Single-screw extruders are continuous, high-pressure-generating pumps for
viscous materials that can generate thousands of pounds of pressure while
melting and mixing. These devices are most often fed by pelletized solids with
a regular geometry, such as spheroids and cylinders. Less common, and with
somewhat greater diﬃculty, the feed may be diced material, powders, granulations, ﬂakes, taﬀy, slurries, or melted material.