extruding high melt flow polymers

[alang]

We have a Filabot EX2 extruder with a meager 12 L/D ratio. We want to make some 2.85 nylon filaments with some special fillers. So far, I've only had experience with the EX2, and have a few questions:

My understanding and brief experience is that the EX2 can't provide enough shear to adequately melt/mix the polymer to produce a consistent filament. Are there ways to mitigate this issue, such as slowing down the extrusion?

Anyone have suggestions for extruders that would be capable of extruding nylon with high filler content, or at least help me understand what I should look for?

What about suggestions for vendors that could potentially make this filament for us if we send them the material?

thanks

[filabotcom]

We have had some limited success in our lab making nylon filament on the EX2, the resulting feedstock was usable on our printers in testing but did not fall within the +/- .05mm tolerance that we generally look for as a sign of success. Most of these experiments were done in the past, prior to the design of the EX6, which is the machine in our lineup that we recommend to users who intend to work with nylon. The shorter screw and single heat zone on the barrel of the EX2 means that there is a short window to achieve melt flow in the polymer, though you can increase that window by slowing the speed of the screw. You could also try increasing the temperature on the heat zone if you are still experiencing unmelt- if you have a way to measure the temperature of the polymer in the extrusion such as an independent probe or thermal camera you may find that the plastic is moving quickly enough through the screw that it isn't reaching the same set temperature as the barrel.

Filabot offers full trade-in value on an EX2 towards the purchase of an EX6 if you decide you would like to upgrade to a more powerful machine with a longer screw and multiple heat zones.