Square Plastic Tubing
Square plastic tubing is a square hollow device that is used to convey fluids or gases or as structural components. Square plastic tubing manufacturers utilize numerous plastic compounds in their product lines including polyurethane (PU), Santoprene (a thermoplastic rubber), flexible vinyl (FPVC), polyvinyl chloride (PVC),
polycarbonate (PC), rigid vinyl (RPVC), ABS, high impact polystyrene (HIPS) and PETG. Typical applications that require square plastic tubing versus the more common cylindrical
plastic tubing include POP displays and products in the health and beauty, toy, and houseware markets as well as being an excellent choice for packaging sharp or heavy objects that require extra protection. Square plastic tubing offers all of the same beneficial characteristics of cylindrical plastic tubing such as anti-static, reinforced (including fiberglass and steel wire reinforced), resistant to heat, spark and flame, explosion proof, multi-colored, multi-element or co-extruded and double walled or multi-layered. Since there is such a wide range of materials that can be
extruded into plastic square tubing, the intended application will certainly narrow the choices; for instance, square plastic tubing may be made from flexible, rigid or semi-rigid materials and suit different applications depending on the tubing's flexibility.
Made through the extrusion process, square plastic tubes are both durable and cost-effective. To begin the extrusion process plastic resin pellets, also called nurdles, are fed into the extruding machine's hopper, which is a funnel-shaped receptacle through which contents pass by gravity into a receptacle below. The receptacle contains a screw conveyor, which by rotating its screw, serves to continuously convey the plastic pellets forward. In addition, the receptacle is heated and the plastic pellets are being softened by both heat and friction as they are conveyed forward. By the time the plastic pellets comes to the end of the screw conveyor, the plastic pellets have become "plasticized", or made completely molten. On the end of the conveyor channel a die orifice is secured which forms the molten plastic into a specific profile as it is pushed, or "extruded" through by the screw conveyor. The die is a shaped metal piece that differentiates cylindrical tubing from square tubing; it will be a square shape for square tubing. In order to form square plastic tubing, a pin or mandrel must be placed inside of the die and a positive pressure is applied to the internal cavities through the pin. This creates the hollow inside of the square plastic tube. The newly formed tubing is instantly cooled with cold water where it solidifies. Lastly, the plastic square tube is conveyed onwards by take-off rollers, which actually pull the softened plastic from the die, to a series of conveyors and is then cut to length.