PETpla.net Insider 06 / 2010

PREFORM PRODUCTION 21 PET planet insider Vol. 11 No. 06/10 www.petpla.net 3. Check that the cooling time is sufficient for the preform being moulded. This typically ranges from about 1 to 3sec depending upon the preform gate thickness. Add time if necessary to improve gate / dome solidification. 4. Check the valve gate close delay timer and decrease as necessary to maximize nub cooling. Typical settings are 0 – 0.3sec. 5. Check nozzle tip heat settings. This area has a major impact on gate peeling. Settings too low may cause the melt in the nozzle tip area to solidify, causing a higher resistance to nub separation during initial mould opening. The settings should be raised enough to allow the nub to separate easier, yet not too high to cause overheating related problems. 6. 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 – 10bar (120 –145psi). 7. Check hardware for worn, damaged or failed compo- nents, specifically the mould gate inserts, worn valve stems, nozzle tips, tip insulators, and clogged gate insert cooling channels. 12. Gate Peeling 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 prices in EUR + VAT. 1- 3 exemplar each 129,- € 4 - 10 exemplar each 99,- € > 10 exemplar each 69,- € Symptom: A torn section on the exter- nal surface of the preform, starting from the gate nub extending outward toward the dome area. Typically curly or spiral in shape. Cause: The preform gate nub has not separated properly from the mould gate during the initial mould opening sequence (core side sepa- rating from cavity side). Solutions: 1. Check water cooling temperature. This should be 7 – 10ºC (45 - 50ºF) for optimum cooling. 2. Check water cooling flow to mould. This should be at the mould manufacturers rating (for a given preform size and cavitation). 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 fax: +49 (0) 6221-65108-28 [email protected]  www.petpla.net Order your copy now!