When a veneer is bonded to both sides of the panel each side is equally expanding and contracting and thus the panel is balanced the stress of the wood cell movement is similar on both sides of the panel.
Balanced laminate panel.
Melamine paper is thermally bonded to particleboard or mdf panels.
This is produced in higher volumes than hpl.
Laminate orientation code repeating groups of plies within a laminate can be placed in parentheses.
Each complete laminate is enclosed in a set of brackets symmetric laminates with an even number of plies are represented by listing all plies on one side of the mid plane enclosed in brackets followed by the subscript s.
If the laminate is not balanced and symmetric macro warpage will certainly occur during cool down.
An example of a balanced laminate is 0 45 45 90 45 45 0 whereas an unbalanced laminate would be 0 45.
A balanced laminate is one that for every θ ply in the lay up there is an equivalent θ ply in the lay up.
We buy pre laminated panels as much as possible almost always with laminate both sides.
Sometimes a brown backer is applied to the bottom if color is not needed.
No science that i know of but in my experience an unbalanced panel is more prone to warping than a balanced panel.
If the laminates are of different thickness they will shrink at different rates pulling the panel out of flat.
My theory in a laminate panel all three plies laminate core laminate are moving seasonally.
Here is a deeper explanation of both reasons for using a balance veneer.
Tfm must be applied to the front and back of the panel to keep the panel balanced.