Considerations During Design Of Extrusions

Extrusion is a process where a material is pushed through a die using a mechanical or hydraulic pressresulting infinished products of a uniform cross section. The product can either be hollow or solid. Usually the materials used for this purpose should not become brittle under compression and shear stress.Some commonly used materials are metals, ceramics, polymers and food stuffs. The finished products are usually known as ‘extrudates’. The advantage of this method is that you can either produce extrudates of extreme length or several short ones with uniform dimensions.

Raw material

In ceramics extrusion is usually used to make tiles. The property of the finished tile will depend on both the type of clay used and the manufacturing process. In plastic or polymer extrusion the choice of polymer used will depend on the requirements of the final product. Unlike the above, in metal extrusion aluminium is the metal of choice for most applications. Aluminum extrusions have many desirable properties including highresistance to corrosion under regular environmental conditions, its highly malleable and ductile properties and high strength to weight ratio.

Thickness of the wall

The required thickness and uniformity of the wall will decide the cost efficiency of the process. Those with uniform thickness and symmetric shapes are the easiest to produce. Narrow deep channels that run the length of the extrudate, sharp corners and having walls of differing thickness will increase the cost of production. Instead of sharp corners they should be radiused. Soft edgedshallow channels are preferable to deep channels. Of course, these features may be incorporated into the design based on requirement, but they will be an added cost. For an instance, anbest aluminum profile for gate might need sharp lines to fit in to a window.

Other factors that affect the wall thickness are the force and speed applied during the manufacturing process, the type of metal or alloy used and the finishes on the product.

Usage of soft lines

Any parts of the extrudate that juts out of the finished product should have soft lines. If not, these will show deformations upon cooling.

Solid vs. hollow

Hollow structures are more complicated and more expensive to produce than solid structures. Also the strength and stability of the final product increases as the number of cavities inside an extrudate decreases. In the instance that a design requires a large number of cavities within the structure, then it is more cost effective to make the design as two concentric rings and then assemble them.

Decorations

Decorations on extrusions provide the dual purpose of beautifying the final product and also hiding all blemishes.

Extrusion is a great way of producing structures of complex designs. They offer versatility that most other manufacturing processes don’t offer.