PETpla.net Insider 12 / 2010

PREFORM PRODUCTION 25 PET planet insider Vol. 11 No. 12/10 www.petpla.net 11. Check that the decompression (pullback) time and posi- tion is not excessive. This should be set as low as possible to minimize the risk of poor nub formation, 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. 12. Check to ensure that the valve gate compressed air pres- sure is sufficient to close the valve stems properly. Typical pressures are in the range of 8 – 12bar (120 – 145psi). 13. Check hardware for worn, damaged or failed components, specifically the mould gate inserts, valve stems, valve stem seals, nozzle tips, tip insulators, and clogged core / cavity cooling channels. name ................................................................................................................ company ........................................................................................................... function ............................................................................................................. street................................................................................................................. city ................................................................................................................... country .............................................................................................................. phone ............................................................................................................... fax.................................................................................................................... e-mail................................................................................................................ credit card ......................................................................................................... expiration date.................................................................................................... name on card ..................................................................................................... PETplanet print Vol. 6: The Rapid Guide to Perfect Preforms by Rick Unterlander and Ottmar Brandau fax: +49 (0) 6221-65108-28 info@hbmedia.net www.petpla.net Order your copy now! 7. Check that the cooling time isn’t excessive for the preform being moulded. This typically ranges from about 1 to 3sec depending upon the preform wall thickness. Reduce time if necessary to minimize the nub solidifying and adhering to the gate. This may improve nub release during initial mould opening. 8. Check that the hold (packing) pressure isn’t too high to cause excessive swelling, especially in the last zone. Reduce as necessary. 9. Check that the valve gate close timing is adjusted prop- erly. This is typically 0 – 0.5sec for valve gate close delay. Minimize to improve nub formation. 10. Check that the hold (packing) time isn’t too little for the preform being moulded. Increase as necessary to improve gate formation. Table of Contents i..................................... About the Authors ii............................................. Introduction chapter 1.......................................... AA Level High 2..................................... Accordion Preform 3....................................Air hooks / Streaks 4............................................ Black Specks 5................................................... Bubbles 6.............................................. Burn Marks 7..........................Colour Streaking / Peeling 8.............................................. Crystallinity 9............................................. Drool Marks 10.......................................................Flash 11......................................Gate Depressions 12............................................ Gate Peeling 13.............................. Gate Voids / Pin Holes 14......................................Internal Gate Sink 15............................................ Internal Sinks 16.....................................................IV Loss 17........................................ Long Gate Nub 18........................................... Milky Preform 19.........................................Moisture Marks 20............................ Neck Finish out of Round 21....................................Parting Line Crease 22............................. Parting Line Deformation 23......................................Preform Yellowing 24...............................................Short Shots 25.......................................................Sinks 26......................................................Splay 27........................................Stretched Necks 28..................................................Stringing 29......................................Surface Blemishes 30......................................Thread Flow Lines 31.....................TSS (Top Sealing Surface) Sink 32................................................... Unmelts 33............................. Wall Thickness Variation 34..............................................Wavy Body 35...............................................Weld Lines prices in EUR + VAT. 1- 3 exemplar each 129,- € 4 - 10 exemplar each 99,- € > 10 exemplar each 69,- € PET planet print vol.6 The Rapid Guide to Perfect Preforms machine no./name