File Combined Board Properties

When you sit down with your sheet supplier(s) to begin the process of establishing combined board properties consider the following as guidelines for the properties listed below:

Edge Crush Test: You need 20% more vertical compression coming in the front door to overcome the rigors of the normal converting processes so that you can be comfortable that the grade you stamp on the bottom of the box is actually what is provided.

Flat Crush Test:  Ask for 35 psi.

Warp:  No more than 1/8 inch per foot.

Pin Adhesion:  Seek 60 pounds per linear floor of glue line.

Caliper: Inquire into the ranges for each board combination.

Flexural Stiffness or Four Point Bending:  This is a test which only a few labs can perform, but it is critical to the performance to the displays and graphics you produce. 
      200# Mullen test should have a MD average of 112 and a CD average of 52
      275# Mullen test should have a MD average of 157 and a CD average of 79
      32# ECT should have a MD average of 85 and a CD average of 41
      44# ECT should have a MD average of 132 and a CD average of 65