MACHINERY | DIE DEVELOPMENTS


“In future, Red PCE 3.0 will be the standard version for gaskets extruded onto the main profile in the premium segment,” said the company.


Swell solution A Netherlands-based researcher has developed a simulation model that helps to reduce the problem of die swell.


When plastic is extruded through a die, it tends


Above: Encoma is using a QuickSwitch line from KraussMaffei to make various sizes of three-layer HDPE pipe


– which can damage the aluminium layer. This leads to improved productivity and quality, says Maillefer. The quick-change tooling is one of a number of


upgrade packages that Maillefer has developed for both composite and all-plastic pipes. Others include: upgrading to five-layer extrusion (for all-plastic pipes); reduced die drool (for both types); and fast head cleaning (both types).


Greiner acquisition Battenfeld-Cincinnati is the new owner of Austria- based Greiner Extrusion, a specialist in profile extrusion dies. The acquisition, finalised in December of last


year, sees private equity company Nimbus – the owner of Battenfeld-Cincinnati since 2016 – take ownership from Greiner. Nimbus believes that the combined technical capabilities and global reach of the two companies will provide “significant opportunities” in the profile extrusion market, while also improving areas such as parts manufacturing and purchasing. One recent development from Greiner Extrusion


is its Red PCE 3.0 system for post co-extrusion of window gaskets. Post co-extrusion (PCE) is traditionally applied in


the area of windows and doors where gaskets have to be extruded on or into the main profile. A number of enhancements make the new system more efficient than earlier Red PCE models. For instance, no direct contact occurs when


preheating the welding point, while the optimal production position can be easily adjusted – with- out geometrical limitations, and at a targeted heat input in the carrier profile, says the company. Compared to earlier models, Red PCE 3.0 is suitable for all standard PVC compounds and tools with its simpler configuration mode using indicator markings. Preparation of the welding points helps to reduce energy consumption.


36 PIPE & PROFILE EXTRUSION | May/June 2022


to expand due to internal stresses in the material. The problem is usually solved by trial-and-error – but it is time-consuming and can create large amounts of waste material. In her PhD thesis, Modeling and optimization of polymer extrusion, Michelle Spanjaards – a member of the Polymer Technology research group at Eindhoven University of Technology – has developed a numerical model to predict the shape of the extrudate. It allows the shape of the die to be optimised, to produce an extrudate of the correct dimensions. Spanjaards developed a transient 3D finite element model for viscoelastic fluids emerging from complex dies – and combined it with a real-time active control scheme. This solved the inverse problem of three-dimensional die design for extrudate swell. “The results obtained on extrudate swell and die


optimization have shown the potential of the numerical model developed in this thesis,” she wrote in her summary. “The numerical framework has been set up in a general manner, and can be used to investigate polymer extrusion for fluids with different rheological properties and different die shapes.”


Die simulation At last year’s Antec conference, Mahesh Gupta – president of software company Plastic Flow – co-authored a paper on simulating flow through a PVC window profile die. “The main goal in the design of a profile die is to develop a flow channel geometry that will minimise distortion after the polymer leaves the die,” he said. “This is achieved by minimising the variation in the velocity distribution at the die exit.” In this case, the shape of the profile was modi- fied during extrudate cooling by changing the shape of successive calibrator profiles. The effect of non-uniform exit velocity, cooling shrinkage and the shape of calibrator profiles on extrudate deformation was included in the simulation. Gupta, and Kim Ryckebosch of Deceuninck, fine-tuned the die design using Plastic Flow’s PolyXTrue software. The combined flow, thermal and structural analysis was used to predict extru-


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IMAGE: KRAUSSMAFFEI


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