EXAMPLE: Using a function for controlling a 90-degree folding correction

IMPORTANT: To use the functions of a parameter template, the material that you are using must carry this template.

When the internal size of a corrugated board structure needs to have exact dimensions, the distances between the corresponding crease lines must be extended by a 90-degree folding correction. The value of this correction depends on the thickness of the corrugated material.

There are different views among packaging producers as to how to calculate this correction: Some believe it must be half of the material thickness (Producer 1); others contend that the thickness-correction relationship is not linear (Producer 2).

So that resizable structures can work according to how a producer wants them to, we will create a function for the 90-degree folding correction. Then producers can edit the function expression to match the set requirements.

To create a 90-degree folding correction function

1. In the parameter template used for the corrugated materials (in the Function tab), create a function — for example, PCI90(d).

NOTE: We will cover the two cases that correspond to a different approach of controlling the 90-degree folding correction.

Producer 1: The folding correction is half of the material thickness

In this case, the function's expression would look like this:

PCI90(d) = d/2

Producer 2: The folding correction depends on the material thickness (non-lenear)

In this case, the function's expression would look like this:

PCI90(d) = switch(d; flF; 1; flE; 1; flB; 2; flC; 2.5; flEB; 2.5; flA; 3.5; flEC; 3.5; flBC; 4.5)

The function reflects the following dependencies:

In the images, the highlighted rows refer to the cases of the  two producers.

2. Proceed to use this function in the expression of the parameters that control the distances between the crease lines. This way each producer can edit — only one time — the function in the parameter template according to how they view the role of the 90-degree-folding correction.

NOTE: Editing the function is automatically reflected on the structure's 2D drawing in all resizable designs that use this function.

The following picture shows the two approaches for customizing the expression of the function for the correction of the 90-degree folding. In the design, the function is used in the expression of the parameters controlling the length and width of the structure. The red lines indicate the use of the function PCI90(d), with an expression specified by Producer 1. The blue lines indicate the use of the same function, this time with an expression specified by Producer 2.

NOTE: When we use the function in the expression of a parameter, for argument we must use a parameter or another function that the program recognizes. In this case, the d() function is used, which extracts the thickness of the material used for the project.