Window Profile Trouble Shooting Guide

Problem Possible Cause Possible Solution
Excessive motor amperage Early fusion Reduce rear barrel temperature to avoid early fusion
Reduce oil temperature of screw
Use a slower fusion compound
Excessive back pressure Increase die temperature to decrease back pressure
Increase orifice size in adapter to reduce restriction on screws
Lower output to decrease throughput
Increase barrel and screw temperature to increase melt temperature
Increase die temperature to decrease pressure in die
Increase orifice size
Use a more externally lubricated compound
Excessive feeding Decrease feeder speed to reduce material in feed throat
Orange peel Melt temperature too cold Increase temperatures on barrel and screw
Lube imbalance or contamination Purge extruder again as purging itself could be the source
Line speed exceeds tooling reduce line speed
Melt rough on sides only Increase screw oil temperature
Lumps (small) Insufficient fusing at vent Increase rear barrel temperature
Increase screw oil temperature
Insufficient mixing in metering zone Decrease orifice size
Rough edges Increase die temperature
Increase melt temperature
Check die for blockage
Grainy surface Insufficient vent Increase vacuum
Cooling water temperature for vacuum pump to high Check water, vent, pump and filters for proper operation
Melt temperature too high Reduce barrel and Screw temperature
Volatiles are sealed in at vent Reduce rear barrel temperatures
Line is running too high Reduce speed or adapt tooling and formulation
Swirls Delayed fusion Increase rear barrel temperature
Increase screw oil temperature
Insufficient pressure at screw tips Decrease orifice size in adapter
Blisters Material wet Dry it by pre-heating
Increase vacuum
Severe pressure drop at tooling Change orifices
Heat Sinks Melt temperature too cold Increase extruder temperatures
Die is too cold (small heat sinks) Increase die temperature
First calibrator too cold Increase temperature / decrease water flow
Insufficient vacuum Increase vacuum carefully
Dimples (in a straight line) Water is leaking onto profile in first calibrator check first calibrator
Dimples (at random) Air bubbles forming on profile in water tank between first and second calibrator Increase water velocity / temperature
Low gloss Melt temperature too low Increase barrel and/or die temperature
Water contact with profile too early Delay water contact
First calibrator too cold Increase calibrator temperature
Decrease water cooling by decreasing water flow to calibrator
Scratches/Drag Lines Calibrators too new Keep on using
Vacuum too high Decrease vacuum (without affecting sizing)
First calibrator too cold Increase calibrator temperature
Water temperature too low Increase water temperature
Poor impact Melt temperature too low Increase barrel temperature
High moisture content of material Check material in hopper
Check venting to be sure volatiles are all removed
Increase rear barrel temperature
Material over fused at vent and sealing in volatiles Decrease rear barrel temperature
Profile bowing (to the left) Die out of balance correct die geometry
Uneven cooling Add more cooling to the left side or reduce cooling on right side
Too much make up water entering tank from right side
Chatter Calibrator misalignment in tank adjust calibrator
Vacuum too high (therefore to much drag in calibrator) Decrease vacuum
Puller Air pressure/clamp force too low,slipping
Puller drive not stable
Profile over size, pinching in calibrator
Cooling water too cold, profile shrinking too fast Increase water temperature
Water making contact to early Delay water making contact after skin is set in first calibrator
First calibrator too cold Increase temperature
Profile is too tight in seal on end of tank
Sudden loss of die balance Die temperature too high Check thermocouples, controllers
Check extruder barrel temperatures
Check all extruder barrel heater bands
Check die heater band for even heat
Flank Play Check flank play on extruder screws
Blockage in die Clean die
Plate-out in calibrators (there are many theories) Increase fusion of material as much as possible on rear of screws, but do not over fuse
Increase melt temperature to 200 C - 205 C
Increase temperature of first calibrator. Over chilled calibrator increases plate-ou
Most plate-out occurs in first calibrator and is transferred to other calibrators with the profile