PETpla.net Insider 11 / 2012

PREFORM PRODUCTION 21 PET planet insider Vol. 13 PET planet print vol.6 The Rapid Guide to Perfect Preforms machine no./name 1- 3 exemplar each 129,- € 4 - 10 exemplar each 99,- € > 10 exemplar each 69,- € prices in EUR + VAT. 10. Check that the decompression (pullback) time and position is not excessive. This should be set as low as possible to minimize the risk of melt backflow into the nozzle tips, yet enough to eliminate drooling into the cavity from excess melt pressure. Typical settings for valve gated moulds are: Time = 0 – 1sec; Distance = 0 – 10mm. Non-valve gated moulds may require higher values to minimize gate stringing. 11. Ensure the mould neck insert and lock ring vents are clean. This will minimize the restric- tion to melt flow due to gas / air entrapment. 12. Check that no anoma- lies are present on the moulding surfaces and robot cooling recepta- cles. Repair if neces- sary. 13. Maximize the cool- ing time of the robot. This should not be increased beyond the cycle time of the machine. 14. Check to ensure that no moisture exists on the moulding surfaces, either from water leaks or condensation. This may obstruct normal melt flow and cause fill- ing problems. The envi- ronmental dewpoint should be below the chilled water tempera- ture to eliminate the risk of condensation. 15. Check for leaking core-air blow valve. Air pressure in the cavity during filling may restrict proper melt flow. 16. Ensure preform han- dling is not congested at the deposit locations and collection bins. 17. Check hardware for worn, damaged or failed components, specifically the mould cavities, robot recep- tacles, and clogged cavity and robot recep- tacle cooling channels. www.petpla.net PETplanet print Vol. 6: The Rapid Guide to Perfect Preforms by Rick Unterlander and Ottmar Brandau fax: +49 (0) 6221-65108-28 [email protected] www.petpla.net Order your copy now!