Blown and Decorated in the Mold
At their exhibition booth, Engel Austria GmbH from Schwertberg, Austria will provide much space to a highly diverse range of combined technologies. For example, injection blow molding permits the economic production of small ready-to-use containers in a single working step. Previously, there were limits to the possible number of cavities. Together with system partners Foboha and Alpla Werke Alwin Lehner, Engel has succeeded in the further development of an integral process for using multi-cavity molds, with a simultaneous and significant reduction of cycle times. Based on cube technology, an increase up to 96 cavities is possible.
At the K, and using a fully electric injection molding machine (type: Engel e-motion 740/220 T WP) with an 8-cavity cube mold built for demonstration purposes, polypropylene preforms are produced first. Simultaneously, the previously shaped preforms in the opposite mold position are moved to the second parting level by rotating the cube where they are blown. A six-axis robot integrated in the manufacturing cell removes the finished containers from the fourth position, and places them with their openings upwards on the conveyor belt. In this way, the entire handling operation is timed to the blow molding process, without increasing the cycle time. An insulating cover in position 2 prevents the preforms from cooling down.
To ensure a reproducible process (particularly in terms of wall thickness and the tight tolerances in the thread area), Engel’s intelligent assistant systems "iQ weight control" and "iQ clamp control" are used during production. For example, they can react to variations in material and mold breathing, thereby ensuring highly consistent container weights. Furthermore, the flow of tempering media through the mold is monitored and controlled.
In cooperation with the Lanxess subsidiary Bond-Laminates and the film specialist Leonhard Kurz, Engel has developed a highly integrated process for lightweight construction applications. Hereby, a continuous fiber-reinforced preform (organic sheet) is heated in an infrared oven, transformed in the injection mold, and back molded with plastic. To obtain a better surface quality, the mold is tempered dynamically. The procedure is finalized by an in-mold decoration (IMD) step, in which a transfer film with a decorative coating is passed through the parting line by a roll-to-roll process, and then back molded. While the decoration remains on the molded part, the transfer film is removed after the injection process. Consequently, the molded parts must not be decorated or lacquered in a time and cost intensive downstream procedure. Also in Düsseldorf, an Engel insert 500V/130 single will be producing a robust, appealingly decorated notebook housing with only 0.6 mm wall thickness (Fig. 3).
With in-mold graining (IMG) in the roll-to-roll method, Engel integrates a further process for modifying the surface during injection. IMG is similar to the IMD process described above, but the film is customized after injection molding and remains on the molded part. In this way, surface properties such as color, structure, and haptics are determined exclusively by the film (DecoJect). Therefore, it is also possible to use lower cost, uncolored plastics as well as foaming procedures, which on their own would not produce the required surface quality. With this process, the film is heated in the open mold by means of an infrared heater, and is then fixed and preformed in the mold. Hereby, the infrared heater is guided by a handling unit. Following the back injection and film punching, the sample part – a simulated large door cladding component in this case – is removed and automatically customized.
Hall 15, booth C58
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