Clear Plastic Tubing
Clear plastic tubing is a hollow, usually cylindrical body of thermoplastic material, used either for conveying or containing liquids or gases or as structural components. Clear plastic tubing must be made from plastics that are naturally clear. The two clearest plastic materials are
acrylic and vinyl; both are particularly useful for applications that require visible fluid movement. Another naturally clear plastic is
polycarbonate, which offers high impact resistance as it is next to impossible to break and is often used in electrical applications due to its high dielectric strength and high volume resistivity. Additional clear plastics include PVC, PETG and polyethylene for applications such as air and gas lines, chemical lines, protective jacketing, water and fluid lines, refrigeration and packaging. Industries that use clear plastic tubing include food and beverage, material handling, pharmaceutical, chemical processing, industrial, marine, optical, architectural and commercial. Clear plastic tubing can often be
medical grade tubing, which is typically made from FDA approved materials, and is often used in medical and surgical applications such as IV lines and catheters.
Clear plastic tubes are made through the profile extrusion process. The 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. In order to form clear 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 clear tube. The newly formed clear plastic tube is instantly cooled with cold water where it solidifies. Lastly, the clear 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.