PETpla.net Insider 10 / 2020

PREFORM PRODUCTION PETplanet Insider Vol. 21 No. 10/20 www.petpla.net 24 the previous versions in every respect in terms of material throughput kg/h, homogenisation, intake behaviour, start-up behaviour (usually lower granulate temperatures at the begin- ning), AA values and IV drop. PETplanet: There are some market traders who are convinced that using shot pot will always produce specks. Old PET residues from the pot generate black spots. Stefan Kleinfeld: This might well have happened in the past. Today, designs are much improved. The piston in the shot pot is essentially lubricated by the PET, thereby forcing out any older material lying between the piston and cylinder. This ensures that only freshly plasticised matter can enter the mould. PETplanet: The screw is electri- cally driven but transferring of the melt into the shooting pot is hydraulically. How did you attach the energy-saving pin to the hydraulic system? Stefan Kleinfeld: In principle, we have stuck to our model by using a con- trolled pump and hydraulic accumulator but have become much more efficient when it comes to the detail. One issue is the reduction of the hydraulic pres- sure which is needed when transferring the melt. Another issue, for example, is that of hydraulic oil. We now use HLP46 which has the necessary viscosity level at 40 degrees. Previously, that figure was 50 degrees, which means less heating and radiation energy. The oil is also available to users worldwide. A positive side-benefit is the hydraulics and its accumulators. In the event of a power failure, the oil will continue to flow through the pump from the accu- mulators. The pump’s electrical drive is then used as a generator with the machine able to complete the cycle in a controlled manner. The new 4,000 kN Netstal PET-Line. Sideways preform removal, 1.9 s lock-to-lock and highly energy efficient, as well as the potential to use existing moulds that are characteristic of the new concept. PETplanet: You can look back on decades of experience in using injec- tion moulding machines. But the con- cept of sideways removal is a new one for you. Surely your competitors have the technology covered with patents? Stefan Kleinfeld: The first thing to say is that we have again made a thorough appraisal of the type of assembly, with cycle time and energy efficiency being key for us. The removal carriage recov- ers electrical energy during nega- tive acceleration. By not connecting the placement arm to the moving panel, we have achieved greater freedom. Of course, we have studied the patent situation in great detail. However, sideways removal has been on the market for quite a while now, so some of the patents will have already expired. Internal pre- form cooling is one example. With our extraction system, we are able to handle all industry specifications, from internal preform cooling to the four post-mould cooling stations. PETplanet: Is the user interface also new? Stefan Kleinfeld: It’s not just the user interface – the whole control system is new. Better resolution of the parameters ensures that the machine can run smooth start-up and start- down curves at high speeds. But, you’re right, the user interface is a new innovation. The emphasis here has been on how easily the unit can be operated using only four buttons. We have had excellent results using this simplified approach when dealing with medical products. System failure due to operational error has been significantly reduced. Basic machine operators can be trained within a very short period of time. Specialists, of course, have full access to all set-up programmes. PETplanet: Have you also been able to bring your partners on board? Stefan Kleinfeld: Take Piovan. Control of the PET drying process can now be done from our interface or IMDvista. Preform control by a visual inspection system is integrated directly once the preforms have been discharged. PETplanet: With all the technical advantages, it is also important for attracting new sales that your system can be housed within existing produc- tion facilities in order to undertake sideways removal. How is this going? Stefan Kleinfeld: In spite of the toggle lever, our unit is several centi- metres shorter and narrower in its size category than other suppliers. Our new Netstal PET-Line also fits into properly sized storage areas. Media connections are located in the plas- ticising area, i.e. where the user nor- mally has their supply. And as energy consumption is low, the electrical feed should also be sufficient. PETplanet: You have installed a lot of new and more expensive machinery compared to the more traditional PET plants. Are you able to offer equipment at a marketable price? Stefan Kleinfeld: I mentioned this at the outset. We have always gone down the road of having the high- est efficiency and durability. We have