Plastic recycling machine - GIF

[Hoosiersmoker]

[QUOTE=jdurand;173010]the plastic goes into a big screw inside that pipe and is forced through a heated section where it melts. From there it's pushed through those little holes at the end to make plastic rods like a pasta machine. They're run through a water bath to cool them, then into a chopper to make short pellets from them.

I'm surprised they don't just have a spinning knife right at the extruder like is done with pasta.

About 42 seconds into this video. You can see the round screw tube but it's not heated for pasta.

The strands are too soft immediately out of the extruder to chop, they need to be cooled to solidify them a little. Especially HPDE is quite soft. Pelletizing isn't alway necessary either. Many extrusion processes can use flaked medium now requiring only a fine screened grinder to do the work. You could buy 10 or 12 grinders for the cost of one pelletizer, run them cheaper and process scrap considerably faster.