SUGGESTED PROCEDURE FOR EXTRUDER SCREW REMOVAL

SAFETY:
   
Do not use open flame near Bamberko Purging Compound extradate or the barrel opening. The fumes can  ignite. Use exhaust to ventilate the odor. Follow area safety rules

PROCEDURE:
Purge the extruder and die in the customary manner, when preparing for die removal.
Remove die, adapters, clamp rings, breaker plate, and screen pack. 
OPENING MUST BE FREE OF RESTRICTIONS.
Clean out previous resin from the hopper.

Raise the extruder temperatures to 450 degrees F. Use temp. 450 - 475 F when purging ABS, Nylon, Polycarbonate, PET or other high temperature resins. Barrel temperatures should be kept within a 350-475 F (176-246 C) range. 

Back out the pressure transducer and the rupture disc, 2 to 3 turns to protect the tip surface.

After the extruder temps. are reached, start the screw rotating at 80 to 100 rpm. The extradate should come out unmelted to produce the scrubbing effect. 

Feed Bamberko Purging Compound into the extruder, a small quantity at a time. Observe the motor load (amps) to insure it can handle the load. Estimated amount of purge compound to use is 2 pounds per inch of screw diameter. One or two volumes of the extruder capacity are all that is needed.

Minimize possible smoke and odor by purging into water.

Clean out the hopper, run until the barrel and screw are empty.

Immediately push screw out of the barrel and finish cleaning it with a wire cloth or a wire brush. This will prevent any of the purge compound, that is left on the screw, from melting to the screw. 

Clean the inside of the barrel with a flue brush on a copper pipe. Follow up with a cotton cloth draped over the flue brush.

Make sure that all purge residue (dust) is removed from the hopper, feed throat, and barrel.

Clean pressure transducer and rupture disc holes. Reappply anti-seez t the threads.

Re-assemble the extruder.

Hard Way Easy Way
Hot Polyethylene and 3 Operators Using Bamberko Ultimax 9100 Purging Compound

View Full Video on Screw Cleaning

Article by Earl E. Herriman

Updated 08/19/2002