| TROUBLE SHOOTING
| TROUBLE SHOOTING
GUIDE FOR GENERAL EXTRUSION |
| PROBLEM |
POSSIBLE CAUSES |
SOLUTIONS |
| NO EXTRUDER OUTPUT |
Hopper empty. Hopper feed
throat bridge Complete screw bridge. |
Fill hopper. Cool hopper feed
throat locket. Clean feed throat coolent Channel. Do not use hopper
dryer. Cool rear barrel heat zone to 150 �C or less Internal screw
cooling first 4-5 turns of feed section. Cool hopper feed throat jacket.
Calibrate rear barrel heat zone controller. |
| EXCESSIVE EXTRUDER DRIVE
POWER REQUIREMENT |
Rear barrel heat zone too
low. Barrel heat zone over screw transition zone too low. Melt temp.
too low. |
Increase rear barrel temperature
Increase temperature of barrel heat zone over screw transition zone
Increase barrel temperature. Increase screw rpm to increase shear
working. |
| SURGING |
Screw design Extruder drive variation
Improper temperature Gradient (barrel) Improper water circulation
in feed section. (Grooved feed barrel) improper mixing of end trim
|
Select screw with Metering zone Higher
compression ration. More shallow metering depth. Feed zone atleast
25% of length. Gradual transition. Check drive performance. Increase
barrel feed zone & Compression zone temperature Reduce screw speed.
Clean water circulation path with anti-sealing solution. Increase
water flow rate. Check water temp. (inlet & outlet) Adjust and
trim feeding system. Minimise film shiffting. Check quantity of end
trim. |
|
Courtesy: Mr. P.M. Jariwala, Kolsite Industries
|
