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moldmakingtechnology.com 23 Cleaning in a Flash molding systems. As cycle times decrease, molds naturally require maintenance more often. As a result, the benefit of increased productivity must be weighed against a significant rise in cycle-based maintenance activities. One solution to help make the mold-cleaning process faster, easier and safer is a self-cleaning mold technology that uses controlled flash of the tool into the vents where dust and debris collect. This technology currently is only available for polyethylene terephthalate (PET or PETE) preform mold applications in beverage packaging. However, conceptually, it could be applied to a variety of mold types, bearing in mind that it would be more challenging for use with some molds than others. Automated Cleaning When the self-cleaning cycle is initiated, actuators in the mold position it for cleaning with precisely controlled gaps to ensure that flash does not travel beyond the target area. During the cycle, the vents are filled by overflow of PET from the preform, called PET flash, which then sticks to residue in the vents. The flashed preforms, complete with the residue, are then ejected, leaving cleaned vents behind. Self-cleaning is targeted in the neck ring area of the PET preform, the main area of residue accumulation in the mold cavity, and it enables a consistent and proactive cleaning of this target area before it becomes excessively blocked or clogged by the residue. With periodic cleaning of this target area, manufacturers can postpone more time-consuming manual cleaning. However, because it does not reach all areas of the mold in which residue can accumulate over time, self- cleaning does not entirely eliminate the need for some manual cleaning. It should still be scheduled as needed. Machine oper- ators should determine when to initiate a self-cleaning cycle, often based on scheduled mold maintenance or post-produc- tion part inspection. Automating the self-cleaning process is certainly a possibility for the future, however. A maintenance plan that combines self-cleaning technol- ogy with greaseless wear components can save as many as 400 hours of downtime per year and boost productivity by 5 per- cent. It can allow users to skip some of the traditional main- tenance interruptions of four to six hours and replace them with self-cleaning in a single extended cycle of the machine. One self-cleaning cycle lasts on average between 10 to 15 sec- onds, depending on machine configuration, application and cycle time. The automated self-cleaning process can be activated by the touch of a button on a human-machine interface screen and eliminates the need for the operator to enter the machine. It can also be performed as often as needed. With virtually no time penalty on production, self-cleaning helps to overcome the contradiction between cycle time and mold maintenance, and aids in increasing productivity by significantly extending manual-cleaning intervals. With virtually no time penalty on production, self-cleaning helps to overcome the contradiction between cycle time and mold maintenance, and aids in increasing productivity by signifcantly extending manual cleaning intervals. A system running self- cleaning mold technology does not entirely eliminate the need for traditional mold cleaning, but it does represent an evolution in cleaning technology.