Plastic Extrusion Made Simple

Human beings are inherently curious creatures, and indeed, without this natural attribute, it is doubtful if we would have advanced as far as we have. Curiosity drives us to discover new horizons, to look for new and better ways to do things, and to question everything. It's not surprising then, that people not involved in manufacturing, or who have never been inside a factory, are often quite curious about how ordinary, every day commodities such as plastic, are made. Even the science involved in the plastic extrusion process is interesting, and how the industry has developed different types of plastics. While ordinary people may not quite know how it's done, they can appreciate it.

Most people wouldn't know that the life cycle of PVC Plastic starts in raw material form as powder or pellets. This plastic material is added to a machine known as an extruder, and is propelled forward through the machine by a rotating screw. This rotating screw lies inside a cylindrical shaped heated barrel and as the plastic material passes through, it softens from the friction and heat.

The plastic material, now softened, is a continuous piece which is pushed through a die at the end of a barrel and is cooled and solidified in water. Still on a moving conveyor, the softened extruded material is pulled through take-off rollers and off the die, which is a metal plate attached to the end of the extruder. This die has a hole cut into it to match the desired shape of the plastic. The cross-section of the finished plastic depends on the speed of the take-off rollers and the shape of the hole in the die.

There are a number of different extrusion processes used depending on the type of material needed and the specifications of the client. For example, with co-extrusion, different types of plastic can be produced in the same production line.

The extrusion process is completely automatic, and while the initial purchase of the machines is expensive, there are considerable cost savings in labor throughout the life of the machine. The continuous dimension checks and automatic machine adjustments allow the plastic manufacturers to make anything from simple tubes and rods to complex window profiles. Extrusion also allows for the production of larger items right up to pipe with a dimension of 150cm.

The engineers who originally conceived the idea of the plastic extrusion process were quite remarkable. Plastic can now replace materials such as metal in a wide variety of ways. As it is cheaper to produce, costs across the board are lower. Uses for light-weight plastic have opened up new markets and expanded the range of inventions. It's hard to see that plastic will ever become obsolete.


------

PVC plastic is just one of the many varieties that plastic manufacturers, Pacific Plastics http://www.pacplas.com.au/ produce through their plastic extrusion process.