PETpla.net Insider 05 / 2018

BOTTLE MAKING 31 PET planet Insider Vol. 19 No. 05/18 www.petpla.net Stretch Blow Molding, part 9 - Oven section, transfer functions Machine details by Ottmar Brandau Ottmar Brandau has newly revised his book “Stretch Blow Molding”, rst published by hbmedia/ PETplanet Publisher, and now re-issued in a third edition under the Elsevier imprint. PETplanet Insider is publishing extracts from successive chapters in a series of articles. Different heating methods A completely different heating system has now been developed that uses microwave beams instead of infrared lamps (Fig. 4.5). Figure 4.5 Standard infrared emits favorable wavelengths below 1.5μm (1,500nm) only at high output rates of 3,500K whereas NIR delivers these over a larger range. Diagram courtesy of Adphos Group. Heating time is said to be around 3s, allowing the use of just 16 heat- ing mandrels for an eight-cavity blow moulding machine compared to about 160 mandrels in a conventional oven system. This signicantly reduces changeover time for a different neck nish. Preforms absorb 95% of the microwave energy with excellent pen- etration independent of their colour, making fan cooling and equalisation time a thing of the past. Microwave stations are mounted in a rotating oven system rather than a linear one making the oven section very com- pact. Another advantage is that the neck nish does not need protec- tion opening the door for improved wide-mouth container processing. A possible disadvantage is that proling the heat output is not possible. This means that the preform design has to be perfect so that an evenly heated preform yields a bottle with even wall thickness. This is an exciting step into lower energy consumption and better control over preform temperature and we will see how far it can go (Fig. 4.6). Figure 4.6: This system uses a rotary microwave oven system that drastically reduces heating time. Picture courtesy of Krones AG. product development caps & closures design high cavitation moulds multi-component moulds closure production systems after sales service competent – professional – inspiring Dr.-Walter-Zumtobel-Strasse 9 | 6850 Dornbirn | Austria | www.z-moulds.com NPE 2018 May 7th-11th meet us at booth S15070 Moulds at NPE 26mm 3-start water @ENGEL, booth W3303 @SUMITOMO DEMAG, booth W3045