Reduce Panel Warping Due to Lamination

There are several things that must be observed to prevent the warping on panels after the lamination process both by both hot press or cold press. Make sure before pressing:

1. Must be balanced on both front and back lamination panel core, such as MDF panel core laminated with veneer 0.6mm on both sides face and back. When thickness was different, it will prone to warping. 
2. Veneer must be the same species, likewise to the slicing type e.g. both flat cut or quarter cut equally on two sides of panel core.
3. EMC both panel core and veneer material not more than 8% (ideally 6%). Moisture content difference should no more than 1%.
4. If panel core surface needs to be sanded before hot press due to wooden edge band, manage sanding depth of cut as thin as possible, not more than 0.5mm and it must be evenly sanded on both sides. 

Make sure after lamination process:

1. Provide spacer for panels releasing stress and heat (when hot pressed) with the same spacing and thickness. Place pallet on a flat/balance floor.
2. Acclimatization approximately 1 hour after hot press prior to further processes such as sanding and finishing.
3. Should WIP hold quite long before continued with next steps, then place WIP in controlled room which has air conditioner and dehumidifier. If necessary cover it tightly with plastic wrap in order to minimize the moisture absorption.

Is it correct to make MDO cross band with seams?

It is not easy making veneered panels. Many key procedure needs to be consistently followed. Veneered panels could be easily rejected due to gummed tape marks obviously seen once stained. People might be thinking that sanding panel to remove gummed tape with wide belt sander or stroke sander after hot pressed was improperly done. Or they thought that the gummed tape absorbed water too much and left the marks on face veneer. Then the panel re-sanded, but it didn't work,  as marks still there even more obvious. Face veneer getting thinner and thinner, and finally it easily loosed after few steps in finishing.

Why is that? The more sanded the more obvious! Please check, maybe there is the seams on MDO cross band, which was joined with gummed tape? This gummed tape is unlikely sanded after pasted on panel, as usually its thickness is only 0.3mm. People then easily guessed, they made 2 ply face veneer with gummed tape still stick underneath, and pasted it on core panels. What's the result? Yes! It will appear clearly after stained, and can't be removed unless remove all veneer + MDO and put the new 2 ply veneer with correct way.

Remember! Never put seams on MDO cross band whatever the reasons. If MDO sheet can't cover all core surface, put veneer cross band as the alternative way. Paste veneer cross band to the panel core first before paste it with face veneer.