Sustainable and lightweight:
With its many years of experience in injection moulding and its high level of automation expertise, ENGEL develops highly cost-effective production concepts for the manufacture of composite parts in large quantities.
At JEC World 2024 from 5 to 7 March in Paris, France, the machine manufacturer – headquartered in Austria – is demonstrating how high production efficiency and cost effectiveness can be combined with sustainability for both the aerospace and automotive industries.
In the ENGEL organomelt process, thermoplastic fibre composite preforms – for example thermoplastic sheets and UD tapes – are formed and functionalised in a single integrated process step. For example, reinforcing ribs or assembly elements are moulded immediately in the same mould after thermoforming using a thermoplastic from the same matrix material group as the thermoplastic sheet. This not only enables a highly efficient and fully automated production process, but also contributes to the circular economy. The consistent thermoplastic mono-material approach facilitates subsequent recycling of the parts.
At its stand in Paris, ENGEL will be demonstrating the huge potential of organomelt lightweight technology with a live machine exhibit. An ENGEL victory 660/160 injection moulding machine and an ENGEL easix articulated robot are being used to automate the production of inspection flaps for the fuselage of passenger aircraft. The production cell also includes an IR oven, which also comes from ENGEL in-house development and production.
To enable a sustainable and cost-effective process, a composite material with a recycled long-fibre core is used in combination with fabric-based cover layers. To ensure that the part can be recycled in the best possible way, care is taken to ensure that the organic sheet and injection-moulded structure are of the same type.
The thermoplastic sheets are heated in the IR oven, taken into the mould by the robot, formed in the mould and immediately overmoulded. The reinforcement ribs and a mounting clip are formed.
Heating up the thermoplastic sheet is a process step which determines the cycle time and is also relevant to quality. The thickness of the preform defines the heat-up and cool-down times. Heating up the material quickly without damaging it is important, as are short paths for transporting the heated thermoplastic sheet to the mould, to avoid the sheet cooling down again on the way to the mould and losing its malleability. This is where the tie-bar-less technology of the victory machine plays to its strengths. Barrier-free access to the mould area makes it possible to position the IR oven very close to the mould. And the robot can take the shortest path to the mould without working around interference contours. Both factors accelerate hot handling and ensure process consistency and high component quality.
In integrated ENGEL system solutions, the robot and the IR oven are integrated into the injection moulding machine’s CC300 control unit. This allows the entire process to be operated centrally using the machine display. Another advantage is that the injection moulding machine, robot and IR oven access the same database and precisely coordinate their motion sequences with one another. This reduces the cycle time in many applications.
ENGEL is showcasing the production of the inspection flaps at JEC World 2024 in cooperation with its customer FACC (Ried im Innkreis, Austria). The other project partners are Ensinger (Nufringen, Germany), Neue Materialien Fürth in Germany and Voidsy, based in Wels, Austria. The latter will be showcasing an ultra-compact system for contactless and non-destructive material and component testing using active thermography.
Great potential in all areas of mobility
In addition to the live exhibit on display, ENGEL and its Austrian partner KTM Technologies, based in Anif, Salzburg, will also be focusing on another aspect. On display will be a motorbike seat base produced using the newly developed tape sandwich process. This makes it possible to achieve a more compact part design with higher rigidity, lower weight and high cost efficiency.
“In the tape sandwich process, we work with very thin, single-layer reinforcement materials such as tapes and fabrics with a polypropylene matrix, which are inserted into both cavity halves of the injection mould without preheating before the cavity is filled with polypropylene,” as Franz Füreder, Vice President Automotive & Mobility at ENGEL’s headquarters in Schwertberg, Austria, explains. “Due to the specific mechanical properties of the sandwich structure, we can already meet the stiffness required for motorcycle seat bases with a single-layer UD-tape. This means that the tape sandwich process requires significantly less energy and simpler production cell technology than conventional fibre-reinforced plastic composite processing methods. At the same time, the production costs drop.”
In the case of this technology demonstrator, the seat bottom, with identical stiffness, the necessary installation space could be reduced by 66 percent and the weight by about 26 per-cent.
“The new sandwich structure, in which the reinforcing fibres are as far away as possible from the neutral fibre, offers maximum stiffness while minimising the number of fibres required,” says Hans Lochner, Team Leader Material and Applications at KTM Technologies. Another advantage of the sandwich structure is that standard thermoplastics can be used in components exposed to high mechanical stresses, since the part performance is driven ex-clusively by the tape structure. And that boosts cost efficiency, too.
Reducing global warming potential by up to 85 percent
The development partners have tested a variety of injection moulding materials, including bio-based and recycled PP grades in addition to conventional PP from fossil sources. The global warming potential (GWP) was determined for the various material combinations. Compared to the series production version – a seat made entirely of fossil PP – the tape sandwich technology reduces the GWP by 27 percent when also using fossil PP. This value is achieved solely by reducing the material. Using polypropylene from renewable sources reduces the GWP value by 85 percent. The component weight was reduced by 26 percent in each case. This is possible because even very thin components achieve high stiffness.
The consistent single grade plastic approach also contributes to the reduction of greenhouse gases. In combination with tapes from a PP matrix, parts can be created which can be recycled at the end of their service life.
“This new development sees us open up an affordable and sustainable solution for future mobility,” Füreder emphasises.
The first step will be to set up tape sandwich technology for use in the KTM family of motor-cycles. Besides this, ENGEL and KTM Technologies have their sights set on many other lightweight applications in a wide range of mobility disciplines. The two development partners are offering the tape sandwich process jointly, and developing solutions tailored precisely to the specific use case.
Reduced assembly overhead and labour costs
An Expert Corner focusing on automotive applications will also be dedicated to the ENGEL organomelt process. Among other things, the SPE Award-winning front-end module carrier by Lucid Motors is being showcased. Series production of the part is by ElringKlinger – headquartered in Dettingen an der Erms, Germany – and relies on the ENGEL organomelt. Depending on the vehicle type, the front-end module carrier acts as a support for the charge air cooler, the headlamp modules, the wash-water tank, the horn, the distance radar module or the air intake. It also supports the bonnet through add-on bonnet locks.
ElringKlinger has succeeded in minimising both the number of pre- and post-processing steps as well as the costs, despite a total of 37 inserts. The extremely high level of functional integration in the injection moulding process results in lower assembly overhead, which, in turn, reduces labour costs. The front-end module carrier is used in the “Air”, the first electric vehicle model by US car manufacturer Lucid Motors.