Designing Aluminum Extrusions

SHAPE CONFIGURATION

One of the major advantages of aluminum extrusions is that they can be designed in virtually any shape that meets the designer's structural and aesthetic requirements. They can be designed to aid in assembly, reduce or eliminate forming or welding operations, reduce machining requirements, and many other purposes.

There are three general classifications of extruded shapes: solid, semihollow, and hollow.

HOLLOW SHAPES

A hollow shape is a shape which completely encloses a void anywhere in its cross-section. Hollow shapes are sub-divided into three different classes.

Class 1 hollow shapes

There are three requirements for a shape to be classified as a Class 1 hollow:

• The internal void is round
• The void is one inch or more in diameter
• The shape is symmetrically balanced around the void by two or more axes

Class 2 hollow shapes

There are three different requirements for a shape to be classified as a Class 2 hollow:

• The shape is not a Class 1 hollow
• It has a single void no smaller than 0.375 inches in diameter or 0.110 square inches in area
• The entire shape fits within a 5 inch circumscribing circle

Class 3 hollow shapes

A Class 3 hollow is any hollow shape that cannot be classified as Class 1 or Class 2. For example, a shape with multiple voids would be a Class 3 hollow.

SEMIHOLLOW SHAPES