PETpla.net Insider 12 / 2020

PREFORM PRODUCTION PETplanet Insider Vol. 21 No. 12/20 www.petpla.net 15 tive, hand cleaning is a complex process that requires mould components be indi- vidually removed, cleaned, rinsed, dried and replaced with the use of spray cleaners, solvents and brushes. Dry ice blasting is a non- abrasive method where the mould is cleaned directly in the press while still hot. Grain-sized carbon dioxide pel- lets are introduced into an air stream and are shot through nozzles at high speed to quickly remove residue. Both of these methods are time consuming, require skilled mainte- nance personnel and must be thor- ough to eliminate processing defects. Repeated motions could result in operator injuries, and mould parts and inserts can be damaged during the cleaning process. Running rPET amplifies manual cleaning challenges, including the need for more frequent cleaning. Fur- thermore, running different qualities of rPET can cause greater risk of outgas- sing and dust deposits in vents, which can lead to a higher risk of defective parts. Having a reliable, fast and easy method of cleaning maximises suc- cessful rPET material running. Husky’s Self-Cleaning Technology skips tra- ditional maintenance interruptions of 2-6h; its automatic process is simpli- fied to the touch of a button and lasts just a single extended machine cycle. It eliminates the need for operators to enter the machine and can be per- formed as often as needed and helps to resolve the conflict between cycle time and mould maintenance. The secret to Self-Cleaning Technology is controlled flash, using precisely controlled gaps to ensure flash does not travel beyond the target area. During a self-cleaning cycle, the vents are filled by PET flash; the overflow of PET from the preform. The flash then sticks to dust in the vents and the flashed preforms, complete with dust, are then ejected, leaving cleaned vents behind. Effective combination While Ultra Hot Runners and Self-Cleaning Technology do not com- pletely elimi- nate the need for traditional mould cleaning methods, they represent a sig- nificant evolution in mould mainte- nance and offer manufacturers added flexibility and reduced risk when running rPET – especially when used together. This addresses many of the common issues associated with mould maintenance, including minimis- ing labour and downtime, streamlin- ing the moulding process and making cleaning safer. It enables producers to be more sustainable, by supporting higher percentages of rPET to be run more efficiently. Case study An established preform manu- facturer located in the United States installed Self-Cleaning Technology on a HyPET HPP5 system. Traditionally, this customer manually cleaned vents every 50,000 cycles or on detecting defects such as top sealing surface shorts, flow lines on the thread finish, or shorts in the leading thread. As their operation runs continuously, they were sensitive to downtime. Their existing mould cleaning methods had difficulty keeping up with required maintenance activities. At a glance: Self-Cleaning Technology increases uptime and production capacity:  Automated mould vent clean- ing significantly reduces the risk of short shots  Convenience makes cleaning more likely to be performed  Cleaning can be performed more frequently and consist- ently Ultra-spring package and enhanced seal design streamlines operations by:  Eliminating dust issues and consequent downtime required for cleaning  Providing cold start protection and reducing risks of air leaks and stem blockage  Offering a superior balancing and processing window advan- tage The ergonomic and downtime concerns with dry ice cleaning caused them to explore the development of costly equipment to automate the dry ice cleaning process. After discovering and implementing Husky’s Self-Clean- ing Technology, this investigation was halted. The customer was able to reach 570,000 cycles with no require- ment for dry ice cleaning. Estimated savings in maintenance time are more than 320 h/a. www.husky.co