Consideration must also be given to the processing factor. This factor is obtained by calculating the ration of ingot area to runout extrusion area. The optimal processing factor is between 30 and 50.
At values in excess of 80, the start pressure for tools and equipment increases to critical levels. This means that an 8″ ingot produces a total runout weight of 1.1 kg/m, and a 10″ ingot 1.7 kg/m.
At values below 7, the necessary mechanical conversion is insufficient to ensure the required material characteristics without implementing special measures. In the case of an 8″ ingot, this produces a maximum extrusion weight of 12.5 kg/m, and a for 10″ ingot a maximum of 19.6 kg/m.
To calculate the relative compactibility of an extrusion, you can use the numerical value obtained from the ratio total perimeter / extrusion weight for that extrusion. “Total perimeter” refers to the total interior and exterior perimeter of the extrusion.
This produces a form factor that can be easily compared with that of an existing extrusion. Although this method does not fully take into account factors such as a symmetry and uneven material distribution, it does provide a rough comparison value.
The lower the value, the easier it is to compact. Some comparison values are shown in the table below:
|Extrusion||weight (kg/m)||perim.(mm)||form factor|
|Round stock Ø80||13,57||251||18,5|