Plastic boxes, like many other kinds of plastic containers, are created by a process called blow molding. Blow molding is one of the processes by which raw plastic material is converted into something useful. All blow molding processes are similar except for a few variations in process and machinery design; each blow molding machine begins with a collection of raw plastic resin (which is called stock) that is loaded into a hopper. The hopper directs the stock into a conveyance channel where a long screw forces it toward the mold. As the screw turns it creates friction and pressure that heats the stock. That pressure, combined with heat provided by heating elements along the channel, liquefies the plastic. At this point, the plastic can be forced into the mold cavity, which is an open area that is designed to shape the stock. The liquefied stock fits into the contours of the mold as it is forced into the cavity. Once it has taken the shape of the mold, compressed air is forced into the mold to make the product hollow. Then, after cooling and hardening, the newly molded product is ejected from the machine. Other containers that are used for long-term or repeated storage of foods can be made to withstand the high heat of a consumer dishwasher. A plastic box could also be used for shipping and distribution of products across long distances. Plastic boxes designed for applications in the health care industry can be sterile and non-porous, contributing to a healthier clinic or hospital environment. There are few differences between plastic boxes and plastic tubs or bins. The word "box" implies a smaller size than the word tub or bin along with a flat-walled, cube or rectangle-shaped construction. This can be true, though plastic boxes can be designed in many configurations.
