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  Problems with HIPS recycled

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Author Topic:   Problems with HIPS recycled
gustavo
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Posts: 2
From:
Registered: Jul 2003

posted July 30, 2003 12:50 AM     Click Here to See the Profile for gustavo   Click Here to Email gustavo     Edit/Delete Message   Reply w/Quote
Please, someone help us!
We produce a simple profile in HIPS recycled in a single screw extruder (LD 30:1, 2.5" diam.) we usually produce 7 fts per minute (around 80 pounds per hour) but now our productivity goes down and we cannot produce nothing. If we try to run at 20% of the normal we start having problems with the flow. The tempertures are: 320,356,320 and in the die 320 too) usually we can process HIPS at this temperatures but now the flow is too irregular.

Please help me, we need to finish an order tomorrow!!!

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Steve H
Moderator

Posts: 221
From:New Zealand
Registered: Jun 2001

posted July 30, 2003 01:36 AM     Click Here to See the Profile for Steve H   Click Here to Email Steve H     Edit/Delete Message   Reply w/Quote
Hi Gus

Welcome to the single screw forum. What form is your feed in, flake or pelletized? Has your source of supply changed, have you got a load of repro that has a high concentration of a slip/denesting additive?

What's happening with your melt temp, melt pressure and screw motor amps. Is the screw turning, is it turning at the indicated speed?

Has the problem started suddenly, or has output been dropping gradually for a while?

Have you tried some different feed zone temps.

Steve H

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BrianAndLiz
Senior Member

Posts: 38
From:S&M Molding WebsterNew York
Registered: Nov 2002

posted July 30, 2003 02:37 PM     Click Here to See the Profile for BrianAndLiz   Click Here to Email BrianAndLiz     Edit/Delete Message   Reply w/Quote
Check to make sure everything is set right. You might have knocked somthing (seemingly) minor out of wack.

Once, at a company I worked for... we had 16 hours of scrap because someone turned off the Mokon by accident.

After you go over that... check to make sure everything is running right. Is the moter/gears/screw turning at the right speed? In the right direction? Air pressure ok? Temps set right? Resin recipe to spec?

After that... blame the resin.

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Steve H
Moderator

Posts: 221
From:New Zealand
Registered: Jun 2001

posted July 30, 2003 02:50 PM     Click Here to See the Profile for Steve H   Click Here to Email Steve H     Edit/Delete Message   Reply w/Quote
Gus

Another posibility to check- are you cooling the feed throat of your machine. HIPS can be quite sensitive to melting and sticking to the feed hopper/feed throat, and bridging. No feed to the screw, no output.

Your die heats seem quite low too, is cooling a problem with this profile?

Steve H

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