The screw, non-return valve and barrel massively influence the melt quality and repeatability of the injection moulding process as well as the lifespan and cost-effectiveness of the injection moulding machine. The continuous advances in plasticising systems and in-house screw production are thus core competencies at Engel. The injection moulding machine manufacturer and system solution provider based in Schwertberg, Austria, is the world's largest screw manufacturer in the injection moulding industry. At K 2019 from October 16th to 23rd in Düsseldorf, Germany, Engel is presenting its extensive plasticising portfolio.
As a provider of tailor-made, integrated system solutions, Engel also adapts the plasticising unit to the specific requirements of the respective application. Accordingly, the requirements placed on plasticising units are continuing to grow. “This is driven, among other things, by the on-going substitution of traditional technical materials, which generates considerable increases in the performance of polymer materials,” reports Günther Klammer, head of the Plasticising Systems division at Engel AUSTRIA. “We ensure that even new materials can be processed even faster and to even higher quality standards despite what are in part increasing stresses on mechanical components.” The keys to this are, on the one hand, continuous investment in new machining technologies and, on the other, splitting the screw portfolio in order to offer the best possible solution for every material execution.
Engel's plasticising experts offer comprehensive consulting services for the geometric and material selection of the most suitable plasticising system, troubleshooting and process optimisation. They will also be passing on their experience to trade fair visitors during K and bringing various industry solutions with them. For example, the Universal Automotive Screw UAS, which enables very high plasticising capacities and material throughputs across a wide range of materials in the automotive industry, and the MBS (Mixing Barrier Screw), which achieves the best colouring results in the packaging industry thanks to a barrier geometry with a dynamic shear mixing head.
Engel's response to the increasing requirements of the automotive industry in particular, and the increasing use of fibre-reinforced materials, takes the form of two new screws – the PFS (Physical Foaming Screw) and the LFS (Long Glass Fibre Screw).
PFS: Improved homogeneity in foam injection
The PFS was developed specifically for structural foam moulding. In conjunction with a new material design, the new screw geometry ensures even better homogenisation of the gas-loaded melt and increases both productivity and the screw service life wherever fibre-reinforced polymers are used. A victory injection moulding machine equipped with the new PFS is producing highly decorated, three-dimensionally complex parts at Engel's stand during K 2019. The application combines MuCell structural foam moulding from Trexel with the roll-to-roll IMD process.
LFS: Gentle processing of long glass fibres
Long glass-fibre reinforced polypropylene and polyamide are used for lightweight automotive construction – above all when high impact strength, excellent impact behaviour and low weight are required. The processing challenge in injection moulding is to keep the fibre as long as possible and ensure uniform distribution of the fibres in the melt. The previous solution was a single flighted 3-zone screw with a bolt-on long glass-fibre (LGF) mixing head. With the demand for injection moulding machines for processing long glass fibre-reinforced rod granules on the rise, Engel decided to manufacture the screw and mixing head from a single piece and to further optimise the screw geometry. The newly developed LFS offers maximum plasticising consistency when processing rod granules and reduces fibre breakage. In order to ensure superior distribution of the fibre bundles in the product, the screw geometry was also optimised. Highly effective flight-welding gives the screw the required wear- and corrosion-resistance.
The LFS for processing long glass fibre-reinforced materials reliably maintains the fibre length and ensures uniform distribution of the fibres in the melt
With more than 20 different screw types for standard, high-performance and custom applications, and an equally extensive range of non-return valves, Engel offers a perfectly matched plasticising unit for any application. Another unique selling point at Engel is that screws are also available for custom applications with large diameters.
To further expand its plasticising expertise, Engel has – over the past three years – invested more than 17 million euros in innovative machine tools, heat treatment equipment and machining technologies at its St. Valentin site in Austria, where the Engel Group's competence centre for its worldwide production plants is located. For example, a new laser welding system was put into operation for the flight-welding of screws subject to particularly high mechanical stress, while the company's in-house materials laboratory was equipped with new analysis systems.