PETpla.net Insider 06 / 2011

PREFORM PRODUCTION 11 PET planet insider Vol. 12 No. 06/11 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 8. Check that all thermocouples are properly inserted and con- tacting the bottom of the wells. 9. Check that the decompression (pullback) time and position is not too little. This should be set high enough to ensure the melt pressure is being released, yet as low as possible to minimize the risk of drawing in air. Typical settings for valve gated moulds are: Time = 0 – 1sec; Distance = 0 – 10mm. Non-valve gated moulds may require higher values to mini- mize gate stringing. With a long story in packaging engineering SIPA can support its customers on lightweight preform development as well as preform lightweight conversions on existing mold. SIPA has developed specific neck ring design solutions for an optimal cooling and cycle time, even in case of short preform and neck finish conversion. SIPA provides complete preform mold for any PET system (up to 96 cav.), cold half for existing hot half (up to 144 cav.), hot half for existing cold half (up to 96 cav.); furthermore it provides conversions of existing mold (full or partial kits), mold spare parts and refurbishment. All SIPA preform molds feature LongLife ™ , a new design engineered to extend the mold service life. LongLife ™ PET preform molds with strong focus on lightweight. www.sipa.it 10. Check the valve gate open delay timer and increase as necessary to release preform pressure. Typical settings are 0 – 0.3sec. This adjustment must work together with decom- pression (pullback) time. 11. Check hardware for worn, damaged or failed components, specifically the cavities, and clogged core / cavity cooling channels.