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Engel present pre-series production solutions for the automobile and other sectors

News International-French

15 Nov 2016

The aim of development work is to speed up the introduction of innovative lightweight construction technology to high-volume series production. The machine manufacturer will present new pre-series production solutions for the automobile, teletronics and technical component sectors.

In partnership with Schöfer, ENGEL has developed a pre-series manufacturing cell for the manufacture of thermoplastic fibre-reinforced components using the in-situ polymerisation technology.

Producing ready-to-fit components from polymer granules in a single step is cutting-edge practice in the injection moulding field. However, such efficiency is yet to be achieved in the direct production of lightweight components from dry fabrics or NCFs. Of the processes used by industry, HP-RTM technology comes closest to the objective of making ready-to-fit parts from dry preforms in a single step. Since the in-situ polymerisation of ε-Caprolactam presents fresh opportunities in this area, it will form one key focus of the Engel presentation at the trade event. Production efficiency is enhanced thanks to the combination of in-situ polymerisation and injection moulding, while the use of ε-Caprolactam supports the trend towards greater usage of thermoplastic matrix materials.

In-situ polymerisation and injection moulding combined
In the in-situ process, polymerisation and the moulding process are combined in an injection moulding machine on the basis of dry, pre-shaped reinforcing fabrics. Since the presentation of the first prototype machine, Engel has continuously optimised the system components and developed a completely new reactive unit that can be combined with different types of Engel injection moulding machines. Engel was the first supplier on the market to melt and process the solid monomer according to need. The advantages of this are significantly reduced thermal load, and therefore higher product quality. Engel sees great potential for the automotive industry and for other applications, for example in the field of technical injection moulding.

In partnership with Schöfer (Schwertberg, Austria), Engel has developed a pre-series manufacturing cell for the manufacture of thermoplastic fibre-reinforced components. Representing the wide range of possible applications, shovels are produced on the Engel v‑duo 1560/700. The clamping unit is equipped with a sliding table fitted with two mould halves for optimal accessibility. Dry, pre-shaped reinforcing fabrics are inserted into the first cavity and infiltrated with the reactive matrix. To do this, the solid ε-Caprolactam is melted and metered in the reactive unit. Thanks to the monomer's low viscosity in the molten state, the dry fibres can be wetted particularly well. A highly resilient composite is thus formed when polymerising to polyamide 6. Since reactive processing takes place below the polymer's melting temperature, the composite semi-finished product can be transferred to the second cavity immediately after it was produced where it is functionalised by injection moulding. Reinforcing ribs and contours of short glass fibre-reinforced PA 6 are injected to achieve this. Polymerisation and injection moulding take place parallel to each other. An  Engel viper 40 double robot takes over handling the fibre preforms and finished parts as well as transferring the semi-finished products.

With its v-duo series, Engel has developed a relatively compact, energy-efficient machine specifically for fibre composite applications and multi-component processes with fibre preforms, and one which facilitates particularly cost-effective production solutions. Its vertical clamping unit can be accessed from all four sides instead of just two. When processing dimensionally unstable semi-finished fibre products in particular, it is often advantageous to work in the direction of gravity.

In the production of notebooks, tablets, smartphones and other hand-held devices, the use of innovative composite materials for housings is key to reducing weight and improving stability.
Processing of thermoplastic fabrics using extreme thin-wall technology
Another key focus of Engel’s stand will be the processing of thermoplastic, continuous fibre reinforced semi-finished parts (thermoplastic fabrics) via the injection moulding process. Engel will use components and videos in Düsseldorf to present an example from the teletronics industry. In the production of notebooks, tablets, smartphones and other hand-held devices, the use of innovative composite materials for housings is key to reducing weight and improving stability. Together with its partners Bond-Laminates (a LANXESS Group company based in Brilon, Germany) and LEONHARD KURZ (Fürth, Germany), Engel has succeeded in developing a highly efficient production cell for the manufacture of exceptionally robust housings with high quality surfaces using extreme thin-wall technology. With a wall thickness of only 0.6 mm, the demonstration part reveals completely new possibilities.

The highly automated production cell was specifically designed for the material combination of a thermoplastic, continuous fibre reinforced semi-finished part (Tepex®) and the IMD film developed and patented by Bond-Laminates and LEONHARD KURZ. The system solution incorporates three processing technologies to support the in-mould decoration of thermoplastic composite components in mass production: Engel organomelt for shaping and functionalising thermoplastic fabrics in an injection moulding process, Engel variomelt for optimising surface quality through variothermal mould temperature control and in-mould decoration (IMD) for optical and functional surface finishing directly in the injection mould. At the heart of the production cell is an Engel insert 500V/130 single injection moulding machine, an Engel easix six-axis robot and an infrared oven for heating the thermoplastic fabrics, which was also developed and built by Engel .

What makes the new method special is the fact that the continuous fibre-reinforced, semi-finished thermoplastic material is shaped, overmoulded and given a high-quality surface decoration in a single processing step. To attain a direct material bond between the thermoplastic fabric and the IMD film, Bond-Laminates and LEONHARD KURZ further developed the materials, the mould and the technology required to process them, thus paving the way for a high degree of process integration. To achieve a durable and decorated surface finish with the conventional process, composite components must be treated and painted in additional work steps after the injection moulding process. Integrated production has eliminated the need for several work steps. In the Engel system solution, both the Engel easix multi-axis robot and the IR oven are fully integrated into the CC300 control unit of the injection moulding machine. Therefore the preheating of the semi-finished products can also be centrally controlled from the IMM display. Temperatures and heating times are stored together with the data of the injection moulding process, which simplifies the documentation, evaluation and tracking of the overall process.

Engel IR ovens are characterised by very high thermal homogeneity, with the various heating zones individually defined and regulated. They are available in five sizes, up to a heating surface of 1,110 x 1,610 mm; to give an example, this will facilitate the processing of large semi-finished parts for complete door modules or front ends for the automobile industry.

ENGEL recently commissioned a second, larger v-duo machine at its Center for Lightweight Composite Technologies, which is located in St. Valentin.
Integrated system solutions for cost-effective lightweight design
State-of-the-art lightweight design, and thus sustainable mobility, would be hard to imagine without intelligent, highly-integrated processes. Compared with aerospace engineering, car manufacturing is characterised by high volumes, and thus exposed to considerably greater cost pressure. This necessitates completely new methods in the production of fibre-reinforced plastic components. The Center for Lightweight Composite Technologies established in 2012 by Engel in St. Valentin, Austria, aims to accelerate the development and market launch of this process. The Center provides an interdisciplinary platform for collaboration with customers, partner enterprises and universities. Core areas of activity include the processing of thermoplastic semi-finished parts (thermoplastic fabrics and tapes) and thermoset compression moulding materials such as SMC along with reactive technologies using thermoset and thermoplastic systems (such as HP-RTM and the in-situ polymerisation of ε-Caprolactam).

Engel is expanding the capacity of its Center for Lightweight Composite Technologies in order to widen its range of applications and technologies still further. A second (larger) Engel v-duo 1700 machine with clamping force of 17,000 kN is already in service. The machine is equipped with an injection unit, an Engel easix robot and a high pressure metering system for reactive process technology, and may be combined with the IR oven developed by Engel . It is available for both development work and customer trials at the Engel premises in St. Valentin.