Polymer Industries uses typically process that is known as ram extrusion for producing profiles, sleeves, rod, blocks, tubing, lining sheet bars etc. The following image shows how a bar is extruded using RAM extrusion. The ram extrusion process proves very effective for specific materials which are not extruded successfully using screw extruders. The example can be given of PTFE resin. Plastic material in the powder form is gravity fed into a chamber. A hydraulic ram is used to push this powder from chamber to the die. The die actually gives the shape of the desired plastic. Whether a rod, tube, or a profile shape with requisite internal/outer diameter the die is there to give the shape. Heaters put outside the die heats up the plastic and give the form the shape of die. The powder is continuously fed into the die by the back and forth movement of the hydraulic ram. When the material finally comes out of die, it moves the length of the conveyor and subsequently it is cut to length.

Ram extrusion offers a big advantage it does not shear the material, that is manufactured. This is unlike a single screw extrusion. It pushes the material through the die into a desired shape by the process of hydraulic push. Ultra high molecular weight polyethylene, PE, becomes gelatinous as it melts so it can be extruded with this type or other similar processes.

Types of RAM Extrusion
Whatever be the type of RAM extrusion, the processing guidelines are the same. They are resin feed, compaction or performing, sintering and cooling. RAM extrusion process can be divided into two categories.

• Vertical Ram Extrusion
• Horizontal Ram Extrusion

Parameters to be considered in RAM Extrusion
A variation in the parameters invariably affects the quality of the extrudates. That is the reason why they must all be given a careful consideration. The following are the parameters:

• The design of the extruder
• Powder properties
• Extrusion rate
• Pressure and temperature

RAM Extruders : Aiding the RAM extrusion process RAM extruders are available in a vast range of sizes. Be it solid rods or medium to thick wall tubes RAM extruders is the choicest option.

Application of RAM Extrusion
Profiles made out of RAM extrusion process are used in a number of critical engineering applications. From pump sets, small valves, bushes, seals, connectors, plain bearings, insulators etc. The uses are many. Another emerging sector that uses profiles made out of RAM extrusion process is the medical industry.