PETpla.net Insider 11 / 2020

MOULD MAKING PETplanet Insider Vol. 21 No. 11/20 www.petpla.net 20 Monitoring the efficiency of mould operations The smart guardian Otto Hofstetter showcased its OH Xport at the K2019 trade fair. This allows mould data to be gathered autonomously from the preform mould. In particular, it continuously gath- ers information on mould breathing as an important fea- ture of mould condition. The first machines are now being deployed. We spoke to Stefan Zatti and Markus Feldmann, Otto Hofstetter, Switzerland. PETplanet: Mr Zatti, injection moulding machines document a large number of parameters during produc- tion. This allows conclusions to be drawn about the quality of the pre- forms. Why is your new OH Xport box needed? Stefan Zatti: The idea behind it is that we measure the mould breath- ing during the cycle. This is normally around 25 .. 30 micrometer. If the value drifts away from the target, it is a sure sign that something is not right, long before the quality of the preforms drops. No machine controls record this value. If the value changes, it is high time to recondition the mould. PETplanet: Your moulds have a reputation for having the longest tool life on the market anyway. Why do you need more measurements? Stefan Zatti: Mould breathing is a crucial factor. This enables mould life- time to be increased even further and plan intervention when parameters start to develop in the wrong direction, long before preform quality is affected. Next to mould breathing, a variety of other sensors analyses the operating condi- tions. The hot runner is monitored in order to protect against leakage, and the cold half is monitored for condensation, with alarms possible via twitter. The stop reason evaluation allows tracking error causes, error times and frequency, which are important information when improv- ing plant efficiency. PETplanet: Do the machine controls not record these values as well? Stefan Zatti: To some extent, yes. However, for the cooling water flows, the machines often regard the mould as one unit. For example, and in the case of the hot runner starting to clog, the cooling water bypasses via the cold sign and the problem becomes visible only at a later state of the process. By close-look moni- toring, OH Xport monitors those mould components which are really the critical ones, and any issues which arise are detected much earlier. PETplanet: This means that the efficiency of the mould increases, as any possible causes of parameter changes can be rectified during routine down- times? Stefan Zatti: Yes, OH Xport moni- tors the efficiency of the mould opera- tion, thus measuring the overall uptime efficiency of the entire injection system. PETplanet: Why do you not inte- grate this measurement recording and log into the machine controls? Stefan Zatti: We offer a system which runs independently from all other controls and customer networks. Plug and play, so to speak. OH Xport works regardless of the machine installed. We don’t have to adjust to other systems, we do, however, offer compatibility with various centralised production control software systems. PETplanet: Are devices already being installed in the field? Stefan Zatti: Yes. A couple of sys- tems are running in Europe and Asia, with others being commissioned soon. PETplanet: Thank you very much! www.otto-hofstetter.swiss OH Xport The standalone device collects measurements of mould breath- ing, coolant parameters, hotrun- ner temperatures and downtimes from up to 10 preform moulds per machine. Data is stored and com- puted within a cloud-based data engine. A web-based Visualization Dashboard provides the evaluation results. OH Xport can be installed on site within 2-3 hours. A 72 cavity side entry mould 144 cavity working horse for 12-16 million cycles before refurbishment, now being converted into a side entry mould F.l.t.r.: Stefan Zatti and Markus Feldmann