Roland GR-640 User Manual page 433

You can now enter the values.
Enter the Perforated Cutting Conditions.
Set the length of each perforation to make in the material (the perforation
length) and the length of the part that is not perforated because the blade force
is reduced (the half-cut length).
Adjust the half-cut force to suit the type of material or paper used.
Perforation Length/Half-cut Length
*1: Perforation length
*2: Half-cut length