adapted standard equipment to convert separated material into quality granulate for thermoplastic processing (Fig. 2).

After sorting and fractionating, the nets and ropes are shredded, washed, separated and dried. Finally, Plastix compounds and extrudes the processed input into new plastic granulate with constant and quality controlled physical, chemical and mechanical properties. All recyclates are analyzed, quality controlled, registered in the Plastix database and their properties are described in a specific data sheet (Fig. 3). This is a prerequisite for guaranteeing high quality recycled plastics. Plastix is certified for the recycling of used fishing nets and ropes from the maritime industry according to the ISO9001:2015 and ISO14.001:2015 standards for quality and environmental management.

The “green” plastic granules produced serve as raw material for a wide range of applications throughout the plastics industry. For example, OceanIX, a recycled product called rHDPE (recycled high density polyethylene) or rPPC (recycled polypropylene copolymer), is already being used for applications such as cell phone covers, designer outdoor furniture and kayaks. According to the company’s product life cycle analysis (LCA), 1000 kg of OceanIX will avoid up to 1650 kg of CO2 emissions if used instead of virgin material.

JSP and Plastix joined forces in 2018 under the leadership of a Scandinavian initiative to investigate the possible use of recyclates from maritime industry waste for expanded polypropylene (EPP). The investigations led to the development of compatible grades, suitable process parameters for processing and analyses for quality assurance. With Arpro 35 Ocean a corresponding EPP was presented in March 2020. Arpro 35 Ocean is the first EPP with 15 % recycled content from maritime industrial waste and has a 7 % reduced CO2 footprint compared to virgin material.

JSP’s stringent recycled material requirements are key to ensuring material and processing properties areas close as possible to those of virgin material. Recent trials with different recycled material contents have shown that 15 % is the optimum percentage. The addition of more than 15 % recycled content from marine industrial waste slows down the extrusion process, thereby increasing production costs. This is due to the extended melting temperature range of the recyclate due to the different material properties of the processed fishing gear and ropes. A recycled content of 15 % currently represents the optimal ratio between recycled and virgin material to ensure certified material properties guaranteed by the manufacturer. The particle foam thus also meets the requirements for technical lightweight construction applications.

In the development of Arpro 35 Ocean, the focus was on meeting the technical requirements and conformity with the mechanical and thermal properties of virgin material. This is particularly important when used for technical, dimensionally accurate molded parts to ensure function and accuracy of fit. The particle foam is already being tested by various manufacturers and used in their products. Suppliers to the cargo bicycle manufacturer Urban Arrow, Amsterdam, Netherlands, used it to make a transport box for cargo bikes. The foamed Shorty EPP box produced for a feasibility study (Fig. 4) is made completely from Arpro 35 Ocean.

Other companies use EPP in commercially available consumer products, such as Juuce, Munich, Germany. The “stuul” produced by this company consists of two identical step stools which can be inserted into each other. This two-part design saves space in the bathroom and is very unobtrusive. The stuul was awarded the Universal Design Consumer Award 2019, the Good Design Award 2019 and the IDA Design Award 2019 [5]. Turkish company Atermit is bringing Arpro 35 Ocean back into the water in the form of a buoyancy aid for athletes [6].

The Finnish company Artekno from Kangasala also uses the particle foam for standard 6.2 and 15 liter thermo boxes. They are lightweight, mechanically resistant and heat-insulating. Such sustainable products are in demand in the currently booming food delivery market [7].

1 Geyer, R., Jambeck, J. and Law, K., 2017. Production, use, and fate of all plastics ever made. Science Advances, 3(7), p.e1700782.

2 <a href="https://www.europarl.europa.eu/news/en/headlines/society/20181212STO21610/plastic-waste-and-recycling-in-the-eu-facts-and-figures" target="_blank">https://www.europarl.europa.eu/news/en/headlines/society/20181212STO21610/plastic-waste-and-recycling-in-the-eu-facts-and-figures</a>

3 <a href="https://sdgs.un.org/goals" target="_blank">https://sdgs.un.org/goals</a>

4 <a href="https://ec.europa.eu/environment/archives/waste/eu_guidance/pdf/report.pdf" target="_blank">https://ec.europa.eu/environment/archives/waste/eu_guidance/pdf/report.pdf</a>

5 <a href="https://stuul.com/collections/ocean/products/stuul-ocean" target="_blank">https://stuul.com/collections/ocean/products/stuul-ocean</a>

6 <a href="https://actifoamsports.com/?lang=en" target="_blank">https://actifoamsports.com/?lang=en</a>

7 <a href="https://www.artekno.fi/en/news/artekno-ocean-cleaner-oceans" target="_blank">https://www.artekno.fi/en/news/artekno-ocean-cleaner-oceans</a>

Fig. 1. Over 900 different types of nets and ropes are stored in the Plastix database. The “Wall of Fame” of the company shows an extract

Fig. 2. Mechanical recycling turns the maritime waste back into high-quality plastic granulate

Fig. 3. Before delivery, the recyclates are analyzed and subjected to quality control

Fig. 4. Feasibility study for the Urban Arrow Shorty cargo bicycle: the transport container was made entirely from Arpro 35 Ocean particle foam

11 % of the plastic waste in the sea comes from the maritime industry. For the recycling of old fishing nets and ropes, accurate sorting is very important

JSP - Hauptartikel

Hans Axel Kristensen is CEO and Co-Founder of Plastix; <a href="mailto:fenella@plastixglobal.com">fenella@plastixglobal.com</a>

Jens Grunwald works as Sustainability Product Manager at JSP EMEA; <a href="mailto:jens.grunwald@jsp.com">jens.grunwald@jsp.com</a>

Helge Lüsebrink is Director Sales & Marketing at JSP EMEA; <a href="mailto:helge.luesebrink@jsp.com">helge.luesebrink@jsp.com</a>

Schaumstoffe und Vorprodukte

Kunststoff Werkstoffe

Schaumstoffe

Kunststoff-Aufbereitung

Recycling

Umweltmanagement

Standardkunststoffe

Thermoplaste

Polypropylen-Compound

Polypropylen

Kunststoff

Bauwesen

Baustoffe

Kunststoff-Recycling

Kunststoff-Rezyklat

Method for the Simultaneous Extrusion of Window Profiles with a Foam Core

Foamed polystyrene in window profiles and façade elements can improve their thermal insulation and therefore their environmental efficiency. Simultaneous extrusion of polyvinyl chloride profiles with a PS foam core is challenging due to the different processing conditions and has not been performed before. A trial plant for researching this process has now been set up at the SKZ.

Simultaneous extrusion of polyvinyl chloride profiles with a PS foam core is challenging due to the different processing conditions and has not been performed before. A trial plant for researching this process has now been set up at the SKZ.

The German energy saving regulation (EnEV) of 2014 has placed extra emphasis on the minimization of heat loss and CO2 emissions in the construction sector [1]. Large savings in energy consumption are possible due to good thermal insulation of the building. This places particular importance on the windows. This is where the energy loss, at 47 %, is greatest in a conventional house [2].

Polyvinyl chloride (PVC) façade elements and window profiles of hollow chamber design have significantly better thermal insulation properties than solid profiles. However, heat flow still takes place within the hollow chamber. This heat exchange is based on air circulation in the hollow chamber caused by different temperatures, e. g. on the building outside and in its interior. One approach to reducing the thermal conductivity of a window frame is foaming, for example with polyurethane (PU). However, profile manufacturing and foaming are usually performed in two separate steps with a high labor, assembly work and space requirement. Alternatively, foam cores, e. g. of polystyrene (PS), can be introduced into the hollow chambers of the PVC profile at great effort. The ideal situation would be a one-step process in which the profiles are directly filled with foam during extrusion.

One-Step Process for  Foam-Filled Profiles

Therefore, the German Plastics Center SKZ investigated in a research project a process for manufacturing PVC plastic profiles with physically foamed PS core in one process step. Within the project, a suitable PS foam formulation was developed and, in parallel, a trial system for process development of foam-filled profiles was set up and tested on a pilot scale. Furthermore, the joining technology was investigated and an application-based sustainability analysis performed.

For the target application of a PS foam as insulating material in a PVC window profile, first a laboratory system for foaming PS was set up (Fig. 1). It consists of a type ZSE 18 HPe co-rotating twin-screw extruder from Leistritz Extrusionstechnik GmbH, Nuremberg, Germany, a type BKG BlueFlowTM GP22/22–01 gear pump from Nordson PPS GmbH, Münster, Germany, and two type P1 cooling mixers and a type Z400 gas dosing system from Promix Solutions GmbH, Wetzlar, Germany. With this system, the foaming can be investigated for different dies, such as round-hole dies with variable diameters or film dies. In addition, the pressure level in the line can be adjusted by means of a throttle positioned before the die. That is particularly helpful during start up.

On this system, foaming tests were performed while varying the material formulation and die diameter. As material, PS 153F, melt volume rate (MVR) 7.5 cm³/ 10 min at 200 °C and 5 kg, and the PS 158N, MVR 3.3 cm³/10 min at 200 °C and 5 kg, from Ineos Styrolution, Frankfurt am Main, Germany, and combinations of these were used. As nucleation agent, talc of type Jetfine 3 C A from the Luzenac Group, Toulouse, France, was used in proportions of 1 and 10 %. To improve the thermal properties, the use of type UF1 98 C graphite from Graphit Kropfmühl GmbH, Hauzenberg, Germany, in proportions of 1 and 10 % was investigated. From the individual components, compounds were produced in a preceding step.

Foaming trials with the compounds showed that a maximum concentration of 6 % CO2 is good enough for a good foam structure and low foam density. After the CO2 injection, a pressure level above 80 bar must be maintained so that the CO2 remains securely dissolved in the melt. Temperatures of 195 °C at the gear pump, 130 °C at the first cooling mixer and 120 °C at the second cooling mixer proved optimum. The nozzle temperature must be adjusted to between 140 and 160 °C to obtain a good result regarding foam quality.

Homogeneous and Fine-Celled  Foam Structure

The extruded samples were characterized optically and by scanning electron microscopy. It was found that the foams have a closed-cell, very homogeneous and fine-celled structure (Fig. 2). In addition, the foam density was determined based on the standard EN ISO 1183–1 method A – immersion method. The studies showed that, for all material combinations, constantly extruded foams with foam densities of 0.06 g/cm3 with good cell morphology can be demonstrated.

To ascertain the insulating properties of the foam, the thermal conductivity was determined. This was calculated from the thermal conductivity, specific thermal capacity and foam density. To determine the thermal conductivity, a type LFA447 NanoFlash light flash apparatus from Netzsch Gerätebau GmbH, Selb, Germany, was used. The specific thermal conductivity was determined using dynamic differential calorimetry (DSC) with a type DSC 204 F1 Phoenix test unit, also from Netzsch Gerätebau. All the investigated samples showed a very low thermal conductivity in the range from 0.0175 to 0.0255 W/mK, where the formulations with the higher-viscosity PS 158N have slightly higher thermal conductivities. The nucleation agent used and the graphite introduced only have a slight influence on the thermal conductivity.

To investigate the extrusion of PVC profiles with foamed PS core, a tandem extrusion system was designed, set up and tested in the next step (Fig. 3). PVC processing is performed in the system on a type KMKK 40 conical counter-rotating twin-screw extruder from KraussMaffei Berstorff GmbH, Hanover, Germany. The PS is processed in the laboratory line from Figure 1. For the test system, a special extrusion die was designed and built, which combines PVC profile extrusion with PS foam extrusion (Fig. 4). The design was performed based on extensive flow simulations by Ianus Simulation GmbH, Dortmund, Germany, which could be confirmed in first test runs on the actual extruder (Fig. 5). A typical window profile formulation of PVC powder and different additives, such as thermal and light stabilizers, lubricants, acrylic impact modifiers and fillers, was used.

Both the PVC outer layer and the PS foam could be very easily extruded in the first tests in separate operations. However, since the die heated up to about 190 °C in the coextrusion process, the formation of a stable foam in the profile was hampered. The manufactured profiles were thus only partly foam-filled.

Nevertheless, the tests yielded important findings for the final process design. In the next step, the thermal separation between PS and PVC material stream was optimized and the material systems better adjusted to the temperature requirements. In addition, the manufactured foams could be used for further studies on weldability and assessment of sustainability.

The welding of foam-filled profiles is an important step for transferring the new coextrusion processes into industrial practice. To generate findings for this in the early stages, profile-foam composites were manually used with box profiles and foam extrudates and subsequently used for welding tests. A type Widos 2500 S CNC servoelectric welding machine from Wilhelm Dommer Söhne GmbH, Ditzingen, Germany, was used. The welding parameters were based on the normal parameters from the welding guideline of EPPA (European Trade Association of PVC Window System Suppliers).

It was found that the PS foam in the profile core collapses locally due to the effect of heat at the heating element, and shrinks back from the direct joint zone during heating. This is positive for subsequent applications, since it means that no PS can penetrate into the load-transmitting PVC structure. In particular, with very long-lasting construction products, such as plastic windows, possible effects on the mechanical long-term properties might not be tolerable. Furthermore, the PS foam detaches from the polytetrafluoroethylene (PTFE) coated heating element completely, so that there is no additional cleaning work.

Considerations of sustainable are mandatory, in particular for energy-saving products. In the running process, performance measurements were performed to determine the overall energy consumption and the energy consumption of the individual components. It was possible to differentiate the profile extrusion and the consumptions of the extruder, the heater and the melt pump could be differentiated during foam extrusion as partial consumptions. A total energy consumption of 0.722 kWh can be calculated for the extrusion of a meter of foamed profile (Fig. 6). A total energy consumption of 1.565 kWh can be calculated for the extrusion of a meter of foamed profile. For conventional profile extrusion without foaming under industrial conditions, the average energy consumption is about 0.2 to 0.25 kWh/kg. It is thus initially distinctly higher with foamed profiles. Under industrial conditions, i. e. with an increase of the take-off velocity and energy-efficient extruders, however, it can be assumed that specific energy consumptions can be significantly reduced.

In addition, a comparative environmental life-cycle analysis was performed for a PVC window with the standard dimensions 1.23 m x 1.48 m and an assumed useful life of 30 years. It was assumed that, due to the PS foam filling of a standard PVC profile produced by co-extrusion, a reduction of the total U-value (heat-transfer coefficient) of the window from 1.0 to 0.9 W/m²K can be obtained. The calculations showed that the energy savings in the use phase significantly exceed the greater outlay during manufacturing in the life-cycle balance. The calculation of the environmental effects of the thermal recovery of the PS foam was included in the substitution of thermal energy, and thereby also produced a reduction in the primary energy demand and greenhouse potential.

The aim of the research project was to develop a process technology for manufacturing highly thermally insulating PVC façade elements with a PS foam core in a single process step. The plant used can obtain a foam density of up to 0.06 g/cm³. The achieved thermal conductivity of the foam of 0.0215 W/mK represented a good thermal insulation class. Despite these positive results, the foam formation during direct foaming of the profile fell short of expectations. The temperature of the mandrel for guidance of the PS melt charged with blowing agent is increased too greatly by the PVC melt flowing around it. However, the constructed plant provides a good starting point for further development work at the SKZ pilot plant. In other projects, a direct temperature control of the tool mandrel can now be worked out and suitable material combinations sought.

1 <a href="https://www.enevonline.com/enev_2014_volltext/enev_2014_verkuendung_bundesgesetzblatt_21.11. 2013_leseversion.pdf; access: July 13, 2020" target="_blank">https://www.enevonline.com/enev_2014_volltext/enev_2014_verkuendung_bundesgesetzblatt_21.11. 2013_leseversion.pdf; access: July 13, 2020</a>

2 Synego Fenster Wohlfühlen beginnt mit Wärme, Broschüre, Rehau AG + Co, 2018

Fig. 1. The foaming of PS was investigated in a test system developed for this purpose 

Fig. 2. SEM micrograph of a foam sample with graphite as nucleation agent with 150x magnification: the closed-cell, highly homogeneous and fine-celled structure of the foams is good to see

Fig. 3. The tandem extrusion system permits extrusion of PVC profiles with foamed PS core 

Fig. 4. Front view of the extrusion die with frame radiator: the mold combines PVC profile extrusion with PS foam extrusion 

Fig. 5. Simulated pressure and viscosity profiles for the PVC flow channel of the die (left) and the PS flow channel (right)