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how to calculate screw torque

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Topic: how to calculate screw torque

jmgonnet
Member

Posts: 1
From:Germany
Registered: Sep 2009

posted October 19, 2009 04:24 AM

Hello,

I am dealing more and more with the refurbishement of PVC extruders to make HFFR product.
With HFFR compounds we have some difficulties to get high output (sometime no output at all) with the existing motorisation. One of the main problem is to get a motor overload (high current)
I would like to know if there is any tips to use to calculate screw torque ?
Also, why in the literature, we say extruder are running at constant Torque ?
Thanks in advance for your help .
regards.

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Tom C
Moderator

Posts: 965
From:Brodheadsville, PA USA
Registered: Jun 2001

posted October 19, 2009 08:41 AM

The motors used in extrusion are capable of supplying the same maximum torque no matter what speed it is running.

It is likely that the screw design you are using is too deep for the motor power you have available. By being too deep the power required to turn the screw exceeds the avaiable power, stalling the screw.

------------------
Best Regards,

Tom Cunningham

www.ExtrusionTechnicalServices.com

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