Posts: 1
From:Ontario, Canada
Registered: Jul 2005

posted July 18, 2005 03:59 PM            

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Question: in designing hollow profile for plastics ..what precautions or parameters to be considered to insure or improve the seam of the extrudent?

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Posts: 95
From:Silver City, NM, USA
Registered: Jun 2001

posted July 18, 2005 10:52 PM               

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If you use twin screw extrusion, at least a 3:1 compression ratio from head to die opening is suggested, to insure that the melt is completly fused with no "seams" or weld lines.

Single screw extruders, with higher screw RPMs and higher shear, can suffice with lower,1.5--2.0:1 compression ratios from head to die opening.

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Posts: 125
From:Allentown, PA - USA
Registered: Jun 2001

posted July 19, 2005 03:51 PM            

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Depends on the material in most cases.

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