1 Plastic is mixed and shaped into pellets. The pellets are then placed in an injection molding machine, which heats the plastic until it is melted. A rotating screw or plunger forces the liquid plastic into the handle molds. The molds form the entire handle, including the small holes, called cores, into which the bristles are inserted. The molds are securely clamped, and pressure is applied to the molds while the plastic cools. Once the molds have adequately cooled, the clamps are removed, and small pins push the handles out of the molds.
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