posted January 14, 2005 07:16 PM               

For profile extrusion each of the materials will need to be of sufficient viscosity to hold the shape outside of the extruder. Some of the listed resins are normally high in viscosity and others will require specialty grades.

All of the resins should be dried in a low dew point dryer. Some need to be dried to less than 0.025%

A few of the resins will require barrel heaters that can run higher temperatures than aluminum heaters can handle. Ceramic or Bronze heaters are the options. Very high viscosity resins will also require barrel cooling. For small diameter extruders air cooling is sufficient but difficult to implement with ceramic or bronze heaters.

Only PEEK is very corrosive becasue of added PTFE. Careful selection of materials of construction is required for PEEK.

A single screw extruder is best for the materials listed. It is a very efficient pump when dealing with high viscosities. I would suggest two screw designs at a minimum. One for the amorphous resins which melt easier and mave higher viscosity. The other for the crystalline resins which melt slower and are typically lower in viscosity. A vent is not rquired if the resin is dried peoperly and the screws are appropriate.

Often adaptor tooling has fewer heaters and fewer control zones than required to deal with many of these high temperature resins. Make sure your covered.

Many of these materials are very difficult to deal with because they harden at high temperatures. Make sure the die tooling is designed to be taken apart easily for cleaning because process interuptions can often result in blocked areas of the die.

Good Luck,

Tom C