|Particle Size Enlargement
- The chief methods are: compression into a mold, and extrusion through a die, followed by cutting or breaking to size; globulation of molten material, followed by solidification; agglomeration under tumbling or otherwise agitated condtions with or without binding agents.
- Tablets are made in rotary compression machines that convert powders and granules into uniform size pieces. Ususally maximum diameter is about 1.5 in., but special sizes up to 4 in. are possible. Machines operate at 100 rpm or so and make up to 10,000 tablets/min.
- Extruders make pellets by forcing powders, pastes and melts through a die, followed by cutting. An 8 in. screw with a capacity of 2,000 lb/h of molten plastic is able to extrude tubing at 150-300 ft/h and cut it into sizes as small as washers, at 8,000 pieces/min. Ring pellet extrusion mills have hole diameters of 1.6 to 32mm. Production rates are 30-200 lb/(h)(hp).