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We are facing a problem of crystallininty in gate Area of 12.7 gm preform . Suggest plz remedies for this problem. rashid aliMaintenance aliMaintenance T Technician echnician of Husy in!ection molding Machines Stephen Stephen "enea #uality and $rocess %ngineer at $%T Terra Terra Systems What injection machine,mold manufacturer, cycle time? Water nish?
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Wendell Wendell he Mareting Manager at Taizhou Huiyuan Mould &o.'(td Pls contact with us and explain us in detail ,my email :
[email protected] ttmar )ttmar *randau $resident at Ape+ &ontainer Tech Tech ,nc. !oo" for water pressure and #ow in your $ate insert and cores. What is your injection, coolin$, and hold time and what hold pressure do you use? What is your $ate wall thic"ness? %f coolin$ is o"ay it could &e too hi$h a hold pressur pressure. e. 'i$h pressure can sometimes force the molecules into crystals as well.
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(aylan ( aylan Taylan Tumer plant manager at %ruslu non-oen group 'i, we need more detailed information as ttmar said. Process parameters such as injection, hold pressures and time and coolin$ time. )lso $ate thic"ness, type of the mold, ro&ot etc.. Some of the ca*ities or all of them? %f some ca*ities only increasin$ the no++le temps of that +ones would help. hec" coolin$ water temps and pressures. -ay&e also some deposits could clo$ the coolin$ water channels. %f this is the case, you ha*e to ta"e care of your water uality and cleanin$ such deposits is not *ery easy. /ou can tal" with your mold supplier and can add some clenanin$ chemicals to your chilled water system. We &uilt a small water circulation system in the past with a small pump, 'eater and chemical dosin$. 0*ery six month molds had &een connected to this system and we let the water circulate for one day. day. 1ut chemical is *ery important i mportant so Please chec" it with your mold supplier.
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rashid
rashid ali Maintenance Technician of Husy in!ection molding Machines (han"s -2.(aylan (umer for your su$$estions ./es there is no pro&lem with water uality and temp, pressure e*ery thin$ as per recommended procedure .(emp of water 34 c to 55c and pressure 6 to &ar is runnin$.mold ha*e 78 ca*ities and cycle time is 8.6 second is runnin$ .injection time is 3.43 sec and we try to reduce and increase to sol*e pro&lm &ut useless. (aylan Taylan Tumer plant manager at %ruslu non-oen group hi rashid, what a&out the outlet pressure of the coolin$ water. i mean after the mold? thic"ness of the $ate, holdin$ time and pressure, %9 of the raw material would help me to understand.
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Peter $eter Schumann $roduct and Application Manager (a Seda de *arcelona 'i 2ashid, could &e followin$: a*ity heater malfunction ca*ity temp. too low manifold temp. too low holdin$ pressure to hi$h coolin$ insu;cient core coolin$ inadeuate fountain in core rod dama$e $ood luc", Peter
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0 mhmd % mhmd Hendy factory manager at sama plas %ncrease no++le temp rstly ,try increse slowly mold temp ,decrease hold pressure hold time then chec" coolin$ system last may &e insulator of no++le may &e dama$e
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rashid rashid ali Maintenance Technician of Husy in!ection molding Machines (han"s -2.0 mhmd 'endy when we increased no++le tips temp we $ot $ood results 1ut after few days a$ain
same pro&lem we faced.
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donald donald mcmillan pacaging specialist could &e due to a heat sin", material &uild up, #ow issues or coolin$ of that ca*ity. ls it a outside or inside ca*ity. loo"in$ a dimensional data across mold could $i*e clues. $ood luc"
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0 mhmd % mhmd Hendy factory manager at sama plas -r rashid nothin$ i do . Feel free to as" We are co operate my friend try mold temp &efore hold
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rashid rashid ali Maintenance Technician of Husy in!ection molding Machines (han"s o" What a&out the *al*e $ate timin$ we are usin$ 3.= sec open delay this one can &e creat pro&lem.
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0 mhmd % mhmd Hendy factory manager at sama plas % thin" *al*e $ate not the main cause 1ut u must chec" the $ate .is the pro&lem still?
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ttmar )ttmar *randau $resident at Ape+ &ontainer Tech ,nc. !et>s recap: crystallinity can occur due to insu;cient coolin$ after injection or if the melt cools too much around the *al*e $ate. 1y increasin$ the no++le tips you
had some success so it seems the latter is the cause. /ou can therefore try to minimi+e the time that the *al*e stem is in contact with the cold mold. (hat means open it earlier until you $et drool, then add a little time to pre*ent that. (he delay open timer can &e timed o dierent e*ents in the injection process, li"e mold a&out to close, or ro&ot out. %f you cannot open early enou$h you can try a dierent timin$ e*ent pro*ided your machine has those options.
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Stephen Stephen "enea #uality and $rocess %ngineer at $%T Terra Systems o you ha*e the 'us"y set to maintain carria$e forward? What are your pull&ac" settin$s and *al*e $ate close delay? For a more &asic explanation, crystallinity is caused when the plastic is at the wron$ temperature AB563 to 5C3 de$ D for too lon$ a time. (hou$h crystallinity can form anywhere &etween the Elass (ransition (emperature and the -elt temperature it crystalli+es fastest at the exothermic pea" on the S cur*e. /ou should &e openin$ your *al*e $ates at the earliest moment after mold &rea" to "eep the *al*e stem from &ein$ in contact with the chilled mold. (here is a settin$ to open the *al*e $ates on mold open. /ou may e*en &e a&le to enter a ne$ati*e time to $et closer to true mold open. /ou will need to ensure you>re decompressin$ the mold with adeuate 9E and pull&ac" to a*oid drool. )fter that, as mentioned a&o*e, adjustin$ no++le tip output to minimi+e the crystallinity is important. Sometimes % ha*e also had to adjust water #ow to the hemispherical &ase area on thin wall applications.
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rashid rashid ali Maintenance Technician of Husy in!ection molding Machines dears i am *ery than"ful all of you people for your help full sharin$s . (oday we chan$ed *al*e $ate settin$ from mold close start to mold open end, then we $ot $ood results and also put *al*e $ate close delay time 3 &efore this one 3.= sec . o" if we faced a$ain pro&lm than % will detru& all of you a$ain . (')<S )!! -0-102S.
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0ddie %ddie AlaradoToledo operador machine hi$h tips and hi$h temperature mould
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0"&al %bal Hossain MA/A0% $%T ",3,S,)/4 at &A/S 5 A()S6%S $4 (T". -r. 2ashid )li, % am su$$est some remedies for this pro&lem as follows, G5H %ncresed hot runner no++le temperature. G=H hec" no++le insulatin$ cap. GIH Set preform coolin$ water temperature at C de$ree . GJH %ncrese preform coolin$ time. G6H ptimise holdin$ pressure donald donald mcmillan pacaging specialist chec" runners, ensure all heatin$ and coolin$ lines are free,
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ttmar )ttmar *randau $resident at Ape+ &ontainer Tech ,nc. 1y openin$ the *al*e $ates earlier you reduced the contact time of the *al*e stem with the cold mold and that was the pro&lem. 1ut &y reducin$ the delay close timer to 3 you actually added 3.= s to the contact time. (he 3.= s it was set to was to reduce the stress in the preform durin$ screw decompression. % would lea*e it at that as you mi$ht $et other pro&lems &y settin$ it to 3.
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muthu"umar muthuumar mudaliar $(A/T MA/A0% at /,SHA/T M)6"(,/0S $3T. (T". (he main reason for this pro&lem is low no++le temperature or dama$ed no++le tip insulators.
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Era*es 0raes 0ee Taizhou Huangyan %+pedition Machinery &o.'(td Mareting Manager rystal nec" of preform need to modify the cap si+e.
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mamdouh mamdouh elhamala-y 8actory Manager at A9uah 0roup &ompany 0xa$$eration &y increasin$ the no++le tip temperature will possi&le cause a new Kuality pro&lems.
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mamdouh mamdouh elhamala-y 8actory Manager at A9uah 0roup &ompany &y increasin$ the no++le tip temperature, the material temperature is "ept a&o*e this area so that it does not reach easily in the a*aila&le time the crystallisation area.
