Many thanks to this site. I have learned lots of info how to install floors.
Here is the procession how engineered wood floor is made?
1,Checking solid veneer
The items including MC,thickness,wideness,length,defects
2,Condition
Putting solid venner and plywood in condition room about 1 week. The temperature of the room is around 40 c. The purpose of condition is to control floors panel's MC. It's very good if the top layer's MC is the same as plywood's. It means more stable and no distortion in future.
3,Lamination
Solid venner was glued to plywood,then pressing. Some factories used hot pressing. And others used cold pressing. My own preference is cold pressing. Because the glue used in cold pressing is much more environmental friendly.
There are several kinds of plywood such as birch,poplar,mix hardwood,eucalyptus. Birch plywood is better than any others and most expensive.The glue used in plywood is usually WBP glue,melamine glue or MR glue.
4,T&G
Making tongue and groove. It's a very important procssion.Good quality floors always fit together well. Most floors in USA market is micro beveled. Suare edge is widly used in Italy and German market.
5,Sanding
make the surface be smooth and suitable for panting
6,Panting
Usually 7 coating layers(5 bottom and 2 face)