PETpla.net Insider 03 / 2011

PREFORM PRODUCTION 33 PET planet insider Vol. 12 No. 03/11 www.petpla.net fax: +49 (0) 6221-65108-28 info@hbmedia.net www.petpla.net Order your copy now! PET planet print vol.6 The Rapid Guide to Perfect Preforms machine no./name ol prices in EUR + VAT. 1- 3 exemplar each 129,- € 4 - 10 exemplar each 99,- € > 10 exemplar each 69,- € .6 .6 .6 l. l ol Symptom: Faint white swirls and patches in various spots on the preform. Cause: Melt that has been thermally degraded by overheating in a spe- cific zone (not oxidized). Solutions: 1. Check all temperature readings and correct if necessary. PET resin should be melted at about 280ºC (536ºF) +/- 10ºC (18ºF). 2. Check all %-controlled temperature settings and mini- mize if possible. %-controllers provide no temperature feedback and require fine tuning. 3. Check that all thermocouples are properly inserted and contacting the bottom of the wells. Having a ther- mocouple incorrectly seated in one zone has a major effect on this problem, especially if the melt stagna- tion time between cycles is long. 4. Make sure the extruder screw cushion is not exces- sive. This should be a minimum of 25mm to com- pensate for any fluctuations during screw recovery. (Two-stage machines only) 5. Check hardware for worn, damaged or failed com- ponents, specifically the machine and mould heaters, and thermocouples. 6. For prevention, always: a. Reduce temperatures by about 40ºC (104ºF) if the machine stops for more than 15min b. Reduce %-controllers by ½ if the machine stops for more than 15min c. Shut off nozzle tip heats if the machine stops for more than 10min d. Never exceed start up temperature soak times. Machine should be started within 15min of the tem- peratures reaching operating settings. Nozzle tips should only be turned on 5 to 7min prior to start up. IN EVERY BOTTLE THERE IS ALL OUR KNOW HOW. G:H:6G8= 9:K:ADEB:CI 6 XdchiVci egd_ZXi^dc idlVgYh i]Z [jijgZ dg^ZciZY id hZVgX] cdi dcan [dg cZl bViZg^Vah Wji Vahd cZl E:I iZX]cdad\^Zh d[ igVch[dgbVi^dc VcY ^ccdkVi^kZ bViZg^Vah# 8DCHJAI6C8N 6 XdcXgZiZ VchlZg id Vaa ndjg fjZhi^dch# LZ eji Vi ndjg Y^hedhVa Vaa djg `cdl"]dl [dg ZkZgn h^c\aZ gZfj^gZbZci# EGDIDINE6I>DC EgdidineZh d[ XdciV^cZgh VcY ^ccdkVi^kZ egZ[dgbh ^c gZXdgY i^bZh/ ndj l^aa WZ VWaZ id idjX] l^i] ndjg ]VcYh i]Z WdiiaZh l^i]^c V h]dgi i^bZ V[iZg VeegdkVa d[ i]Z YZh^\c# 9:H><C 8gZVi^k^in ^c hZVgX] d[ ZaZ\VcXZ VcY gZÒcZbZci# >ccdkVi^kZ YZh^\ch! Zg\dcdb^X higjXijgZh! ZnZ"XViX]^c\ VcY [jcXi^dcVa XdciV^cZgh# LZ \^kZ V igjZ h]VeZ id ndjg egdYjXi 33