Extrusion processing is a manufacturing technique used to create objects of a fixed shape and size from molten or semi-molten material. In extrusion, the material is forced through an opening in a die (a shaped disk) with significant pressure, which gives it its characteristic columnar shape. The process usually occurs inside an extrusion line—a grouping of machines that continuously feed and mold the plastic into specific shapes as it moves.
Extrusion has many advantages over other plastics forming techniques such as injection molding: it’s extremely fast, can produce high volumes of parts with superb quality, and doesn’t require complex tooling. This makes extrusion ideal for producing products in large quantities continuously.
Typical extruded products include
Extruded products by Bausano are materials forced through a die to create a specific shape. The most common extrusion type is probably aluminum or plastic siding, which is created by forcing the material through a huge metal die at high temperatures. Other extruded products include window frames, tubing, plumbing pipes, and fence rails.
The extrusion process begins with molten material pouring into an open-ended barrel called a hopper. A screw inside the barrel moves the material forward as it rotates, pushing it against a fixed plate known as the dies—which determines the product’s final shape. As the screw turns, it also heats the material so that it remains in liquid form while being forced through narrow openings in the dies (the narrower these openings are dimensionally speaking), after which point cooled air is blown onto them to solidify them rapidly into their finished state.
One advantage of using extruded shapes over molded ones for various applications is that they can often be produced faster and more cheaply on an industrial scale; this has led to widespread use of extruded plastics across many industries, from construction to agriculture packaging.
Auxiliary equipment in extrusion processing
Auxiliary equipment in extrusion processing plays a significant role in ensuring the quality of the final product. The function of auxiliary equipment includes cooling and heating, measuring and controlling thickness, shaping products, removing moisture from materials, conveying products, and supplying material to the Extruder.
Cooling and Heating
The Auxiliary Equipment that is used for cooling and heating affects both the texture as well as color stability of an extruded product. Cooling can happen using various means such as air knives or water baths, whereas heating methods most commonly use steam or thermal oil. Regarding temperature uniformity across different parts of an extrudate profile, it is important to have heated zones placed close to where the die face meets mandrels/rollers (i.e.). Additionally, properly cooled end-products are essential, especially if subsequent forming processes are applied downstream. For example, excessively cooled profiles might lead to severe problems while bending pipes due to excessive brittleness attributed to low temperatures near external surface areas.
Read more: Extrusion Lines for Plastic Processing: What You Need to Know