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| Author | Topic: pet sheet extrusion |
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wvzamora Member Posts: 2 |
posted December 16, 2004 06:37 PM
   
Hi: I am trying to produce 0.01" thick sheet from regring of pet bottles is a single screw 6" extruder with a coat hanger flat die and chilled rolls, and surging is tremendously high. Since I have no experience with PET, I can't start to figure out a solution. Can anyone help me out here, I'll really appreciate it. regards Walter IP: Logged |
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Tom C Moderator Posts: 415 |
posted December 17, 2004 07:23 AM
Could be that the PET flake is having trouble getting into the extruder. Typically the flake will lock up in a hopper preventing good feeding. Sometimes a low compression screw (3:1) can't feed enough flake to the rest of the screw resulting in surging. A high compression screw is recommended, but can casue problems if more dense material is fed. We have also developed an excellent performing barrier screw for this purpose. Please email me for more details. Tom C IP: Logged |
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wvzamora Member Posts: 2 |
posted December 17, 2004 09:44 AM
Thanks for your reply Tom. What we are using, is groung preforms, so it is not a very light material as flake, however, We manually fed the hopper making sure that the material would not bridge. Since this is not falkes, I don't think we need a high compression screw. The temperatures we used were from 520 deg F down to 500. Do you have any other suggetions? regards Walter IP: Logged |
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Steve H Moderator Posts: 331 |
posted December 17, 2004 05:58 PM
Hi Walter Welcome to the Single Screw Forum, what L/D etc etc is the screw you are using, how are you drying the regrind,(drying temps, residence time) Steve IP: Logged |
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