PETnology Europe 2024_summiteer

Stretch blow moulding

High Speed – High Tech – High Value

Developing individual machines while  thinking in terms of systems. Dr. Otto Appel spoke with Jochen Hirdina, Head of Plastics Technology,  and Robert Aust, Head of Product Management, Plastics Technology,  Krones AG, Neutraubling, Germany.

Piovan April

CC: Of course, these changes also led to some weight reductions, which reduce the load at high rotational speeds.

H: Yes, but the weight of the bottom mould carrier was a further challenge for our development engineers. One disadvantage at high speeds was the stroke length of 40–50 mm, for instance. What we needed here was weight optimisation. We managed to achieve this extremely well.

CC: What do the process engineers think about the new possibilities that have opened up for you?

H: In terms of process technology, our engineers definitely see even more room for improvement. In terms of blow moulding, we have no problem achieving high performance. We are still working with the same stretch speeds and our well-known electromagnetic stretching system. We have a bigger process angle, and we are translating that into improved performance. That’s what it’s all about.

CC: With all these new mechanical developments, have you changed your entire range of stretch-blow moulding machines?

H: No, we are taking a two-pronged approach. There is something that I really want to emphasise here. While the Contiform 3 Speed is optimised for highperformance applications up to 2,000 mL, the Contiform 3 Pro can actually do everything — including heat setting and large-volume bottles, up to a gallon. However, the output of the blowing station is limited to a maximum of 2,500 b/h in this case. The Contiform 3 Speed only works with the optimised mould concept with a diameter of 125 mm. Anything that fits into that can be blown and produced for standard applications. It cannot be used for special applications, such as bottles with handles or heat-set bottles. You could look at the Contiform 3 Speed as our “worker bee” for high performance, whereas the Contiform 3 Pro provides maximum flexibility. It has more installation space and can also be used with blow moulds with external diameters of 125, 150, 160, and even 200 mm. The Contiform 3 Pro can therefore accept all of the usual blow mould formats on the market. Here the pressure compensation pad continues to play an important role, including for dealing with any differences in play. In principle, the platforms are identical. What is different is the mould carrier, and therefore the blowing station, allowing multiple blowing stations to be accommodated on the pitch circle. A: I’d like to add that in 2018, we delivered multiple aseptic blow moulding machines that also had no pressure compensation pads. This brings with it significant advantages for aseptic applications. As you saw on the way here, a new assembly hall is being built for these aseptic blow moulding machines and blocks. The number of machines, the required hall size, and the required load capacity for the crane are what made this necessary.

CC: What has changed with regard to the heating module?

H: The heating module is identical in both machine designs, Speed and Pro. When we were creating the new version, the focus was on minimising the radiation space, depending on the length of the preform. This was achieved using base reflectors that can be adjusted in height, thus allowing them to be optimally adapted to the preform length in question. The radiation space has been minimised, which reduces the radiation lost. Actually, we had discussed using mirrored reflectors—after all, such concepts do exist. However, we made a conscious decision not to take this route because we feel it is less suitable for everyday use, and more problematic in terms of cleaning. We have had great success with ceramics, which are extremely advantageous even in the long term as they lose a maximum of 2% of their reflectance over their life cycle.

CC: So the microwave heater that was unveiled at the last K trade fair is not yet ready for use?

A: We currently have machines with this technology on the market. As it is stateof-the-art, it will not be included in our plants for the time being. Microwave heating works well, but, compared to IR, it is still too expensive for the moment. But I am very optimistic that we will be able to unveil a solution that is ready for serial production in a few years.

CC: Could you give us an insight into how the Contiform 3 Speed was developed?

H: Development began about two years ago with the blowing module, the heart of the system. Actually, the blowing station is something of a perennial issue for us in our development work - it keeps us busy all the time. In order to verify the new development, we carried out the initial field tests on customers’ premises relatively quickly. The systems have been in operation for one and a half years now. The actual machine development was done in 2018. Today the machine is already on the market. At the same time, we are checking all quotations to see whether the Contiform 3 Speed can be used. If it fits into the concept, there are benefits for the customer, such as achieving comparable output rates with fewer moulds. The first serial production machines will be delivered in April. We expect the Contiform 3 Speed to be a top seller.

CC: Does the Contiform 3 Speed fit into the modern block concept?

A: The Contiform 3 Speed has been designed very much as part of the block concept. This means it is perfectly adapted to the current trend. The degree of blocking at Krones is about 80%, so there are few individual machines. With the Contiform 3 Speed, we will be continuing the success story that began with the ErgoBloc L. This concept - the 250 ErgoBloc L - (is being installed at Niagara Bottling in Mexico) is what brought about the major technological boost. ErgoBloc L provides stretch blow moulding, labelling, filling and capping in a single block.
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