Faced with a market that requires ever-greater output flexibility from ceramic manufacturers – in terms of both design and, above all, size, with ever-smaller, differentiated lots and a tendency towards reduced stocks – the ability to carry out fast mould changeovers and thus limit downtimes is now of strategic importance.
While the advent of digital decoration units provided the required flexibility on the design side, there nevertheless remained the rather complex problem of size changeovers, which involves handling an object inside the press that can weigh up to 14 tons. The aim was to reduce task completion times (which can be from over 8 hours for less sophisticated plants to 2 and a half hours where factories have a dedicated mould changeover team) drastically to no more than half an hour.
To achieve this ambitious goal it has been necessary to reduce the duration of each stage, acting on every single aspect of the procedure according to Lean Manufacturing methods: the mould, the press, the filler box and the mould handling systems.
More specifically, the mould has undergone the elimination of those components that slowed down assembly, such as fixing screws (replaced by permanently magnetic plates) and low voltage heating system (replaced by mains voltage to simplify wiring). Lifting and handling of the mould inside the press is now carried out by equipment integrated into the press itself; this greatly reduces mould-machine alignment times. The operator interface has been redesigned to simplify entry of size changeover parameters. All set-up tasks on the powder filler box have been automated to minimise the number of tasks that need to be carried out by the operator and, last but not least, the mould handling carriage has been made more agile, allowing it to be brought alongside the press with greater precision.
First presented at Tecnargilla 2010 - where visitors enjoyed the opportunity to see for themselves, at Sacmi’s experimental department, ‘live’ size changeover demonstrations that took the record-breaking time of less than 30 minutes – the device can be applied on all of the latest-generation presses.