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| Author | Topic: High moisture content |
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rusticpixi Member Posts: 3 |
posted June 18, 2003 08:55 PM
   
New to the extrusion game, I ve come accross occasions when operators are blaming high moisture levels for poor quality extruded material (wood composite) Can someone explain this to a mere duffer? IP: Logged |
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extrude Member Posts: 1 |
posted June 20, 2003 02:01 PM
That depends on what type of resin you are extruding. Some resins are hygroscopic which attract moisture and therefore must be dried before you extrude them and there are resins that you can extrude right out of the gaylord. IP: Logged |
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Steve H Moderator Posts: 196 |
posted June 20, 2003 04:08 PM
G'day Welcome to the single screw forum to you both. Moisture in (or on) the material can cause a number of problems when extruding a product. Intermitant lines along the lenght of the product, blisters or degredation of the material, are some of the problems it might cause. I assume that you are using HDPE or PVC with wood, what are you doing to dry the wood content of your feed. Neither HDPE or PVC generally need drying, but if you are storing you material in a cold warehouse and bringing them into a nice warm extruder bay just before they are needed, condensation could be the cause of your problem. Just some general thoughts, come back and tell us: What polymer you are using What drying steps Is the barrel on your extruder vented And perhaps someone will come up with some other suggestions Steve H IP: Logged |
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rusticpixi Member Posts: 3 |
posted June 20, 2003 09:41 PM
Thanks for the interest thus far..... The compound arrives ready mixed ( a 2 day journey from the compounder) and is stored in plastic lined gaylords. Yes, the barrel is vented and the wood content is not wood, but another organic substance. Hope that this helps IP: Logged |
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Steve H Moderator Posts: 196 |
posted June 21, 2003 04:30 PM
What is the product you're extruding, sheet, profile? A little more info on the polymer would be helpful Steve H IP: Logged |
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rusticpixi Member Posts: 3 |
posted June 21, 2003 06:45 PM
Steve, The extrusion is a profile, 4 cells with webs between and a wall top and bottom. I really don't know what the polymer is sorry. I'll try to find out more and get back to you. IP: Logged |
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