Slot Limitations:
Extruding temperatures of 1200 to 1800 F and pressures of 40,000 to 120,000 psi tax the strength of die materials to their limits. This is especially true for dies designs which have a deep, narrow tongue to form a groove or slot in the finished extrusion. It is usually necessary to limit depth-to-width ratios of slots and grooves to 2:1 for group 'A' extrusions and 1:1 for group 'B' extrusions.

Section Ratios:
Because of metal-flow properties, a shape which has a long, thin section joined to a larger solid section is difficult to extrude. This type of design should be avoided. The only solution is to increase the thickness of the thin section to uniformly allow for adequate metal flow.

Combining Parts:
Very large or hollow shapes can sometimes be designed as an assembly consisting of two or more parts fastened or joined together. Joint designs may be butt or some type of interlock.

Weight Per Foot:
As the weight per foot of the extrusion becomes lighter, it becomes more difficult to extrude. Mutliple holes must be put in the die which creates problems controlling the extrusions coming out of the press. In addition, press pressure become higher.Circle Size:
The maximum diameter of a circumscribing circle for extrusions is 6 inches. In some cases we can extrude a larger size by designing the die with a fold in the profile. After extruding the shape is rolled to its full width. Because of metal flow properties and pressure limitations, certain minimum thicknesses are required.

Metal Dimension Tolerances:
In addition to tolerances on metal dimensions, it is necessary to consider tolerances for space dimensions. Space tolerances are double metal tolerances. Please see our tolerances page for details on all of our mill tolerances.