Users of Microvellum set their nesting optimization ‘Strategy’ option to ‘Small Parts to Center’ for various reasons, including safety and accuracy. However, this option is often misunderstood. This article explains what the percentage value represents and how to set it to achieve your objectives in using it.
When the option is set to ‘Small Parts to Center,’ the optimizer uses the ‘Small Part Threshold’ property to determine what qualifies as a small part. The optimizer first identifies and creates a collection of ‘small parts’ defined by the Small Part Threshold value. It then locates those small parts in the center of the sheet. Lastly, it collects all the parts that are larger than the small part threshold and places them around the perimeter of the sheet, outside the area defined for the small parts.
The value for ‘Small Parts % Buffer From Sheet Edge’ is crucial if you want to predictably group your small parts in the center of the sheet. Look at Figure 1 below as an example.
The value of this property is set to 20. This value represents a percentage of the width and length of the sheet.
By entering a value of 20 as shown in Figure 1, you are identifying the border of the ‘small parts area’ as being a distance of 20% of the sheet width from each long edge, and a distance of 20% of the sheet length from each short edge.
Therefore, if you have a sheet that measures 48 inches wide and 96 inches long, your area for small parts is 28.8 inches wide and 57.6 inches long.
The distance from both the long edges is 9.6 inches, and the distance from both short edges is 19.2, as shown in Figure 2 below.
The red rectangle represents the area where the optimizer will place the small parts. Make sure this area is larger than your largest ‘small part’ as defined by ‘Small Part Threshold.’ If you have a part that is larger than that size, it will fail to optimize as expected.